Endohedrally Doped Cage Clusters
- Jijun Zhao
Jijun ZhaoKey Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, ChinaMore by Jijun Zhao
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- Qiuying Du
Qiuying DuKey Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, ChinaMore by Qiuying Du
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- Si Zhou*
Si ZhouKey Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, ChinaMore by Si Zhou
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- Vijay Kumar*
Vijay KumarCenter for Informatics, School of Natural Sciences, Shiv Nadar University, NH-91, Tehsil Dadri, Gautam Buddha Nagar 201314, U. P., IndiaDr. Vijay Kumar Foundation, 1969 Sector 4, Gurgaon 122001, Haryana, IndiaMore by Vijay Kumar
Abstract
The discovery of carbon fullerene cages and their solids opened a new avenue to build materials from stable cage clusters as “artificial atoms” or “superatoms” instead of atoms. However, cage clusters of other elements are generally not stable. In 2001, ab initio calculations showed that endohedral doping of Zr and Ti atoms leads to highly stable Zr@Si16 fullerene and Ti@Si16 Frank–Kasper polyhedral clusters with large HOMO–LUMO gaps. In 2002, Zr@Ge16 was shown to form a Frank–Kasper polyhedron, suggesting the possibility of designing novel clusters by tuning endohedral and cage atoms. These results were subsequently confirmed from experiments. In the past nearly two decades, many experimental and theoretical studies have been carried out on different clusters, and many very stable cage clusters with possibly high abundance have been found by endohedral doping. Indeed in 2017, Ta@Si16 and Ti@Si16 cage clusters have been synthesized in bulk quantity of about 100 mg using a dry-chemistry method, giving rise to a new hope of developing cluster-based materials in macroscopic quantity besides the well-known C60 fullerene solid. Also, wet-chemistry methods have been used to synthesize endohedrally doped clusters as well as ligated clusters and their solids, which auger well for the development of novel nanostructured materials using atomically precise clusters with unique properties. In this comprehensive review, we present results of many such developments in this fast-growing field including (i) endohedrally doped Al, Ga, and In clusters, (ii) small endohedral carbon fullerene cages with ≤ 28 carbon atoms, (iii) metal doped boron cages, (iv) endohedrally doped cages of group 14 elements (Si, Ge, Sn, and Pb), (v) coinage metal (Cu, Ag, Au) cages doped with a transition metal atom as well as their ligated clusters and crystals, (vi) endohedrally doped cages of compound semiconductors, and (vii) multilayer Matryoshka cages and core–shell structures. In a large number of cases, we have performed ab initio calculations to present updated results of the most stable atomic structures and fundamental electronic properties of the endohedrally doped cage clusters. We discuss electronic, magnetic, optical, and catalytic properties in order to shed light on their potential applications. The stability of the doped cage clusters has been correlated to the concept of filling the electronic shells for superatoms such as within a spherical potential model and also using various electron counting rules including Wade–Mingos rules, systems with 18 and 32 electrons, and the spherical aromaticity rule. We also discuss cluster–cluster interaction in cluster dimers and assemblies of some of the promising doped cage clusters in different dimensions. Finally, we give a perspective of this field with a bright future.
1. Introduction
2. Theoretical Methods and Models
2.1. Methods of ab Initio Calculations on Clusters
l0 (Å) | ωe (cm–1) | Mt (μB) | |
---|---|---|---|
B2 | 1.62 (1.59) | 1018.7 (1058) | 2 (2) |
C2 | 1.31 (1.31) | 1709.6 (1641.4) | 2 (2) |
Al2 | 2.48 (2.49) | 349.9 (345) | 2 (2) |
Si2 | 2.15 (2.25) | 562.4 (511) | 2 (2) |
Ge2 | 2.38 (2.34) | 293.5 (286) | 2 (2) |
Cu2 | 2.24 (2.22) | 261.5 (266.5) | 0 (0) |
Ag2 | 2.58 (2.53) | 185.7 (192) | 0 (0) |
Au2 | 2.55 (2.47) | 171.1 (190.9) | 0 (0) |
The calculated values are based on the PBE0 functional accompanied with 6-311+G(d) basis sets for B, C, Al, Si, and Ge atoms and SDD basis sets for Au, Ag, and Cu atoms using the Gaussian09 package.
2.2. Electron Counting Rules for Endohedral Clusters
2.2.1. 18-Electron and 32-Electron Rules
2.2.2. Spherical Aromaticity Rule
2.2.3. Electronic Shell Model within a Spherical Potential or Jellium Model
2.2.4. Wade–Mingos Rules
3. Endohedral Clusters Of Al, Ga, AND In
3.1. Endohedral Clusters of Al—Development of Metal Clusters as Superatoms
Cluster, Ne | Position of dopant | Eb (eV/atom) | AIP (eV) | AEA (eV) | EHL (eV) |
---|---|---|---|---|---|
[Al@Al12]−, 40 | 2.495* | 3.425* (3.62* Expt. [ (196)]), (3.57* ± 0.05 Expt. [ (160)]) | 2.972 | ||
[B@Al12]−, 40 | C | 2.733* | 3.218* | 3.148 | |
[Ga@Al12]−, 40 | C | 2.471* | 3.438* | 3.088 | |
C@Al12, 40 | C | 2.930 | 6.491 | 1.461 | 3.076 |
Si@Al12, 40 | C | 2.796 | 6.885 (>6.42<7.90 Expt. [ (20)]) | 1.873 (1.69 ± 0.07 Expt. [ (159)]) | 3.170 |
Ge@Al12, 40 | C | 2.720 | 6.772 | 1.869 (2.386 ± 0.008 Expt. [ (160)]) | 3.167 |
Al12In, 39 | V | 2.450 | 6.321 | 3.356 | 1.521 |
Al12Sn, 40 | V | 2.661 | 6.743 | 2.387 | 2.704 |
Al12Sb, 41 | V | 2.525 | 5.804 | 2.117 | 1.982 |
Al12Tl, 39 | V | 2.415 | 6.209 | 3.232 | 1.484 |
Al12Pb, 40 | V | 2.639 | 6.671 | 2.404 | 2.659 |
Al12Bi, 41 | V | 2.514 | 5.789 | 2.070 | 2.014 |
[N@Al12]+, 40 | C, V nearly degenerate | 2.887* | 6.355* | 1.608 | |
[P@Al12]+, 40 | C | 2.736* | 5.118* (5.37* ± 0.04 Expt. [ (159)]) | 3.306 | |
[Al12As]+, 40 | V, C nearly degenerate | 2.695* | 5.674* | 3.214 | |
Cu@Al12, 37 | C | 2.436 | 6.551 | 2.984 | 1.684 |
Al12Ag, 37 | layer | 2.392 | 6.312 | 2.867 | 1.443 |
Al12Au, 37 | C | 2.455 | 6.253 | 2.933 | 1.389 |
Cu@Al13, 40 | C | 2.571 | 6.594 | 2.137 | 2.817 |
Al12Sc, 39 | V | 2.543 | 5.964 | 2.543 (2.53 Expt. [ (197)]) | 1.550 |
Al12Ti, 40 | V | 2.494 | 6.200 | 2.729 | 1.677 |
Ag&Al13, 40 | Cap | 2.528 | 7.168 | 2.028 | 2.893 |
Au&Al13, 40 | Cap | 2.585 | 6.601 | 2.059 | 2.822 |
Li&Al13, 40 | Cap | 2.519 | 6.719 | 1.940 | 2.895 |
Na&Al13, 40 | Cap | 2.491 | 6.351 | 1.794 | 2.931 |
K&Al13, 40 | Cap | 2.503 | 6.253 | 1.620 | 2.916 |
Rb&Al13, 40 | Cap | 2.493 | 6.110 | 1.515 | 2.936 |
Cs&Al13, 40 | Cap | 2.499 | 5.989 | 1.436 | 2.921 |
Al@Al22, 69 | C | 2.667 | 5.988 | 3.168 | 1.229 |
Si@Al22, 70 | C | 2.792 | 5.889 | 2.765 | 1.726 |
[B@Al22]−, 70 | C | 2.747* | 5.884* | 3.065* | 1.888 |
“Cap” denotes that the dopant atom caps an icosahedral Al13, while “layer” means that the icosahedral structure transforms to a layered structure. Results for X@Al22 (X = Al, B, and Si) are for a decahedral structure. * represents that the number is for a neutral cluster. The available experimental values (expt.) are given for comparison. For a magnetic cluster, the total spin magnetic moment is also given. Ne is the number of valence electrons.
3.1.1. Electronic Structure and Bonding Requirement for Endohedral Doping
3.1.2. Open-Shell Cu@Al12 and Closed-Shell Cu@Al13 Superatoms
3.1.3. X@Al12 with a Divalent Atom X—The Superchalcogens
3.1.4. Endohedrally Doped Aluminum Clusters and Hydrogen Storage
3.1.5. Al12X with a Transition Metal Atom X
3.1.6. Optical Absorption of X@Al12 Clusters and Derivatives
3.1.7. Catalytic Behavior of X@Al12 Clusters
3.1.8. Larger Doped Clusters of Aluminum
3.2. Endohedrally Doped Clusters of Ga and In
4. Endohedrally Doped Carbon and Boron Fullerene Cages
4.1. Metal Encapsulated Small Carbon Fullerenes M@Cn, n = 20–28
Cluster | Method | Symmetry | M–C (Å) | ν (cm–1) | Eem (eV) | EHL (eV) | Q (|e|) |
---|---|---|---|---|---|---|---|
Li@C24 [ (266)] | B3PW91/6-31G(d) | C2 | 1.65 | 1.33 | –0.26 | ||
Be@C24 [ (266)] | B3PW91/6-31G(d) | Cs | 1.51 | 2.08 | 0.70 | ||
Sc@C24 [ (268)] | B3PW91/6-31G(d) | D2d | 2.214 | 85.4 | 4.16 | 1.44 | 0.05 |
Ti@C24 [ (267)] | B3PW91/6-31G(d) | Cs | 2.027 | 121.3 | 5.18 | 1.73 | 0.39 |
Cr@C24 [ (269)] | B3PW91/6-31G(d) | Cs | 1.861 | 151.4 | 5.07 | 2.70 | 0.51 |
Fe@C24 [ (270)] | B3PW91/6-31G(d) | Cs | 1.828 | 174.1 | 1.25 | 1.81 | 0.89 |
Zr@C24 [ (267)] | B3PW91/6-31G(d), LanL2DZ | S4 | 2.236 | 76.5 | 3.22 | 1.47 | 1.63 |
Mo@C24 [ (269)] | B3PW91/6-31G(d), LanL2DZ | Cs | 1.994 | 74.7 | 2.40 | 2.36 | 0.64 |
Hf@C24 [ (267)] | B3PW91/6-31G(d), LanL2DZ | S4 | 2.228 | 80.0 | 4.02 | 1.47 | 1.79 |
W@C24 [ (269)] | B3PW91/6-31G(d), LanL2DZ | Cs | 2.021 | 39.8 | 3.54 | 2.44 | 1.37 |
The shortest distance between M atom and C atom (M–C), lowest harmonic vibrational frequency (ν), embedding energy (Eem), HOMO–LUMO gap (EHL), and on-site charge (Q) on M atom have been given. A positive value of Q means electrons are transferred from M atom to C24 cage.
4.2. Endohedrally Doped Cages of Boron
Cluster | Method | Symmetry | EHL (eV) | Q (|e|) | Eem (eV) | VIP (eV) | VEA (eV) |
---|---|---|---|---|---|---|---|
Ca@B40 [ (306)] | PBE0/6-311+G(d) | C2v | 1.60 | 3.565 | 5.94 | ||
Sr@B40 [ (306)] | PBE0/6-311+G(d) | D2d | 1.58 | 3.404 | 5.90 | ||
Sc@B40 [ (307)] | PBE/6-311+G(d), LanL2DZ | Cs | 0.44 | 5.516 | 5.90 | 2.39 | |
Y@B40 [ (307)] | PBE/6-311+G(d), LanL2DZ | C2v | 0.40 | 5.902 | 5.74 | 2.38 | |
La@B40 [ (307)] | PBE/6-311+G(d), LanL2DZ | C2v | 0.32 | 5.880 | 5.67 | 2.38 | |
Na@B40[ (308)] | PBE0/6-311+G(d) | C2v | 1.45 | 0.89 | 1.479 | 5.69 | 2.43 |
Ba@B40 [ (308)] | PBE0/6-311+G(d), SDD | D2d | 1.63 | 3.768 | 6.19 | 2.39 | |
Zn@B40 [ (320)] | PBE/6-31G(d), LANL2DZ | C2v | 1.00 | 1.806 | |||
Sc3N@B40 [ (309)] | B3LYP/6-31G(d,p) | C2v | 1.50 | 5.23 | |||
Sc2C2@B40 [ (309)] | B3LYP/6-31G(d,p) | C1 | 1.13 | 5.08 | |||
Ti@B40 [ (312)] | PBE/6-311+G(d), SDD | C1 | 0.74 | 0.37 | 5.112 | ||
Ti2@B40 [ (312)] | PBE/6-311+G(d), SDD | Cs | 0.86 | 1.17 | 9.319 | ||
Eu@B40 [ (313)] | PBE/6-311+G(d), CEP-31G | D2d | 0.72, 0.76 | 0.86 | 4.185 | 6.13 | 2.21 |
Gd@B40 [ (313)] | PBE/6-311+G(d), CEP-31G | Cs | 0.84, 0.36 | 0.88 | 4.883 | 5.79 | 2.38 |
Ba@B40 [ (314)] | PBE+TS/DNP | D2d | 0.74 | 3.953 | |||
U@B40 [ (315)] | PBE/TZ2P | D2d | 0.76 | 0.53 | 8.22 |
For Eu@B40 and Gd@B40, the molecular orbitals are spin polarized and two values of EHL corresponding to spin-up and spin-down states are given. A positive value of Q means electrons are transferred from the M atom to the B40 cage.
Cluster | Method | Symmetry | EHL (eV) | Q (|e|) | Eem (eV) | VIP (eV) | VEA (eV) |
---|---|---|---|---|---|---|---|
Ti@B28 [ (305)] | PBE/6-311+G(d), LanL2DZ | C1 | 1.58 | 8.01 | 7.32 | 2.23 | |
La@B38 [ (305)] | PBE/6-311+G(d), LanL2DZ | D2h | 0.63, 0.68 | 4.08 | 5.93 | 2.38 | |
U@B36 [ (321)] | PBE0/6-311+G(d), ECP60MWB-SEG | C2h | 2.80 | 0.66 | 9.10 | 6.10 | 2.15a |
[Ca@B37]− [ (322)] | CCSD(T)/6-311G(d) | Cs | 1.94 | 1.71 | |||
Gd@B38 [ (313)] | PBE/6-311+G(d), CEP-31G | C2h | 0.58, 0.76 | 0.219 | 6.57 | 5.94 | 2.30 |
Th@B38 [ (321)] | PBE0/6-311+G(d), ECP60MWB-SEG | D2h | 1.70 | 0.42 | 9.67 | 5.89 | 1.87a |
Sc@B38 [ (323)] | PBE/DNP | C2v | 0.58 | 5.22 | 6.05 | 2.47 | |
Y@B38 [ (323)] | PBE/DNP | C2v | 0.45 | 5.54 | 5.96 | 2.39 | |
Ti@B38 [ (323)] | PBE/DNP | C2v | 0.78 | 6.07 | 6.36 | 2.43 | |
Ca@B38 [ (324)] | PBE0/6-311G(d) | Cs | 2.70 | 1.69 | 5.538 | 7.35 | 2.44a |
[Ca@B39]+ [ (325)] | PBE0/6-311+G(d) | C3 | 3.06 | 1.58 | 5.18 | ||
FLi2@B39 [ (326)] | PBE0/6-311+G(2d) | C1 | 1.99 | 7.34 | 2.20 | ||
Ca@B44 [ (327)] | PBE/6-311+G(d) | C2 | 0.77 | 0.739 | 4.48 | 6.52 | 2.74 |
Sr@B44 [ (327)] | PBE/6-311+G(d), LanL2DZ | C1 | 0.76 | 0.730 | 2.81 | 6.48 | 2.74 |
Ba@B44 [ (327)] | PBE/6-311+G(d), LanL2DZ | C1 | 0.73 | 0.756 | 2.93 | 6.50 | 2.77 |
The values of the HOMO–LUMO gap (EHL), on-site charge (Q) on M, embedding energy (Eem), VIP, and VEA are given. For Gd@B38, the molecular orbitals are spin polarized and two values of EHL corresponding to spin-up and spin-down states are given. A positive value of Q means electrons are transferred from the M atom to the Bn cage.
ADE instead of VEA as given in refs (321and324).
Cluster | Method | Symmetry | EHL (eV) | Q (|e|) | Eem (eV) | VIP (eV) | VEA (eV) |
---|---|---|---|---|---|---|---|
Fe@B18 [ (333)] | TPSSh/6-311+G(d) | Cs | –1.00 | ||||
Fe@B20 [ (333)] | TPSSh/6-311+G(d) | Cs | |||||
Cr@B20 [ (337)] | PBE0/6-311+G(d), Stuttgart | D2d | 4.28 | ||||
Cr@B22 [ (337)] | PBE0/6-311+G(d), Stuttgart | Cs | 3.92 | ||||
[Mn@B20]+ [ (334)] | PBE0/6-311+G(d), Stuttgart | D2d | 4.53 | ||||
Zn@B20 [ (320)] | PBE/6-31G, LanL2DZ | C2 | 1.17 | 1.17 | 2.52 | ||
Mo@B22 [ (335)] | PBE0/6-311G(d), LanL2DZ | D2 | 3.84 | –0.76 | 8.26 | 1.61 | |
Mo@B24 [ (335)] | PBE0/6-311G(d), LanL2DZ | D3h | 3.75 | 8.33 | 1.30 | ||
Ru@B20 [ (336)] | PBE0/6-311+G(d), Stuttgart | C1 | 3.72 | –1.95 | |||
[Ta@B24]− [ (331)] | PBE0/6-311+G(d) , Stuttgart | C2v | 3.86 | –1.27 | |||
W@B20 [ (328)] | mPW3PBE/6-31G, LanL2DZ | C1 | 3.29 | –1.52 | 8.05 | ||
W@B24 [ (328)] | mPW3PBE/6-31G, LanL2DZ | D3h | 4.02 | –1.52 | 9.67 | ||
Mo@B24 [ (60)] | PBE0/6-311+G(d), Stuttgart | D3h | 4.21 | –2.75 | 8.00 | 1.20 | |
W@B24 [ (60)] | PBE0/6-311+G(d), Stuttgart | D3h | 4.18 | –2.59 | 8.03 | 1.26 |
The values of the HOMO–LUMO gap (EHL), on-site charge (Q) on M, embedding energy (Eem), VIP, and VEA are given. A negative value of Q means electrons are transferred from the Bn cage to the M atom.
5. Endohedrally Doped Silicon Cages
5.1. Theoretical Prediction of Doped Silicon Cages
Method | System |
---|---|
HF/6-31G(d) | CuSin (n = 4, 6, 8, 10, 12, 14) [ (477)] |
MP2/6-31G(2df, p) | CuSin (n = 4–10) [ (445)] |
Quantum Monte Carlo | Cr@Si12 [ (368)] |
LDA/Gaussian orbital basis set | Zr@Si20 [ (46)] |
LDA/TZP | [TaSin]+ (n = 1–13, 16) [ (388)] |
GGA/TZ2P | MSin (n = 1–14; M = Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir) [ (375)] |
BP86/TZP | TaSin (n = 1–13) [ (382)]; YSin (n = 1–16) [ (407)]; M@Si12 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) [ (448)] |
BP86/6-311+G(d) | [Mn@Si14]+ [ (474)] |
B3P86/6-311+G(d) | M@Si12 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) [ (451)] |
PW91/planewave | MSin (n = 14–17; M = Cr, Mo, W) [ (358)]; MSin (n = 8–12, 14; M = Be, Mg, Zn, Cd, Sn, Mn) [ (67)]; YSin (n = 4–20) [ (370)]; M@Si10 (M = Ni, Pd, Pt) [ (58)]; CrSin (n = 8–17) [ (362)]; MSin (n = 8–16; M = Ti, Cr) [ (364)]; MSin (n = 8–16; M = Ti, Zr, Hf) [ (365)]; Th@Si20 [ (366)]; MSi20 (M = Y, La, Sm, Gd, Tm, Ac) [ (367)]; W@Si12, Ti@Si15, Ti@Si16 [ (395)]; M@Si12 (M = Ti, Cr, Zr, Mo, Ru, Pd, Hf, Os) [ (435)] |
PW91/DNP | CoSin (n = 2–13) [ (387)]; FeSin (n = 2–14) [ (389)]; CoSin (n = 2–14) [ (399)]; LaSin (n = 1–21) [ (408)]; EuSin (n = 1–13) [ (413)]; NiSin (n = 1–17) [ (416)]; MnSin (n = 1–15) [ (420)]; Eu@Si20 [ (422)]; GdSin (n = 1–17) [ (428)]; HoSin (n = 1–12, 20) [ (437)] |
PW91/TZP | MSin (n = 1–14; M = Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Pt, Cu, Ag, Au) [ (394)] |
PW91/LanL2DZ | MSin (n = 9–20; M = Ti, Zr, Hf) [ (410)]; MSin (n = 14–20; M = Ti, Zr, Hf) [ (411)]; MSin (n = 8–20; M = Ti, Zr, Hf) [ (412)] |
B3PW91/LanL2DZ | M@Si16 (M = Ti, Zr, Hf) [ (359)]; M@Si12 (M=Hf, Ta, W, Re, Os, Ir, Pt, Au) [ (390)]; M2@Si20 (M = V, Cr, Co, Zr, Mo, Hf, Re, Fe, Os, Ni, Pd, Pt, Cu, Ag) [ (415)]; AuSin (n = 1–16) [ (423)] |
B3PW91/6-311G(d,p) | M@Si16 (M = Ti, Zr, Hf) [ (359)] |
B3PW91/6-311+G(d, p) | M@Si16 (M = Ti, Zr) [ (361)]; M@Sin (n = 15, 16; M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) [ (418)] |
PBE/NRLMOL basisa | CrSin (n = 11–14) [ (371)]; FeSin (n = 9–11) [ (377)]; FeSin (n = 1–14) [ (434)] |
PBE/planewave | W@Sin (n = 12, 14, 16) [ (374)]; MSin (n = 10, 12, 14; M = Nb, Ta, W) [ (378)]; Ti@Si16 [ (396)]; M@Si16 (M = Ti, Zr, Hf) [ (421)]; M@Si16 (M = La, Ce, Pr, Nd, Sm, Eu, Gd, Tm, Yb, Lu) [ (119)]; M@Si10 (M = Ni, Cu, Ag, Au) [ (436)]; M@Si12 (M = V, Nb, Ta, Cr, Mo, W) [ (436)] |
PBE/DNP | [VnSi12]− (n = 1–3) [ (443)]; [V3Sin]− (n = 3–14) [ (444)] |
PBE/DZVP | M@Si12 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) [ (385)]; [M@Sin]−/0/+ (n = 15–17; M = Sc, Ti, V) [ (391)] |
PBE/DZP | [ScSin]− (n = 14–18) [ (400)]; MSin (n = 14–18; M = Sc–, Ti, V+) [ (401)]; [Ta@Sin]+ (n = 14–18) [ (426)] |
PBE/TZ2P | CrSin (n = 6–16) [ (440)]; WSin (n = 6–16) [ (446)]; FeSin (n = 6–16) [ (447)]; [Fe2Sin]−/0/+ (n = 2–12) [ (459)] |
PBE/tier2 | [M@Si16]+ (M = Ti, Zr, Hf) [ (425)] |
PBE/6-311+G(d) | [CrnSi15–n]−/0 (n = 1–3) [ (460)]; [CoSin]−/0 (n = 3–12) [ (466)] |
BLYP/DNP | NiSin (n = 2–14) [ (398)]; MSin (n = 8–16; M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) [ (405)]; LaSin (n = 1–21) [ (408)]; Eu@Si20 [ (422)] |
B3LYP/cc-pVDZ | HoSin (n = 12–20) [ (452)]; [AuSin]− (n = 4–12) [ (454)] |
B3LYP/aug-cc-pVDZ | [Ti2Si20]−/0 [ (462)]; [Fe2@Si20]−/0/+ [ (465)] |
B3LYP/DGDZVP | [YSin]− (n = 6–17) [ (472)] |
B3LYP/TZP | Cr@Si12, Mn+@Si12 [ (449)] |
B3LYP/TZVP | Ni@Si12 [ (393)]; M@Sin (n = 10, 12; M = Zn, Cu, Ni) [ (397)]; Ni@Si12, Cu@Si12 [ (419)]; M@Si20 (M = U6–, Np5–, Pu4–, Am3–, Cm2–) [ (430)] |
B3LYP/aug-cc-pVTZ | M@Sin (n = 6–10; M = Be, B+, C2+) [ (470)] |
B3LYP/aug-cc-pVTZ-PP | [AuSin]− (n = 4–12) [ (454)] |
B3LYP/LanL2DZ | WSin (n = 1–6; 12) [ (373)]; M@Si20 (M = Ba, Sr, Ca, Zr, Pb) [ (363)]; MSin (8 ≤ n ≤ 20; M = W, Zr, Os, Pt, Co) [ (376)]; M@Si12 (M = Cu, Mo, W) [ (379)]; FeSin (n = 1, 2, 5, 6, 10, 12, 14) [ (380)]; MSin (n < 15, M = V, Fe, Ni) [ (383)]; ReSin (n = 1–12) [ (384)]; ZrSin (n = 1–16) [ (386)]; M@Si12 (M=Hf, Ta, W, Re, Os, Ir, Pt, Au) [ (390)]; M@Si10 (M=Ni, Pd, Pt) [ (392)]; Mo2Sin (n = 9–16) [ (402)]; TiSin (n = 2–15) [ (403)]; Zr2Sin (n = 16–24) [ (409)]; M2@Si20 (M = V, Cr, Co, Zr, Mo, Hf, Re, Fe, Os, Ni, Pd, Pt, Cu, Ag) [ (415)]; [AgSin]− (n = 3–12) [ (433)]; Pd2Sin (n = 10–20) [ (438)]; [V2Si20]−/0 [ (442)]; [NbSin]−/0/+ (n = 2–20) [ (450)]; [NbSin]−/0 (n = 3–12) [ (453)]; Pt2Sin (n = 10–20) [ (457)]; [Nb2Sin]−/0 (n = 13–20) [ (463)]; [Nb2Si20]−/0 [ (464)]; MSin (n = 10, 12, 14; M = Ag, Au) [ (473)] |
B3LYP/ECP28MWB | HoSin (n = 12–20) [ (452)] |
B3LYP/3-21G*(6d, 7f) | AgSin (n = 1–15) [ (429)] |
B3LYP/6-31G(d) | MSi10 (M = Li, Be, B, C, Na, Mg, Al, Si) [ (467)] |
B3LYP/6-31+G(d) | Cu@Sin (n = 9–15) [ (406)]; Cu@Sin (n = 9–14) [ (414)]; MSi14 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) [ (417)]; CuSin (n = 6, 8, 10, 12) [ (427)] |
B3LYP/6-311G(d) | MSi12 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Mo, W, Re, Os, Pt, Au) [ (381)] |
B3LYP/6-311+G(d) | CuSin (n = 4, 6, 8, 10, 12) [ (372)]; [CuSin]− (n = 4–18) [ (431)]; [CrSin]− (n = 3–12) [ (432)]; AgSin– (n = 3–12) [ (433)]; [ScSin]− (n = 6–20) [ (439)]; [NbSin]−/0/+ (n = 2–20) [ (450)]; [NbSin]−/0 (n = 3–12) [ (453)]; [Nb2Sin]−/0 (n = 13–20) [ (463)]; [Nb2Si20]−/0 [ (464)] |
B3LYP/6-311+G(2d) | MSi14 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) [ (417)] |
B3LYP/6-311+G(d, p) | M@Sin (n = 15, 16; M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) [ (418)] |
X3LYP/ECP56MHF | HoSin (n = 12–20) [ (441)] |
X3LYP/6-31G | HoSin (n = 12–20) [ (441)] |
HSE06/aug-cc-pVDZ, LanL2DZ | M@Si16 (M = Ti, Zr, Hf) [ (461)] |
mPW2PLYP/aug-cc-pVTZ | [ScSin]−/0 (n = 4–16) [ (458)] |
LDA, PBE, PBE0, B3LYP/planewave | M@Si20 (M = Ba, Ca, Cr, Cu, K, Na, Pb, Rb, Sr, Ti, V, Zr) [ (424)] |
PBE, BLYP, B3LYP/DZP, TZP | M@Si14 (M = V, Cr, Mn, Fe) [ (456)] |
Here M denotes the dopant atom, x is the number of M atoms, n is the number of Si atoms, and q is the charge on the cluster.
NRLMOL basis sets are Gaussian-type basis functions supplemented by a diffuse Gaussian with a six s, five p, and three d basis set for silicon and seven s, five p, and four d basis set for transition metal atoms, as implemented in the NRLMOL code. (478,479)
5.2. Experimental Characterizations of Doped Silicon Clusters
5.2.1. Mass Spectra and Adsorption Reactivity
M | Sin | Gen | Snn | Pbn |
---|---|---|---|---|
Cr | (15, 16)+ | (14, 15, 16)+ | (10-16)+, (10)0 | (10, 12)+,0 |
Mn | (15, 16)(+) | (14, 15, 16)(+) | (13, 16)+, (12)0,+ | (12)+,0 |
Cu | (10)+ | (7, 10)+ | (10)+,0 | (10, 12)+,0 |
Zn | (10, 12)0 | (12)0 |
The charge state is indicated in the superscript. Reproduced with permission from ref (483). Copyright 2006 Elsevier B.V.
Group 3 | Group 4 | Group 5 | |||||||
---|---|---|---|---|---|---|---|---|---|
cation | neutral | anion | cation | neutral | anion | cation | neutral | anion | |
3d | Sc: 17 | 15 | 15 | Ti: 13 | 13 | 11 | V: 12 | 10 | 9 |
4d | Y: 21 | 20 | 20 | Zr: 15 | 14 | 12 | Nb: 13 | 12 | 11 |
5d | Lu: 21 | 16 | 18 | Hf: 14 | 14 | 12 | Ta: 13 | 10 | 11 |
Reproduced with permission from ref (486). Copyright 2007 American Chemical Society.
5.2.2. Infrared Spectra
5.2.3. Photoelectron Spectra
5.2.4. X-ray Absorption Spectra and XMCD Spectra
5.2.5. Large-Scale Production of Ti@Si16 and Ta@Si16 Superatoms
5.2.6. Halide Ions as Template for Large-Scale Production of Silafulleranes
5.3. Endohedrally Doped Silicon Cages by Size from Calculations
5.3.1. Endohedrally Doped Si10 Cages
5.3.2. Endohedrally Doped Si11 Cages
5.3.3. Endohedrally Doped Si12 Cages
5.3.4. Endohedrally Doped Si13 Cages
5.3.5. Endohedrally Doped Si14 Cages
5.3.6. Endohedrally Doped Si15 Cages
5.3.7. Endohedrally Doped Si16 Cages
5.3.8. Endohedrally Doped Si18 and Si20 Cages
5.3.9. Cage Size vs Atomic Radius of Dopant Element
5.4. Physical and Chemical Properties of Doped Silicon Cages
6. Endohedrally Doped Cages of Ge, Sn, AND Pb
6.1. Doped Germanium Cages
Method | System |
---|---|
BP86/DZP | [Co2@Ge16]q (q = −4, −3, −2, −1, 0) [ (95)] |
BP86/TZP | [Co2@Ge16]q (q = −4, −3, −2, −1, 0) [ (95)]; M@Ge12 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd) [ (448)] |
PW91/planewave | Zn@Ge12 [ (528)]; MGen (n = 14, 15, 16; M = Ti, Zr, Hf, Pb, Cr, Mo, W, Fe, Ru, Os) [ (53)]; MGen (n = 8, 9, 10, 12, 14; M = Be, Mg, Zn, Mn) [ (67)]; M@Ge10 (M = Ni, Pd, Pt) [ (58)]; Th@Gen (n = 16, 18, 20) [ (529)]; MGen (n = 1–13; M = Mn, Co, Ni) [ (566)]; MGen (n = 9, 10; M = Si, Li, Mg, Al, Fe, Mn, Pb, Au, Ag, Yb, Pm, Dy) [ (582)]; [ZrGen]−/0 (n = 1–21) [ (583)]; |
PW91/DNP | CoGen (n = 1–13) [ (550)]; FeGen (n = 9–16) [ (553)]; MnGen (n = 2–16) [ (555)] |
PW91/LanL2DZ | [RuGen]− (n = 3–12) [ (534)] |
MPW91PW91/6-311+G | CoGen (n = 1–13) [ (550)] |
BPW91/LanL2DZ | M@Ge12 (M = Mn, Tc, Re, Zn, Cd, Hg) [ (590)] |
B3PW91/LanL2DZ | NiGen (n = 1–20) [ (559)]; [M@Gen]q (n = 14–20; M = Sc, Ti, V; q = −1, 0, +1) [ (561)]; CuGen (n = 1–20) [ (573)]; |
B3PW91/6-311+G(d) | MGen (n = 1–20; M = Ti, Zr, Hf) [ (572)]; [CoGen]−/0 (n = 2–11) [ (532)]; [VGen]−/0 (n = 3–12) [ (533)]; [FeGen]−/0 (n = 3–12) [ (537)] |
PBE/DNP | MnGen (n = 1–13) [ (551)]; MGen (n = 9, 10; M = Si, Li, Mg, Al, Fe, Mn, Pb, Au, Ag, Yb, Pm, Dy) [ (582)]; [Fe2Gen]−/0 (n = 3–12) [ (538)] |
PBE/DZ | VGen (n = 1–19) [ (584)] |
PBE/DZP | CrGen (n = 1–13) [ (570)]; VGen (n = 1–19) [ (584)]; MGen (n = 1–19; M = Cu, Ag, Au) [ (587)] |
PBE/LanL2DZ, cc-pVTZ | MGen (n = 1–19; M = Cu, Ag, Au) [ (587)] |
PBE/LanL2DZdp, 6-311G | CrGen (n = 1–17) [ (579)] |
PBE/6-311+G(d) | [Cr2Gen]−/0 (n = 3–14) [ (539)] |
PBE0/LanL2DZ | [RuGen] 2–/3– (n = 2–12) [ (589)] |
BLYP/DNP | M@Ge12 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) [ (562)] |
B3LYP/LanL2DZ | [CoGe10]− [ (544)]; MGe12 (M = Hf, W, Os, Ni, Zn) [ (545)]; CuGen (n = 2–13) [ (546)]; NiGen (n = 1–13) [ (547)]; WGen (n = 1–17) [ (548)]; Mo2Gen (n = 9–15) [ (552)]; HfGen (n = 9–24) [ (554)]; [M@Ge10]q (q = −4, −2, 0; M = Ni, Pd, Pt) [ (557)]; AuGen (n = 2–13) [ (558)]; [MGe10]−1/0 (M = Cu, Ag, Au) [ (563)]; [MGe10]+ (M = Cu, Ag, Au) [ (564)]; NiGen (n = 1–20) [ (574)]; [AuGen]− (n = 1–13) [ (575)]; MoGen (n = 1–20) [ (576)]; M@Gen (n = 10, 12, 14; M = Ag, Au) [ (473)]; NbGen (n = 7–18) [ (588)] |
B3LYP/DGDZVP | [NbGen]− (n = 8–20) [ (585)]; [ZrGen]− (n = 8–20) [ (586)] |
B3LYP/SDD | [TaGen]− (n = 8–17) [ (577)]; [HfGen]− (n = 6–21) [ (580)]; [AuGen]− (n = 2–12) [ (535)] |
B3LYP/6-31G | ZnGen (n = 1–13) [ (549)] |
B3LYP/6-31G(d) | [M@Ge10]q (q = −6, −5, −4, −3, −2, −1, 0, +1, +2; M = Ni, Cu, Zn) [ (556)]; [Be@Ge10]q (q = −2, 0, +2, +4) [ (565)]; [Co@Ge10]q (q = −5, −4, −3, −2, −1, 0, +1) [ (567)]; [Be@Ge10]q (q = −4, −2, 0, +2) [ (568)]; [Be@Gen]q (n = 6, 7, 8; q = −4, −2, 0, +2) [ (569)]; Be@Ge8[ (571)]; [Mn@Ge10]q (q = −5, −4, −3, −2, −1, 0, +1) [ (581)] |
B3LYP/6-311+G(d) | MGe12 (M = Li–, Na–, Be, Mg, B+, Al+)[ (560)]; [ScGen]− (n = 6–16) [ (578)]; [AuGen]− (n = 2–12) [ (535)]; [TiGen]− (n = 7–12) [ (536)]; [NbGen]− (n = 8–20) [ (585)]; [ZrGen]− (n = 8–20) [ (586)] |
B3LYP/6-311++G(3df) | Be@Ge8 [ (571)] |
Here M denotes the endohedral atom, x is the number of M atoms, n is the number of Ge atoms, and q is the charge on the cluster.
6.1.1. Endohedrally Doped Ge8 and Ge9 Cages
6.1.2. Endohedrally Doped Ge10 Cages
6.1.3. Endohedrally Doped Ge11 Cages
6.1.4. Endohedrally Doped Ge12 Cages
6.1.5. Endohedrally Doped Ge13 Cages
6.1.6. Endohedrally Doped Ge14 Cages
6.1.7. Endohedrally Doped Ge15 and Ge16 Cages
6.1.8. Endohedrally Doped Ge18 and Ge20 Cages
6.2. Doped Tin Cages
6.2.1. Endohedrally Doped Sn10 Cages
Cluster | Method | R (Å) | EHL (eV) | Eb (eV) | Eem (eV) | VIP (eV) |
---|---|---|---|---|---|---|
Ni@Sn10 [ (58)] | PW91/planewave | 1.24 | 3.15 | |||
Pd@Sn10 [ (58)] | PW91/planewave | 1.17 | 3.06 | |||
Pt@Sn10 [ (58)] | PW91/planewave | 1.30 | 3.24 | |||
Cu@Sn10 [ (563)] | B3LYP/LanL2DZ | 2.795, 2.977 | 2.68 | 3.76 | 6.14 | |
Ag@Sn10 [ (563)] | B3LYP/LanL2DZ | 2.880, 3.015 | 2.68 | 3.76 | 6.14 | |
Au@Sn10 [ (563)] | B3LYP/LanL2DZ | 2.883, 3.019 | 2.68 | 3.76 | 6.14 | |
[Cu@Sn10]− [ (563)] | B3LYP/LanL2DZ | 2.753, 3.204 | 2.39 | 2.87 | 5.80 | 3.11 |
[Ag@Sn10]− [ (563)] | B3LYP/LanL2DZ | 2.845, 3.218 | 2.16 | 2.71 | 4.01 | 2.99 |
[Au@Sn10]− [ (563)] | B3LYP/LanL2DZ | 2.848, 3.236 | 2.07 | 2.71 | 4.06 | 2.90 |
[Cu@Sn10]+ [ (564)] | B3LYP/LanL2DZ | 2.841, 2.784 | 2.0 | 2.43 | ||
[Ag@Sn10]+ [ (564)] | B3LYP/LanL2DZ | 2.917, 2.861 | 1.9 | 2.29 | ||
[Au@Sn10]+ [ (564)] | B3LYP/LanL2DZ | 2.915, 2.871 | 2.0 | 2.55 | ||
Zn@Sn10 [ (615)] | B3LYP/LanL2DZ | 2.35 | 2.44 | 1.00 | ||
Li@Sn10 [ (616)] | B3LYP/cc-pVTZ(-PP) | 1.05 | 3.27 | 1.62 | 6.37 | |
Be@Sn10 [ (616)] | B3LYP/cc-pVTZ(-PP) | 2.674, 3.164 | 2.71 | 3.43 | 3.37 | 6.62 |
B@Sn10 [ (616)] | B3LYP/cc-pVTZ(-PP) | 1.15 | 3.45 | 3.59 | 5.49 |
All clustersadopt D4d point group symmetry, except for B@Sn10 which has onlyC1 symmetry. For M–Sn bond lengths, the first R value is between M and Sn atoms of Sn8 squareantiprism and the second R value is between M andcapped Sn atoms along the C4 axis.
6.2.2. Endohedrally Doped Sn12 Cages
Cluster | Method | R (Å) | EHL (eV) | Eb (eV) | Eem (eV) | μt (μB) |
---|---|---|---|---|---|---|
Be@Sn12 [ (67)] | PW91/planewave | 2.98 | 1.97 | 2.98 | 4.62 | 0 |
Mg@Sn12 [ (67)] | PW91/planewave | 3.05 | 2.00 | 2.86 | 3.05 | 0 |
Ca@Sn12 [ (67)] | PW91/planewave | 3.13 | 1.92 | 2.81 | 2.38 | 0 |
Mn@Sn12 [ (67)] | PW91/planewave | 3.01 | 1.15 | 2.96 | 4.36 | 5 |
Zn@Sn12 [ (67)] | PW91/planewave | 3.02 | 1.96 | 2.82 | 2.57 | 0 |
Cd@Sn12 [ (67)] | PW91/planewave | 3.06 | 1.94 | 2.77 | 1.87 | 0 |
[Pd@Sn12]2– [ (617)] | B3LYP/def-TZVPP | 2.49 | 4.07 | 0 | ||
[Pt@Sn12]2– [ (617)] | B3LYP/def-TZVPP | 2.43 | 5.76 | 0 | ||
Pd@Bi2Sn10 [ (617)] | B3LYP/def-TZVPP | 2.29 | 4.22 | 0 | ||
Pt@Bi2Sn10 [ (617)] | B3LYP/def-TZVPP | 2.25 | 5.95 | 0 | ||
Mn@Sn12 [ (618)] | MPWB1K/SKBJ | 3.03 | 5 | |||
Mn@Sn12 [ (619)] | PW91/planewave | 3.05 | 1.12 | 5 | ||
Ti@Sn12 [ (620)] | BLYP/DNP | 0.57 | 2.55 | 4.47 | 2 | |
V@Sn12 [ (620)] | BLYP/DNP | 0.58 | 2.57 | 4.78 | 3 | |
Cr@Sn12 [ (620)] | BLYP/DNP | 0.05 | 2.41 | 3.35 | 4 | |
Mn@Sn12 [ (620)] | BLYP/DNP | 1.08 | 2.43 | 3.59 | 5 | |
Fe@Sn12 [ (620)] | BLYP/DNP | 0.20 | 2.52 | 4.01 | 4 | |
Co@Sn12 [ (620)] | BLYP/DNP | 0.43 | 2.58 | 4.35 | 3 | |
Ni@Sn12 [ (620)] | BLYP/DNP | 0.22 | 2.59 | 4.11 | 2 | |
Pu@Sn12 [ (621)] | B3LYP/TZVP | 3.22 | 1.97 | 2.01 | 0 | |
Zn@Sn12 [ (615)] | B3LYP/LanL2DZ | 2.74 | 2.50 | 2.12 | 0 | |
Mn@Sn12 [ (590)] | BPW91/LanL2DZ | 3.08 | 1.08 | 2.64 | 6.89 | 5 |
Tc@Sn12 [ (590)] | BPW91/LanL2DZ | 3.05 | 0.54 | 2.75 | 9.17 | 5 |
Re@Sn12 [ (590)] | BPW91/LanL2DZ | 3.04 | 0.52 | 2.76 | 8.16 | 5 |
Zn@Sn12 [ (590)] | BPW91/LanL2DZ | 3.10 | 1.97 | 2.40 | 3.94 | 0 |
Cd@Sn12 [ (590)] | BPW91/LanL2DZ | 3.16 | 1.95 | 2.34 | 3.01 | 0 |
Hg@Sn12 [ (590)] | BPW91/LanL2DZ | 3.18 | 1.93 | 2.26 | 1.85 | 0 |
[Lr@Sn12]+ [ (622)] | PBE/def-TZVP | 3.21 | 1.62 | 2.79 | 0 | |
[Lu@Sn12]+ [ (622)] | PBE/def-TZVP | 3.18 | 1.70 | 2.95 | 0 | |
[La@Sn12]+ [ (622)] | PBE/def-TZVP | 3.29 | 1.06 | 2.31 | 0 | |
[Ac@Sn12]+ [ (622)] | PBE/def-TZVP | 3.34 | 1.02 | 2.11 | 0 |
Most clusters adopt Ih point group symmetry except for Pd@Bi2Sn10 and Pt@Bi2Sn10.
6.3. Doped Lead Cages
6.3.1. Endohedrally Doped Pb10 Cages
Cluster | Method | R (Å) | EHL (eV) | Eb (eV) | Eem (eV) | VIP (eV) |
---|---|---|---|---|---|---|
Cu@Pb10 [ (563)] | B3LYP/LanL2DZ | 2.864, 3.093 | 2.43 | 3.56 | 5.93 | |
Ag@Pb10 [ (563)] | B3LYP/LanL2DZ | 2.931, 3.117 | 2.33 | 2.47 | 5.84 | |
Au@Pb10 [ (563)] | B3LYP/LanL2DZ | 2.948, 3.131 | 2.43 | 3.53 | 5.72 | |
[Cu@Pb10]− [ (563)] | B3LYP/LanL2DZ | 2.819, 3.314 | 2.58 | 2.61 | 5.53 | 2.97 |
[Ag@Pb10]− [ (563)] | B3LYP/LanL2DZ | 2.892, 3.320 | 2.39 | 2.49 | 4.19 | 2.85 |
[Au@Pb10]− [ (563)] | B3LYP/LanL2DZ | 2.908, 3.346 | 2.26 | 2.49 | 4.17 | 2.75 |
[Cu@Pb10]+ [ (564)] | B3LYP/LanL2DZ | 2.899, 2.914 | 1.80 | 2.36 | ||
[Ag@Pb10]+ [ (564)] | B3LYP/LanL2DZ | 2.969, 2.984 | 1.70 | 2.25 | ||
[Au@Pb10]+ [ (564)] | B3LYP/LanL2DZ | 2.985, 2.983 | 1.80 | 2.50 | ||
[Al@Pb10]+ [ (637)] | B3LYP/aug-cc-pVDZ(-PP) | 2.74 | 4.94 | |||
Al@Pb10 [ (637)] | B3LYP/aug-cc-pVDZ(-PP) | 1.55 | 4.03 | 5.09 | ||
C@Pb10 [ (636)] | PBE/planewave | 2.75 | 0.88 | 2.04 | ||
Al@Pb10 [ (636)] | PBE/planewave | 2.97 | 0.18 | 1.90 | ||
Mg@Pb10 [ (636)] | PBE/planewave | 2.90 | 1.79 | 1.77 | ||
Fe@Pb10 [ (638)] | PBE/DNP | 0.76 | 4.31 | |||
Co@Pb10 [ (638)] | PBE/DNP | 0.79 | 4.48 | |||
Ni@Pb10 [ (638)] | PBE/DNP | 0.83 | 5.54 |
All the clusters adopt D4d point group symmetry. For M–Pb bond lengths, the first R value is between M and Pb atoms of Pb8 square antiprism while the second R value is between M and capped Pb atoms along the C4 axis.
6.3.2. Endohedrally Doped Pb12 Cages
Cluster | Method | R (Å) | EHL (eV) | Eb (eV) | Eem (eV) | VIP (eV) |
---|---|---|---|---|---|---|
[B@Pb12]+ [ (644)] | B3LYP/aug-cc-pVDZ(-PP) | 3.13 | 2.06 | 6.70 | ||
[Al@Pb12]+[ (644)] | B3LYP/aug-cc-pVDZ(-PP) | 3.19 | 3.13 | 6.59 | ||
[Ga@Pb12]+[ (644)] | B3LYP/aug-cc-pVDZ(-PP) | 3.19 | 2.69 | 6.03 | ||
[In@Pb12]+ [ (644)] | B3LYP/aug-cc-pVDZ(-PP) | 3.24 | 3.04 | 5.54 | ||
[Tl@Pb12]+ [ (644)] | B3LYP/aug-cc-pVDZ(-PP) | 3.25 | 2.59 | 4.74 | ||
[Al@Pb12]+ [ (637)] | B3LYP/aug-cc-pVDZ(-PP) | 3.13 | 5.97 | |||
Al@Pb12 [ (637)] | B3LYP/aug-cc-pVDZ(-PP) | 1.06 | 4.26 | 4.32 | ||
Pu@Pb12 [ (621)] | B3LYP/TZVP | 3.33 | 1.93 | 2.06 | ||
Yb@Pb12 [ (132)] | PBE/TZ2P | 3.28 | 0.80 | 1.54 | ||
[Am@Pb12]+ [ (132)] | PBE/TZ2P | 3.35 | 2.45 | 3.01 | ||
C@Pb12 [ (641)] | PBE/planewave | 3.07 | 2.00 | 2.04 | 5.29 | |
Mg@Pb12 [ (641)] | PBE/planewave | 3.16 | 2.30 | 1.89 | 3.33 | |
Al@Pb12 [ (641)] | PBE/planewave | 3.00 | 0.37 | 1.93 | 3.77 | |
In@Pb12 [ (636)] | PBE/planewave | 3.20 | 0.40 | 1.89 | 3.27 | |
Sc@Pb12 [ (642)] | PBE/DNP | 0.24 | 2.68 | 5.97 | ||
Ti@Pb12 [ (642)] | PBE/DNP | 0.63 | 2.79 | 6.11 | ||
V@Pb12 [ (642)] | PBE/DNP | 0.53 | 2.82 | 5.86 | ||
Cr@Pb12 [ (642)] | PBE/DNP | 0.06 | 2.62 | 4.73 | ||
Mn@Pb12 [ (642)] | PBE/DNP | 1.25 | 2.68 | 5.43 | ||
Fe@Pb12 [ (642)] | PBE/DNP | 0.20 | 2.74 | 5.33 | ||
Co@Pb12 [ (642)] | PBE/DNP | 0.52 | 2.80 | 6.14 | ||
Ni@Pb12 [ (642)] | PBE/DNP | 0.31 | 2.81 | 5.77 | ||
[Lr@Pb12]+ [ (622)] | PBE/def-TZVP | 3.30 | 1.81 | 2.86 | 0 | |
[Lu@Pb12]+ [ (622)] | PBE/def-TZVP | 3.28 | 1.87 | 2.92 | 0 | |
[La@Pb12]+ [ (622)] | PBE/def-TZVP | 3.38 | 1.26 | 2.41 | 0 | |
[Ac@Pb12]+ [ (622)] | PBE/def-TZVP | 3.43 | 1.22 | 2.22 | 0 |
All clusters adopt an icosahedral structure, either symmetric or possibly with Jahn–Teller distortion.
6.4. Endohedral Zintl Clusters in Crystalline Phases
Cluster | Compound | M–E (Å) | E–E (Å) | Struc. | Ref. |
---|---|---|---|---|---|
[Co@Ge9]5– | K5Co1.2Ge9 | 2.331–2.374 | 2.683–2.811 | (a) | (645) |
[Ni@Ge9]3– | [K(2,2,2-crypt)]3{[Ni@(Ge9Ni-en)]0.735([Ni@Ge9]·en)0.265}(en) | (a) | (91) | ||
[Fe@Ge10]3– | [K(2,2,2-crypt)]3[Fe@Ge10](en)2 | 2.509–2.535 | 2.526–2.622 | (c) | (541) |
[Co@Ge10]3– | [K(2,2,2-crypt)]4[Co@Ge10][Co(C8H12)2](tol) | 2.479–2.523 | 2.502–2.622 | (c) | (542) |
[Ru@Ge12]3– | [K(2,2,2-crypt)]3[Ru@Ge12](py)4 | 2.651–2.771 | 2.442–2.601 | (g) | (543) |
[Co@Ge12]3– | [K(2,2,2-crypt)]3[CoGe12]0.76[CoGe10]0.24(en) | 2.479–2.781 | 2.569–3.022 | (f) | (592) |
α-[Co2@Ge16]4– | [K(2,2,2-crypt)]4[Co2@Ge16](en)b | 2.519–2.627 | 2.445–2.592 | (h) | (96) |
β-[Co2@Ge16]4– | [K(2,2,2-crypt)]4[Co2@Ge16](en)b | 2.480–2.654 | 2.556–3.210 | (i) | (96) |
[Pd2@Ge18]4– | [K(2,2,2-crypt)]4[Pd2@Ge18](tol)2 | 2.605–2.646 | 2.657–2.965 | (k) | (540) |
[Co@Sn9]5– | K4Ru3Sn7 | 2.641–2.700 | 3.051–3.141 | (a) | (645) |
[Co@Sn9]5– | K12.92Co0.95Sn17 | 2.563–2.670 | 2.943–3.743 | (a) | (93) |
[Co@Sn9]5– | K12.92Co0.95Sn17 | 2.581–2.680 | 2.943–3.743 | (b) | (93) |
[Co@Sn9]5– | K13CoSn16.9 | 2.583–2.680 | 2.963–3.079 | (b) | (646) |
[Co@Sn9]5– | K4.79Co0.79Sn9 | 2.518–2.702 | 2.957–3.750 | (b) | (92) |
[Ni@Sn9]4– | K12.92Co0.95Sn17 | 2.563–2.755 | 2.943–3.743 | (a) | (93) |
[Ni@Sn9]4– | K12.92Co0.95Sn17 | 2.563–2.755 | 2.943–3.743 | (b) | (93) |
[Ni@Sn9]4– | [K(2,2,2-crypt)]6[Ni@Sn9]2(en)3(tol) | 2.562–2.743 | 2.915–3.451 | (a) | (647) |
[Ni@Sn9]4– | K[K(18-crown-6)]3[Ni@Sn9](benzene)3 | 2.521–2.738 | 2.953–3.436 | (a) | (648) |
[Cu@Sn9]3– | [K(2,2,2-crypt)]3[Cu@Sn9](dmf)2 | 2.611–2.700 | 3.052–3.097 | (a) | (94) |
[Cu@Sn9]3– | [K([18]crown-6)]2[K([18]crown-6)(MesH)(NH3)][Cu@Sn9](thf) | 2.599–2.697 | 3.021–3.143 | (b) | (649) |
[Fe@Sn10]3– | [K(2,2,2-crypt)]3[Fe@Sn10](py)4 | 2.578–2.808 | 2.703–3.282 | (d) | (652) |
[Rh@Sn10]3– | [K(2,2,2-crypt)]3[Rh@Sn10](en)2 | 2.670–2.887 | 2.712–3.342 | (e) | (614) |
[Rh@Sn12]3– | [K(2,2,2-crypt)]3[Rh@Sn12](tol)2 | 2.878–2.950 | 3.041–3.129 | (f) | (614) |
[Ir@Sn12]3– | [K(2,2,2-crypt)]3[Ir@Sn12](tol) | 2.883–2.941 | 3.025–3.100 | (f) | (623) |
[Pt2@Sn17]4– | [K(2,2,2-crypt)]3[Pt2@Sn17](en)3 | 2.672–2.815 | 2.958–3.460 | (j) | (657) |
[Pd2@Sn18]4– | [K(2,2,2-crypt)]4[Pd2@Sn18](en)3 | 2.857–2.917 | 3.012–3.145 | (k) | (97) |
[Pd2@Sn18]4– | [K(2,2,2-crypt)]4[Pd2@Sn18](en)3 | 2.849–2.883 | 3.003–3.393 | (k) | (98) |
[Rh3@Sn24]5– | [K(2,2,2-crypt)]5[Rh3@Sn24](dmf)2(tol) | 2.657–3.059 | 2.967–3.190 | (l) | (614) |
[Cu@Pb9]3– | [K(2,2,2-crypt)]3[Cu@Pb9](dmf)2 | 2.710–2.802 | 3.163–3.224 | (a) | (94) |
[Ni@Pb10]2– | [K(2,2,2-crypt)]2[Ni@Pb10] | 2.722, 3.210 | 3.094–3.405 | (e) | (650) |
[Ni@Pb10]2– | [K(2,2,2-crypt)]2[Ni@Pb10] | 2.716–3.210 | 3.103–3.445 | (e) | (651) |
[Ni@Pb12]2– | [K(2,2,2-crypt)]2[Ni@Pb12](en) | 2.889–3.113 | 2.864–3.292 | (f) | (651) |
[Pd@Pb12]2– | [K(2,2,2-crypt)]2[Pd@Pb12](en) | 2.921–3.145 | 3.109–3.269 | (f) | (651) |
[Pt@Pb12]2– | [K(2,2,2-crypt)]2[Pt@Pb12] | 3.055–3.061 | 3.188–3.244 | (f) | (651) |
[Pt@Pb12]2– | [K(2,2,2-crypt)]2[Pt@Pb12] | 3.205–3.223 | 3.058 | (f) | (653) |
[Mn@Pb12]3– | [K(2,2,2-crypt)]3[Mn@Pb12](en)1.5 | 2.869–3.308 | 3.078–3.426 | (f) | (655) |
[Rh@Pb12]3– | [K([18]crown-6)]3[Rh@Pb12](en)2 | 2.984–3.028 | 3.133–3.199 | (f) | (654) |
[Au@Pb12]3– | [K(2,2,2-crypt)]3[Au@Pb12](py)2 | 2.840–3.093 | 3.108–3.257 | (f) | (656) |
M = transition metal; E = Ge, Sn, Pb; 2,2,2-crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane; en = ethylenediamine; py = pyridine; tol = toluene; dmf = dimethylformamide; 18-Crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane; MesH = mesitylene; thf = tetrahydrofuran.
In this compound, α-[Co2@Ge16]4– and β-[Co2@Ge16]4– clusters coexist with 10% occupancy and 90% occupancy, respectively.
n | Skeleton geometry | TVE | Zintl cluster |
---|---|---|---|
9 | capped square antiprism (nido-deltahedron) | 4 × 9 + 4 = 40 | [Co@Sn9]5– [ (92)- (93), (646)], [Ni@Sn9]4– [ (93)], [Cu@Sn9]3– [ (649)] |
10 | bicapped square antiprism (closo-deltahedron) | 4 × 10 + 2 = 42 | [Rh@Sn10]3– [ (614)], [Ni@Pb10]2– [ (650)- (651)] |
10 | pentagonal prism structure (3-connect polyhedron) | 5 × 10 = 50 | [Fe@Ge10]3– [ (541)], [Co@Ge10]3– [ (542)] |
12 | icosahedron (closo-deltahedron) | 4 × 12 + 2 = 50 | [Co@Ge12]3– [ (592)], [Rh@Sn12]3– [ (614)], [Ir@Sn12]3– [ (623)], [Ni@Pb12]2– [ (650)- (651)], [Pd@Pb12]2– [ (651)], [Pt@Pb12]2– [ (651)- (653)], [Rh@Pb12]3– [ (654)], [Au@Pb12]3– [ (656)] |
12 | D2h cage (3-connect polyhedron) | 5 × 12 = 60 | [Ru@Ge12]3– [ (543)] |
16 | D2h prolate cage (3-connect polyhedron) | 5 × 16 = 80 | [Co2@Ge16]4– [ (95)- (96)] |
18 | D3d prolate cage (closo-deltahedron) | 4 × 18 + 4 = 76 | [Pd2@Ge18]4– [ (540)], [Pd2@Sn18]4– [ (97)- (98)] |
Here n is the number of E atoms, skeleton geometry is only for E atoms (polyhedral type is given in the parentheses), TVE gives the total number of valence electrons calculated by the Wade–Mingos rules.
7. Endohedrally Doped Cages of Group 11 Elements
7.1. Doped Au Cages
7.1.1. Endohedrally Doped Au12 Cages
7.1.2. Endohedrally Doped Au14 and Au15 Cages
7.1.3. Endohedrally Doped Au16-18 Cages
System | Method | Author (year) |
---|---|---|
M@Au16 (M = Mg, Ca, Sr) | BP86/SDD+2f, LanL2DZ | Gao et al. (2006) (640) |
M@Au17 (M = Na, K) | BP86/SDD+2f, LanL2DZ | Gao et al. (2006) (640) |
M@Au16 (M = Si, Al) | PBE/planewave | Walter et al. (2006) (709) |
[M@Au16]− (M = Cu, Ag, Li, Na, K) | PBE/DNP | Fa et al. (2008) (713) |
[C@Au16]− | PW91/DNP | Fa et al. (2008) (714) |
[Cu@Aun]− (n = 16, 17) | PBE/LanL2DZ | Zorriasatein et al. (2008) (722) |
Mn@Au16 | PW91/DNP | M. Zhang et al. (2012) (696) |
[Gd@Au16]0/+ | PW91/planewave | Shinde et al. (2012) (703) |
Eu@Au16 | PW91/planewave | Shinde et al. (2012) (703) |
[M@Au16]−/0 (M = Cr, Mn) | PBE/SDD+2f, 6-311+G(d) | H. Q. Wang et al. (2013) (715) |
[M@Au16]− (M = B, Al, Ga, In) | PBE/DNP | Tang et al. (2013) (716) |
[M@Au16]−/0 (M = Sc, Ti, V) | PBE/LanL2DZ | H. F. Li et al. (2014) (717) |
M@Au17 (M = Cu, Ag, Li, Na, K) | PBE/DNP | Tang et al. (2014) (720) |
M@Au18 (M = Na, K, Mg, Ca, Al, Ga) | PBE/LanL2DZ | Manzoor et al. (2016) (721) |
[Rh@Au16]−/0 | PBE/planewave | J. X. Liu et al. (2017) (718) |
[M@Au16]−/0 (M = Mo, Tc) | PBE/SDD+2f, ECP28MWB | H. F. Li et al. (2018) (719) |
Here M denotes the endohedral atom, n is the number of Au atoms, and q is the charge on the cluster.
7.1.4. Endohedrally Doped Au32 Cages
7.2. Doped Ag Cages
7.3. Doped Cu Cages
7.4. Reactivity and SERS of Endohedral Coinage Metal Cages
8. Endohedrally Doped Cages of Compounds
8.1. Endohedral BN Cages
Cluster | Hf (eV) | EHL (eV) | μM (μB) | Q (e) | B–N bond length (Å) | Symmetry |
---|---|---|---|---|---|---|
Sc@B24N24 | –2.047 | 0.573 | 1.034 | 0.663 | 1.471 | S8 |
Ti@B24N24 | 0.544 | 1.181 | 2.161 | 0.871 | 1.445 | C4 |
V@B24N24 | –2.183 | 0.359 | 3.069 | 0.822 | 1.470 | S8 |
Cr@B24N24 | –1.364 | 1.564 | 3.886 | 0.647 | 1.465 | S8 |
Mn@B24N24 | –2.015 | 0.784 | 4.540 | 0.403 | 1.470 | S8 |
Fe@B24N24 | –2.807 | 1.168 | 2.937 | 0.611 | 1.465 | C1 |
Co@B24N24 | –3.218 | 0.990 | 1.432 | 0.685 | 1.466 | S8 |
Ni@B24N24 | –2.861 | 0.433 | 0.000 | 0.701 | 1.469 | S8 |
Cu@B24N24 | –2.469 | 0.694 | 0.000 | 0.787 | 1.470 | S8 |
Zn@B24N24 | –1.737 | 3.551 | 0.000 | 0.851 | 1.469 | S8 |
Y@B24N24 | –2.019 | 0.404 | 0.700 | 0.968 | 1.473 | C1 |
Zr@B24N24 | 0.354 | 0.891 | 0.000 | 1.092 | 1.447 | C4 |
Nb@B24N24 | –1.467 | 0.901 | 1.006 | 1.010 | 1.470 | C4 |
Mo@B24N24 | –0.359 | 0.475 | 1.899 | 0.843 | 1.470 | S8 |
Tc@B24N24 | –2.236 | 0.810 | 2.966 | 0.611 | 1.470 | S8 |
Ru@B24N24 | –3.112 | 1.225 | 1.994 | 0.850 | 1.471 | C4 |
Rh@B24N24 | –3.264 | 0.426 | 0.962 | 0.834 | 1.469 | C4 |
Pd@B24N24 | –2.648 | 2.554 | 0.000 | 0.886 | 1.469 | S8 |
Ag@B24N24 | 1.452 | 0.597 | 0.000 | 0.929 | 1.444 | C4 |
Cd@B24N24 | 2.362 | 3.214 | 0.000 | 0.962 | 1.453 | C4 |
M@B36N36 | M4@B36N36 | |||
---|---|---|---|---|
M | Magnetic Moment (μB) | Embedding energy (eV) | Magnetic Moment (μB) | Embedding energy (eV) |
Ti | 4 (4) | 1.02 | 2 (4) | 0.31 |
V | 5 (5) | 0.40 | 0 (0) | 0.51 |
Cr | 6 (6) | 0.06 | 8 (0) | 3.79 |
Mn | 5 (5) | –0.10 | 10 (20) | 2.68 |
Fe | 4 (4) | 0.20 | 10 (14) | 1.12 |
Co | 3 (3) | 0.64 | 6 (10) | 1.57 |
Ni | 0 (2) | 0.78 | 2 (4) | 1.73 |
Cu | 1 (1) | 0.12 | 0 (0) | –0.59 |
The numbers in parentheses are magnetic moments of free M atom or M4 cluster.
8.2. Endohedral Doping of Cages of II–VI Semiconductors
M | XY | n | Method | Author (year) |
---|---|---|---|---|
Li | ZnS | 4 | B3LYP/6-311+G(d) | Matxain et al. (2007) (799) |
Na, K, Na+, K+ | ZnS | 9, 12, 13, 15, 16 | B3LYP/6-311+G(d) | Matxain et al. (2007) (799) |
Cl, Br, Cl–, Br– | ZnS | 9, 12, 15, 16 | B3LYP/6-311+G(d) | Matxain et al. (2007) (799) |
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu | ZnS | 12, 16 | B3LYP/SKBJ | Matxain et al. (2008) (801) |
Cr | ZnS | 12 | PBE/DNP | Chen et al. (2010) (804) |
Mn | ZnS | 12 | PBE/DNP | Chen et al. (2010) (805) |
Fe, Co, Ni | ZnS | 12 | PBE/DNP | Chen et al. (2011) (806) |
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu | ZnS | 12, 16 | B3LYP/SKBJ | Jimenez-Izal et al. (2011) (802) |
Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd | ZnS | 12, 16 | B3LYP/SKBJ | Jimenez-Izal et al. (2013) (803) |
Ti, V, Cr, Mn, Fe, Co, Ni | ZnS | 6, 12 | PBE/TZ2P | Poggio et al. (2015) (800) |
Mn | ZnSe | 6, 7, 8, 9, 10, 11, 12, 13 | BLYP/DNP | D. Zhang et al. (2011) (807) |
Cr | ZnTe | 12 | PBE/planewave | Yadav et al. (2009) (808) |
Cr | CdS | 12 | BLYP/DNP | Ghosh et al. (2010) (809) |
K, K+, Cl, Br, Cl–, Br– | CdS | 9, 12, 15, 16 | B3LYP/6-311+G(d) | Jimenez-Izal et al. (2010) (810) |
Ti, V, Cr, Mn, Fe, Co, Ni | CdS | 6, 12 | PBE/TZ2P | Poggio et al. (2015) (811) |
Here M denotes the endohedral atom or ion while n is the number of X or Y atoms.
8.3. Endohedrally Doped Group 13 and Group 15 (III–V Semiconductors) Compound Cages
M | XY | n | Method | Author (year) |
---|---|---|---|---|
Mn, Fe | GaAs | 7, 8, 9, 10, 11, 12 | PBE/DNP | J. Wang et al. (2008) (818) |
Mn | GaN | 12 | PBE/DNP | Lu et al. (2013) (819) |
Fe | GaN | 12 | PBE/DNP | Lu et al. (2013) (820) |
Ti | InP | 7, 8, 9, 10, 11, 12 | PBE/TZ2P | Longo et al. (2009) (821) |
Cr, Mn, Fe, Co | InP | 10 | PBE/TZ2P | Longo et al. (2009) (821) |
Mn, Fe, Co | InSb | 7, 8, 9, 10, 11, 12, 14, 16 | PBE/DNP | Ding et al. (2011) (822) |
Here XY represents a compound of groups 13 and 15 (III–V compound semiconductor), M denotes the endohedral atom, and n is the number of X or Y atoms.
8.4. Endohedral Metal Oxide Cages
M | Cage cluster | Method | Author (year) |
---|---|---|---|
Mn | Zn12O12 | PW91/DNP | H. Liu et al. (2006) (825) |
Cr | Zn12O12 | PBE/planewave | H. Liu et al. (2018) (826) |
Li, Na, K, Rb | Zn12O12 | B3LYP/LANL2DZ | Baei et al. (2013) (827) |
Li, Na, K | Be12O12 | B3LYP/6-311+G(d) | Shakerzdeh et al. (2015) (829) |
Li, Na, K | Mg12O12 | B3LYP/6-311+G(d) | Shakerzdeh et al. (2015) (829) |
Here M denotes the endohedral atom.
8.5. Endohedral Cages of Group 14-15 and 14-14 Compounds
9. Multilayer Matryoshka Cages and Core-Shell Structures
Cluster | Method | R1 (Å) | R2 (Å) | EHL (eV) | Eb (eV) |
---|---|---|---|---|---|
[As@Ni12@As20]3– (99) | XRD | 2.558 | 2.396 | ||
[As@Ni12@As20]3– (850,851) | PBE/Gaussian basis | 2.59 | 2.44 | 1.45 | |
[As@Ni12@As20]3– (852) | PW91/Planewave | 2.65 | 2.43 | 1.44 | 5.21 |
[As@Ni12@As20]3– (853,854) | BP86/LANL2DZ | 2.579 | 2.488 | 1.41 | 3.45 |
[As@Ni12@As20]3– (859) | PBE/TZ2P | 2.591 | 2.418 | ||
[Br@Ni12@As20]− (853) | BP86/LANL2DZ | 2.656 | 2.792 | 1.07 | 3.37 |
[Sb@Pd12@Sb20]3– (101) | XRD, analytic density functional/DZVP | 2.856 | 2.713 | 1.33 | |
[Sb@Pd12@Sb20]3– (102) | XRD, B3LYP | 2.850 | 2.709 | 2.24 | |
[Sb@Pd12@Sb20]3– (852) | PW91/Planewave | 3.87 | 2.69 | 1.41 | 4.49 |
[Sn@Cu12@Sn20]12– (Na) (100) | XRD | 2.631 | 2.766 | ||
[Sn@Cu12@Sn20]12– (K) (100) | XRD, B3LYP/(PP-)Def2-TZVP | 2.625 | 2.760 | 1.34 | |
[Sn@Cu12@Sn20]12– (859,860) | PBE/TZ2P | 2.697 | 2.865 | ||
Ge@Zn12@Ge20 (854) | BP86/LANL2DZ | 2.802 | 2.813 | 1.39 | 2.01 |
Sn@Mg12@Sn20 (855) | PW91/DND | 2.996 | 3.029 | 1.38 | 2.79 |
Sn@Zn12@Sn20 (855) | PW91/DND | 2.827 | 2.907 | 1.47 | 3.43 |
Sn@Cd12@Sn20 (855) | PW91/DND | 3.128 | 3.034 | 1.29 | 2.60 |
Sn@Mn12@Sn20 (855) | PW91/DND | 2.569 | 2.870 | 0.38 | |
Pb@Mg12@Pb20 (855) | PW91/DND | 3.073 | 3.140 | 1.50 | 2.52 |
Pb@Zn12@Pb20 (855) | PW91/DND | 2.919 | 3.033 | 1.54 | 2.97 |
Pb@Cd12@Pb20 (855) | PW91/DND | 3.187 | 3.147 | 1.27 | 2.28 |
Pb@Mn12@Pb20 (855) | PW91/DND | 2.629 | 3.016 | 0.61 |
For some cases, DFT single-point calculations were performed using cluster structure from experimental XRD data.
10. Assemblies of Endohedrally Doped Cage Clusters
10.1. Dimers and Aggregates of Endohedrally Doped Cages
10.2. From Endohedrally Doped Clusters to Metal Filled One-Dimensional Nanotubes or Nanowires
10.3. Two-Dimensional Assemblies of Endohedrally Doped Cage Clusters
10.4. Three-Dimensional Crystals Assembled from Endohedrally Doped Cage Clusters
a (Å) | c (Å) | Ec (eV) | B (GPa) | Eg (eV) | EHL (eV) | |
---|---|---|---|---|---|---|
Ti@Si16 | 8.75 | 14.36 | 0.20 | 1.25 | 1.3 | 2.3 |
Zr@Si16 | 9.05 | 14.79 | 0.14 | 0.90 | 1.6 | 2.4 |
Hf@Si16 | 8.96 | 14.89 | 0.15 | 0.97 | 1.6 | 2.5 |
10.5. Self-Assembled Crystals of Ligated Endohedrally Metal-Atom-Doped Nanoclusters
11. Perspective
(1) | Despite many endohedrally doped clusters already discovered, as mentioned above, there are still numerous possibilities to search for such clusters with high stability and exotic physical and chemical properties that are awaiting exploration, considering that a very large number of combinations of elements and spatial arrangements of atoms are possible. In this regard, global search methods based on ab initio calculations could be an exciting tool in theoretical design of novel endohedrally doped clusters. |
||||
(2) | While already quite a few interesting endohedrally doped clusters with high stability have been predicted from theory, only a small number of them have been generated and well characterized in the laboratory. Although this progress on some clusters is very encouraging, there are many interesting systems such as metal doped boron cages Mo@B24 awaiting realization. Also, many small carbon fullerenes with endohedral doping have been predicted, and it would be interesting to carry out experiments on these systems as there could be a good possibility for assembling them. In general, in order to realize new materials and device applications, one must be able to produce clusters with a specific size and composition in macroscopic amount. A good example is the mass production of C60 fullerene using electric arc evaporation of graphite that fueled much progress, and we hope for interesting developments for the large-scale production of a variety of endohedral clusters in the future. |
||||
(3) | The current theoretical and experimental studies mainly focus on the fundamental properties, and much less efforts have been devoted to the potential applications of endohedrally doped clusters by exploiting their advantageous characteristics. As an example, there is an upsurge in single atom catalysis, and it would be interesting to explore how to utilize the endohedrally doped clusters such as those of transition metals and coinage metals with tunable surface activity to develop highly efficient catalysts. With proper selection of dopant atoms and host caged clusters, novel nonmetal catalysts based on endohedrally doped clusters may also be designed. Furthermore, the endohedral clusters may have novel temperature-dependent properties, which are still largely unexplored. |
||||
(4) | There have been a few successful examples of magnetic superatoms with large magnetic moments, moderate HOMO–LUMO gap, and high stability, such as Mn@Ge12, Mn@Sn12, Eu@Si20, and Gd@Au15. These clusters may offer possibilities to develop new magnetic materials. More such species are sought after, and further research would be desirable. Moreover, the endohedrally doped clusters have tunable electronic gap, and for many of them the gap amplitudes are in the visible light range, allowing them to harvest the majority of the spectrum of the sunlight. These features should be taken advantage of for optoelectronic applications. Another question is if such clusters could be candidates for the ultimate molecular level devices. Experimental exploration of cluster-based devices is still in its embryonic stage, although there have been a few theoretical designs of cluster-based devices for spintronic, nanoelectronics, and optoelectronics. Certainly, further work on cluster-based devices from both theoretical and experimental sides is needed. |
||||
(5) | In practical applications, the size-selected gas phase clusters have to be deposited on a substrate. For such supported clusters, the cluster–substrate interaction would be a crucial topic that would be worth further investigation. A carefully chosen substrate should not only support and anchor the clusters, but also avoid their aggregation and further growth, and result in optimal functional properties by making use of the synergic effect. Recent work on 2D assemblies of Ta@Si16 fullerene clusters on C60 covered TiO2 support is promising, and further work is expected in the future so that we could have guidelines for 1D, 2D, and 3D assemblies. For this, as we have discussed in Section 10, cluster–cluster interaction in dimers of many endohedral cage clusters is still rather strong (binding energy larger than 1.0 eV), but there are a few exceptions such as FK polyhedral clusters of Ti@Si16 and Ti@Ge16. More such clusters with weak intercluster interaction should be searched and explored for the development of cluster-assembled systems in different dimensions, similar to solid C60 and its compounds. Besides, there would be tremendous opportunities for making crystals of ligated clusters. |
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.chemrev.9b00651.
Comparison between the calculated (PBE0/6-311+G(d)) and experimental bond lengths as well as Raman and infrared frequencies of C60 fullerene (Table S1); comparison between the theoretical (PBE0/PAW) and experimental equilibrium lattice constant, cohesive energy, and bulk modulus of B, C, Si, Ge, Al, Au, Ag, Cu crystals (Table S2). Tables S3–S22 give the geometric and electronic properties of endohedral cage clusters from PBE0/6-311+G(d), SDD calculations for M@C28, M@Bn (n = 18–24), M@Si10, M@Si11, M@Si12, M@Si13, M@Si14, M@Si15, M@Si16, M@Si18, 20, M@Ge10, M@Ge11, M@Ge12, M@Ge13, M@Ge14, M@Ge15, M@Ge16, M@Aun (n = 12–17), M@Agn (n = 8–15), and M@Cun (n = 12, 16). (PDF)
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Biographies
Acknowledgments
JZ and SZ would like to acknowledge support by the National Natural Science Foundation of China (91961204, 11974068, 11574040), the Fundamental Research Funds for the Central Universities of China (DUT20LAB110), and the Supercomputing Center of Dalian University of Technology. VK would like to thank all his collaborators for fruitful cooperation that has helped in the development of many ideas and results presented in this review. In particular, he is grateful to Y. Kawazoe and many students and visitors at the Institute for Materials Research at the Tohoku University where many interesting papers were written and all the computational resources of the Center for Computational Materials Science that were so important to carry out the work. VK is also thankful to the Asian Office of the Aerospace Research and Development (AOARD) and International Technology Center-Pacific (ITC-PAC) for their support on different projects that helped to continue to make progress on these systems and all collaborators at the Foundation and Shiv Nadar University (SNU). VK is grateful to N. Sukumar for all the help and cooperation at the SNU. VK also acknowledges the computational resources from the Center for the Development of Advanced Computing (CDAC), Pune and the MAGUS resources at the SNU where some of the work has been carried out. Finally we sincerely thank the reviewers for their great efforts and constructive suggestions that helped us to improve the presentation.
List of Abbreviations
ADE | adiabatic detachment energies |
AEA | adiabatic electron affinity |
AIMD | ab initio molecular dynamics |
AIP | adiabatic ionization potential |
amu | atomic mass unit |
BCC | body centered cubic |
BCT | body centered tetragonal |
BN | boron nitride |
CC | coupled cluster |
DFT | density functional theory |
DOS | density of state |
ECP | effective core potential |
ESI-MS | electrospray ionization mass spectrometry |
EPR | electron paramagnetic resonance |
FCC | face centered cubic |
FK | Frank–Kasper |
FT-ICR | Fourier transform–ion cyclotron resonance |
GA | genetic algorithm |
GGA | generalized gradient approximation |
HCP | hexagonal close packed |
HF | Hartree–Fock |
HOMO | highest occupied molecular orbital |
HREM | high-resolution electron microscopy |
LUMO | lowest unoccupied molecular orbital |
HOPG | highly oriented pyrolytic graphite |
IR-MPD | infrared multiple photon dissociation |
IR-UV2CI | infrared–ultraviolet two-color ionization |
LDA | local density approximation |
LDI-TOF | laser desorption–ionization time-of-flight |
LD-TOF | laser desorption time-of-flight |
MD | molecular dynamics |
L-H | Langmuir–Hinshelwood |
MS | mass spectrometry |
NBO | natural bond orbital |
NICS | nucleus-independent chemical shift |
NMR | nuclear magnetic resonance |
PAW | projector augmented wave |
PEG-DME | poly(ethylene glycol) dimethyl ether |
PES | photoelectron spectrum |
QLMD | quantum Langevin molecular dynamics |
RPA | random-phase approximation |
SC | simple cubic |
SERS | surface-enhanced Raman spectroscopy |
SOC | spin-orbital coupling |
STM/STS | scanning tunneling microscopy and spectroscopy |
TD-DFT | time-dependent density functional theory |
TGA | thermogravimetric analysis |
TS | transition states |
TTP | tricapped-trigonal-prism |
UPS | ultraviolet photoelectron spectroscopy |
VEA | vertical electron affinity |
VIP | vertical ionization potential |
XPS | X-ray photoelectron spectroscopy |
XMCD | X-ray magnetic circular dichroism |
ZORA | zeroth-order approximation |
0D | zero-dimensional |
1D | one-dimensional |
2D | two-dimensional |
3D | three-dimensional |
References
This article references 985 other publications.
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1De Heer, W. A. The physics of simple metal clusters: experimental aspects and simple models. Rev. Mod. Phys. 1993, 65, 611– 676, DOI: 10.1103/RevModPhys.65.611Google Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsVCgu70%253D&md5=ba77ebdb31643f78f19a6183aa62c3deThe physics of simple metal clusters: experimental aspects and simple modelsde Heer, Walt A.Reviews of Modern Physics (1993), 65 (3, Pt. 1), 611-76CODEN: RMPHAT; ISSN:0034-6861.A review with many refs. The study of simple metal clusters has burgeoned in the last decade, motivated by the growing interest in the evolution of phys. properties from the atom to the bulk solid, a progression passing through the domain of at. clusters. On the exptl. side, the rapid development of new techniques for producing the clusters and for probing and detecting them has resulted in a phenomenal increase in the knowledge of these systems. For clusters of the simplest metals (the alkali and noble metals), the electronic structure is dominated by the no. of valence electrons, and the ionic cores are of secondary importance. These electrons are delocalized, and the electronic system exhibits a shell structure that is closely related to the well-known nuclear shell structure. The results from a broad range of expts. are compared with theory. The properties discussed include: behavior of the mass-abundance spectra; polarizabilities; ionization potentials; photoelectron spectra; optical spectra; and fragmentation phenomena.
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2Castleman, A.; Bowen, K. Clusters: Structure, energetics, and dynamics of intermediate states of matter. J. Phys. Chem. 1996, 100, 12911– 12944, DOI: 10.1021/jp961030kGoogle Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xkt1altb0%253D&md5=5d7da2f1be8addb21abe4a461a51e78eClusters: Structure, Energetics, and Dynamics of Intermediate States of MatterCastleman, A. W., Jr.; Bowen, K. H., Jr.Journal of Physical Chemistry (1996), 100 (31), 12911-12944CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)A review with 692 refs.; the field of cluster research can trace its origins back to the mid-nineteenth century when early studies of colloids, aerosols, and nucleation phenomena were reported. The field underwent a resurgence of interest several decades ago when well-defined clusters were obsd. in supersonic expansions that could be investigated using mass spectrometers. The advent of the laser provided a new dimension, enabling detailed spectroscopic observations through the probing of systems of varying size and degree of solvation. Modern interest derives from recognition that interrogating clusters provides a way of studying the energetics and dynamics of intermediate states of matter as cluster systems evolve from the gas toward the condensed state. Herein, we endeavor to highlight some of the significant advances which have been made during the past several decades that have led to a nearly explosive growth of interest in the field of cluster science. Finally, we conclude that the field will continue to expand through interests in basic phenomena, as well as through numerous applications of cluster research to fields ranging from catalysis to the quest for new cluster-assembled materials.
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3Alonso, J. Electronic and atomic structure, and magnetism of transition-metal clusters. Chem. Rev. 2000, 100, 637– 678, DOI: 10.1021/cr980391oGoogle Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXksFyhug%253D%253D&md5=b6242dac72711b7f9674c54bd5899d08Electronic and Atomic Structure, and Magnetism of Transition-Metal ClustersAlonso, J. A.Chemical Reviews (Washington, D. C.) (2000), 100 (2), 637-677CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review is presented with 291 refs. with discussion on noble metal clusters, general bonding properties and electronic structure of clusters of transition metals, thermionic emission from refractory metal clusters, nonmetal-metal transition, icosahedral model of Ni clusters and its relation to reactivity, size and temp. dependence of magnetic moments and their measurement, magnetic shell models, DFT study of magnetic properties of clusters of 3d elements, magnetism in clusters of 4d elements, noncollinear magnetism in iron clusters.
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4Janssens, E.; Neukermans, S.; Lievens, P. Shells of electrons in metal doped simple metal clusters. Curr. Opin. Solid State Mater. Sci. 2004, 8, 185– 193, DOI: 10.1016/j.cossms.2004.09.002Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtlSrsLc%253D&md5=e11690246370b01b65e94b5c77b80ae8Shells of electrons in metal doped simple metal clustersJanssens, Ewald; Neukermans, Sven; Lievens, PeterCurrent Opinion in Solid State & Materials Science (2005), 8 (3-4), 185-193CODEN: COSSFX; ISSN:1359-0286. (Elsevier Ltd.)A review. Recent studies of electronic and structural properties of small doped metal clusters are reviewed. Both theor. and exptl. investigations of size and compn. dependent cluster properties have emphasized the importance of the interplay between geometry and electronic structure. The conceptually simple phenomenol. shell models, which have been used extensively to describe bare simple metal clusters, are extended towards different types of doped cluster species by choosing appropriate ad hoc potentials. More detailed fundamental understanding is gained by investigating the delocalized MOs as computed with ab initio d. functional theory.
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5Baletto, F.; Ferrando, R. Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effects. Rev. Mod. Phys. 2005, 77, 371– 423, DOI: 10.1103/RevModPhys.77.371Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXkvVCmtL0%253D&md5=f0c919972406ca61cf22e8dc64b3dec3Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effectsBaletto, Francesca; Ferrando, RiccardoReviews of Modern Physics (2005), 77 (1), 371-423CODEN: RMPHAT; ISSN:0034-6861. (American Physical Society)A review. The structural properties of free nanoclusters are reviewed. Special attention is paid to the interplay of energetic, thermodn., and kinetic factors in the explanation of cluster structures that are actually obsd. in expts. The review starts with a brief summary of the exptl. methods for the prodn. of free nanoclusters and then considers theor. and simulation issues, always discussed in close connection with the exptl. results. The energetic properties are treated first, along with methods for modeling elementary constituent interactions and for global optimization on the cluster potential-energy surface. After that, a section on cluster thermodn. follows. The discussion includes the anal. of solid-solid structural transitions and of melting, with its size dependence. The last section is devoted to the growth kinetics of free nanoclusters and treats the growth of isolated clusters and their coalescence. Several specific systems are analyzed.
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6Ferrando, R.; Jellinek, J.; Johnston, R. L. Nanoalloys: from theory to applications of alloy clusters and nanoparticles. Chem. Rev. 2008, 108, 845– 910, DOI: 10.1021/cr040090gGoogle Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtVCkt7w%253D&md5=58cba8c4e8af59b6e765a54be5bb1926Nanoalloys: From Theory to Applications of Alloy Clusters and NanoparticlesFerrando, Riccardo; Jellinek, Julius; Johnston, Roy L.Chemical Reviews (Washington, DC, United States) (2008), 108 (3), 845-910CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The topics discussed are: types and structures of nanoalloys (NA), their application, methods for generating NA, exptl. techniques for characterization and modeling potential energy surface of NA. Further topics include: structural optical, and magnetic properties, catalysis of NA, melting, intermixing kinetics, freezing, growth, and coalescence of NA, ternary NA clusters.
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7Jena, P.; Castleman, A., Jr Mass spectrometry and its role in advancing cluster science. Int. J. Mass Spectrom. 2015, 377, 235– 247, DOI: 10.1016/j.ijms.2014.08.033Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVCju73K&md5=9f48dcdcde71c606e100c8cde57c4a12Mass spectrometry and its role in advancing cluster scienceJena, P.; Castleman, A. W.International Journal of Mass Spectrometry (2015), 377 (), 235-247CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)Clusters composed of a few to a few hundred atoms are the ultimate nanoparticles where every atom and every electron count. Over the past 50 years clusters have evolved as a new field of matter intermediate between atoms and bulk. In this retrospective we trace the role mass spectrometry has played in this emerging field with emphasis on how extremely intense mass peaks indicating a high abundance of clusters led to the discovery of magic nos. in alkali metal clusters, the fullerenes in carbon clusters, and "Met-Cars" in transition-metal carbide clusters. Magic nos. in alkali metal clusters in turn helped bridge the gap between two disparate fields, at. physics and nuclear physics. Studies of mass spectra combined with theory and a variety of other exptl. techniques have since led to a fundamental understanding of the structure-property relationships of clusters, thus broadening the scope of cluster science. Clusters not only serve as a bridge between atoms and bulk and between at. and nuclear physics, but also as a bridge across many disciplines. Although this retrospective is focused on at. clusters, briefly discussed is the solvation phenomenon, a subject to which mass spectrometry has and continues to make a large contribution.
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8Zhao, J.; Huang, X.; Jin, P.; Chen, Z. Magnetic properties of atomic clusters and endohedral metallofullerenes. Coord. Chem. Rev. 2015, 289, 315– 340, DOI: 10.1016/j.ccr.2014.12.013Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmvF2lsA%253D%253D&md5=76e70bc6b019cea2517546b26fc74b89Magnetic properties of atomic clusters and endohedral metallofullerenesZhao, Jijun; Huang, Xiaoming; Jin, Peng; Chen, ZhongfangCoordination Chemistry Reviews (2015), 289-290 (), 315-340CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)Magnetic clusters are aggregates of a few to thousands of atoms or mols. that exhibit magnetism. Understanding the evolution of magnetism from individual atom to bulk solid is fundamentally important, and combining different types and no. of atoms would lead to many opportunities in tuning magnetic properties of an alloy cluster. The magnetic behaviors of a cluster can be measured by the Stern-Gerlach deflections or the X-ray magnetic CD spectroscopy in a mol. beam and calcd. by ab initio methods. Herein we present a comprehensive review on the exptl. and theor. progresses on the magnetic properties of the ligand-free gas-phase clusters up to a few hundred atoms, including elemental metal clusters, alloy clusters, metal-doped semiconductor clusters, magnetic superatom clusters. Endohedral metallofullerenes, a special kind of magnetic clusters, are also briefly illustrated.
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9Luo, Z.; Castleman, A., Jr; Khanna, S. N. Reactivity of metal clusters. Chem. Rev. 2016, 116, 14456– 14492, DOI: 10.1021/acs.chemrev.6b00230Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFelu7nE&md5=7f53c625aea3fd14116584bf25c08ca8Reactivity of Metal ClustersLuo, Zhixun; Castleman, A. W.; Khanna, Shiv N.Chemical Reviews (Washington, DC, United States) (2016), 116 (23), 14456-14492CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)We summarize here the research advances on the reactivity of metal clusters. After a simple introduction of apparatuses used for gas-phase cluster reactions, we focus on the reactivity of metal clusters with various polar and nonpolar mols. in the gas phase and illustrate how elementary reactions of metal clusters proceed one-step at a time under a combination of geometric and electronic reorganization. The topics discussed in this study include chem. adsorption, addn. reaction, cleavage of chem. bonds, etching effect, spin effect, the harpoon mechanism, and the complementary active sites (CAS) mechanism, among others. Insights into the reactivity of metal clusters not only facilitate a better understanding of the fundamentals in condensed-phase chem. but also provide a way to dissect the stability and reactivity of monolayer-protected clusters synthesized via wet chem.
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10Claridge, S. A.; Castleman, A., Jr; Khanna, S. N.; Murray, C. B.; Sen, A.; Weiss, P. S. Cluster-assembled materials. ACS Nano 2009, 3, 244– 255, DOI: 10.1021/nn800820eGoogle Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVyksrk%253D&md5=92e6025e94ae3884c8ca7a098859acabCluster-Assembled MaterialsClaridge, Shelley A.; Castleman, A. W., Jr.; Khanna, Shiv N.; Murray, Christopher B.; Sen, Ayusman; Weiss, Paul S.ACS Nano (2009), 3 (2), 244-255CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. Cluster-assembled materials offer the ability to tune component properties, lattice parameters, and thus coupling of phys. properties through the careful selection and assembly of building blocks. Multi-atom clusters have been found to exhibit phys. properties beyond those available from the std. elements in the periodic table; classification of the properties of such clusters effectively enables expansion of the periodic table to a third dimension. Using clusters as superat. building blocks for hierarchically assembled materials allows these properties to be incorporated into designer materials with tailored properties. Cluster-assembled materials are currently being explored and methods developed to control their design and function. Here, we discuss examples of building block syntheses, assembly strategies, and property control achieved to date.
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11Mandal, S.; Reber, A. C.; Qian, M.; Weiss, P. S.; Khanna, S. N.; Sen, A. Controlling the band gap energy of cluster-assembled materials. Acc. Chem. Res. 2013, 46, 2385– 2395, DOI: 10.1021/ar3002975Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXosFygsb0%253D&md5=515458133c6780a86848eff3b34768b1Controlling the Band Gap Energy of Cluster-Assembled MaterialsMandal, Sukhendu; Reber, Arthur C.; Qian, Meichun; Weiss, Paul S.; Khanna, Shiv N.; Sen, AyusmanAccounts of Chemical Research (2013), 46 (11), 2385-2395CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. Cluster-assembled materials combine the nanoscale size and compn.-dependent properties of clusters, which have highly tunable magnetic and electronic properties useful for a great variety of potential technologies. To understand the emergent properties as clusters are assembled into hierarchical materials, the authors synthesized 23 cluster-assembled materials composed of As73--based motifs and different countercations and measured their band gap energies. The band gap energy varies from 1.09 to 2.21 eV. The authors have carried out 1st principles electronic structure studies to identify the phys. mechanisms that enable control of the band gap edges of the cluster assemblies. The choice of counterion has a profound effect on the band gap energy in ionic clusterassemblies. The top of the valence band is localized on the arsenic cluster, while the conduction band edge is located on the alkali metal counterions. Changing the counterion changes the position of the conduction band edge, enabling control of the band gap energy. The authors can also vary the architecture of the ionic solid by incorporating cryptates as counterions, which provide charge but are sepd. from the clusters by bulky ligands. Higher dimensionality typically decreases the band gap energy through band broadening; however band gap energies increased upon moving from zero-dimensional (0D) to two-dimensional (2D) assemblies. This is because internal elec. fields generated by the counterion preferentially stabilize the adjacent lone pair orbitals that mark the top of the valence band. Thus, the choice of the counterion can control the position of the conduction band edge of ionic cluster assemblies. The dimensionality of the solid via internal elec. fields can control the valence band edge. Through covalently linking arsenic clusters into composite building blocks, the authors also were able to tune the band gap energy. The authors used a theor. description based on cluster orbital theory to provide microscopic understanding of the electronic character of the composite building blocks and the obsd. variations in the band gap energy. Also, dimeric linkers can be used to control the band gap energy. Lastly, the authors also studied the effects of charge transfer complexes of M(CO)3 on the band gap energy.
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12Jena, P.; Sun, Q. Super atomic clusters: design rules and potential for building blocks of materials. Chem. Rev. 2018, 118, 5755– 5870, DOI: 10.1021/acs.chemrev.7b00524Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtVWku7vO&md5=b77bee290200e431d0d7af487cb3d596Super Atomic Clusters: Design Rules and Potential for Building Blocks of MaterialsJena, Puru; Sun, QiangChemical Reviews (Washington, DC, United States) (2018), 118 (11), 5755-5870CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)Atomic clusters, consisting of a few to a few thousand atoms, have emerged over the past 40 years as the ultimate nanoparticles, whose structure and properties can be controlled one atom at a time. One of the early motivations in studying clusters was to understand how the properties of matter evolve as a function of size, shape, and compn. Over the past few decades, more than 200,000 papers have been published in this field. These studies have not only led to a considerable understanding of this evolution from clusters to crystals, but also have revealed many unusual size-specific properties that make cluster science an interdisciplinary field on its own, bridging physics, chem., materials science, biol., and medicine. More importantly, the possibility of creating a new class of materials, composed of clusters instead of atoms as building blocks, has fueled the hope that one can synthesize materials from the bottom-up with unique and tailored properties. This Review focuses on the properties that set clusters apart from their corresponding bulk. Furthermore, this Review describes how different electron-counting rules can lead to the design of stable clusters, mimicking the chem. of atoms. We highlight the potential of these "superatoms" as building blocks of cluster-assembled materials. Specifically, we emphasize cluster-inspired materials for energy applications. The concluding section includes a summary of the salient features of clusters, potential challenges that remain, and an outlook for the future of cluster science.
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13Kumar, V. In Handbook of Nanophysics; CRC Press, 2010; pp 65– 87.Google ScholarThere is no corresponding record for this reference.
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14Zhao, J.; Huang, X.; Shi, R.; Tang, L.; Su, Y.; Sai, L. Ab initio global optimization of clusters. Chemical Modelling 2015, 12, 249– 292, DOI: 10.1039/9781782622703-00249Google ScholarThere is no corresponding record for this reference.
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15Kumar, V.; Esfarjani, K.; Kawazoe, Y. In Clusters and nanomaterials; Springer, 2002; pp 9– 88.Google ScholarThere is no corresponding record for this reference.
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16Knight, W.; Clemenger, K.; de Heer, W. A.; Saunders, W. A.; Chou, M.; Cohen, M. L. Electronic shell structure and abundances of sodium clusters. Phys. Rev. Lett. 1984, 52, 2141– 2143, DOI: 10.1103/PhysRevLett.52.2141Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXktlSltbY%253D&md5=ad028b548afb0a39ba6fb29a7cbb50ddElectronic shell structure and abundances of sodium clustersKnight, W. D.; Clemenger, Keith; De Heer, Walt A.; Saunders, Winston A.; Chou, M. Y.; Cohen, Marvin L.Physical Review Letters (1984), 52 (24), 2141-3CODEN: PRLTAO; ISSN:0031-9007.Mass spectra are presented for Na clusters of N atoms per cluster (N = 4-100) produced in a supersonic expansion with Ar carrier gas. The spectra show large peaks or steps at N = 8, 20, 40, 58, and 92. These can be understood in terms of 1-electron shell model in which independent delocalized at. 3s electrons are bound in a spherically sym. potential well.
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17Frauendorf, S. G.; Guet, C. Atomic clusters as a branch of nuclear physics. Annu. Rev. Nucl. Part. Sci. 2001, 51, 219– 259, DOI: 10.1146/annurev.nucl.51.101701.132354Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjtVCgsQ%253D%253D&md5=232fece073a366de3d7b29b298bf82ecAtomic clusters as a branch of nuclear physicsFrauendorf, Stefan G.; Guet, ClaudeAnnual Review of Nuclear and Particle Science (2001), 51 (), 219-259CODEN: ARPSDF; ISSN:0163-8998. (Annual Reviews Inc.)The conduction electrons in clusters of simple metal atoms are approximatively independent and free. Nucleons in nuclei also behave as delocalized and independent fermions. This generic behavior generates analogies between metal clusters and nuclei, such as the shell structure, the shapes, and the dipole vibration mode. However, there are also major differences that arise from the presence of ions in metal clusters. Fission of nuclei and clusters, and particle emission from them, reveal these differences.
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18Brack, M. The physics of simple metal clusters: self-consistent jellium model and semiclassical approaches. Rev. Mod. Phys. 1993, 65, 677– 732, DOI: 10.1103/RevModPhys.65.677Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsVCgu7o%253D&md5=93737e9fadfb0414a790cae69ab2e8f1The physics of simple metal clusters: self-consistent jellium model and semiclassical approachesBrack, MatthiasReviews of Modern Physics (1993), 65 (3, Pt. 1), 677-732CODEN: RMPHAT; ISSN:0034-6861.A review with many refs. The topics discussed include: the hierarchy of theor. approxns. leading to the jellium model; detailed description of the jellium model, including various extensions; the local-d. approxn. to exchange and correlation effects, which greatly simplifies self-consistent calcns. of the electronic structure; the semiclassical approxn. to the single-particle d. matrix, which gives a theor. framework to relate the properties of large clusters to the bulk and macroscopic surface properties; phys. properties (including ground-state binding energies, ionization potentials, and dipole polarizabilities); and treatment of collective electronic excitations from the point of view of cluster response (including some useful sum rules).
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19Itoh, M.; Kumar, V.; Adschiri, T.; Kawazoe, Y. Comprehensive study of sodium, copper, and silver clusters over a wide range of sizes 2 ≤ N ≤ 75. J. Chem. Phys. 2009, 131, 174510, DOI: 10.1063/1.3187934Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtl2hs7nK&md5=f4cabf211f7cb45e3db417eba66444d3Comprehensive study of sodium, copper, and silver clusters over a wide range of sizes 2 ≤ N ≤ 75Itoh, Masahiro; Kumar, Vijay; Adschiri, Tadafumi; Kawazoe, YoshiyukiJournal of Chemical Physics (2009), 131 (17), 174510/1-174510/19CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometric and electronic structures of NaN, CuN, and AgN metal clusters are systematically studied based on the d. functional theory over a wide range of cluster sizes 2 ≤ N ≤ 75. A remarkable similarity is obsd. between the optimized geometric structures of alkali and noble metal clusters over all of the calcd. cluster sizes N. The most stable structures are the same for the three different metal clusters for approx. half the cluster sizes N considered in this study. Even if the most stable structures are different, the same types of structures are obtained when the metastable structures are also considered. For all of the three different metal clusters, the cluster shapes change in the order of linear, planar, opened, and closed structures with increasing N. This structural-type transition leads to a deviation from the monotonic increase in the sp. vol. with N. A remarkable similarity is also obsd. for the N dependence of the cluster energy E(N) for the most stable geometric structures. The amplitude of this energy difference is larger in the two noble metal clusters than in the alkali metal cluster. This is attributed to the contribution of d electrons to the bonds. The magic no. is explicitly defined with a new criterion in the framework of total energy calcns. In the case of NaN, a semiquant. comparison between the exptl. abundance spectra and the total energy calcns. is carried out. The changing aspect of the Kohn-Sham eigenvalues from N = 2 to N = 75 is presented for the three different metal clusters. The feature of the bulk d. of states already appears at N = 75 for all of three clusters. With increasing N, the HOMO-LUMO gap clearly exhibits an odd-even alternation and converges to 0. Although there is a similarity in the N dependence of the HOMO-LUMO gap between the three metal clusters, it is much stronger between the two noble metal clusters. The growth aspect of the d band below the Fermi level of the noble metal clusters with increasing N is presented. A good correspondence is obsd. in the d characteristic of the electronic states between the cluster composed of 75 atoms and the bulk metal. The similarities obsd. in the N dependence of the geometric structures and E(N)s originate from the similarity in that of the electronic structures. (c) 2009 American Institute of Physics.
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20Martin, T.; Bergmann, T.; Göhlich, H.; Lange, T. Observation of electronic shells and shells of atoms in large Na clusters. Chem. Phys. Lett. 1990, 172, 209– 213, DOI: 10.1016/0009-2614(90)85389-TGoogle Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXlslyluro%253D&md5=aed6875f56010d485d02a3a34dccdc20Observation of electronic shells and shells of atoms in large sodium clustersMartin, T. P.; Bergmann, T.; Goehlich, H.; Lange, T.Chemical Physics Letters (1990), 172 (3-4), 209-13CODEN: CHPLBC; ISSN:0009-2614.Intensity anomalies (magic nos.) have been obsd. in the mass spectra of sodium clusters contg. up to 22,000 atoms. For small clusters (Nan, n ≤ 1500) the anomalies appear to be due to the filling of electronic shells. The mass spectra of larger clusters are well explained by the completion of icosahedral or cuboctahedral shells of atoms.
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21Echt, O.; Sattler, K.; Recknagel, E. Magic numbers for sphere packings: experimental verification in free xenon clusters. Phys. Rev. Lett. 1981, 47, 1121– 1124, DOI: 10.1103/PhysRevLett.47.1121Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXlvFaksbw%253D&md5=acfec534d48a991573843edf80775ac5Magic numbers for sphere packings: experimental verification in free xenon clustersEcht, O.; Sattler, K.; Recknagel, E.Physical Review Letters (1981), 47 (16), 1121-4CODEN: PRLTAO; ISSN:0031-9007.The existence of magic nos. for the stability of at. microclusters was shown exptl. for the first time. The magic nos. n* were obsd. via the mass spectra of free Xe clusters, nucleated in the gas phase. The obsd. nos. n* = 13, 55, and 147 coincided with the nos. of hard spheres required for complete-shell icosahedra. The appearance of further magic nos. (19, 25, 71, and 87) was only partially explained by previous calcns.
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22Leuchtner, R.; Harms, A.; Castleman, A., Jr Thermal metal cluster anion reactions: Behavior of aluminum clusters with oxygen. J. Chem. Phys. 1989, 91, 2753– 2754, DOI: 10.1063/1.456988Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXmt1Cjs7k%253D&md5=2bb6b90fdbc8ac4a3b3dac0d9c5f6948Thermal metal cluster anion reactions: behavior of aluminum clusters with oxygenLeuchtner, R. E.; Harms, A. C.; Castleman, A. W., Jr.Journal of Chemical Physics (1989), 91 (4), 2753-4CODEN: JCPSA6; ISSN:0021-9606.Aln- (n = 5-40) were produced by laser vaporization of an Al rod. Mass spectral data for the reaction of the clusters with O supports reactivity predictions of the electron droplet (jellium) model. Some anomalies suggest geometry may influence reactivity.
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23Leuchtner, R.; Harms, A.; Castleman, A., Jr Aluminum cluster reactions. J. Chem. Phys. 1991, 94, 1093– 1101, DOI: 10.1063/1.460716Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXisFClur0%253D&md5=d934ef784876daa13139f82c465f4869Aluminum cluster reactionsLeuchtner, R. E.; Harms, A. C.; Castleman, A. W., Jr.Journal of Chemical Physics (1991), 94 (2), 1093-1101CODEN: JCPSA6; ISSN:0021-9606.Al clusters, both anion and cation, were produced by using laser vaporization and reacted under thermal conditions with O in a flow tube reactor. An etching reaction was obsd. and bimol. rate consts. are reported for Aln+, n = 1-33, and Aln-, n = 5-37. For Al7+, Al13-, and Al23- no apparent reactivity was obsd. (they are produced from larger species). These correspond to predicted jellium shell closings with 20, 40, and 70 electrons, resp. Besides these exceptions, and a small odd/even alternation in reaction rates, the overall reactivity is relatively insensitive to cluster size, and ranges between ∼1 × 10-12 and 5 × 10-12 cm3/s.
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24Gong, X.; Kumar, V. Enhanced stability of magic clusters: A case study of icosahedral Al12X, X = B, Al, Ga, C, Si, Ge, Ti, As. Phys. Rev. Lett. 1993, 70, 2078– 2081, DOI: 10.1103/PhysRevLett.70.2078Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXisVWitbo%253D&md5=ea6e57af771b455cd4e019d14ef59b91Enhanced stability of magic clusters: a case study of icosahedral X-doped aluminum clusters (Al12X, X = boron, aluminum, gallium, carbon, silicon, germanium, titanium, arsenic)Gong, X. G.; Kumar, VijayPhysical Review Letters (1993), 70 (14), 2078-81CODEN: PRLTAO; ISSN:0031-9007.The electronic structures and stabilities of some 40-valence-electron, icosahedral Al12X (X = B, Al, Ga, C, Si, Ge, Ti, and As) clusters were studied with the local-spin-d.-functional theory. The stability of the Al13 cluster can be substantially enhanced by proper doping. For neutral clusters, substitution of C at the center of the icosahedron leads to the largest gain in energy. However, Al12B- is the most strongly bound in this family. These results are in agreement with recent expts. that also found Al12B- to be highly abundant.
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25Wang, L.; Zhao, J.; Zhou, Z.; Zhang, S.; Chen, Z. First-principles study of molecular hydrogen dissociation on doped Al12X (X = B, Al, C, Si, P, Mg, and Ca) clusters. J. Comput. Chem. 2009, 30, 2509– 2514, DOI: 10.1002/jcc.21239Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtF2ltLbM&md5=9fb68315f607903086837f215e72c8d0First-principles study of molecular hydrogen dissociation on doped Al12X (X = B, Al, C, Si, P, Mg, and Ca) clustersWang, Lu; Zhao, Jijun; Zhou, Zhen; Zhang, S. B.; Chen, ZhongfangJournal of Computational Chemistry (2009), 30 (15), 2509-2514CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)Inspired by the concept of superatom via substitutionally doping an Al13 magic cluster, the authors studied the H2 mol. dissocn. on the doped icosahedral Al12X (X = B, Al, C, Si, P, Mg, and Ca) clusters by d. functional theory. The computed reaction energies and activation barriers show that the concept of superatom is still valid for the catalysis behavior of doped metal clusters. The hydrogen dissocn. behavior on metal clusters characterized by the activation barrier and reaction energy can be tuned by controllable doping. Thus, doped Al12X clusters might serve as highly efficient and low-cost catalysts for hydrogen dissocn.
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26Castleman, A., Jr; Khanna, S. Clusters, superatoms, and building blocks of new materials. J. Phys. Chem. C 2009, 113, 2664– 2675, DOI: 10.1021/jp806850hGoogle Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXpsl2gsw%253D%253D&md5=894a99b3c61cd6c3cef6c9a2420e83beClusters, Superatoms, and Building Blocks of New MaterialsCastleman, A. W.; Khanna, S. N.Journal of Physical Chemistry C (2009), 113 (7), 2664-2675CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A review. The phys. and chem. properties of cluster systems at the subnano and nanoscale are often found to differ from those of the bulk and display a unique dependence on size, geometry, and compn. Indeed, most interesting are systems which have properties that vary discontinuously with the no. of atoms and compn., rather than scale linearly with size. This realm of cluster science where "one atom makes a difference" is undergoing an explosive growth in activity, and as a result of extensive collaborative activities through theory at VCU and expt. at PSU, our groups are recognized as pioneers in this area in which we have been active for many years. Herein we provide an overview of the field with primary focus on our joint undertakings which have spawned the superatom concept, giving rise to a 3-D periodic table of cluster elements and the prospect of using these as building blocks of new nanoscale materials with tailored properties.
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27Castleman, A., Jr From elements to clusters: The periodic table revisited. J. Phys. Chem. Lett. 2011, 2, 1062– 1069, DOI: 10.1021/jz200215sGoogle Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkvVSmt7c%253D&md5=2110113e2d8fb986bbb7e8bae183d114From Elements to Clusters: The Periodic Table RevisitedCastleman, A. W.Journal of Physical Chemistry Letters (2011), 2 (9), 1062-1069CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A review. Cluster science has given rise to the possibility of forming "superatoms", species that mimic elements of the periodic table but often display multiple functionalities. The ability to tailor the properties of these species opens up a new approach to forming nanoscale materials from the bottom up via cluster assembly. Recent success in designing these superatoms composing a "3D periodic table" and understanding the fundamentals governing their properties and stability are discussed, as well as prospects for the future of this field.
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28Luo, Z.; Castleman, A. W. Special and general superatoms. Acc. Chem. Res. 2014, 47, 2931– 2940, DOI: 10.1021/ar5001583Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhs1WhsL7I&md5=8d17921e2e1bb46d7a162197d88f0f43Special and General SuperatomsLuo, Zhixun; Castleman, A. WelfordAccounts of Chemical Research (2014), 47 (10), 2931-2940CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. Bridging the gap between atoms and macroscopic matter, clusters continue to be a subject of increasing research interest. Among the realm of cluster investigations, an exciting development is the realization that chosen stable clusters can mimic the chem. behavior of an atom or a group of the periodic table of elements. This major finding known as a superatom concept was originated exptl. from the study of aluminum cluster reactivity conducted in 1989 by noting a dramatic size dependence of the reactivity where cluster anions contg. a certain no. of Al atoms were unreactive toward oxygen while the other species were etched away. This observation was well interpreted by shell closings on the basis of the jellium model, and the related concept (originally termed "unified atom") spawned a wide range of pioneering studies in the 1990s pertaining to the understanding of factors governing the properties of clusters. Under the inspiration of a superatom concept, advances in cluster science in finding stable species not only shed light on magic clusters (i.e., superat. noble gas) but also enlightened the exploration of stable clusters to mimic the chem. behavior of atoms leading to the discovery of superhalogens, alk.-earth metals, superalkalis, etc. Among them, certain clusters could enable isovalent isomorphism of precious metals, indicating application potential for inexpensive superatoms for industrial catalysis, while a few superalkalis were found to validate the interesting "harpoon mechanism" involved in the superat. cluster reactivity; recently also found were the magnetic superatoms of which the cluster-assembled materials could be used in spin electronics. Up to now, extensive studies in cluster science have allowed the stability of superat. clusters to be understood within a few models, including the jellium model, also aromaticity and Wade-Mingos rules depending on the geometry and metallicity of the cluster. However, the scope of application of the jellium model and modification of the theory to account for nonspherical symmetry and nonmetal-doped metal clusters are still illusive to be further developed. It is still worth mentioning that a superatom concept has also been introduced in ligand-stabilized metal clusters which could also follow the major shell-closing electron count for a spherical, square-well potential. By proposing a new concept named as special and general superatoms, herein we try to summarize all these investigations in series, expecting to provide an overview of this field with a primary focus on the joint undertakings which have given rise to the superatom concept. To be specific, for special superatoms, we limit to clusters under a strict jellium model and simply classify them into groups based on their valence electron counts. While for general superatoms we emphasize on nonmetal-doped metal clusters and ligand-stabilized metal clusters, as well as a few isovalent cluster systems. Hopefully this summary of special and general superatoms benefits the further development of cluster-related theory, and lights up the prospect of using them as building blocks of new materials with tailored properties, such as inexpensive isovalent systems for industrial catalysis, semiconductive superatoms for transistors, and magnetic superatoms for spin electronics.
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29Jena, P. Beyond the periodic table of elements: The role of superatoms. J. Phys. Chem. Lett. 2013, 4, 1432– 1442, DOI: 10.1021/jz400156tGoogle Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXlslagtLY%253D&md5=36d3f2f3805cb14208bcb102e385aff9Beyond the Periodic Table of Elements: The Role of SuperatomsJena, PuruJournal of Physical Chemistry Letters (2013), 4 (9), 1432-1442CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A review. Atomic clusters composed of homo or heteroat. species constitute an intermediate phase of matter where every atom counts and whose properties depend on their size, shape, compn., and charge. If specific clusters mimicking the chem. of atoms can be produced, they can be thought of as man-made superatoms forming the building blocks of a new three-dimensional periodic table. Novel materials with tailored properties can then be synthesized by assembling these superatoms. This invited Perspective presents a brief summary of the pioneering works that led to this concept, and highlights the recent breakthroughs that hold promise for a new era in materials science.
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30Kroto, H. W.; Heath, J. R.; O’Brien, S. C.; Curl, R. F.; Smalley, R. E. C60: Buckminsterfullerene. Nature 1985, 318, 162– 163, DOI: 10.1038/318162a0Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XotVOktQ%253D%253D&md5=0ca5453a66ee1366682f56b357b40a10C60: buckminsterfullereneKroto, H. W.; Heath, J. R.; O'Brien, S. C.; Curl, R. F.; Smalley, R. E.Nature (London, United Kingdom) (1985), 318 (6042), 162-3CODEN: NATUAS; ISSN:0028-0836.Laser-induced vaporization of graphite produced a remarkably stable cluster, consisting of 60 C atoms. A truncated icosahedron is suggested, a polygon with 60 vertexes and 32 faces, 12 of which are pentagonal and 20 hexagonal. The C60 mol., which results when a C atom is placed at each vertex of this structure has all the valences satisfied by 2 single bonds and 1 double bond, has many resonance structures and appears to be arom.
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31Krätschmer, W.; Lamb, L. D.; Fostiropoulos, K.; Huffman, D. R. Solid C60: a new form of carbon. Nature 1990, 347, 354– 358, DOI: 10.1038/347354a0Google ScholarThere is no corresponding record for this reference.
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32Hebard, A. F.; Rosseinsky, M. J.; Haddon, R. C.; Murphy, D. W.; Glarum, S. H.; Palstra, T. T. M.; Ramirez, A. P.; Kortan, A. R. Superconductivity at 18 K in Potassium-doped C60. Nature 1991, 350, 600– 601, DOI: 10.1038/350600a0Google Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXitF2htLk%253D&md5=d58148931e0f4d856eb82d45f8023f0cSuperconductivity at 18 K in potassium-doped fullerene (C60)Hebard, A. F.; Rosseinsky, M. J.; Haddon, R. C.; Murphy, D. W.; Glarum, S. H.; Palstra, T. T. M.; Ramirez, A. P.; Kortan, A. R.Nature (London, United Kingdom) (1991), 350 (6319), 600-1CODEN: NATUAS; ISSN:0028-0836.Low-temp. studies were made of potassium-doped C60 both as films and bulk samples. This material becomes superconducting. Supercond. is demonstrated by microwave, resistivity and Meissner-effect measurements. Both polycryst. powders and thin-film samples were studied. A thin film showed a resistance transition with an onset temp. of 16 K and essentially zero resistance near 5 K. Bulk samples show a well-defined Meissner effect and magnetic-field-dependent microwave absorption beginning at 18 K. The onset of supercond. at 18 K is the highest yet obsd. for a mol. superconductor.
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33Canham, L. T. Silicon quantum wire array fabrication by electrochemical and chemical dissolution of wafers. Appl. Phys. Lett. 1990, 57, 1046– 1048, DOI: 10.1063/1.103561Google Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXmt1ahurc%253D&md5=7806af2e4e9274f981afaf5701503ef6Silicon quantum wire array fabrication by electrochemical and chemical dissolution of wafersCanham, L. T.Applied Physics Letters (1990), 57 (10), 1046-8CODEN: APPLAB; ISSN:0003-6951.Indirect evidence is presented that free-standing Si quantum wires can be fabricated without the use of epitaxial deposition or lithog. The novel approach uses electrochem. and chem. dissoln. steps to define networks of isolated wires out of bulk wafers. Mesoporous Si layers of high porosity exhibit visible (red) photoluminescence at room temps., observable with the naked eye under <1 mW unfocused (<0.1 W cm-2) green or blue laser line excitation. This is attributed to dramatic two-dimensional quantum size effects which can produce emission far above the band gap of bulk cryst. Si.
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34Uhlir, A., Jr Electrolytic shaping of germanium and silicon. Bell Syst. Tech. J. 1956, 35, 333– 347, DOI: 10.1002/j.1538-7305.1956.tb02385.xGoogle Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaG28XkslyhtA%253D%253D&md5=1934b9329e915ad3a4dfd6844e75494eElectrolytic shaping of germanium and siliconUhlir, Arthur, Jr.Bell System Technical Journal (1956), 35 (), 333-47CODEN: BSTJAN; ISSN:0005-8580.Electrolytic shaping (anodic soln.) techniques, making use of light sensitivity, rectifying barriers, appropriate voltage drops, masking, shaped cathodes, virtual cathodes, "thieves," jet impingement, injected carriers at p-n junctions, and various electrolytes permitted selection of these specialized factors to produce desired surface properties in Ge and Si intended for transistor or diode use. Voltage-current curves for both p and n Ge were given.
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35Bisi, O.; Ossicini, S.; Pavesi, L. Porous silicon: a quantum sponge structure for silicon based optoelectronics. Surf. Sci. Rep. 2000, 38, 1– 126, DOI: 10.1016/S0167-5729(99)00012-6Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXitl2hsLY%253D&md5=54c6700ca594f27656a54b483cac87fdPorous silicon: a quantum sponge structure for silicon based optoelectronicsBisi, O.; Ossicini, S.; Pavesi, L.Surface Science Reports (2000), 38 (1-3), 1-126CODEN: SSREDI; ISSN:0167-5729. (Elsevier Science B.V.)The striking photoluminescence properties of porous Si have attracted considerable research interest since their discovery in 1990. Luminescence is due to excitonic recombination quantum confined in Si nanocrystals which remain after the partial electrochem. dissoln. of Si. Porous Si is constituted by a nanocryst. skeleton (quantum sponge) immersed in a network of pores. As a result, porous Si was characterized by a very large internal surface area (of the order of 500 m2/cm3). This internal surface is passivated but remains highly chem. reactive which is one of the essential features of this new and complex material. The authors present an overview of the exptl. characterization and theor. modeling of porous Si, from the prepn. up to various applications. Emphasis is devoted to the optical properties of porous Si which are closely related to the quantum nature of the Si nanostructures. The characteristics of the various luminescence bands are analyzed and the underlying basic mechanisms are presented. In the quest of an efficient electroluminescent device, the authors survey the results for several porous Si contacts, with particular attention to the interface properties, to the stability requirement and to the carrier injection mechanisms. Other device applications are discussed as well. A review with 478 refs.
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36Beck, S. M. Studies of silicon cluster–metal atom compound formation in a supersonic molecular beam. J. Chem. Phys. 1987, 87, 4233– 4234, DOI: 10.1063/1.452877Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXmslynug%253D%253D&md5=fd5c5e5f86786110bcaf4b478c1cf353Studies of silicon cluster-metal atom compound formation in a supersonic molecular beamBeck, Steven M.Journal of Chemical Physics (1987), 87 (7), 4233-4CODEN: JCPSA6; ISSN:0021-9606.MSi15 (M = Cr, Mo, W) were formed by seeding the He carrier gas with a small fraction of M(CO)6 which dissocd. during laser vaporization to form metal atoms in the nozzle throat which reacted with Si. Incorporation of the single metal atom in the Si15 and Si16 cluster stabilizes these clusters with respect to photofragmentation. The mechanisms involved in the formation of MSi15 and their structures are discussed.
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37Beck, S. M. Mixed metal–silicon clusters formed by chemical reaction in a supersonic molecular beam: implications for reactions at the metal/silicon interface. J. Chem. Phys. 1989, 90, 6306– 6312, DOI: 10.1063/1.456684Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXkvV2gtLs%253D&md5=2d724a64fe8524caed019f7c12546e64Mixed metal-silicon clusters formed by chemical reaction in a supersonic molecular beam: implications for reactions at the metal/silicon interfaceBeck, Steven M.Journal of Chemical Physics (1989), 90 (11), 6306-12CODEN: JCPSA6; ISSN:0021-9606.A reaction was obsd. between a metal atom and Si in a supersonic jet to form metal atom-Si clusters. Using the technique of laser vaporization supersonic expansion with metal carbonyl seeded carrier gas, clusters of the form MSin were detected by ArF and F2 laser photoionization time-of-flight mass spectrometry. Three Group-VIB transition metals and Cu were investigated. The dominant product cluster peaks obsd. in the mass spectra obtained for all 3 Group VIB metals corresponds to identical but remarkable cluster stoichiometries. The dominant product peaks have formulas given by MSin (n = 16). Cu results are different than the other 3 metals, indicating the importance of the metal valence electronic structure to the chem. The metal-semiconductor clusters are relatively more stable towards photofragmentation than the bare Si-cluster of the same size. The observation of these new species may be relevant to reactions which occur at the interface between a Si wafer and deposited metals.
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38Heath, J.; O’brien, S.; Zhang, Q.; Liu, Y.; Curl, R.; Tittel, F.; Smalley, R. Lanthanum complexes of spheroidal carbon shells. J. Am. Chem. Soc. 1985, 107, 7779– 7780, DOI: 10.1021/ja00311a102Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XhsVSkuw%253D%253D&md5=fa85fc7aec246351f0c1c9ec022bd730Lanthanum complexes of spheroidal carbon shellsHeath, J. R.; O'Brien, S. C.; Zhang, Q.; Liu, Y.; Curl, R. F.; Tittel, F. K.; Smalley, R. E.Journal of the American Chemical Society (1985), 107 (25), 7779-80CODEN: JACSAT; ISSN:0002-7863.La complexes with C clusters were prepd. in a mol. beam by laser vaporization of a La-impregnated graphite disk mounted in a pulsed supersonic nozzle. Detection was accomplished by photoionization with an excimer laser, followed by time-of-flight mass spectrometry. The major obsd. La complexes were of the form CnLa (n = 44, 46, 48, ... 76) with C60La being the dominant species. No complexes were obsd. contg. >1 La atom. The only abundant bare clusters of C under these conditions were C60 and C70 which are believed to be closed, hollow shells made up of 5- and 6-membered arom. rings. All the CnLa complexes probably have the metal atom strongly bound within a spheroidal C shell.
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39Lu, X.; Chen, Z. Curved pi-conjugation, aromaticity, and the related chemistry of small fullerenes (< C60) and single-walled carbon nanotubes. Chem. Rev. 2005, 105, 3643– 3696, DOI: 10.1021/cr030093dGoogle Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVGisrfM&md5=d395bd7e490810ad684705169068e3d9Curved Pi-Conjugation, Aromaticity, and the Related Chemistry of Small Fullerenes (<C60) and Single-Walled Carbon NanotubesLu, Xin; Chen, ZhongfangChemical Reviews (Washington, DC, United States) (2005), 105 (10), 3643-3696CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review.
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40Rodríguez-Fortea, A.; Balch, A. L.; Poblet, J. M. Endohedral metallofullerenes: a unique host–guest association. Chem. Soc. Rev. 2011, 40, 3551– 3563, DOI: 10.1039/c0cs00225aGoogle Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXns12nu7o%253D&md5=86e8417e506e62c3499052e45ab977a0Endohedral metallofullerenes: a unique host-guest associationRodriguez-Fortea, Antonio; Balch, Alan L.; Poblet, Josep M.Chemical Society Reviews (2011), 40 (7), 3551-3563CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. In this tutorial review taking x-ray crystallog. characterized compds. as a starting point a walk is taken through the electronic and structural properties of endohedral metallofullerenes. After classification of the fullerenes according to the encapsulated guest, particular attention is given to identifying factors that det. the selection of a particular carbon cage network by the internal metal cluster. Some of the phys. rules that det. which particular fullerene cage is formed is discussed. Concepts such as charge transfer between the cage and the guest metal ions, the topol. of the cage, the sepns. between the 12 pentagons on the fullerene surface, and the effect of entropic factors were used to rationalize the selection of a particular cage. The roles of electrochem. and vibrational spectroscopy in combination with theor. calcns. are considered in understanding the structures of the endohedral fullerenes.
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41Lu, X.; Feng, L.; Akasaka, T.; Nagase, S. Current status and future developments of endohedral metallofullerenes. Chem. Soc. Rev. 2012, 41, 7723– 7760, DOI: 10.1039/c2cs35214aGoogle Scholar41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38fptl2msg%253D%253D&md5=ff60dcf7aaa967055584a42b42eecef0Current status and future developments of endohedral metallofullerenesLu Xing; Feng Lai; Akasaka Takeshi; Nagase ShigeruChemical Society reviews (2012), 41 (23), 7723-60 ISSN:.Endohedral metallofullerenes (EMFs), a new class of hybrid molecules formed by encapsulation of metallic species inside fullerene cages, exhibit unique properties that differ distinctly from those of empty fullerenes because of the presence of metals and their hybridization effects via electron transfer. This critical review provides a balanced but not an exhaustive summary regarding almost all aspects of EMFs, including the history, the classification, current progress in the synthesis, extraction, isolation, and characterization of EMFs, as well as their physiochemical properties and applications in fields such as electronics, photovoltaics, biomedicine, and materials science. Emphasis is assigned to experimentally obtained results, especially the X-ray crystallographic characterizations of EMFs and their derivatives, rather than theoretical calculations, although the latter has indeed enhanced our knowledge of metal-cage interactions. Finally, perspectives related to future developments and challenges in the research of EMFs are proposed. (381 references).
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42Popov, A. A.; Yang, S.; Dunsch, L. Endohedral fullerenes. Chem. Rev. 2013, 113, 5989– 6113, DOI: 10.1021/cr300297rGoogle Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmvVylsLk%253D&md5=a62bdab20b10c9be7d071a394cb8d31cEndohedral FullerenesPopov, Alexey A.; Yang, Shangfeng; Dunsch, LotharChemical Reviews (Washington, DC, United States) (2013), 113 (8), 5989-6113CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review is given on endohedral fullerenes with topics including the synthesis, mol. structures, electronic structures, spectroscopic and photophys. properties, electrochem. and spectroelectrochem., chem. and magnetic properties and potential applications.
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43Garcia-Borras, M.; Osuna, S.; Luis, J. M.; Swart, M.; Solà, M. The role of aromaticity in determining the molecular structure and reactivity of (endohedral metallo) fullerenes. Chem. Soc. Rev. 2014, 43, 5089– 5105, DOI: 10.1039/C4CS00040DGoogle Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtValsrbN&md5=80afbc881b0a995c33a8704ae3d330d5The role of aromaticity in determining the molecular structure and reactivity of (endohedral metallo)fullerenesGarcia-Borras, Marc; Osuna, Silvia; Luis, Josep M.; Swart, Marcel; Sola, MiquelChemical Society Reviews (2014), 43 (14), 5089-5105CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)The encapsulation of metal clusters in endohedral metallofullerenes (EMFs) takes place in cages that in most cases are far from being the most stable isomer in the corresponding hollow fullerenes. There exist several possible explanations for the choice of the hosting cages in EMFs, although the final reasons are actually not totally well understood. Moreover, the reactivity and regioselectivity of (endohedral metallo)fullerenes have in the past decade been shown to be generally dependent on a no. of factors, such as the size of the fullerene cage, the type of cluster that is being encapsulated, and the no. of electrons that are transferred formally from the cluster to the fullerene cage. Different rationalizations of the obsd. trends had been proposed, based on bond lengths, pyramidalization angles, shape and energies of (un)occupied orbitals, deformation energies of the cages, or sepn. distances between the pentagon rings. Recently, in our group we proposed that the quest for the max. aromaticity (max. aromaticity criterion) dets. the most suitable hosting carbon cage for a given metallic cluster (i.e. EMF stabilization), including those cases where the IPR rule is not fulfilled. Moreover, we suggested that local aromaticity plays a detg. role in the reactivity of EMFs, which can be used as a criterion for understanding and predicting the regioselectivity of different reactions such as Diels-Alder cycloaddns. or Bingel-Hirsch reactions. This review highlights different aspects of the aromaticity of fullerenes and EMFs, starting from how this can be measured and ending by how it can be used to rationalize and predict their mol. structure and reactivity.
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44Yang, S.; Wei, T.; Jin, F. When metal clusters meet carbon cages: endohedral clusterfullerenes. Chem. Soc. Rev. 2017, 46, 5005– 5058, DOI: 10.1039/C6CS00498AGoogle Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFamsbvL&md5=cd358f606c5696cc06ad4a6ae3761f68When metal clusters meet carbon cages: endohedral clusterfullerenesYang, Shangfeng; Wei, Tao; Jin, FeiChemical Society Reviews (2017), 46 (16), 5005-5058CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Fullerenes have the characteristic of a hollow interior, and this unique feature triggers intuitive inspiration to entrap atoms, ions or clusters inside the carbon cage in the form of endohedral fullerenes. In particular, upon entrapping an otherwise unstable metal cluster into a carbon cage, the so-called endohedral clusterfullerenes fulfil the mutual stabilization of the inner metal cluster and the outer fullerene cage with a specific isomeric structure which is often unstable as an empty fullerene. A variety of metal clusters have been reported to form endohedral clusterfullerenes, including metal nitrides, carbides, oxides, sulfides, cyanides and so on, making endohedral clusterfullerenes the most variable and intriguing branch of endohedral fullerenes. In this review article, we present an exhaustive review on all types of endohedral clusterfullerenes reported to date, including their discoveries, syntheses, sepns., mol. structures and properties as well as their potential applications in versatile fields such as biomedicine, energy conversion, and so on. At the end, we present an outlook on the prospect of endohedral clusterfullerenes.
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45Guo, T.; Diener, M. D.; Chai, Y.; Alford, M. J.; Haufler, R. E.; McClure, S. M.; Ohno, T.; Weaver, J. H.; Scuseria, G. E.; Smalley, R. E. Uranium stabilization of C28: a tetravalent fullerene. Science 1992, 257, 1661– 1664, DOI: 10.1126/science.257.5077.1661Google Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXjt1SitQ%253D%253D&md5=7a8b09e735da3708d18554472a7ac412Uranium stabilization of C28: a tetravalent fullereneGuo, Ting; Diener, M. D.; Chai, Yan; Alford, M. J.; Haufler, R. E.; McClure, S. M.; Ohno, T.; Weaver, J. H.; Scuseria, G. E.; Smalley, R. E.Science (Washington, DC, United States) (1992), 257 (5077), 1661-4CODEN: SCIEAS; ISSN:0036-8075.Laser vaporization expts. with graphite in a supersonic cluster beam app. indicate that the smallest fullerene to form in substantial abundance is C28. Although ab initio quantum chem. calcns. predict that this cluster will favor a tetrahedral cage structure, it is electronically open shell. Further calcns. reveal that C28 in this structure should behave as a sort of hollow superatom with an effective valence of 4. This tetravalence should be exhibited toward chem. bonding both on the outside and on the inside of the cage. Stable closed-shell derivs. of C28 with large HOMO-LUMO gaps should be attainable either by reacting at the 4 tetrahedral vertices on the outside of the C28 cage to make, for example, C28H4, or by trapping a tetravalent atom inside the cage to make endohedral fullerenes such as Ti@C28. An example of this 2nd, inside route to C28 stabilization is reported here: the laser and C-arc prodn. of U@C28.
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46Jackson, K.; Nellermoe, B. Zr@Si20: a strongly bound Si endohedral system. Chem. Phys. Lett. 1996, 254, 249– 256, DOI: 10.1016/0009-2614(96)00315-6Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XjtlSksrg%253D&md5=83902e304da97e9b0919492f3e218c95Zr@Si20: a strongly bound Si endohedral systemJackson, Koblar; Nellermoe, BritaChemical Physics Letters (1996), 254 (3,4), 249-256CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)We present the results of local-d.-approxn. (LDA) calcns. for a novel Si endohedral system, Zr@Si20. We compute an LDA endohedral binding energy for this system of 11.2 eV with respect to an isolated Zr atom and the most stable Si20 isomer known. To understand the remarkable binding in this system, we compare the electronic structure of Zr@Si20 with that of the corresponding bare cluster and with other Si20 endohedral systems. We find that the bonding of all the endohedrals can be understood on the basis of a simple model previously used to explain endohedral bonding in small carbon fullerenes. Prospects for producing Zr@Si20 exptl. are discussed.
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47Hiura, H.; Miyazaki, T.; Kanayama, T. Formation of metal-encapsulating Si cage clusters. Phys. Rev. Lett. 2001, 86, 1733– 1736, DOI: 10.1103/PhysRevLett.86.1733Google Scholar47https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXhsVWltrg%253D&md5=4a430bb1f6b302273818f6170e42f037Formation of Metal-Encapsulating Si Cage ClustersHiura, Hidefumi; Miyazaki, Takehide; Kanayama, ToshihikoPhysical Review Letters (2001), 86 (9), 1733-1736CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report the formation of a series of metal-contg. hydrogenated silicon clusters using an ion trap. Mass analyses reveal that many types of transition metal ions M+ (M = Hf, Ta, W, Re, Ir) react with silane (SiH4) to form dehydrogenated MSi+n cluster ions (n = 14, 13, 12, 11, 9, resp.) as an end product, indicating that the metal atom is endohedral and stabilizes the Si polyhedral cage. This finding is confirmed by our ab initio calcn. that WSi12 is a W-encapsulating Si12 cage cluster, and is very stable owing to both the electronic and the geometrical shell closures.
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48Kumar, V.; Kawazoe, Y. Metal-encapsulated fullerenelike and cubic caged clusters of silicon. Phys. Rev. Lett. 2001, 87, 045503, DOI: 10.1103/PhysRevLett.87.045503Google Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXltFGntro%253D&md5=2a5661eacc13b7837a75e22d47d22fe6Metal-Encapsulated Fullerenelike and Cubic Caged Clusters of SiliconKumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2001), 87 (4), 045503/1-045503/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report metal-encapsulated caged clusters of silicon from ab initio pseudopotential plane wave calcns. using generalized gradient approxn. for the exchange-correlation energy. Depending upon the size of the metal (M) atom, silicon forms fullerenelike M@Si16, M = Hf, Zr, and cubic M@Si14, M = Fe, Ru, Os, caged clusters. The embedding energy of the M atom is ≈12 eV due to strong M-Si interactions that make the cage compact. Bonding in these clusters is predominantly covalent and the HOMO-LUMO gap is ≈1.5 eV. However, an exceptionally large gap (2.35 eV) was obtained for Ti@Si16 Frank-Kasper polyhedron. Interaction between these clusters is weak, making them attractive for cluster-assembled materials.
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49Kumar, V.; Kawazoe, Y. Erratum: Metal-Encapsulated Fullerenelike and Cubic Caged Clusters of Silicon [Phys. Rev. Lett. 87, 045503 (2001)]. Phys. Rev. Lett. 2003, 91, 199901, DOI: 10.1103/PhysRevLett.91.199901Google Scholar49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVWjsro%253D&md5=55df60c904899b2ff6ccc79bef07f2f2Metal-encapsulated fullerenelike and cubic caged clusters of silicon. [Erratum to document cited in CA135:294195]Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2003), 91 (19), 199901/1CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)The fullerenelike (f) and the Frank-Kasper (FK) isomers of the Hf@Si16 cluster were reported to be nearly degenerate. The data of the binding energy, embedding energy, and the HOMO-LUMO gap presented in Table 1 for the FK isomer actually correspond to a slightly different FK isomer that was called tetracapped hexagonal antiprism [Figure 1(b)] for the metal-encapsulated Ge clusters in which one hexagon is capped by one Si atom while the other hexagon is capped by three Si atoms. This isomer and the FK isomer differ in the orientation of this capping trimer. Starting with the initial structure of the FIK isomer, a local shallow min. was obtained in which the FK isomer nearly converged with forces becoming ≈ 0.005 eV/Å or less on each ion. This lies about 0.075 eV higher in energy with the HOMO-LUMO gap of about 2.48 eV as compared to the hexagonal antiprism isomer. Starting with the coordinates of the FK local min. obtained in the optimization process, the structure was reoptimized and the FK isomer was found to have a min. with 0.07 eV higher energy than the hexagonal antiprism and 0.488 eV HOMO-LUMO gap. The energy difference between the two FK-type forms is quite small and the HOMO-LUMO gaps are similar, though the tetrahedral symmetry of the FK isomer is lowered to 3-fold symmetry in the hexagonal antiprism isomer that lifts the degeneracies of some of the levels. The differences in the bond lengths in the two isomers are small. These results also suggest low frequency modes in the vibrational spectra of the FK-type isomers of these and related clusters representing the slow rotational motion of the trimer. The overall conclusions of the paper are not affected.
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50O’brien, S.; Heath, J.; Curl, R.; Smalley, R. Photophysics of buckminsterfullerene and other carbon cluster ions. J. Chem. Phys. 1988, 88, 220– 230, DOI: 10.1063/1.454640Google Scholar50https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXosFWrsw%253D%253D&md5=4e46c8769ba31b4aad27c076012f123aPhotophysics of buckminsterfullerene and other carbon cluster ionsO'Brien, S. C.; Heath, J. R.; Curl, R. F.; Smalley, R. E.Journal of Chemical Physics (1988), 88 (1), 220-30CODEN: JCPSA6; ISSN:0021-9606.The laser-induced fragmentation behavior of pos. C cluster ions was investigated by tandem time-of-flight techniques for the jet-cooled clusters up to 80 atoms in size. Two distinct photophys. regimes were found. The first applies to clusters with 34 atoms or more, all of which dissoc. to produce even numbered fragments. Large even clusters fragment by the loss of the high energy species C2, odd ones lose a C atom. The second regime applies to clusters composed of 31 or less atoms, all of which fragment by the loss of C3. These 2 regimes are sharply sepd. by C32+ which fragments to produce smaller cluster ions in the 10-19 atom size range. Fragmentation of the large clusters occurs on a microsecond or faster time scale only at very high levels of excitation (>12.8 eV). These photophys. results are interpreted as consequences of the large clusters having edgeless, spheroidal cage structures while the small ones have linear chain or ring structures.
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51Zhu, X.; Zeng, X. C.; Lei, Y.; Pan, B. Structures and stability of medium silicon clusters. II. Ab initio molecular orbital calculations of Si12–Si20. J. Chem. Phys. 2004, 120, 8985– 8995, DOI: 10.1063/1.1690755Google Scholar51https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjs1SmsLg%253D&md5=19c9070ce5f7a6d050ea2847ab9699a1Structures and stability of medium silicon clusters. II. Ab initio molecular orbital calculations of Si12-Si20Zhu, X. L.; Zeng, X. C.; Lei, Y. A.; Pan, B.Journal of Chemical Physics (2004), 120 (19), 8985-8995CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Ab initio all-electron mol.-orbital calcns. are carried out to study the structures and relative stability of low-energy silicon clusters (Sin,n=12-20). Selected geometric isomers include those predicted by Ho et al. [Nature (London) 392, 582 (1998)] based on an unbiased search with tight-binding/genetic algorithm, as well as those found by Rata et al. [Phys. Rev. Lett. 85, 546 (2000)] based on d.-functional tight-binding/single-parent evolution algorithm. These geometric isomers are optimized at the Moller-Plesset (MP2) MP2/6-31G(d) level. The single-point energy at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d) level for several low-lying isomers are further computed. Harmonic vibrational frequency anal. at the MP2/6-31G(d) level of theory is also undertaken to assure that the optimized geometries are stable. For Si12-Si17 and Si19 the isomer with the lowest-energy at the CCSD(T)/6-31G(d) level is the same as that predicted by Ho et al., whereas for Si18 and Si20, the same as predicted by Rata et al. However, for Si14 and Si15, the vibrational frequency anal. indicates that the isomer with the lowest CCSD(T)/6-31G(d) single-point energy gives rise to imaginary frequencies. Small structural perturbation onto the Si14 and Si15 isomers can remove the imaginary frequencies and results in new isomers with slightly lower MP2/6-31G(d) energy; however the new isomers have a higher single-point energy at the CCSD(T)/6-31G(d) level. For most Sin (n=12-18,20) the low-lying isomers are prolate in shape, whereas for Si19 a spherical-like isomer is slightly lower in energy at the CCSD(T)/6-31G(d) level than low-lying prolate isomers.
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52Yoo, S.; Zeng, X. C. Structures and stability of medium-sized silicon clusters. III. Reexamination of motif transition in growth pattern from Si15 to Si20. J. Chem. Phys. 2005, 123, 164303, DOI: 10.1063/1.2043127Google Scholar52https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFyktb3F&md5=3273463d6f7d4538027915c866a40cd2Structures and stability of medium-sized silicon clusters. III. Reexamination of motif transition in growth pattern from Si15 to Si20Yoo, Soohaeng; Zeng, X. C.Journal of Chemical Physics (2005), 123 (16), 164303/1-164303/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)It has been established from expts. that stable medium-sized ionic clusters Si15-Si20 are prolate in shape. D.-functional theories (DFTs) also predict that nearly all low-lying neutral clusters in this size range are prolate in shape. Moreover, most of them are built onto two generic structural motifs, either the tricapped-trigonal-prism (TTP) Si9 motif or the six/six Si6/Si6 (sixfold-puckered hexagonal ring Si6 plus six-atom tetragonal bipyramid Si6) motif. However, it appears that the exact location of the TTP-to-six/six motif transition is dependent on the functional (e.g., PBE or BLYP) used in the DFT calcns. Here, we present total-energy calcns. for two series of clusters (one series contg. six/six motif and the other contg. the TTP motif) in the size range of Si16-Si20. The calcns. were based on all-electron DFT methods with a medium [6-311G (2d)] and a large (cc-pVTZ) basis sets, as well as coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] method with a modest (cc-pVDZ) basis set. In the DFT calcns., two popular hybrid d. functionals, the B3LYP and PBE1PBE, were selected. It is found that the B3LYP total-energy calcns. slightly favor the six/six motif, whereas the PBE1PBE calcns. slightly favor the TTP motif. The CCSD(T) total-energy calcns., however, show that isomers based on the six/six motif are energetically slightly favorable in the size range of Si16-Si20. Hence, the TTP-to-six/six motif transition is more likely to occur at Si16.
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53Kumar, V.; Kawazoe, Y. Metal-encapsulated caged clusters of germanium with large gaps and different growth behavior than silicon. Phys. Rev. Lett. 2002, 88, 235504, DOI: 10.1103/PhysRevLett.88.235504Google Scholar53https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktFGktrw%253D&md5=7957953eb0c806b2548aef1fdfd39426Metal-encapsulated caged clusters of germanium with large gaps and different growth behavior than siliconKumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2002), 88 (23), 235504/1-235504/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Metal (M)-encapsulated caged clusters of Ge are studied using the ab initio pseudopotential plane-wave method and the generalized gradient approxn. for the exchange-correlation energy. Depending upon the size of the M atom, we find Frank-Kasper polyhedral M@Ge16 for M = Ti, Zr, Hf, and capped decahedral or cubic M@Ge14 and M@Ge15 clusters for several M atoms. The growth behavior differs from the one found in M@Sin clusters. The HOMO-LUMO gaps are, however, similarly large or even higher in some cases. Cr@Ge16 and Fe@Ge15 are magnetic. The weak interaction between the clusters makes such species attractive for cluster assembled materials.
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54Ohara, M.; Koyasu, K.; Nakajima, A.; Kaya, K. Geometric and electronic structures of metal (M)-doped silicon clusters (M = Ti, Hf, Mo and W). Chem. Phys. Lett. 2003, 371, 490– 497, DOI: 10.1016/S0009-2614(03)00299-9Google Scholar54https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXitlWkt70%253D&md5=5becb923578baf48e1073c69d91ece98Geometric and electronic structures of metal (M)-doped silicon clusters (M = Ti, Hf, Mo and W)Ohara, Michiaki; Koyasu, Kiichirou; Nakajima, Atsushi; Kaya, KojiChemical Physics Letters (2003), 371 (3,4), 490-497CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The authors have studied geometric and electronic structures of metal (M) atom doped Si clusters, MSin (M = Ti, Hf, Mo and W), using mass spectrometry, a chem.-probe method and photoelectron spectroscopy. In the mass spectra for all of the mixed cluster anions, MSin-, both MSi15- and MSi16- were abundantly produced compared to neighbors. Together with the result of the adsorption reactivity and photoelectron spectroscopy, one metal atom can be encapsulated inside a Sin cage at n ≥ 15.
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55Koyasu, K.; Akutsu, M.; Mitsui, M.; Nakajima, A. Selective formation of MSi16 (M = Sc, Ti, and V). J. Am. Chem. Soc. 2005, 127, 4998– 4999, DOI: 10.1021/ja045380tGoogle Scholar55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXisVyqurs%253D&md5=76d3de747d57b19477f76b148d78e678Selective Formation of MSi16 (M = Sc, Ti, and V)Koyasu, Kiichirou; Akutsu, Minoru; Mitsui, Masaaki; Nakajima, AtsushiJournal of the American Chemical Society (2005), 127 (14), 4998-4999CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Metal-encapsulated silicon cage clusters are a new class of clusters and are opening up new avenues for silicon-based nanoscale materials. We present exptl. evidence for a highly stable cluster corresponding to M@Si16 (M = Sc, Ti, and V). Mass spectrometry and anion photoelectron spectroscopy show that the cluster features an electronically closed TiSi16 neutral core which undergoes a change in the no. of valence electrons involving (i) substitution of neighboring metals with Sc and V, or (ii) addn. of a halogen atom to the TiSi16 anion, and that VSi16F is predicted to form an ionically bound superatom complex.
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56Lau, J.; Hirsch, K.; Klar, P.; Langenberg, A.; Lofink, F.; Richter, R.; Rittmann, J.; Vogel, M.; Zamudio-Bayer, V.; Möller, T. X-ray spectroscopy reveals high symmetry and electronic shell structure of transition-metal-doped silicon clusters. Phys. Rev. A: At., Mol., Opt. Phys. 2009, 79, 053201, DOI: 10.1103/PhysRevA.79.053201Google Scholar56https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXmvF2mtLY%253D&md5=1d2818be2c778d20965efdeb4ae27c18X-ray spectroscopy reveals high symmetry and electronic shell structure of transition-metal-doped silicon clustersLau, J. T.; Hirsch, K.; Klar, Ph.; Langenberg, A.; Lofink, F.; Richter, R.; Rittmann, J.; Vogel, M.; Zamudio-Bayer, V.; Moller, T.; von Issendorff, B.Physical Review A: Atomic, Molecular, and Optical Physics (2009), 79 (5, Pt. A), 053201/1-053201/5CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)Size-selected cationic transition-metal-doped Si clusters were studied with x-ray absorption spectroscopy at the transition-metal L2,3 edges to study the local electronic structure of the dopant atoms. For VSi16+, the x-ray absorption spectrum is dominated by sharp transitions which directly reveal the formation of a highly sym. Si cage around the V atom. In spite of their different no. of valence electrons, a nearly identical local electronic structure is found for the dopant atoms in TiSi16+, VSi16+, and CrSi16+. This indicates strongly interlinked electronic and geometric properties: while the transition-metal atom imposes a geometric rearrangement on the Si cluster, the interaction with the highly sym. Si cage dets. the local electronic structure of the transition-metal dopant.
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57Furuse, S.; Koyasu, K.; Atobe, J.; Nakajima, A. Experimental and theoretical characterization of MSi16–, MGe16–, MSn16–, and MPb16– (M = Ti, Zr, and Hf): The role of cage aromaticity. J. Chem. Phys. 2008, 129, 064311, DOI: 10.1063/1.2966005Google Scholar57https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVShsbjP&md5=3ac612f41f0eaf33d2de5fd75a8f7710Experimental and theoretical characterization of MSi16-, MGe16-,MSn16-, and MPb16- (M=Ti, Zr, and Hf): The role of cage aromaticityFuruse, Shunsuke; Koyasu, Kiichirou; Atobe, Junko; Nakajima, AtsushiJournal of Chemical Physics (2008), 129 (6), 064311/1-064311/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Silicon (Si), germanium (Ge), tin (Sn), and lead (Pb) clusters mixed with a group-4 transition metal atom [M=titanium (Ti), zirconium (Zr), and hafnium (Hf)] were generated by a dual-laser vaporization method, and their properties were analyzed by means of time-of-flight mass spectroscopy and anion photoelectron spectroscopy together with theor. calcns. In the mass spectra, mixed neutral clusters of MSi16, MGe16, and MSn16 were produced specifically, but the yield of MPb16 was low. The anion photoelectron spectra revealed that MSi16, MGe16, and MSn16 neutrals have large HOMO-LUMO gaps of 1.5-1.9 eV compared to those of MPb16 (0.8-0.9 eV), implying that MSi16, MGe16, and MSn16 are evidently electronically stable clusters. Cage aromaticity appears to be an important determinant of the electronic stability of these clusters: Calcns. of nucleus-independent chem. shifts (NICSs) show that Si164-, Ge164-, and Sn164- have arom. characters with neg. NICS values, while Pb164- has an antiarom. character with a pos. NICS value. (c) 2008 American Institute of Physics.
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58Kumar, V.; Singh, A. K.; Kawazoe, Y. Smallest magic caged clusters of Si, Ge, Sn, and Pb by encapsulation of transition metal atom. Nano Lett. 2004, 4, 677– 681, DOI: 10.1021/nl0498076Google Scholar58https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXit1SqtLg%253D&md5=c1bf16896d5acd3af214941e5956cb91Smallest magic caged clusters of Si, Ge, Sn, and Pb by encapsulation of transition metal atomKumar, Vijay; Singh, Abhishek Kumar; Kawazoe, YoshiyukiNano Letters (2004), 4 (4), 677-681CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Ten atom clusters of X = Si, Ge, Sn, and Pb are known to be magic, suggesting that addn. of an atom to such clusters is generally unfavorable. However, here the authors report using an ab initio ultrasoft pseudopotential method that these clusters can be further stabilized by doping of a Ni or Pt atom, leading to some of the smallest metal encapsulated clusters of these elements. For Si and Ge, doping of Ni is optimal while for Sn and Pb, Pt is the best. The results agree with the recent observations of strong abundances and magic nature of X10Co- clusters of these elements. These findings could lead to the development of novel cluster-based nanomaterials for optoelectronic and other nanoscale applications.
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59Neukermans, S.; Janssens, E.; Chen, Z.; Silverans, R.; Schleyer, P. v. R.; Lievens, P. Extremely stable metal-encapsulated AlPb10+ and AlPb12+ clusters: Mass-Spectrometric discovery and density functional theory study. Phys. Rev. Lett. 2004, 92, 163401, DOI: 10.1103/PhysRevLett.92.163401Google Scholar59https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjvFKiurk%253D&md5=4712b9d400cfc4fe67eab6d409c75681Extremely stable metal-encapsulated AlPb10+ and AlPb12+ clusters: Mass-spectrometric discovery and density functional theory studyNeukermans, S.; Janssens, E.; Chen, Z. F.; Silverans, R. E.; Schleyer, P. v. R.; Lievens, P.Physical Review Letters (2004), 92 (16), 163401/1-163401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report the exptl. discovery of extremely stable metal-encapsulated superatom clusters of a group IVA element: AlPb10+ and AlPb12+. Ab initio d. functional geometry optimizations at the B3LYP/LANL2DZ level result in a perfect icosahedron with an exceptionally large HOMO-LUMO gap of 3.1 eV for AlPb12+, and a related structure with D4d symmetry for AlPb10+, with a HOMO-LUMO gap of 2.6 eV. Their high stability is attributed to the reinforcing influence of the most favorable closed-packed structure and optimally filled electron shells.
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60Lv, J.; Wang, Y.; Zhang, L.; Lin, H.; Zhao, J.; Ma, Y. Stabilization of fullerene-like boron cages by transition metal encapsulation. Nanoscale 2015, 7, 10482– 10489, DOI: 10.1039/C5NR01659BGoogle Scholar60https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXotVKksb0%253D&md5=79b5f0726024ac47a37711ca216e7552Stabilization of fullerene-like boron cages by transition metal encapsulationLv, Jian; Wang, Yanchao; Zhang, Lijun; Lin, Haiqing; Zhao, Jijun; Ma, YanmingNanoscale (2015), 7 (23), 10482-10489CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The stabilization of fullerene-like boron (B) cages in the free-standing form has been long sought after and a challenging problem. Studies that have been carried out for more than a decade have confirmed that the planar or quasi-planar polymorphs are energetically favored ground states over a wide range of small and medium-sized B clusters. Recently, the breakthroughs represented by Nat.Chem., 2014, 6, 727 established that the transition from planar/quasi-planar to cage-like Bn clusters occurs around n = ∼38-40, paving the way for understanding the intriguing chem. of B-fullerene. We herein demonstrate that the transition demarcation, n, can be significantly reduced with the help of transition metal encapsulation. We explore via extensive first-principles swarm-intelligence based structure searches the free energy landscapes of B24 clusters doped by a series of transition metals and find that the low-lying energy regime is generally dominated by cage-like isomers. This is in sharp contrast to that of bare B24 clusters, where the quasi-planar and rather irregular polyhedrons are prevalent. Most strikingly, a highly sym. B cage with D3h symmetry is discovered in the case of Mo or W encapsulation. The endohedral D3h cages exhibit robust thermodn., dynamic and chem. stabilities, which can be rationalized in terms of their unique electronic structure of an 18-electron closed-shell configuration. Our results indicate that transition metal encapsulation is a feasible route for stabilizing medium-sized B cages, offering a useful roadmap for the discovery of more B fullerene analogs as building blocks of nanomaterials.
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61Pyykkö, P.; Runeberg, N. Icosahedral WAu12: A predicted closed-shell species, stabilized by aurophilic attraction and relativity and in accord with the 18-electron rule. Angew. Chem., Int. Ed. 2002, 41, 2174– 2176, DOI: 10.1002/1521-3773(20020617)41:12<2174::AID-ANIE2174>3.0.CO;2-8Google Scholar61https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XltVWgtbk%253D&md5=8f35b742cc8f65f1f5aa2db92ab9f3b0Icosahedral WAu12: a predicted closed-shell species, stabilized by aurophilic attraction and relativity and in accord with the 18-electron rulePyykko, Pekka; Runeberg, NinoAngewandte Chemie, International Edition (2002), 41 (12), 2174-2176CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)The authors present ab initio HF-MP2-B3LYP studies of isoelectronic MAu12 clusters (M = Ta-, W, Re+, Au5+). Data are presented on bond length, force consts., Raman frequencies, orbital energies, HOMO-LUMO gaps.
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62Li, X.; Kiran, B.; Li, J.; Zhai, H. J.; Wang, L. S. Experimental observation and confirmation of icosahedral W@Au12 and Mo@Au12 molecules. Angew. Chem., Int. Ed. 2002, 41, 4786– 4789, DOI: 10.1002/anie.200290048Google Scholar62https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhtFCnsQ%253D%253D&md5=807cfe0412aa043f46aca3ff6f80b64eExperimental observation and confirmation of icosahedral WαAu12 and MoαAu12 moleculesLi, Xi; Kiran, Boggavarapu; Li, Jun; Zhai, Hua-Jin; Wang, Lai-ShengAngewandte Chemie, International Edition (2002), 41 (24), 4786-4789CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Icosahedral WαAu12 clusters were characterized using anion photoelectron spectroscopy (PES) and relativistic d. functional theory (DFT) calcns. Icosahedral MoαAu12 mols. were also characterized and were found to have a nearly identical structure and electronic spectrum as WαAu12, suggesting that a series of highly stable and sym. MαAu12 clusters with M= 4d elements might also exist. The WAu12- (MoAu12-) cluster was produced using laser vaporization of a mixed-Au/W (or Mo) target (approx. 10:1 at. ratio) and a helium carrier gas. The anion photoelectron spectra and theor. calcd. electron-detachment energies indicate that the WαAu12 cluster indeed has a highly sym. icosahedral structure with significant stability. The exptl. results of the MoαAu12 cluster suggest that MαAu12 clusters contg. a 4d-central atom are also stable.
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63Veldeman, N.; Höltzl, T.; Neukermans, S.; Veszprémi, T.; Nguyen, M. T.; Lievens, P. Experimental observation and computational identification of Sc@Cu16+, a stable dopant-encapsulated copper cage. Phys. Rev. A: At., Mol., Opt. Phys. 2007, 76, 011201, DOI: 10.1103/PhysRevA.76.011201Google Scholar63https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXpvFCltbc%253D&md5=3da1291ca21697807c6014441555548bExperimental observation and computational identification of Sc@Cu+16, a stable dopant-encapsulated copper cageVeldeman, Nele; Holtzl, Tibor; Neukermans, Sven; Veszpremi, Tamas; Nguyen, Minh Tho; Lievens, PeterPhysical Review A: Atomic, Molecular, and Optical Physics (2007), 76 (1, Pt. A), 011201/1-011201/4CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)We report a combined exptl. and computational study of scandium doped copper clusters. The clusters are studied with time-of-flight mass spectrometry after laser fragmentation. Enhanced stabilities for specific cluster sizes in the mass abundance spectra are discussed using both electronic (shell closing) and geometric (symmetry) arguments. The exceptional stability obsd. for Cu16Sc+ is investigated in detail computationally. D. functional geometry optimizations at the Becke-Perdew 1986-LANL 2-double-zeta (BP86/LANL2DZ) level result in a Frank-Kasper tetrahedron, encapsulating a scandium atom in a highly coordinated position. The high stability is therefore interpreted in terms of extremely stable dopant encapsulated structures featuring a closed electron shell. The thermodn. stability, as indicated by the stable backbone and large binding energy per atom, the relatively small ionization energy, and the moderate electron affinity of the neutral Cu16Sc cluster show that it has a superatom character, chem. similar to the alk.-metal atoms.
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64Hakkinen, H.; Yoon, B.; Landman, U.; Li, X.; Zhai, H. J.; Wang, L. S. On the electronic and atomic structures of small AuN- (N=4-14) clusters: A photoelectron spectroscopy and density-functional study. J. Phys. Chem. A 2003, 107, 6168– 6175, DOI: 10.1021/jp035437iGoogle ScholarThere is no corresponding record for this reference.
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65Huang, W.; Wang, L.-S. Probing the 2D to 3D structural transition in gold cluster anions using argon tagging. Phys. Rev. Lett. 2009, 102, 153401, DOI: 10.1103/PhysRevLett.102.153401Google Scholar65https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXkslKntrc%253D&md5=5c3879e2f87984c8e64711b0bc09d807Probing the 2D to 3D Structural Transition in Gold Cluster Anions Using Argon TaggingHuang, Wei; Wang, Lai-ShengPhysical Review Letters (2009), 102 (15), 153401/1-153401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Different physisorption properties by 2D and 3D isomers of Aun- clusters are obsd. and used to probe the 2D to 3D structural transition. Strong Ar clustering occurs on planar Aun- and the planar faces of the pyramidal Au20-. An abrupt change of Ar clustering at Au12- confirms the 2D to 3D structural transition at this size, where both isomers coexist. The minor 2D isomer can be titrated out by Ar to produce a clean 3D-Au12- beam and beams of Au12Arm- with enhanced 2D isomers. Using the Ar titrn. and tagging, isomer-specific photoelectron spectra for the 2D and 3D Au12- are obtained.
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66Jian, T.; Chen, X.; Li, S.-D.; Boldyrev, A. I.; Li, J.; Wang, L.-S. Probing the structures and bonding of size-selected boron and doped-boron clusters. Chem. Soc. Rev. 2019, 48, 3550– 3591, DOI: 10.1039/C9CS00233BGoogle Scholar66https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtVWktb3I&md5=a7d20fdc4510c8ed0d426f03ca9e883fProbing the structures and bonding of size-selected boron and doped-boron clustersJian, Tian; Chen, Xuenian; Li, Si-Dian; Boldyrev, Alexander I.; Li, Jun; Wang, Lai-ShengChemical Society Reviews (2019), 48 (13), 3550-3591CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Because of their interesting structures and bonding and potentials as motifs for new nanomaterials, size-selected boron clusters have received tremendous interest in recent years. In particular, boron cluster anions (Bn-) have allowed systematic joint photoelectron spectroscopy and theor. studies, revealing predominantly two-dimensional structures. The discovery of the planar B36 cluster with a central hexagonal vacancy provided the first exptl. evidence of the viability of 2D borons, giving rise to the concept of borophene. The finding of the B40 cage cluster unveiled the existence of fullerene-like boron clusters (borospherenes). Metal-doping can significantly extend the structural and bonding repertoire of boron clusters. Main-group metals interact with boron through s/p orbitals, resulting in either half-sandwich-type structures or substitutional structures. Transition metals are more versatile in bonding with boron, forming a variety of structures including half-sandwich structures, metal-centered boron rings, and metal-centered boron drums. Transition metal atoms have also been found to be able to be doped into the plane of 2D boron clusters, suggesting the possibility of metalloborophenes. Early studies of di-metal-doped boron clusters focused on gold, revealing ladder-like boron structures with terminal gold atoms. Recent observations of highly sym. Ta2B6- and Ln2Bn- (n = 7-9) clusters have established a family of inverse sandwich structures with monocyclic boron rings stabilized by two metal atoms. The study of size-selected boron and doped-boron clusters is a burgeoning field of research. Further investigations will continue to reveal more interesting structures and novel chem. bonding, paving the foundation for new boron-based chem. compds. and nanomaterials.
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67Kumar, V.; Kawazoe, Y. Metal-doped magic clusters of Si, Ge, and Sn: The finding of a magnetic superatom. Appl. Phys. Lett. 2003, 83, 2677– 2679, DOI: 10.1063/1.1609661Google Scholar67https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXns1CgsrY%253D&md5=9574dc45155c06849f0aff57364cb149Metal-doped magic clusters of Si, Ge, and Sn: The finding of a magnetic superatomKumar, Vijay; Kawazoe, YoshiyukiApplied Physics Letters (2003), 83 (13), 2677-2679CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Studies on divalent-metal (M)-atom-doped XNM (X = Si, Ge, and Sn, N = 8-12 and 14) clusters, using ab initio pseudopotential plane wave method, show that the known nine- and ten-atom capped prism units as well as 12- and 14-atom clusters of these elements can transform to magic clusters with higher symmetries and larger highest occupied-LUMO gaps. Most strikingly doping of X12 with Mn leads to an icosahedral superatom, Mn@X12, X = Ge and Sn with a high magnetic moment of 5 μB, enriching the family of M-doped clusters of semiconductors for possible nanodevice applications.
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68Rohrmann, U.; Schäfer, R. Stern-Gerlach experiments on Mn@Sn12: Identification of a paramagnetic superatom and vibrationally induced spin orientation. Phys. Rev. Lett. 2013, 111, 133401, DOI: 10.1103/PhysRevLett.111.133401Google Scholar68https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1amtrrM&md5=63814b1f5fd6b637c846637bff53e0a9Stern-Gerlach experiments on Mn@Sn12: identification of a paramagnetic superatom and vibrationally induced spin orientationRohrmann, Urban; Schaefer, RolfPhysical Review Letters (2013), 111 (13), 133401/1-133401/5CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Beam deflection expts. in inhomogeneous magnetic fields reveal a new limiting case of the magnetization distribution of isolated clusters. Endohedrally doped clusters are produced in a temp. controlled, cryogenically cooled laser ablation source. Temp. dependent expts. indicate a crucial contribution of mol. vibrations to the spin dynamics of Mn@Sn12. In its vibrational ground state the cluster behaves magnetically like a paramagnetic atom, with quantized spin states. However, excited mol. vibrations induce spin orientation in the magnetic field.
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69Rohrmann, U.; Schwerdtfeger, P.; Schäfer, R. Atomic domain magnetic nanoalloys: interplay between molecular structure and temperature dependent magnetic and dielectric properties in manganese doped tin clusters. Phys. Chem. Chem. Phys. 2014, 16, 23952– 23966, DOI: 10.1039/C4CP02994AGoogle Scholar69https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVOhu7jL&md5=62a2f6bbf1441ba2205364e1eeac70bdAtomic domain magnetic nanoalloys: interplay between molecular structure and temperature dependent magnetic and dielectric properties in manganese doped tin clustersRohrmann, Urban; Schwerdtfeger, Peter; Schaefer, RolfPhysical Chemistry Chemical Physics (2014), 16 (43), 23952-23966CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The authors present extensive temp. dependent (16-70 K) magnetic and elec. mol. beam deflection measurements on neutral Mn doped Sn clusters Mn/SnN (N = 9-18). Cluster geometries are identified by comparison of elec. deflection profiles and quantum chem. data obtained from DFT calcns. Most clusters adopt endohedral cage structures and all clusters exhibit nonvanishing magnetic dipole moments. In the high temp. regime all species show exclusively high field seeking magnetic response and the magnetic dipole moments are extd. from the shift of the mol. beam. At low nozzle temps., some of the clusters show considerably broadened beam profiles due to nonuniform deflection in the magnetic field. The results reflect the influence of the chem. environment on the magnetic properties of the transition metal in at. domain magnetic nanoalloys. Different ground state spin multiplicities and coupling of rotational and vibrational degrees of freedom with the spin angular momentum of isolated clusters of different size apparently cause these variations of spin orientation. This is discussed by taking electronic and mol. structure data into account.
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70Zhang, M.; Zhang, J.; Feng, X.; Zhang, H.; Zhao, L.; Luo, Y.; Cao, W. Magnetic superatoms in VLin (n = 1–13) clusters: A first-principles prediction. J. Phys. Chem. A 2013, 117, 13025– 13036, DOI: 10.1021/jp410489gGoogle Scholar70https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslOmsrfL&md5=c1d5a9e26c9fe9adaf738c8ff3e28b5fMagnetic Superatoms in VLin (n = 1-13) Clusters: A First-Principles PredictionZhang, Meng; Zhang, Jianfei; Feng, Xiaojuan; Zhang, Hongyu; Zhao, Lixia; Luo, Youhua; Cao, WeiJournal of Physical Chemistry A (2013), 117 (48), 13025-13036CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The authors demonstrated a first-principles investigation to search for magnetic superatoms in the vanadium-doped lithium clusters VLin (n = 1-13). The stabilities of VLin clusters were detd. through geometrical and electronic optimizations. The growth pattern of VLin in 3-space follows adding a Li atom capped on VLin-1 clusters. All doped clusters show larger relative binding energies compared with pure Lin+1 partners and display tunable magnetic properties. When n = 8-13, the VLin clusters adopt a cage-like structure with an endohedral V atom and are identified as superatoms with their magnetic moments successively decreasing from 5 to 0 μB. The isolated VLi8 superatom is emphasized due to its robust magnetic moment as well as high structural and chem. stability analogous of a single Mn2+ ion. MOs anal. shows that VLi8 has an electronic configuration of 1S21P61D5, exhibiting Hund's filling rule of maximizing the spin-like atoms. Electronic shell structures of 1S2 and 1P6 are virtually unchanged in Li9 cluster as the V atom substitutes for the embedded Li atom, indicating that the electron-shell-closing model is valid for explaining its structures and stabilities. The results show that the tailored magnetic building blocks for nanomaterials can be formed by seeding magnetic dopants into alkali metal cluster cages.
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71Reveles, J. U.; Clayborne, P. A.; Reber, A. C.; Khanna, S. N.; Pradhan, K.; Sen, P.; Pederson, M. R. Designer magnetic superatoms. Nat. Chem. 2009, 1, 310– 315, DOI: 10.1038/nchem.249Google Scholar71https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnsFOjtbc%253D&md5=b6f34fdcdf807f64e46f6c856c8dd5c6Designer magnetic superatomsReveles, J. Ulises; Clayborne, Penee A.; Reber, Arthur C.; Khanna, Shiv N.; Pradhan, Kalpataru; Sen, Prasenjit; Pederson, Mark R.Nature Chemistry (2009), 1 (4), 310-315, S310/1-S310/8CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)The quantum states in metal clusters are grouped into bunches of close-lying eigenvalues, termed electronic shells, similar to those of atoms. Filling of the electronic shells with paired electrons results in local min. in energy to give stable species called magic clusters. Selected clusters mimic chem. properties of elemental atoms on the periodic table and can be classified as superatoms. So far the work on superatoms has focused on nonmagnetic species. Here the authors propose a framework for magnetic superatoms by invoking systems that have both localized and delocalized electronic states, in which localized electrons stabilize magnetic moments and filled nearly-free electron shells lead to stable species. An isolated VCs8 and a ligated MnAu24(SH)18 are such magnetic superatoms. The magnetic superatoms' assemblies could be ideal for mol. electronic devices, as the coupling could be altered by charging or weak fields.
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72Medel, V. M.; Reveles, J. U.; Khanna, S. N.; Chauhan, V.; Sen, P.; Castleman, A. W. Hund’s rule in superatoms with transition metal impurities. Proc. Natl. Acad. Sci. U. S. A. 2011, 108, 10062– 10066, DOI: 10.1073/pnas.1100129108Google Scholar72https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXot1egtLc%253D&md5=6454824c981b5f89659604e3b2bd49eeHund's rule in superatoms with transition metal impuritiesMedel, Victor M.; Reveles, Jose Ulises; Khanna, Shiv N.; Chauhan, Vikas; Sen, Prasenjit; Castleman, A. WelfordProceedings of the National Academy of Sciences of the United States of America (2011), 108 (25), 10062-10066, S10062/1-S10062/5CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The quantum states in metal clusters bunch into supershells with assocd. orbitals having shapes resembling those in atoms, giving rise to the concept that selected clusters could mimic the characteristics of atoms and be classified as superatoms. Unlike atoms, the superatom orbitals span over multiple atoms and the filling of orbitals does not usually exhibit Hund's rule seen in atoms. Here, we demonstrate the possibility of enhancing exchange splitting in superatom shells via a composite cluster of a central transition metal and surrounding nearly free electron metal atoms. The transition metal d states hybridize with superatom D states and result in enhanced splitting between the majority and minority sets where the moment and the splitting can be controlled by the nature of the central atom. We demonstrate these findings through studies on TMMgn clusters where TM is a 3 d atom. The clusters exhibit Hund's filling, opening the pathway to superatoms with magnetic shells.
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73Ge, G.-X.; Han, Y.; Wan, J.-G.; Zhao, J.-J.; Wang, G.-H. First-principles prediction of magnetic superatoms in 4d-transition-metal-doped magnesium clusters. J. Chem. Phys. 2013, 139, 174309, DOI: 10.1063/1.4827515Google Scholar73https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslWqtLbE&md5=289f227a187fd798b76954564a4415efFirst-principles prediction of magnetic superatoms in 4d-transition-metal-doped magnesium clustersGe, Gui-Xian; Han, Yan; Wan, Jian-Guo; Zhao, Ji-Jun; Wang, Guang-HouJournal of Chemical Physics (2013), 139 (17), 174309/1-174309/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The authors theor. predict magnetic superatoms in the 4d-transition-metal-doped Mg8 clusters using a spin-polarized d. functional theory method. TcMg8 is highly energetically stable in both structure and magnetic states, and identify it as a magnetic superatom with a magnetic moment as large as 5 μB. The magnetic TcMg8 with 23 valence electrons has a configuration of 1S21P61D10 closed shell and 2S12D4 open shell, complying with Hund's rule similar to the single atom. The authors elucidate the formation mechanism of the magnetic TcMg8 superatom based on the detailed anal. of MOs, and attribute it to the large exchange interaction and moderate crystal field effect. Finally, the authors predict that the magnetic TcMg8 may exhibit semiconductor-like property with spin polarization characteristics. (c) 2013 American Institute of Physics.
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74Chauhan, V.; Medel, V. M.; Reveles, J. U.; Khanna, S. N.; Sen, P. Shell magnetism in transition metal doped calcium superatom. Chem. Phys. Lett. 2012, 528, 39– 43, DOI: 10.1016/j.cplett.2012.01.034Google Scholar74https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XisVyhs7o%253D&md5=f6239afe44521519917da825e8ca6b24Shell magnetism in transition metal doped calcium superatomChauhan, Vikas; Medel, Victor M.; Ulises Reveles, J.; Khanna, Shiv N.; Sen, PrasenjitChemical Physics Letters (2012), 528 (), 39-43CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Clusters of metallic elements with valence electron counts 2, 8, 18, 20, ... are known to be stable with filled electronic shells and large gaps between shells. Through first principles DFT studies of TMCa8 (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) clusters we identify a stable magnetic FeCa8 cluster of 24 valence electrons distributed into a closed 1S2 1P6 1D10 2S2 shell sequence and with four electrons occupying the majority 2Dxy, 2Dx2-y2, 2Dxz and 2Dyz levels while the unfilled 2Dz2 level is sepd. by a large energy gap of 0.61 eV arising from at. deformation and exchange splitting.
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75Medel, V. M.; Reveles, J. U.; Islam, M. F.; Khanna, S. N. Robust magnetic moments on impurities in metallic clusters: Localized magnetic states in superatoms. J. Phys. Chem. A 2013, 117, 4297– 4303, DOI: 10.1021/jp4012735Google Scholar75https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmtlekurw%253D&md5=2793cdf238b86adb0d96881a2e45d227Robust Magnetic Moments on Impurities in Metallic Clusters: Localized Magnetic States in SuperatomsMedel, Victor M.; Reveles, J. Ulises; Islam, M. Fhokrul; Khanna, Shiv N.Journal of Physical Chemistry A (2013), 117 (20), 4297-4303CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Introducing magnetic impurities into clusters of simple metals can create localized states for higher angular momentum quantum nos. (l = 2 or 3) that can breed magnetism analogous to that in virtual bound states in metallic hosts, offering a new recipe for magnetic superatoms. MnCan clusters contg. 6-15 Ca atoms show a spin magnetic moment of 5.0 μB irresp. of the cluster size. Theor. anal. reveals that the Mn d states hybridize only partially with superat. states and introduce extra majority and minority d states, largely localized at the Mn site, with a large gap. Successive addn. of Ca atoms introduces superat. states of varying angular momentum that are embedded in this gap, allowing control over the stability of the motifs without altering the moment. Assemblies of such clusters can offer novel electronic features due to the formation of localized magnetic quasibound states in a confined nearly free electron gas.
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76Medel, V.; Reveles, J. U.; Khanna, S. N. Magnetism of electrons in atoms and superatoms. J. Appl. Phys. 2012, 112, 064313, DOI: 10.1063/1.4752471Google Scholar76https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlOlsLrN&md5=5cd1e1b7398e52fc2bdb05e13c277eadMagnetism of electrons in atoms and superatomsMedel, Victor; Reveles, J. Ulises; Khanna, Shiv N.Journal of Applied Physics (2012), 112 (6), 064313/1-064313/7CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)The quantum states of electrons in small sym. metallic clusters are grouped into shells similar to the electronic shells in free atoms, leading to the conceptual basis for defining superatoms. The filling of the electronic shells in clusters, however, do not follow Hund's rule and usually result in non-magnetic species. By embedding a transition metal in group II atoms, one can stabilize superatoms with unpaired electronic supershells. We demonstrate this intriguing effect through electronic structure studies of MnSrn (n = 6-12) clusters within first principles generalized gradient calcns. The studies identify an unusually stable magnetic MnSr9 species with a large exchange splitting of 1.82 eV of the superat. D-states. The exchange split d-states in the Mn atom induce exchange splitting in S and D superat. shells because of the hybridization between orbitals of selected parity. The magnetic MnSr9 cluster with 25 valence electrons has filled 1S2, 1P6, 1D10, 2S2 shells, making it highly stable, and an open shell of 5 unpaired D electrons breeding the magnetic moment. The stable cluster is resistant to collapse as two motifs are united to form a supermol. (c) 2012 American Institute of Physics.
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77Pradhan, K.; Reveles, J. U.; Sen, P.; Khanna, S. Enhanced magnetic moments of alkali metal coated Sc clusters: New magnetic superatoms. J. Chem. Phys. 2010, 132, 124302, DOI: 10.1063/1.3367722Google Scholar77https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjvFGgt7o%253D&md5=bcfa8fe863d97ed12c8e861f6d9b8302Enhanced magnetic moments of alkali metal coated Sc clusters: New magnetic superatomsPradhan, Kalpataru; Reveles, J. Ulises; Sen, Prasenjit; Khanna, S. N.Journal of Chemical Physics (2010), 132 (12), 124302/1-124302/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The magnetic moments of Sc atoms can be significantly enhanced by combining them with alkali atoms. The authors results of first principles electronic structure calcns. of ScNan(1 ≤ n ≤ 12) clusters that indicate that a ScNa12 cluster consisting of a Sc atom surrounded by 12 Na atoms forming a compact icosahedral structure has a spin magnetic moment of 3μB that is three times that of an isolated Sc atom. This unusual behavior is analyzed in terms of the filling of the supershells 1S, 1P,... controlled by the nature and size of the alkali atoms and the more localized Sc 3d orbitals that hybridize weakly with Na sp orbitals. Even larger magnetic moments could be attained by controlling the relative position of 1S, 1P, and 3d states. Indeed, the studies indicate large magnetic moment five times that of an isolated Sc atom in the ScK12 and ScCs12 clusters, in which the 3d orbitals of Sc adopt a half-filled configuration, while the clusters are stabilized by filled 1S2, 1P6, and 2S2 shells, the features making them as new magnetic superatoms. (c) 2010 American Institute of Physics.
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78González-Ramírez, H.; Ulises Reveles, J.; Gómez-Sandoval, Z. High magnetic moments on binary yttrium-alkali superatoms. Chem. Phys. Lett. 2013, 583, 97– 102, DOI: 10.1016/j.cplett.2013.07.062Google Scholar78https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlSntbvK&md5=76ad407689058ee66dd44165cc5f84e3High magnetic moments on binary yttrium-alkali superatomsGonzalez-Ramirez, Henry; Ulises Reveles, J.; Gomez-Sandoval, Z.Chemical Physics Letters (2013), 583 (), 97-102CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)First principles electronic structure calcns. guided by energetic and magnetic principles of stability are conducted to predict and investigate a series of yttrium doped alkali clusters with a compact icosahedral structure and a large spin magnetic moment. The energetic stability of the YM12 (M = K, Rb and Cs) species lies on the nature of their electronic configuration and is a result of the controlled hybridization of the 4d-Y levels with the sp-alkali states. Further, the integrity of the YK12 is found to be conserved in a (YK12)2 dimer attesting for its potential as a magnetic building block for nanostructure materials.
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79Zhang, X.; Wang, Y.; Wang, H.; Lim, A.; Gantefoer, G.; Bowen, K. H.; Reveles, J. U.; Khanna, S. N. On the existence of designer magnetic superatoms. J. Am. Chem. Soc. 2013, 135, 4856– 4861, DOI: 10.1021/ja400830zGoogle Scholar79https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjsFakt7Y%253D&md5=3219b8f27465d8688f97a26afcea77c5On the Existence of Designer Magnetic SuperatomsZhang, Xinxing; Wang, Yi; Wang, Haopeng; Lim, Alane; Gantefoer, Gerd; Bowen, Kit H.; Reveles, J. Ulises; Khanna, Shiv N.Journal of the American Chemical Society (2013), 135 (12), 4856-4861CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The quantum states in small, compact metal clusters are bunched into electronic shells with electronic orbitals resembling those in atoms, enabling classification of stable clusters as superatoms. The filling of super at. orbitals, however, does not generally follow Hund's rule, and probably magnetic superatoms can should be stabilized by doping simple metal clusters with magnetic atoms. Here, the authors present evidence of the existence of a magnetic superatom and the detn. of its spin moment. The authors' approach combines 1st principles studies with neg. ion photoelectron expts. and enables a unique identification of the ground state and spin multiplicity. The studies indicate VNa8 to be a magnetic superatom with a filled d-subshell and a magnetic moment of 5.0 μB. Its low electron affinity is consistent with filled subshell and enhanced stability. The synthesis of this species opens the pathway to study the spin-dependent electronics of the new magnetic motifs.
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80Tsunoyama, H.; Akatsuka, H.; Shibuta, M.; Iwasa, T.; Mizuhata, Y.; Tokitoh, N.; Nakajima, A. Development of integrated Dry–Wet synthesis method for metal encapsulating silicon cage superatoms of M@Si16 (M = Ti and Ta). J. Phys. Chem. C 2017, 121, 20507– 20516, DOI: 10.1021/acs.jpcc.7b06449Google Scholar80https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtl2ls73P&md5=ba0f73e8bdac017a39b3a71ba1d82304Development of Integrated Dry-Wet Synthesis Method for Metal Encapsulating Silicon Cage Superatoms of M@Si16 (M = Ti and Ta)Tsunoyama, Hironori; Akatsuka, Hiroki; Shibuta, Masahiro; Iwasa, Takeshi; Mizuhata, Yoshiyuki; Tokitoh, Norihiro; Nakajima, AtsushiJournal of Physical Chemistry C (2017), 121 (37), 20507-20516CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Nanoclusters (NCs) of several to hundreds of atoms in size are prospective functional units for future nanomaterials originating in their unique, size-specific properties. To explore the field of NC-based materials science, the development of large-scale, size-exclusive synthesis methods is in high demand, as one can see from the successful evolution of fullerene science. The authors have developed a large-scale synthesis method for main group-based NC compds. by scaling up the clean dry-process with a high-power impulse magnetron sputtering. The 100 mg scale synthesis of binary NCs of M@Si16 (M = Ti and Ta) stabilized by poly(ethylene glycol) di-Me ether enables the authors to characterize their structures by an array of methods, for example, mass spectroscopy, x-ray photoemission spectroscopy, Raman spectroscopy, and 29Si NMR. Spectroscopic evidence indicates that the M@Si16 NCs are the metal-encapsulating tetrahedral silicon-cage structure satisfying the 68 electrons, closed-electronic-shell superatom.
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81Weinert, B.; Dehnen, S. Clusters–Contemporary Insight in Structure and Bonding; Springer, 2016; pp 99– 134.Google ScholarThere is no corresponding record for this reference.
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82Mayer, K.; Weßing, J.; Fässler, T. F.; Fischer, R. A. Intermetalloid clusters: molecules and solids in a dialogue. Angew. Chem., Int. Ed. 2018, 57, 14372– 14393, DOI: 10.1002/anie.201805897Google Scholar82https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhslOltr3N&md5=daf88674f23e01fe73f0fba7f062d15cIntermetalloid Clusters: Molecules and Solids in a DialogueMayer, Kerstin; Wessing, Jana; Faessler, Thomas F.; Fischer, Roland A.Angewandte Chemie, International Edition (2018), 57 (44), 14372-14393CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Atom-precise, ligand-stabilized metalloid clusters have emerged as outstanding model systems to study fundamental structure and bonding situations of compositionally related mols. and extended solid phases. However, this fascinating field of research is still largely restricted to homometallic and pseudo-heterometallic systems of closely related d-block metals. In this review, we will highlight our own and others' efforts to project the structural and compositional diversity of intermetallics with dissimilar d- and p-block metal combinations, particularly the Zintl and Hume-Rothery phases, onto the mol. level in order to bridge the still gaping chasm between heterometallic mol. coordination chem. and solid-state intermetallics. Herein, fundamental synthetic approaches, as well as structural and electronic properties of thus accessible "mol. alloys" will be addressed, and placed against their exceptional position as intermediates on the way to nanomaterials.
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83Wilson, R. J.; Weinert, B.; Dehnen, S. Recent developments in Zintl cluster chemistry. Dalton Trans. 2018, 47, 14861– 14869, DOI: 10.1039/C8DT03174FGoogle Scholar83https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhslGns7rP&md5=da6f158313aff3bc38ff446293caac9bRecent developments in Zintl cluster chemistryWilson, Robert J.; Weinert, Bastian; Dehnen, StefanieDalton Transactions (2018), 47 (42), 14861-14869CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)A review. Zintl anions were known for more than a century and were studied systematically by Eduard Zintl in the 1930s. Since then, they were studied for their interesting structures, bonding, and phys. properties - in solid Zintl phases, in solvate salts, and in soln. While their popularity remained limited for several decades, Zintl ion chem. has recently experienced a renaissance as a result of breakthroughs regarding their modifications into multinary anions that include transition metal atoms, their org. derivatization, and their oxidative linkage. A plethora of reports from the past two decades - demonstrating the ever growing variety of Zintl ion chem. - were since summarized in several review articles. Herein, the authors intend to present the most recent developments, which also shed light on Zintl anions and clusters as useful precursors for materials development, as illustrated by one recent example.
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84Scharfe, S.; Kraus, F.; Stegmaier, S.; Schier, A.; Faessler, T. F. Zintl ions, cage compounds, and intermetalloid clusters of group 14 and group 15 elements. Angew. Chem., Int. Ed. 2011, 50, 3630– 3670, DOI: 10.1002/anie.201001630Google Scholar84https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkt12jtr0%253D&md5=682afff80519bbc8bbbb6a3c9e5c623aZintl Ions, Cage Compounds, and Intermetalloid Clusters of Group 14 and Group 15 ElementsScharfe, Sandra; Kraus, Florian; Stegmaier, Saskia; Schier, Annette; Faessler, Thomas F.Angewandte Chemie, International Edition (2011), 50 (16), 3630-3670CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Discussion focuses on the enormous progress that has been made in Group 14 and Group 15 element Zintl ion chem. with an emphasis on syntheses, properties, structures, and theor. treatments. For a long time, Zintl ions of Group 14 and 15 elements were considered to be remarkable species domiciled in solid-state chem. that have unexpected stoichiometries and fascinating structures, but were of limited relevance. The revival of Zintl ions was heralded by the observation that these species, preformed in solid-state Zintl phases, can be extd. from the lattice of the solids and dissolved in appropriate solvents, and thus become available as reactants and building blocks in soln. chem. The recent upsurge of research activity in this fast-growing field has now provided a rich plethora of new compds., for example by substitution of these Zintl ions with org. groups and organometallic fragments, by oxidative coupling reactions leading to dimers, oligomers, or polymers, or by the inclusion of metal atoms under formation of endohedral cluster species and intermetalloid compds.; some of these species have good prospects in applications in materials science.
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85Fässler, T. F.; Hoffmann, S. D. Endohedral Zintl ions: intermetalloid clusters. Angew. Chem., Int. Ed. 2004, 43, 6242– 6247, DOI: 10.1002/anie.200460427Google Scholar85https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFWrt7fF&md5=e3a61bbb0c7e1cd58c288d5deffe4fa8Endohedral clusters: Endohedral Zintl ions: Intermetalloid clustersFassler, Thomas F.; Hoffmann, Stephan D.Angewandte Chemie, International Edition (2004), 43 (46), 6242-6247CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. The close race between Zintl ions and fullerides has gone into the second round, initialized by the synthesis of the sol. endohedral cluster [Pt@Pb12]2-. The structural characterization of an anion with almost ideal icosahedral symmetry illustrates that many heteroat. clusters obsd. in the gas phase can, indeed, be regarded as endohedral clusters.
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86Liu, C.; Sun, Z.-M. Recent advances in structural chemistry of Group 14 Zintl ions. Coord. Chem. Rev. 2019, 382, 32– 56, DOI: 10.1016/j.ccr.2018.12.003Google Scholar86https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXis1WnsrnN&md5=91c88db6953bcd3aeb02d3386889f651Recent advances in structural chemistry of Group 14 Zintl ionsLiu, Chao; Sun, Zhong-MingCoordination Chemistry Reviews (2019), 382 (), 32-56CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)The soln. chem. of Group 14 Zintl-type clusters is of growing interest as a result of their potential to be used as mol. building blocks for the construction of nanoscale architectures. Here we review the synthesis of homoat. and heteroat. Group 14 Zintl anions, with particular emphasis on their direct coordination to org. species, main-group elements and transition metal fragments.
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87Wilson, R. J.; Lichtenberger, N.; Weinert, B.; Dehnen, S. Intermetalloid and Heterometallic Clusters Combining p-Block (Semi) Metals with d-or f-Block Metals. Chem. Rev. 2019, 119, 8506– 8554, DOI: 10.1021/acs.chemrev.8b00658Google Scholar87https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtVensb7E&md5=cfe3350077cbe5e05bde96049ab99a78Intermetalloid and Heterometallic Clusters Combining p-Block (Semi)Metals with d- or f-Block MetalsWilson, Robert J.; Lichtenberger, Niels; Weinert, Bastian; Dehnen, StefanieChemical Reviews (Washington, DC, United States) (2019), 119 (14), 8506-8554CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. Clusters have been the subject of intense investigations since their famous definition launched by Cotton in 1963, and the area has expanded ever since. One obvious development addresses the widening of the definition of what to call a cluster: from purely (transition) metal-metal linked assemblies, as per Cotton's early denomination, to nonmetal/metal clusters or purely nonmetal cages, like fullerenes, and even noncovalent aggregates such as water clusters. The other extension concerns the broadened spectrum of compns. within the aforementioned cluster types and their corresponding structures that range from trinuclear motifs to clusters with sizes in the range of the Hb unit. This review article reports on one cluster family that has its origins in traditional Zintl anion chem. but has undergone rapid development in recent years, namely, ligand-free clusters that combine main group and transition metal atoms. Depending on the position of the transition metal atom(s), one refers to such clusters as intermetalloid (endohedral) clusters or as a special type of heterometallic clusters. The predominant synthetic access makes use of sol. Zintl anions. Other pathways for their prepn. include traditional solid state reactions of according element combinations or bottom-up syntheses employing low valent organo-main group element sources. This survey will shed light on all of these approaches, with an emphasis on the syntheses that employ sol. Zintl anion compds. The article will give a comprehensive overview of the currently known compds., their different synthesis protocols, and analytic techniques for detn. of their compns., structures, and further properties. Addnl., this survey will report peculiarities of bonding situations found within some of the cluster mols., which were studied by means of sophisticated quantum chem. investigations.
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88Klemm, W. Metalloids and their compounds with the alkali metals. P. Chem. Soc. 1958, 329– 364Google ScholarThere is no corresponding record for this reference.
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89Guloy, A. M.; Ramlau, R.; Tang, Z.; Schnelle, W.; Baitinger, M.; Grin, Y. A guest-free germanium clathrate. Nature 2006, 443, 320– 323, DOI: 10.1038/nature05145Google Scholar89https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xpslaks78%253D&md5=8c9ca3feff831cfa80e53b67a4f23a71A guest-free germanium clathrateGuloy, Arnold M.; Ramlau, Reiner; Tang, Zhongjia; Schnelle, Walter; Baitinger, Michael; Grin, YuriNature (London, United Kingdom) (2006), 443 (7109), 320-323CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)The challenges assocd. with synthesizing expanded semiconductor frameworks with cage-like crystal structures continue to be of interest. Filled low-d. germanium and silicon framework structures have distinct properties that address important issues in thermoelec. phonon glass-electron crystals, supercond. and the possibility of Kondo insulators. Interest in empty framework structures of silicon and germanium is motivated by their predicted wide optical band gaps of the same magnitude as quantum dots and porous silicon, making them and their alloys promising materials for silicon-based optoelectronic devices. Although almost-empty Na1-xSi136 has already been reported, the synthesis of guest-free germanium clathrate has so far been unsuccessful. Here we report the high-yield synthesis and characteristics of germanium with the empty clathrate-II structure through the oxidn. Ge49- of Zintl anions in ionic liqs. under ambient conditions. The approach demonstrates the potential of ionic liqs. as media for the reactions of polar intermetallic phases.
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90Bentlohner, M. M.; Waibel, M.; Zeller, P.; Sarkar, K.; Müller-Buschbaum, P.; Fattakhova-Rohlfing, D.; Fässler, T. F. Zintl clusters as wet-chemical precursors for germanium nanomorphologies with tunable composition. Angew. Chem., Int. Ed. 2016, 55, 2441– 2445, DOI: 10.1002/anie.201508246Google Scholar90https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFGms7zE&md5=0dfeb44d88cad13ed4b31dc0e28151edZintl Clusters as Wet-Chemical Precursors for Germanium Nanomorphologies with Tunable CompositionBentlohner, Manuel M.; Waibel, Markus; Zeller, Patrick; Sarkar, Kuhu; Mueller-Buschbaum, Peter; Fattakhova-Rohlfing, Dina; Faessler, Thomas F.Angewandte Chemie, International Edition (2016), 55 (7), 2441-2445CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)[Ge9]4- Zintl clusters are used as sol. germanium source for a bottom-up fabrication of Ge nanomorphologies such as inverse opal structures with tunable compn. The method is based on the assembly and oxidn. of [Ge9]4- clusters in a template mold using SiCl4, GeCl4, and PCl3 leading to Si and P-contg. Ge phases as shown by X-ray diffraction, Raman spectroscopy, and energy-dispersive X-ray anal. [Ge9]4- clusters are retained using ethylenediamine (en) as a transfer medium to a mold after removal of the solvent if water is thoroughly excluded, but are oxidized to amorphous Ge in presence of water traces. 1H NMR spectroscopy reveals the oxidative deprotonation of en by [Ge9]4-. Subsequent annealing leads to cryst. Ge. As an example for wet-chem. synthesis of complex Ge nanomorphologies, we describe the fabrication of undoped and P-doped inverse opal-structured Ge films with a rather low oxygen contents. The morphol. of the films with regular vol. porosity is characterized by SEM, TEM, and grazing incidence small-angle X-ray scattering.
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91Goicoechea, J. M.; Sevov, S. C. Deltahedral germanium clusters: Insertion of transition-metal atoms and addition of organometallic fragments. J. Am. Chem. Soc. 2006, 128, 4155– 4161, DOI: 10.1021/ja058652gGoogle Scholar91https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XitVOjtrs%253D&md5=c2872dcd3155be1e0566d447f3e9f935Deltahedral Germanium Clusters: Insertion of Transition-Metal Atoms and Addition of Organometallic FragmentsGoicoechea, Jose M.; Sevov, Slavi C.Journal of the American Chemical Society (2006), 128 (12), 4155-4161CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Reactions of nine-atom deltahedral clusters of germanium (K4Ge9) with Ni(COD)2 and/or Ni(PPh3)2(CO)2 in ethylenediamine yielded the Ni-centered heteroat. 10-atom clusters [Ni@(Ge9Ni-CO)]2- and [Ni@(Ge9Ni-en)]3-, as well as the empty 10-atom heteroat. cluster [Ge9Ni-CO]3-. A ligand exchange reaction between [Ni@(Ge9Ni-CO)]2- and potassium phenylacetylide produced the organically functionalized species [Ni@(Ge9Ni-CCPh)]3-. The empty cluster [Ge9Ni-CO]3- is a bicapped square antiprism where one of the capping vertexes is the Ni atom. The other three clusters are tricapped trigonal prisms where an addnl. tenth vertex of mono-ligated Ni caps a triangular base of the trigonal prism. As a result of this, that base opens up, and the distances within it become nonbonding. This ensures that all atoms of the cluster are equidistant from the central Ni atom, i.e., the cluster is very close to spherical. All species were structurally characterized in cryst. compds. with [K-(2,2,2-crypt)]+ countercations. They were also characterized in soln. by mass spectrometry, IR, and 13C NMR.
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92Hlukhyy, V.; He, H.; Jantke, L. A.; Fässler, T. F. The neat ternary solid K5–xCo1–xSn9 with endohedral [Co@Sn9]5– cluster units: a precursor for soluble intermetalloid [Co2@Sn17]5– clusters. Chem. - Eur. J. 2012, 18, 12000– 12007, DOI: 10.1002/chem.201201786Google Scholar92https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFOmt77M&md5=a1454a67b714e9153b95c527d00dd46cThe Neat Ternary Solid K5-xCo1-xSn9 with Endohedral [Co@Sn9]5- Cluster Units: A Precursor for Soluble Intermetalloid [Co2@Sn17]5- ClustersHlukhyy, Viktor; He, Haiyan; Jantke, Laura-Alice; Faessler, Thomas F.Chemistry - A European Journal (2012), 18 (38), 12000-12007, S12000/1-S12000/10CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)A new type of Zintl phase is presented that contains endohedrally filled clusters and that allows for the formation of intermetalloid clusters in soln. by a 1-step synthesis. The intermetallic compd. K5-xCo1-xSn9 was obtained by the reaction of a preformed Co-Sn alloy with potassium and tin at high temps. The diamagnetic saltlike ternary phase contains discrete [Co@Sn9]5- clusters that are sepd. by K+ ions. The intermetallic compd. K5-xCo1-xSn9 readily and incongruently dissolves in ethylenediamine and in the presence of 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (2.2.2-crypt), thereby giving cryst. [K([2.2.2]crypt)]5[Co2Sn17]. The novel polyanion [Co2Sn17]5- contains two Co-filled Sn9 clusters that share one vertex. Both compds. were characterized by single-crystal x-ray structure anal. The diamagnetism of K5-xCo1-xSn9 and the paramagnetism of [K([2.2.2]crypt)]5[Co2Sn17] were confirmed by superconducting quantum interference device (SQUID) and EPR measurements, resp. Quantum chem. calcns. reveal an endohedral Co1- atom in an [Sn9]4- nido cluster for [Co@Sn9]5- and confirm the stability of the paramagnetic [Co2Sn17]5- unit.
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93Hlukhyy, V.; Stegmaier, S.; van Wüllen, L.; Fässler, T. F. Endohedrally filled [Ni@Sn9]4– and [Co@Sn9]5– clusters in the neat solids Na12Ni1–xSn17 and K13–xCo1–xSn17: Crystal structure and 119Sn solid-state NMR spectroscopy. Chem. - Eur. J. 2014, 20, 12157– 12164, DOI: 10.1002/chem.201402318Google Scholar93https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXht1GrurrL&md5=110c30035b3fa8319455c845b1f10866Endohedrally Filled [Ni@Sn9]4- and [Co@Sn9]5- Clusters in the Neat Solids Na12Ni1-xSn17 and K13-xCo1-xSn17: Crystal Structure and 119Sn Solid-State NMR SpectroscopyHlukhyy, Viktor; Stegmaier, Saskia; van Wuellen, Leo; Faessler, Thomas F.Chemistry - A European Journal (2014), 20 (38), 12157-12164CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)A systematic approach to the formation of endohedrally filled atom clusters by a high-temp. route instead of the more frequent multistep syntheses in soln. is presented. Zintl phases Na12Ni1-xSn17 and K13-xCo1-xSn17, contg. endohedrally filled intermetalloid clusters [Ni@Sn9]4- or [Co@Sn9]5- beside [Sn4]4-, were obtained from high-temp. reactions. The arrangement of [Ni@Sn9]4- or [Co@Sn9]5- and [Sn4]4- clusters, which are present in the ratio 1:2, can be regarded as a hierarchical replacement variant of the hexagonal Laves phase MgZn2 on the Mg and Zn positions, resp. The alkali-metal positions are considered for the 1st time in the hierarchical relation, which leads to a comprehensive topol. parallel and a better understanding of the compn. of these compds. The positions of the alkali-metal atoms in the title compds. are related to the known inclusion of hydrogen atoms in the voids of Laves phases. The inclusion of Co atoms in the {Sn9} cages correlates strongly with the no. of K vacancies in K13-xCo1-xSn17 and K5-xCo1-xSn9, and consequently, all compds. correspond to diamagnetic valence compds. Owing to their diamagnetism, K13-xCo1-xSn17, and K5-xCo1-xSn9, as well as the d-block metal free binary compds. K12Sn17 and K4Sn9, were characterized for the 1st time by 119Sn solid-state NMR spectroscopy.
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94Scharfe, S.; Fässler, T. F.; Stegmaier, S.; Hoffmann, S. D.; Ruhland, K. [Cu@Sn9]3– and [Cu@Pb9]3–: Intermetalloid clusters with endohedral Cu atoms in spherical environments. Chem. - Eur. J. 2008, 14, 4479– 4483, DOI: 10.1002/chem.200800429Google Scholar94https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmslGiurw%253D&md5=d467d904ef0e07506a4b702db7df6895[Cu@Sn9]3- and [Cu@Pb9]3-: inter-metalloid clusters with endohedral Cu atoms in spherical environmentsScharfe, Sandra; Faessler, Thomas F.; Stegmaier, Saskia; Hoffmann, Stephan D.; Ruhland, KlausChemistry - A European Journal (2008), 14 (15), 4479-4483CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The inter-metalloid clusters [K[2.2.2](crypt)]3[Cu@E9](DMF)2 (E = Sn, Pb) were prepd. and contain nine E atoms arranged to give an almost perfect sphere around a Cu atom in the endohedrally filled Zintl ions [Cu@E9]3-. The rapid equilibration of the nine Sn atoms on the spectral NMR timescale in the Sn deriv. leads to an exceptionally sharp 63Cu NMR signal. The compds. were characterized using X-ray crystallog. and NMR (copper-63, tin-119), and their electronic structure and optimized geometry were investigated using DFT calcns.
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95Jin, X.; Espinoza-Quintero, G.; Below, B.; Arcisauskaite, V.; Goicoechea, J. M.; McGrady, J. E. Structure and bonding in a bimetallic endohedral cage, [Co2@Ge16]z–. J. Organomet. Chem. 2015, 792, 149– 153, DOI: 10.1016/j.jorganchem.2015.03.032Google Scholar95https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmslejt7w%253D&md5=d9f577787981006f3be8c0b7322042efStructure and bonding in a bimetallic endohedral cage, [Co2@Ge16]z-Jin, Xiao; Espinoza-Quintero, Gabriela; Below, Benjamin; Arcisauskaite, Vaida; Goicoechea, Jose M.; McGrady, John E.Journal of Organometallic Chemistry (2015), 792 (), 149-153CODEN: JORCAI; ISSN:0022-328X. (Elsevier B.V.)The authors report mass spectrometric evidence for the new bimetallic cluster, [Co2@Ge16]z- which is obsd. as a mono-anion in the mass spectrum but as a tetra-anion in the solid state. D. functional theory suggests that at both oxidn. levels it adopts a D2h-sym. structure based on two pentagonal bipyramids. The 3-connected vertexes of the cage are characteristic of an electron-precise (5n = 80) count, but assigning 80 of the 86 valence electrons to the cage would imply an unrealistic degree of charge sepn. The authors resolve this dilemma by showing that many of the electron pairs fulfill a dual role, contributing to the stable 80-electron count at the cage and to the 18-electron count at each metal. Thus it is not possible in this case to partition the charge into mutually exclusive subsets on the metal and on the cluster.
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96Liu, C.; Popov, I. [Co2@Ge16]4–: Localized versus delocalized bonding in two isomeric intermetalloid clusters. Chem. - Eur. J. 2018, 24, 699, DOI: 10.1002/chem.201704444Google Scholar96https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFegsb%252FJ&md5=f512b5397868181bceaf02a2cc215915[Co2@Ge16]4-: Localized versus Delocalized Bonding in Two Isomeric Intermetalloid ClustersLiu, Chao; Popov, Ivan A.; Li, Lei-Jiao; Li, Ning; Boldyrev, Alexander I.; Sun, Zhong-MingChemistry - A European Journal (2018), 24 (3), 699-705CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)We report the successful isolation and structural elucidation of two bimetallic doped [Co2@Ge16]4- clusters (α and β form), which were synthesized through the reaction of [{(ArN)2CtBu}Co(η6-toluene)] (Ar=2,6-diisopropylphenyl) and K4Ge9 in ethylenediamine (en) soln. and co-crystd. together in [K(2,2,2-crypt)]4[Co2@Ge16]·en. The α-[Co2@Ge16]4- isomer prefers a distinct D2h 3-connected architecture, whereas the deltahedral isomeric β-[Co2@Ge16]4- isomer adopts a quasi-C2h geometry and can be seen as coupling of two distorted arachno-[Co@Ge10] units. Chem. bonding analyses indicate that the skeleton of the α isomer is mainly composed of localized bonds, whereas only multicenter bonding interactions govern the geometry of the β isomer, which was further found to exhibit a fluxional behavior. The coexistence of both isomers within one unit cell links the 3-connected clusters with their deltahedral congeners, thus highlighting the structural and electronic flexibility of such discreet cluster systems.
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97Sun, Z.-M.; Xiao, H.; Li, J.; Wang, L.-S. Pd2@Sn184-: Fusion of two endohedral stannaspherenes. J. Am. Chem. Soc. 2007, 129, 9560– 9561, DOI: 10.1021/ja0728674Google Scholar97https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXnvVSiurs%253D&md5=3b7ad6523b08afcf7836ffd1e5105de6Pd2@Sn184-: Fusion of Two Endohedral StannaspherenesSun, Zhong-Ming; Xiao, Hai; Li, Jun; Wang, Lai-ShengJournal of the American Chemical Society (2007), 129 (31), 9560-9561CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Stannaspherene refers to an icosahedral 12-atom Sn cage cluster (Sn122-) and has also been found to be able to trap all transition metals to form gaseous endohedral clusters (M@Sn12-). During exploratory soln. syntheses of endohedral stannaspherenes, a new closo-deltahedral cluster, Pd2@Sn184-, has been isolated as a (2,2,2-crypt)K+ salt through the reaction of K4Sn9 and Pd[P(C6H5)3]4 in ethylenediamine solns. and characterized via X-ray crystallog. The new Pd2@Sn184- cluster has pseudo-D3d symmetry and is composed of 18 Sn atoms encapsulating two Pd atoms. It can be viewed as the fusion of two endohedral stannaspherenes (Pd@Sn122-) along their C3 axis by removing a Sn3 triangle on each Sn12 unit at the cluster-cluster interface. Electronic structure calcns. show that Pd2@Sn184- consists of a Sn184- cage with two zero-valent Pd atoms and possesses a highly stable electronic configuration.
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98Kocak, F. S.; Zavalij, P.; Lam, Y.-F.; Eichhorn, B. W. Solution dynamics and gas-phase chemistry of Pd2@Sn184–. Inorg. Chem. 2008, 47, 3515– 3520, DOI: 10.1021/ic701699dGoogle Scholar98https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXktFShsLo%253D&md5=96de2e006098fb626f29871bdf4aa4f8Solution Dynamics and Gas-Phase Chemistry of Pd2@Sn184-Kocak, F. Sanem; Zavalij, Peter; Lam, Yiu-Fai; Eichhorn, Bryan W.Inorganic Chemistry (2008), 47 (9), 3515-3520CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Sn94- reacts with Pd(PPh3)4 in ethylenediamine/toluene solvent mixts. in the presence of 2,2,2-cryptand to give the Pd2@Sn184- cluster as the K(2,2,2,-crypt)+ salt. The cluster is isostructural with Pd2@Ge184- and has a nuclearity different from that of the Pt and Ni analogs, Ni2@Sn174- and Pt2@Sn174-. The Pd2@Sn184- ion has a deltahedral capsulelike structure with 40 cluster bonding electrons and is the largest free-standing polystannide characterized to date. Like Pt2@Sn174-, the Pd2@Sn184- complex is highly dynamic in soln., showing a single 119Sn NMR resonance indicative of an intramol. liquidlike dynamic exchange. LDI-MS studies of the cryst. sample show extensive fragmentation and the formation of five gas-phase cluster series: Snx- (1 < x < 12), PdSnx-1- (4 < x < 18), Pd2Snx-2- (6 < x < 21), Pd3Snx-3- (8 < x < 21), and Pd4Snx-4- (13 < x < 21). The most abundant ion in the gas phase is the PdSn10- cluster, which presumably has an Sn10 bicapped-square-antiprismatic structure with an endohedral Pd (e.g., Ni@Pb102-).
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99Moses, M. J.; Fettinger, J. C.; Eichhorn, B. W. Interpenetrating As20 fullerene and Ni12 icosahedra in the onion-skin [As@Ni12@As20]3– ion. Science 2003, 300, 778– 780, DOI: 10.1126/science.1082342Google Scholar99https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjtlSkt7w%253D&md5=81528139b6832b3911664fac076bb028Interpenetrating As20 Fullerene and Ni12 Icosahedra in the Onion-Skin [As@Ni12@As20]3- IonMoses, Melanie J.; Fettinger, James C.; Eichhorn, Bryan W.Science (Washington, DC, United States) (2003), 300 (5620), 778-781CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The [As@Ni12@As20]3- ion was prepd. from As73- and Ni(COD)2 in ethylenediamine solns. and isolated as the Bu4P+ salt (Bu4P)4[As@Ni12@As20]·1.5en and its crystal structure was detd. The anion contains an icosahedral [Ni12(μ12-As)]3- fragment that resides at the center of an As20 dodecahedral (fullerene) cage to give an onion-skin-like [As@Ni12@As20]3- cluster with Ih point symmetry. The icosahedron and pentagonal dodecahedron are reciprocal platonic solids, and the 32 surface atoms form a dimpled geodesic sphere composed of 60 triangular faces. In the gas phase, the [As@Ni12@As20]3- ion sequentially loses all 21 As atoms to form Ni12As21-x clusters where 0 ≤ x ≤ 21, inclusively.
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100Stegmaier, S.; Fassler, T. F. A bronze matryoshka: the discrete intermetalloid cluster [Sn@Cu12@Sn20]12- in the ternary phases A12Cu12Sn21 (A = Na, K). J. Am. Chem. Soc. 2011, 133, 19758– 19768, DOI: 10.1021/ja205934pGoogle Scholar100https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsV2ju7zF&md5=3e105eb7cf0467a7612cf3dd21e94569A Bronze Matryoshka: The Discrete Intermetalloid Cluster [Sn@Cu12@Sn20]12- in the Ternary Phases A12Cu12Sn21 (A = Na, K)Stegmaier, Saskia; Faessler, Thomas F.Journal of the American Chemical Society (2011), 133 (49), 19758-19768CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The synthesis and crystal structure of the first ternary A-Cu-Sn intermetallic phases for the heavier alkali metals A = Na to Cs is reported. The title compds. A12Cu12Sn21 show discrete 33-atom intermetalloid Cu-Sn clusters {Sn@Cu12@Sn20}, which are composed of {Sn20} pentagonal dodecahedra surrounding {Cu12} icosahedra with single Sn atoms at the center. Na12Cu12Sn21 and K12Cu12Sn21 were characterized by single-crystal XRD studies, and the successful synthesis of analogous A-Cu-Sn compds. with A = Rb and Cs is deduced from powder XRD data. The isotypic A12Cu12Sn21 phases crystallize in the cubic space group Pn‾3m, with the Cu-Sn clusters adopting a fcc. arrangement. A formal charge of 12- can be assigned to the {Sn@Cu12@Sn20} cluster unit, and the interpretation of the title compds. as salt-like intermetallic phases featuring discrete anionic intermetalloid [Sn@Cu12@Sn20]12- clusters sepd. by alkali metal cations is supported by electronic structure calcns. For both Na12Cu12Sn21 and K12Cu12Sn21, DFT band structure calcns. (TB-LMTO-ASA) reveal a band gap. The discrete [Sn@Cu12@Sn20]12- cluster is analyzed in consideration of the MOs obtained from hybrid DFT calcns. (Gaussian 09) for the cluster anion. The [Sn@Cu12@Sn20]12- cluster MOs can be classified with labels indicating the nos. of radial and angular nodes, in the style of spherical shell models of cluster bonding.
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101Wang, Y.; Moses-DeBusk, M.; Stevens, L.; Hu, J.; Zavalij, P.; Bowen, K.; Dunlap, B. I.; Glaser, E. R.; Eichhorn, B. Sb@Ni12@Sb20-/+ and Sb@Pd12@Sb20n cluster anions, where n = +1, -1, -3, -4: Multi-oxidation-state clusters of interpenetrating platonic solids. J. Am. Chem. Soc. 2017, 139, 619– 622, DOI: 10.1021/jacs.6b12109Google Scholar101https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFCgs7nM&md5=932f5ede463745e7f6e903a417be5f75Sb@Ni12@Sb20-/+ and Sb@Pd12@Sb20n Cluster Anions, Where n = +1, -1, -3, -4: Multi-Oxidation-State Clusters of Interpenetrating Platonic SolidsWang, Yi; Moses-DeBusk, Melanie; Stevens, Lauren; Hu, Junkai; Zavalij, Peter; Bowen, Kit; Dunlap, Brett I.; Glaser, Evan R.; Eichhorn, BryanJournal of the American Chemical Society (2017), 139 (2), 619-622CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)K5Sb4 and K3Sb7 Zintl ion precursors react with Pd(PPh3)4 in ethylenediamine/toluene/PBu4+ solns. to give crystals of Sb@Pd12@Sb20n-/PBu4+ salts, where n = 3, 4. The clusters are structurally identical in the two charge states, with nearly perfect Ih point symmetry, and can be viewed as an Sb@Pd12 icosahedron centered inside of an Sb20 dodecahedron. The metric parameters suggest very weak Sb-Sb and Pd-Pd interactions with strong radial Sb-Pd bonds between the Sb20 and Pd12 shells. All-electron DFT anal. shows the 3- ion to be diamagnetic with Ih symmetry and a 1.33 eV HOMO-LUMO gap, whereas the 4- ion undergoes a Jahn-Teller distortion to an S = 1/2 D3d structure with a small 0.1 eV gap. The distortion is predicted to be small and is not discernible by crystallog. Laser desorption-ionization time-of-flight mass spectrometry (LDI-TOF MS) studies of the cryst. samples show intense parent Sb@Pd12@Sb20- ions (neg. ion mode) and Sb@Pd12@Sb20+ (pos. ion mode) along with series of Sb@Pd12-y@Sb20-x-/+ ions. Ni(cyclooctadiene)2 reacts with K3Sb7 in en/tol/Bu4PBr solvent mixts. to give black ppts. of Sb@Ni12@Sb20n- salts that give similar Sb@Ni12@Sb20-/+ parent ions and Sb@Ni12-y@Sb20-x-/+ degrdn. series in the resp. LDI-TOF MS studies. The solid-state and gas-phase studies of the icosahedral Sb@M12@Sb20n-/n+ ions show that the clusters can exist in the -4, -3, -1, +1 (M = Pd) and +1, -1 (M = Ni) oxidn. states. These multiple-charge-state clusters are reminiscent of redox-active fullerenes (e.g., C60n, where n = +1, 0, -1, -2, -3, -4, -5, -6).
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102Li, Z.; Ruan, H.; Wang, L.; Liu, C.; Xu, L. Counterion-induced crystallization of intermetalloid Matryoshka clusters [Sb@Pd12@Sb20]3-,4-. Dalton Trans. 2017, 46, 3453– 3456, DOI: 10.1039/C7DT00342KGoogle Scholar102https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXisVGhs7s%253D&md5=9c1e4c1c5dc7c5bdb5cc2cecacfd7812Counterion-induced crystallization of intermetalloid Matryoshka clusters [Sb@Pd12@Sb20]3-,4-Li, Zhenyu; Ruan, Huapeng; Wang, Lulu; Liu, Caiping; Xu, LiDalton Transactions (2017), 46 (11), 3453-3456CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)Two intermetalloid Matryoshka cluster anions [Sb@Pd12@Sb20]3-,4- obtained from the reaction of KSb and Pd(PPh3)4 were isolated as [K(2,2,2-cryptand)]+ and [K(18-crown-6)]+ salt, resp., and characterized by x-ray crystallog., EPR measurement and DFT theor. calcns.
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103Adamo, C.; Barone, V. Toward reliable density functional methods without adjustable parameters: The PBE0 model. J. Chem. Phys. 1999, 110, 6158– 6170, DOI: 10.1063/1.478522Google Scholar103https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXitVCmt7Y%253D&md5=cad4185c69f9232753497f5203d6dc9fToward reliable density functional methods without adjustable parameters: the PBE0 modelAdamo, Carlo; Barone, VincenzoJournal of Chemical Physics (1999), 110 (13), 6158-6170CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We present an anal. of the performances of a parameter free d. functional model (PBE0) obtained combining the so called PBE generalized gradient functional with a predefined amt. of exact exchange. The results obtained for structural, thermodn., kinetic and spectroscopic (magnetic, IR and electronic) properties are satisfactory and not far from those delivered by the most reliable functionals including heavy parameterization. The way in which the functional is derived and the lack of empirical parameters fitted to specific properties make the PBE0 model a widely applicable method for both quantum chem. and condensed matter physics.
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104Bruna, P. J.; Wright, J. S. Theoretical study of the ionization potentials of boron dimer. J. Phys. Chem. 1990, 94, 1774– 1781, DOI: 10.1021/j100368a014Google Scholar104https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXht1Gmtr4%253D&md5=d6f2f74cb8fd2a0e4e619542578ba862Theoretical study of the ionization potentials of boron dimerBruna, Pablo J.; Wright, James S.Journal of Physical Chemistry (1990), 94 (5), 1774-81CODEN: JPCHAX; ISSN:0022-3654.Extensive MRD-CI calcns. carried out with a contracted 6s5p2d1f Gaussian basis set indicate that B2+ has a X2Σg+ (σg2σu2σ9) ground and a low-lying I2Πu(σg2σu2πu) state (Te = 0.25 eV). The computed dissocn. energies De are 1.90 eV for X2Σg+ and 1.65 eV for 12Πu. The adiabatic ionization potentials (IP) of B2 from X3Σg3(σg2σu2πu2) into X2Σg+(πu2 → σg,∞) and into 1iΠu(πu → ∞) are 8.99 and 9.24 eV, resp.; both results are expected to underestimate the true values by about 0.15 eV. The present data do not support recent exptl. and ab initio results from Hanley, et al., (1988). Those authors reported a 2Πu ground state, with a De of 0.8 ± 0.6 eV (0.7 eV) and an adiabatic IP (X3Σg- → 2Πu) of 10.3 eV (8.9 eV), with values in parentheses corresponding to their ab initio results. Since the photoelectron spectrum of B2 (not yet recorded to our knowledge) represents a valuable and alternative exptl. technique for the spectroscopic characterization of low-lying states of B2+, the IP's are investigated here for one-electron ionization processes having X3Σg-, 15Σu-, and 13Πu of B2 as lower state. The corresponding Franck-Condon factors are also reported.
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105Rohlfing, C. M.; Martin, R. L. A theoretical study of the isovalent diatomics carbon dimer, silicon dimer, and silicon monocarbide. J. Phys. Chem. 1986, 90, 2043– 2046, DOI: 10.1021/j100401a014Google Scholar105https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XhvFGls7k%253D&md5=fe61f1206f7ba72981dba3689175854fA theoretical study of the isovalent diatomics carbon dimer, silicon dimer, and silicon monocarbideRohlfing, Celeste McMichael; Martin, Richard L.Journal of Physical Chemistry (1986), 90 (10), 2043-6CODEN: JPCHAX; ISSN:0022-3654.Ab initio calcns. on the mols. C2, Si2, and SiC are performed to det. equil. geometries (Re) and spectroscopic consts. (ωe, ωexi, and Ee) for various electronic states. A large basis set including 2 d functions on each atom is used, and electron correlation is treated by 2 different methods. The 1st approach is that of Moeller-Plesset perturbation theory based on a UHF ref. function. The 2nd approach is that of externally contracted CI based on a multireference function of the complete-active-space type. Good agreement between theory and expt. is achieved for the homonuclear diatomics. The best theor. value obtained for the ground-state harmonic frequency ωe of SiC is 940 cm-1. After consideration of the remaining basis set and correlation effects, an est. of 975 ± 10 cm-1 is made for ωe in the unobserved mol. SiC. Finally, a comparison is made between the 2 theor. approaches used in this study.
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106Bauschlicher, C. W., Jr; Barnes, L. A.; Taylor, P. R. Lowest ionization potentials of aluminum dimer. J. Phys. Chem. 1989, 93, 2932– 2935, DOI: 10.1021/j100345a017Google Scholar106https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXhs1Slt7c%253D&md5=e7639d9966abd60497f5c7b830171cceLowest ionization potentials of aluminum dimerBauschlicher, Charles W., Jr.; Barnes, Leslie A.; Taylor, Peter R.Journal of Physical Chemistry (1989), 93 (8), 2932-5CODEN: JPCHAX; ISSN:0022-3654.Potential curves for the lowest two electronic states (X2Σg+ and A2Πu) of Al2+ have been computed by using complete active space SCF/multireference CI wave functions and large Gaussian basis sets. The lowest observable vertical ionization potential (to Al2+ X2Σg+) of the Al2 X3Πu ground state is calcd. to occur around 6.1 eV, in excellent agreement with the exptl. range of 6.0-6.42 eV obtained in recent cluster ionization studies by Cox and co-workers. The second vertical ionization potential (to Al2+ A2Πu) occurs near 6.4 eV, also within the exptl. range. The adiabatic ionization potential of 5.90 eV is in good agreement with the value of 5.8-6.1 eV deduced by Hanley and co-workers from the difference in thresholds between collision-induced dissocn. processes of Al3+. The computed ionization potential values are somewhat larger than those deduced from branching ratio sin cluster fragmentation expts. by Jarroled and wo-workers. The observation of an ionization threshold below 6.42 eV is shown to be incompatible with an Al2 ground electronic state assignment of 3Σg-, but the sepn. between the two lowest states of Al2 is so small that it is likely that both are populated in the expts., so that this does not provide unambiguous support for the recent theor. assignment of the ground state as 3Πu.
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107Huber, K.-P.; Herzberg, G. Constants of diatomic molecules; Van Nostrand Reinhold Company: New York, 1979.Google ScholarThere is no corresponding record for this reference.
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108Pacchioni, G. On the ground-state properties of the germanium dimer. Chem. Phys. Lett. 1984, 107, 70– 71, DOI: 10.1016/0009-2614(84)85358-0Google Scholar108https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXkt1ylsrc%253D&md5=055c77a6efc57055d45339954c61c367On the ground-state properties of the germanium dimerPacchioni, GianfrancoChemical Physics Letters (1984), 107 (1), 70-1CODEN: CHPLBC; ISSN:0009-2614.The bond length, vibrational frequency, and dissocn. energy of the Ge2 mol. were calcd. Effective-core-potential Hartree-Fock calcns. followed by extensive CI gave Re = 4.60 bohr, ωe = 217 cm-1, De = 2.54 eV. These values are discussed and compared with those of previous theor. work and with the available exptl. data.
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109Ho, J.; Polak, M. L.; Ervin, K. M.; Lineberger, W. C. Photoelectron spectroscopy of nickel group dimers: Ni2, Pd2, and Pt2. J. Chem. Phys. 1993, 99, 8542– 8551, DOI: 10.1063/1.465577Google Scholar109https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsVOktb4%253D&md5=4e58af3b448827ae92cbf6489a1198c6Photoelectron spectroscopy of nickel group dimers: the nickel palladium, and platinum diatomic mononegative ions (Ni2-, Pd2-, and Pt2-)Ho, Joe; Polak, Mark L.; Ervin, Kent M.; Lineberger, W. C.Journal of Chemical Physics (1993), 99 (11), 8542-51CODEN: JCPSA6; ISSN:0021-9606.Neg. ion photoelectron spectra of Ni2-, Pd2-, Pt2- are presented for electron binding energies up to 3.35 eV at an instrumental resoln. of 8-10 meV. The metal cluster anions are prepd. in a flowing afterglow ion source. Each dimer exhibits multiple low-lying electronic states and a vibrationally resolved ground state transition. Franck-Condon analyses yielded the anion and neutral vibrational frequencies and the bond length changes between anion and neutral. The electron affinities are detd. to be EA (Ni2) = 0.926 ± 0.010 eV, EA (Pd2) = 1.685 ± 0.008 eV, and EA (Pt2) = 1.898 ± 0.008 eV. The electronic configurations of the ground states are tentatively assigned. Comparison of the nickel group dimers to the coinage metal dimers sheds light on the d orbital contribution to the metal bonding in the nickel group dimers.
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110Ghosh, A.; Chaudhuri, R. K.; Chattopadhyay, S. Relativistic state-specific multireference coupled cluster theory description for bond-breaking energy surfaces. J. Chem. Phys. 2016, 145, 124303, DOI: 10.1063/1.4962911Google Scholar110https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsFOmsr3O&md5=bf91a14bb5032913b1e7c40769edf7a2Relativistic state-specific multireference coupled cluster theory description for bond-breaking energy surfacesGhosh, Anirban; Chaudhuri, Rajat K.; Chattopadhyay, SudipJournal of Chemical Physics (2016), 145 (12), 124303/1-124303/15CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A four-component (4c) relativistic state specific multireference coupled cluster (4c-SSMRCC) method has been developed and applied to compute the ground state spectroscopic consts. of Ag2, Cu2, Au2, and I2. The ref. functions used in these calcns. are obtained using computationally inexpensive improved virtual orbital-complete active space CI scheme. Rigorous size-extensivity and insensitivity towards the intruder state problem make our method an interesting choice for the calcn. of the dissocn. energy surface. To the best of our knowledge, this study is the first implementation of the SSMRCC within the relativistic framework. The overall agreement of our results, employing the smallest model space, with both theor. and exptl. ref. values indicates that the 4c-SSMRCC method can be fruitfully used to describe electronic structures and assocd. properties of systems contg. heavy elements. We observe a relativistic bond stabilization for the coinage metal dimers while the I-I bond is weakened by the relativistic effects. (c) 2016 American Institute of Physics.
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111Suzumura, T.; Nakajima, T.; Hirao, K. Ground-stale properties of MH, MCl, and M2 (M = Cu, Ag, and Au) calculated by a scalar relativistic density functional theory. Int. J. Quantum Chem. 1999, 75, 757– 766, DOI: 10.1002/(SICI)1097-461X(1999)75:4/5<757::AID-QUA42>3.0.CO;2-RGoogle Scholar111https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXntlyksrw%253D&md5=d91c1f41716c5b75ecb580e6ac71e981Ground-state properties of MH, MCl, and M2 (M = Cu, Ag, and Au) calculated by a scalar relativistic density functional theorySuzumura, Toshihisa; Nakajima, Takahito; Hirao, KimihikoInternational Journal of Quantum Chemistry (1999), 75 (4/5), 757-766CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)The effects of relativity on the bond lengths, vibrational frequencies, dissocn. energies, and dipole moments of the ground states of the group IB hydrides MH, chlorides MCl, and dimers M2 (M = Cu, Ag, and Au) have been studied by relativistic d. functional theory (DFT) with the B88 plus one-parameter progressive (BOP) exchange-correlation functional. The relativistic effects were included through a scalar relativistic scheme by the elimination of the small components (RESC) of the four-component Dirac spinors. Comparisons were made between all-electron results using the nonrelativistic Hamiltonian, results with quasi-relativistic effective core potentials (ECP), and results with a spin-free RESC scheme. The RESC approach clearly works very well. The bond distances, vibrational frequencies, and dissocn. energies show good agreement with the expt. The expected trends of bond length decrease, harmonic vibrational frequency increase, and dipole moment decrease with relativity are found. Although the dissocn. energy increases with the relativity for hydrides and dimers, the reverse trend is obsd. for chlorides. A quasi-relativistic ECP also works well for hydrides. However, ECP gives a rather poor description for chlorides and dimers.
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112Miralrio, A.; Sansores, L. E. On the search of stable, aromatic and ionic endohedral compounds of C28: A theoretical study. Comput. Theor. Chem. 2016, 1083, 53– 63, DOI: 10.1016/j.comptc.2016.03.010Google Scholar112https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XksFKktLY%253D&md5=457166fa9aa2bec6324575f7cc01eff1On the search of stable, aromatic and ionic endohedral compounds of C28: A theoretical studyMiralrio, Alan; Sansores, Luis EnriqueComputational & Theoretical Chemistry (2016), 1083 (), 53-63CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The X@C28 compds. form the family of the smallest endohedral fullerenes. Currently, they consist of C28, which is endohedrally doped with group-4 elements (Ti, Zr, Hf) and U. We have studied the electronic properties, equil. geometries, binding energies and other properties of several X@C28 at the PBE/def2-TZVP level. These were compared with the tetraanion C4-28. For this study we have chosen elements from groups 4, 14 and Sc as endohedral dopants for being many of them tetravalent. In addn., we studied by the first time the entire group-10 (Ni, Pd and Pt) as endohedral dopant of C28. To elucidate the stability of these ionic compds., we have studied their binding energies. Our results show that a big pos. binding energy is necessary but not enough to det. the stability of these endohedral fullerenes. We propose that a HOMO-LUMO gap around 2 eV results in less reactive compds., property only shown by group-4 compds. Some compds. have arom. character in all rings according with their NICS(0)iso and reparametrized HOMA indexes. In addn., the charge distribution have been studied with NBO and Hirshfeld population anal. as well as electrostatic potential maps in order to find similarities between them and that shown by the tetraanion C4-28. The most stable compds. are the group-4 X@C28 which form compds.: energetically favorable, less reactive, ionic and arom. Our results are compared with available exptl. information about the formation of these compds.
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113Chase, B.; Herron, N.; Holler, E. Vibrational spectroscopy of fullerenes (C60 and C70). Temperature dependant studies. J. Phys. Chem. 1992, 96, 4262– 4266, DOI: 10.1021/j100190a029Google Scholar113https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XisVCjtro%253D&md5=3053f64f8562419b6f032b810166da38Vibrational spectroscopy of fullerenes (C60 and C70). Temperature dependant studiesChase, Bruce; Herron, Norm; Holler, EddJournal of Physical Chemistry (1992), 96 (11), 4262-6CODEN: JPCHAX; ISSN:0022-3654.The Fourier-transform (FT)-Raman and FTIR spectra of C60 and C70 were obtained under high resoln. conditions, both for solid material and in soln. The very small differences in frequency and line width for soln. and solid-state spectra are interpreted in terms of minimal intermol. interactions. The temp. dependence of the IR modes shows a phase transition near 260 K, in agreement with x-ray results. Below the phase transition temp., fine structure develops on several of the IR modes, indicative of an increase in solid-state interactions.
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114Wu, X.; Liang, X.; Du, Q.; Zhao, J.; Chen, M.; Lin, M.; Wang, J.; Yin, G.; Ma, L.; King, R. B. Medium-sized (n = 14–20) clusters: a combined study of photoelectron spectroscopy and DFT calculations. J. Phys.: Condens. Matter 2018, 30, 354002, DOI: 10.1088/1361-648X/aad65aGoogle Scholar114https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvFKrtLvO&md5=4fb4dba4acd6c10c3a8a24c1357e806bMedium-sized Sin- (n = 14-20) clusters: a combined study of photoelectron spectroscopy and DFT calculationsWu, Xue; Liang, Xiaoqing; Du, Qiuying; Zhao, Jijun; Chen, Maodu; Lin, Miao; Wang, Jiashuai; Yin, Guangjia; Ma, Lei; King, R. Bruce; von Issendorff, BerndJournal of Physics: Condensed Matter (2018), 30 (35), 354002/1-354002/10CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Size-selected anionic silicon clusters, Sin- (n = 14-20), have been investigated by photoelectron spectroscopy and d. functional theory (DFT) calcns. Low-energy structures of the clusters are globally searched for by using a genetic algorithm based on DFT calcns. The electronic d. of states and vertical detachment energies have been simulated by using ten DFT functionals and compared to the exptl. results. We systematically evaluated the DFT functionals for the calcn. of the energetics of silicon clusters. CCSD(T) single-point energies based on MP2 optimized geometries for selected isomers of Sin- are also used as benchmark for the energy sequence. The HSE06 functional with aug-cc-pVDZ basis set is found to show the best performance. Our global min. search corroborates that most of the lowest-energy structures of Sin- (n = 14-20) clusters can be derived from assembling tricapped trigonal prisms in various ways. For most sizes previous structures are confirmed, whereas for Si20- a new structure has been found.
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115Zhao, J.; Huang, X.; Shi, R.; Liu, H.; Su, Y.; King, R. B. B28: The smallest all-boron cage from an ab initio global search. Nanoscale 2015, 7, 15086– 15090, DOI: 10.1039/C5NR04034EGoogle Scholar115https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlynsbzO&md5=32e05d6342b9a0da1fbb5be7e000fdd6B28: the smallest all-boron cage from an ab initio global searchZhao, Jijun; Huang, Xiaoming; Shi, Ruili; Liu, Hongsheng; Su, Yan; King, R. BruceNanoscale (2015), 7 (37), 15086-15090CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Our ab initio global searches reveal the lowest-energy cage for B28, which is built from two B12 units and prevails over the competing structural isomers such as planar, bowl, and tube. This smallest boron cage extends the scope of all-boron fullerene and provides a new structural motif of boron clusters and nanostructures.
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116Li, F.; Jin, P.; Jiang, D.-e.; Wang, L.; Zhang, S. B.; Zhao, J.; Chen, Z. B80 and B101–103 clusters: Remarkable stability of the core-shell structures established by validated density functionals. J. Chem. Phys. 2012, 136, 074302, DOI: 10.1063/1.3682776Google Scholar116https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XitlWmsbo%253D&md5=46fdb8f28ac0c4e3e42ac881eb8c35d4B80 and B101-103 clusters: Remarkable stability of the core-shell structures established by validated density functionalsLi, Fengyu; Jin, Peng; Jiang, De-en; Wang, Lu; Zhang, Shengbai B.; Zhao, Jijun; Chen, ZhongfangJournal of Chemical Physics (2012), 136 (7), 074302/1-074302/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Prompted by the very recent claim that the volleyball-shaped B80 fullerene is lower in energy than the B80 buckyball and core-shell structure, and inspired by the most recent finding of another core-shell isomer as the lowest energy B80 isomer, we carefully evaluated the performance of the d. functional methods in the energetics of boron clusters and confirmed that the core-shell construction (stuffed fullerene) is thermodynamically the most favorable structural pattern for B80. Our global min. search showed that both B101 and B103 also prefer a core-shell structure and that B103 can reach the complete core-shell configuration. We called for great attention to the theor. community when using d. functionals to investigate boron-related nanomaterials. (c) 2012 American Institute of Physics.
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117Olejniczak, A.; Cichy, B.; Stręk, W. DFT calculations of metal-organic I-III-VI semiconductor clusters: Benchmark of exchange-correlation functionals and localized basis sets. Comput. Mater. Sci. 2019, 163, 186– 195, DOI: 10.1016/j.commatsci.2019.03.036Google Scholar117https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlvFeksb4%253D&md5=ecd242602a277e38581361e9ec0b9cdbDFT calculations of metal-organic I-III-VI semiconductor clusters: Benchmark of exchange-correlation functionals and localized basis setsOlejniczak, Adam; Cichy, Bartlomiej; Strek, WieslawComputational Materials Science (2019), 163 (), 186-195CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)The primary objective of this work was to find the numerical methods suitable for DFT calcns. of ternary I-III-VI semiconductor quantum dots emerging as new functional materials which demonstrate an increasing need to comprehend their complex physicochem. properties. The benchmarking anal. of 8 exchange-correlation functionals and 11 basis sets including all-electron and effective core potential ones was performed. Four metal-org. mols., widely used as a single-precursor in the synthesis of A-In-X2 semiconductor quantum dots (A = Cu, Ag; X = S, Se) were considered as simple representatives of ternary semiconductor quantum dots. The geometrical parameters of the optimized structures were compared to the X-ray diffraction data. The hybrid PBE0 and B3PW91 functionals were found to be the best performing methods esp. when connected with cc-PVDZ or Def2-SVP basis sets. The methods widely used in the previous calcns. of II-VI semiconductor quantum dots, namely B3LYP functional and LANL2DZ or SBKJC basis sets, in this case resulted in lower agreement with the exptl. data.
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118Lousada, C. M.; Johansson, A. J.; Brinck, T.; Jonsson, M. Reactivity of metal oxide clusters with hydrogen peroxide and water–a DFT study evaluating the performance of different exchange–correlation functionals. Phys. Chem. Chem. Phys. 2013, 15, 5539– 5552, DOI: 10.1039/c3cp44559cGoogle Scholar118https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXkt1Gnsrw%253D&md5=aae4ff6dd76e2c755a726dd9bbf6c2f0Reactivity of metal oxide clusters with hydrogen peroxide and water - a DFT study evaluating the performance of different exchange-correlation functionalsLousada, Claudio M.; Johansson, Adam Johannes; Brinck, Tore; Jonsson, MatsPhysical Chemistry Chemical Physics (2013), 15 (15), 5539-5552CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We have performed a d. functional theory (DFT) investigation of the interactions of H2O2, H2O and HO radicals with clusters of ZrO2, TiO2 and Y2O3. Different modes of H2O adsorption onto the clusters were studied. In almost all the cases the dissociative adsorption is more exothermic than mol. adsorption. At the surfaces where H2O has undergone dissociative adsorption, the adsorption of H2O2 and the transition state for its decompn. are mediated by hydrogen bonding with the surface HO groups. Using the functionals B3LYP, B3LYP-D and M06 with clusters of 26 and 8 units of ZrO2, the M06 functional performed better than B3LYP in describing the reaction of decompn. of H2O2 and the adsorption of H2O. Addnl., we investigated clusters of the type (ZrO2)2, (TiO2)2 and (Y2O3) and the performance of the functionals B3LYP, B3LYP-D, B3LYP*, M06, M06-L, PBE0, PBE and PWPW91 in describing H2O2, H2O and HO√ adsorption and the energy barrier for decompn. of H2O2. The trends obtained for HO√ adsorption onto the clusters are discussed in terms of the ionization energy of the metal cation present in the oxide. In order to correctly account for the existence of an energy barrier for the decompn. of H2O2, the functional used must include Hartree-Fock exchange. Using minimal cluster models, the best performance in describing the energy barrier for H2O2 decompn. was obtained with the M06 and PBE0 functionals - the av. abs. deviations from expts. are 6 kJ mol-1 and 5 kJ mol-1 resp. With the M06 functional and a larger monoclinic (ZrO2)8 cluster model, the performance is in excellent agreement with exptl. data. For the different oxides, PBE0 was found to be the most effective functional in terms of performance and computational time cost.
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119Guo, L.; Zheng, X.; Zeng, Z.; Zhang, C. Spin orbital effect in lanthanides doped silicon cage clusters. Chem. Phys. Lett. 2012, 550, 134– 137, DOI: 10.1016/j.cplett.2012.08.076Google Scholar119https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVals7vL&md5=47c842c2b39fee40f5f7d24259ed539dSpin orbital effect in lanthanides doped silicon cage clustersGuo, Lingju; Zheng, Xiaohong; Zeng, Z.; Zhang, ChaoChemical Physics Letters (2012), 550 (), 134-137CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The stability of lanthanides (Ln) doped silicon cage clusters Ln@Si16 was studied using the DFT-PBE method. Fullerene-like Ln@Si16 structures are always more stable than Frank-Kasper structures, in contrast to transition metal doped Si16 clusters. By taking into account the spin-orbital coupling (SOC), some of the Ln@Si16 clusters show large total magnetic moments. The clusters with Pr, Nd, Sm and Tm have large orbital moments. The spin-orbit coupling effect may give useful information for further Stern-Gerlach magnetic deflection expts. and theor. simulations.
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120Li, T.; Feng, Z.; Jing, C.; Hong, F.; Cao, S.; Zhang, J. Importance of spin–orbit coupling in M@Pb12 clusters (M = 3d and 4d atoms).. Chem. Phys. Lett. 2012, 543, 106– 110, DOI: 10.1016/j.cplett.2012.06.034Google Scholar120https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFSrur3F&md5=c8f446cf785e1d2705407a7a3e907487Importance of spin-orbit coupling in M@Pb12 clusters (M = 3d and 4d atoms)Li, Tongwei; Feng, Zhenjie; Jing, Chao; Hong, Feng; Cao, Shixun; Zhang, JincangChemical Physics Letters (2012), 543 (), 106-110CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We investigated the effect of spin-orbit coupling (SOC) on symmetry and magnetism of M@Pb12 clusters (M = 3d and 4d transition-metal atoms) using the DFT-PBE method. The symmetry of geometrical configurations may be enhanced with SOC. The SOC marginally affects the local spin magnetic moments of 3d atoms encapsulated in the Pb12 cages, whereas for 4d series, the spin moments of most impurities will remarkably decrease when SOC is considered due to the strong hybridization between M-4d and Pb-6p states. The considerable orbital moments can be obtained. The variation trend of orbital moments can well be explained based on Hund's rule.
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121Sargolzaei, M.; Lotfizadeh, N. Spin and orbital magnetism of a single 3d transition-metal atom doped into icosahedral coinage-metal clusters X12 (X = Cu, Ag, Au). Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 83, 155404, DOI: 10.1103/PhysRevB.83.155404Google Scholar121https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXlsVynurw%253D&md5=38987f99a4b655d0d52fe4392707dacbSpin and orbital magnetism of a single 3d transition-metal atom doped into icosahedral coinage-metal clusters X12 (X=Cu, Ag, Au)Sargolzaei, Mahdi; Lotfizadeh, NedaPhysical Review B: Condensed Matter and Materials Physics (2011), 83 (15), 155404/1-155404/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors demonstrated the electronic structures and magnetic properties of single 3d transition metal (TM) atoms encapsulated in noble metal clusters with icosahedral symmetry in the framework of relativistic d. functional theory. Orbital polarization corrections were used to obtain an upper-estn. for orbital magnetic moments of all individual 3d atoms. The relativistic corrections are marginally affected the spin magnetic moments, whereas they induce significant orbital magnetism in TM@X12 icosahedra. A superat. picture has to be taken into account to explain the spin and orbital magnetism induced in TM@X12 icosahedron based on the Hund's rules.
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122Wales, D. J.; Doye, J. P. Global optimization by basin-hopping and the lowest energy structures of Lennard-Jones clusters containing up to 110 atoms. J. Phys. Chem. A 1997, 101, 5111– 5116, DOI: 10.1021/jp970984nGoogle Scholar122https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXktVGrurY%253D&md5=f40693ff24b5c84a8c482fa18ec1eb47Global Optimization by Basin-Hopping and the Lowest Energy Structures of Lennard-Jones Clusters Containing up to 110 AtomsWales, David J.; Doye, Jonathan P. K.Journal of Physical Chemistry A (1997), 101 (28), 5111-5116CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We describe a global optimization technique using "basin-hopping" in which the potential energy surface is transformed into a collection of interpenetrating staircases. This method has been designed to exploit the features that recent work suggests must be present in an energy landscape for efficient relaxation to the global min. The transformation assocs. any point in configuration space with the local min. obtained by a geometry optimization started from that point, effectively removing transition state regions from the problem. However, unlike other methods based upon hypersurface deformation, this transformation does not change the global min. The lowest known structures are located for all Lennard-Jones clusters up to 110 atoms, including a no. that have never been found before in unbiased searches.
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123Goedecker, S. Minima hopping: An efficient search method for the global minimum of the potential energy surface of complex molecular systems. J. Chem. Phys. 2004, 120, 9911– 9917, DOI: 10.1063/1.1724816Google Scholar123https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXktVehs7g%253D&md5=de03d696276ea3d433443c3139a674dfMinima hopping: An efficient search method for the global minimum of the potential energy surface of complex molecular systemsGoedecker, StefanJournal of Chemical Physics (2004), 120 (21), 9911-9917CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A method is presented that can find the global min. of very complex condensed matter systems. It is based on the simple principle of exploring the configurational space as fast as possible and of avoiding revisiting known parts of this space. Even though it is not a genetic algorithm, it is not based on thermodn. The efficiency of the method depends strongly on the type of moves that are used to hop into new local min. Moves that find low-barrier escape-paths out of the present min. generally lead into low energy min.
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124Heiles, S.; Johnston, R. L. Global optimization of clusters using electronic structure methods. Int. J. Quantum Chem. 2013, 113, 2091– 2109, DOI: 10.1002/qua.24462Google Scholar124https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnvVSiu7Y%253D&md5=91e62cbdee6f4d00a7d1e6ffa6315040Global optimization of clusters using electronic structure methodsHeiles, Sven; Johnston, Roy L.International Journal of Quantum Chemistry (2013), 113 (18), 2091-2109CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)A review. Over the past decade, there has been a significant growth in the development and application of methods for performing global optimization (GO) of cluster and nanoparticle structures using first-principles electronic structure methods coupled to sophisticated search algorithms. This has in part been driven by the desire to avoid the use of empirical potentials (EPs), esp. in cases where no reliable potentials exist to guide the search toward reasonable regions of configuration space. This has been facilitated by improvements in the reliability of the search algorithms, increased efficiency of the electronic structure methods, and the development of faster, multiprocessor high-performance computing architectures. In this review, we give a brief overview of GO algorithms, though concg. mainly on genetic algorithm and basin hopping techniques, first in combination with EPs. The major part of the review then deals with details of the implementation and application of these search methods to allow exploration for global min. cluster structures directly using electronic structure methods and, in particular, d. functional theory. Example applications are presented, ranging from isolated monometallic and bimetallic clusters to mol. clusters and ligated and surface supported metal clusters. Finally, some possible future developments are highlighted. © 2013 Wiley Periodicals, Inc.
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125Lyakhov, A. O.; Oganov, A. R.; Stokes, H. T.; Zhu, Q. New developments in evolutionary structure prediction algorithm USPEX. Comput. Phys. Commun. 2013, 184, 1172– 1182, DOI: 10.1016/j.cpc.2012.12.009Google Scholar125https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltlWgtg%253D%253D&md5=2e23099cbaa30f13f2c15bad849e144bNew developments in evolutionary structure prediction algorithm USPEXLyakhov, Andriy O.; Oganov, Artem R.; Stokes, Harold T.; Zhu, QiangComputer Physics Communications (2013), 184 (4), 1172-1182CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier B.V.)The authors present new developments of the evolutionary algorithm USPEX for crystal structure prediction and its adaptation to cluster structure prediction. To generate randomly sym. structures, and to introduce 'smart' variation operators, learning about preferable local environments. These and other developments substantially improve the efficiency of the algorithm and allow reliable prediction of structures with up to ∼200 atoms in the unit cell. An advanced version of the Particle Swarm Optimization (PSO) can be created from the authors' method, but PSO is strongly outperformed by USPEX. Also ideas from metadynamics can be used in the context of evolutionary structure prediction for escaping from local min. The authors' cluster structure prediction algorithm, using the ideas initially developed for crystals, also shows excellent performance and outperforms other state-of-the-art algorithms.
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126Zhao, J. J.; Shi, R. L.; Sai, L. W.; Huang, X. M.; Su, Y. Comprehensive genetic algorithm for ab initio global optimisation of clusters. Mol. Simul. 2016, 42, 809– 819, DOI: 10.1080/08927022.2015.1121386Google Scholar126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XlsFOntrY%253D&md5=e44ea50c1dd62073a1bd62a9858265b6Comprehensive genetic algorithm for ab initio global optimisation of clustersZhao, Jijun; Shi, Ruili; Sai, Linwei; Huang, Xiaoming; Su, YanMolecular Simulation (2016), 42 (10), 809-819CODEN: MOSIEA; ISSN:0892-7022. (Taylor & Francis Ltd.)A review. Cluster, as the aggregate of a few to thousands of atoms or mols., bridges the microscopic world of atoms and mols. and the macroscopic world of condensed matters. The phys. and chem. properties of a cluster are detd. by its ground state structure, which is significantly different from its bulk structure and sensitively relies on the cluster size. As a well-known nondeterministic polynomial-time hard problem, detg. the ground state structure of a cluster is a challenging task due to the extreme complexity of high-dimensional potential energy surface (PES). Genetic algorithm (GA) is an efficient global optimization method to explore the PES of clusters. Recently, we have developed a GA-based program, namely comprehensive genetic algorithm (CGA), and incorporated it with ab initio calcns. Using this program, the lowest energy structures of a variety of elemental and compd. clusters with different types of chem. bonding have been detd., and their phys. properties have been investigated and compared with exptl. data. In this article, we will describe the technique details of CGA program and present an overview of its successful applications.
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127Shang, C.; Liu, Z.-P. Stochastic surface walking method for structure prediction and pathway searching. J. Chem. Theory Comput. 2013, 9, 1838– 1845, DOI: 10.1021/ct301010bGoogle Scholar127https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFOlt7c%253D&md5=ff2585b886e8cc63d4443934f5317048Stochastic Surface Walking Method for Structure Prediction and Pathway SearchingShang, Cheng; Liu, Zhi-PanJournal of Chemical Theory and Computation (2013), 9 (3), 1838-1845CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)We propose an unbiased general-purpose potential energy surface (PES) searching method for both the structure and the pathway prediction of a complex system. The method is based on the idea of bias-potential-driven dynamics and Metropolis Monte Carlo. A central feature of the method is able to perturb smoothly a structural configuration toward a new configuration and simultaneously has the ability to surmount the high barrier in the path. We apply the method for locating the global min. (GM) of short-ranged Morse clusters up to 103 atoms starting from a random structure without using extra information from the system. In addn. to GM searching, the method can identify the pathways for chem. reactions with large dimensionality, as demonstrated in a nanohelix transformation contg. 222 degrees of freedoms.
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128Lv, J.; Wang, Y.; Zhu, L.; Ma, Y. Particle-swarm structure prediction on clusters. J. Chem. Phys. 2012, 137, 084104, DOI: 10.1063/1.4746757Google Scholar128https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xht1CgtLzP&md5=8a1a3cd99ae1c2bec4f2d258d509c253Particle-swarm structure prediction on clustersLv, Jian; Wang, Yanchao; Zhu, Li; Ma, YanmingJournal of Chemical Physics (2012), 137 (8), 084104/1-084104/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We developed an efficient method for cluster structure prediction based on the generalization of particle swarm optimization (PSO). A local version of PSO algorithm was implemented to utilize a fine exploration of potential energy surface for a given non-periodic system. We specifically devised a technique of so-called bond characterization matrix (BCM) to allow the proper measure on the structural similarity. The BCM technique was then employed to eliminate similar structures and define the desirable local search spaces. The introduction of point group symmetries into generation of cluster structures enables structural diversity and apparently avoids the generation of liq.-like (or disordered) clusters for large systems, thus considerably improving the structural search efficiency. We incorporated Metropolis criterion into our method to further enhance the structural evolution towards low-energy regimes of potential energy surfaces. Our method was extensively benchmarked on Lennard-Jones clusters with different sizes up to 150 atoms and applied into prediction of new structures of medium-sized Lin (n = 20, 40, 58) clusters. High search efficiency was achieved, demonstrating the reliability of the current methodol. and its promise as a major method on cluster structure prediction. (c) 2012 American Institute of Physics.
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129Lewis, G. N. The atom and the molecule. J. Am. Chem. Soc. 1916, 38, 762– 785, DOI: 10.1021/ja02261a002Google Scholar129https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaC28XlvFSl&md5=9f8b4fdf6c255a1c60dafaad766c9d3aThe atom and the moleculeLewis, G. N.Journal of the American Chemical Society (1916), 38 (), 762-85CODEN: JACSAT; ISSN:0002-7863.cf. C. A. 71 3865 and Bray and Branch, C. A. 7, 3865. Compds. should be classed as polar and nonpolar rather than inorg. and org. These classes are roughly the same. A nonpolar mol. is one in which the electrons belonging to the individual atom are held by such restraints that they do not move far from their normal positions, while in the polar mols. the electrons, being more mobile, so move as to sep. the mol. into positive and negative parts. In an extremely polar mol. such as NaCl it is probable that in the great majority of the mols. the Cl atom has acquired a unit negative charge and therefore the Na atom a unit positive charge, and the process of ionization probably consists only in a further sepn. of these charged parts. If a weakly polar mol. comes into the neighborhood of a more polar one it becomes itself more polar. In this process the weaker bipole stretches and its moment increases. A "cubical atom" is proposed as a basis of a new theory of atomic structure. Thus Li is a cube with a single electron on one corner, Be has 2 electrons, B 3, C 4, N 5, O 6, and F 7. This view is in harmony with the theory developed by Parson, C. A. 10, 406. An atom is considered as having an unalterable kernel which possesses an excess of positive charges corresponding in number to the ordinal number of the group in the periodic table to which the element belongs (cf. Thomson, C. A. 8, 824). There is a shell of electrons around the kernel which, in the case of a neutral atom, contains negative electrons equal in number to the excess of positive charges of the kernel, but the number of electrons in the shell may vary during chem. changes between zero and 8. The atom tends to hold an even number of electrons in the shell (especially 8 at the corners of the cube) but the electrons may ordinarily pass from one position to another in this shell. Two atomic shells are mutually interpenetrable. The paper is a discussion of these ideas applied to the structure of atoms and compds.
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130Langmuir, I. Types of valence. Science 1921, 54, 59– 67, DOI: 10.1126/science.54.1386.59Google Scholar130https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaB3MXhvFWqsg%253D%253D&md5=ec20c36dc54a6fdb48f37c579b6c4579Types of valenceLangmuir, IrvingScience (Washington, DC, United States) (1921), 54 (), 59-67CODEN: SCIEAS; ISSN:0036-8075.Three postulates are made. They are consistent with those previously proposed by L. in the Lewis-Langmuir theory of at. structure. This new method of deriving the relation of structure of the atom and types of valence is very much simpler. New ideas of the relationship between the different types of valence are brought out. Compds. are classified according to the types of valence of their atoms into (1) complete compds., (2) incomplete compds., (3) exceptional cases. The theory accounts for the structure of the first two classes of compds. This is an important paper in the development of the at. structure theory.
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131Pyykkö, P. Understanding the eighteen-electron rule. J. Organomet. Chem. 2006, 691, 4336– 4340, DOI: 10.1016/j.jorganchem.2006.01.064Google ScholarThere is no corresponding record for this reference.
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132Dognon, J. P.; Clavaguéra, C.; Pyykkö, P. Towards a 32-electron principle: Pu@Pb12 and related systems. Angew. Chem., Int. Ed. 2007, 46, 1427– 1430, DOI: 10.1002/anie.200604198Google Scholar132https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXitleisLk%253D&md5=0d4b8d077fd40404adbaf2832f3b8730Towards a 32-electron principle: Pu@Pb12 and related systemsDognon, Jean-Pierre; Clabaguera, Carine; Pyykko, PekkaAngewandte Chemie, International Edition (2007), 46 (9), 1427-1430CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The predicted endohedral icosahedral clusters Pu@Pb12 and [Am@Pb12]+ have an outermost 32-electron system corresponding to formally occupied 7s, 7p, 6d, and 5f actinide orbitals, each of which interacts with a Pb 6p-based orbital of the [Pb12]2- cage. This study provides the first example of a formal 32-electron principle, and 32 is not a false magic no. Data are presented also on Pb122-, Yb@Pb12, [Th@Pb12]4-, [U@Pb12]2-, [Np@Pb12]-, and [Cm@Pb12]2+.
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133Hirsch, A.; Chen, Z.; Jiao, H. Spherical aromaticity in Ih symmetrical fullerenes: The 2(N+1)2 rule. Angew. Chem., Int. Ed. 2000, 39, 3915– 3917, DOI: 10.1002/1521-3773(20001103)39:21<3915::AID-ANIE3915>3.0.CO;2-OGoogle Scholar133https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXotF2jsL4%253D&md5=88f0ed0ac5ad731533a40dbe08d91145Spherical aromaticity in Ih symmetrical fullerenes: The 2(N+1)2 ruleHirsch, Andreas; Chen, Zhongfang; Jiao, HaijunAngewandte Chemie, International Edition (2000), 39 (21), 3915-3917CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)The authors demonstrate that the total diatropy of icosahedral fullerenes such as C20, C60, and C80, and their cluster distortion depend on the degree of the electron occupation in the valence shell. The resulting 2(N+1)2 rule for spherical aromaticity represents the spherical analog to the 4N+2 rule for the cyclic annulenes.
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134Chen, Z.; Jiao, H.; Hirsch, A.; Thiel, W. The 2(N+1)2 rule for spherical aromaticity: further validation. J. Mol. Model. 2001, 7, 161– 163, DOI: 10.1007/s008940100021Google Scholar134https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXms1OitLw%253D&md5=542548d93400d69d55e22b2782a8fb5dThe 2(N+1)2 rule for spherical aromaticity: further validationChen, Zhongfang; Jiao, Haijun; Hirsch, Andreas; Thiel, WalterJournal of Molecular Modeling [online computer file] (2001), 7 (5), 161-163CODEN: JMMOFK; ISSN:0948-5023. (Springer-Verlag)Max. spherical aromaticity occurs in icosahedral fullerenes when the valence π-shells are completely filled with 2(N+1)2 electrons. Ab initio calcns. of nucleus-independent chem. shifts show that this rule can also be applied to less sym. small fullerenes and H clusters.
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135Hückel, E. Quantentheoretische beiträge zum benzolproblem. Eur. Phys. J. A 1931, 70, 204– 286, DOI: 10.1007/BF01339530Google ScholarThere is no corresponding record for this reference.
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136Chen, Z.; Wannere, C. S.; Corminboeuf, C.; Puchta, R.; Schleyer, P. V. R. Nucleus-independent chemical shifts (NICS) as an aromaticity criterion. Chem. Rev. 2005, 105, 3842– 3888, DOI: 10.1021/cr030088+Google Scholar136https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVGisrbF&md5=85a30c551bbbc0439ceab177216a14e3Nucleus-Independent Chemical Shifts (NICS) as an Aromaticity CriterionChen, Zhongfang; Wannere, Chaitanya S.; Corminboeuf, Clemence; Puchta, Ralph; Schleyer, Paul von RagueChemical Reviews (Washington, DC, United States) (2005), 105 (10), 3842-3888CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A comprehensive review is presented on nucleus-independent chem. shift as a criterion for aromaticity.
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137Hirsch, A.; Chen, Z.; Jiao, H. Spherical aromaticity of inorganic cage molecules. Angew. Chem., Int. Ed. 2001, 40, 2834– 2838, DOI: 10.1002/1521-3773(20010803)40:15<2834::AID-ANIE2834>3.0.CO;2-HGoogle Scholar137https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXmt1Wlsrs%253D&md5=9ab32d3386a23bd44d10c45fa36e0828Spherical aromaticity of inorganic cage moleculesHirsch, Andreas; Chen, Zhongfang; Jiao, HaijunAngewandte Chemie, International Edition (2001), 40 (15), 2834-2838CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)Recently the authors (ibidem 2000) demonstrated that the icosahedral fullerenes C20, C60, and C80 reach their max. spherical aromaticity if their π shells are completely filled. This treatment of spherical aromaticity is extended to a set of well-known inorg. cage compds., for which it is demonstrated that they are highly arom. because of the closed-shell nature of both their σ and π systems. The optimized bond lengths and nucleus-independent chem. shifts (NICS) were calcd. for the tetrahedral E4 clusters (E = N, P, As, Sb, and Bi), the E3H3 rings, and HE4+ with C3v symmetry. The same is done for the tetrahedral cluster ions E44- (E = Si, Ge, Sn, and Pb) as well as for the E94- (E = Si, Ge, Sn, Pb) and Bi95+ species with D3h and C4v symmetry, and the E92- (E = Ge, Sn, Pb) clusters and Bi97+ with D3h symmetry. In contrast to the fullerenes, the HOMOs within the highly sym. inorg. cage compds. are σ orbitals. The spherical (2Nπ + 1)2 aromaticity of the fullerenes is reached when the π shells are filled. The double spherical aromaticity of the inorg. cage compds. is also a consequence of the complete filling of the corresponding shells, but, here, the whole π and σ systems are involved.
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138Clemenger, K. Ellipsoidal shell structure in free-electron metal clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1985, 32, 1359– 1362, DOI: 10.1103/PhysRevB.32.1359Google Scholar138https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXkslyrtrk%253D&md5=9cf05451bd6b6a0ecafe77d0c67d935fEllipsoidal shell structure in free-electron metal clustersClemenger, KeithPhysical Review B: Condensed Matter and Materials Physics (1985), 32 (2), 1359-62CODEN: PRBMDO; ISSN:0163-1829.The possibility of ellipsoidal distortions in free-electron metal clusters, analogous to the shape variations among at. nuclei, was investigated with the use of a modified Nilsson Hamiltonian. In most cases, the predicted equil. shape is ellipsoidal rather than spherical, so that the spherical shells are divided into ellipsoidal subshells. A strong correlation was obsd. between the energy-level sequence of these subshells and the sequence of peaks in alkali-metal cluster mass spectra, indicating that metal clusters generally assume approx. ellipsoidal shapes.
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139Wade, K. The structural significance of the number of skeletal bonding electron-pairs in carboranes, the higher boranes and borane anions, and various transition-metal carbonyl cluster compounds. J. Chem. Soc. D 1971, 792– 793, DOI: 10.1039/c29710000792Google Scholar139https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE3MXkvFylsrs%253D&md5=977fd8681f8e0d395283e8e53b798064Structural significance of the number of skeletal bonding electron-pairs in carboranes, the higher boranes, and borane anions, and various transition metal carbonyl cluster compoundsWade, K.Journal of the Chemical Society [Section] D: Chemical Communications (1971), (15), 792-3CODEN: CCJDAO; ISSN:0577-6171.The skeletal structures of carboranes, the higher boranes and borane anions, and transition metal carbonyl cluster compds. [e.g., Ru6(CO)182-, Fe5(CO)15C, and Fe3(CO)9S2] are related to the no. of skeletal bonding electron pairs they contain; species with n skeletal atoms adopt closo structures if held together by (n + 1) pairs, nido structures if held together by (n + 2) pairs, and arachno structures if held together by (n + 3) pairs of skeletal bonding electrons.
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140Mingos, D. M. P. Polyhedral Skeletal Electron Pair Approach. Acc. Chem. Res. 1984, 17, 311– 319, DOI: 10.1021/ar00105a003Google Scholar140https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXltlOisb8%253D&md5=0587a193864cbb8a00468579c76ccb56Polyhedral skeletal electron pair approachMingos, D. Michael P.Accounts of Chemical Research (1984), 17 (9), 311-19CODEN: ACHRE4; ISSN:0001-4842.A review with numerous refs. with discussion of polyhedral mol. structures and their electron configurations.
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141Mingos, D. M. P.; Slee, T.; Zhenyang, L. Bonding models for ligated and bare clusters. Chem. Rev. 1990, 90, 383– 402, DOI: 10.1021/cr00100a003Google Scholar141https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXhsVGlurw%253D&md5=4fe459738498ba6eb5dd5b0bffb67645Bonding models for ligated and bare clustersMingos, D. Mike P.; Slee, Tom; Zhenyang, LinChemical Reviews (Washington, DC, United States) (1990), 90 (2), 383-402CODEN: CHREAY; ISSN:0009-2665.A review with 130 refs. of theor. methods applicable to gas-phase bare clusters and condensed-phase ligated clusters. The jellium and LCAO approaches are compared and the application of electron-counting rules to mol.-beam clusters is discussed.
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142Duncan, M. A. Invited review article: laser vaporization cluster sources. Rev. Sci. Instrum. 2012, 83, 041101, DOI: 10.1063/1.3697599Google Scholar142https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XlsVaisL0%253D&md5=2e77e119fbd87aaf5be7b9b757790326Invited Review Article: Laser vaporization cluster sourcesDuncan, Michael A.Review of Scientific Instruments (2012), 83 (4), 041101/1-041101/19CODEN: RSINAK; ISSN:0034-6748. (American Institute of Physics)A review. The laser vaporization cluster source was used for the prodn. of gas phase at. clusters and metal-mol. complexes for 30 years. Numerous expts. in the chem. and physics of clusters have employed this source. Its operation is simple in principle, but there are many subtle design features that influence the no. and size of clusters produced, as well as their compn., charge state, and temp. This article examines all aspects of the design of these cluster sources, discussing the relevant chem., physics, and mech. aspects of exptl. configurations employed by different labs. The principles detailed here provide a framework for the design and implementation of this source for new applications. (c) 2012 American Institute of Physics.
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143Cox, D.; Trevor, D.; Whetten, R.; Rohlfing, E.; Kaldor, A. Aluminum clusters: Magnetic properties. J. Chem. Phys. 1986, 84, 4651– 4656, DOI: 10.1063/1.449991Google Scholar143https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XitlGkur0%253D&md5=806a8f69f95348a65b48ef3d0645fb1cAluminum clusters: magnetic propertiesCox, D. M.; Trevor, D. J.; Whetten, R. L.; Rohlfing, E. A.; Kaldor, A.Journal of Chemical Physics (1986), 84 (8), 4651-6CODEN: JCPSA6; ISSN:0021-9606.The magnetic moments were measured of gas-phase Al clusters ranging in size from 2 to 25 atoms. Al clusters were produced by pulsed-laser vaporization of an Al rod inside the throat of a high-pressure pulsed nozzle. Al clusters <9 atoms in size have magnetic moments generally consistent with those predicted from spin and orbital moments of the ground electronic states. As expected, a general trend toward reduced magnetic moment per atom with increasing cluster size is obsd.
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144Kumar, V. Structure and electronic properties of Al14 and Al13Na clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1998, 57, 8827– 8829, DOI: 10.1103/PhysRevB.57.8827Google Scholar144https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXisVGju7k%253D&md5=e353a921dc2b33995310e98e7886f4cdStructure and electronic properties of Al14 and Al13Na clustersKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (1998), 57 (15), 8827-8829CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio mol. dynamics simulations on the Al14 cluster show that in the capped icosahedron structure of this cluster, the 3s electrons of the capping Al atom behave more like core electrons, giving rise to an electronic shell closure effect known for simple metal clusters with 40 valence electrons and which we also find for Al13Na. This makes the two clusters magic. Al14 has a higher binding energy than Al13. However, the HOMO-LUMO gap in Al14 is lower than in Al13 whereas in the case of Al13Na it increases. These results are in complete agreement with the observation of a lower ionization potential for Al14 and a higher ionization potential for Al13Na.
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145Jarrold, M. F.; Bower, J. E. The reactions of mass selected aluminum cluster ions, Al+n (n = 4–25), with oxygen. J. Chem. Phys. 1986, 85, 5373– 5375, DOI: 10.1063/1.451157Google Scholar145https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXhtF2hsg%253D%253D&md5=0f8b066d88b01f14d6db36bba8efc831The reactions of mass selected aluminum cluster ions, Aln+ (n = 4-25), with oxygenJarrold, Martin F.; Bower, J. EricJournal of Chemical Physics (1986), 85 (9), 5373-5CODEN: JCPSA6; ISSN:0021-9606.The reactions were studied of mass selected Aln+ (n = 4-25) with O2. The products and unreacted ions were analyzed with a quadrupole mass spectrometer. E.g. Al16+ gave Al12+ (90%) and Al11+ (10%) as detectable ions. No O-contg. product ions were obsd. for any of the clusters studied; the significance of this result is discussed.
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146Thomas, O. C.; Zheng, W.; Bowen, K. H., Jr Magic numbers in copper-doped aluminum cluster anions. J. Chem. Phys. 2001, 114, 5514– 5519, DOI: 10.1063/1.1349547Google Scholar146https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXitFKltrg%253D&md5=1615c636392710c8ffb98627a4da35dbMagic numbers in copper-doped aluminum cluster anionsThomas, Owen C.; Zheng, Weijun; Bowen, Kit H., Jr.Journal of Chemical Physics (2001), 114 (13), 5514-5519CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Copper-doped aluminum cluster anions, CuAln- were generated in a laser vaporization source and examd. via mass spectrometry (n=2-30) and anion photoelectron spectroscopy (n=2-15). The mass spectrum of the CuAln- series is dominated by CuAl13- with other magic nos. also appearing at n=6, 19, and 23. The electron affinity vs. cluster size trend shows a peak at n=6 and a dip at n=13. These results are discussed in terms of the reordering of shell model energy levels and the enhanced stability of neutral CuAl13. Reordering, which is a consequence of the copper atom residing in the central region of these clusters, provides an anion-oriented electronic rationale for the obsd. magic nos.
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147Taylor, K.; Pettiette, C.; Craycraft, M.; Chesnovsky, O.; Smalley, R. Ups of negative aluminum clusters. Chem. Phys. Lett. 1988, 152, 347– 352, DOI: 10.1016/0009-2614(88)80104-0Google Scholar147https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXkslygsQ%253D%253D&md5=49af372eb02d11473b4481ca8a687f3bUPS of negative aluminum clustersTaylor, K. J.; Pettiette, C. L.; Craycraft, M. J.; Chesnovsky, O.; Smalley, R. E.Chemical Physics Letters (1988), 152 (4-5), 347-52CODEN: CHPLBC; ISSN:0009-2614.UPS of neg. Al clusters in the size range of 3-32 atoms is presented. The clusters were prepd. in a supersonic beam by laser vaporization, and an ArF excimer laser (6.42 eV) was used for photodetachment. The electron affinities of the neutral clusters are peaked at cluster sizes of 6, 13, 19, and 23, which is consistent with a shell model of electronic structure. A size-dependent increase in the photoelectron yield at 5 eV binding energy in the UPS data was interpreted as the merging of the 3s and 3p valence bands.
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148Ma, L.; v. Issendorff, B.; Aguado, A. Photoelectron spectroscopy of cold aluminum cluster anions: Comparison with density functional theory results. J. Chem. Phys. 2010, 132, 104303, DOI: 10.1063/1.3352445Google Scholar148https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjt1aksbo%253D&md5=a65ea3e26a779a8da80e0134565e0b5cPhotoelectron spectroscopy of cold aluminum cluster anions: comparison with density functional theory resultsMa, Lei; von Issendorff, Bernd; Aguado, AndresJournal of Chemical Physics (2010), 132 (10), 104303/1-104303/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Photoelectron spectra of cold Al cluster anions Aln- were measured in the size range n = 13-75 and are compared to the results of d. functional theory calcns. Good agreement between the measured spectra and the calcd. d. of states is obtained for most sizes, which gives strong evidence that the correct structures were found. In particular the results confirm the occurrence of rather different structural motifs in this size range, from fcc.-like stacks over fragments of decahedrons to disordered structures. An anal. of the d. of states of representatives of the different structural motifs shows that the electronic structure is strongly influenced by the cluster geometry, and that a clear jelliumlike electron shell structure is present only in some exceptional cases. (c) 2010 American Institute of Physics.
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149Bergeron, D. E.; Castleman, A. W.; Morisato, T.; Khanna, S. N. Formation of Al13I-: Evidence for the superhalogen character of Al13. Science 2004, 304, 84– 87, DOI: 10.1126/science.1093902Google Scholar149https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXis1antro%253D&md5=1b0840ceb9dd79895511c15613508d98Formation of Al13I-: Evidence for the Superhalogen Character of Al13Bergeron, Denis E.; Castleman, A. Welford, Jr.; Morisato, Tsuguo; Khanna, Shiv N.Science (Washington, DC, United States) (2004), 304 (5667), 84-87CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Al13- is a cluster known for the pronounced stability that arises from coincident closures of its geometric and electronic shells. We present exptl. evidence for a very stable cluster corresponding to Al13I-. Ab initio calcns. show that the cluster features a structurally unperturbed Al13- core and a region of high charge d. on the aluminum vertex opposite from the iodine atom. This ionically bound magic cluster can be understood by considering that Al13 has an electronic structure reminiscent of a halogen atom. Comparisons to polyhalides provide a sound explanation for our chem. observations.
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150Kambe, T.; Haruta, N.; Imaoka, T.; Yamamoto, K. Solution-phase synthesis of Al13– using a dendrimer template. Nat. Commun. 2017, 8, 2046, DOI: 10.1038/s41467-017-02250-4Google Scholar150https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MzgsVWgtw%253D%253D&md5=a096ecdf7e092b8de4684962e2ab8593Solution-phase synthesis of Al13(-) using a dendrimer templateKambe Tetsuya; Imaoka Takane; Yamamoto Kimihisa; Kambe Tetsuya; Haruta Naoki; Imaoka Takane; Yamamoto Kimihisa; Imaoka TakaneNature communications (2017), 8 (1), 2046 ISSN:.Superatoms, clusters that mimic the properties of elements different to those of which they are composed, have the potential to serve as building blocks for unprecedented materials with tunable properties. The development of a method for the solution-phase synthesis of superatoms would be an indispensable achievement for the future progress of this research field. Here we report the fabrication of aluminum clusters in solution using a dendrimer template, producing Al13(-), which is the most well-known superatom. The Al13(-) cluster is identified using mass spectrometry and scanning transmission electron microscopy, and X-ray photoelectron spectroscopy is used to measure the binding energies. The superatomic stability of Al13(-) is demonstrated by evaluating its tendency toward oxidation. In addition, the synthesis of Al13(-) in solution enables electrochemical measurements, the results of which suggest oxidation of Al13(-). This solution-phase synthesis of Al13(-) superatoms has a significant role for the experimental development of cluster science.
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151Ko, Y. J.; Shakya, A.; Wang, H.; Grubisic, A.; Zheng, W.; Götz, M.; Ganteför, G.; Bowen, K. H.; Jena, P.; Kiran, B. Electronic structure and properties of isoelectronic magic clusters: Al13X (X = H, Au, Li, Na, K, Rb, Cs). J. Chem. Phys. 2010, 133, 124308, DOI: 10.1063/1.3490401Google Scholar151https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht1Slur3F&md5=3f5da6fce491c6afe3d7d88caf1021e4Electronic structure and properties of isoelectronic magic clusters: Al13X (X=H,Au,Li,Na,K,Rb,Cs)Ko, Yeon Jae; Shakya, Anisha; Wang, Haopeng; Grubisic, Andrej; Zheng, Weijun; Goetz, Matthias; Gantefoer, Gerd; Bowen, Kit H.; Jena, Puru; Kiran, BoggavarapuJournal of Chemical Physics (2010), 133 (12), 124308/1-124308/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The equil. structure, stability, and electronic properties of the Al13X (X = H,Au,Li,Na,K,Rb,Cs) clusters have been studied using a combination of photoelectron spectroscopy expt. and d. functional theory. All these clusters constitute 40 electron systems with 39 electrons contributed by the 13 Al atoms and 1 electron contributed by each of the X (X = H,Au,Li,Na,K,Rb,Cs) atom. A systematic study allows us to investigate whether all electrons contributed by the X atoms are alike and whether the structure, stability, and properties of all the magic clusters are similar. Furthermore, quant. agreement between the calcd. and the measured electron affinities and vertical detachment energies enable us to identify the ground state geometries of these clusters both in neutral and anionic configurations. (c) 2010 American Institute of Physics.
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152Khanna, S.; Jena, P. Assembling crystals from clusters. Phys. Rev. Lett. 1992, 69, 1664– 1667, DOI: 10.1103/PhysRevLett.69.1664Google Scholar152https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XlvFyqsbc%253D&md5=0aed03f093b373861ea47cf02638bb2eAssembling crystals from clustersKhanna, S. N.; Jena, P.Physical Review Letters (1992), 69 (11), 1664-7CODEN: PRLTAO; ISSN:0031-9007.The stability of a cluster can be substantially enhanced by changing its size and/or compn. so as to take advantage of the electronic shell filling as well as close at. packing. The interaction between two such clusters is found to be weak and can form the basis for synthesizing a new class of cluster-assembled crystals with uncommon properties.
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153Nakajima, A.; Kishi, T.; Sugioka, T.; Kaya, K. Electronic and geometric structures of aluminum-boron negative cluster ions (AlnB–m). Chem. Phys. Lett. 1991, 187, 239– 244, DOI: 10.1016/0009-2614(91)90419-AGoogle ScholarThere is no corresponding record for this reference.
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154Smith, J. C.; Reber, A. C.; Khanna, S. N.; Castleman, A., Jr Boron substitution in aluminum cluster anions: Magic clusters and reactivity with oxygen. J. Phys. Chem. A 2014, 118, 8485– 8492, DOI: 10.1021/jp501934tGoogle Scholar154https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXlvFCrtrw%253D&md5=7755f0dc2abda2852399a9f0125f8b42Boron Substitution in Aluminum Cluster Anions: Magic Clusters and Reactivity with OxygenSmith, Jordan C.; Reber, Arthur C.; Khanna, Shiv N.; Castleman, A. W.Journal of Physical Chemistry A (2014), 118 (37), 8485-8492CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We have studied the size-selective reactivity of AlnBm- clusters m = 1,2 with O2 to investigate the effect of congener substitution in energetic aluminum clusters. Mixed-metal clusters offer an addnl. strategy for tuning the electronic and geometric structure of clusters and by substituting an atom with a congener; we may investigate the effect of structural changes in clusters with similar electronic structures. Using a fast-flow tube mass spectrometer, we formed aluminum boride cluster anions and exposed them to mol. oxygen. We found multiple stable species with Al12B- and Al11B2- being highly resistant to reactivity with oxygen. These clusters behave in a similar manner as Al13-, which has previously been found to be stable in oxygen because of its icosahedral geometry and its filled electronic shell. Al13- and Al12B- have icosahedral structures, while Al11B2- forms a distorted icosahedron. All three of these clusters have filled electronic shells, and Al12B- has a larger HOMO-LUMO gap due to its compact geometry. Other cluster sizes are investigated, and the structures of the AlnB- series (n = 5-16) are found to have endohedrally doped B atoms, as do many of the AlnB2- (n = 4 - 15) clusters. The primary etching products are found to be a loss of two Al2O mols., with boron likely to remain in the cluster.
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155Pal, R.; Cui, L.-F.; Bulusu, S.; Zhai, H.-J.; Wang, L.-S.; Zeng, X. C. Probing the electronic and structural properties of doped aluminum clusters: MAl12– (M = Li, Cu, and Au). J. Chem. Phys. 2008, 128, 024305, DOI: 10.1063/1.2805386Google Scholar155https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosVKruw%253D%253D&md5=3da0ed0aa40cfe8976c4370939804582Probing the electronic and structural properties of doped aluminum clusters: MAl12- (M = Li, Cu, and Au)Pal, R.; Cui, Li-Feng; Bulusu, S.; Zhai, Hua-Jin; Wang, Lai-Sheng; Zeng, X. C.Journal of Chemical Physics (2008), 128 (2), 024305/1-024305/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Photoelectron spectroscopy (PES) is combined with theor. calcns. to study the electronic and at. structures of 3 doped Al clusters, MAl12- (M = Li, Cu, and Au). Well-resolved PES spectra were obtained at 2 detachment photon energies, 266 nm (4.661 eV) and 193 nm (6.424 eV). Basin-hopping global optimization method in combination with d.-functional theory calcns. was used for the structural searches. Good agreement between the measured PES spectra and theor. simulations helps to identify the global min. structures. LiAl12- (C5v) can be viewed as replacing a surface Al atom by Li on an icosahedral Al13-, whereas Cu prefers the central site to form the encapsulated D3d-Cu@Al12-. For AuAl12- (C1), Au also prefers the central site, but severely distorts the Al12 cage due to its large size. (c) 2008 American Institute of Physics.
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156Kawamata, H.; Negishi, Y.; Nakajima, A.; Kaya, K. Electronic properties of substituted aluminum clusters by boron and carbon atoms (AlnBm–/AlnCm–); new insights into s–p hybridization and perturbed shell structures. Chem. Phys. Lett. 2001, 337, 255– 262, DOI: 10.1016/S0009-2614(01)00198-1Google Scholar156https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXisFGmsLk%253D&md5=bd897c41f45aab0e29d67efaad462ec6Electronic properties of substituted aluminum clusters by boron and carbon atoms (AlnBm-/AlnCm-); new insights into s-p hybridization and perturbed shell structuresKawamata, H.; Negishi, Y.; Nakajima, A.; Kaya, K.Chemical Physics Letters (2001), 337 (4,5,6), 255-262CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Substituted Al clusters with B atom, which is trivalent but smaller than Al atom, or with covalent C atom were investigated using photoelectron spectroscopy (PES). In Aln-mBm- (n ≥ 5 for m = 1, n ≥ 10 for m = 2), three valence electrons of each B atom as well as Al atom contribute to electron shell structures, while the C atom strongly binds two free electrons from Aln- in AlnC- (n = 5-30). The substitution with B atom allowed us to det. that s-p mixing starts at n = 6 in pure Al clusters. Perturbed electron shells and the geometry of Al12B1-, Al11B2-, and Al12C- are discussed.
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157Lang, S. M.; Claes, P.; Neukermans, S.; Janssens, E. Cage structure formation of singly doped aluminum cluster cations AlnTM+(TM= Ti, V, Cr). J. Am. Soc. Mass Spectrom. 2011, 22, 1508, DOI: 10.1007/s13361-011-0181-1Google Scholar157https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFaqs7fF&md5=7d5807e1cab8589a35a863443d295e20Cage structure formation of singly doped aluminum cluster cations AlnTM+ (TM = Ti, V, Cr)Lang, Sandra M.; Claes, Pieterjan; Neukermans, Sven; Janssens, EwaldJournal of the American Society for Mass Spectrometry (2011), 22 (9), 1508-1514CODEN: JAMSEF; ISSN:1044-0305. (Springer)Structural information on free transition metal doped aluminum clusters, AlnTM+ (TM = Ti, V, Cr), was obtained by studying their ability for argon physisorption. Systematic size (n = 5 - 35) and temp. (T = 145 - 300 K) dependent investigations reveal that bare Aln+ clusters are inert toward argon, while AlnTM+ clusters attach one argon atom up to a crit. cluster size. This size is interpreted as the geometrical transition from surface-located dopant atoms to endohedrally doped aluminum clusters with the transition metal atom residing in an aluminum cage. The crit. size, ncrit, is found to be surprisingly large, namely ncrit = 16 and ncrit = 19 - 21 for TM = V, Cr, and TM = Ti, resp. Exptl. cluster-argon bond dissocn. energies were derived as function of cluster size from equil. mass spectra and are in the 0.1-0.3 eV range.
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158Akutsu, M.; Koyasu, K.; Atobe, J.; Miyajima, K.; Mitsui, M.; Tsunoyama, H.; Nakajima, A. Geometric and electronic properties of Si-atom doped Al clusters: robustness of binary superatoms against charging. Phys. Chem. Chem. Phys. 2017, 19, 20401– 20411, DOI: 10.1039/C7CP03409AGoogle Scholar158https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFCit7zP&md5=cea4af432850699dd1d8e10b1668e23eGeometric and electronic properties of Si-atom doped Al clusters: robustness of binary superatoms against chargingAkutsu, Minoru; Koyasu, Kiichirou; Atobe, Junko; Miyajima, Ken; Mitsui, Masaaki; Tsunoyama, Hironori; Nakajima, AtsushiPhysical Chemistry Chemical Physics (2017), 19 (31), 20401-20411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The geometric and electronic properties of silicon-atom-doped aluminum clusters, AlnSim (n = 7-30, m = 0-2), were investigated exptl. The size dependences of the ionization energy and electron affinity of AlnSim show that the stability of AlnSim is governed by the total no. of valence electrons in the clusters, where Al and Si atoms behave as trivalent and tetravalent atoms, resp. Together with theor. calcns., it has been revealed that neutral Al10Si and Al12Si have a cage-like geometry with central Si atom encapsulation and closed electronic structures of superat. orbitals (SAOs), and also that they both exhibit geometric robustness against reductive and oxidative changes as cage-like binary superatoms of Si@Al10 and Si@Al12. As well as the single-atom-doped binary superatoms, the effect of symmetry lowering was examd. by doping a second Si atom toward the electron SAO closing of 2P SAO, forming Al11Si2. The corresponding anion and cation clusters keep their geometry of the neutral intact, and the ionization energy is low compared to others, showing that Al11Si2 is characterized to be, Si@Al11Si as an alk.-like binary superatom. For Al21Si2, a face-sharing bi-icosahedral structure was identified to be the most stable as dimeric superatom clusters.
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159Akutsu, M.; Koyasu, K.; Atobe, J.; Hosoya, N.; Miyajima, K.; Mitsui, M.; Nakajima, A. Experimental and theoretical characterization of aluminum-based binary superatoms of Al12X and their cluster salts. J. Phys. Chem. A 2006, 110, 12073– 12076, DOI: 10.1021/jp065161pGoogle Scholar159https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVyrsb7O&md5=76e9faaeef775f9b41ddf1c0b5008304Experimental and Theoretical Characterization of Aluminum-Based Binary Superatoms of Al12X and Their Cluster SaltsAkutsu, Minoru; Koyasu, Kiichirou; Atobe, Junko; Hosoya, Natsuki; Miyajima, Ken; Mitsui, Masaaki; Nakajima, AtsushiJournal of Physical Chemistry A (2006), 110 (44), 12073-12076CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The geometric and electronic structures of aluminum binary clusters, AlnX (X = Si and P), have been investigated, using mass spectrometry, anion photoelectron spectroscopy, photoionization spectroscopy, and theor. calcns. Both exptl. and theor. results show that Al12Si has a high ionization energy and low electron affinity and Al12P has a low ionization energy, both with the icosahedral structure having a central Si or P atom, revealing that Al12Si and Al12P exhibit rare-gas-like and alkali superatoms, resp. Expts. confirmed the possibility that the change in the total no. of valence electrons on substitution could produce ionically bound binary superatom complexes, the binary cluster salts Al12P+F- and Al12B-Cs+.
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160Li, X.; Wang, L.-S. Experimental search and characterization of icosahedral clusters: Al12X– (X = C, Ge, Sn, Pb). Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 65, 153404, DOI: 10.1103/PhysRevB.65.153404Google Scholar160https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjtV2nsbg%253D&md5=3d4277a77db43d5febd6024a51e99901Experimental search and characterization of icosahedral clusters: Al12X- (X=C, Ge, Sn, Pb)Li, Xi; Wang, Lai-ShengPhysical Review B: Condensed Matter and Materials Physics (2002), 65 (15), 153404/1-153404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Photoelectron spectra of Al12X- (X=C, Ge, Sn, Pb) probe the electronic structure of Al12X. These clusters, all possessing 40 valence electrons, were expected to be magic nos. with Ih-X@Al12 structures, closed electron shells, and large energy gaps. For X = Ge, Sn, and Pb that was indeed the case, although non-Ih isomers were also obsd. The energy gaps of the 3 Ih-X@Al12 species range from 1.1 to 1.3 eV. The spectra of Al12C- were distinctly different from the other species, confirming that it does not possess an icosahedral structure.
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161Seitsonen, A. P.; Laasonen, K.; Nieminen, R. M.; Klein, M. L. Structure of CAl12. J. Chem. Phys. 1995, 103, 8075– 8080, DOI: 10.1063/1.470172Google Scholar161https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXptFWqurc%253D&md5=9ffcee77278f1ac7f21d7809de337c19Structure of CAl12Seitsonen, Ari P.; Laasonen, Kari; Nieminen, R. M.; Klein, Michael L.Journal of Chemical Physics (1995), 103 (18), 8075-80CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures of an isolated CAl12 cluster and a solid composed of CAl12 clusters have been studied using the Car-Parrinello method, based on the d. functional theory and the local d. approxn. We have compared the results of using the ultrasoft Vanderbilt pseudopotential with those of both a traditional pseudopotential and a LCAO method. We have confirmed the high stability of the cluster in its icosahedral structure. However, we show that the cluster-assembled solid is unstable against melting of the clusters, as previously found for SiAl12.
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162Li, S.; Gong, X. Neutral and negatively charged Al12X (X = Si, Ge, Sn, Pb) clusters studied from first principles. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 045432, DOI: 10.1103/PhysRevB.74.045432Google Scholar162https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XotFWntb4%253D&md5=b7729adf5cec953fa7700b19659b8345Neutral and negatively charged Al12X (X = Si, Ge, Sn, Pb) clusters studied from first principlesLi, S. F.; Gong, X. G.Physical Review B: Condensed Matter and Materials Physics (2006), 74 (4), 045432/1-045432/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The ground states properties of the title clusters were calcd. by DFT-GGA method. All clusters prefer icosahedral structure, in agreement with previous calcns. However, each of Al12X (X = Ge, Sn, Pb) neutral and ionic clusters shows C5v symmetry with atom X located on the cluster surface, contrary to the conclusion from the previous exptl. work [Phys. Rev. B 65, 153404 (2002)].
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163Kumar, V.; Sundararajan, V. Ab initio molecular-dynamics studies of doped magic clusters and their interaction with atoms. Phys. Rev. B: Condens. Matter Mater. Phys. 1998, 57, 4939– 4942, DOI: 10.1103/PhysRevB.57.4939Google Scholar163https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXhtFyju7s%253D&md5=7a2328cdd8241fc489196699cc2d9d1eAb initio molecular-dynamics studies of doped magic clusters and their interaction with atomsKumar, Vijay; Sundararajan, V.Physical Review B: Condensed Matter and Materials Physics (1998), 57 (8), 4939-4942CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We present results of the at. and electronic structures of icosahedral Al12X (X = Si, Ge, and Sn) clusters using the ab initio mol.-dynamics method within the local-d.-functional theory. Substitutional doping of a Al13 cluster by a tetravalent atom leads to a substantial gain in energy in all the cases studied. Tin is found to have a lower energy at a vertex site in contrast to the central site for Si and Ge, leading to surface segregation of Sn in these clusters. Also in the case of a Al13Si cluster, Si occupies the central site of a capped icosahedral structure. These results when interpreted in terms of the interaction of closed shell clusters with atoms leads to a relatively strong interaction of Al12Si with Al as compared to the weak interaction of rare gas atoms with other elements.
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164Kumar, V.; Bhattacharjee, S.; Kawazoe, Y. Silicon-doped icosahedral, cuboctahedral, and decahedral clusters of aluminum. Phys. Rev. B: Condens. Matter Mater. Phys. 2000, 61, 8541– 8547, DOI: 10.1103/PhysRevB.61.8541Google Scholar164https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhvVSnsrY%253D&md5=670c529946f603bb0207ac9ce5e4412aSilicon-doped icosahedral, cuboctahedral, and decahedral clusters of aluminumKumar, Vijay; Bhattacharjee, Satadeep; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2000), 61 (12), 8541-8547CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Most stable structures and phys. properties were studied for silicon-doped Al13, Al19, and Al23 clusters using the ab initio mol.-dynamics method within the framework of a plane-wave pseudopotential approach and the local d. as well as the generalized gradient approxns. The lowest energy structures of the undoped clusters were found to be Jahn-Teller distorted icosahedron, double icosahedron, and decahedron, resp. Substitutional doping with a Si impurity makes these clusters electronically closed shell and leads to a large gain in the binding energy, which decreases with an increase in the cluster size in a nonmonotonic way. The heat of soln. of a Si atom in clusters was found to be exothermic as compared to endothermic behavior in bulk aluminum. A Si impurity was found to stabilize the Al18Si cluster in cuboctahedral structure. However, a capped icosahedron as well as a double icosahedron were found to be nearly degenerate with about 1.77 eV higher binding energy. For Al22Si, the decahedral isomer has the lowest energy with a HOMO-LUMO gap of 0.82 eV. It is also found to be very stable when heated at 700 K. Similar results are likely to hold in the case of doping with germanium. We discuss the significance of these results for the understanding of the stability of silicon-doped quasicrystals.
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165Kumar, V.; Kawazoe, Y. Hund’s rule in metal clusters: Prediction of high magnetic moment state of Al12Cu from first-principles calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2001, 64, 115405, DOI: 10.1103/PhysRevB.64.115405Google Scholar165https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXmsFCjsbo%253D&md5=8b37b03ef7df2757af3e991b22b29349Hund's rule in metal clusters: Prediction of high magnetic moment state of Al12Cu from first-principles calculationsKumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2001), 64 (11), 115405/1-115405/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Using ab initio pseudopotential plane wave method and generalized gradient approxn. for the exchange and correlation energy, we report the finding of high spin ground state of Al12Cu cluster in accordance with the Hund's rule of max. spin at half-filling. It has perfect icosahedral symmetry and a magnetic moment of 3μB, forming an open shell superatom. Further studies of its interaction with an Al atom have led to an electronically closed shell magic cluster with 1.68 eV highest occupied-LUMO (HOMO-LUMO) gap such that the added Al atom is incorporated within the cage around the Cu atom.
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166Chen, G.; Kawazoe, Y. Structural and electronic properties of Al12X+ (X = C, Si, Ge, Sn, and Pb) clusters. J. Chem. Phys. 2007, 126, 014703, DOI: 10.1063/1.2429063Google Scholar166https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXosVCksg%253D%253D&md5=5693ce2c17aa4b279ae6f26503e32851Structural and electronic properties of Al12X+ (X = C, Si, Ge, Sn, and Pb) clustersChen, G.; Kawazoe, Y.Journal of Chemical Physics (2007), 126 (1), 014703/1-014703/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Using the DFT-GGA method (VASP code), the authors have studied the structural and electronic properties of Al12X+ (X = C, Si, Ge, Sn, and Pb) clusters. The ground state of Al12C+ is a low symmetry Cs structure instead of an icosahedron. However, for the Si, Ge, Sn, and Pb cases the icosahedral structure is favored. The ground states of Al12Si+ and Al12Ge+ have icosahedral structures, while the C5ν structures optimized from an icosahedron with a vertex capped by a tetravalent atom have the highest binding energy for Al12Sn+ and Al12Pb+ clusters. The Ih structure and the C5ν structure are almost degenerate for Al12Ge+ with binding energy difference of only 0.03 eV. The electronic properties are altered much by removing an electron from the neutral cluster. The binding strength of a valence electron is enhanced, while the binding energy of the cluster is reduced substantially. Due to the open electronic shell, the HOMO-LUMO gaps are ∼0.3 eV for these clusters.
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167Khanna, S.; Jena, P. Atomic clusters: Building blocks for a class of solids. Phys. Rev. B: Condens. Matter Mater. Phys. 1995, 51, 13705– 13716, DOI: 10.1103/PhysRevB.51.13705Google Scholar167https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXlvVGqtrg%253D&md5=40eea46e945f6802f25c4a3392bd447eAtomic clusters: building blocks for a class of solidsKhanna, S. N.; Jena, P.Physical Review B: Condensed Matter (1995), 51 (19), 13705-16CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)At. clusters with suitable size and compn. can be designed to mimic the chem. of atoms in the Periodic Table. These clusters which can be viewed as "super atoms" could then form the building blocks for a class of solids with unique structural, electronic, optical, magnetic, and thermodn. properties. Using d.-functional calcns., we outline the design principles for these clusters and describe the role of geometry and electronic shell structure on cluster-cluster interaction.
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168Kumar, V. Al10Li8: A magic compound cluster. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 60, 2916– 2920, DOI: 10.1103/PhysRevB.60.2916Google Scholar168https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksFyhsb4%253D&md5=cd5ba35c9864f83673f19452e3cb49e0Al10Li8: A magic compound clusterKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (1999), 60 (4), 2916-2920CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We report the finding of a layered Al10Li8 compd. cluster using the ab initio mol.-dynamics method. It has closed geometric as well as electronic shells and 1.62 eV highest occupied-LUMO (HOMO-LUMO) gap. With 38 valence electrons, it forms a class of magic clusters different from the known magic behavior of s-p-bonded metal clusters with 40 electrons. The bonding in this cluster is covalent between the aluminum atoms and ionic between the Al and Li shells. A similar result has been obtained for Al10Na8. However, the binding energy and HOMO-LUMO gap are smaller. A few other possibilities of larger layered clusters in this system are also discussed.
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169Thomas, O.; Zheng, W.-J.; Lippa, T.; Xu, S.-J.; Lyapustina, S.; Bowen, K., Jr In search of theoretically predicted magic clusters: Lithium-doped aluminum cluster anions. J. Chem. Phys. 2001, 114, 9895– 9900, DOI: 10.1063/1.1365110Google Scholar169https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjvFWhtLg%253D&md5=152ea05cbc590fb8ba16367c5da2136fIn search of theoretically predicted magic clusters: Lithium-doped aluminum cluster anionsThomas, O. C.; Zheng, W.-J.; Lippa, T. P.; Xu, S.-J.; Lyapustina, S. A.; Bowen, K. H., Jr.Journal of Chemical Physics (2001), 114 (22), 9895-9900CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Li-doped Al cluster anions, LiAln- were generated in a laser vaporization source and examd. via mass spectrometry and anion photoelectron spectroscopy (n = 3-15). The mass spectrum of the LiAln- series exhibits a local min. in intensity at n = 13. The electron affinity vs. cluster size trend also shows a dip at n = 13. Agreement is quite good between measured electron affinity values and those calcd. by Rao, Khanna, and Jena, suggesting that their predictions about the structure and bonding of LiAl13 and other clusters in this series are also largely valid.
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170Rao, B.; Jena, P. Energetics and electronic structure of carbon doped aluminum clusters. J. Chem. Phys. 2001, 115, 778– 783, DOI: 10.1063/1.1379973Google Scholar170https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXkslygtL4%253D&md5=493bff60e42563c47fd0a603274f0a92Energetics and electronic structure of carbon doped aluminum clustersRao, B. K.; Jena, P.Journal of Chemical Physics (2001), 115 (2), 778-783CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The energetics and the electronic structure of AlnC clusters (n = 3, 4, 5; 11, 12, 13) have been studied by a global optimization of their geometry without any symmetry constraint. The total energies of these clusters both in neutral and charged states are calcd. using an all-electron basis and the generalized gradient approxn. to the d. functional theory. While Al4C and Al12C clusters share some characteristic features of closed shell structures, namely enhanced stability and low electron affinity compared to their neighboring sizes, their ionization potentials exhibit different behavior. These decrease steadily from Al3C to Al5C while that of Al12C is higher than its neighbors. Carbon is found to form planar structures in small AlnC clusters (n = 3, 4, 5) irresp. of their charge state, although neutral Al4C possesses a nearly degenerate tetrahedral isomer lying slightly higher in energy from the planar configuration. The results agree well with exptl. and previous theor. data. In larger AlnC (n = 11, 12, 13) clusters, carbon occupies an interior site. In Al12C, carbon occupies the center of an icosahedron while it is off-centered in Al11C and Al13C. As an electron is attached, the near degeneracies of the neutral Al4C is lifted, whereas nondegenerate isomers of neutral Al12C yield nearly degenerate anions. Both these features produce complicated photoelectron spectra making identification of their adiabatic electron affinity a difficult problem. With the exception of neutral Al12C, the bonding of carbon to aluminum atoms is governed primarily by covalent interaction. The above calcns. were also performed with a simplified basis by freezing the at. cores of aluminum. In most cases, this simple basis yields results in good agreement with all electron calcns.
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171Khanna, S.; Ashman, C.; Rao, B.; Jena, P. Geometry, electronic structure, and energetics of copper-doped aluminum clusters. J. Chem. Phys. 2001, 114, 9792– 9796, DOI: 10.1063/1.1367381Google Scholar171https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjvFWht70%253D&md5=ffbab28f4a4eabef26f9df662f0d2732Geometry, electronic structure, and energetics of copper-doped aluminum clustersKhanna, S. N.; Ashman, C.; Rao, B. K.; Jena, P.Journal of Chemical Physics (2001), 114 (22), 9792-9796CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Using d. functional theory and generalized gradient approxn. for exchange-correlation potential, we have calcd. the equil. geometries and energetics of neutral and neg. charged AlnCu (n=11,12,13,14) clusters. Unlike the alkali atom-doped aluminum clusters in the same size range, the copper atom resides inside the aluminum cluster cage. Furthermore, the 3d and 4s energy levels of Cu hybridize with the valence electrons of Al causing a redistribution of the MO energy levels of the Aln clusters. However, this redistribution does not affect the magic nos. of AlnCu clusters that could be derived by assuming that Cu donates one electron to the valence levels of Aln clusters. This behavior, brought about by the smaller size and large ionization potential of the copper atom, contributes to the anomalous properties of AlnCu- anions: Unlike AlnX- (X=alkali atom), the mass ion intensities of AlnCu- are similar to those of Aln-. The calcd. adiabatic electron affinities are also in very good agreement with expt.
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172Rao, B.; Khanna, S.; Jena, P. Isomers of Al13 clusters and their interaction with alkali atoms. Phys. Rev. B: Condens. Matter Mater. Phys. 2000, 62, 4666– 4671, DOI: 10.1103/PhysRevB.62.4666Google Scholar172https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXls1Wrt7Y%253D&md5=6c31b6e14421182212a5784ef9ce8a88Isomers of Al13 clusters and their interaction with alkali atomsRao, B. K.; Khanna, S. N.; Jena, P.Physical Review B: Condensed Matter and Materials Physics (2000), 62 (7), 4666-4671CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Global optimization of the geometry of Al13 cluster using the d.-functional theory and generalized gradient approxn. yields two nearly degenerate isomers having Jahn-Teller distorted icosahedral and decahedral structures. As these two isomers of Al13 interact with alkali-atoms X (X=Li, Na, K, Rb, and Cs), the Jahn-Teller distortions in the bare cluster isomers disappear in all cases except in Cs. The binding energy of alkali atoms, X to Al13 systematically decreases from Li to Cs for both the isomers. This is shown to result from a competition between the size and the ionization potential of the alkali atoms. In addn., the difference in the total energies between icosahedral and decahedral structures contg. the alkali atoms becomes smaller than that between the bare Al13 isomers. The vertical ionization potentials of Al3X is larger than that of Al13 in the decahedral structure while the opposite is the case with the icosahedral isomer. The above results based on a frozen core approxn. were repeated using an all-electron basis. While there are quant. differences between these results, these are negligible at the present level of theory.
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173Majumder, C.; Das, G.; Kulshrestha, S.; Shah, V.; Kanhere, D. Ground state geometries and energetics of ALnLi (n = 1, 13) clusters using ab initio density-based molecular dynamics. Chem. Phys. Lett. 1996, 261, 515– 520, DOI: 10.1016/0009-2614(96)01028-7Google Scholar173https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XmslCltLk%253D&md5=b5171b47d12f5d93007365ee8c627a06Ground state geometries and energetics of AlnLi (n = 1, 13) clusters using ab initio density-based molecular dynamicsMajumder, C.; Das, G. P.; Kulshrestha, S. K.; Shah, Vaishali; Kanhere, D. G.Chemical Physics Letters (1996), 261 (4,5), 515-520CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)Based on orbital-free, ab-initio, mol.-dynamics calcns., the geometries and energetics of lithium-doped aluminum clusters (ALnLi, n = 1, 13) have been investigated. It is seen that, a single impurity of Li affects the geometries of small (n < 6) clusters, and this effect is less pronounced for larger clusters. The results suggest extra stability for the Al3Li, Al6Li and Al13Li clusters, which are in contrast with our earlier results on LinAl. The results indicate that the Li atom segregates to the surface of the aluminum cluster and prefers to form a tetrahedron, wherever possible, with one of the triangular faces of Al atoms. In particular, for Al13Li, the Al13 core takes the most sym. icosahedral form with the Li atom occupying the outer 'hollow-site'.
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174Vichare, A.; Kanhere, D. Surface coverage studies of the icosahedron by Li using density based molecular dynamics. Eur. Phys. J. D 1998, 4, 89– 94, DOI: 10.1007/s100530050188Google Scholar174https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXnvFOlt7w%253D&md5=1834e202f0fe30a2906466f5bc069eb2Surface coverage studies of the Al13 icosahedron by Li using density based molecular dynamicsVichare, A. M.; Kanhere, D. G.European Physical Journal D: Atomic, Molecular and Optical Physics (1998), 4 (1), 89-94CODEN: EPJDF6; ISSN:1434-6060. (Springer-Verlag)D. based mol. dynamics has been used to investigate the ground state structures of heterogeneous binary clusters Al13Lin; n = 1, 2, 3, 4, 10, 19, 20, 21. Some of these structures have also been investigated by full Kohn-Sham based calcns. Our earlier investigations have shown that in the Al-Li cluster, the ground state configurations are the ones where the Al atoms form a core around which the Li atoms form a "cage". In the present work, we have chosen the well-known Al13 icosahedron as the surface over which we study the evolution of the surface coverage as the no. of Li atoms increases. On the basis of the earlier work, we expect that the Al13Li20 cluster would be the most stable and indeed our simulations do yield such a novel fivefold sym. stable structure formed out of purely metal atoms. This icosahedral substrate is also used to study the coverage of the aluminum surface by lithium atoms. For a small no. of Li atoms, these studies suggest that the Li-Li dimerization is not particularly favored.
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175Chandrachud, P.; Joshi, K.; Kanhere, D. Thermodynamics of carbon-doped Al and Ga clusters: Ab initio molecular dynamics simulations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 76, 235423, DOI: 10.1103/PhysRevB.76.235423Google Scholar175https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtVahtg%253D%253D&md5=0471c7b8a9cddc5cdd1f46f3eaf96a93Thermodynamics of carbon-doped Al and Ga clusters: Ab initio molecular dynamics simulationsChandrachud, Prachi; Joshi, Kavita; Kanhere, D. G.Physical Review B: Condensed Matter and Materials Physics (2007), 76 (23), 235423/1-235423/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We have carried out extensive first principles thermodn. simulations for Al13, Ga13, Al12C, and Ga12C. The results are based on the simulation time of 2.4 ns for each of the clusters, and the heat capacity curves have been calcd. using multiple-histogram technique. Both clusters Al13 and Ga13 show higher than bulk melting temps. Upon doping, there is a substantial redn. in the melting temps. of the host clusters. In the case of Ga, the carbon atom changes the geometry from decahedral to icosahedral. This change in the geometry changes the heat capacity curve significantly, making the solidlike to liquidlike transition sharper. Our results bring out the fact that an impurity can be used to tune the finite temp. properties of small clusters.
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176Charkin, O.; Charkin, D.; Klimenko, N.; Mebel, A. A theoretical study of isomerism in doped aluminum XAl12 clusters (X = B, Al, Ga, C, Si, Ge) with 40 valence electrons. Chem. Phys. Lett. 2002, 365, 494– 504, DOI: 10.1016/S0009-2614(02)01512-9Google Scholar176https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XosVeks7w%253D&md5=0f1c4baf86eec1198bbc9e1fa0ea80bdA theoretical study of isomerism in doped aluminum XAl12 clusters (X = B, Al, Ga, C, Si, Ge) with 40 valence electronsCharkin, O. P.; Charkin, D. O.; Klimenko, N. M.; Mebel, A. M.Chemical Physics Letters (2002), 365 (5,6), 494-504CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)D. functional B3LYP calcns. with the 6-31G* and 6-311+G* basis sets have been employed in order to investigate the structure, vibrational frequencies, relative energies, and vertical ionization potentials of low-lying isomers in the family of doped aluminum clusters XAl12- (X = B, Al, Ga) and XAl12 (X = C, Si, Ge). Isomerization barriers have been also detd. The results are compared with the data of previous similar calcns. for endohedral and exohedral isomers of the alane salts Ln+[Al12H12]2- to analyze similarity and differences between the aluminides and alanes.
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177Wu, C.; Lu, P.; Yu, Z.; Ding, L.; Liu, Y.; Han, L. Structural and electronic properties of neutral clusters Al12X (X = P, As, Sb, and Bi) and their cations. J. Comput. Theor. Nanosci. 2013, 10, 1055– 1060, DOI: 10.1166/jctn.2013.2806Google Scholar177https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpsFGrtL8%253D&md5=acf93e1b305c6e61076cb084daa1045aStructural and electronic properties of neutral clusters Al12X (X = P, As, Sb, and Bi) and their cationsWu, Chengjie; Lu, Pengfei; Yu, Zhongyuan; Ding, Lu; Liu, Yumin; Han, LihongJournal of Computational and Theoretical Nanoscience (2013), 10 (5), 1055-1060CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)The structural and electronic properties of neutral clusters Al12X (X = P, As, Sb, and Bi) and their cations have been investigated within the d. functional theory (DFT) using the generalized gradient approxn. (GGA) for the exchange correlation potential. It is obsd. that the ground states of both neutral and cationic Al12P cluster tend to icosahedral structure, while the equil. geometries of Al12X (X = As, Sb, and Bi), either neutral or cationic clusters, favor the C5v structures with doped atom X occupied a peripheral position. The bonding character has been analyzed by calcg. the Mulliken charges and Al-X distances. We found that charge transfers from Al to doped-X site. Clusters possess same symmetry display a similar trend of DOS. Besides, from the PDOS figures, the s, p, d states of doped X atoms play different roles in Al12X (X = P, As, Sb, and Bi) clusters for their most stable structures.
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178Xie, R.-H.; Bryant, G. W.; Zhao, J.; Kar, T.; Smith, V. H., Jr Tunable optical properties of icosahedral, dodecahedral, and tetrahedral clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 125422, DOI: 10.1103/PhysRevB.71.125422Google Scholar178https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXivFensbo%253D&md5=2da6c6586629f17a8520b948fa7baedeTunable optical properties of icosahedral, dodecahedral, and tetrahedral clustersXie, Rui-Hua; Bryant, Garnett W.; Zhao, Jijun; Kar, Tapas; Smith, Vedene H., Jr.Physical Review B: Condensed Matter and Materials Physics (2005), 71 (12), 125422/1-125422/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using time-dependent d.-functional theory, the authors show that the first singlet excitations of a series of icosahedral, dodecahedral, and tetrahedral clusters are optically forbidden and that their optical absorption gaps and spectral properties are size, shape, and compn. dependent and can be tuned broadly in the UV-visible region. Taking icosahedral clusters Al@Al12 and Al@Pb12 as examples, the authors demonstrate that the optical gaps of icosahedral clusters can be tailored from the UV to near IR by properly doping them with (transition) metals, hydrogen, group VIIB atoms, and org. functional groups. Their study suggests icosahedral, dodecahedral, and tetrahedral clusters are suitable for tunable optical applications.
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179Li, S.; Gong, X. Charge-induced structural changes in Al12C clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 075404, DOI: 10.1103/PhysRevB.70.075404Google Scholar179https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnt1yrsrY%253D&md5=7bd3ecd0ec9a8ea2a0a333181c6e9158Charge-induced structural changes in Al12C clustersLi, S. F.; Gong, X. G.Physical Review B: Condensed Matter and Materials Physics (2004), 70 (7), 075404/1-075404/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The structures of Al12C and Al12C- clusters are studied by using the d. functional theory. We find that the charging on the icosahedral Al12C cluster drives the carbon atom from the center of the cluster to its surface. The optimized ground state structure of Al12C- cluster has a low symmetry, in agreement with exptl. observation.
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180Sun, Q.; Wang, Q.; Yu, J.; Kumar, V.; Kawazoe, Y. Real-space representation of electron localization and shell structure in jelliumlike clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2001, 63, 193408, DOI: 10.1103/PhysRevB.63.193408Google Scholar180https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjt1yqu7s%253D&md5=3beb4bceeaff0ccce09a342a2507f5f7Real-space representation of electron localization and shell structure in jelliumlike clustersSun, Q.; Wang, Q.; Yu, J. Z.; Kumar, V.; Kawazoe, Y.Physical Review B: Condensed Matter and Materials Physics (2001), 63 (19), 193408/1-193408/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Results of first-principles calcns. on pure and doped aluminum clusters are analyzed using the electron localization function (ELF) to obtain a real-space representation of the electronic shell structure. Our results provide a quant. anal. of the bonding nature and localization of charge in jelliumlike metal clusters and show that similar to atoms, ELF reproduces the electronic shell structure of clusters in real space.
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181Wang, B.; Zhao, J.; Shi, D.; Chen, X.; Wang, G. Density-functional study of structural and electronic properties of AlnN (n = 2–12) clusters. Phys. Rev. A: At., Mol., Opt. Phys. 2005, 72, 023204, DOI: 10.1103/PhysRevA.72.023204Google Scholar181https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpvFGhurw%253D&md5=0cca4d9e2cba9e0b721dd26c531ce31eDensity-functional study of structural and electronic properties of AlnN (n=2-12) clustersWang, Baolin; Zhao, Jijun; Shi, Daning; Chen, Xiaoshuang; Wang, GuanghouPhysical Review A: Atomic, Molecular, and Optical Physics (2005), 72 (2, Pt. B), 023204/1-023204/5CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)The lowest energy structures and electronic properties of AlnN (n = 2-12) clusters were studied using d.-functional theory. The equil. geometries of AlnN clusters with up to n = 12 were detd. from a no. of possible structural isomers at each size. The Al7N cluster was found be particularly stable with higher binding energy and larger electronic gap. For all the AlnN clusters studied, we found charge transfers from the Al to N site and co-existence of ionic and covalent bonding characteristics.
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182Molina, B.; Soto, J. R.; Castro, J. J. Stability and nonadiabatic effects of the endohedral clusters X@Al12 (X = B, C, N, Al, Si, P) with 39, 40, and 41 valence electrons. J. Phys. Chem. C 2012, 116, 9290– 9299, DOI: 10.1021/jp3004135Google Scholar182https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xks1Citrk%253D&md5=86df4c4528f69c459f6bb2f172709b05Stability and Nonadiabatic Effects of the Endohedral Clusters X@Al12 (X = B, C, N, Al, Si, P) with 39, 40, and 41 Valence ElectronsMolina, Bertha; Soto, Jorge R.; Castro, Jorge J.Journal of Physical Chemistry C (2012), 116 (16), 9290-9299CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Metallic nanoclusters, with 1 electron or hole difference from closed shell, might end up in a degenerate state undergoing a Jahn-Teller distortion as a result of nonadiabatic effects, which are a manifestation of the electron-vibron coupling. Here, the authors report a theor. study on the stability and nonadiabaticity of the neutral and charged endohedral clusters X@Al12 (X = B, C, N, Al, Si, P) around icosahedral symmetry, for 39, 40, and 41 valence electrons. The nonadiabatic effects are evaluated through the Jahn-Teller gain for the distorted cluster and their effect on the calcd. electronic d. of states is analyzed. For the 40 electron valence systems, the authors present the full vibrational spectra. Results are discussed within the framework of the superatom model, and show that not all systems are well described by the spherical jellium model and that nonadiabaticity is better represented by ellipsoidal models. The authors present a detail discussion of the Al13-1 electron detachment process and show how, through a comparison with available exptl. photoelectron spectroscopy data, the nonadiabaticity can be estd.
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183Jimenez-Izal, E.; Moreno, D.; Mercero, J. M.; Matxain, J. M.; Audiffred, M.; Merino, G.; Ugalde, J. M. Doped aluminum cluster anions: size matters. J. Phys. Chem. A 2014, 118, 4309– 4314, DOI: 10.1021/jp501496bGoogle Scholar183https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXotFCqs7o%253D&md5=cdbe74d3e74fdc64269d492da5e5fc4aDoped Aluminum Cluster Anions: Size MattersJimenez-Izal, Elisa; Moreno, Diego; Mercero, Jose M.; Matxain, Jon M.; Audiffred, Martha; Merino, Gabriel; Ugalde, Jesus M.Journal of Physical Chemistry A (2014), 118 (24), 4309-4314CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The global min. of the cluster anions with the generic chem. formula (XAl12)2-, where X = Be, Mg, Ca, Sr, Ba, and Zn, are detd. by an extensive search of their potential energy surfaces using the Gradient Embedded Genetic Algorithm (GEGA). All the characterized global min. have an icosahedral-like structure, resembling that of the Al13- cluster. These cages comprise closed-shell electronic configurations with 40 electrons, therefore, in accordance to the jellium model, they are predicted to be highly stable and amenable to exptl. detection. The two preferred sites for the dopant species, at the center and at surface of the icosahedral cage, are stabilized depending on the at. radius of X. Thus, while the small dopants (X = Be, Zn) sit preferably at the center of the cage, the preferred site for X = Mg, Ca, Sr, and Ba is at the surface. Since these dianions are not stable towards electron detachment, one Li cation is added in order to yield stable systems. Our computations show that in the global min. form of Li(XAl12)-, the lithium cation, ionically bonded to the Al atoms, does not change the structure of the (XAl12)2- core.
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184Lu, Q.; Jalbout, A.; Luo, Q.; Wan, J.; Wang, G. Theoretical study of hydrogenated Mg, Ca@Al12 clusters. J. Chem. Phys. 2008, 128, 224707, DOI: 10.1063/1.2937144Google Scholar184https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXntFyntLg%253D&md5=bcba057a88dfbfd7c9645adf4e107284Theoretical study of hydrogenated Mg, Ca@Al12 clustersLu, Q. L.; Jalbout, A. F.; Luo, Q. Q.; Wan, J. G.; Wang, G. H.Journal of Chemical Physics (2008), 128 (22), 224707/1-224707/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The studies on the structure and electronic properties of hydrogenated metal embedded Al12 cage clusters have been performed by d. functional theory calcns. We have investigated aluminum cluster hydrides with 12 and 14 hydrogen atoms, resp. Insertion of the Mg, Ca alkali metals remarkably enhances the stability of the aluminum clusters. The hydrogen atom prefers to occupy on-top sites along the surface of the clusters. Mulliken population anal. indicates that significant charge transfer occurs between the Mg and Ca atoms and the Al atoms. Our computations suggest that these clusters appear to be phys. and chem. stable. (c) 2008 American Institute of Physics.
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185Charkin, O.; Klimenko, N.; Charkin, D.; Mebel, A. Isomerism of Doped Aluminum Clusters with the Icosahedral [Al12] Cage. Russ. J. Inorg. Chem. 2005, 50, S17Google ScholarThere is no corresponding record for this reference.
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186Charkin, O. P.; Charkin, D. O.; Klimenko, N. M.; Mebel, A. M. A theoretical study of isomerism in doped aluminum MAl12 and MAl12X12 clusters with 40 and 50 valence electrons. Faraday Discuss. 2003, 124, 215– 237, DOI: 10.1039/b211114dGoogle Scholar186https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmtFertrY%253D&md5=a2618732b80e930b80ac7fa106b65834A theoretical study of isomerism in doped aluminum MAl12 and MAl12X12 clusters with 40 and 50 valence electronsCharkin, Oleg P.; Charkin, Dmitry O.; Klimenko, Nina M.; Mebel, Alexander M.Faraday Discussions (2003), 124 (), 215-237CODEN: FDISE6; ISSN:1359-6640. (Royal Society of Chemistry)Systematic d. functional B3LYP calcns. with the 6-31G* and 6-311+G* basis sets have been employed in order to investigate the structure, vibrational frequencies, relative energies, vertical ionization potentials, and magnetic shielding consts. of endohedral and exohedral isomers in two related families of doped aluminum MAl12 and alane MAl12H12 clusters with 40 and 50 valence electrons, resp. Isomerization barriers have been also detd. Trends in these properties with changing heteroatom M in various series have been followed. The similarities and differences between the aluminides and alanes as well as between the alanes MAl12H12 and related boranes MB12H12 and gallanes MGa12H12 have been scrutinized.
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187Lei, X.-L. Geometrical and electronic properties of neutral and anionic AlnBm (n + m = 13) clusters. J. Cluster Sci. 2011, 22, 159– 172, DOI: 10.1007/s10876-011-0370-xGoogle Scholar187https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXms12ntLY%253D&md5=558c77846f8a57e8c987e58fb9dda850Geometrical and Electronic Properties of Neutral and Anionic Al n B m (n + m = 13) ClustersLei, Xue-LingJournal of Cluster Science (2011), 22 (2), 159-172CODEN: JCSCEB; ISSN:1040-7278. (Springer)Successively substituted Al13 cluster by B atom both neutral and anionic AlnBm (n + m = 13) clusters have been investigated by the d. functional theory (DFT) at B3LYP/6-31G (d) level, the aim is to understand the evolution of the structural and electronic properties as a function of compn. The results clearly show Al13 cluster as well as Al rich AlnBm clusters prefer the icosahedral geometries while increasing boron contents promote quasi-planar configurations. The geometrical structures of the optimized anionic AlnBm- clusters are very close to those of the neutral clusters with smaller structural modifications. Overall, the vertical ionization potential (VIP), the adiabatic electron affinity (AEA), and the energy gaps (Eg) of AlnBm clusters decrease with increasing of substitution. The largest values of second-order energy differences (Δ2E), VIP, and Eg of Al12B cluster indicate it possesses the most stability among all the investigated clusters, which accords to the exptl. results. The simulated photoelectron spectroscopies (PES) of AlnBm- clusters have also been discussed in this article.
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188Sun, W.-M.; Wu, D.; Li, X.-H.; Li, Y.; Chen, J.-H.; Li, C.-Y.; Liu, J.-Y.; Li, Z.-R. Quasi-Chalcogen characteristics of Al12Be: A new member of the three-dimensional periodic table. J. Phys. Chem. C 2016, 120, 2464– 2471, DOI: 10.1021/acs.jpcc.5b11917Google Scholar188https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltlKnug%253D%253D&md5=3bb0bf3deaa8e3733503c21a949f2d3bQuasi-Chalcogen Characteristics of Al12Be: A New Member of the Three-Dimensional Periodic TableSun, Wei-Ming; Wu, Di; Li, Xiang-Hui; Li, Ying; Chen, Jing-Hua; Li, Chun-Yan; Liu, Jia-Yuan; Li, Zhi-RuJournal of Physical Chemistry C (2016), 120 (4), 2464-2471CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The creative concept of superatom brings a new dimension to the conventional periodic table, which has been gradually enriched by both theor. and exptl. research. In this article, we propose a new member, namely, Al12Be, to the superatom family. The amazing similarity between the Al12Be cluster and the chalcogen elements makes the former an excellent superatom counterpart of the latter. In addn., Al12Be exhibits more exothermic first electron affinity (EA) and less endothermic second EA values due to its size advantage over the chalcogen atoms, showing the superatom superiority in this respect. The stable compds. formed between Al12Be and other atoms, such as carbon, beryllium, calcium, and lithium, provide further evidence to support the quasi-chalcogen identity of Al12Be.
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189Ouyang, Y.; Wang, P.; Xiang, P.; Chen, H.; Du, Y. Density-functional theory study of Aln and Aln–1Mg (n = 2–17) clusters. Comput. Theor. Chem. 2012, 984, 68– 75, DOI: 10.1016/j.comptc.2012.01.012Google Scholar189https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjt1Gnsr8%253D&md5=090eae9a2e1d26201bb58387c42f8f19Density-functional theory study of Aln and Aln -1Mg (n = 2-17) clustersOuyang, Yifang; Wang, Peng; Xiang, Peng; Chen, Hongmei; Du, YongComputational & Theoretical Chemistry (2012), 984 (), 68-75CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The equil. geometries, relative stabilities, both vertical and adiabatic of ionization potentials and electron affinities as well electronic properties of Aln and Aln -1Mg (n = 2-17) clusters have been systematically investigated by using B3LYP/6-311G(d). In general, the ground state structures of Aln -1Mg clusters have similar geometries as the host Aln clusters, except for Al4Mg. Starting from n = 7, the Mg atom prefers to stay away from the center of Aln clusters and locate on the site of the corresponding Aln clusters surface. The dissocn. energy of the Aln -1Mg clusters dissoc. into Aln -1 clusters with one Mg atom are lower than those dissoc. into Aln -2Mg clusters with one Al atom, which suggests that the Aln -1Mg clusters are likely to break into Aln -1 clusters with one Mg atom. The results of AEA and VEA, AIP and VIP and second-order difference energy indicate that the Aln -1Mg (n = 3, 5, 7, 9, 11, 13, 15, and 17) clusters are more stable than others, which reveals that the chem. activity of Aln -1Mg clusters are diminished. The electronic structure has been discussed and the results of natural charge population anal. shows that there is a charge transfer from 3s states of Mg atom to 3p states of Al atoms resulting in the strong s-p hybridization.
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190Zhang, J.; Sun, J.; Liu, Y.; Li, J.; Liang, X.; Duan, H. The first-principles study of Al12X (X = Sc-Zn) clusters and their adsorption of H, O and N. AIP Adv. 2016, 6, 075312, DOI: 10.1063/1.4959578Google Scholar190https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1Wmtr7O&md5=da67d4edf9c7c126e6b865bfdfd9f291The first-principles study of Al12X (X = Sc-Zn) clusters and their adsorption of H, O and NZhang, Jingjing; Sun, Jun; Liu, Yanqi; Li, Jiao; Liang, Xiaogang; Duan, HaimingAIP Advances (2016), 6 (7), 075312/1-075312/13CODEN: AAIDBI; ISSN:2158-3226. (American Institute of Physics)Started from the four types 13-atom high-sym. (Ih, Oh, D5h, D3h) close-packed structures and by replacing a 3d transition metal atom in the nonequivalent position, the geometrical and electronic properties of the doped Al12X (X = Sc-Zn) clusters are systematically studied by using the d.-functional theory. Close-packed (icosahedral-like) structures are found to be favorable for the ground state geometries and the degenerate isomers of Al12X (X = Sc, Ti, V, Ni, Cu) clusters. The magnetic moments of the doped Al12X (X = Cr, Mn and Fe) are substantially increased as compared with that of the pure Al13, which are mainly derived from the strong spin splitting of the d electrons of the doped atoms. For the absorption of H, O and N on the close-packed Al12X clusters, it is found that H atom tend to occupy the top or bridge site instead of the hollow site, but the adsorption sites of O and N atom are more complex. O and N are always adsorbed around the doped atom of the doped cluster with the doped atom on the surface and the adsorption energies of O and N on the doped clusters are all enhanced as compared with that on pure Al13, but it is quite different for the adsorption of H, which implies that the influences of the d electrons of the doped atoms on O and N are stronger than that on H. All doped clusters exhibit the same selective sequence of adsorption: O > N > H. (c) 2016 American Institute of Physics.
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191Castro, J.; Soto, J.; Molina, B. Jahn-Teller analysis of the electronic properties of the endohedral clusters M@Al12 (M = B, Al, Ga) and their anions. AIP Conf. Proc. 2011, 1420, 145– 150, DOI: 10.1063/1.3678625Google Scholar191https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XitFGrsrk%253D&md5=ddad6b12f9baa19a763f48583662582aJahn-Teller analysis of the electronic properties of the endohedral clusters MAl12 (M = B, Al, Ga) and their anionsCastro, J. J.; Soto, J. R.; Molina, B.AIP Conference Proceedings (2011), 1420 (Advanced Summer School in Physics), 145-150CODEN: APCPCS; ISSN:0094-243X. (American Institute of Physics)It is well established that several doped aluminum clusters (MAl12), with 40 valence electrons and the dopant M at the center of the icosahedral Al12 cage, present a highly stable icosahedral structure with electronic closed-shell and HOMO-LUMO gap comparable to C60 and Au20. It has also been shown that the 39 valence electrons cluster Al13 could be regarded as a superhalogen superatom, with an electron affinity close to the chlorine atom. However, when an electron is detached from an electronic closed-shell icosahedral system, we end up with a degenerated HOMO state, showing a Jahn-Teller instability, undergoing therefore a structural distortion to remove the electron degeneracy by lowering the symmetry. In this work we perform a Jahn-Teller anal. of the electronic properties of the endohedral clusters MAl12 (M = B, Al, Ga) under the symmetry breaking process, lowering their Ih symmetry to D2h for B and D3d for Al and Ga. We show the necessity of taking into account this symmetry breaking in order to obtain a proper estn. of their electron affinity. This study is based on an all-electron fully relativistic DFT calcn. (c) 2011 American Institute of Physics.
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192Zhao, J.; Liu, B.; Zhai, H.; Zhou, R.; Ni, G.; Xu, Z. Mass spectrometric and first principles study of AlnC– clusters. Solid State Commun. 2002, 122, 543– 547, DOI: 10.1016/S0038-1098(02)00210-7Google Scholar192https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XlvFelsb8%253D&md5=1562fb22fb7b13f17d9672eb6c92b579Mass spectrometric and first principles study of AlnC- clustersZhao, Jijun; Liu, Bingchen; Zhai, Huajin; Zhou, Rufang; Ni, Guoquan; Xu, ZhizhanSolid State Communications (2002), 122 (10), 543-547CODEN: SSCOA4; ISSN:0038-1098. (Elsevier Science Ltd.)The authors study Al-C mixed clusters by using time-of-flight mass spectrum expts. and ab initio calcns. Mass abundance distributions were obtained for anionic Al and Al-C mixed clusters. Besides the known magic Al clusters such as the Al13- and Al23-, the Al7C- cluster is particularly stable among those AlnC- clusters. D. functional calcns. were performed to det. the ground state structures of AlnC- clusters. The authors' results show that the Al7C- is a magic cluster with extremely high stability, which might serve as a building block for cluster-assembled materials.
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193Kumar, V. Ab initio molecular dynamics studies of metal clusters. Bull. Mater. Sci. 1997, 20, 745– 754, DOI: 10.1007/BF02747415Google Scholar193https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXmvFynur4%253D&md5=756dd6dd41e3275b90eb60377498768dAb initio molecular dynamics studies of metal clustersKumar, VijayBulletin of Materials Science (1997), 20 (6), 745-754CODEN: BUMSDW; ISSN:0250-4707. (Indian Academy of Sciences)A review with 32 refs. We present results of our ab-initio mol.-dynamics simulations on the at. and electronic structures of clusters of divalent metals (e.g., aluminum and antimony) which exhibit a range of bonding characteristics (e.g. nonmetal-metal transition, metallic and covalent, resp.). Results of these studies have been used to develop icosahedral Al12X (X = C, Si, and Ge) superatoms with 40 valence electrons which correspond to a filled electronic shell. It is found that the doping leads to a large gain in the binding energy as compared to Al13, suggesting this to be a novel way of developing species for cluster assembled materials. Further studies of adsorption of Li, Si, and Cl atoms on Al7 and Al13 clusters show marked variation in the adsorption behavior of clusters as a function of size and the adsorbate. Silicon reconstructs both the clusters and induces covalency in Al-Al bonds. We discuss the adsorption behavior in terms of the superatom-atom interactions.
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194Kumar, V. Icosahedral symmetry in clusters. Prog. Cryst. Growth Charact. Mater. 1997, 34, 95– 131, DOI: 10.1016/S0960-8974(97)00007-7Google Scholar194https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXjs1GgsL0%253D&md5=b053d9a1161c0e086593b1d2ed507fd7Icosahedral symmetry in clustersKumar, VijayProgress in Crystal Growth and Characterization of Materials (1997), 34 (1-4), 95-131CODEN: PCGMED; ISSN:0960-8974. (Elsevier)A review with 114 refs. First principles calcns. and simulations based on interat. potentials together with exptl. studies of abundance spectrum suggest icosahedral structures to be common for some magic clusters of diverse systems such as rare gases, metals, covalently bonded systems, and water. Close-packing models obtained from pair potentials are shown to be good representations of the structure of rare gas clusters. However, the electronic structure is found to play the important role in the at. structure and related properties of other clusters. Results of recent studies of fullerenes, their derivs. as well as some large icosahedral metal clusters contg. several thousand atoms are also presented. Further results on doped icosahedral clusters are discussed which hold promise for the development of new materials and for understanding the occurrence of icosahedral order in several aluminum alloys.
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195Frisch, M. J.; Trucks, G.; Schlegel, H.; Scuseria, G.; Robb, M.; Cheeseman, J.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. Gaussian 09, Revision D. 01. Gaussian. Inc.: Wallingford, CT 2009, 2, 4Google ScholarThere is no corresponding record for this reference.
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196Li, X.; Wu, H.; Wang, X.-B.; Wang, L.-S. S-p hybridization and electron shell structures in aluminum clusters: A photoelectron spectroscopy study. Phys. Rev. Lett. 1998, 81, 1909– 1912, DOI: 10.1103/PhysRevLett.81.1909Google Scholar196https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXls1Wjs74%253D&md5=1814686081ac4111879b1e1bb7e7d039s-p Hybridization and electron shell structures in aluminum clusters: a photoelectron spectroscopy studyLi, Xi; Wu, Hongbin; Wang, Xue-Bin; Wang, Lai-ShengPhysical Review Letters (1998), 81 (9), 1909-1912CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Using photoelectron spectroscopy of size-selected Alx- (x = 1-162) clusters, we studied the electronic structure evolution of Alx and obsd. that the Al 3s- and 3p-derived bands evolve and broaden with cluster size and begin to overlap at Al9. Direct spectroscopic signatures were obtained for electron shell structures with spherical shell closings at Al11-, Al13-, Al19-, Al23-, Al35-, Al37-, Al46, Al52, Al55-, Al56, Al66, and Al73-. The electron shell effect diminishes above Al75 and new spectral features appearing in Alx- (x>100) suggest a possible geometrical packing effect in large clusters.
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197Tsunoyama, H.; Akutsu, M.; Koyasu, K.; Nakajima, A. The stability of binary Al12X nanoclusters (X = Sc and Ti): Superatom or Wade’s polyhedron. J. Phys.: Condens. Matter 2018, 30, 494004, DOI: 10.1088/1361-648X/aaebdeGoogle Scholar197https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXktFCku7s%253D&md5=90847ec291978f6eb92ed6e4ac1e8aceThe stability of binary Al12X nanoclusters (X = Sc and Ti): superatom or Wade's polyhedronTsunoyama, Hironori; Akutsu, Minoru; Koyasu, Kiichirou; Nakajima, AtsushiJournal of Physics: Condensed Matter (2018), 30 (49), 494004/1-494004/7CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Binary nanoclusters (NCs) exhibit strong potential as building blocks for tailor-made scientific materials based on the precise tuning of their electron countings and spin states along with the synergistic effects that originate from the constituent elements. Herein, we studied the electronic and geometric structures of transition metal (TM) doped aluminum (Al) Al12X NCs (X = Sc and Ti), which are binary systems that extend from representative superatom Al13- anions. On the basis of the photoelectron spectroscopy (PES) and d. functional theory (DFT) calcns., Al12X anion and neutral structures are characterized as vertex-replaced icosahedron. The highly stable exohedral Al12X icosahedron is described based on an electron counting rule derived from the coupling of Wade-Mingos' rule and the jellium model.
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198Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 59, 1758– 1775, DOI: 10.1103/PhysRevB.59.1758Google Scholar198https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXkt12nug%253D%253D&md5=78a73e92a93f995982fc481715729b14From ultrasoft pseudopotentials to the projector augmented-wave methodKresse, G.; Joubert, D.Physical Review B: Condensed Matter and Materials Physics (1999), 59 (3), 1758-1775CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived. The total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addn., crit. tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed-core all-electron methods. These tests include small mols. (H2, H2O, Li2, N2, F2, BF3, SiF4) and several bulk systems (diamond, Si, V, Li, Ca, CaF2, Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
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199Kresse, G.; Furthermuller, J. Effect of Er doping on the electronic structure optical properties of ZnO. Phys. Rev. B 1996, 54, 11169– 11186Google Scholar199https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xms1Whu7Y%253D&md5=9c8f6f298fe5ffe37c2589d3f970a697Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis setKresse, G.; Furthmueller, J.Physical Review B: Condensed Matter (1996), 54 (16), 11169-11186CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The authors present an efficient scheme for calcg. the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrixes will be discussed. This approach is stable, reliable, and minimizes the no. of order Natoms3 operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special "metric" and a special "preconditioning" optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calcns. It will be shown that the no. of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order Natoms2 scaling is found for systems contg. up to 1000 electrons. If we take into account that the no. of k points can be decreased linearly with the system size, the overall scaling can approach Natoms. They have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable.
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200Leskiw, B. D.; Castleman, A. W. The interplay between the electronic structure and reactivity of aluminum clusters: Model systems as building blocks for cluster assembled materials. Chem. Phys. Lett. 2000, 316, 31– 36, DOI: 10.1016/S0009-2614(99)01295-6Google Scholar200https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXltlOjug%253D%253D&md5=d34c409e1f62d6e6cef7bf1f65231963The interplay between the electronic structure and reactivity of aluminum clusters: model systems as building blocks for cluster assembled materialsLeskiw, B. D.; Castleman, A. W.Chemical Physics Letters (2000), 316 (1,2), 31-36CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Reactions of aluminum-carbon cluster anions with oxygen were investigated under well-defined thermal conditions in a fast flow reactor. The resistance of particular species to the etching of oxygen is obsd. and is explained through the predicted shell closings of the Jellium model. The presence of Al7C-, in particular, is compatible with this cluster being a composite Jellium system stabilized by ion-polarizability interactions. This would be the first species of which we are aware that exits as a magic cluster in this context.
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201Sun, Q.; Wang, Q.; Gong, X. G.; Kumar, V.; Kawazoe, Y. Structures and stability of Al7C and Al7N clusters. Eur. Phys. J. D 2002, 18, 77– 81, DOI: 10.1140/e10053-002-0009-4Google Scholar201https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XitFyqu7w%253D&md5=2b8c5a9e1ede71a4f27407ecb6f69ffbStructures and stability of Al7C and Al7N clustersSun, Q.; Wang, Q.; Gong, X. G.; Kumar, V.; Kawazoe, Y.European Physical Journal D: Atomic, Molecular and Optical Physics (2002), 18 (1), 77-81CODEN: EPJDF6; ISSN:1434-6060. (Springer-Verlag)We report results of the at. and electronic structures of Al7C cluster using ab initio DFT-MD methods with ultrasoft pseudopotentials and generalized gradient approxn. The lowest energy structure was found to be the one in which carbon atom occupies an interstitial position in Al7 cluster. The recent observation of magic behavior of Al7C- cluster is due to a large HOMO-LUMO gap which makes Al7C- chem. inert. These results led us to the finding of a new neutral magic cluster, Al7N, which has the same no. of valence electrons as in Al7C- and a large HOMO-LUMO gap of 1.99 eV. Calcns. were carried out on (Al7N)2 to study interactions between magic clusters.
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202Bai, Q.; Song, B.; Hou, J.; He, P. First principles study of structural and electronic properties of AlnN (N = 1–19) clusters. Phys. Lett. A 2008, 372, 4545– 4552, DOI: 10.1016/j.physleta.2008.03.067Google Scholar202https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmsFelsro%253D&md5=5e87179040db258498c89db99b9248ecFirst principles study of structural and electronic properties of AlnN (n = 1-19) clustersBai, Qiugui; Song, Bin; Hou, Jinyu; He, PimoPhysics Letters A (2008), 372 (25), 4545-4552CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The structural and electronic properties of AlnN clusters were calcd. by the DFT-GGA method. The N atom tends to occupy an inside position for n ≤ 10 , but prefers a peripheral position with a bulk-like coordination for n > 10. As cluster size increases, an icosahedral-like motif emerges; the cluster grows by capping N and extra Al atoms on the Al13 icosahedron. Al3N and Al7N exhibit particularly high stability. The Al-N bonds may simultaneously possess ionic and covalent characteristics. The calcd. HOMO-LUMO gaps exhibit odd-even oscillations as n increases. The vertical ionization potential of the clusters tends to decrease with n increasing, while the vertical electron affinity shows the opposite trend.
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203Averkiev, B. B.; Call, S.; Boldyrev, A. I.; Wang, L.-M.; Huang, W.; Wang, L.-S. Photoelectron spectroscopy and Ab initio study of the structure and bonding of Al7N- and Al7N. J. Phys. Chem. A 2008, 112, 1873– 1879, DOI: 10.1021/jp7106236Google Scholar203https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtFylsbw%253D&md5=3ef95b0a8f78164082c6216075d4f657Photoelectron Spectroscopy and Ab Initio Study of the Structure and Bonding of Al7N- and Al7NAverkiev, Boris B.; Call, Seth; Boldyrev, Alexander I.; Wang, Lei-Ming; Huang, Wei; Wang, Lai-ShengJournal of Physical Chemistry A (2008), 112 (9), 1873-1879CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The electronic and geometrical structures of Al7N- are studied using photoelectron spectroscopy and ab initio calcns. Photoelectron spectra of Al7N- were obtained at 3 photon energies with 6 resolved spectral features at 193 nm. The spectral features of Al7N- are relatively broad, in particular for the ground state transition, indicating a large geometrical change from the ground state of Al7N- to that of Al7N. The ground state vertical detachment energy is 2.71 eV, whereas only an upper limit of ∼1.9 eV can be estd. for the ground state adiabatic detachment energy due to the broad detachment band. Global min. searches for A7N- and Al7N are performed using several theor. methods. Vertical electron detachment energies are calcd. using 3 different methods for the lowest energy structure and compared with the exptl. data. Calcd. results are in excellent agreement with the exptl. data. The global min. structure of Al7N- possesses C3v symmetry, which can be viewed as an Al atom capping a face of a N-centered Al6N octahedron. In the ground state of Al7N, the capping Al atom is pushed inward with the 3 adjacent Al-Al distances being stretched outward. Even though Al7N still possesses C3v symmetry, it is better viewed as a N-coordinated by 7 Al atoms in a cage-like structure. The chem. bonding in Al7N- is discussed from MO and natural bond anal.
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204Kumar, V. Chemical compositions at alloy surfaces. Phys. Rev. B: Condens. Matter Mater. Phys. 1981, 23, 3756– 3764, DOI: 10.1103/PhysRevB.23.3756Google Scholar204https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXhvVWhtL4%253D&md5=656d077cea1c42299b63c5a82b74fac1Chemical compositions at alloy surfacesKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (1981), 23 (8), 3756-64CODEN: PRBMDO; ISSN:0163-1829.A quasichem. formulation for chem. compn. at the surfaces of nonregular solid solns. is presented and applied to Ag-Au and Cu-Ni alloys. The results are compared with the existing exptl. values. It is obsd. that the use of the surface-energy data instead of the heat of vaporization gives good agreement with the expts. Surface relaxation effects are taken into account. The free energy of segregation is calcd. for several layers. The surface short-range order parameters are found to be quite different from the bulk values.
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205Kumar, V. Segregation at alloy surfaces. Surf. Sci. 1979, 84, L231– L234, DOI: 10.1016/0039-6028(79)90294-2Google Scholar205https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE1MXks1eisbY%253D&md5=698ef56ec5059bd56a710db735a5a712Segregation at alloy surfacesKumar, VijaySurface Science (1979), 84 (1), L231-L234CODEN: SUSCAS; ISSN:0039-6028.A theory is presented for segregation at alloy surfaces, where both the bond breaking and strain theories have been combined into one. The formulation can be applied to alloys of any concn. In addn., some ideas are described which should be considered while dealing with polycryst. samples. Good agreement is obtained with AES data on a Ni-Au system.
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206Guerra, C. F.; Snijders, J.; te Velde, G. t.; Baerends, E. Towards an order-N DFT method. Theor. Chem. Acc. 1998, 99, 391– 403, DOI: 10.1007/s002140050353Google Scholar206https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntl2lsL4%253D&md5=fbb6cec807384e9556f98d0485975efcTowards an order-N DFT methodGuerra, C. Fonseca; Snijders, J. G.; Te Velde, G.; Baerends, E. J.Theoretical Chemistry Accounts (1998), 99 (6), 391-403CODEN: TCACFW; ISSN:1432-881X. (Springer-Verlag)One of the most important steps in a Kohn-Sham (KS) type d. functional theory calcn. is the construction of the matrix of the KS operator (the Fock matrix). It is desirable to develop an algorithm for this step that scales linearly with system size. We discuss attempts to achieve linear scaling for the calcn. of the matrix elements of the exchange-correlation and Coulomb potentials within a particular implementation (the Amsterdam d. functional, ADF, code) of the KS method. In the ADF scheme the matrix elements are completely detd. by 3D numerical integration, the value of the potentials in each grid point being detd. with the help of an auxiliary function representation of the electronic d. Nearly linear scaling for building the total Fock matrix is demonstrated for systems of intermediate size (in the order of 1000 atoms). For larger systems further development is desirable for the treatment of the Coulomb potential.
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207Te Velde, G. t.; Bickelhaupt, F. M.; Baerends, E. J.; Fonseca Guerra, C.; van Gisbergen, S. J.; Snijders, J. G.; Ziegler, T. Chemistry with ADF. J. Comput. Chem. 2001, 22, 931– 967, DOI: 10.1002/jcc.1056Google Scholar207https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjtlGntrw%253D&md5=314e7e942de9b28e664afc5adb2f574fChemistry with ADFTe Velde, G.; Bickelhaupt, F. M.; Baerends, E. J.; Fonseca Guerra, C.; Van Gisbergen, S. J. A.; Snijders, J. G.; Ziegler, T.Journal of Computational Chemistry (2001), 22 (9), 931-967CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)A review with 241 refs. We present the theor. and tech. foundations of the Amsterdam D. Functional (ADF) program with a survey of the characteristics of the code (numerical integration, d. fitting for the Coulomb potential, and STO basis functions). Recent developments enhance the efficiency of ADF (e.g., parallelization, near order-N scaling, QM/MM) and its functionality (e.g., NMR chem. shifts, COSMO solvent effects, ZORA relativistic method, excitation energies, frequency-dependent (hyper)polarizabilities, at. VDD charges). In the Applications section we discuss the phys. model of the electronic structure and the chem. bond, i.e., the Kohn-Sham MO (MO) theory, and illustrate the power of the Kohn-Sham MO model in conjunction with the ADF-typical fragment approach to quant. understand and predict chem. phenomena. We review the "Activation-strain TS interaction" (ATS) model of chem. reactivity as a conceptual framework for understanding how activation barriers of various types of (competing) reaction mechanisms arise and how they may be controlled, for example, in org. chem. or homogeneous catalysis. Finally, we include a brief discussion of exemplary applications in the field of biochem. (structure and bonding of DNA) and of time-dependent d. functional theory (TDDFT) to indicate how this development further reinforces the ADF tools for the anal. of chem. phenomena.
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208Sharma, H.; Garg, I.; Dharamvir, K.; Jindal, V. Ab Initio Study of Structural and Electronic Properties of AlnN (n = 1–22) Clusters. J. Comput. Theor. Nanosci. 2010, 7, 2297– 2307, DOI: 10.1166/jctn.2010.1611Google Scholar208https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtF2murzI&md5=6d4ac2262d3a35e37e3040a39cffb277Ab initio study of structural and electronic properties of AlnN (n = 1-22) clustersSharma, Hitesh; Garg, Isha; Dharamvir, Keya; Jindal, V. K.Journal of Computational and Theoretical Nanoscience (2010), 7 (11), 2297-2307CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)We have investigated the structural and electronic properties of AlnN clusters for n = 1-22 using ab initio calcns. based on d. functional theory. Nitrogen prefers to stay at inside position for n < 10 and at the surface for n > 10. The binding energy of Aln increases with N addn. However, the binding energy of AlnN cluster shows a steep increase from n = 1-3 and thereafter a gradual decline up to n = 12. For n > 12, the binding energy is found to be nearly const. With N doping, ionization potential (IP) and electron affinity (EA) shows a significant change in pattern w.r.t Aln clusters for n ≤ 10. For n > 10 the pattern is oscillatory which is similar to pure Aln. The electronic properties of Aln are altered to a great extent with HOMO-LUMO gap increasing from 0.1 eV-1.6 eV in Aln to 0.5 eV-3.0 eV in AlnN resp. The HOMO-LUMO gap variation over a wide range could be exploited for tuning optical gap in visible range. The spin multiplicities and the Mulliken charges of AlnN clusters indicate significant charge redistribution in the vicinity of N atom which may lead to change in the chem. reactivity at sites suitable for catalytic activities. The calcd. results are in agreement with existing exptl. and theor. results.
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209Parr, R. G.; Zhou, Z. Absolute hardness: Unifying concept for identifying shells and subshells in nuclei, atoms, molecules, and metallic clusters. Acc. Chem. Res. 1993, 26, 256– 258, DOI: 10.1021/ar00029a005Google Scholar209https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXit1SisLY%253D&md5=790e6db4b9a2907db669f6b6ca350ccbAbsolute hardness: unifying concept for identifying shells and subshells in nuclei, atoms, molecules, and metallic clustersParr, Robert G.; Zhou, ZhongxiangAccounts of Chemical Research (1993), 26 (5), 256-8CODEN: ACHRE4; ISSN:0001-4842.The abs. hardness η, defined as one-half of the second deriv. of the energy with respect to the no. of particles, is related to the shell structure of nuclei, clusters and atoms (η vs. the at. no. Z), to the HOMO-LUMO gap, the difference between the ionization potential and the electron affinity, and to the total d. of states et the Fermi energy in metals.
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210Reveles, J. U.; Khanna, S.; Roach, P.; Castleman, A. Multiple valence superatoms. Proc. Natl. Acad. Sci. U. S. A. 2006, 103, 18405– 18410, DOI: 10.1073/pnas.0608781103Google Scholar210https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xhtlalu7zE&md5=3f9abb91e96626bc2633ebbd1635e091Multiple valence superatomsReveles, J. U.; Khanna, S. N.; Roach, P. J.; Castleman, A. W., Jr.Proceedings of the National Academy of Sciences of the United States of America (2006), 103 (49), 18405-18410CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)We recently demonstrated that, in gas phase clusters contg. aluminum and iodine atoms, an Al13 cluster behaves like a halogen atom, whereas an Al14 cluster exhibits properties analogous to an alk. earth atom. These observations, together with our findings that Al-13 is inert like a rare gas atom, have reinforced the idea that chosen clusters can exhibit chem. behaviors reminiscent of atoms in the periodic table, offering the exciting prospect of a new dimension of the periodic table formed by cluster elements, called superatoms. As the behavior of clusters can be controlled by size and compn., the superatoms offer the potential to create unique compds. with tailored properties. In this article, we provide evidence of an addnl. class of superatoms, namely Al-7, that exhibit multiple valences, like some of the elements in the periodic table, and hence have the potential to form stable compds. when combined with other atoms. These findings support the contention that there should be no limitation in finding clusters, which mimic virtually all members of the periodic table.
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211Chauhan, V.; Singh, A.; Majumder, C.; Sen, P. Structural, electronic and magnetic properties of binary transition metal aluminum clusters: Absence of electronic shell structure. J. Phys.: Condens. Matter 2014, 26, 015006, DOI: 10.1088/0953-8984/26/1/015006Google Scholar211https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFejurg%253D&md5=1ea8a7e000929c46fb5da4a4dd5bf377Structural, electronic and magnetic properties of binary transition metal aluminum clusters: absence of electronic shell structureChauhan, Vikas; Singh, Akansha; Majumder, Chiranjib; Sen, PrasenjitJournal of Physics: Condensed Matter (2014), 26 (1), 015006/1-015006/8, 8 pp.CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Single Cr, Mn, Fe, Co and Ni doped Al clusters having up to 12 Al atoms are studied using d. functional methods. The global min. of structure for all the clusters are identified, and their relative stability and electronic and magnetic properties are studied. FeAl4 and CoAl3 are found to have enhanced stability and arom. behavior. In contrast to binary transition metal alkali and transition metal alk. earth clusters, spherical shell models cannot describe the electronic structure of transition metal Al clusters.
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212Tam, N. M.; Van Duong, L.; Cuong, N. T.; Nguyen, M. T. Structure, stability, absorption spectra and aromaticity of the singly and doubly silicon doped aluminum clusters AlnSim0/+ with n = 3–16 and m = 1, 2. RSC Adv. 2019, 9, 27208– 27223, DOI: 10.1039/C9RA04004HGoogle Scholar212https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1ylsLvK&md5=7da3198ca5a4666dc0b895fed03a545cStructure, stability, absorption spectra and aromaticity of the singly and doubly silicon doped aluminum clusters AlnSim0/+ with n = 3-16 and m = 1, 2Tam, Nguyen Minh; Duong, Long Van; Cuong, Ngo Tuan; Nguyen, Minh ThoRSC Advances (2019), 9 (47), 27208-27223CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Structures of the binary AlnSim clusters in both neutral and cationic states were investigated using DFT and TD-DFT (B3LYP/6-311+G(d)) and (U)CCSD(T)/cc-pvTZ calcns. Silicon-doped aluminum clusters are characterized by low spin ground states. For small sizes, the Si dopant prefers to be located at vertices having many edges. For larger sizes, the Si atom prefers to be endohedrally doped inside an Aln cage. Relative stability, adiabatic ionization energy and dissocn. energies of each cluster size were evaluated. A characteristic of most Si doped Al clusters is the energetic degeneracy of two lowest-lying isomers. Calcd. results confirm the high stability of the sizes Al4Si2, Al12Si and Al11Si2+ as "magic" clusters, that exhibit 20 or 40 shell electrons and are thermodynamically more stable as compared to their neighbors. Electronic absorption spectra of isoelectronic magic clusters Al13-, Al12Si, and Al11Si2+ that have two pronounced bands corresponding to blue and violet lights, have been rationalized by using the electron shell model. The magnetically included ring c.d. (MICD) analyses suggest that they are also arom. structures as a result of the "magic" 40 shell electrons.
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213Lu, Q.; Wan, J. Sc-coated Si@Al12 as high-capacity hydrogen storage medium. J. Chem. Phys. 2010, 132, 224308, DOI: 10.1063/1.3439689Google Scholar213https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXntlGnu78%253D&md5=902f54feda4a29e764ab86cf724edc56Sc-coated Si@Al12 as high-capacity hydrogen storage mediumLu, Q. L.; Wan, J. G.Journal of Chemical Physics (2010), 132 (22), 224308/1-224308/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)H mols. adsorption and storage in Sc coated Si@Al12 cluster were studied using d. functional theory methods. Sc atoms can bind strongly to the surfaces of Si@Al12 due to the charge transfer between Sc and Si@Al12, and do not suffer from clustering on the substrate. Si@Al12 cluster coated with 3 and 4 Sc atoms can adsorb 16 and 18 H2 mols. with a binding energy of 0.28-0.63 eV/H2, corresponding to H storage capacity of 6.0 and 6.3%, resp. The stable Si@Al12 can be applied as one of candidates for H storage materials at ambient conditions. (c) 2010 American Institute of Physics.
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214Lochan, R. C.; Head-Gordon, M. Computational studies of molecular hydrogen binding affinities: The role of dispersion forces, electrostatics, and orbital interactions. Phys. Chem. Chem. Phys. 2006, 8, 1357– 1370, DOI: 10.1039/b515409jGoogle Scholar214https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XitlKmurw%253D&md5=b872b2e4491c7ea0ebdde9b587195d02Computational studies of molecular hydrogen binding affinities: The role of dispersion forces, electrostatics, and orbital interactionsLochan, Rohini C.; Head-Gordon, MartinPhysical Chemistry Chemical Physics (2006), 8 (12), 1357-1370CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Intermol. interactions between H2 and ligands, metals, and metal-ligand complexes det. the binding affinities of potential H storage materials (HSM), and thus their potential for practical use. A brief survey of current activity on HSM is given. The key issue of binding strengths is examd. from a basic perspective by surveying the distinct classes of interactions (dispersion, electrostatics, orbital interactions) in a general way and then in the context of calcd. binding affinities for a range of model systems.
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215Gong, X. G.; Kumar, V. Metallic coverings of calcium on C60. Chem. Phys. Lett. 2001, 334, 238– 244, DOI: 10.1016/S0009-2614(00)01386-5Google Scholar215https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXhtFejtr4%253D&md5=7e4591d3d77483a055c532db7b2c4a71Metallic coverings of calcium on C60Gong, X. G.; Kumar, V.Chemical Physics Letters (2001), 334 (4,5,6), 238-244CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)We present results of the electronic structure and stability of calcium coverings on C60 using a LCAO and the local d. functional approxn. Calcns. on CaxC60 with x = 12, 20 and 32 show partial charge transfer from calcium atoms to C60 and hybridization of the calcium and fullerene states. This leads to (i) a large binding energy of Ca on C60 which decreases with an increasing coverage and (ii) formation of a metallic shell on C60. The large abundance of the Ca32C60 complex is shown to be due to geometric factors in agreement with expts.
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216Yoon, M.; Yang, S.; Hicke, C.; Wang, E.; Geohegan, D.; Zhang, Z. Calcium as the superior coating metal in functionalization of carbon fullerenes for high-capacity hydrogen storage. Phys. Rev. Lett. 2008, 100, 206806, DOI: 10.1103/PhysRevLett.100.206806Google Scholar216https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtlSlsrc%253D&md5=3f9088c8fe7ce4f161e0acbb5c8563d3Calcium as the superior coating metal in functionalization of carbon fullerenes for high-capacity hydrogen storageYoon, Mina; Yang, Shenyuan; Hicke, Christian; Wang, Enge; Geohegan, David; Zhang, ZhenyuPhysical Review Letters (2008), 100 (20), 206806/1-206806/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We explore theor. the feasibility of functionalizing carbon nanostructures for hydrogen storage, focusing on the coating of C60 fullerenes with light alk.-earth metals. Our first-principles d. functional theory studies show that both Ca and Sr can bind strongly to the C60 surface, and highly prefer monolayer coating, thereby explaining existing exptl. observations. The strong binding is attributed to an intriguing charge transfer mechanism involving the empty d levels of the metal elements. The charge redistribution, in turn, gives rise to elec. fields surrounding the coated fullerenes, which can now function as ideal mol. hydrogen attractors. With a hydrogen uptake of >8.4 wt % on Ca32C60, Ca is superior to all the recently suggested metal coating elements.
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217Reyhani, A.; Mortazavi, S.; Mirershadi, S.; Moshfegh, A.; Parvin, P.; Golikand, A. N. Hydrogen storage in decorated multiwalled carbon nanotubes by Ca, Co, Fe, Ni, and Pd nanoparticles under ambient conditions. J. Phys. Chem. C 2011, 115, 6994– 7001, DOI: 10.1021/jp108797pGoogle Scholar217https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjsVClu70%253D&md5=ac67a3bc8348e4286c51a8ad2ab6f1a2Hydrogen Storage in Decorated Multiwalled Carbon Nanotubes by Ca, Co, Fe, Ni, and Pd Nanoparticles under Ambient ConditionsReyhani, A.; Mortazavi, S. Z.; Mirershadi, S.; Moshfegh, A. Z.; Parvin, P.; Golikand, A. NozadJournal of Physical Chemistry C (2011), 115 (14), 6994-7001CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We report a study on hydrogen storage in Ca, Co, Fe, Ni, and Pd decorated multiwalled carbon nanotubes (MWCNTs) by using two techniques: volumetric and electrochem. The results showed that hydrogen mols. are adsorbed on the defect sites and transported to the spaces between adjacent carbon via diffusion through both defect sites and opened tips into the layers. Hydrogen storage capacity can be improved in the decorated MWCNT by Co, Fe, Ni, and Ca metals in two approaches: (i) H2 adsorption via Kubas interaction and (ii) dissocn. of H2 mols. on the metal particles. The results reveal that Pd are more effective catalyst for hydrogen storage process. It was found that dissocn. of H2 occurs on the Pd particle, and hydrogen atoms are entered into the spaces between adjacent carbon layers. They create loosely bonds of CHx species and Pd-C-Hx complex which can be decompd. easily at lower temps. as compared to C-H chem. bonds.
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218Sun, Q.; Wang, Q.; Jena, P.; Kawazoe, Y. Clustering of Ti on a C60 surface and its effect on hydrogen storage. J. Am. Chem. Soc. 2005, 127, 14582– 14583, DOI: 10.1021/ja0550125Google Scholar218https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVGqs7fL&md5=1199dab8a8e9f7785b44a3b1acd73e3aClustering of Ti on a C60 Surface and Its Effect on Hydrogen StorageSun, Qiang; Wang, Qian; Jena, Puru; Kawazoe, YoshiyukiJournal of the American Chemical Society (2005), 127 (42), 14582-14583CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Pure carbon nanotubes and fullerenes are unsuitable as high-capacity (large-gravimetric-d.) hydrogen storage materials because of the weak bonding of hydrogen mols. to the carbon frame. However, coating of such carbon nanostructures with isolated transition metal atoms (e.g., Sc and Ti) can increase the binding energy of hydrogen and lead to high hydrogen storage capacity (e.g., up to 8 wt.% hydrogen). However, this prediction depends on the assumption that the metal atoms coated on the fullerene surface will remain isolated. Using first-principles calcns. based on d. functional theory, it was shown that Ti atoms would prefer to cluster on the C surface, which can significantly alter the nature of hydrogen bonding, thus affecting not only the amt. of stored hydrogen but also their thermodn. and kinetics. Calcns. were made for such fullerides as TiC60 and Ti2C60. Clustering of Ti atoms on the surface, as shown by a T12-cluster on the C60 surface, decreased the hydrogen storage capacity, by removing bonding sites of internal Ti atoms within the cluster.
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219Delley, B. An all-electron numerical method for solving the local density functional for polyatomic molecules. J. Chem. Phys. 1990, 92, 508– 517, DOI: 10.1063/1.458452Google Scholar219https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXht1Ggu7o%253D&md5=89fa4df9819ef5714d3a872cc2e88bc8An all-electron numerical method for solving the local density functional for polyatomic moleculesDelley, B.Journal of Chemical Physics (1990), 92 (1), 508-17CODEN: JCPSA6; ISSN:0021-9606.A method for accurate and efficient local-d.-functional calcns. (LDF) on mols. is described. The method, Dmol for short, uses fast convergent three-dimensional numerical integrations to calc. the matrix elements occurring in the Ritz variation method. The flexibility of the integration technique opens the ways to use the most efficient variational basis sets. A practical choice of numerical basis sets is shown with a built-in capability to reach the LDF dissocn. limit exactly. Dmol includes also an efficient, exact approach for calcg. the electrostatic potential. Results on small mols. illustrate present accuracy and error properties of the method. Computational effort for this method grows to leading order with the cube of the mol. size. Except for the soln. of an algebraic eigenvalue problem, the method can be refined to quadratic growth for large mols.
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220Gong, X.; Kumar, V. Electronic structure and relative stability of icosahedral Al–transition-metal clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 50, 17701– 17704, DOI: 10.1103/PhysRevB.50.17701Google Scholar220https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXivVyltr4%253D&md5=a0ae49ff79f4d8265133f66892433ef3Electronic structure and relative stability of icosahedral Al-transition-metal clustersGong, X. G.; Kumar, VijayPhysical Review B: Condensed Matter (1994), 50 (23), 17701-4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The electronic structure and relative stability of icosahedral Al12M (M = transition metal) clusters have been studied using the d. functional theory within the local spin d. approxn. The calcns. predict large binding energies for clusters with M atom in the middle of a d-series in agreement with the occurrence of Al12W phase in these alloys and provide an insight into the understanding of the stability of Al-M quasicrystals.
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221Pearson, W. B. The crystal chemistry and physics of metals and alloys; Wiley-Interscience: New York, 1972.Google ScholarThere is no corresponding record for this reference.
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222Lu, Q. L.; Chen, L. L.; Wan, J. G.; Wang, G. H. First principles studies on the interaction of O2 with X@Al12 (X = Al-, P+, C, Si) clusters. J. Comput. Chem. 2010, 31, 2804– 2809, DOI: 10.1002/jcc.21573Google Scholar222https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFGqtbzK&md5=321f62a8618d0608a39e67cfd6a5d6ceFirst principles studies on the interaction of O2 with X@Al12 (X = Al-, P+, C, Si) clustersLu, Qi liang; Chen, Li Li; Wan, Jian Guo; Wang, Guang HouJournal of Computational Chemistry (2010), 31 (15), 2804-2809CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)The interaction of O2 with the doped icosahedral X@Al12 (X = Al-, P+, C, Si) clusters with 40 valence electrons were investigated using d. functional theory methods. A different behavior exhibited between Al13- and X@Al12 (X = P+, C, Si) when they interact with O2. The dissocn. of O2 on Al13- is strongly dependent on spin state of oxygen mol. But X@Al12 (X = P+, C, and Si) is not the case. The transform of spin moment from O2 to Al13- is much faster. Small molecularly binding energy and relatively high energy barrier show that these clusters are all reluctant reacts with the ground state O2. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010.
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223Zhao, J.-Y.; Zhao, F.-Q.; Xu, S.-Y.; Ju, X.-H. DFT studies on doping effect of Al12X: adsorption and dissociation of H2O on Al12X clusters. J. Phys. Chem. A 2013, 117, 2213– 2222, DOI: 10.1021/jp309422pGoogle Scholar223https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXivVyhsLc%253D&md5=007263c993d19a97ff339c4c0bd242b4DFT Studies on Doping Effect of Al12X: Adsorption and Dissociation of H2O on Al12X ClustersZhao, Jian-Ying; Zhao, Feng-Qi; Xu, Si-Yu; Ju, Xue-HaiJournal of Physical Chemistry A (2013), 117 (10), 2213-2222CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The adsorption and reaction of H2O mol. on neutral X-centered icosahedronal Al12X clusters (X = Al, Mg, Zn, Ga, Ni, Fe, B, C, Si, P) were investigated by PW91, PBE, and PWC methods. Reaction energies and reaction barriers were detd. The spin states and the doped atoms have important influences on the Al12X geometries, d., electronic properties, and energy d. of reaction between Al12X with a single H2O mol. The energies of the neutral X-centered Al12X are lower than that of surface X-replaced Al12X with the exception of Al12Mg. The H2O dissocn. on the Al12X (X = Mg, Zn, Ga, Ni, Fe) clusters have relatively low activation barriers, but large activation barriers for Al12X (X = B, C, Si, P). The activation barrier of water dissocn. on the singlet Al12Fe cluster is the lowest, whereas the highest barrier is with the Al12C. The reaction of H2O with Al12Fe is the most exothermic. The center-Fe atom can move out to the surface after the adsorption and dissocn. of H2O with an energy barrier of 172 kJ/mol. The results showed that the water dissocn. on the Al12X cluster can be tuned by controllable X doping.
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224Zhao, J.-Y.; Zhao, F.-Q.; Xu, S.-Y.; Ju, X.-H. Theoretical study of the geometries and decomposition energies of CO2 on Al12X: Doping effect of Al12X. J. Mol. Graphics Modell. 2014, 48, 9– 17, DOI: 10.1016/j.jmgm.2013.11.002Google Scholar224https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFGrsLs%253D&md5=8a87ee9c1c301e776deb6d15ea194e6eTheoretical study of the geometries and decomposition energies of CO2 on Al12X: Doping effect of Al12XZhao, Jian-Ying; Zhao, Feng-Qi; Xu, Si-Yu; Ju, Xue-HaiJournal of Molecular Graphics & Modelling (2014), 48 (), 9-17CODEN: JMGMFI; ISSN:1093-3263. (Elsevier Ltd.)The adsorption and decompn. of CO2 mol. on X-centered icosahedronal Al12X clusters (doping atom X = Al, Be, Zn, Fe, Ni, Cu, B, C, Si, P) were investigated by the DFT methods of PW91 and PWC. Adsorption energies, chemisorption energies and energy barriers of physic- and chemisorptions for CO2 were detd. It was found that the doping atoms and spin states have important influences on the Al12X geometries, electronic properties and energies of the adsorption processes. CO2 chemisorption on the Al12C cluster is energetically and kinetically unfavorable. CO2 decompn. on the metallic doping Al12X (X = Fe, Ni, Cu) clusters has relatively low energy barriers. On contrary, the barriers are large when X = B, C, Si and P. The energy barriers for CO2 chemisorption and decompn. on the Al12Fe cluster are 5.23 kJ/mol and 38.53 kJ/mol, resp. These values are the lowest among all the clusters being discussed. The adsorption and decompn. of CO2 on the Al12X cluster can be tuned by X doping.
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225Zhao, J.-Y.; Zhang, Y.; Zhao, F.-Q.; Ju, X.-H. Adsorption of carbon dioxide on Al12X clusters studied by density functional theory: Effect of charge and doping. J. Phys. Chem. A 2013, 117, 12519– 12528, DOI: 10.1021/jp405934wGoogle Scholar225https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslaqu7zJ&md5=759fc07b1ef949a1533b114c737fa3b2Adsorption of Carbon Dioxide on Al12X Clusters Studied by Density Functional Theory: Effect of Charge and DopingZhao, Jian-Ying; Zhang, Yu; Zhao, Feng-Qi; Ju, Xue-HaiJournal of Physical Chemistry A (2013), 117 (47), 12519-12528CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The adsorption of a CO2 mol. on neutral and charged X-centered icosahedron Al12X±z clusters (X = Al, Be, Zn, Ni, Cu, B, P; z = 0, 1) was studied by the d. functional PW91 and PWC methods. Optimized configurations corresponding to physisorption and chemisorption of CO2 were identified. The adsorption energies, activation barriers, and binding energies involving both the physisorption (Al12X±z·CO2-I) and chemisorption (Al12X±z·CO2-II) for CO2 were detd. The chemisorption of a CO2 mol. on the Al12X clusters (X is a metallic doping element) requires relatively low activation barriers. The lowest barrier is with the Al12Be cluster. For the Al12X- clusters, the barriers are all higher than those of the neutral analogs. For the Al12X+ clusters, two corresponding configurations are linked by a low-energy barrier, and CO2 mol. chemisorption on the Al12Be+ cluster has the lowest barrier. The adsorption energies are larger than the energy barriers, which facilitates the chemisorption. Carbon dioxide adsorbed on the Al12X±z clusters can be tuned by controllable X doping and the total no. of valence electrons and suggest the potential application of Al12X±z nanostructures for carbon dioxide capture and activation.
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226Jin, P.; Chen, Y.; Zhang, S. B.; Chen, Z. Interactions between Al12X (X = Al, C, N and P) nanoparticles and DNA nucleobases/base pairs: Implications for nanotoxicity. J. Mol. Model. 2012, 18, 559– 568, DOI: 10.1007/s00894-011-1085-5Google Scholar226https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVCjsb8%253D&md5=0343e8e9edd3a00d89f9766f8034b1b1Interactions between Al12X (X = Al, C, N and P) nanoparticles and DNA nucleobases/base pairs: implications for nanotoxicityJin, Peng; Chen, Yongsheng; Zhang, Shengbai B.; Chen, ZhongfangJournal of Molecular Modeling (2012), 18 (2), 559-568CODEN: JMMOFK; ISSN:0948-5023. (Springer)The interactions between neutral Al12X(I h ) (X = Al, C, N and P) nanoparticles and DNA nucleobases, namely adenine (A), thymine (T), guanine (G) and cytosine (C), as well as the Watson-Crick base pairs (BPs) AT and GC, were investigated by means of d. functional theory computations. The Al12X clusters can tightly bind to DNA bases and BPs to form stable complexes with neg. binding Gibbs free energies at room temp., and considerable charge transfers occur between the bases/BPs and the Al12X clusters. These strong interactions, which are also expected for larger Al nanoparticles, may have potentially adverse impacts on the structure and stability of DNA and thus cause its dysfunction.
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227Gong, X.; Chiarotti, G. L.; Parrinello, M.; Tosatti, E. α-gallium: A metallic molecular crystal. Phys. Rev. B: Condens. Matter Mater. Phys. 1991, 43, 14277– 14280, DOI: 10.1103/PhysRevB.43.14277Google Scholar227https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXksFOlt78%253D&md5=da7aff90975e5a8c97726395a0747d85α-Gallium: a metallic molecular crystalGong, X. G.; Chiarotti, Guido L.; Parrinello, M.; Tosatti, E.Physical Review B: Condensed Matter and Materials Physics (1991), 43 (17), 14277-80CODEN: PRBMDO; ISSN:0163-1829.A first-principles theor. study is presented of the at. and electronic structures, and of the zero-temp. phases of Ga. The picture of α-Ga that emerges is of a metallic mol. crystal with a strong Ga2 covalent bond and weaker intermol. forces. The picture is supported in detail by the charge d., the electronic structure, and differential bond stretching under pressure. Anomalous features of α-Ga, such as the Knight shift, anisotropic Fermi-surface effects, and optical absorption find a consistent explanation. Accurate x-ray measurements should reveal the Ga2 covalent bonds.
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228Chacko, S.; Joshi, K.; Kanhere, D.; Blundell, S. Why do gallium clusters have a higher melting point than the bulk?. Phys. Rev. Lett. 2004, 92, 135506, DOI: 10.1103/PhysRevLett.92.135506Google Scholar228https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXivVegurY%253D&md5=b6ab14fe363bf9ba24a694190dd9bf7cWhy Do Gallium Clusters Have a Higher Melting Point than the Bulk?Chacko, S.; Joshi, Kavita; Kanhere, D. G.; Blundell, S. A.Physical Review Letters (2004), 92 (13), 135506/1-135506/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)D. functional mol. dynamical simulations have been performed on Ga17 and Ga13 clusters to understand the recently obsd. higher-than-bulk melting temps. in small gallium clusters [G. A. Breaux et al., Phys. Rev. Lett. 91, 215508 (2003)]. The specific-heat curve, calcd. with the multiple-histogram technique, shows the melting temp. to be well above the bulk m.p. of 303 K, viz., around 650 and 1400 K for Ga17 and Ga13, resp. The higher-than-bulk melting temps. are attributed mainly to the covalent bonding in these clusters, in contrast with the covalent-metallic bonding in the bulk.
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229Henry, D. J. Structures and stability of doped gallium nanoclusters. J. Phys. Chem. C 2012, 116, 24814– 24823, DOI: 10.1021/jp307555rGoogle Scholar229https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1ent77P&md5=caecb1311bb0bcbed379fc6d074ec273Structures and Stability of Doped Gallium NanoclustersHenry, David J.Journal of Physical Chemistry C (2012), 116 (46), 24814-24823CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The stability and reactivity of metal nanoclusters are critically dependent on the valence electronic configuration of the cluster. Many "magic" electronic configurations are inaccessible for pure trivalent metal clusters. However, doping is one method by which the electronic configuration and properties of a cluster can be significantly modified or even tailored. D. functional theory (DFT-PBE0) is used in this study to investigate the structures, stabilities and electronic properties of doped gallium nanoclusters, Ga12X (X = B, C, N, Al, Si, P, Ga, Ge, and As). In all cases doping of the cluster leads to increased stability relative to Ga13. Stabilization is largely due to electronic contributions, although for many of the clusters the dopant also induces a small increase in the stability of the Ga12 framework. Generally, the endohedrally doped isomers are either lower in energy or close in energy to the isomers with the dopant at the surface of the cluster. Endohedral Ga12C is the most stable cluster and exhibits the most jellium-like orbital structure. Trends in vertical ionization potentials and electron affinities can be explained in terms of the interactions in frontier orbitals and generally adhere to the predictions of the jellium model.
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230Guo, L. Computational investigation of GanAl (n = 1–15) clusters by the density-functional theory. Comput. Mater. Sci. 2009, 45, 951– 958, DOI: 10.1016/j.commatsci.2009.01.001Google Scholar230https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlslClurs%253D&md5=6251a70c909626773825f35e1dbd8cfdComputational investigation of GanAl (n =1-15) clusters by the density-functional theoryGuo, LingComputational Materials Science (2009), 45 (4), 951-958CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)Low-lying equil. geometric structures of aluminum-doped gallium cluster GanAl (n = 1-15) clusters obtained by an all-electron linear combination of AO approach, within spin-polarized d. functional theory, are reported. The binding energy, dissocn. energy, and stability of these clusters are studied with the three-parameter hybrid generalized gradient approxn. (GGA) due to Becke-Lee-Yang-Parr (B3LYP). Ionization potentials, electron affinities, hardness, and static polarizabilities are calcd. for the ground-state structures within the same method. The growth pattern for GanAl (n = 1-15) clusters is Al-substituted Gan + 1 clusters and it keeps the similar frameworks of the most stable Gan + 1 clusters except for Ga8Al and Ga13 Al clusters. The Al atom substituted the surface atom of the Gan + 1 clusters for n < 12. Starting from n = 12, the Al atom completely falls into the center of the Ga-frame. The Al atom substituted the center atom of the Gan + 1 clusters to form the Al-encapsulated Gan geometries for n > 12. The odd-even oscillations from GanAl (n = 5) in the dissocn. energy, the second-order energy differences, the HOMO-LUMO gaps, the ionization potential, the electron affinity, and the hardness are more pronounced. The stability anal. based on the energies clearly shows the clusters from n = 5 with an even no. of valence electrons are more stable than clusters with odd no. of valence electrons.
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231Yuan, G.; Lu, P.; Han, L.; Yu, Z.; Shen, Y.; Zhao, L.; Liu, Y. Structural and electronic properties of neutral clusters Ga12X (X = C, Si, Ge, Sn, and Pb) and their anions from first principles. Phys. B 2011, 406, 3498– 3501, DOI: 10.1016/j.physb.2011.06.034Google Scholar231https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXos1antbk%253D&md5=4a736bcc57ed4abda65dafab6a5ff909Structural and electronic properties of neutral clusters Ga12X (X=C, Si, Ge, Sn, and Pb) and their anions from first principlesYuan, Guifang; Lu, Pengfei; Han, Lihong; Yu, Zhongyuan; Shen, Yue; Zhao, Long; Liu, YuminPhysica B: Condensed Matter (Amsterdam, Netherlands) (2011), 406 (18), 3498-3501CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)The structural and electronic properties of neutral and neg. charged Ga12X (X=C, Si, Ge, Sn, and Pb) clusters are calcd. by the first-principles method. The results show that the most stable symmetry depends on the doped atom rather than the geometry structure. However, the geometry symmetry plays an important role in calcg. the energy gap. In addn., in the anionic clusters, the added electron would reduce the energy gap by about 0.4 eV. As for the d. of states (DOS), clusters with the same symmetry show a similar trend of DOS. The major impact on DOS by adding an electron is the occurrence of relative energy shift.
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232Song, B.; Yao, C.-H.; Cao, P.-L. Density-functional study of structural and electronic properties of GanN (n = 1–19) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 035306, DOI: 10.1103/PhysRevB.74.035306Google Scholar232https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XotFWhs7k%253D&md5=91b578c1ef1e92ead0d44125a9dfc6d1Density-functional study of structural and electronic properties of GanN (n = 1-19) clustersSong, Bin; Yao, Chang-Hong; Cao, Pei-linPhysical Review B: Condensed Matter and Materials Physics (2006), 74 (3), 035306/1-035306/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The lowest-energy geometries and electronic-structure properties were obtained for GanN (n = 1-19) clusters within the d.-functional theory using the generalized gradient approxn. for the exchange-correlation potential. The resulting geometries show that the nitrogen atom tends to occupy an inside position for n ≤ 10, but prefers a peripheral position with a bulk-like coordination beyond n = 10. The stability was investigated by analyzing the binding energy per atom and the second difference in energy. The clusters Ga3N, Ga7N, and Ga15N exhibit particularly higher stability. The bonding properties were analyzed by calcg. the Mulliken charges and Ga-N distances. The N in GanN clusters is less ionic than that in bulk GaN (wurtzite phase). The HOMO-LUMO gap, the vertical ionization potential, and the vertical electron affinity form an even-odd alternating pattern with increasing cluster size. In general, the vertical ionization potential tends to lower as the cluster size increases, while the vertical electron affinity tends to increase as the cluster size increases.
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233Akutsu, M.; Koyasu, K.; Atobe, J.; Miyajima, K.; Mitsui, M.; Nakajima, A. Electronic properties of Si and Ge atoms doped in clusters: InnSi m and InnGem. J. Phys. Chem. A 2007, 111, 573– 577, DOI: 10.1021/jp065921wGoogle Scholar233https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXjtVWqtQ%253D%253D&md5=a9aa7b25ac66ef14f1388311ccc2993eElectronic Properties of Si and Ge Atoms Doped In Clusters: InnSim and InnGemAkutsu, Minoru; Koyasu, Kiichirou; Atobe, Junko; Miyajima, Ken; Mitsui, Masaaki; Nakajima, AtsushiJournal of Physical Chemistry A (2007), 111 (4), 573-577CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Electronic properties of Si and Ge atom doped In clusters, InnSim and InnGem, were studied by photoionization spectroscopy of the neutrals and photoelectron spectroscopy of the anions. Size dependence of ionization energy and electron affinity for InnSi1 and InnGe1 exhibit pronounced even-odd alternation at cluster sizes of n = 10-16, as compared to those for pure Inn clusters. Symmetry lowering with the doped atom of Si or Ge results in undegeneration of electronic states in the 1d shell formed by monovalent In atoms.
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234Nakajima, A.; Hoshino, K.; Sugioka, T.; Naganuma, T.; Taguwa, T.; Yamada, Y.; Watanabe, K.; Kaya, K. Electronic shell structure of indium-sodium (InnNam) bimetallic clusters examined by their ionization potentials and mass distributions. J. Phys. Chem. 1993, 97, 86– 90, DOI: 10.1021/j100103a016Google Scholar234https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXis1Wiu7g%253D&md5=ada82c1f80a8f482d170e734da17ec67Electronic shell structure of indium-sodium (InnNam) bimetallic clusters examined by their ionization potentials and mass distributionsNakajima, Atsushi; Hoshino, Kuniyoshi; Sugioka, Tsuneyoshi; Naganuma, Takashi; Taguwa, Tetsuya; Yamada, Yoshiyuki; Watanabe, Katsura; Kaya, KojiJournal of Physical Chemistry (1993), 97 (1), 86-90CODEN: JPCHAX; ISSN:0022-3654.Indium-sodium (InnNam) bimetallic clusters were produced by two independent laser vaporization methods. Ionization potentials (IPs) of the InnNam clusters were measured up to m = 2 using a tunable UV laser combined with a time-of-flight (TOF) mass spectrometer. At small sizes (n = 3-15), the ionization potentials decrease by 0.1-0.8 eV with the addn. of Na atoms(s), whereas the IPs of larger Inn (15 ≤ n ≤ 27) clusters do not decrease with Na addn. Moreover, IPs of In7Na1 and In13Na1 clusters are higher than those of In7 and In13, and the IP increments can be explained by electronic shell closings of the 1p (8e) and 2p shell (40 e), where In atoms in the clusters are monovalent and trivalent, resp. The electronic shell structure was also examd. by a magic no. in mass distributions of InnNam- cluster anions; the In12Na3- cluster can be obsd. as magic nos., corresponding to the 2p shell closing. In contrast, no electronic shell structure is obsd. in pure Inn clusters around n = 13. These results indicate that Na atom addn. can induce s/p hybridization in the Inn clusters. We also present mass distributions of aluminum-sodium cluster anions, AlnNam-, whose feature can be understood by the electronic shell model.
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235Liu, Y.; Deng, K.; Yuan, Y.; Chen, X.; Wu, H.; Wang, X. Structural and electronic properties of neutral clusters In12X (X = C, Si, Ge, and Sn) and their anions from first principles. Chem. Phys. Lett. 2009, 469, 321– 324, DOI: 10.1016/j.cplett.2009.01.018Google Scholar235https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1antb4%253D&md5=8ca10cdfe9bf8ff5ed5f3bbac117c75aStructural and electronic properties of neutral clusters In12X (X=C, Si, Ge, and Sn) and their anions from first principlesLiu, Yuzhen; Deng, Kaiming; Yuan, Yongbo; Chen, Xuan; Wu, Haiping; Wang, XinChemical Physics Letters (2009), 469 (4-6), 321-324CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The structural and electronic properties of In12X (X = C, Si, Ge, Sn) and their anions were studied using the d. functional theory at BLYP and B3LYP levels. The equil. geometries of In 12 X (X = Si, Ge, and Sn) and their anions favor the pseudo D 5 h structures, while those of In 12 C and its anion tend to form C s ones. The calcd. adiabatic electron affinities of In 12 Si and In 12 Ge are 2.01 and 2.04 eV, resp., in good agreement with the available exptl. data. The magnetic moments of the ground state In 12 X are all zero, indicating that they have closed shell electronic structures. Thus, indium behaves as a trivalent atom in the clusters.
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236Henning, R. W.; Corbett, J. D. Formation of isolated nickel-centered gallium clusters in Na10Ga10Ni and a 2-D network of gallium octahedra in K2Ga3. Inorg. Chem. 1999, 38, 3883– 3888, DOI: 10.1021/ic990335lGoogle Scholar236https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXks12htbY%253D&md5=4a5c66fcbd1d20851613d518d80bfbedFormation of Isolated Nickel-Centered Gallium Clusters in Na10Ga10Ni and a 2-D Network of Gallium Octahedra in K2Ga3Henning, Robert W.; Corbett, John D.Inorganic Chemistry (1999), 38 (17), 3883-3888CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Exploration of the Na-Ga-Ni system revealed a new compd. contg. the isolated Ga clusters Ga10Ni10-. Single-crystal x-ray diffraction studies of Na10Ga10Ni (space group Pnma, Z = 12, a 13.908(3), b 28.146(6), c 16.286(4) Å) show it to be isostructural with K10In10Ni. The compd. contains two similar naked Ga clusters as distorted, tetracapped trigonal prismatic units that are centered by Ni. The Na atoms serve to isolate the clusters from each other as well as to provide the cluster with a closed shell configuration of electrons. This is the first isolated Ga cluster in an alkali-metal system that is centered. MO calcns. on the cluster are also reported. The crystal structure of K2Ga3 (space group I4/mmm, Z = 4, a 6.1382(3), c 14.815(1) Å) also is isostructural with A2In3 (A = Rb, Cs). This contains Ga64- octahedra interconnected through the waist atoms into layers ∞2[Ga64-], with octahedra in adjacent layers sitting in the depressions of the first. The K atoms have characteristic roles except for an unusually short K-K contact (3.242(4) Å) across the layer. Magnetic measurements indicate that both phases are diamagnetic and consistent with the Zintl formalism.
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237Sevov, S. C.; Corbett, J. D. Potassium indium zinc compound K8In10Zn: Interstitially-stabilized analogs of early-transition-metal halide clusters. Inorg. Chem. 1993, 32, 1059– 1061, DOI: 10.1021/ic00059a001Google Scholar237https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXhsF2qs7o%253D&md5=ca57c87ab34902a97f6cfde6942a941bPotassium indium zinc compound K8In10Zn: interstitially-stabilized analogs of early-transition-metal halide clustersSevov, Slavi C.; Corbett, John D.Inorganic Chemistry (1993), 32 (7), 1059-61CODEN: INOCAJ; ISSN:0020-1669.K8In10Zn was prepd. by fusion of the elements at 600°. X-ray single crystal anal. shows the structure to consist of Zn encapsulated in a bicapped square antiprism polyhedron of In with ∼D4d symmetry. The Zn atom is nearly equidistant from all In atoms (av. Zn-In = 2.836 Å). The In-In av. bond distance is 3.072 Å, with the In...In distances on the edges of the square faces 0.57 Å longer. The stability of the structure is explained using EHMO calcns. Magnetic susceptibility data was detd. and compared to K8In11.
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238Sevov, S. C.; Corbett, J. D. K10In10Z (Z = Ni, Pd, Pt): Zintl phases containing isolated decaindium clusters centered by transition elements. J. Am. Chem. Soc. 1993, 115, 9089– 9094, DOI: 10.1021/ja00073a026Google Scholar238https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlvFCnurc%253D&md5=523a394105fd463bf34d44bc6939d08dK10In10Z (Z = Ni, Pd, Pt): Zintl phases containing isolated decaindium clusters centered by transition elementsSevov, Slavi C.; Corbett, John D.Journal of the American Chemical Society (1993), 115 (20), 9089-94CODEN: JACSAT; ISSN:0002-7863.The isostructural K10In10Z (Z = Ni, Pd, Pt) are obtained in high yield by slowly cooling the appropriate fused mixt. in welded Ta. They occur as orthorhombic, space group Pnma, Z = 12, with a 15.948(6), 16.043(6), 16.056(3), b 32.565(6), 32.73(1), 32.692(1), and c 18.822(3) , 18.895(5), 18.896(3) Å for the Ni, Pd, and Pt derivs., resp. The structure of K10In10Ni was refined by single crystal means (R = 0.029, Rw = 0.033) and is constructed from close-packed layers of Ni-centered In10 clusters that are sepd. by K ions both within and between the cluster layers. The compds. have large resistivities at room temp. by 2-probe methods and are diamagnetic, with no moments on the transition metals. The geometry of the clusters can be derived from an ideal tetracapped trigonal prism (C3v) of In centered by Z through axial compression along the 3-fold axis and opening of the capped triangular face so as to yield substantially equal Ni-In distances. The clusters are related to Sb73-, etc. Charge-consistent EHMO calcns. show that the Ni-centered cluster has a closed shell with 2n = 20 skeletal electrons, only the s and p orbitals on the interstitial mixing with appropriate cluster orbitals. The d orbitals on Ni do not appear to participate significantly, presumably because they are fully reduced (lie too low) relative to In p (d(In-Ni) ∼ 2.8 Å). This means that Ni, Pd, and Pt behave as quasi-main-group elements.
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239Handschuh, H.; Ganteför, G.; Kessler, B.; Bechthold, P. S.; Eberhardt, W. Stable configurations of carbon clusters: Chains, rings, and fullerenes. Phys. Rev. Lett. 1995, 74, 1095– 1098, DOI: 10.1103/PhysRevLett.74.1095Google Scholar239https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjs1KisLw%253D&md5=6c0ffa3eda1e2034d83adc43e825595dStable configurations of carbon clusters: chains, rings, and fullerenesHandschuh, H.; Gantefoer, G.; Kessler, B.; Bechthold, P. S.; Eberhardt, W.Physical Review Letters (1995), 74 (7), 1095-8CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)A systematic study of the size dependence of the vibrational modes of carbon clusters with 5-70 atoms is presented. The vibrational frequencies are measured using photoelectron spectroscopy of mass-sepd. neg. charged clusters. The clusters are carefully annealed. Only the most stable isomers are present in the beam after the annealing. Obsd. vibrational modes can be assigned to four dominant isomeric structures: linear chains (C5-, C7-, and C9-), monocyclic rings (C10-, C12-, C14-, C16- and C18-), bicyclic rings (C20-, C24-, and C28-), and fullerenes (even n > C30-).
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240Martin, J. M. C28: The smallest stable fullerene?. Chem. Phys. Lett. 1996, 255, 1– 6, DOI: 10.1016/0009-2614(96)00354-5Google Scholar240https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XjsVOnu7c%253D&md5=f23c3e01cd6f9aa2f6fd28ed14745143C28: the smallest stable fullerene?Martin, Jan M. L.Chemical Physics Letters (1996), 255 (1,2,3), 1-6CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)The relative energies of different structures of C28 have been studied by d. functional theory using different exchange-correlation functionals, including two with exact exchange contributions. A fullerene structure with Td symmetry (5A2 state) is found to be by far the most stable structure, followed at 4-6 eV by a graphite sheet fragment and at 5-7 eV by a C14h ring. Other structures lie still higher in energy. An IR spectrum of fingerprint quality has been computed for the fullerene and should enable its exptl. identification.
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241Kroto, H. W. The stability of the fullerenes Cn, with n = 24, 28, 32, 36, 50, 60 and 70. Nature 1987, 329, 529– 531, DOI: 10.1038/329529a0Google Scholar241https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXksFCjsrg%253D&md5=a7bbb6ca1020565379654bce35af2dc3The stability of the fullerenes Cn, with n = 24, 28, 32, 36, 50, 60 and 70Kroto, H. W.Nature (London, United Kingdom) (1987), 329 (6139), 529-31CODEN: NATUAS; ISSN:0028-0836.Empirical chem. and geodesic rules are presented that relate the stability of carbon cage compds. mainly to the disposition of pentagonal rings or directly fused pentagonal ring configurations. The rules yield magic cluster nos. consistent with observation and in particular predict that fullerenes contg. 24, 28, 32, 36, 50, 60, and 70 carbons should have enhanced stability relative to near neighbors. These results support the proposals that closed hollow cages form when carbon nucleates in the vapor phase, and that C60 is a truncated icosahedron.
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242Chen, Z.; Jiao, H.; Bühl, M.; Hirsch, A.; Thiel, W. Theoretical investigation into structures and magnetic properties of smaller fullerenes and their heteroanalogues. Theor. Chem. Acc. 2001, 106, 352– 363, DOI: 10.1007/s002140100284Google Scholar242https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovFOisrw%253D&md5=9e4ca884ccfb2dbda7cc0076d58b265aTheoretical investigation into structures and magnetic properties of smaller fullerenes and their heteroanaloguesChen, Zhongfang; Jiao, Haijun; Buhl, Michael; Hirsch, Andreas; Thiel, WalterTheoretical Chemistry Accounts (2001), 106 (5), 352-363CODEN: TCACFW; ISSN:1432-881X. (Springer-Verlag)The smaller fullerenes, C20, C24, C28, C32, C36, C40 and C50, their hydrogenation products and selected B-, N- and P-doped analogs have been investigated systematically at the B3LYP/6-31G* d. functional level of theory. The degree of spherical electron delocalization is evaluated by using the computed nucleus-independent chem. shifts (NICS) at the cage center and the individual ring centers of interest. The calcd. NMR chem. shifts and the NICS values at the cage center, which can be accessed by endohedral 3He chem. shifts, should provide a basis for further exptl. characterization of these compds.
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243Diener, M. D.; Smith, C. A.; Veirs, D. K. Anaerobic preparation and solvent-free separation of uranium endohedral metallofullerenes. Chem. Mater. 1997, 9, 1773– 1777, DOI: 10.1021/cm960540oGoogle Scholar243https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXltV2qsbw%253D&md5=8248c84403f03b391f7f80de70153caeAnaerobic Preparation and Solvent-Free Separation of Uranium Endohedral MetallofullerenesDiener, Michael D.; Smith, Coleman A.; Veirs, D. KirkChemistry of Materials (1997), 9 (8), 1773-1777CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)Safe prodn., handling, and sepn. of depleted uranium endohedral metallofullerenes in an oxygen-free environment is demonstrated. Films of C60, C70, and M@C60 are produced by subliming fullerenes from arc-produced soot onto a mass spectrometry target (with ∼1% impurities of higher fullerenes). Also, films consisting of higher fullerenes (empty and full) and mostly devoid of C60 or C70 are made by subliming at higher temps. The temp. of the soot must be uniform and held const. during sublimation to produce high-quality films. M@C60 requires a slightly higher temp. for sublimation than empty C60, the likely result of stronger interactions between M@C60 and its surroundings in the soot.
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244Akiyama, K.; Zhao, Y.; Sueki, K.; Tsukada, K.; Haba, H.; Nagame, Y.; Kodama, T.; Suzuki, S.; Ohtsuki, T.; Sakaguchi, M. Isolation and characterization of light actinide metallofullerenes. J. Am. Chem. Soc. 2001, 123, 181– 182, DOI: 10.1021/ja005618nGoogle Scholar244https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXoslKjs7w%253D&md5=2cfd64b33ea0bc339d8905d44506ff31Isolation and Characterization of Light Actinide MetallofullerenesAkiyama, Kazuhiko; Zhao, Yuliang; Sueki, Keisuke; Tsukada, Kazuaki; Haba, Hiromitsu; Nagame, Yuichirou; Kodama, Takeshi; Suzuki, Shinzou; Ohtsuki, Tsutomu; Sakaguchi, Masahiko; Kikuchi, Koichi; Katada, Motomi; Nakahara, HiromichiJournal of the American Chemical Society (2001), 123 (1), 181-182CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The arc-discharge prepn. of uranium, neptunium and americium metallofullerenes is reported. The major uranium species formed are U@C82 and U2@C80 which were isolated by a 2-step HPLC sepn. method and identified by TOF/MS measurements. The UV/vis/NIR absorption spectrum for U@C82 is also reported. Similarities in retention times suggest that the major neptunium and americium species are Np@C82 and Am@C82, resp.
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245Dunk, P. W.; Kaiser, N. K.; Mulet-Gas, M.; Rodríguez-Fortea, A.; Poblet, J. M.; Shinohara, H.; Hendrickson, C. L.; Marshall, A. G.; Kroto, H. W. The smallest stable fullerene, M@C28 (M = Ti, Zr, U): Stabilization and growth from carbon vapor. J. Am. Chem. Soc. 2012, 134, 9380– 9389, DOI: 10.1021/ja302398hGoogle Scholar245https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XlvV2ktLw%253D&md5=09c1e98a07115f099ace15d06c22b0edThe Smallest Stable Fullerene, M@C28 (M = Ti, Zr, U): Stabilization and Growth from Carbon VaporDunk, Paul W.; Kaiser, Nathan K.; Mulet-Gas, Marc; Rodriguez-Fortea, Antonio; Poblet, Josep M.; Shinohara, Hisanori; Hendrickson, Christopher L.; Marshall, Alan G.; Kroto, Harold W.Journal of the American Chemical Society (2012), 134 (22), 9380-9389CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The smallest fullerene to form in condensing carbon vapor has received considerable interest since the discovery of Buckminsterfullerene, C60. Smaller fullerenes remain a largely unexplored class of all-carbon mols. that are predicted to exhibit fascinating properties due to the large degree of curvature and resulting highly pyramidalized carbon atoms in their structures. However, that curvature also renders the smallest fullerenes highly reactive, making them difficult to detect exptl. Gas-phase attempts to investigate the smallest fullerene by stabilization through cage encapsulation of a metal were hindered by the complexity of mass spectra that result from vaporization expts. which include nonfullerene clusters, empty cages, and metallofullerenes. The authors use high-resoln. FT-ICR mass spectrometry to overcome that problem and investigate formation of the smallest fullerene using a pulsed laser vaporization cluster source. Here, the authors report that the C28 fullerene stabilized by encapsulation with an appropriate metal forms directly from carbon vapor as the smallest fullerene under the authors' conditions. Its stabilization is investigated, and M@C28 is formed by a bottom-up growth mechanism and is a precursor to larger metallofullerenes. In fact, apparently the encapsulating metal species may catalyze or nucleate endohedral fullerene formation.
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246Makurin, Y. N.; Sofronov, A. A.; Gusev, A. I.; Ivanovsky, A. L. Electronic structure and chemical stabilization of C28 fullerene. Chem. Phys. 2001, 270, 293– 308, DOI: 10.1016/S0301-0104(01)00342-1Google Scholar246https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXltFyrsbY%253D&md5=88f7826f38f7d6913f1c0f8d4a241c26Electronic structure and chemical stabilization of C28 fullereneMakurin, Y. N.; Sofronov, A. A.; Gusev, A. I.; Ivanovsky, A. L.Chemical Physics (2001), 270 (2), 293-308CODEN: CMPHC2; ISSN:0301-0104. (Elsevier Science B.V.)The ab initio d. functional theory (DFT) method was used to carry out self-consistent calcns. of the electronic structure of "mixed" C28-based fullerenes: (1) heterofullerenes C24N4, C24B4; (2) exohedral complexes C28M4 (M = H, F, Cl, Br); (3) endohedral complexes M28 with 2p-atoms (M = B, C, N, O); and (4) endohedral complexes M28 with 3d-atoms (M = Sc, Ti, V, Cr, Fe, Cu). The electronic structure, charge distributions, chem. bonding and comparative stability in the series of these complexes are analyzed. The optimum chem. stability conditions are met for: (1) C24B4 from the series of heterofullerenes; (2) C28F4 from the series of exocomplexes; (3) B28 from the series of endocomplexes with participation of 2p-atoms; (4) Ti28 from the series of endocomplexes with participation of 3d-atoms. Possible mechanisms of C28 stabilization are discussed depending on the method of functionalization and the type of a "guest" atom.
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247Pederson, M. R.; Laouini, N. Covalent container compound: Empty, endohedral, and exohedral C28 complexes. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 48, 2733– 2737, DOI: 10.1103/PhysRevB.48.2733Google Scholar247https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXmtFWhs7Y%253D&md5=dd7781fc1f0b4d02ce6b9438caaa3d22Covalent container compound: empty, endohedral, and exohedral C28 fullerene complexesPederson, Mark R.; Laouini, NozhaPhysical Review B: Condensed Matter and Materials Physics (1993), 48 (4), 2733-7CODEN: PRBMDO; ISSN:0163-1829.Results are given for quasidynamic local-d. simulations on a small fullerene complex (C28), three endohedral complexes (C28@C, C28@Zr, and C28@Ti), a C atom bound to the corner of the C28 mol., and C28H4. This mol. forms spontaneously from a 29-atom diamond crystallite, and, under proper circumstances, is a covalent container compd. Upon encapsulation of a Zr atom, 12.6 eV of energy is liberated leading to an unreactive closed-shell C28@Zr mol. The open-shell structure of the empty mol. leads to a reactive yet relatively stable building block, which might be useful for synthesis of new metastable forms of carbon-based materials. Electronic structures, ionization energies, electron affinities, equil. geometries, and bare Hubbard U interaction parameters are presented.
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248Jackson, K.; Kaxiras, E.; Pederson, M. R. Electronic states of group-IV endohedral atoms in C28. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 48, 17556– 17561, DOI: 10.1103/PhysRevB.48.17556Google Scholar248https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhtFOisbw%253D&md5=855b8aeba2bdc4f8fceeae251c2f7571Electronic states of group-IV endohedral atoms in C28Jackson, Koblar; Kaxiras, Efthimios; Pederson, Mark R.Physical Review B: Condensed Matter and Materials Physics (1993), 48 (23), 17556-61CODEN: PRBMDO; ISSN:0163-1829.The authors have systematically studied the interaction between the C28 fullerene mol. and the group-IVA endohedral atoms C, Si, Ge, and Sn, using state-of-the-art electronic structure and total-energy calcns. based on d.-functional theory. The authors find no covalent bonding between these atoms and the fullerene cage. The nature of the cage-atom interaction involves charge transfer from the endohedral atom the cage which produces weak, mostly ionic binding. The degree of charge transfer increases with the at. no. of the endohedral atom. By comparing the electronic structure of the group-IVA endohedral cage compds. to Zr@C28 (a group-IVB endohedral), the authors find that the latter bonds strongly to the cage due to covalent interaction between the Zr 4d states and the C28 states. The authors extrapolate the trends found for the group-IV endohedrals to suggest other possibly systems and to provide insight to the stability of the exptl. obsd. U@C28 complex.
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249Guo, T.; Smalley, R. E.; Scuseria, G. E. Ab initio theoretical predictions of C28, C28H4, C28F4,(Ti@C28)H4, and M@C28 (M = Mg, Al, Si, S, Ca, Sc, Ti, Ge, Zr, and Sn). J. Chem. Phys. 1993, 99, 352– 359, DOI: 10.1063/1.465758Google Scholar249https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlvVyqsrk%253D&md5=728482184666009e62dfa22f515bb82fAb initio theoretical predictions of C28 fullerene, hydrofullerene, fluorofullene, and endohedral titanium hydrofullerene (C28, C28H4, C28F4, and (Ti@C28)H4), and C28 endohedral metal or nonmetal fullerenes (M@C28 (M = Mg, Al, Si, S, Ca, Sc, Ti, Ge, Zr, and Sn))Guo, Ting; Smalley, Richard E.; Scuseria, Gustavo E.Journal of Chemical Physics (1993), 99 (1), 352-9CODEN: JCPSA6; ISSN:0021-9606.The authors studied the electronic structures, equil. geometries, and binding energies of the title mols. at the SCF-Hartree-Fock level of theory employing basis sets of double-zeta quality. The empty C28 fullerene has a 5A2 open-shell ground state and behaves as a sort of hollow super-atom with an effective valence of 4, both toward the outside and inside of the carbon cage. The C28H4 and C28F4 should be stable mols. The possibility of simultaneous bonding from the inside and outside of the C28 shell, as in (Ti@C28)H4, is also explored. The binding energy of the M@C28 species is a good indicator of the success in exptl. trapping the metal atoms (M) inside the fullerene cage. Elements with electronegativities smaller than 1.54 should form endohedral fullerenes larger than a min. size which depends on the ionic radius of the trapped atom. This qual. model, correctly reproduces the available exptl. evidence on endohedral fullerenes.
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250Jackson, K.; Kaxiras, E.; Pederson, M. R. Bonding of endohedral atoms in small carbon fullerenes. J. Phys. Chem. 1994, 98, 7805– 7810, DOI: 10.1021/j100083a010Google Scholar250https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXkvFansbY%253D&md5=2f0ce1c9b82ebe30a18a1b5837507539Bonding of Endohedral Atoms in Small Carbon FullerenesJackson, Koblar; Kaxiras, Efthimios; Pederson, Mark R.Journal of Physical Chemistry (1994), 98 (32), 7805-10CODEN: JPCHAX; ISSN:0022-3654.A simple model for understanding the bonding of endohedral atoms in small fullerene cages is presented, which is based on their approx. spherical shape. Previous work has shown that the one-electron wave functions of a fullerene cage can be assigned angular-momentum quantum nos., which describe their overall angular character. These quantum nos. form the basis for approx. selection rules, which govern the bonding with endohedral atoms. With this model, the authors successfully address the very different bonding of various tetravalent elements in C28, and the remarkably strong bonding of U in this small fullerene. The authors also make several specific predictions regarding the stability of other endohedral complexes.
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251Ryzhkov, M. V.; Medvedeva, N. I.; Delley, B. Electronic structures of endohedral fullerenes with scandium, titanium and iron atoms and metal-carbon clusters. Polyhedron 2017, 134, 376– 384, DOI: 10.1016/j.poly.2017.06.032Google Scholar251https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFartrzP&md5=4959355c0c2e3181730c323f17d1cb93Electronic structures of endohedral fullerenes with scandium, titanium and iron atoms and metal-carbon clustersRyzhkov, M. V.; Medvedeva, N. I.; Delley, B.Polyhedron (2017), 134 (), 376-384CODEN: PLYHDE; ISSN:0277-5387. (Elsevier Ltd.)The electronic structures of the endohedral forms of the C28, C40, C60 and C80 fullerenes encapsulating the 3d-atoms Sc, Ti and Fe, and in the case of C80 with M2C2 clusters (M = Sc, Ti, Fe) were investigated using the ab initio Dmol3 method. For the C60 and C80 cages, we found preferable positions of the metal atoms and their carbon clusters near the internal surface of the fullerene shell. The anal. of the formation energy variation and the role of the magnetic state of 3d-atoms is presented.
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252Dunlap, B. I.; Haeberlen, O. D.; Roesch, N. Asymmetric localization of titanium in carbon molecule (C28). J. Phys. Chem. 1992, 96, 9095– 9097, DOI: 10.1021/j100202a003Google Scholar252https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XmsVSis7g%253D&md5=85e82ee77be6c1908215422bfafa6541Asymmetric localization of titanium in carbon molecule (C28)Dunlap, Brett I.; Haeberlen, Oliver D.; Roesch, NotkerJournal of Physical Chemistry (1992), 96 (23), 9095-7CODEN: JPCHAX; ISSN:0022-3654.Linear combination of GTO (LCGTO) local d. functional (LDF) calcns. on the Ti.C28 endohedral fullerene complex suggest that the Ti atom is too small to fill completely the interior vol. of the tetrahedral C28 fullerene; the Ti atom is attracted a significant distance, 0.5 Å, toward one of the four corners of the tetrahedron. This may be one reason why Ti@C28 is exptl. less abundant and stable than U.C28, which has a larger endohedral atom.
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253Skwara, B.; Góra, R. W.; Zalesny, R.; Lipkowski, P.; Bartkowiak, W.; Reis, H.; Papadopoulos, M. G.; Luis, J. M.; Kirtman, B. Electronic structure, bonding, spectra, and linear and nonlinear electric properties of Ti@C28. J. Phys. Chem. A 2011, 115, 10370– 10381, DOI: 10.1021/jp206331nGoogle Scholar253https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtV2ntL3K&md5=23eb87d8cf5cf343333aa4ac047ca505Electronic Structure, Bonding, Spectra, and Linear and Nonlinear Electric Properties of Ti@C28Skwara, Bartlomiej; Gora, Robert W.; Zalesny, Robert; Lipkowski, Pawel; Bartkowiak, Wojciech; Reis, Heribert; Papadopoulos, Manthos G.; Luis, Josep M.; Kirtman, BernardJournal of Physical Chemistry A (2011), 115 (37), 10370-10381CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The potential energy surface (PES) of Ti@C28 has been revisited, and the stationary points have been carefully characterized. In particular, the C2v symmetry structure considered previously turns out to be a transition state lying 2.3 kcal/mol above the ground state of C3v symmetry at the MP2/6-31G(d) level. A large binding energy of 181.3 kcal/mol is found at the ROMP2/6-31G(d) level. Topol. anal. of the generalized Ti@C28 d. reveals four bond paths between Ti and carbon atoms of the host. The character of all four contacts corresponds to a partially covalent closed shell interaction. UV-vis, IR, and Raman spectra are calcd. and compared with C28H4. The dipole moment and the static electronic and double harmonic vibrational (hyper)polarizabilities have been obtained. Distortion of the fullerene cage due to encapsulation leads to nonzero diagonal components of the electronic first hyperpolarizability β, and to an increase in the diagonal components of the electronic polarizability α and second hyperpolarizability γ. However, introduction of the Ti atom causes a comparable or larger redn. in most cases due to localized bonding interactions. At the double harmonic level, the av. vibrational β is much larger than its electronic counterpart, but the opposite is true for α and for the contribution to γ that has been calcd. There is also a very large anharmonic (nuclear relaxation) contribution to β which results from a shallow PES with four min. sepd. by very low barriers. Thus, the vibrational γ (and α) may, likewise, become much larger when anharmonicity is taken into account.
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254Muñoz-Castro, A.; King, R. B. Formation of spherical aromatic endohedral metallic fullerenes. Evaluation of magnetic properties of M@C28 (M = Ti, Zr, and Hf) from DFT calculations. Inorg. Chem. 2017, 56, 15251– 15258, DOI: 10.1021/acs.inorgchem.7b02611Google Scholar254https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVent77J&md5=3294db1f499724674499e6639b6c3e17Formation of Spherical Aromatic Endohedral Metallic Fullerenes. Evaluation of Magnetic Properties of M@C28 (M = Ti, Zr, and Hf) from DFT calculationsMunoz-Castro, Alvaro; King, R. BruceInorganic Chemistry (2017), 56 (24), 15251-15258CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)The small C28 cage has been shown exptl. to encapsulate titanium, zirconium, and hafnium (M), among other elements. Here, we explore computationally its magnetic response properties accounting for both global and local shielding tensors. Our results exhibit a continuous shielding region for M@C28 for an orientation-averaged applied field thereby differing from that obsd. for the hollow C28 structure. Moreover, under a specific orientation of the applied field a long-ranged shielding cone is obtained supporting the spherical arom. behavior expected by the 2(N + 1)2 Hirsch rule for M@C28, standing for its particular abundance. The comparison between the hollow and endohedral C28 fullerenes exhibits a characteristic long-range behavior at the outside region of the structure. The particular shape of the local chem. shift anisotropy tensor at a representative carbon atom exhibits inherent patterns as a consequence of the spherical arom. behavior. This shows the capabilities from NMR expts. to account for the nonarom. → arom. variation. We envisage that the current approach will be beneficial in comparative studies of arom. and electronic structure properties, to gain a deeper understanding of the geometrical and electronic structure situation in other endohedral species beyond that available from the information provided by routine NMR measurements.
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255Garg, I.; Sharma, H.; Kapila, N.; Dharamvir, K.; Jindal, V. K. Transition metal induced magnetism in smaller fullerenes (Cn for n ≤ 36). Nanoscale 2011, 3, 217– 224, DOI: 10.1039/C0NR00475HGoogle Scholar255https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXitVChtLw%253D&md5=1bb807b2775c7f93003c3e95b35ad4e4Transition metal induced magnetism in smaller fullerenes (Cn for n ≤ 36)Garg, Isha; Sharma, Hitesh; Kapila, Neha; Dharamvir, Keya; Jindal, V. K.Nanoscale (2011), 3 (1), 217-224CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The magnetic properties of 3d transition metals (TM) encapsulated inside smaller fullerenes ranging from C20 to C36 have been investigated using spin polarized d. functional theory. The TM impurities stabilize asym. at an off-center position for n ≥ 28. The total magnetic moment (MM) of TM@Cn complexes are largely contributed by TMs and a small amt. of MM of 0.12-0.50 μB is induced on the cage carbon atoms. The 3d TM atoms interact with C atoms of C20 and C28 cage ferromagnetically (FM) except for Ni@C28 which shows antiferromagnetic (AFM) interaction. The magnetic interactions change from FM to AFM in C32 cage for Ti, V, Cr and Mn. The MM gets quenched in Ni@Cn for n ≥ 32. The total MM of Mn@Cn does not show any change although the nature of magnetic interactions changes from FM to AFM at n = 32. Ti and V are the only TMs which show pos. cohesive energy in all fullerenes considered. The smallest fullerene which can encapsulate all 3d TM are Cn for n ≥ 32, consistent with available exptl. and theor. results.
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256Mulet-Gas, M.; Abella, L.; Dunk, P. W.; Rodríguez-Fortea, A.; Kroto, H. W.; Poblet, J. M. Small endohedral metallofullerenes: Exploration of the structure and growth mechanism in the Ti@C2n (2n = 26–50) family. Chem. Sci. 2015, 6, 675– 686, DOI: 10.1039/C4SC02268HGoogle Scholar256https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFekt7bN&md5=008e74db07759e8b033680a27c84e7baSmall endohedral metallofullerenes: exploration of the structure and growth mechanism in the Ti@C2n (2n = 26-50) familyMulet-Gas, Marc; Abella, Laura; Dunk, Paul W.; Rodriguez-Fortea, Antonio; Kroto, Harold W.; Poblet, Josep M.Chemical Science (2015), 6 (1), 675-686CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)The formation of the smallest fullerene, C28, was recently reported using gas phase expts. combined with high-resoln. FT-ICR mass spectrometry. An internally located group IV metal stabilizes the highly strained non-IPR C28 cage by charge transfer (IPR = isolated pentagon rule). Ti@C44 also appeared as a prominent peak in the mass spectra, and U@C28 was demonstrated to form by a bottom-up growth mechanism. We report here a computational anal. using std. DFT calcns. and Car-Parrinello MD simulations for the family of the titled compds., aiming to identify the optimal cage for each endohedral fullerene and to unravel key aspects of the intriguing growth mechanisms of fullerenes. We show that all the optimal isomers from C26 to C50 are linked by a simple C2 insertion, with the exception of a few carbon cages that require an addnl. C2 rearrangement. The ingestion of a C2 unit is always an exergonic/exothermic process that can occur through a rather simple mechanism, with the most energetically demanding step corresponding to the closure of the carbon cage. The large formation abundance obsd. in mass spectra for Ti@C28 and Ti@C44 can be explained by the special electronic properties of these cages and their higher relative stabilities with respect to C2 reactivity. We further verify that extrusion of C atoms from an already closed fullerene is much more energetically demanding than forming the fullerene by a bottom-up mechanism. Independent of the formation mechanism, the present investigations strongly support that, among all the possible isomers, the most stable, smaller non-IPR carbon cages are formed, a conclusion that is also valid for medium and large cages.
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257Muñoz-Castro, A.; Bruce King, R. Evaluation of bonding, electron affinity, and optical properties of M@C28 (M = Zr, Hf, Th, and U): Role of d-and f-orbitals in endohedral fullerenes from relativistic DFT calculations. J. Comput. Chem. 2017, 38, 44– 50, DOI: 10.1002/jcc.24518Google Scholar257https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslamtbfE&md5=7a59cf17cabbe136bdf9c6c78db1c705Bonding, electron affinity, and optical properties of M@C28 (M = Zr, Hf, Th, and U): Role of d- and f-orbitals in endohedral fullerenes from relativistic DFT calculationsMunoz-Castro, Alvaro; Bruce King, R.Journal of Computational Chemistry (2017), 38 (1), 44-50CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)The exptl. characterized endohedral metallic fullerenes involving the small C28 cage, has shown to be able to encapsulate zirconium, hafnium, and uranium atoms, among other elements. Here, we explore the formation and nature of concentric bonds from purely d- to f-block elements, given by Zr, Hf, and uranium, along a borderline metal between such blocks, thorium. We explore the interplay of d- and f-orbitals in the chem. of the early actinides, where the features of a d- or f-block metal can be mixed. Our results indicate that the bonding of Th@C28 involves contributions from both d- and f-type bonds, as characteristic of this early actinide element. Even uranium in U@C28, also exhibits a contribution from d-type bonds in addn. to its relevant f-block character. Electron affinity and optical properties were evaluated to gain more insights into the variation of these mol. properties in this small endohedral fullerene, along Zr, Hf, Th, and U. The current results, allows to unravel the role of (n - 1)d and (n - 2)f orbitals in confined elements ranging from d- to f-blocks, which can be useful to gain a deeper understanding of the bonding situation in other endohedral species.
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258Tuan, D. F.-T.; Pitzer, R. M. Electronic Structure of Hf@C28 and Its Ions. 2. CI Calculations. J. Phys. Chem. 1995, 99, 15069– 15073, DOI: 10.1021/j100041a023Google Scholar258https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXotFWnt70%253D&md5=bc69d5c478bc68dd5cefde8dec2291dfElectronic Structure of Hf@C28 and Its Ions. 2. CI CalculationsTuan, Debbie Fu-Tai; Pitzer, Russell M.Journal of Physical Chemistry (1995), 99 (41), 15069-73CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)Ab initio CI calcns. were performed on the ground and excited state of Hf@C28 and its pos. and neg. ions. Relativistic core potentials, spin-orbit operators, and symmetry-adapted functions were included in the calcns. to take into account the relativistic effects of the heavy atom and to reduce the time and effort of the computation. Double-zeta basis sets were used. Single and double excitations were included in the CI calcns. A no. of excitation energies were obtained for the Hf@C28 and its ions. The ground states of Hf@C28+, Hf@C28, and Hf@C28- in Td symmetry were found to be 2A1, 1A1, and 2E. For Hf@C28, values found were the following: ionization potential, 8.08 eV; electron affinity, 0.66 eV; and first excitation energy (to 3E state), 5.26 eV. The binding energy for Hf and C28 to form Hf@C28 was obtained as 0.71 eV. These results were compared with those from our previous SCF calcns. and with exptl. data or other theor. values where available.
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259Zhao, K.; Pitzer, R. M. Electronic structure of C28, Pa@C28, and U@C28. J. Phys. Chem. 1996, 100, 4798– 4802, DOI: 10.1021/jp9525649Google Scholar259https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xhtleisb4%253D&md5=26af4fae8c78a00dd07670d7b44aff2bElectronic Structure of C28, Pa@C28, and U@C28Zhao, Ke; Pitzer, Russell M.Journal of Physical Chemistry (1996), 100 (12), 4798-802CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)Electronic structure calcns., including relativistic core potentials and the spin-orbit interaction, have been carried out on the C28, Pa@C28, and U@C28 species. Excitation energies, spin-orbit splittings, the electron affinity, and the ionization potential are computed for C28. The ground state of C28 is described well by the Hartree-Fock wave functions, but other states are not. The computed electron affinity and ionization potential are similar to those of C60. Strong metal-cage binding is found for Pa@C28 and U@C28, similar to that in U(C8H8)2. The ground electronic states depend on the order of the lowest-energy cage π* and metal 5f orbitals, with (π*)1 and (π*)1(5f)1 found to be the ground electronic configurations for the two complexes. U@C28 is found to be diamagnetic.
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260Dai, X.; Gao, Y.; Jiang, W.; Lei, Y.; Wang, Z. U@C28: The electronic structure induced by the 32-electron principle. Phys. Chem. Chem. Phys. 2015, 17, 23308– 23311, DOI: 10.1039/C5CP04127AGoogle Scholar260https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlejs7jK&md5=3716cc48c2543128ce8f66213b68f4fcU@C28: the electronic structure induced by the 32-electron principleDai, Xing; Gao, Yang; Jiang, Wanrun; Lei, Yanyu; Wang, ZhigangPhysical Chemistry Chemical Physics (2015), 17 (36), 23308-23311CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)First principles calcns. show that the neutral U@C28 has a (cage)2 ground state with Td symmetry instead of the long believed (5f)1(cage)1 ground state with D2 symmetry. Its 34 valence electrons preferentially obey the 32-electron principle which fills all the s-, p-, d-, and f-type valence shells of the uranium atom. The remaining two valence electrons cannot break the electronic configuration and thus are located on the cage.
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261Rösch, N.; Häberlen, O. D.; Dunlap, B. I. Bonding in endohedral metal–fullerene complexes: F-orbital covalency in Ce@C28. Angew. Chem., Int. Ed. Engl. 1993, 32, 108– 110, DOI: 10.1002/anie.199301081Google ScholarThere is no corresponding record for this reference.
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262Dognon, J.-P.; Clavaguéra, C.; Pyykkö, P. A predicted organometallic series following a 32-electron principle: An@C28 (An = Th, Pa+, U2+, Pu4+). J. Am. Chem. Soc. 2009, 131, 238– 243, DOI: 10.1021/ja806811pGoogle Scholar262https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsVKlu73J&md5=572bde0b4e4d014ccbd3b12dbd825195A Predicted Organometallic Series Following a 32-Electron Principle: An@C28 (An = Th, Pa+, U2+, Pu4+)Dognon, Jean-Pierre; Clavaguera, Carine; Pyykko, PekkaJournal of the American Chemical Society (2009), 131 (1), 238-243CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The spectroscopic and thermodn. properties of the mols. M@C28 (M = Ce, Th, Pa+, U2+, Pu4+) are calcd. using d. functional theory. The systems have considerable energetic stability. It is shown that the actinide cases can be classified as "32-electron" systems, using the bonding s-, p-, d-, and f-type orbitals of the central metal. The rest of the valence MOs have purely carbon character.
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263Ryzhkov, M. V.; Ivanovskii, A. L.; Delley, B. Electronic structure of endohedral fullerenes An@C28 (An = Th–Md). Comput. Theor. Chem. 2012, 985, 46– 52, DOI: 10.1016/j.comptc.2012.01.037Google Scholar263https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjs1OlsLY%253D&md5=c889bb03c85a5696fc1225992e778d70Electronic structure of endohedral fullerenes An@C28 (An = Th - Md)Ryzhkov, Mikhail V.; Ivanovskii, Alexander L.; Delley, BernardComputational & Theoretical Chemistry (2012), 985 (), 46-52CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The geometry optimization of the neutral mols. An@C28 (An = Th - Md) was carried out using the DFT based Dmol3 method. For the calcns. of electronic structure of these complexes we used the fully relativistic discrete variational method (RDV). The systems contg. Th, Pa, U, Np and Pu have considerable energetic stability. It was found, that the 5f-orbitals contribution to chem. bonding is close to that of the 6d-states for the first half of An@C28 row. The effective charges on the atoms were calcd. using integral scheme incorporated in RDV and Hirshfeld procedure of DMol3.
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264Manna, D.; Ghanty, T. K. Prediction of a new series of thermodynamically stable actinide encapsulated fullerene systems fulfilling the 32-electron principle. J. Phys. Chem. C 2012, 116, 25630– 25641, DOI: 10.1021/jp308820zGoogle Scholar264https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1Wlt7vL&md5=e947187772237178bd300369a1cfae1bPrediction of a New Series of Thermodynamically Stable Actinide Encapsulated Fullerene Systems Fulfilling the 32-Electron PrincipleManna, Debashree; Ghanty, Tapan K.Journal of Physical Chemistry C (2012), 116 (48), 25630-25641CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)D. functional theory (DFT) within the framework of zeroth order regular approxn. has been used to predict a new class of stable clusters through encapsulation of an actinide or lanthanide atom/ion into the C26 cage. The electronic structures, bonding, stability, aromaticity and spectroscopic properties of these endohedral metallofullerenes, M@C26 (M = Pr-, Pa-, Nd, U, Pm+, Np+, Sm2+, Pu2+, Eu3+, Am3+, Gd4+, and Cm4+) have been investigated systematically using DFT and its time-dependent variant. On encapsulation of an f-block metal atom/ion with 6 valence electrons, the classical bare open shell C26 cage with D3h symmetry and ellipsoid shape is transformed to a more spherical closed shell D3h structures with high HOMO-LUMO gap (in the range of 2.44-3.99 eV for M@C26 clusters as compared to 1.62 eV for the bare C26 cage). Calcd. binding energy values imply that all of the M@C26 clusters are stable with respect to dissocn. into at. fragments. Moreover, thermodn. parameters indicate that the encapsulation process is highly favorable for all of the actinides and some of the lanthanides considered here. A higher stability and nearly spherical shape of M@C26 system is rationalized through the fulfillment of 32-electron principle corresponding to the fully occupied spdf at. shells for the encapsulated central atom, where considerable amt. of overlap between the metal and cage orbitals has been found. Thus, the calcd. structural and energetic parameters strongly suggest the possible formation of M@C26 species under appropriate exptl. conditions. Furthermore, the present work implies that the 32-electron principle might be important in designing of new materials involving lanthanides and actinides.
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265Manna, D.; Sirohiwal, A.; Ghanty, T. K. Pu@C24: A new example satisfying the 32-electron principle. J. Phys. Chem. C 2014, 118, 7211– 7221, DOI: 10.1021/jp500453vGoogle Scholar265https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjvFSjurk%253D&md5=2e1421f110f830f72f38db9483a5cb8dPu@C24: A New Example Satisfying the 32-Electron PrincipleManna, Debashree; Sirohiwal, Abhishek; Ghanty, Tapan K.Journal of Physical Chemistry C (2014), 118 (13), 7211-7221CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A transition in point group symmetry from C2 to D6d in the classical cage isomer of C24 cluster is obsd. after encapsulation of a plutonium atom within it. This encapsulation leads to highly stable Pu@C24 cluster, which is well supported by the structural, energetic, and thermodn. aspects. This study has been carried out with first five low-lying isomers of C24 fullerene, among which one is classical fullerene consisting of only five- and six-membered rings (MR) and remaining four isomers are nonclassical fullerene consisting of five and six MR along with varying no. of four MR. The structural and stability aspects are investigated extensively for the Pu@C24 cluster. For the purpose of comparison we have also considered some other lanthanides/actinides with 8 valence electrons (Cm2+, Sm, and Gd2+) and investigated the encapsulation process into different C24 isomers. The Pu@C24 cluster is the most stable one among all the metallofullerenes considered here. For Pu@C24, it has been obsd. that HOMO-LUMO gap is changed from 1.83 to 3.26 eV after encapsulation of a Pu atom into the bare classical C24 cage. The bare C24 nonclassical (C2 symmetry) cluster is the most stable one; however, after encapsulation, the classical isomer becomes the most stable with significant energy differences. The detail vibrational and electronic spectral studies have also been carried out for the classical Pu@C24 metallofullerene. High HOMO-LUMO gaps and pos. binding energy values for the Pu@C24 clusters and negatives values of reaction enthalpy and free energy corresponding to the encapsulation process indicate toward possible formation of Pu@C24 and subsequent exptl. detection. High stability of the Pu@C24 cluster can be rationalized through the fulfilment of 32 valence electron count corresponding to the fully occupied spdf shells for the central metal atom.
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266Peng, S.; Zhang, Y.; Li, X. J.; Ren, Y.; Zhang, D. X. DFT calculations on the structural stability and infrared spectroscopy of endohedral metallofullerenes. Spectrochim. Acta, Part A 2009, 74, 553– 557, DOI: 10.1016/j.saa.2009.06.051Google Scholar266https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtV2ktb3N&md5=c1ccb62c273e3ff628d54ad954227fabDFT calculations on the structural stability and infrared spectroscopy of endohedral metallofullerenesPeng, Sheng; Zhang, Yan; Li, Xiao Jun; Ren, Yan; Zhang, Deng XinSpectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy (2009), 74A (2), 553-557CODEN: SAMCAS; ISSN:1386-1425. (Elsevier B.V.)Endohedral metallofullerenes M@C24 (M = Li0/+, Na0/+, K0/+, Be0/2+, Mg0/2+ and Ca0/2+) with different spin configurations have been systematically investigated using the hybrid DFT-B3PW91 functional in conjunction with 6-31G(d) basis sets. Our theor. studies show that Li@C24, Be@C24, Be2+C@24, and Mg2+C@24 are energetically favorable. In these endohedral metallofullerenes, only the encapsulated Be and Ca atoms can donate the electrons to the cage. With exception of Be2+C@24, the energy gaps of other charged compds. are larger than that of corresponding neutral compds. We also find that some endohedral metallofullerenes have high energy gaps, but they are unlikely to show high thermodn. stability. Addnl., the vibrational frequencies and active IR intensities are also used as evidence to identify these endohedral metallofullerenes.
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267Sun, Z.; Li, X.; Tian, M.; Zhao, G.; Li, J.; Ma, B. Comparative study on metal-encapsulated TM@C24 and TM@C24H12 (TM = Ti, Zr and Hf). J. Mol. Struct.: THEOCHEM 2009, 913, 265– 269, DOI: 10.1016/j.theochem.2009.08.005Google Scholar267https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFOqtbbI&md5=6b00bffd0f9351c37e1f98a7cd744595Comparative study on metal-encapsulated TM@24 and TM@24H12 (TM=Ti, Zr and Hf)Sun, Zhicheng; Li, Xiaojun; Tian, Maosheng; Zhao, Guangjian; Li, Jincai; Ma, BingJournal of Molecular Structure: THEOCHEM (2009), 913 (1-3), 265-269CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)A comparative anal. of electronic structure and stability of endohedral metallofullerenes TM@24 and TM@24H12 (TM = Ti, Zr and Hf) is systematically performed with the aid of quantum chem. DFT-B3PW91 approach. Our calcd. results show that TM@24H12 display higher symmetry compared with TM@24, and all of endohedral metallofullerenes are in a singlet spin state. Thermodn. data reflect that endohedral metallofullerenes TM@24 are more stable than TM@24H12 and the Ti atom is energetically favorable to be encapsulated. However, these TM@24H12 have higher kinetic stability. The analyses of the vertical electron affinities (VEAs) and vertical ionization potentials (VIPs) indicate the possibilities of accepting electrons of TM@24H12 become weaker and the possibilities of denoting electrons become stronger. Addnl., natural population anal. presents that the natural charge on TM atoms dramatically increases along with increasing at. no., and the 5d orbitals of Zr atom and 6d orbitals of Hf atom are significantly involved in their chem. bonding.
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268Zhang, Y.; Peng, S.; Li, X. J.; Zhang, D. X. Structural stability, electronegativity and electronic property of endohedral TM@C24 and exohedral TMC24 (TM = Sc, Y and La) metallofullerene complexes: Density-functional theory investigations. J. Mol. Struct.: THEOCHEM 2010, 947, 16– 21, DOI: 10.1016/j.theochem.2010.01.030Google Scholar268https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjtFKlsbs%253D&md5=0e31335dbb1ca1b141753ac13d0337eeStructural stability, electronegativity and electronic property of endohedral TM@C24 and exohedral TMC24 (TM=Sc, Y and La) metallofullerene complexes: Density-functional theory investigationsZhang, Yan; Peng, Sheng; Li, Xiao Jun; Zhang, Deng XinJournal of Molecular Structure: THEOCHEM (2010), 947 (1-3), 16-21CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)The structural stability, electronegativity and electronic property of endohedral TM@C24 and exohedral TM-C24 (TM = Sc, Y and La) complexes have been systematically investigated using the hybrid DFT-(U)B3PW91 functional. The calcd. results show that the endohedral complexes do not undergo any major deformation in the structures, and the Sc atom is energetically favorable to be encapsulated into the center of the cage. But in the Y and La cases the exohedral structure is more stable than the endohedral structure. The frontier orbital analyses indicate that the exohedral TM-C24 complexes have the high kinetic stabilities, which are consistent with their thermodn. stabilities. Addnl., natural population analyses also tell us that the natural charges on TM atoms are obviously increased with the increasing at. radii except for the endohedral La@C24. In the La@C24, the La atom acts as an electron acceptor with the neg. charges. And its 4f orbitals are significantly involved in the formation of the chem. bonding.
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269Wu, J.; Sun, Z.; Li, X.; Chen, L.; Tian, M. Molecular geometries, electronic properties, and vibrational spectroscopic studies of endohedral metallofullerenes TM@C24 and TM@C24H12 (TM = Cr, Mo, and W). Struct. Chem. 2010, 21, 673– 680, DOI: 10.1007/s11224-010-9597-7Google Scholar269https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXosVWmtbg%253D&md5=f9158586176e4c1dcaa93af00f26494eMolecular geometries, electronic properties, and vibrational spectroscopic studies of endohedral metallofullerenes TM@C24 and TM@C24H12 (TM = Cr, Mo, and W)Wu, Julong; Sun, Zhicheng; Li, Xiaojun; Chen, Liang; Tian, MaoshengStructural Chemistry (2010), 21 (4), 673-680CODEN: STCHES; ISSN:1040-0400. (Springer)Mol. geometries, electronic properties, and vibrational spectroscopies of TM@CV24 and TM@C 24H12 (TM = Cr, Mo, and W) in their different spin configurations have been systematically investigated with the hybrid DFT-(U)B3PW91 functional. The results show that the TM atoms bind over the pentagon ring inside C24 cage, and they move gradually toward the center of C24 cage along with the increasing at. radii. The most stable Mo@C24H12 and W@C24H12 are in their spin-triplet states. The analyses of dissocn. energy and energy gap reveal that TM@C24 (TM = Cr, Mo, and W) and Cr@C24H12 are not only thermodynamically stable, but also considerably stable kinetically. Meanwhile, natural population analyses tell us that the two cages act as electron acceptors, and the transferred charge from the W atom to C24 cage is the largest in the endohedral metallofullerenes. Addnl., the vibrational frequencies and active IR intensities may be used as evidence to characterize these unknown species.
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270Yue, Y.; Li, X. J. Density functional investigations of endohedral metallofullerenes TM@C24 (TM = Mn, Fe, Co, Ni, Cu, and Zn. Int. J. Quantum Chem. 2011, 111, 96– 102, DOI: 10.1002/qua.22393Google Scholar270https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlaqt7%252FP&md5=2a8aa30e38f91a1e788adcb3e39ce90bDensity functional investigations of endohedral metallofullerenes TM@C24 (TM = Mn, Fe, Co, Ni, Cu, and Zn)Yue, Yun; Li, Xiao-JunInternational Journal of Quantum Chemistry (2011), 111 (1), 96-102CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)The theor. investigations on TM@C24 (TM = Mn, Fe, Co, Ni, Cu, and Zn) with different spin configurations have been performed by using the hybrid DFT-B3PW91 functional in conjunction with 6-31G(d) basis sets. The results show that the ground states of Fe@C24 and Ni@C24 are their spin triplet states, whereas the ground state of Co@C24 is spin quartet state. Moreover, three Fe@C24 isomers are favorable in energy. The HOMO and LUMO of Zn@C24 indicates that there is no hybridization between Zn AOs and the C24 cage orbitals. Natural population anal. shows that the charges always transfer from the TM atoms to the C24 cage. In going from isolated TM atom to TM@C24, the occupation of the 4s orbital is strongly reduced. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011.
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271Erkoç, Ş. Metal atom endohedrally doped C20 cage structure: (X@C20; X = Ni, Fe, Co. Int. J. Mod. Phys. C 2005, 16, 1553– 1560, DOI: 10.1142/S0129183105008138Google Scholar271https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFOrsb3I&md5=41ee6e9fd56c10ac28f02ad7212c50f8Metal atom endohedrally doped C20 cage structure: (X@C20; X = Ni, Fe, Co)Erkoc, SakirInternational Journal of Modern Physics C (2005), 16 (10), 1553-1560CODEN: IJMPCM; ISSN:0129-1831. (World Scientific Publishing Co. Pte. Ltd.)The C20 cage structure (X@C20; X = Fe, Co, Ni) endohedrally doped with a metal atom has been investigated theor. by performing mol.-mechanics optimizations, and semi-empirical PM3 level and d. functional theory B3LYP/6-31G* level calcns. within UHF formalism. Calcns. have been performed with different spin configurations for the neutral systems.
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272Poklonski, N. A.; Kislyakov, E. F.; Vyrko, S. A.; Hieu, N. N.; Bubel, O. N.; Siahlo, A. I.; Lebedeva, I. V.; Knizhnik, A. A.; Popov, A. M.; Lozovik, Y. E. Magnetically operated nanorelay based on two single-walled carbon nanotubes filled with endofullerenes Fe@C20. J. Nanophotonics 2010, 4, 041675, DOI: 10.1117/1.3417104Google ScholarThere is no corresponding record for this reference.
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273Samah, M.; Boughiden, B. Structures, electronic and magnetic properties of C20 fullerenes doped transition metal atoms M@C20 (M = Fe, Co, Ti, V). Int. J. Mod. Phys. C 2010, 21, 1469– 1477, DOI: 10.1142/S0129183110015968Google Scholar273https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhs1SrtbjP&md5=19d69cfd5de68ee9f0e62ecc6c3d028cStructures, electronic and magnetic properties of C20 fullerenes doped transition metal atoms M@20 (M = Fe, Co, Ti, V)Samah, M.; Boughiden, B.International Journal of Modern Physics C: Computational Physics, Physical Computation (2010), 21 (12), 1469-1477CODEN: IJMPCM; ISSN:0129-1831. (World Scientific Publishing Co. Pte. Ltd.)Structures, binding energies, magnetic and electronic properties endohedrally doped C20 fullerenes by metallic atoms (Fe, Co, Ti and V) have been obtained by pseudopotential d. functional theory. All M@20, except Co@20, are more stable than the undoped C20 cage. The magnetic moment values are 1 and 2μB. These values and semiconductor behavior give to these compds. interesting feature in several technol. applications. Titanium doped C20 has a same magnetic moment than the isolated Ti atom. Hybridization process in the Co doped C20 fullerene is most strong than in other doped cages. Elec. and magnetic dipoles calcd. in the iron doped C20 are very strong compared with other clusters.
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274Baei, M. T.; Soltani, A.; Torabi, P.; Hosseini, F. Formation and electronic structure of C20 fullerene transition metal clusters. Monatsh. Chem. 2014, 145, 1401– 1405, DOI: 10.1007/s00706-014-1218-5Google Scholar274https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXovVWrtLc%253D&md5=eebd3b176194b37d8efd2a95890191cbFormation and electronic structure of C20 fullerene transition metal clustersBaei, Mohammad T.; Soltani, Alireza; Torabi, Parviz; Hosseini, FarzanehMonatshefte fuer Chemie (2014), 145 (9), 1401-1405CODEN: MOCMB7; ISSN:0026-9247. (Springer-Verlag GmbH)The structure and electronic properties of TM@C20 (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) complexes were investigated. The study revealed that the doping processes of Sc, Ti, V, Cr, Mn, and Fe atoms at the center of C20 fullerene are exothermic and those of Co, Ni, Cu, and Zn atoms are endothermic. In addn., the endohedral complexation with Sc, Ti, V, Cr, Mn, and Fe atoms significantly influence the electronic properties of the C20 clusters. The calcd. vibrational frequencies for the Ti, V, and Mn complexes were pos., confirming the complexes are stable and can stabilize the unstable C20 fullerene with Ih symmetry. The present results reveal details for the synthesis and structuring of C20 fullerene doped with Ti, V, and Mn and serves for the further developments of C20-based particles to generate new hybrid compds.
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275An, Y.-P.; Yang, C.-L.; Wang, M.-S.; Ma, X.-G.; Wang, D.-H. Ab initio investigations of the charge transport properties of endohedral M@C20 (M = Na and K) metallofullerenes. Chin. Phys. B 2010, 19, 113402, DOI: 10.1088/1674-1056/19/11/113402Google Scholar275https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisVCgt74%253D&md5=c26f5095f8a72302976df87f0990fa77Ab initio investigations of the charge transport properties of endohedral M@C20 (M = Na and K) metallofullerenesAn, Yi-Peng; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Wang, De-HuaChinese Physics B (2010), 19 (11), 113402/1-113402/6CODEN: CPBHAJ; ISSN:1674-1056. (Chinese Physical Society)Using d. functional theory and quantum transport calcns. based on nonequilibrium Green's function formalism, we investigate the charge transport properties of endohedral M@C20(M = Na and K) metallofullerenes. Our results show that the conductance of C20 fullerene can be obviously improved by insertion of alkali atom at its center. Both linear and nonlinear sections are found on the I-V curves of the Au-M@C20-Au two-probe systems. The novel neg. differential resistance behavior is also obsd. in Na@C20 mol. but not in K@C20.
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276An, Y.-P.; Yang, C.-L.; Wang, M.-S.; Ma, X.-G.; Wang, D.-H. Geometrical and electronic properties of the clusters of C20 cage doped with alkali metal atoms. J. Cluster Sci. 2011, 22, 31– 39, DOI: 10.1007/s10876-011-0354-xGoogle Scholar276https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjtFamtrs%253D&md5=b941e4f1b23f54622026633334eae753Geometrical and Electronic Properties of the Clusters of C20 Cage Doped with Alkali Metal AtomsAn, Yi-Peng; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Wang, De-HuaJournal of Cluster Science (2011), 22 (1), 31-39CODEN: JCSCEB; ISSN:1040-7278. (Springer)Using first-principles d.-functional theory based on the generalized gradient approxn., we have investigated the geometrical and electronic properties of the pure C20 cage with D3d symmetry and M@20(M = Li, Na, K, Rb, Cs) clusters with Ih symmetry. It is found that the interstitial M@20 clusters are energetically stable and have strong total magnetic moments. The stability is analyzed through charge distributions on the atoms and the magnetism is explained through the degeneracy and fractional occupation of the MOs.
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277Wu, J.; Sun, Z.; Li, X.; Ma, B.; Tian, M.; Li, S. Theoretical study on the smallest endohedral metallofullerenes: TM@C20 (TM = Ce and Gd). Int. J. Quantum Chem. 2010, 111, 3786– 3792, DOI: 10.1002/qua.22908Google ScholarThere is no corresponding record for this reference.
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278Manna, D.; Ghanty, T. K. Theoretical prediction of icosahedral U@C20 and analogous systems with high HOMO–LUMO gap. J. Phys. Chem. C 2012, 116, 16716– 16725, DOI: 10.1021/jp302138pGoogle Scholar278https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XptF2nsLs%253D&md5=656141002733654e9a1f06aa0c6dd9ddTheoretical Prediction of Icosahedral U@C20 and Analogous Systems with High HOMO-LUMO GapManna, Debashree; Ghanty, Tapan K.Journal of Physical Chemistry C (2012), 116 (31), 16716-16725CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The electronic structures, bonding, stability, aromaticity, and spectroscopic properties of the endohedral metallofullerenes, M@C20 (M = Pr-, Pa-, Nd, U, Pm+, Np+, Sm2+, Pu2+, Eu3+, Am3+, Gd4+, and Cm4+), were investigated in a unified and systematic way using relativistic d. functional theory (DFT) within the framework of zeroth-order regular approxn. The bare C20 cage with D3d point group transforms to highly sym. Ih structure through encapsulation of an f-block metal atom/ion with 6 valence electrons. The calcd. values of HOMO-LUMO gap lie in the range of 2.5-4.9 eV (8.8-11.5 eV) at the B3LYP (HF) level. The stability of these metal encapsulated clusters can be attributed to the fulfillment of 26 valence electrons criteria corresponding to the fully occupied 2s2p1d at. shells, where strong participation of the central metal atom orbitals in the ag, t1u, gu, and hg valence MOs have been obsd.
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279Meng, F.; Zhou, Z.; Zhang, P.; Jiang, M.; Xu, X.; Wang, Y.; Gou, J.; Hui, D.; Die, D. Encapsulation of an f-block metal atom/ion to enhance the stability of C20 with the Ih symmetry. Phys. Chem. Chem. Phys. 2015, 17, 4328– 4336, DOI: 10.1039/C4CP03159HGoogle Scholar279https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvVWqug%253D%253D&md5=9c1fdc2da4a59129e2661b81d118f86aEncapsulation of an f-block metal atom/ion to enhance the stability of C20 with the Ih symmetryMeng, Fanchen; Zhou, Zuowan; Zhang, Pinliang; Jiang, Man; Xu, Xiaoling; Wang, Yong; Gou, Jihua; Hui, David; Die, DongPhysical Chemistry Chemical Physics (2015), 17 (6), 4328-4336CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Based on the d. functional theory, the geometric and electronic structures, chem. stability, and bonding properties of the endohedral metallofullerenes, M@C20 (M = Eu3-, Am3-, Gd2-, Cm2-, Tb-, Bk-, Dy, Cf, Ho+, Es+, Er2+, Fm2+, Tm3+, Md3+, Yb4+, No4+, Lu5+, and Lr5+), were investigated. Through encapsulation of an f-block metal atom/ion with 12 valence electrons, the bare C20 cage with the D2h point group could be stabilized to a highly sym. Ih structure. The calcd. values of HOMO-LUMO energy gaps using the B3lYP and BHHLYP functionals ranged from 2.22 to 5.39 eV and from 3.89 to 7.95 eV, resp. The stability of these metal-encapsulated clusters can be attributed to the 32-electron rule, where the central metal atom's orbitals strongly participated in the t2u, gu, t1u, hg, and ag valence MOs.
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280Muñoz-Castro, A.; King, R. B. On the formation of smaller p-block endohedral fullerenes: Bonding analysis in the E@C20 (E = Si, Ge, Sn, Pb) series from relativistic DFT calculations. J. Comput. Chem. 2017, 38, 1661– 1667, DOI: 10.1002/jcc.24809Google Scholar280https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXmsFantrY%253D&md5=067a7461acf5147cc3607513f6f3ca88On the formation of smaller p-block endohedral fullerenes: Bonding analysis in the E@C20 (E = Si, Ge, Sn, Pb) series from relativistic DFT calculationsMunoz-Castro, Alvaro; King, R. BruceJournal of Computational Chemistry (2017), 38 (19), 1661-1667CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)Exptl. characterized endohedral metallofullerenes are of current interest in expanding the range of viable fullerenic structures and their applications. Smaller metallofullerenes, such as M@C28, show that several d- and f-block elements can be efficiently confined in relatively small carbon cages. This article explores the potential capabilities of the smallest fullerene cage, i.e., C20, to encapsulate p-block elements from group 14, i.e., E = Si, Ge, Sn, and Pb. Our interest relates to the bonding features and optical properties related to E@C20. The results indicate both s- and p-type concentric bonds, in contrast to the well explored endohedral structures encapsulating f-block elements. Our results suggest the E@C20 series to be a new family of viable endohedral fullerenes. In addn., optical and vibrational spectroscopic properties and electron affinity were modeled to gain further information useful for characterization. Characteristic optical patterns were studied predicting a distinctive first peak located between 400 and 250 nm, which is red-shifted going to the heavier encapsulated Group 14 atoms. Electron affinity properties expose different patterns useful to differentiate the hollow C20 fullerene to the proposed p-block endohedral counterparts. © 2017 Wiley Periodicals, Inc.
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281Gonzalez, M.; Lujan, S.; Beran, K. A. Investigation into the molecular structure, electronic properties, and energetic stability of endohedral (TM@C20) and exohedral (TM-C20) metallofullerene derivatives of C20: TM = Group 11 and 12 transition metal atoms/ions. Comput. Theor. Chem. 2017, 1119, 32– 44, DOI: 10.1016/j.comptc.2017.09.013Google Scholar281https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFOltbbK&md5=11c23b5ffeb42a99040017b813a9fa5eInvestigation into the molecular structure, electronic properties, and energetic stability of endohedral (TM@C20) and exohedral (TM-C20) metallofullerene derivatives of C20: TM = Group 11 and 12 transition metal atoms/ionsGonzalez, Mariela; Lujan, Samantha; Beran, Kyle A.Computational & Theoretical Chemistry (2017), 1119 (), 32-44CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)D.-functional theory at the B3LYP/LanL2DZ level has been employed to probe the structure and electronic properties of the D2h-sym. C20 fullerene. The energetic stability of C20 is assessed as transition metals (TM) from Groups 11 and 12 are inserted at either endohedral (TM@C20) or exohedral (TM-C20) sites. The anal. encompasses various ionizations and spin states for each metal. The lowest-energy exohedral derivs. in Group 11 all favor the low spin-state, whereas the neutral Group 12 complexes favor the high spin-state. The energetic stability of the exohedral, as measured by the dissocn. energy, increases as the charge increases for a given metal. Significantly more interaction occurs between the TM and the C20 cage in the endohedral derivs. as is evidenced by elec. charge being transferred to the carbon cage from both the ns and (n-1)d AOs of the TM. There was not an obsd. preference of spin-state for the endohedrals since in many cases the relative energy difference between comparable spin-states ranged between 0.00 eV and 1.10 eV. Of the endohedrals only Zn@C2+20 and Cu@C2+20 yielded total energies that were less and therefore more stable than the isolated C20 and TM entities.
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282Szwacki, N. G.; Sadrzadeh, A.; Yakobson, B. I. B80 fullerene: An ab initio prediction of geometry, stability, and electronic structure. Phys. Rev. Lett. 2007, 98, 166804, DOI: 10.1103/PhysRevLett.98.166804Google ScholarThere is no corresponding record for this reference.
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283Szwacki, N. G.; Sadrzadeh, A.; Yakobson, B. I. Erratum: B80 Fullerene: An ab initio prediction of geometry, stability, and electronic structure [Phys. Rev. Lett. 98, 166804 (2007)]. Phys. Rev. Lett. 2008, 100, 159901, DOI: 10.1103/PhysRevLett.100.159901Google ScholarThere is no corresponding record for this reference.
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284Zhao, J.; Wang, L.; Li, F.; Chen, Z. B80 and other medium-sized boron clusters: Core–shell structures, not hollow cages. J. Phys. Chem. A 2010, 114, 9969– 9972, DOI: 10.1021/jp1018873Google Scholar284https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXpvFSntbo%253D&md5=92ced38cd00f048b6b723b692db50963B80 and Other Medium-Sized Boron Clusters: Core-Shell Structures, Not Hollow CagesZhao, Jijun; Wang, Lu; Li, Fengyu; Chen, ZhongfangJournal of Physical Chemistry A (2010), 114 (37), 9969-9972CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Unbiased search on the potential energy surface of medium-sized boron clusters, with B80, B74, and B68 as representatives, was carried out using simulated annealing incorporated with first-principles DFT-GGA-PBE mol. dynamics. These boron clusters thermodynamically prefer the B12-centered core-shell structures, which resemble the fragment of bulk boron solids. Though these core-shell clusters lack a descriptive symmetry and may not be the true global min.; the core-shell B80 is about 25 meV/atom lower in energy than the widely assumed highly stable "magic" B80 fullerene. The electronic states and photoelectron spectra of these clusters are closely correlated to the structural motif, which may be helpful for detecting the cluster configurations in expts.
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285De, S.; Willand, A.; Amsler, M.; Pochet, P.; Genovese, L.; Goedecker, S. Energy landscape of fullerene materials: A comparison of boron to boron nitride and carbon. Phys. Rev. Lett. 2011, 106, 225502, DOI: 10.1103/PhysRevLett.106.225502Google Scholar285https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXotVCgs70%253D&md5=5ac23fb09e9225c5a4bc9b8b784a292cEnergy Landscape of Fullerene Materials: A Comparison of Boron to Boron Nitride and CarbonDe, Sandip; Willand, Alexander; Amsler, Maximilian; Pochet, Pascal; Genovese, Luigi; Goedecker, StefanPhysical Review Letters (2011), 106 (22), 225502/1-225502/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Using the min. hopping global geometry optimization method on the d. functional potential energy surface we show that the energy landscape of boron clusters is glasslike. Larger boron clusters have many structures which are lower in energy than the cages. This is in contrast to carbon and boron nitride systems which can be clearly identified as structure seekers. The differences in the potential energy landscape explain why carbon and boron nitride systems are found in nature whereas pure boron fullerenes have not been found. We thus present a methodol. which can make predictions on the feasibility of the synthesis of new nanostructures.
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286Rahane, A. B.; Kumar, V. B84: A quasi-planar boron cluster stabilized with hexagonal holes. Nanoscale 2015, 7, 4055– 4062, DOI: 10.1039/C4NR06026AGoogle Scholar286https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVGjtbs%253D&md5=1f277aebc5053b4f48cfd32f8ae78170B84: a quasi-planar boron cluster stabilized with hexagonal holesRahane, Amol B.; Kumar, VijayNanoscale (2015), 7 (9), 4055-4062CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)We report the finding of a bowl-shaped quasi-planar structure of a B84 cluster with four hexagonal holes and a three-chain ring all around the edges using ab initio calcns. A large no. of other isomers including those explored earlier such as an empty cage, a filled cage, and a disordered structure, have been found to lie in a significantly higher energy band. A tubular structure, however, is only about 0.45 eV higher in energy. Calcns. of the IR and Raman spectra show that the quasi-planar structure is dynamically stable. These results suggest that quasi-planar structures may be among the low energy structures for larger clusters as well. Accordingly we have calcd. the optimal quasi-planar structures stabilized with 2, 3, 5, 6, and 7 hexagonal holes also. The stability of quasi-planar structures is discussed in terms of multi-center two-electron bonding and it is shown that with increasing size their binding energy tends to approach the value for an α-boron sheet.
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287Xu, S.-G.; Zhao, Y.-J.; Yang, X.-B.; Xu, H. A practical criterion for screening stable boron nanostructures. J. Phys. Chem. C 2017, 121, 11950– 11955, DOI: 10.1021/acs.jpcc.7b03359Google Scholar287https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXnvFCmt7k%253D&md5=6b550d34d8f600a23bfa8898b166a5ddA Practical Criterion for Screening Stable Boron NanostructuresXu, Shao-Gang; Zhao, Yu-Jun; Yang, Xiao-Bao; Xu, HuJournal of Physical Chemistry C (2017), 121 (21), 11950-11955CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Due to the electron deficiency, boron clusters evolve strikingly with the increasing size as confirmed by experimentalists and theorists. However, it is still a challenge to propose a model potential to describe the stabilities of boron. On the basis of the 2c-2e and 3c-2e bond models, we have found the constraints for stable boron clusters, which can be used for detg. the vacancy concn. and screening the candidates. Among numerous tubular structures and quasi-planar structures, we have verified that the stable clusters with lower formation energies bounded by the constraints, indicating the competition of tubular and planar structures. Notably, we have found a tubular cluster of B76 which is more stable than the B80 cage. We show that the vacancies, as well as the edge, are necessary for the 2c-2e bonds, which will stabilize the boron nanostructures. Therefore, the quasi-planar and tubular boron nanostructures could be as stable as the cages, which have no edge atoms. Our finding has shed light on understanding the complicated electron distributions of boron clusters and enhancing the efficiency of searching stable B nanostructures.
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288Pochet, P.; Genovese, L.; De, S.; Goedecker, S.; Caliste, D.; Ghasemi, S. A.; Bao, K.; Deutsch, T. Low-energy boron fullerenes: Role of disorder and potential synthesis pathways. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 83, 081403, DOI: 10.1103/PhysRevB.83.081403Google Scholar288https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXis1Oqsr4%253D&md5=daaa38cac0aec85cc9809d95797a4256Low-energy boron fullerenes: Role of disorder and potential synthesis pathwaysPochet, Pascal; Genovese, Luigi; De, Sandip; Goedecker, Stefan; Caliste, Damien; Ghasemi, S. Alireza; Bao, Kuo; Deutsch, ThierryPhysical Review B: Condensed Matter and Materials Physics (2011), 83 (8), 081403/1-081403/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We show by means of first-principles BigDFT-code calcns. that in boron nanostructures a large variety of two-dimensional structures can be obtained, all with similar energetic properties. Some of these new structures are more stable than both the B80 fullerenes initially proposed by Szwacki and boron nanotubes. At variance from other systems like carbon, disordered configurations are energetically comparable with ordered ones. Cage-like structures that are not ordered are thus comparable in energy to the more ordered original B80 fullerene. A comparison with other more disordered structures like bulk-like boron clusters is also presented. We found that in the presence of other seed structures (like Sc3 or Sc3N), some endohedral cage-like structures are energetically preferred over bulk-like clusters. This result opens a new pathway for the synthesis of the B80 fullerene as an endohedral fullerene as was done in the case of the C80 fullerene.
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289Li, J. L.; Yang, G. W. Iron endohedral-doped boron fullerene: A potential single molecular device with tunable electronic and magnetic properties. J. Phys. Chem. C 2009, 113, 18292– 18295, DOI: 10.1021/jp9064592Google Scholar289https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFyqsrnI&md5=ca78ad784bd1747cbb3e3fa9994fd859Iron Endohedral-Doped Boron Fullerene: A Potential Single Molecular Device with Tunable Electronic and Magnetic PropertiesLi, J. L.; Yang, G. W.Journal of Physical Chemistry C (2009), 113 (42), 18292-18295CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The authors have theor. performed that Fe endohedral-doped boron fullerene (B80) is a potential single mol. device with tunable electronic and magnetic properties. Both the energy gap and magnetic moment of the Fe endohedral-doped B80 can be greatly tuned, simultaneously by changing the position of the Fe atom inside the hollow cage of B80. In comparison with that of the Fe endohedral-doped B80 with Fe atom located at center-at, the energy gap decreases half and the magnetic moment decreases zero for the case of the Fe endohedral-doped B80 with the Fe atom located at hexagon-in in the hollow cage. These fascinating findings imply that the Fe endohedral-doped B80 with tunable electronic and magnetic properties can be expected to be applicable as a single mol. device.
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290Li, J. L.; Yang, G. W. Tuning electronic and magnetic properties of endohedral Co@B80 and exohedral Co-B80 metallofullerenes by positioning Co atom. J. Appl. Phys. 2010, 107, 113702, DOI: 10.1063/1.3431522Google Scholar290https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvVajtb4%253D&md5=cf9d13e3683aa56c017ef0de32e5732eTuning electronic and magnetic properties of endohedral Co@B80 and exohedral Co-B80 metallofullerenes by positioning Co atomLi, J. L.; Yang, G. W.Journal of Applied Physics (2010), 107 (11), 113702/1-113702/5CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)We have performed a systematical study of the structural configurations, electronic and magnetic properties of the single Co-doped endohedral Co@B80 and exohedral Co-B80 metallofullerene complexes using spin-polarized d. functional calcns. Our calcns. revealed that there are 4 stable configurations of the Co-doped metallofullerenes depending on different positions of the doping Co atoms as follows. In the case of the exohedral Co-B80 metallofullerene complexes, Co atom energetically prefers standing near the centers of pentagon (pentagon-out) and hexagon (hexagon-out) on the surface of B80. In the case of the endohedral Co@B80 metallofullerene complexes, the encapsulated Co atom energetically prefers standing near the centers of pentagon (pentagon-in) and hexagon (hexagon-in) on the inner surface of the hollow cage of B80. Electronically, the energy gaps of the hexagon-near adsorbed metallofullerenes were greatly modified compared with that of B80. At the same time, the magnetic moments of both of the exohedral Co-B80 metallofullerenes are 1/3 of that of the isolated Co atom. The tunable electronic and magnetic properties of the Co-doped B80 metallofullerenes clearly showed that this new type of metallofullerenes may be a promising candidate for mol. devices, esp. single mol. spin electronic devices. (c) 2010 American Institute of Physics.
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291Li, J. L.; Yang, G. W. Ni@B80: A single molecular magnetic switch. Appl. Phys. Lett. 2009, 95, 133115, DOI: 10.1063/1.3242362Google Scholar291https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1Wmt7jN&md5=9aa7d8e72409ea6f3530836f6b0c0c1cNi@B80: A single molecular magnetic switchLi, J. L.; Yang, G. W.Applied Physics Letters (2009), 95 (13), 133115/1-133115/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The authors theor. performed that the magnetic moment of Ni-encapsulated B80(Ni@B80) can be greatly tuned by changing the position of Ni atom inside the hollow cage of B80. There are three stable configurations of Ni@B80 with Ni atom located at center, pentagon, and hexagonal-in, resp. Compared with that of Ni @ B80 with Ni atom located at center, all the magnetic moments of Ni @ B80's with Ni atom located at pentagon and hexagon-in in the hollow cage of B80 are zero. These fascinating findings imply that Ni @ B80 may be a promising candidate for single mol. magnetic switch. (c) 2009 American Institute of Physics.
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292Li, C.; Liu, J.; Lefkidis, G.; Hübner, W. Reversible ultrafast spin switching on Ni@B80 endohedral fullerene. Phys. Chem. Chem. Phys. 2017, 19, 673– 680, DOI: 10.1039/C6CP06492BGoogle Scholar292https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFCjur%252FF&md5=b9bc0238a74d098b9816ce02c9a9f779Reversible ultrafast spin switching on Ni@B80 endohedral fullereneLi, Chun; Liu, Jing; Lefkidis, Georgios; Hubner, WolfgangPhysical Chemistry Chemical Physics (2017), 19 (1), 673-680CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We present the configurations and stability of the endohedral metallofullerene Ni@B80 by using strict and elaborate geometric modeling. The ultrafast spin switching on Ni@B80 is explored through ab initio calcns. It is shown that there are three stable configurations of Ni@B80 endohedral fullerene with the encaged Ni atom located at different sites. The ultrafast spin switching on Ni@B80via Λ processes can be achieved through at least eight paths with different laser pulses. Among them, the fastest one can be accomplished within 100 fs. In particular, it is found that all the spin-switching processes achieved on the H-type structure are reversible with the use of the same or different laser pulses. Considering the obtained high fidelities of these switching processes, the present theor. prediction could lead to promising applications in the design of integrated spin-logic devices through appropriate spin manipulation in endohedral boron fullerenes.
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293Mahdavifar, Z.; Poulad, M. Theoretical prediction of ozone sensing using pristine and endohedral metalloboron B80 fullerenes. Sens. Actuators, B 2014, 205, 26– 38, DOI: 10.1016/j.snb.2014.08.059Google Scholar293https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVOhsbnJ&md5=19066847ae611e03e7983605341be0e3Theoretical prediction of ozone sensing using pristine and endohedral metalloboron B80 fullerenesMahdavifar, Zabiollah; Poulad, MarziyehSensors and Actuators, B: Chemical (2014), 205 (), 26-38CODEN: SABCEB; ISSN:0925-4005. (Elsevier B.V.)The adsorption of ozone on B80 and endohedral Be@B80 fullerenes is ascertained with d. functional theory. The potential energy curve of ozone adsorption on pristine and endohedral B80 fullerenes is investigated. Obtained data indicate that the behavior of O3 adsorption on investigated fullerenes can be better described by Cor.-Morse potential equation. On the basis of results, the ozone can be adsorbed onto the outer surface of pristine B80 mol. with adsorption energy of -327.34 kJ mol-1. The tangible adsorption energy of O3 onto the B80 and relatively bond length of B-O (∼1.45 Å) in B80/O3 system imply that this structure is of highly stability. Compared the calcd. adsorption energy of O3 adsorbed on Be@B80 system (-498.87 kJ mol-1) with pristine B80, indicate that when the metal atom encapsulated into the B80 fullerene, the adsorption of ozone on Be@B80 is more favorable than pristine B80. Also, the presence of Be metal atom can be improved the oxidn. process of B80 fullerene. During the oxidn. process of Be@B80 fullerene using ozone, the Be metal atom translated from the center to wall of the B80 and strongly bonded to the boron atoms of inner walls. Based on our results, it seems that ozone tends to be chemisorbed onto the B80 and Be@B80 fullerenes with appreciable adsorption energy, whereas the Be@B80 fullerene is more favorable than pristine B80. Furthermore, due to the disappeared some energy level near the LUMO and decreased the Eg, the elec. conductance of the B80/O3 and Be@B80/O3 systems are increased. In conclusion, pristine B80 and Be@B80 fullerenes can be converted the presence of O3 mol. directly to an elec. signal, and therefore, it can be potentially used as ozone sensor.
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294Jin, P.; Hao, C.; Gao, Z.; Zhang, S. B.; Chen, Z. Endohedral metalloborofullerenes La2@B80 and Sc3N@B80: A density functional theory prediction. J. Phys. Chem. A 2009, 113, 11613– 11618, DOI: 10.1021/jp9019848Google Scholar294https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXos1Cgsb4%253D&md5=42c9a4fbf44ed9526b6404474a1e9dd8Endohedral Metalloborofullerenes La2@B80 and Sc3N@B80: A Density Functional Theory PredictionJin, Peng; Hao, Ce; Gao, Zhanxian; Zhang, Shengbai B.; Chen, ZhongfangJournal of Physical Chemistry A (2009), 113 (43), 11613-11618CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The geometries, electronic and spectroscopic properties of two representative endohedral derivs. of B80 fullerene, namely, La2@B80 and Sc3N@B80, and the possibility for their prodn. were investigated by means of d. functional computations. The very favorable binding energies suggest a considerable possibility to exptl. realize these novel endohedral metalloborofullerenes. IR absorption spectra and 11B NMR spectra were also computed to assist future exptl. characterization.
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295Liu, C.; Yang, L.; Jin, P.; Hou, Q.; Li, L. Computational prediction of endohedral dimetalloborofullerenes M2@B80 (M = Sc, Y). Chem. Phys. Lett. 2017, 676, 89– 94, DOI: 10.1016/j.cplett.2017.03.054Google Scholar295https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXltl2ksbY%253D&md5=01a20630de792572efc461d8baacd14cComputational prediction of endohedral dimetalloborofullerenes M2@B80 (M = Sc, Y)Liu, Chang; Yang, Le; Jin, Peng; Hou, Qinghua; Li, LanlanChemical Physics Letters (2017), 676 (), 89-94CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometries and electronic properties of two new endohedral metalloborofullerenes M2@B80 (M = Sc, Y) were investigated by means of d. functional theory computations. The two complexes feature favorable binding energies, suggesting a considerable possibility to be achieved. Sc2@B80 exhibits a flexible metal motion with tunable magnetic moment and may be a promising single mol. magnetic switch. The metal-metal and metal-cage bonding natures were thoroughly disclosed by using various theor. approaches. Their excellent stabilities were confirmed by the Born-Oppenheimer mol. dynamics simulations at different temps. Finally, IR spectra and 11B NMR spectra were simulated to assist exptl. characterization.
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296Jin, P.; Liu, C.; Hou, Q.; Li, L.; Tang, C.; Chen, Z. Scandium carbides/cyanides in the boron cage: Computational prediction of X@B80 (X = Sc2C2, Sc3C2, Sc3CN and Sc3C2CN). Phys. Chem. Chem. Phys. 2016, 18, 21398– 21411, DOI: 10.1039/C6CP02884EGoogle Scholar296https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVyhsLjE&md5=6c330946e327f2a41285db221bea335dScandium carbides/cyanides in the boron cage: computational prediction of X@B80 (X = Sc2C2, Sc3C2, Sc3CN and Sc3C2CN)Jin, Peng; Liu, Chang; Hou, Qinghua; Li, Lanlan; Tang, Chengchun; Chen, ZhongfangPhysical Chemistry Chemical Physics (2016), 18 (31), 21398-21411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)As the first study on metal carbide/cyanide boron clusterfullerenes, the geometries, energies, stabilities and electronic properties of four novel scandium cluster-contg. B80 buckyball derivs., namely Sc2C2@B80, Sc3C2@B80, Sc3CN@B80 and Sc3C2CN@B80, were investigated by means of d. functional theory computations. The rather favorable binding energies, which are very close to those of the exptl. abundant carbon fullerene analogs, suggest a considerable possibility to realize these doped boron clusterfullerenes. Their intra-cluster and cluster-cage bonding natures were thoroughly revealed by various theor. approaches. In contrast to carbon clusterfullerenes, in which the encaged non-metal atoms mainly play a stabilizing role in the metal clusters, the encapsulated carbon and nitrogen atoms inside the B80 cage covalently bond to the boron framework, resulting in strong cluster-cage interactions. Furthermore, IR spectra and 11B NMR spectra were simulated and fingerprint peaks were proposed to assist future exptl. characterization.
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297Mahdavifar, Z.; Ershadifar, M.; Farrokhnia, A. Electro-optical properties and structural stability perspectives of M3N and M2C2 (M = Sc, La) clusters encapsulated in B80 fullerene: A density functional theory study. J. Electron. Mater. 2018, 47, 550– 565, DOI: 10.1007/s11664-017-5813-1Google Scholar297https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVaju77F&md5=40dc243e7e37716d63287fc669f76eecElectro-Optical Properties and Structural Stability Perspectives of M3N and M2C2 (M = Sc, La) Clusters Encapsulated in B80 Fullerene: A Density Functional Theory StudyMahdavifar, Zabiollah; Ershadifar, Mina; Farrokhnia, AbdolhadiJournal of Electronic Materials (2018), 47 (1), 550-565CODEN: JECMA5; ISSN:0361-5235. (Springer)In this work, the stability of metal nitride/carbide cluster borofullerenes, namely M3N@B80/M2C2@B80, by means of d. functional theory (DFT) were evaluated. Detailed studies on M3N@B80/M2C2@B80 (M = Sc, La) series indicate that these structures have high thermodn. and kinetic stability due to the large value of calcd. embedding energies and HOMO-LUMO (H-L) energy gaps which indicate that the Sc3N, Sc2C2, La3N and La2C2 clusters can form viable stable complexes with B80 fullerene. Our computations show the Sc3N@B80 borofullerene has the highest thermodn. and kinetic stability and the obtained trend for thermodn. stability is Sc3N@B80 > Sc2C2@B80 > La2C2@B80 > La3N@B80. This trend is nearly the same as obtained for the kinetic stability trend; Sc3N@B80 > Sc2C2@B80 > La3N@B80 > La2C2@B80. The H-L energy gap of Sc3N@B80 and Sc2C2@B80 are 1.45 eV and 1.39 eV resp., much larger than La3@B80 (1.18 eV) and La2C2@B80 (1.13 eV), confirming that the nitride and carbide cluster borofullerenes have relatively high kinetic stability and could be isolated exptl. Also, substitution of Sc with La metal in the nitride and carbide clusters imposes a noticeable influence on the stability and electronic properties of M3N@B80/M2C2@B80 structures. Analyses of electronic structure and nearest distance between clusters and fullerene reveal that both covalent and ionic interactions coexist between cluster and boron atoms. Esp. in the case of La2C2@B80, the plausible electron configuration of it is [(La2C2)2-@B802+]. Addnl., the simulated adsorption spectra considered by means of time-dependent DFT calcns. as well as CD spectra show some different absorption bands in a broad region, which is helpful to further exptl. characterization. These results can promise some valuable assistance for the exptl. synthesis of M3N/M2C2@B80 structures because of high thermodn. and kinetic stability.
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298Muya, J. T.; Lijnen, E.; Nguyen, M. T.; Ceulemans, A. Encapsulation of small base molecules and tetrahedral/cubane-like clusters of group V atoms in the boron buckyball: A density functional theory study. J. Phys. Chem. A 2011, 115, 2268– 2280, DOI: 10.1021/jp107630qGoogle Scholar298https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisFWlsrg%253D&md5=505798be5e61811e4af364129cfd7562Encapsulation of Small Base Molecules and Tetrahedral/Cubane-Like Clusters of Group V Atoms in the Boron Buckyball: A Density Functional Theory StudyMuya, Jules Tshishimbi; Lijnen, Erwin; Nguyen, Minh Tho; Ceulemans, ArnoutJournal of Physical Chemistry A (2011), 115 (11), 2268-2280CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)A d. functional theory study of small base mols. and tetrahedral and cubane-like group V clusters encapsulated in B80 shows that the boron buckyball is a hard acid and prefers hard bases like NH3 or N2H4 to form stable off-centered complexes. In contrast, tetrahedral and cubane-like clusters of this family are metastable in the cage. The most favorable clusters are the mixed tetrahedral and cubane clusters formed by nitrogen and phosphorus atoms such as P2N2@B80, P3N@B80, and P4N4@B80. The boron cap atoms are electrophilic centers, and prefer mainly to react with electron rich nucleophilic sites. The stability of the complexes will be governed by the size and electron donating character of the encapsulated clusters. B80 forms stable complexes with hard materials where a bidentate interaction of the encapsulated mol. with two boron cap atoms is preferred over a single direct complex toward a single endohedral boron.
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299Wang, J.-T.; Chen, C.; Wang, E. G.; Wang, D.-S.; Mizuseki, H.; Kawazoe, Y. Highly stable and symmetric boron caged B@Co12@B80 core-shell cluster. Appl. Phys. Lett. 2009, 94, 133102, DOI: 10.1063/1.3111444Google Scholar299https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXksVeksrk%253D&md5=27290419a0a6e1bb234cd2cbb0e7c0ceHighly stable and symmetric boron caged B@Co12@B80 core-shell clusterWang, Jian-Tao; Chen, Changfeng; Wang, E. G.; Wang, Ding-Sheng; Mizuseki, H.; Kawazoe, Y.Applied Physics Letters (2009), 94 (13), 133102/1-133102/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The geometry, stability, and electronic properties of B@Co12@Bn and Co13@Bn clusters with a wide range n=55 up to 92 are studied by ab initio calcns. We find that B@Co12@B80 and Co13@B80 with closed B80 shell are two stable magic clusters with nearly perfect icosahedral symmetry, and B@Co12@B80 is more stable than Co13@B80 energetically. The strong core-shell bonding yields a very large energy gain of ∼30 eV. This high stability is attributed to the favorable closed-shell at. and electronic structures. The B@Co12@B80 exhibits a large highest occupied and lowest unoccupied energy gap (0.96 eV) that is close to the value for isolated B80 fullerene. (c) 2009 American Institute of Physics.
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300Zhai, H.-J.; Zhao, Y.-F.; Li, W.-L.; Chen, Q.; Bai, H.; Hu, H.-S.; Piazza, Z. A.; Tian, W.-J.; Lu, H.-G.; Wu, Y.-B. Observation of an all-boron fullerene. Nat. Chem. 2014, 6, 727– 731, DOI: 10.1038/nchem.1999Google Scholar300https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFygs7bJ&md5=740edf096553b09227c842cb3cbff427Observation of an all-boron fullereneZhai, Hua-Jin; Zhao, Ya-Fan; Li, Wei-Li; Chen, Qiang; Bai, Hui; Hu, Han-Shi; Piazza, Zachary A.; Tian, Wen-Juan; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Wei, Guang-Feng; Liu, Zhi-Pan; Li, Jun; Li, Si-Dian; Wang, Lai-ShengNature Chemistry (2014), 6 (8), 727-731CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)After the discovery of fullerene-C60, it took almost two decades for the possibility of boron-based fullerene structures to be considered. So far, there has been no exptl. evidence for these nanostructures, in spite of the progress made in theor. investigations of their structure and bonding. Here we report the observation, by photoelectron spectroscopy, of an all-boron fullerene-like cage cluster at B40- with an extremely low electron-binding energy. Theor. calcns. show that this arises from a cage structure with a large energy gap, but that a quasi-planar isomer of B40- with two adjacent hexagonal holes is slightly more stable than the fullerene structure. In contrast, for neutral B40 the fullerene-like cage is calcd. to be the most stable structure. The surface of the all-boron fullerene, bonded uniformly via delocalized σ and π bonds, is not perfectly smooth and exhibits unusual heptagonal faces, in contrast to C60 fullerene.
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301Chen, Q.; Li, W.-L.; Zhao, Y.-F.; Zhang, S.-Y.; Hu, H.-S.; Bai, H.; Li, H.-R.; Tian, W.-J.; Lu, H.-G.; Zhai, H.-J. Experimental and theoretical evidence of an axially chiral borospherene. ACS Nano 2015, 9, 754– 760, DOI: 10.1021/nn506262cGoogle Scholar301https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFeiu7nE&md5=fcf2a14cc55c04476918cb1bbce491ecExperimental and Theoretical Evidence of an Axially Chiral BorosphereneChen, Qiang; Li, Wei-Li; Zhao, Ya-Fan; Zhang, Su-Yan; Hu, Han-Shi; Bai, Hui; Li, Hai-Ru; Tian, Wen-Juan; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-Dian; Li, Jun; Wang, Lai-ShengACS Nano (2015), 9 (1), 754-760CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Chirality plays an important role in chem., biol., and materials science. The recent discovery of the B40-/0 borospherenes marks the onset of a class of boron-based nanostructures. Here we report the observation of axially chiral borospherene in the B39- nanocluster on the bases of photoelectron spectroscopy, global min. searches, and electronic structure calcns. Extensive structural searches in combination with d. functional and CCSD(T) calcns. show that B39- has a C3 cage global min. with a close-lying C2 cage isomer. Both the C3 and C2 B39- cages are chiral with degenerate enantiomers. The C3 global min. consists of three hexagons and three heptagons around the vertical C3 axis. The C2 isomer is built on two hexagons on the top and at the bottom of the cage with four heptagons around the waist. Both the C3 and C2 axially chiral isomers of B39- are present in the expt. and contribute to the obsd. photoelectron spectrum. The chiral borospherenes also exhibit three-dimensional aromaticity, featuring σ and π double delocalization for all valence electrons. Mol. dynamics simulations reveal that these chiral B39- cages are structurally fluxional above room temp., compared to the highly robust D2d B40 borospherene. The current findings add chiral members to the borospherene family and indicate the structural diversity of boron-based nanomaterials.
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302Wang, Y.-J.; Zhao, Y.-F.; Li, W.-L.; Jian, T.; Chen, Q.; You, X.-R.; Ou, T.; Zhao, X.-Y.; Zhai, H.-J.; Li, S.-D. Observation and characterization of the smallest borospherene, B28– and B28. J. Chem. Phys. 2016, 144, 064307, DOI: 10.1063/1.4941380Google Scholar302https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XisVansro%253D&md5=443d6f22cd9243c4b7af3ec212f80711Observation and characterization of the smallest borospherene, B28- and B28Wang, Ying-Jin; Zhao, Ya-Fan; Li, Wei-Li; Jian, Tian; Chen, Qiang; You, Xue-Rui; Ou, Ting; Zhao, Xiao-Yun; Zhai, Hua-Jin; Li, Si-Dian; Li, Jun; Wang, Lai-ShengJournal of Chemical Physics (2016), 144 (6), 064307/1-064307/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Free-standing boron nanocages or borospherenes have been obsd. recently for B40- and B40. There is evidence that a family of borospherenes may exist. However, the smallest borospherene is still not known. Here, we report exptl. and computational evidence of a seashell-like borospherene cage for B28- and B28. Photoelectron spectrum of B28- indicated contributions from different isomers. Theor. calcns. showed that the seashell-like B28- borospherene is competing for the global min. with a planar isomer and it is shown to be present in the cluster beam, contributing to the obsd. photoelectron spectrum. The seashell structure is found to be the global min. for neutral B28 and the B28- cage represents the smallest borospherene obsd. to date. It is composed of two triangular close-packed B15 sheets, interconnected via the three corners by sharing two boron atoms. The B28 borospherene was found to obey the 2(n + 1)2 electron-counting rule for spherical aromaticity. (c) 2016 American Institute of Physics.
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303Lv, J.; Wang, Y.; Zhu, L.; Ma, Y. B38: An all-boron fullerene analogue. Nanoscale 2014, 6, 11692– 11696, DOI: 10.1039/C4NR01846JGoogle Scholar303https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFSgtLnO&md5=266ad562f1ec6aca93205054e82d6d68B38: an all-boron fullerene analogueLv, Jian; Wang, Yanchao; Zhu, Li; Ma, YanmingNanoscale (2014), 6 (20), 11692-11696CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Fullerene-like structures formed by elements other than carbon have long been sought. Finding all-boron (B) fullerene-like structures is challenging due to the geometrical frustration arising from competitions among various structural motifs. We report here the prediction of a B38 fullerene analog found through first-principles swarm structure searching calcns. The structure is highly sym. and consists of 56 triangles and four hexagons, which provide an optimal void in the center of the cage. Energetically, it is more favorable than the planar and tubular structures, and possesses an unusually high chem. stability: a large energy gap (∼2.25 eV) and a high double aromaticity, superior to those of most arom. quasi-planar B12 and double-ring B20 clusters. Our findings represent a key step forward towards to the understanding of structures of medium-sized B clusters and map out the exptl. direction of the synthesis of an all-B fullerene analog.
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304BaáTai, T.; ThoáNguyen, M. A new chiral boron cluster B44 containing nonagonal holes. Chem. Commun. 2016, 52, 1653– 1656, DOI: 10.1039/C5CC09111JGoogle ScholarThere is no corresponding record for this reference.
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305Xu, Q.; Liu, C.; Yang, L.; Jin, P.; Tang, C.; Chen, Z. Computational investigation on MBn (M = Li-Cs, Be-Ba, Sc-La and Ti; n = 28 and 38). J. Mol. Model. 2016, 22, 184, DOI: 10.1007/s00894-016-3055-4Google Scholar305https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2s3hsVaqsQ%253D%253D&md5=e5b2f3ef9129942bf9ce1184a4223055Computational investigation on MB n (M = Li-Cs, Be-Ba, Sc-La and Ti; n = 28 and 38)Xu Qianhui; Liu Chang; Yang Le; Jin Peng; Tang Chengchun; Chen ZhongfangJournal of molecular modeling (2016), 22 (8), 184 ISSN:.Differing from the weakly antiaromatic B80 buckyball, the medium-sized C 1-B28 and D 2h -B38, as well as their mono- to tetra-anions, are highly aromatic, as indicated by the negative nucleus-independent chemical shifts (NICSs) at their cage centers. The interior cavities and high aromaticity of the B28 and B38 cages render them very promising hosts to accommodate diverse metal atoms. Accordingly, we carried out systematic density functional theory (DFT) computations on the structures, stabilities and electronic properties of metalloborofullerenes MB n (M = Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Sc, Y, La and Ti; n = 28 and 38). Among them, besides the recently reported M@B38(M = Sc, Y and Ti) [Lu et al. (2015) Phys Chem Chem Phys 17:20897-20902], Ti@B28 and M@B38 (M = Ca and La) also favor endohedral structures with large binding energies, and are suggested promising targets for experimental applications. Note that Ti@B28 is the first endohedral derivative based on the new B28 fullerene, and La@B38 features the largest metal size inside a B38 cage thus far. These endohedral derivatives, as exemplified by Ca@B38, may exhibit σ and π double aromaticity over the whole cage surface, indicating their considerable stability. In contrast, the other metals prefer to reside at the exterior cage surface, due mainly to the mismatch of their sizes with the boron cages, though the size match is not the only factor to determine their doping form. Furthermore, the infrared absorption spectra and (11)B nuclear magnetic resonance spectra of the three new M@B n complexes were computed to assist future experimental characterization. Graphical Abstract Putting more metals into medium-sized boron cages!
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306Bai, H.; Chen, Q.; Zhai, H. J.; Li, S. D. Endohedral and exohedral metalloborospherenes: M@B40 (M = Ca, Sr) and M&B40 (M = Be, Mg). Angew. Chem., Int. Ed. 2015, 54, 941– 945, DOI: 10.1002/anie.201408738Google Scholar306https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFKmtLnF&md5=26b2441461fee9e44098c193df5633ceEndohedral and Exohedral Metalloborospherenes: M@B40 (M = Ca, Sr) and M&B40 (M = Be, Mg)Bai, Hui; Chen, Qiang; Zhai, Hua-Jin; Li, Si-DianAngewandte Chemie, International Edition (2015), 54 (3), 941-945CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The recent discovery of the all-boron fullerenes or borospherenes, D2d B40-/0, paves the way for borospherene chem. Here we report a d. functional theory study on the viability of metalloborospherenes: endohedral M@B40 (M = Ca, Sr) and exohedral M and B40 (M = Be, Mg). Extensive global structural searches indicate that Ca@B40 (1, C2v, 1A1) and Sr@B40 (3, D2d, 1A1) possess almost perfect endohedral borospherene structures with a metal atom at the center, while Be and B40 (5, Cs, 1A') and Mg and B40 (7, Cs, 1A') favor exohedral borospherene geometries with a η7-M atom face-capping a heptagon on the waist. Metalloborospherenes provide indirect evidence for the robustness of the borospherene structural motif. The metalloborospherenes are characterized as charge-transfer complexes (M2+B402-), where an alk. earth metal atom donates two electrons to the B40 cage. The high stability of endohedral Ca@B40 (1) and Sr@B40 (3) is due to the match in size between the host cage and the dopant. Bonding analyses indicate that all 122 valence electrons in the systems are delocalized as σ or π bonds, being distributed evenly on the cage surface, akin to the D2d B40 borospherene.
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307Jin, P.; Hou, Q.; Tang, C.; Chen, Z. Computational investigation on the endohedral borofullerenes M@B40 (M = Sc, Y, La). Theor. Chem. Acc. 2015, 134, 13, DOI: 10.1007/s00214-014-1612-4Google ScholarThere is no corresponding record for this reference.
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308Fa, W.; Chen, S.; Pande, S.; Zeng, X. C. Stability of metal-encapsulating boron fullerene B40. J. Phys. Chem. A 2015, 119, 11208– 11214, DOI: 10.1021/acs.jpca.5b07173Google Scholar308https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1yltrfP&md5=dfbbe68e8613fbd2bbfd2d2b389f7c5bStability of Metal-Encapsulating Boron Fullerene B40Fa, Wei; Chen, Shuang; Pande, Seema; Zeng, Xiao ChengJournal of Physical Chemistry A (2015), 119 (45), 11208-11214CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The structural stability of MB40 (M = Li, Na, K, Ba, and Tl) is investigated on the basis of d.-functional theory calcns. at the PBE0 level. Particular attention is placed on the relative stability between the endohedral and exohedral configurations of metalloborospherenes. It is found that the Na and Ba atoms can be stably encapsulated inside the B40 cage, whereas the Li, K, and Tl atoms favor the exohedral configuration where the dopant caps one of heptagons of B40 cage. In-depth anal. of the endohedral vs. exohedral configurations with different dopants suggests that besides the comparable at. size with the cage size, another key factor that can affect stability of endohedral vs. exohedral configuration is the interaction between the dopant and B atoms. The IR spectra of the endohedral C2v Na@B40 and exohedral Cs Na&B40 clusters are also computed, from which some useful spectral indicators may be used for identification of the structures in the future expts.
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309Shah, E. V.; Roy, D. R. Sc3N and Sc2C2 encapsulated B40: Smarter than its carbon analogue. Phys. E 2016, 84, 354– 360, DOI: 10.1016/j.physe.2016.08.002Google Scholar309https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhtlegs7vI&md5=d908e2eb88e70a9b2755af3f7b5b8773Sc3N and Sc2C2 encapsulated B40: Smarter than its carbon analogueShah, Esha V.; Roy, Debesh R.Physica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2016), 84 (), 354-360CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)A detailed comparative investigation on the recently synthesized B40 and C40 along with their metal nitride (Sc3N)and carbide (Sc2C2) encapsulated endohedral fullerenes, is performed under d. functional theory for the first time. The structures, electronic, thermodn. and magnetic properties of all the considered compds. are explored in detail. The present study identifies borospherene (B40) and its encapsulated nitride (Sc3N@B40) and carbide (Sc2C2@B40) endohedral borofullerenes as the better candidates for future novel nano-applications compared to their carbon bucky ball analogs.
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310Shakerzadeh, E.; Biglari, Z.; Tahmasebi, E. M@B40 (M = Li, Na, K) serving as a potential promising novel NLO nanomaterial. Chem. Phys. Lett. 2016, 654, 76– 80, DOI: 10.1016/j.cplett.2016.05.014Google Scholar310https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XnvFaisb4%253D&md5=974937c96f3d733c328a5a324104bba2M@B40 (M = Li, Na, K) serving as a potential promising novel NLO nanomaterialShakerzadeh, Ehsan; Biglari, Zeinab; Tahmasebi, ElhamChemical Physics Letters (2016), 654 (), 76-80CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)D. functional theory (DFT) calcns. have carried out to investigate the nonlinear optical response of the B40 fullerene by interaction with the alkali metals (Li, Na, K). The results reveal that the interacted fullerenes are energetically favorable. The B40 electronic properties are strongly sensitive to the interaction with the alkali metals. Furthermore, the adsorption of the alkali metals over the B40 hexagonal ring remarkably enhances the first hyperpolarizability up to 23111.72 a.u. Therefore, the B40 fullerene interacted with the alkali metals could be introduced as a promising innovative nonlinear optical boron-based nanomaterial.
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311Li, S.-X.; Zhang, Z.-P.; Long, Z.-W.; Qin, S.-J. Structures, stabilities and spectral properties of metalloborospherenes MB0/–40 (M = Cu, Ag, and Au). RSC Adv. 2017, 7, 38526– 38537, DOI: 10.1039/C7RA05932AGoogle Scholar311https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1yhsL3K&md5=4835c9398413c9f0065dcc587c9f379cStructures, stabilities and spectral properties of metalloborospherenes MB0/-40 (M = Cu, Ag, and Au)Li, Shi-Xiong; Zhang, Zheng-Ping; Long, Zheng-Wen; Qin, Shui-JieRSC Advances (2017), 7 (61), 38526-38537CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The discovery of borospherene B40 marks the onset of a new class of boron fullerenes and it is of current interest in chem. physics and, in particular, boron chem. In this work, d. functional theory (DFT) and time-dependent d. functional theory (TD-DFT) calcns. are carried out to study the structures, stabilities, photoelectron spectra, IR spectra, Raman spectra and electronic absorption spectra of metalloborospherenes MB0/-40 (M = Cu, Ag, and Au). It is found that Cu, Ag and Au atoms can form stable exohedral metalloborospherenes M&B0/-40 (M = Cu, Ag, and Au) and endohedral metalloborospherenes M@B0/-40 (M = Cu, Ag, and Au). In addn., the relative energies of these metalloborospherenes suggest that Cu, Ag and Au atoms favor the exohedral configuration. The Cu atom favors an exohedral geometry with the dopant face-capping a heptagon on the side surface (η7-Cu), whereas Ag and Au atoms favor exohedral geometries with the dopant bonding a side boron atom of the hexagonal ring. The calcd. spectra suggest that doping of metal atoms in borospherene B40 can change the spectral features since the extra metal atoms can modify the electronic structure of borospherene B40. The addn. of metal atoms can lead to more IR and Raman active modes and red shift the electronic absorption spectra. The calcd. results also show that metalloborospherenes MB0/-40 (M = Cu, Ag, and Au) have different and meaningful spectral features, insight into the spectral properties is important to understand the compds. and reveal their potential applications. These spectral features can be readily compared with future spectroscopy measurements and used as fingerprints to identify and distinguish the metalloborospherenes MB0/-40 (M = Cu, Ag, and Au).
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312Jin, P.; Yang, L.; Liu, C.; Hou, Q.; Li, L. Computational prediction of the endohedral metalloborofullerenes Tin@B40 (n = 1, 2). Theor. Chem. Acc. 2017, 136, 56, DOI: 10.1007/s00214-017-2087-xGoogle ScholarThere is no corresponding record for this reference.
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313Xi, C.; Yang, L.; Liu, C.; You, P.; Li, L.; Jin, P. Lanthanide metals in the boron cages: Computational prediction of M@Bn (M = Eu, Gd; n = 38, 40). Int. J. Quantum Chem. 2018, 118, e25576 DOI: 10.1002/qua.25576Google ScholarThere is no corresponding record for this reference.
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314Yong, Y.; Su, X.; Kuang, Y.; Li, X.; Lu, Z. B40 and M@B40 (M = Li and Ba) fullerenes as potential molecular sensors for acetone detection A first-principles study. J. Mol. Liq. 2018, 264, 1– 8, DOI: 10.1016/j.molliq.2018.05.046Google Scholar314https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXpsVajsb4%253D&md5=a335b7e0ea6029863f2713bd639211e7B40 and M@B40 (M=Li and Ba) fullerenes as potential molecular sensors for acetone detection: A first-principles studyYong, Yongliang; Su, Xiangying; Kuang, Yanmin; Li, Xiaohong; Lu, ZhanshengJournal of Molecular Liquids (2018), 264 (), 1-8CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)The adsorption of acetone on B40 and M@B40 (M=Li and Ba) has been studied by means of d. functional theory calcns. It is demonstrated that the acetone mol. can easily chemisorb on the B40 and M@B40 from physisorption states with very small energy barriers. The adsorption strength is moderate and the charge transfer between acetone and B40 (or M@B40) is apparent. Moreover, the M-doping can slightly enhance the adsorption strength. The elec. cond. of B40 (or M@B40) changes obviously due to the acetone adsorption. The recovery times for B40 or M@B40, in particular for B40 at T = 300 K are quite short, very different from NH3 or NO2 adsorbed on B40. Our results suggest that the B40 and M@B40 (M=Li and Ba) can be viewed as high sensitive mol. sensors for acetone detection with short recovery time.
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315Yu, T.; Gao, Y.; Xu, D.; Wang, Z. Actinide endohedral boron clusters: A closed-shell electronic structure of U@B40. Nano Res. 2018, 11, 354– 359, DOI: 10.1007/s12274-017-1637-9Google Scholar315https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtlygurvF&md5=84944c022eb618519902981e6cdd6f53Actinide endohedral boron clusters: A closed-shell electronic structure of U@B40Yu, Tianrong; Gao, Yang; Xu, Dexuan; Wang, ZhigangNano Research (2018), 11 (1), 354-359CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)The distinctive electronic bonding properties of actinide-contg. clusters have made them the subject of increased attention. Herein, we use d. functional theory calcns. to examine a unique actinide-encapsulated U@B40 cage structure, revealing that it exhibits a 32-electron (1S21P61D101F14) closed-shell singlet configuration in which all s, p, d, and f shells of the U atom are filled. Furthermore, the binding energy of 8.22 eV calcd. for this cluster implies considerable stability, and the simulated IR and Raman spectra feature U-B40 stretching and pure B40 breathing vibration modes, resp. These spectral characteristics may aid future exptl. investigations. Thus, this work not only describes a new member of the superat. family, but also provides a method of encapsulating radioactive actinides. [Figure not available: see fulltext.].
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316Chojecki, M.; Yourdkhani, S.; Rutkowska-Zbik, D.; Korona, T. Stability of endo-and exohedral complexes of all-boron fullerene B40. Comput. Theor. Chem. 2018, 1133, 7– 17, DOI: 10.1016/j.comptc.2018.04.007Google Scholar316https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXotlGntr8%253D&md5=99d610fb0d8685fc65e1db3ada9c963fStability of endo- and exohedral complexes of all-boron fullerene B40Chojecki, Michal; Yourdkhani, Sirous; Rutkowska-Zbik, Dorota; Korona, TatianaComputational & Theoretical Chemistry (2018), 1133 (), 7-17CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)In a recent publication [Nature Chem., 6, 727 (2014)] the synthesis and properties of a new all-boron fullerene analog, B40, have been reported, and a possibility of utilizing the B40 mol. as a hydrogen storage has been postulated. Therefore, in this contribution we study the stability of endo- and exohedral complexes with the hydrogen mol. and several other small mols., such as N2, H2O, and CO2. The examn. of binding and interaction energies obtained by symmetry-adapted perturbation theory and by supermol. approaches shows that among the studied endohedral complexes only the one with H2 inside the cage is possibly weakly stabilized by the complexation, while all other mols. clearly exhibit too large repulsion, which cannot be counterweighted by attractive components of the interaction energy. An addn. of the zero-point vibrational correction to the H2@B40 binding energy changes the balance of the attractive and repulsive contributions in favor of repulsion, so that finally also this endohedral complex is thermodynamically unstable at zero Kelvin. The exohedral min. are stable in all the cases, and are mostly bound by dispersion.
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317Maniei, Z.; Shakerzadeh, E.; Mahdavifar, Z. Theoretical approach into potential possibility of efficient NO2 detection via B40 and Li@B40 fullerenes. Chem. Phys. Lett. 2018, 691, 360– 365, DOI: 10.1016/j.cplett.2017.11.045Google Scholar317https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVygtb3P&md5=e929619105180d608ddf1a2ce99da717Theoretical approach into potential possibility of efficient NO2 detection via B40 and Li@B40 fullerenesManiei, Zeinab; Shakerzadeh, Ehsan; Mahdavifar, ZabiollahChemical Physics Letters (2018), 691 (), 360-365CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The potential applicability of B40 and Li@B40 fullerenes as chem. sensors for NO2 pollutant detection was studied by employing DFT calcns. NO2 mol. is remarkably chemisorbed on the surface of both B40 and Li@B40 fullerenes. Electronic properties of B40 and Li@B40 fullerenes change after NO2 chemisorption. Although the HOMO-LUMO energies gap (HLG) of B40 is considerably decreased after NO2 chemisorption, the HLG of Li@B40 are significantly enhanced after NO2 adsorption. B40 and Li@B40 fullerenes are introduced as novel promising chem. sensor for NO2 pollutant.
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318An, Y.; Zhang, M.; Wu, D.; Fu, Z.; Wang, T.; Xia, C. Electronic transport properties of the first all-boron fullerene B40 and its metallofullerene Sr@B40. Phys. Chem. Chem. Phys. 2016, 18, 12024– 12028, DOI: 10.1039/C6CP01096BGoogle Scholar318https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XkvFOnurw%253D&md5=5b7dba58890b5043711fb12d9eed5902Electronic transport properties of the first all-boron fullerene B40 and its metallofullerene Sr@B40An, Yipeng; Zhang, Mengjun; Wu, Dapeng; Fu, Zhaoming; Wang, Tianxing; Xia, CongxinPhysical Chemistry Chemical Physics (2016), 18 (17), 12024-12028CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The newly-discovered B40 is the first exptl. obsd. all-boron fullerene and has potential applications in mol. devices. Herein, we report the electronic transport properties of B40 and its metallofullerene, Sr@B40, using the first-principles technique. We obtain the conductance of B40 fullerene, which is about 130 μS and can be increased by embedding a strontium metal atom in the cage due to the decreased energy gap. Both the current-voltage (I-V) curves of B40 and Sr@B40 present perfect linear characteristics. Intuitively, it is assumed that the electron currents pass through the B40 fullerene mainly along the surface B-B bonds, while two types of new B-Sr-B bond currents and B→Sr→B hopping currents are presented for Sr@B40 due to Sr acting as a bridge. This study provides valuable information for the potential applications of future borospherene-based mol. devices.
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319Wang, W.; Guo, Y.-D.; Yan, X.-H. The spin-dependent transport of transition metal encapsulated B40 fullerene. RSC Adv. 2016, 6, 40155– 40161, DOI: 10.1039/C6RA00179CGoogle Scholar319https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmsF2gurw%253D&md5=aaffc7c58fd759ea8faaee262f098c34The spin-dependent transport of transition metal encapsulated B40 fullereneWang, Wei; Guo, Yan-Dong; Yan, Xiao-HongRSC Advances (2016), 6 (46), 40155-40161CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The all-boron fullerene, B40, has been successfully exptl. synthesized [Zhai et al., Nat. Chem.,6, 727 (2014)]. Compared with C60, the smaller cage-like structure is more suitable to dope with metal atoms. Based on d. functional theory and nonequil. Green's function method, we investigate the spin-dependent transport of transition metal atom-encapsulated B40 fullerene, i.e., X@B40 (X = Fe, Mn, Ni, and Co), which are contacted with Au electrodes. The transmission spectra of Fe- and Mn-doped systems are spin-polarized, and those of Ni-doped ones are spin-unpolarized. Interestingly, in Co-doped systems, the transmission is highly spin-polarized for the hexagonal doping case, but spin-unpolarized for the heptagonal doping case. Further investigation shows that the screening effect of the electrodes on the magnetism of Co is the underlying phys. mechanism, which is found to be robust to the electrode material. We believe that these findings are very useful for developing spintronic devices.
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320Mahdavifar, Z.; Poulad, M. Stability prediction of pristine and metal endohedral borofullerenes: Computational approach. J. Mol. Liq. 2016, 219, 1144– 1156, DOI: 10.1016/j.molliq.2016.03.027Google Scholar320https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xot1SgsbY%253D&md5=4071ab97b4461b205ccfb6ec41d70d43Stability prediction of pristine and metal endohedral borofullerenes: Computational approachMahdavifar, Zabiollah; Poulad, MarziyehJournal of Molecular Liquids (2016), 219 (), 1144-1156CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)Based on DFT calcns., the structure, stability and electronic properties of pristine borofullerenes (Bn with n = 20, 30, 40, 50, 60) and their endohedral Zn@Bn fullerenes were investigated. The binding energy per atom has been calcd. for pristine Bn, showing that the stability grows with increasing fullerene size, where the most stable structure is related to the B50 fullerene with Eb = - 5.65 eV/atom. The stability of these structures are predicted in the order B50 ∼ B60 > B40 > B30 > B20. On the other hand, the largest H-L energy gap is belonging to the smallest cluster, B20, with energy gap about 1.15 eV. This is an interesting result since it means that the most stable structure for the Bn fullerenes does not necessary have to be a large H-L energy gap. To testify the effect of Zn encapsulation on the stability of Bn fullerenes, the Zn@Bn fullerene are also considered. Due on stabilization energy, the stability of Zn@Bn fullerenes are predicted in the order Zn@B30 > Zn@B20 > Zn@B60 > Zn@B40 > Zn@B50. Based on these results, the encapsulating process has the most influence on B30 and B50 fullerenes. As results, the method of Zn encapsulating is very successful to stabilize small Bn fullerene. In the case of Zn@B50, this structure is extremely unstable whereas the pristine B50 is favorable structure. On the other hand, when the Zn metal atom encapsulated into the fullerenes, a dramatically mutation in Fermi level is occurred which imply to change in energy gap.
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321Wang, C.-Z.; Bo, T.; Lan, J.-H.; Wu, Q.-Y.; Chai, Z.-F.; Gibson, J. K.; Shi, W.-Q. Ultrastable actinide endohedral borospherenes. Chem. Commun. 2018, 54, 2248– 2251, DOI: 10.1039/C7CC09837EGoogle Scholar321https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit12gsr4%253D&md5=751c5ab59619520c687b2a918f80eda8Ultrastable actinide endohedral borospherenesWang, Cong-Zhi; Bo, Tao; Lan, Jian-Hui; Wu, Qun-Yan; Chai, Zhi-Fang; Gibson, John K.; Shi, Wei-QunChemical Communications (Cambridge, United Kingdom) (2018), 54 (18), 2248-2251CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Since the discovery of the first all-boron fullerenes B40-/0, metal-doped borospherenes have received extensive attention. So far, in spite of theor. efforts on metalloborospherenes, the feasibility of actinide analogs remains minimally explored. Here we report a series of actinide borospherenes AnBn (An = U, Th; n = 36, 38, and 40) using DFT-PBE0 calcns. All the AnBn complexes are found to possess endohedral structures (An@Bn) as the global min. In particular, U@B36 (C2h, 3Ag) and Th@B38 (D2h, 1Ag) exhibit nearly ideal endohedral borospherene structures. The C2h U@B36 and D2h Th@B38 complexes are predicted to be highly robust both thermodynamically and dynamically. In addn. to the actinide size match to the cage, the covalent character of the metal-cage bonding in U@B36 and Th@B38 affords further stabilization. Bonding anal. indicates that U@B36 and Th@B38 can be qualified as 32-electron systems, and Th@B38 exhibits 3D aromaticity with σ plus π double delocalization bonding. The results demonstrate that doping with appropriate actinide atoms is promising to stabilize diverse borospherenes, and may provide routes for borospherene modification and functionalization.
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322Chen, Q.; Li, H.-R.; Tian, W.-J.; Lu, H.-G.; Zhai, H.-J.; Li, S.-D. Endohedral charge-transfer complex Ca@B37–: Stabilization of a B373– borospherene trianion by metal-encapsulation. Phys. Chem. Chem. Phys. 2016, 18, 14186– 14190, DOI: 10.1039/C6CP02369JGoogle Scholar322https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XntlSmsrg%253D&md5=a702de1ccbed2cade0ccabc0ee5011b0Endohedral charge-transfer complex Ca@B37-: stabilization of a B373- borospherene trianion by metal-encapsulationChen, Qiang; Li, Hai-Ru; Tian, Wen-Juan; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-DianPhysical Chemistry Chemical Physics (2016), 18 (21), 14186-14190CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Based on extensive first-principles theory calcns., DFT-PBE0 and CCSD(T), the authors present results on the endohedral charge-transfer complex, Cs Ca@B37-, which contains a 3D arom. fullerene-like Cs B373- trianion composed of interwoven boron double chains with twelve delocalized multicenter π bonds (12 mc-2e π, m = 5, 6) over a σ skeleton, completing the Bnq borospherene family (q = n - 40) in the size range of n = 36-42.
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323Lu, Q. L.; Luo, Q. Q.; De Li, Y.; Huang, S. G. DFT study on endohedral and exohedral B38 fullerenes: M@B38 (M = Sc, Y, Ti) and M&B38 (M = Nb, Fe, Co, Ni). Phys. Chem. Chem. Phys. 2015, 17, 20897– 20902, DOI: 10.1039/C5CP03378KGoogle Scholar323https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtF2mtLrL&md5=ed48052dba12354dc15df38823e918edDFT study on endohedral and exohedral B38 fullerenes: M@B38 (M = Sc, Y, Ti) and M&B38 (M = Nb, Fe, Co, Ni)Lu, Qi Liang; Luo, Qi Quan; Li, Yi De; Huang, Shou GuoPhysical Chemistry Chemical Physics (2015), 17 (32), 20897-20902CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures, stabilities and electronic properties of endohedral and exohedral B38 fullerenes with transition metal atoms (M = Sc, Y, Ti, Nb, Fe, Co, Ni) are studied using all-electron d. functional theory. M@B38 (M = Sc, Y, Ti) possess endohedral structures as their lowest energy structures, while Nb, Fe, Co and Ni atoms favor the coordination of B38 fullerenes in an exohedral manner. Sizable HOMO-LUMO gaps and high binding energies imply the viability of M@B38 towards exptl. realization. The distributions of electron d. and frontier orbitals are analyzed in detail. The anal. of vertical ionization potential and vertical electron affinity indicates that M@B38 are good electron acceptors and bad electron donors.
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324Chen, Q.; Li, H.-R.; Miao, C.-Q.; Wang, Y.-J.; Lu, H.-G.; Mu, Y.-W.; Ren, G.-M.; Zhai, H.-J.; Li, S.-D. Endohedral Ca@B38: Stabilization of a B382– borospherene dianion by metal encapsulation. Phys. Chem. Chem. Phys. 2016, 18, 11610– 11615, DOI: 10.1039/C5CP06169EGoogle Scholar324https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVGgt7nJ&md5=765424a907e795682d6fe7f466d7cbdaEndohedral Ca@B38: stabilization of a B382- borospherene dianion by metal encapsulationChen, Qiang; Li, Hai-Ru; Miao, Chang-Qing; Wang, Ying-Jin; Lu, Hai-Gang; Mu, Yue-Wen; Ren, Guang-Ming; Zhai, Hua-Jin; Li, Si-DianPhysical Chemistry Chemical Physics (2016), 18 (17), 11610-11615CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Based on extensive global-min. searches and first-principles electronic structure calcns., we present the viability of an endohedral metalloborospherene Cs Ca@B38 (1) which contains a Cs B382- (2) dianion composed of interwoven boron double chains with a σ + π double delocalization bonding pattern, extending the Bnq (q = n - 40) borospherene family from n = 39-42 to n = 38. Transition metal endohedral complexes Cs M@B38 (M = Sc, Y, Ti) (3, 5, 7) based on Cs B382-(2) are also predicted.
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325Chen, Q.; Gao, T.; Tian, W.-J.; Bai, H.; Zhang, S.-Y.; Li, H.-R.; Miao, C.-Q.; Mu, Y.-W.; Lu, H.-G.; Zhai, H.-J. Endohedral C3Ca@B39+ and C2Ca@B39+: Axially chiral metalloborospherenes based on B39–. Phys. Chem. Chem. Phys. 2015, 17, 19690– 19694, DOI: 10.1039/C5CP03178HGoogle Scholar325https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFaiu7vO&md5=2af8055cd0ece518a07e048304b48036Endohedral C3 Ca@B39+ and C2 Ca@B39+: axially chiral metalloborospherenes based on B39-Chen, Qiang; Gao, Ting; Tian, Wen-Juan; Bai, Hui; Zhang, Su-Yan; Li, Hai-Ru; Miao, Chang-Qing; Mu, Yue-Wen; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-DianPhysical Chemistry Chemical Physics (2015), 17 (30), 19690-19694CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Using the newly discovered borospherenes C3 B39- and C2 B39- as mol. devices and based on extensive global-min. searches and first-principles calcns., we present herein the possibility of the first axially chiral metalloborospherenes C3 Ca@B39+ (1, 1A) and C2 Ca@B39+ (2, 1A), which are the global min. and the second lowest-lying isomer of CaB39+, resp. These metalloborospherene species turn out to be charge-transfer complexes Ca2+@B39- in nature, with the Ca center on the C3 or C2 mol. axis donating one electron to the B39 cage which behaves like a superhalogen. MO analyses indicate that C3/C2 Ca2+@B39- possess the universal bonding pattern of σ plus π double delocalization, similar to their C3/C2 B39- parents. Mol. dynamics simulations show that both C3 Ca@B39+ (1) and C2 Ca@B39+ (2) are dynamically stable at 200 K, with the former starting to fluctuate structurally at 300 K and the latter at 400 K, again similar to C3/C2 B39-. The IR and Raman spectra of C3/C2 Ca@B39+ (1/2) are simulated and compared with those of C3/C2 B39- to facilitate their forthcoming exptl. characterization.
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326Stasyuk, A. J.; Solà, M. Does the endohedral borospherene supersalt FLi2@B39 maintain the “super” properties of its subunits?. Phys. Chem. Chem. Phys. 2017, 19, 21276– 21281, DOI: 10.1039/C7CP02550EGoogle Scholar326https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1WhtrrL&md5=bd2f0664cc66cff5cc9f1f75900d87eaDoes the endohedral borospherene supersalt FLi2@B39 maintain the "super" properties of its subunits?Stasyuk, A. J.; Sola, M.Physical Chemistry Chemical Physics (2017), 19 (32), 21276-21281CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The behavior of the entirely unique system represented by superalkaline species incorporated into a superhalogen cage has been studied using d. functional theory with hybrid functionals and the triple-ξ quality basis set level of theory. The singlet ground state and triplet excited state of an FLi2@B39 borospherene complex as well as its cationic and anionic doublet ground states have been investigated. Only the encapsulation of FLi2+ into B39 in FLi2@B39+ is a thermodynamically unfavorable process. All other systems are stabilized during encapsulation most likely via an unpaired electron delocalization process and electrostatic interaction. The calcns. revealed that superhalogen and superalkaline properties inherent in the sepd. fragments are lost in FLi2@B39 complexes. The applicability of vertically estd. ionization potentials and electron affinities instead of adiabatic ones for description of such systems has been demonstrated.
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327Yang, L.; Jin, P.; Hou, Q.; Li, L. Endohedral metalloborofullerenes M@B44 (M = Ca, Sr, Ba): A computational investigation. J. Mol. Model. 2016, 22, 297, DOI: 10.1007/s00894-016-3170-2Google Scholar327https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sjhtlCmuw%253D%253D&md5=7535d5fced4c87abef0a622b0d7e5988Endohedral metalloborofullerenes M@B44 (M = Ca, Sr, Ba): a computational investigationYang Le; Jin Peng; Hou Qinghua; Li LanlanJournal of molecular modeling (2016), 22 (12), 297 ISSN:.For the first time, the structures, stabilities and electronic properties of alkaline-earth metal doped B44 fullerenes were investigated by means of density functional theory calculations. Our results reveal that M@B44 (M = Ca, Sr, Ba) possess endohedral configurations as their lowest energy structures, whereas the exohedral form is favored when metal is Be or Mg. The large binding energies and sizable HOMO-LUMO gap energies of Ca@B44, Sr@B44 and Ba@B44 suggest the considerable possibility to achieve these novel endohedral borofullerenes experimentally. Born-Oppenheimer molecular dynamics (BO-MD) simulations at various temperatures further confirmed the extreme dynamic stabilities of these endohedral complexes. Their bonding patterns were also analyzed in detail. Finally, we simulated their infrared absorption spectra and (11)B nuclear magnetic resonance spectra to help future structural characterization. Graphical Abstract Stuffing B44 fullerene with metals.
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328Zhao, R.-N.; Yuan, Y.-H.; Han, J.-G.; Duan, Y. Geometries, stabilities, and electronic properties of tungsten encapsulated nanosize irregular Bn (n = 20, 24, 28, and 32) fullerenes: A density functional investigation. Chem. Phys. Lett. 2016, 648, 41– 46, DOI: 10.1016/j.cplett.2016.01.052Google Scholar328https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhtl2rs7o%253D&md5=470beb36f4d1c00ba25a7d57545edda7Geometries, stabilities, and electronic properties of tungsten encapsulated nanosize irregular Bn (n = 20, 24, 28, and 32) fullerenes: A density functional investigationZhao, Run-Ning; Yuan, Yan-Hong; Han, Ju-Guang; Duan, YuhuaChemical Physics Letters (2016), 648 (), 41-46CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Geometries, relative stabilities, and HOMO-LUMO gaps of W@Bn clusters were calcd. using the DFT-mPW3PBE method. The calcd. averaged at. binding energies reveal that the W@B20 has enhanced stability over other clusters. Interestingly, the irregular W@B24 fullerene with bigger HOMO-LUMO gap is supposed to have stronger chem. activity. Moreover, the interactions between W and B24 cage is strongest one based upon the calcd. binding energy between W and B cage. The irregular W@B24 cage is a nonpolar mol.
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329Liu, L.; Osorio, E.; Heine, T. The importance of dynamics studies on the design of sandwich structures: A CrB24 case. Phys. Chem. Chem. Phys. 2016, 18, 18336– 18341, DOI: 10.1039/C6CP02445AGoogle Scholar329https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xps1amsbs%253D&md5=8ad64f29bd9e0b56d65a1c502e0cecdeThe importance of dynamics studies on the design of sandwich structures: a CrB24 caseLiu, Lei; Osorio, Edison; Heine, ThomasPhysical Chemistry Chemical Physics (2016), 18 (27), 18336-18341CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Computational prediction and design of sandwich structures have drawn a lot of attention because of their interesting bond characteristics and broad applications. Most studies focus on the thermodn. stability. In this study, we performed a series of Born-Oppenheimer mol. dynamics (BO-MD) simulations to investigate the dynamic stability of the well-known sandwich structure CrB24. The aim was to find at which temp. the sandwich structure is stable. The MD results showed that the sandwich structure has an extremely poor dynamic stability. Addnl., one highly sym. endohedral structure with a chromium atom at the center of a B24 cage was found. As a demonstration, we attempted to point out the importance of dynamics studies on the future design of sandwich structures.
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330Li, H.-R.; Liu, H.; Tian, X.-X.; Zan, W.-Y.; Mu, Y.-W.; Lu, H.-G.; Li, J.; Wang, Y.-K.; Li, S.-D. Structural transition in metal-centered boron clusters: From tubular molecular rotors Ta@B21 and Ta@B22+ to cage-like endohedral metalloborospherene Ta@B22–. Phys. Chem. Chem. Phys. 2017, 19, 27025– 27030, DOI: 10.1039/C7CP05179DGoogle Scholar330https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVOhtbrP&md5=7b2ba443c1dae6f595efd6d11c055c2eStructural transition in metal-centered boron clusters: from tubular molecular rotors Ta@B21 and Ta@B22+ to cage-like endohedral metalloborospherene Ta@B22-Li, Hai-Ru; Liu, Hui; Tian, Xin-Xin; Zan, Wen-Yan; Mu, Yue-Wen; Lu, Hai-Gang; Li, Jun; Wang, Yue-Kui; Li, Si-DianPhysical Chemistry Chemical Physics (2017), 19 (39), 27025-27030CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Inspired by the recent discovery of the metal-centered tubular mol. rotor Cs B2-Ta@B18- with the record coordination no. of CN = 20 and based on extensive first-principles theory calcns., we present herein the possibility of the largest tubular mol. rotors Cs B3-Ta@B18 (1) and C3v B4-Ta@B18+ (2) and smallest axially chiral endohedral metalloborospherenes D2 Ta@B22- (3 and 3'), unveiling a tubular-to-cage-like structural transition in metal-centered boron clusters at Ta@B22- via effective spherical coordination interactions. The highly stable Ta@B22- (3) as an elegant superatom, which features two equiv. corner-sharing B10 boron double chains interconnected by two B2 units with four equiv. B7 heptagons evenly distributed on the cage surface, conforms to the 18-electron configuration with a bonding pattern of σ + π double delocalization and follows the 2(n + 1)2 electron counting rule for spherical aromaticity (n = 2). Its calcd. adiabatic detachment energy of ADE = 3.88 eV represents the electron affinity of the cage-like neutral D2 Ta@B22 which can be viewed as a superhalogen. The IR, Raman, VCD, and UV-vis spectra of the concerned species are computationally simulated to facilitate their spectral characterizations.
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331Li, H.-R.; Liu, H.; Lu, X.-Q.; Zan, W.-Y.; Tian, X.-X.; Lu, H.-G.; Wu, Y.-B.; Mu, Y.-W.; Li, S.-D. Cage-like Ta@Bqn complexes (n = 23–28, q = −1 – + 3) in 18-electron configurations with the highest coordination number of twenty-eight. Nanoscale 2018, 10, 7451– 7456. DOI: 10.1039/C8NR01087KGoogle Scholar331https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXltFWqsbc%253D&md5=03989b4a840d2c0cd6eef7d395492fa7Cage-like Ta@Bqn complexes (n = 23-28, q = -1-+ 3) in 18-electron configurations with the highest coordination number of twenty-eightLi, Hai-Ru; Liu, Hui; Lu, Xiao-Qin; Zan, Wen-Yan; Tian, Xin-Xin; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Li, Si-DianNanoscale (2018), 10 (16), 7451-7456CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Inspired by recent observations of the highest coordination nos. of CN = 10 in planar wheel-type complexes in D10h Ta@B10- and CN = 20 in double-ring tubular species in D10d Ta@B20- and theor. prediction of the smallest endohedral metalloborospherene D2 Ta@B22- (1) with CN = 22, we present herein the possibility of larger endohedral metalloborospherenes C2 Ta@B23 (2), C2 Ta@B24+ (3), C2v Ta@B24- (4), C1 Ta@B25 (5), D2d Ta@B26+ (6), C2 Ta@B272+ (7), and C2 Ta@B283+ (8) based on extensive first-principles theory investigations. These cage-like Ta@Bqn complexes with B6 pentagonal or B7 hexagonal pyramids on their surface turn out to be the global min. of the systems with CN = 23, 24, 24, 25, 26, 27, and 28, resp., unveiling the highest coordination no. of CN = 28 in spherical environments known in chem. Detailed bonding analyses show that 1-8 as superatoms conform to the 18-electron configuration with a universal σ + π double delocalization bonding pattern. They are effectively stabilized via spd-π coordination interactions between the Ta center and ηn-Bn ligand which match both geometrically and electronically. Such complexes may serve as embryos of novel metal-boride nanomaterials.
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332Rahane, A. B.; Saha, P.; Sukumar, N.; Kumar, V. Smallest Fullerene-like Structures of Boron with Cr, Mo, and W Encapsulation. arXiv:1907.12611 2019.Google ScholarThere is no corresponding record for this reference.
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333Minh Tam, N.; Tan Pham, H.; Van Duong, L.; Phuong Pham-Ho, M.; Tho Nguyen, M. Fullerene-like boron clusters stabilized by an endohedrally doped iron atom: BnFe with n = 14, 16, 18 and 20. Phys. Chem. Chem. Phys. 2015, 17, 3000– 3003, DOI: 10.1039/C4CP04279DGoogle ScholarThere is no corresponding record for this reference.
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334Zhao, L.; Qu, X.; Wang, Y.; Lv, J.; Zhang, L.; Hu, Z.; Gu, G.; Ma, Y. Effects of manganese doping on the structure evolution of small-sized boron clusters. J. Phys.: Condens. Matter 2017, 29, 265401, DOI: 10.1088/1361-648X/aa7190Google Scholar334https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFSjtbjN&md5=aedbf2f1d230bd41df6f068d0876abf4Effects of manganese doping on the structure evolution of small-sized boron clustersZhao, Lingquan; Qu, Xin; Wang, Yanchao; Lv, Jian; Zhang, Lijun; Hu, Ziyu; Gu, Guangrui; Ma, YanmingJournal of Physics: Condensed Matter (2017), 29 (26), 265401/1-265401/7CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Atomic doping of clusters is known as an effective approach to stabilize or modify the structures and properties of resulting doped clusters. We herein report the effect of manganese (Mn) doping on the structure evolution of small-sized boron (B) clusters. The global min. structures of both neutral and charged Mn doped B cluster MnBQn (n = 10-20 and Q = 0, ±1) have been proposed through extensive first-principles swarm-intelligence based structure searches. It is found that Mn doping has significantly modified the grow behaviors of B clusters, leading to two novel structural transitions from planar to tubular and then to cage-like B structures in both neutral and charged species. Half-sandwich-type structures are most favorable for small MnB-/0/+n (n ≤ 13) clusters and gradually transform to Mn-centered double-ring tubular structures at MnB-/0/+16 clusters with superior thermodn. stabilities compared with their neighbors. Most strikingly, endohedral cages become the ground-state structures for larger MnB-/0/+n (n ≥ 19) clusters, among which MnB+20 adopts a highly sym. structure with superior thermodn. stability and a large HOMO-LUMO gap of 4.53 eV. The unique stability of the endohedral MnB+20 cage is attributed to the geometric fit and formation of 18-electron closed-shell configuration. The results significantly advance our understanding about the structure and bonding of B-based clusters and strongly suggest transition-metal doping as a viable route to synthesize intriguing B-based nanomaterials.
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335Wang, Y.; Wu, X.; Zhao, J. Structural evolution and superatoms in molybdenum atom stabilized boron clusters: MoBn (n = 10–24). J. Cluster Sci. 2018, 29, 847– 852, DOI: 10.1007/s10876-018-1369-3Google Scholar335https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmvFKjurc%253D&md5=a1135c202259fef27e7c33590e073516Structural Evolution and Superatoms in Molybdenum Atom Stabilized Boron Clusters: MoBn (n = 10-24)Wang, Yuqing; Wu, Xue; Zhao, JijunJournal of Cluster Science (2018), 29 (5), 847-852CODEN: JCSCEB; ISSN:1040-7278. (Springer)A review. Doping transition metal atom is known as an effective approach to stabilize an at. cluster and modify its structure and electronic properties. We herein report the effect of molybdenum doping on the structural evolution of medium-sized boron clusters. The lowest-energy structures of MoBn (n = 10, 12, 14, 16, 18, 20, 22, 24) clusters are globally searched using genetic algorithm combined with d. functional theory calcns. We found that Mo doping has significantly affected the grow behaviors of Bn clusters, leading to a structural evolution from bowl-like to tubular and finally endohedral cage. The size-dependent binding energy, HOMO-LUMO gap, vertical ionization potential and vertical electron affinity show that MoB12, MoB22 and MoB24 clusters have relatively higher stability and enhanced chem. inertness. More interestingly, the endohedral MoB22 cage is identified as an elegant superatom, which satisfies 18-electron closed shell configuration well.
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336Chen, B.; Sun, W.; Kuang, X.; Lu, C.; Xia, X.; Shi, H.; Gutsev, G. L. Insights into the effects produced by doping of medium-sized boron clusters with ruthenium. Phys. Chem. Chem. Phys. 2018, 20, 30376– 30383, DOI: 10.1039/C8CP05725GGoogle Scholar336https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitF2qurrJ&md5=947d1cbcb4c3c1bc4ee9ac0bc5e6c407Insights into the effects produced by doping of medium-sized boron clusters with rutheniumChen, Bole; Sun, Weiguo; Kuang, Xiaoyu; Lu, Cheng; Xia, Xinxin; Shi, Hongxiao; Gutsev, Gennady L.Physical Chemistry Chemical Physics (2018), 20 (48), 30376-30383CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Modification of properties of boron nanoparticles by doping with transition metals presents a challenging problem because the no. of isomers of both doped and un-doped nanoparticles rapidly increases with the nanoparticle size. Here, we perform a study of neutral and anionic Ru-doped boron clusters RuBn (n = 9-20) using the unbiased CALYPSO structural search method in combination with d. functional theory calcns. Our results show that the neutral RuB9 cluster possesses a perfect planar wheel-like geometrical structure, whereas the RuBn clusters prefer structures of the half-sandwich type in the range of 10 ≤ n ≤ 14, drum-like type in the range of 15 ≤ n ≤ 18 and cage-like structures for larger n values. The geometrical structures of the lowest total energy states of the RuBn- anions are similar to those of the corresponding neutrals, except for RuB10-, RuB11-, RuB14-, RuB15- and RuB20-. The neutral RuB12 and RuB14 clusters are found to exhibit enhanced stability with respect to the rest of the RuBn clusters due to the delocalized bonding between the Ru atom and the boron host.
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337Shao, X.; Qu, X.; Liu, S.; Yang, L.; Yang, J.; Liu, X.; Zhong, X.; Sun, S.; Vaitheeswaran, G.; Lv, J. Structure evolution of chromium-doped boron clusters: Toward the formation of endohedral boron cages. RSC Adv. 2019, 9, 2870– 2876, DOI: 10.1039/C8RA09143AGoogle Scholar337https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1Sjtbo%253D&md5=2239e70786af0be43956a0483992381dStructure evolution of chromium-doped boron clusters: toward the formation of endohedral boron cagesShao, Xuecheng; Qu, Xin; Liu, Siyu; Yang, Lihua; Yang, Jinghai; Liu, Xiaohui; Zhong, Xin; Sun, Shuai; Vaitheeswaran, G.; Lv, JianRSC Advances (2019), 9 (5), 2870-2876CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The electron-deficient nature of boron endows isolated boron clusters with a variety of interesting structural and bonding properties that can be further enriched through metal doping. In the current work, we report the structural and electronic properties of a series of chromium-doped boron clusters. The global min. structures for CrBn clusters with an even no. of n ranging from 8 to 22 are proposed through extensive first-principles swarm-intelligence structure searches. Half-sandwich structures are found to be preferred for CrB8, CrB10, CrB12 and CrB14 clusters and to transform to a drum-like structure at CrB16 cluster. Endohedral cage structures with the Cr atom located at the center are energetically most favorable for CrB20 and CrB22 clusters. Notably, the endohedral CrB20 cage has a high symmetry of D2d and a large HOMO-LUMO gap of 4.38 eV, whose stability is attributed to geometric fit and formation of an 18-electron closed-shell configuration. The current results advance our understanding of the structure and bonding of metal-doped boron clusters.
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338Chen, B. L.; Sun, W. G.; Kuang, X. Y.; Lu, C.; Xia, X. X.; Shi, H. X.; Maroulis, G. Structural stability and evolution of medium-sized tantalum-doped boron clusters: A half-sandwich-structured TaB12– cluster. Inorg. Chem. 2018, 57, 343– 350, DOI: 10.1021/acs.inorgchem.7b02585Google ScholarThere is no corresponding record for this reference.
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339Saha, P.; Rahane, A. B.; Kumar, V.; Sukumar, N. Electronic origin of the stability of transition-metal-doped B14 drum-shaped boron clusters and their assembly into a nanotube. J. Phys. Chem. C 2017, 121, 10728– 10742, DOI: 10.1021/acs.jpcc.6b10838Google Scholar339https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs12rtLg%253D&md5=ae444ba859944ada9b891e76fd6d3ff0Electronic Origin of the Stability of Transition-Metal-Doped B14 Drum-Shaped Boron Clusters and Their Assembly into a NanotubeSaha, Pinaki; Rahane, Amol B.; Kumar, Vijay; Sukumar, N.Journal of Physical Chemistry C (2017), 121 (20), 10728-10742CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We study the stability of drum-shaped transition metal (TM) doped boron clusters, M@Bn with n = 14 and 16, and M = 3d, 4d, and 5d TM atom using ab initio calcns. Our results show that drum-shaped M@B14 clusters are favored for M = Cr, Mn, Fe, Co, and Ni, while in other cases, open conical or bowl shaped structures become more favorable. The isoelectronic Ni@B14 and Co@B14- clusters have large HOMO-LUMO gaps and these are magic clusters. Their stability has been correlated with the occurrence of magic behavior with 24 valence electrons in a disk jellium model while for Fe@B14 case, the drum structure is deformed and the stability occurs at 22 delocalized valence electrons. The bonding nature in these clusters has been studied by analyzing the electron d. at bond and ring crit. points, the Laplacian distribution of the electron d., the electron localization function, the source function, and electron localization-delocalization indexes, all of which suggest two and three-center σ bonding within and between the two B7 rings, resp., and hybridization between the TM d orbitals and the π bonded MOs of the drum. The IR and Raman spectra of these magic clusters show all real frequencies, suggesting the dynamical stability of the drum-shaped structures. There is a low frequency mode assocd. with the M atom. Results of the electronic spectra of the anion clusters are also presented that may help to identify these species in future expts. Further, we discuss the stability of 24 delocalized valence electron systems Mn@B16 anion, Fe@B16, Co@B16 cation, and other related clusters. Assembly of Co@B14 clusters has been shown to stabilize a carbon nanotube-like nanotube of boron with Co at. nanowire inside while a nanotube of boron with triangular network has been obtained with the assembly of Fe@B16 drum-shaped clusters. Both the nanotubes are metallic.
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340Saha, P.; Rahane, A.; Kumar, V.; Sukumar, N. Analysis of the electron density features of small boron clusters and the effects of doping with C, P, Al, Si, and Zn: Magic B7P and B8Si clusters. Phys. Scr. 2016, 91, 053005, DOI: 10.1088/0031-8949/91/5/053005Google Scholar340https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslChs7%252FF&md5=e657372dcf917ec4b458a19820dfd4a6Analysis of the electron density features of small boron clusters and the effects of doping with C, P, Al, Si, and Zn: Magic B7P and B8Si clustersSaha, P.; Rahane, A. B.; Kumar, V.; Sukumar, N.Physica Scripta (2016), 91 (5), 053005/1-053005/15CODEN: PHSTBO; ISSN:0031-8949. (IOP Publishing Ltd.)Boron at. clusters show several interesting and unusual size-dependent features due to the small covalent radius, electron deficiency, and higher coordination no. of boron as compared to carbon. These include aromaticity and a diverse array of structures such as quasi-planar, ring or tubular shaped, and fullerene-like. In the present work, we have analyzed features of the computed electron d. distributions of small boron clusters having up to 11 boron atoms, and investigated the effect of doping with C, P, Al, Si, and Zn atoms on their structural and phys. properties, in order to understand the bonding characteristics and discern trends in bonding and stability. We find that in general there are covalent bonds as well as delocalized charge distribution in these clusters. We assoc. the strong stability of some of these planar/ quasiplanar disk-type clusters with the electronic shell closing with effectively twelve delocalized valence electrons using a disk-shaped jellium model. B9-, B10, B7P, and B8Si, in particular, are found to be exceptional with very large gaps between the HOMO and the LUMO, and these are suggested to be magic clusters.
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341Popov, I. A.; Jian, T.; Lopez, G. V.; Boldyrev, A. I.; Wang, L.-S. Cobalt-centred boron molecular drums with the highest coordination number in the CoB16– cluster. Nat. Commun. 2015, 6, 8654, DOI: 10.1038/ncomms9654Google Scholar341https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1Gks7bL&md5=975ebfb8e3ecf64dae58346b555ce1e6Cobalt-centered boron molecular drums with the highest coordination number in the CoB16- clusterPopov, Ivan A.; Jian, Tian; Lopez, Gary V.; Boldyrev, Alexander I.; Wang, Lai-ShengNature Communications (2015), 6 (), 8654CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)The electron deficiency and strong bonding capacity of boron led to a vast variety of mol. structures in chem. and materials science. Here the authors report the observation of highly sym. cobalt-centered boron drum-like structures of CoB16- (1), characterized by photoelectron spectroscopy and ab initio calcns. The photoelectron spectra display a relatively simple spectral pattern, suggesting a high symmetry structure. Two nearly degenerate isomers with D8d (i) and C4v (ii) symmetries are found computationally to compete for the global min. These drum-like structures consist of two B8 rings sandwiching a cobalt atom, which has the highest coordination no. known heretofore in chem. Doping of boron clusters with a transition metal atom induces an earlier two-dimensional to three-dimensional structural transition. The CoB16- cluster is tested as a building block in a triple-decker sandwich, suggesting a promising route for its realization in the solid state.
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342Jian, T.; Li, W.-L.; Popov, I. A.; Lopez, G. V.; Chen, X.; Boldyrev, A. I.; Li, J.; Wang, L.-S. Manganese-centered tubular boron cluster–MnB16–: A new class of transition-metal molecules. J. Chem. Phys. 2016, 144, 154310, DOI: 10.1063/1.4946796Google Scholar342https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xms1KmtL4%253D&md5=00228d0798fb62cb2300b930703405d2Manganese-centered tubular boron cluster - MnB16-: A new class of transition-metal moleculesJian, Tian; Li, Wan-Lu; Popov, Ivan A.; Lopez, Gary V.; Chen, Xin; Boldyrev, Alexander I.; Li, Jun; Wang, Lai-ShengJournal of Chemical Physics (2016), 144 (15), 154310/1-154310/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report the observation of a manganese-centered tubular boron cluster (MnB16-), which is characterized by photoelectron spectroscopy and ab initio calcns. The relatively simple pattern of the photoelectron spectrum indicates the cluster to be highly sym. Ab initio calcns. show that MnB16- has a Mn-centered tubular structure with C4v symmetry due to first-order Jahn-Teller effect, while neutral MnB16 reduces to C2v symmetry due to second-order Jahn-Teller effect. In MnB16-, two unpaired electrons are obsd., one on the Mn 3dz2 orbital and another on the B16 tube, making it an unusual biradical. Strong covalent bonding is found between the Mn 3d orbitals and the B16 tube, which helps to stabilize the tubular structure. The current result suggests that there may exist a whole class of metal-stabilized tubular boron clusters. These metal-doped boron clusters provide a new bonding modality for transition metals, as well as a new avenue to design boron-based nanomaterials. (c) 2016 American Institute of Physics.
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343Li, W.; Jian, T.; Chen, X.; Li, H.; Chen, T.; Luo, X.; Li, S.; Li, J.; Wang, L. Observation of a metal-centered B2-Ta@B18– tubular molecular rotor and a perfect Ta@B20– boron drum with the record coordination number of twenty. Chem. Commun. 2017, 53, 1587– 1590, DOI: 10.1039/C6CC09570DGoogle Scholar343https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFamu7fJ&md5=767c1c68ff585f02edfbad859e7cbd28Observation of a metal-centered B2-Ta@B18- tubular molecular rotor and a perfect Ta@B20- boron drum with the record coordination number of twentyLi, Wan-Lu; Jian, Tian; Chen, Xin; Li, Hai-Ru; Chen, Teng-Teng; Luo, Xue-Mei; Li, Si-Dian; Li, Jun; Wang, Lai-ShengChemical Communications (Cambridge, United Kingdom) (2017), 53 (10), 1587-1590CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A tubular mol. rotor B2-Ta@B18- (1) and boron drum Ta@B20- (2) with the highest coordination no. of twenty in chem. are obsd. via a joint photoelectron spectroscopy and first-principles theory investigation.
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344Li, W.-L.; Chen, X.; Jian, T.; Chen, T.-T.; Li, J.; Wang, L.-S. From planar boron clusters to borophenes and metalloborophenes. Nat. Rev. Chem. 2017, 1, 0071, DOI: 10.1038/s41570-017-0071Google Scholar344https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtVyksbzL&md5=083b9d32bad110ab0f46a60b54b4f469From planar boron clusters to borophenes and metalloborophenesLi, Wan-Lu; Chen, Xin; Jian, Tian; Chen, Teng-Teng; Li, Jun; Wang, Lai-ShengNature Reviews Chemistry (2017), 1 (10), 0071CODEN: NRCAF7; ISSN:2397-3358. (Nature Research)A review. Elemental boron and its compds. exhibit unusual structures and chem. bonding owing to the electron deficiency of boron. Joint photoelectron spectroscopy and theor. studies over the past decade have revealed that boron clusters possess planar or quasi-planar (2D) structures up to relatively large sizes, laying the foundations for the discovery of boron-based nanostructures. The observation of the 2D B36 cluster provided the first exptl. evidence that extended boron monolayers with hexagonal vacancies were potentially viable and led to the proposition of 'borophenes' - boron analogs of 2D carbon structures such as graphene. Metal-doping can expand the range of potential nanostructures based on boron. Recent studies have shown that the CoB18- and RhB18- clusters possess unprecedented 2D structures, in which the dopant metal atom is part of the 2D boron network. These doped 2D clusters suggest the possibilities of creating metal-doped borophenes with potentially tunable electronic, optical and magnetic properties. Here, we discuss the recent exptl. and theor. advances in 2D boron and doped boron clusters, as well as their implications for metalloborophenes.
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345Romanescu, C.; Galeev, T. R.; Li, W.-L.; Boldyrev, A. I.; Wang, L.-S. Transition-metal-centered monocyclic boron wheel clusters (M@Bn): A new class of aromatic borometallic compounds. Acc. Chem. Res. 2013, 46, 350– 358, DOI: 10.1021/ar300149aGoogle Scholar345https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslOltr7I&md5=bed7702b3865542e2b48d08a274fbf9cTransition-Metal-Centered Monocyclic Boron Wheel Clusters (MBn): A New Class of Aromatic Borometallic CompoundsRomanescu, Constantin; Galeev, Timur R.; Li, Wei-Li; Boldyrev, Alexander I.; Wang, Lai-ShengAccounts of Chemical Research (2013), 46 (2), 350-358CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. Atomic clusters have intermediate properties between that of individual atoms and bulk solids, which provide fertile ground for the discovery of new mols. and novel chem. bonding. In addn., the study of small clusters can help researchers design better nanosystems with specific phys. and chem. properties. From recent exptl. and computational studies, we know that small boron clusters possess planar structures stabilized by electron delocalization both in the σ and π frameworks. An interesting boron cluster is B9-, which has a D8h mol. wheel structure with a single boron atom in the center of a B8 ring. This ring in the D8h-B9- cluster is connected by eight classical two-center, two-electron bonds. In contrast, the cluster's central boron atom is bonded to the peripheral ring through three delocalized σ and three delocalized π bonds. This bonding structure gives the mol. wheel double aromaticity and high electronic stability. The unprecedented structure and bonding pattern in B9- and other planar boron clusters have inspired the designs of similar mol. wheel-type structures. But these mimics instead substitute a heteroatom for the central boron. Through recent expts. in cluster beams, chemists have demonstrated that transition metals can be doped into the center of the planar boron clusters. These new metal-centered monocyclic boron rings have variable ring sizes, MBn and MBn- with n = 8-10. Using size-selected anion photoelectron spectroscopy and ab initio calcns., researchers have characterized these novel borometallic mols. Chemists have proposed a design principle based on σ and π double aromaticity for electronically stable borometallic cluster compds., featuring a highly coordinated transition metal atom centered inside monocyclic boron rings. The central metal atom is coordinatively unsatd. in the direction perpendicular to the mol. plane. Thus, chemists may design appropriate ligands to synthesize the mol. wheels in the bulk. In this Account, we discuss these recent exptl. and theor. advances of this new class of arom. borometallic compds., which contain a highly coordinated central transition metal atom inside a monocyclic boron ring. Through these examples, we show that at. clusters can facilitate the discovery of new structures, new chem. bonding, and possibly new nanostructures with specific, advantageous properties.
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346Zhai, H. J.; Alexandrova, A. N.; Birch, K. A.; Boldyrev, A. I.; Wang, L. S. Hepta-and octacoordinate boron in molecular wheels of eight-and nine-atom boron clusters: Observation and confirmation. Angew. Chem., Int. Ed. 2003, 42, 6004– 6008, DOI: 10.1002/anie.200351874Google Scholar346https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXltlWi&md5=75eff3a71dfa30a2414d5e60b5e0a3e0Hepta- and octacoordinate boron in molecular wheels of eight- and nine-atom boron clusters: Observation and confirmationZhai, Hua-Jin; Alexandrova, Anastassia N.; Birch, K. Alexander; Boldyrev, Alexander I.; Wang, Lai-ShengAngewandte Chemie, International Edition (2003), 42 (48), 6004-6008CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Exptl. and theor. evidence shows that eight- and nine-atom boron clusters are perfectly planar mol. wheels, with a hepta- or octacoordinated central boron atom, resp. (B green). The radii of the miniature mol. wheels are found to be 1.8 and 2.0 Å. Analyses of their chem. bonding reveal that they possess double (σ and π) aromaticity, which is responsible for the wheel structures and the extreme coordination environments.
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347Ito, K.; Pu, Z.; Li, Q.-S.; Schleyer, P. V. R. Cyclic boron clusters enclosing planar hypercoordinate cobalt, iron, and nickel. Inorg. Chem. 2008, 47, 10906– 10910, DOI: 10.1021/ic800993bGoogle Scholar347https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlSqtLfL&md5=b3c06e5de92b5720f5f040c463a5a84fCyclic Boron Clusters Enclosing Planar Hypercoordinate Cobalt, Iron, and NickelIto, Keigo; Pu, Zhifeng; Li, Qian-Shu; Schleyer, Paul von RagueInorganic Chemistry (2008), 47 (23), 10906-10910CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Planar cyclic boron clusters with cobalt, iron, and nickel atoms at their centers - singlet D8h CoB8-, D9h FeB9-, CoB9, and NiB9+ - were computed to be stable min. at the BP86/TZVPP DFT level. Stochastic searches of the singlet and triplet potential energy surfaces show the planar hypercoordinate D8h CoB8- (1) and D9h FeB9- (2) singlet isomers to be the global min. Their double arom. character with 6 π and 10 radial electrons is documented by detailed NICSzz grid and CMO-NICSzz analyses at PW91/TZVPP. These results encourage gas phase investigations of these two exotic anions. Although isoelectronic with D9h FeB9- (2), CoB9 and NiB9+ prefer nonplanar structures.
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348Chen, T.-T.; Li, W.-L.; Bai, H.; Chen, W.-J.; Dong, X.-R.; Li, J.; Wang, L.-S. Re@B8- and Re@B9-: New members of the transition-metal-centered borometallic molecular wheel family. J. Phys. Chem. A 2019, 123, 5317– 5324, DOI: 10.1021/acs.jpca.9b03942Google Scholar348https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtV2mu7fO&md5=ce17c867b4c78712162a9e06069eeff9ReB8- and ReB9-: New Members of the Transition-Metal-Centered Borometallic Molecular Wheel FamilyChen, Teng-Teng; Li, Wan-Lu; Bai, Hui; Chen, Wei-Jia; Dong, Xin-Ran; Li, Jun; Wang, Lai-ShengJournal of Physical Chemistry A (2019), 123 (25), 5317-5324CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Transition-metal-centered monocyclic boron wheel clusters (MBnq) represent a family of interesting borometallic compds. with double aromaticity. A variety of early and late transition metal atoms have been found to form such structures with high symmetries and various Bn ring sizes. Here we report a combined photoelectron spectroscopy and quantum-chem. theor. study of two MBn- clusters from the middle of the transition metal series: ReB8- and ReB9-. Global min. structure searches revealed that ReB8- adopts a pseudo-C8v structure while ReB9- is a perfectly planar D9h mol. wheel. Chem. bonding analyses showed that both clusters exhibit σ and π double aromaticity and obey the electronic design principle for metal-centered borometallic mol. wheels. The central Re atoms are found to possess unusually low oxidn. states of +I in ReB8- and +II in ReB9-, i.e., the Re atom behaves similarly to late transition metal elements (Ru, Fe, Co, Rh, Ir) in the MBn- mol. wheels. These two clusters become new members of the family of transition-metal-centered monocyclic borometallic mol. wheels, which may be viable for chem. syntheses with appropriate ligands.
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349Galeev, T. R.; Romanescu, C.; Li, W.-L.; Wang, L.-S.; Boldyrev, A. I. Observation of the highest coordination number in planar species: Decacoordinated Ta@B10- and Nb@B10- anions. Angew. Chem., Int. Ed. 2012, 51, 2101– 2105, DOI: 10.1002/anie.201107880Google Scholar349https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslCks7o%253D&md5=bacc5848ef010a6ae3f1c67abf8da7baObservation of the Highest Coordination Number in Planar Species: Decacoordinated Ta©B10- and Nb©B10- AnionsGaleev, Timur R.; Romanescu, Constantin; Li, Wei-Li; Wang, Lai-Sheng; Boldyrev, Alexander I.Angewandte Chemie, International Edition (2012), 51 (9), 2101-2105, S2101/1-S2101/6CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors present photoelectron spectroscopy and theor. (ZORA DFT-PBE0/LANDL2DZ and RCCSD(T)) study of Ta©B10- and Nb©B10- cluster anions. Data are presented on photoelectron spectra, vibrational frequencies of neutral TaB10, isomer geometries, HOMOs and LUMOs, and bonding pattern.
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350Li, W.-L.; Ivanov, A. S.; Federic, J.; Romanescu, C.; Cernusak, I.; Boldyrev, A. I.; Wang, L.-S. On the way to the highest coordination number in the planar metal-centred aromatic Ta@B10- cluster: Evolution of the structures of TaBn- (n = 3-8). J. Chem. Phys. 2013, 139, 104312, DOI: 10.1063/1.4820401Google Scholar350https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVeht7nO&md5=29a5fc0fb58ecba7913be33675551172On the way to the highest coordination number in the planar metal-centred aromatic Ta©B10- cluster: Evolution of the structures of TaBn- (n = 3-8)Li, Wei-Li; Ivanov, Alexander S.; Federic, Jozef; Romanescu, Constantin; Cernusak, Ivan; Boldyrev, Alexander I.; Wang, Lai-ShengJournal of Chemical Physics (2013), 139 (10), 104312/1-104312/13CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures and chem. bonding of TaBn- (n = 3-8) clusters are investigated systematically to elucidate the formation of the planar metal-centered arom. borometallic cluster, Ta©B10- (the © sign is used to designate the central position of the doped atom in monocyclic structures in M©Bn-type planar clusters), which was found previously to have the highest coordination no. for a metal atom in a planar geometry. Photoelectron spectroscopy is combined with ab initio calcns. to det. the global min. of the TaBn- clusters. We find that from TaB3- to TaB5- the boron atoms nucleate around the central Ta atom to form fan-like structures. A structural transition occurs at TaB6-, which is found to have a hexagonal structure, but with a boron atom in the center and the Ta atom on the periphery. TaB7- is shown to have a three-dimensional boat-like structure, which can be viewed as a Ta atom coordinated to an elongated B7 cluster from above. The global min. of the TaB8- cluster is found to be pyramidal with the Ta atom interacting with a B8 monocyclic ring. Starting from this structure, addnl. boron atoms simply enlarge the boron ring to form the slightly pyramidal TaB9- cluster and eventually the perfectly planar Ta-centered B10-ring arom. cluster, Ta©B10-. It is shown that boron atoms do not nucleate smoothly around a Ta atom on the way to the decacoordinated Ta©B10- mol. wheel, but rather the competition between B-B interactions and Ta-B interactions dets. the most stable structures of the smaller TaBn- (n = 3-8) clusters. (c) 2013 American Institute of Physics.
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351Pu, Z.; Ito, K.; Schleyer, P. v. R.; Li, Q.-S. Planar hepta-, octa-, nona-, and decacoordinate first row d-block metals enclosed by boron rings. Inorg. Chem. 2009, 48, 10679– 10686, DOI: 10.1021/ic901377hGoogle Scholar351https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1yntLzK&md5=4bf04bb869dcc6b6279da5a2ec662fedPlanar Hepta-, Octa-, Nona-, and Decacoordinate First Row d-Block Metals Enclosed by Boron RingsPu, Zhifeng; Ito, Keigo; Schleyer, Paul v. R.; Li, Qian-ShuInorganic Chemistry (2009), 48 (22), 10679-10686CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Possible planar hypercoordinate mols. with first row d-block metal atoms in the centers of boron rings are explored comprehensively by d.-functional theory (DFT) computations. Many optimized MBn (n = 7, 8, 9, and 10) neutral and charged clusters have local Dnh min., although these may not be the most stable isomers. The larger B9 and B10 rings are versatile in accommodating first row d-block metals, whereas the more compact B8 ring only can enclose smaller transition metals (such as Mn, Fe, and Co) effectively. Delocalized π and radial MOs involving boron are crucial in stabilizing these highly sym. planar hypercoordinate mols. Early and middle transition metal d-orbitals participate in metal-boron covalent bonding, whereas partial ionic bonding is more important for the late d-block elements. Potential energy surface scans established several of these species to have planar hypercoordinate global min.: D8h FeB82- was identified here, and D8h CoB8- and D9h FeB9- were identified in an earlier complementary study.
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352Romanescu, C.; Galeev, T. R.; Li, W.-L.; Boldyrev, A. I.; Wang, L.-S. Aromatic metal-centered monocyclic boron rings: Co@B8- and Ru@B9-. Angew. Chem., Int. Ed. 2011, 50, 9334– 9337, DOI: 10.1002/anie.201104166Google Scholar352https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFSltbvF&md5=3a42a6f0494d91f8db2102c6323131c3Aromatic Metal-Centered Monocyclic Boron Rings: CoB8 and RuB9Romanescu, Constantin; Galeev, Timur R.; Li, Wei-Li; Boldyrev, Alexander I.; Wang, Lai-ShengAngewandte Chemie, International Edition (2011), 50 (40), 9334-9337, S9334/1-S9334/4CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Aromaticity is obsd. in the photoelectron spectra of CoB8 and RuB9. This is confirmed in model calcns. of the electron detachment energies.
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353Li, W.-L.; Romanescu, C.; Galeev, T. R.; Piazza, Z. A.; Boldyrev, A. I.; Wang, L.-S. Transition-metal-centered nine-membered boron rings: M@B9 and M@B9- (M = Rh, Ir). J. Am. Chem. Soc. 2012, 134, 165– 168, DOI: 10.1021/ja209808kGoogle Scholar353https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1SlsrvO&md5=cd0a31e18ba7f04b5d2e69dd5286f921Transition-Metal-Centered Nine-Membered Boron Rings: M©B9 and M©B9- (M = Rh, Ir)Li, Wei-Li; Romanescu, Constantin; Galeev, Timur R.; Piazza, Zachary A.; Boldyrev, Alexander I.; Wang, Lai-ShengJournal of the American Chemical Society (2012), 134 (1), 165-168CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report the observation of two transition-metal-centered nine-atom boron rings, Rh©B9- and Ir©B9-. These two doped-boron clusters are produced in a laser-vaporization supersonic mol. beam and characterized by photoelectron spectroscopy and ab initio calcns. Large HOMO-LUMO gaps are obsd. in the anion photoelectron spectra, suggesting that neutral Rh©B9 and Ir©B9 are highly stable, closed shell species. Theor. calcns. show that Rh©B9 and Ir©B9 are of D9h symmetry. Chem. bonding analyses reveal that these complexes are doubly arom., each with six completely delocalized π and σ electrons, which describe the bonding between the central metal atom and the boron ring. This work establishes firmly the metal-doped B rings as a new class of novel arom. mol. wheels.
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354Kumar, V. Nanosilicon; Elsevier: Amsterdam, 2008.Google ScholarThere is no corresponding record for this reference.
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355Zhu, X.; Zeng, X. C. Structures and stabilities of small silicon clusters: Ab initio molecular-orbital calculations of Si7–Si11. J. Chem. Phys. 2003, 118, 3558– 3570, DOI: 10.1063/1.1535906Google Scholar355https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhtVKju7k%253D&md5=de93d12a411f2f535a4437ddf7f8ab15Structures and stabilities of small silicon clusters: Ab initio molecular-orbital calculations of Si7-Si11Zhu, Xiaolei; Zeng, X. C.Journal of Chemical Physics (2003), 118 (8), 3558-3570CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Ab initio all-electron mol.-orbital calcns. have been carried out to study the structure and relative stability of small silicon clusters (Sin, n = 7-11). A no. of low-energy geometric isomers are optimized at the second-order Moller-Plesset (MP2) MP2/6-31G(d) level. Harmonic vibrational anal. has been performed to assure that the optimized geometries are stable. The total energies of stable isomers are computed at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d) level. The calcd. binding energies per atom at both the MP2/6-31G(d) and CCSD(T)/6-31G(d) levels agree with the expts. For Si7, Si8, and Si10, the lowest-energy structures are the same as those predicted previously from the all-electron optimization at the Hartree-Fock (HF) HF/6-31G(d) level [Raghavachari and Rohlfing, J. Chem. Phys. 89, 2219 (1988)]. For Si9, the lowest-energy isomer is same as that predicted based on d.-functional plane-wave pseudopotential method [Vasiliev, Ogut, and Chelikowsky, Phys. Rev. Lett. 78, 4805 (1997)]. Particular attention has been given to Si11 because several low-energy geometric isomers were found nearly isoenergetic. On the basis of MP2/6-311G(2d)//CCSD(T)/6-311G(2d) calcn., we identified that the C2v isomer, a tricapped trigonal prism with two addnl. caps on side trigonal faces, is most likely the global-min. structure. However, another competitive geometric isomer for the global min. is also found on basis of the MP2/6-311G(2d)//CCSD(T)/6-311G(2d) calcn. Addnl., calcns. of the binding energy and the cluster polarizability offer more insights into relatively strong stability of two magic-no. clusters Si6 and Si10.
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356Götz, D.; Heiles, S.; Johnston, R.; Schäfer, R. Note: Gas phase structures of bare Si8 and Si11 clusters from molecular beam electric deflection experiments. J. Chem. Phys. 2012, 136, 186101, DOI: 10.1063/1.4717708Google Scholar356https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38jks1Sgtw%253D%253D&md5=2570e60bb6a7af957afe2eb063f345d5Note: gas phase structures of bare Si8 and Si11 clusters from molecular beam electric deflection experimentsGotz D A; Heiles S; Johnston R L; Schafer RThe Journal of chemical physics (2012), 136 (18), 186101 ISSN:.There is no expanded citation for this reference.
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357Zhao, J.; Ma, L.; Tian, D.; Xie, R. Fullerene-like cage clusters from non-carbon elements. J. Comput. Theor. Nanosci. 2008, 5, 7– 22Google Scholar357https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhvFaqu7w%253D&md5=adc21fe7dd272474c03c259bd4af8228Fullerene-like cage clusters from non-carbon elementsZhao, Jijun; Ma, Li; Tian, Dongxu; Xie, RuihuaJournal of Computational and Theoretical Nanoscience (2008), 5 (1), 7-22CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)A review of recent exptl. and theor. progresses on the search of the fullerene-like nanocages from non-carbon elements. The systems we discussed include medium-sized silicon clusters with endohedral fullerene structures, transition-metal doped silicon cage clusters, fullerene-like nanocages by group V elements (N, P, As, etc.), clusters with nesting doll structures (e.g., [As @ Ni12As20]3-), heterofullerene nanocages by III-V (BN, AlN, GaAs) and II-VI (ZnO, ZnS, ZnSe) compds., and gold fullerene cages at Au32 and Au50, and so on. The stability of each type of non-carbon fullerene nanocages can be understood by some specific mechanism. These non-carbon fullerenes not only represent novel spheroid mols. with interesting structures and properties, but also are potential building blocks for nanostructured materials and devices.
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358Kumar, V.; Kawazoe, Y. Magic behavior of Si15M and Si16M (M = Cr, Mo, and W) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 65, 073404, DOI: 10.1103/PhysRevB.65.073404Google Scholar358https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XhtFSqs70%253D&md5=f0287d16dc8254fc41619d90e2657b8dMagic behavior of Si15M and Si16M (M=Cr, Mo, and W) clustersKumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2002), 65 (7), 073404/1-073404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio electronic-structure calcns. based on pseudopotential plane-wave method and generalized gradient approxn. for the exchange-correlation energy are performed on SinM (n=14-17 and M=Cr, Mo, and W) clusters. We find an M-encapsulated silicon cage M@Si15 derived from a cubic structure to be the optimally close packed for these elements. There are competing growth modes so that a fullerenelike capped cage of Si16M has the lowest energy leading to their simultaneous magic behavior in agreement with expts. The binding energy, the highest occupied-LUMO gap and the embedding energy of M are large, giving rise to their strong stability and complete quenching of the magnetic moment of M. Similar cubic M@Si15 structures are predicted for M=Ti, Hf, Zr, Ru, and Os.
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359Kumar, V.; Majumder, C.; Kawazoe, Y. M@Si16, M = Ti, Zr, Hf: π conjugation, ionization potentials and electron affinities. Chem. Phys. Lett. 2002, 363, 319– 322, DOI: 10.1016/S0009-2614(02)01184-3Google Scholar359https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmvVCms7c%253D&md5=082f853747280d9b29f69938f28cbc0fM@Si16, M = Ti, Zr, Hf: π conjugation, ionization potentials and electron affinitiesKumar, Vijay; Majumder, C.; Kawazoe, YoshiyukiChemical Physics Letters (2002), 363 (3,4), 319-322CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The bonding nature in the fullerene and Frank-Kasper (FK) polyhedral isomers of M@Si16, M = Ti, Zr, and Hf clusters has been studied using ab initio calcns. based on the Gaussian 98 program as well as a ultrasoft pseudopotential plane wave method. The fullerene isomer is found to have double bonds between some Si atoms such that each silicon has two single bonds and a double bond on the cage of these endohedral clusters very similar to C60. There is a mixed sp2-sp3 bonding character between Si atoms and only a small charge transfer from M to the Si cage. The sp2 bonding gives rise to π conjugation. On the other hand in the FK isomer, about three electrons are transferred from M to the Si cage making the bonding nature in this isomer quite different. The ionization potentials of these clusters are large (≈7.5 eV) similar to C60 and the electron affinities are small that make these clusters behave like superatoms.
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360Kumar, V.; Kawazoe, Y. Hydrogenated silicon fullerenes: Effects of H on the stability of metal-encapsulated silicon clusters. Phys. Rev. Lett. 2003, 90, 055502, DOI: 10.1103/PhysRevLett.90.055502Google Scholar360https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXht1ygsLw%253D&md5=c3ad0e9ab0b64f1377bfd4b33b970204Hydrogenated Silicon Fullerenes: Effects of H on the Stability of Metal-Encapsulated Silicon ClustersKumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2003), 90 (5), 055502/1-055502/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Ab initio calcns. of H interaction on Si12M, Si18M2 (M=Cr, Mo, and W), and Zr@Si16 fullerene (f) show relatively weak binding of H in agreement with exptl. results of H free Si12M and Si18M2 clusters. Adsorption of H enhances sp3 bonding between the Si atoms, weakens the M-Si cage interactions, and leads to distortions in the cages. Si12CrH12 has 4μB magnetic moment in contrast to zero for Si12Cr. Removal of the M atom leads to stable empty cages of Si12H12, f-Si16H16, and f-Si20H20 with large highest occupied-LUMO gaps of 2.5-3.0 eV, making them attractive for optoelectronic applications.
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361Kumar, V.; Briere, T. M.; Kawazoe, Y. Ab initio calculations of electronic structures, polarizabilities, Raman and infrared spectra, optical gaps, and absorption spectra of M@Si16 (M = Ti and Zr) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 155412, DOI: 10.1103/PhysRevB.68.155412Google Scholar361https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVSrurc%253D&md5=4a5af3d897b7570d6ea400d177ad820fAb initio calculations of electronic structures, polarizabilities, Raman and infrared spectra, optical gaps, and absorption spectra of M@Si16 (M=Ti and Zr) clustersKumar, Vijay; Briere, Tina M.; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2003), 68 (15), 155412/1-155412/9CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio calcns. were performed using d.-functional theory with the B3PW91 hybrid exchange-correlation functional and the Gaussian method to obtain the electronic and vibrational properties of the fullerene (f) and Frank-Kasper (FK) isomers of the metal-encapsulated Si clusters M@Si16, M = Ti and Zr. The electron affinities of the two isomers differ significantly and the authors' result for FK-Ti@Si16 is in good agreement with recent expts. The Raman and IR vibrational spectra of the f and FK isomers show marked differences, due to their distinct bonding natures and structural features, that can be used unambiguously to identify the structures of these clusters exptl. The polarizabilities, however, have similar values and lie above the bulk limit of Si. The optical gaps and absorption spectra were calcd. using time-dependent d.-functional theory. The lowest electronic excitation for the FK isomer lies in the deep blue region, while the one for the f isomer lies in the red region, making them attractive for optoelectronic applications.
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362Kawamura, H.; Kumar, V.; Kawazoe, Y. Growth, magic behavior, and electronic and vibrational properties of Cr-doped Si clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 245433, DOI: 10.1103/PhysRevB.70.245433Google Scholar362https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXislOqsQ%253D%253D&md5=18ac85e54e947b6e5ab0ee9b5369c788Growth, magic behavior, and electronic and vibrational properties of Cr-doped Si clustersKawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 70 (24), 245433/1-245433/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Silicon clusters doped with a Cr atom have been studied using ab initio plane-wave ultrasoft pseudopotential and Gaussian methods. The most stable structures and magic clusters have been detd. for SinCr (n=8-17) starting from many initial configurations. Our results show that for n=8-11 the no. of Si atoms is not enough to surround a Cr atom fully and therefore the structures of these clusters are basket type in which the Cr atom has a bare part. A cage structure is formed for n = 12 Cr@i12 and Cr@i15 show magic behavior. Among the charged clusters, anion of Cr@i12 and cation of Cr@i13 have high stability. The ionization potentials and electron affinities have been calcd. The dynamical stability of clusters is studied from vibrational calcns. The results of Raman activities and IR intensities are presented for selected clusters. These can be used to identify the structures from expts. The bonding nature in Cr@in clusters is found to change depending on the structure even when the cluster size is the same.
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363Sun, Q.; Wang, Q.; Briere, T.; Kumar, V.; Kawazoe, Y.; Jena, P. First-principles calculations of metal stabilized Si20 cages. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 65, 235417, DOI: 10.1103/PhysRevB.65.235417Google Scholar363https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XltlSkt7k%253D&md5=4e9a26b457d122454b35d680eea99109First-principles calculations of metal stabilized Si20 cagesSun, Q.; Wang, Q.; Briere, T. M.; Kumar, V.; Kawazoe, Y.; Jena, P.Physical Review B: Condensed Matter and Materials Physics (2002), 65 (23), 235417/1-235417/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)It is well known that sp2 bonding in carbon can result in stable cage structures, but pure Si clusters with similar cage structures are unstable. Using first-principles B3LYP-DFT calcns., we show that a dodecahedral cage of silicon can be stabilized dynamically as well as energetically by doping with Ba, Sr, Ca, Zr, and Pb atoms to create structures of silicon similar to that of the smallest carbon fullerene. The stability and bonding in such cages shed light on Si clathrates in which Si20 is the basic building block of the structure. Moreover, the charge distributions and HOMO-LUMO gaps for these cage structures can be tuned by changing the metal atom. This allows addnl. freedom for the design of nanomaterials involving Si.
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364Kawamura, H.; Kumar, V.; Kawazoe, Y. Growth and magic behavior of metal encapsulated silicon clusters. Mater. Trans. 2004, 45, 1429– 1432, DOI: 10.2320/matertrans.45.1429Google Scholar364https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXkvFyjtrs%253D&md5=94682891455ed2b7c0e056a541418243Growth and magic behavior of metal encapsulated silicon clustersKawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiMaterials Transactions (2004), 45 (5), 1429-1432CODEN: MTARCE; ISSN:1345-9678. (Japan Institute of Metals)Metal encapsulated silicon clusters M@Sin (M = Ti and Cr and n = 8-16) were studied using DFT ab-initio ultrasoft pseudopotential method. Several structures for each cluster were optimized to obtain the lowest energy isomers. Cage structures begin to form at size n=12 for Cr@Sin and n=13 for Ti@Sin. For Ti@Sin our results are in excellent agreement with the available exptl. results. For smaller n, metal doped silicon clusters have basket structures which have the lowest energy. The bonding nature in these clusters is discussed from the electronic charge distribution.
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365Kawamura, H.; Kumar, V.; Kawazoe, Y. Growth behavior of metal-doped silicon clusters SinM (M = Ti, Zr, Hf; n = 8–16). Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 075423, DOI: 10.1103/PhysRevB.71.075423Google Scholar365https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXitVKhsLk%253D&md5=c1f29675e411c7545c1cf6b6bf3d3e00Growth behavior of metal-doped silicon clusters SinM (M = Ti,Zr,Hf; n = 8-16)Kawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (7), 075423/1-075423/12CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The growth behavior of metal-doped silicon clusters MSin, M = Ti, Zr, and Hf and n = 8-16 is studied using an ab initio ultrasoft pseudopotential plane wave method and the generalized gradient approxn. for the exchange-correlation energy. For n = 8-12, we find basketlike open structures to be most favorable, while for n = 13-16, the metal atom is completely surrounded by silicon atoms. These results are in excellent agreement with the obsd. reactivity of these clusters. Our results suggest continuous aggregation until n = 16, which is the optimal cage for the metal-encapsulated silicon clusters with these elements. Further calcns. have been done on cation and anion clusters using the Gaussian method. The calcd. electron affinities agree well with exptl. results in the range of n = 12-16 while the calcd. values for smaller clusters are higher. Raman activity and IR spectra have been calcd. for selected clusters. These could help in the identification of the structures of these clusters from expts.
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366Singh, A. K.; Kumar, V.; Kawazoe, Y. Stabilizing the silicon fullerene Si20 by thorium encapsulation. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 115429, DOI: 10.1103/PhysRevB.71.115429Google Scholar366https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXivFehsrc%253D&md5=a4c20bd47a7efadfb22d8c81c0b77eaaStabilizing the silicon fullerene Si20 by thorium encapsulationSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (11), 115429/1-115429/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We show using ab initio electronic structure calcns. that the dodecahedral fullerene of silicon Si20 is stabilized by thorium encapsulation. Thorium is found to be the only element in the Periodic Table that stabilizes this fullerene with icosahedral symmetry in the neutral state. The preference for sp3 bonding in silicon makes it an optimal cage with all pentagonal faces in contrast to carbon for which C20 is difficult to stabilize. Similar to C60, this is the highest symmetry cluster of silicon and should be abundant. It could lead to the possibilities of novel new phases and derivs. of silicon.
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367Kumar, V.; Singh, A. K.; Kawazoe, Y. Charged and magnetic fullerenes of silicon by metal encapsulation: Predictions from ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 125411, DOI: 10.1103/PhysRevB.74.125411Google Scholar367https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVyksrzI&md5=ec4d3ea112031d5caa40fcb5ba362d1fCharged and magnetic fullerenes of silicon by metal encapsulation: Predictions from ab initio calculationsKumar, Vijay; Singh, Abhishek Kumar; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2006), 74 (12), 125411/1-125411/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using ab initio calcns., the encapsulation of Y, La, and Ac metal (M) atom stabilizes the dodecahedral fullerene anion M@Si20- in the icosahedral symmetry. Similar to C60, it is the ideal cage of silicon and the largest that can be stabilized by an M atom. Doping of other rare earths is further shown to stabilize magnetic dodecahedral fullerenes La@Si20, Sm@Si20, Pu@Si20, and Tm@Si20 with 1 μB, 4 μB, 4 μB, and 3 μB spin magnetic moments, resp., in contrast to most previous studies on M-encapsulated Si clusters in which the magnetic moment is completely quenched. The highest spin magnetic moment of 7 μB is achieved for Gd@Si20- with half-filled 4f states. The orbital magnetic moment is also calcd. and it is ∼1 μB in most cases. Neutral M@Si20 (M = Y, La, Ac, and Gd) behaves like superhalogen and interaction with a noble or alkali metal atom leads to salt like behavior. These findings could pave way for the realization of silicon fullerenes by doping of several elements.
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368Hongo, K.; Kumar, V.; Kawazoe, Y.; Yasuhara, H. Quantum monte carlo study of electron correlation in chromium-doped silicon cluster Cr@Si12. Mater. Trans. 2006, 47, 2617– 2619, DOI: 10.2320/matertrans.47.2617Google Scholar368https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntVCisw%253D%253D&md5=777730390d862c621e133efcfdd9de08Quantum monte carlo study of electron correlation in chromium-doped silicon cluster Cr@Si12Hongo, Kenta; Kumar, Vijay; Kawazoe, Yoshiyuki; Yasuhara, HiroshiMaterials Transactions (2006), 47 (11), 2617-2619CODEN: MTARCE; ISSN:1345-9678. (Japan Institute of Metals)Electron correlation in chromium-doped silicon cluster (Cr@Si12) in its neutral, pos., and neg. charged states with different nuclear configurations is investigated by means of quantum Monte Carlo methods. The correlation energy per electron is independent of whether the state is charged or not and about-1 eV for each of these three states. The total binding energy of the neutral state per atom is 3.5 eV, which is divided into the Hartree-Fock contribution nearly equal to 1.2 eV and the correlation contribution as large as 2.3 eV. In the Hartree-Fock approxn., the ionization energy is 6.9 eV and the electron affinity is 2.7 eV. Correlation increases the ionization energy by 1.7 eV and the electron affinity by 1.4 eV.
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369Kumar, V. Alchemy at the nanoscale: Magic heteroatom clusters and assemblies. Comput. Mater. Sci. 2006, 36, 1– 11, DOI: 10.1016/j.commatsci.2005.06.004Google Scholar369https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XislWmsL4%253D&md5=d50b55a67685d83ad35019978600397cAlchemy at the nanoscale: magic heteroatom clusters and assembliesKumar, VijayComputational Materials Science (2006), 36 (1-2), 1-11CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)A review. Mixing of elements at the nanoscale can offer exciting possibilities of novel materials with compns., structures, and properties quite different from those known in bulk. Ab initio calcns. are expected to play a major role in understanding their properties as well as in predicting and designing such materials. Here, we briefly review recent progress where encapsulation of an atom A or a group of atoms G or exohedral atom(s) have been used to stabilize cage-like nanoclusters/fullerenes of material B. The encapsulation enhances the stability of nanoclusters and can lead to striking preference for a specific size. This can facilitate the design and prodn. of nanoclusters with specific properties in high abundances and the development of assemblies of such species. We discuss the electronic origin of the stability of such species as well as assemblies of size selected nanoparticles that have led to the formation of nanowires and nanotubes. Several examples of such clusters of semiconductors and metals are presented.
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370Jaiswal, S.; Babar, V. P.; Kumar, V. Growth behavior, electronic structure, and vibrational properties of SinY anion clusters (n = 4–20): Metal atom as linker and endohedral dopant. Phys. Rev. B: Condens. Matter Mater. Phys. 2013, 88, 085412, DOI: 10.1103/PhysRevB.88.085412Google Scholar370https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsF2kt7vF&md5=e27c6734f0c6ea8870a2cda7337d16f6Growth behavior, electronic structure, and vibrational properties of SinY anion clusters (n = 4-20): metal atom as linker and endohedral dopantJaiswal, S.; Babar, Vasudeo P.; Kumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2013), 88 (8), 085412/1-085412/14CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We report results of ab initio calcns. on Y-doped anion Sin clusters with n = 4-20. Our results suggest two growth behaviors in the intermediate range of n = 8 and 20: (1) There is the formation of linked clusters in which a metal atom links two subclusters and (2) where silicon atoms form a cage structure and the metal atom is inside the cage to produce endohedral cages of silicon clusters. The cluster structures have been identified by comparing the calcd. spectra of the electronic states with the photoemission spectra on anion clusters. Our results suggest that in some cases a higher energy isomer may be present in expts. We report the calcns. of the IR and Raman spectra as well as the dipole moments, electron affinity, and polarizability that could provide other ways of identifying the growth behavior in these clusters.
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371Khanna, S.; Rao, B.; Jena, P. Magic numbers in metallo-inorganic clusters: Chromium encapsulated in silicon cages. Phys. Rev. Lett. 2002, 89, 016803, DOI: 10.1103/PhysRevLett.89.016803Google Scholar371https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XkslCitb4%253D&md5=b884a566eb5ad69cc920df7a672258c1Magic numbers in metallo-inorganic clusters: chromium encapsulated in silicon cagesKhanna, S. N.; Rao, B. K.; Jena, P.Physical Review Letters (2002), 89 (1), 016803/1-016803/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)A systematic DFT-GGA study is presented of the equil. geometries and total energies of Sin and Cr@Sin clusters (n=11-14); Cr@Si12 is more stable than the others. The origin of this enhanced stability is consistent with the 18-electron sum rule commonly used in the synthesis of stable chem. complexes, and may provide a criterion for a systematic search of magic nos. in metallo-inorg. clusters. The 6μB magnetic moment of the caged Cr atom, the largest among the 3d transition metal atoms, is completely quenched. This effect of caging on the properties of transition metal atoms may lead to the synthesis of novel cluster based materials.
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372Xiao, C.; Hagelberg, F.; Lester, W. A., Jr Geometric, energetic, and bonding properties of neutral and charged copper-doped silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 66, 075425, DOI: 10.1103/PhysRevB.66.075425Google Scholar372https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XntVWju7o%253D&md5=974424f95c5f20a22ed29adccabc002aGeometric, energetic, and bonding properties of neutral and charged copper-doped silicon clustersXiao, Chuanyun; Hagelberg, Frank; Lester, William A., Jr.Physical Review B: Condensed Matter and Materials Physics (2002), 66 (7), 075425/1-075425/23CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The authors studied properties of CuSin clusters (n = 4, 6, 8, 10, and 12) in neutral and charged states using the B3LYP-DFT method. The Sin frameworks in most isomers of CuSin adopt the geometries of the ground-state or low-lying isomers of Sin or Sin+1, with Cu at various substitutional or adsorption sites. Several cage-like structures with Cu at the center site were found for CuSi10 and CuSi12. A hexagonal double-chair structure with Cu at the center, which bears a similarity to the structure of a regular hexagonal prism recently reported for WSi12+ [H. Hiura et al., Phys. Rev. Lett. 86, 1733 (2001)], was identified as the best candidate for the ground state of CuSi12. The Cu-Si bond in CuSin is strong for the substitutional and the center-site structures, but weak for the adsorption structures where charge transfer and resulting ionic interaction play a more important role. The Cu atom reveals a similar bonding character to the replaced Si atom in the substitutional structures except for CuSi12, where the Cu atom both in the substitutional and in the center-site structures forms multicenter bonds with as many as nine (substitutional) to 12 (center-site) Si atoms. Various energetic properties, including binding and dissocn. energies, ionization potentials, electron affinities, and vertical detachment energies are reported for CuSin.
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373Han, J.-G.; Xiao, C.; Hagelberg, F. Geometric and electronic structure of WSiN (N = 1–6, 12) clusters. Struct. Chem. 2002, 13, 173– 191, DOI: 10.1023/A:1015712717153Google Scholar373https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XksFCju7c%253D&md5=b5fc18abb0b4a87737ec7df79eb73f20Geometric and Electronic Structure of WSiN(N = 1-6, 12) ClustersHan, Ju-Guang; Xiao, Chuanyun; Hagelberg, FrankStructural Chemistry (2002), 13 (2), 173-191CODEN: STCHES; ISSN:1040-0400. (Kluwer Academic/Plenum Publishers)Geometry optimizations of WSiN (n = 1-6, 12) clusters were performed using the B3LYP/ LanL2DZ method for a sequence of different spin states, changing from spin singlet to spin septet conditions. The resulting equil. structures are discussed in relation to internal charge transfer and magnetic properties. The W impurity in the SiN environment generally acts as an electron acceptor. However, the charge on the W atom, as obtained by natural population anal., can be sensitively tuned through the variation of the spin constraint from S = 0 to S = 3. The resulting geometries of WSin (N = 3-6) are compared with the known ground state structures of SiN+1 (N = 3-6); substitutional geometries are identified for N = 3 and N = 5. The nonzero spin states of WSiN display different patterns of magnetic order, corresponding to uniform and to alternating at. spin orientations within the cluster. Highly compact Oh and D6h structures were identified as stable geometries of WSi6 and of the exptl. detected unit WSi12, resp. Comparison is made with the cluster series MoSiN(N = 1-6) and CuSiN(N = 1-6,12).
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374Miyazaki, T.; Hiura, H.; Kanayama, T. Topology and energetics of metal-encapsulating Si fullerenelike cage clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 66, 121403, DOI: 10.1103/PhysRevB.66.121403Google Scholar374https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvVahtbo%253D&md5=8725646a1420b89d1b71e05070cb6c8eTopology and energetics of metal-encapsulating Si fullerenelike cage clustersMiyazaki, Takehide; Hiura, Hidefumi; Kanayama, ToshihikoPhysical Review B: Condensed Matter and Materials Physics (2002), 66 (12), 121403/1-121403/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)On the basis of a topol. discussion as well as an ab initio calcn., we show that it is possible to construct a fullerenelike Si cage by doping a transition metal atom in the cage center. The cage is a simple 3-polytope which maximizes the no. of its inner diagonals close to the metal atom. Our topol. argument also reveals how closely the structure of the fullerenelike Si cages studied is related to that of fullerenes themselves.
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375Gueorguiev, G.; Pacheco, J. Silicon and metal nanotemplates: Size and species dependence of structural and electronic properties. J. Chem. Phys. 2003, 119, 10313– 10317, DOI: 10.1063/1.1617977Google Scholar375https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXos1Sjtro%253D&md5=9d85abf47879be7a775108db81b0083fSilicon and metal nanotemplates: size and species dependence of structural and electronic propertiesGueorguiev, G. K.; Pacheco, J. M.Journal of Chemical Physics (2003), 119 (19), 10313-10317CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We utilize first-principles computer simulations to study the dependence on size (n) and species (M) of structural and electronic properties of clusters with stoichiometry M Sin. We investigate a total of 168 clusters comprising from 1 to 14 silicon atoms together with one transition metal atom among 12 different elements. It is found that all elements exhibit a very similar size-dependence for the cohesive energy, in which clusters with n=7, 12 appear as local maxima, with shapes which are found to be essentially independent of the transition metal atom. It is also found that the electronic properties of structurally equiv. clusters depend sensitively on the transition metal atom involved, providing the means to tailor specific properties when designing cluster assembled materials.
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376Lu, J.; Nagase, S. Structural and electronic properties of metal-encapsulated silicon clusters in a large size range. Phys. Rev. Lett. 2003, 90, 115506, DOI: 10.1103/PhysRevLett.90.115506Google Scholar376https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXitlelt70%253D&md5=90973920b3456bf4df6bd12580d85295Structural and Electronic Properties of Metal-Encapsulated Silicon Clusters in a Large Size RangeLu, Jing; Nagase, ShigeruPhysical Review Letters (2003), 90 (11), 115506/1-115506/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Structural and electronic properties of metal-doped silicon clusters MSin (M = W, Zr, Os, Pt, Co, etc.) in a large size range of 8 ≤ n≤ 20 are investigated via ab initio calcns. Different from a recent exptl. suggestion that the metal atom is endohedral in MSin, we reveal that the formation of endohedral structure strongly depends on the size of the Sin cluster. Two novel structures of the chem. stable endohedral species are manifested. The suitable M@Sin building blocks of self-assembly materials vary in the range of 10 ≤ n ≤16. The thermodynamical magic nos. are found to coincide with the chem. magic nos. for five clusters.
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377Khanna, S.; Rao, B.; Jena, P.; Nayak, S. Stability and magnetic properties of iron atoms encapsulated in Si clusters. Chem. Phys. Lett. 2003, 373, 433– 438, DOI: 10.1016/S0009-2614(03)00511-6Google Scholar377https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXktFGnur0%253D&md5=6d1cf00e67dd1740fbab4c50a90e6498Stability and magnetic properties of iron atoms encapsulated in Si clustersKhanna, S. N.; Rao, B. K.; Jena, P.; Nayak, S. K.Chemical Physics Letters (2003), 373 (5,6), 433-438CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Equil. geometries, total energies, ionization potentials, electronic structure, and magnetic properties of Fe encapsulated Sin clusters contg. 9-11 Si atoms were calcd. using the d. functional theory and generalized gradient approxn. for exchange and correlation. The geometries of bare Sin clusters are substantially modified due to Fe, which occupies an endohedral position. The Si10Fe cluster is more stable than its neighbors even though not all Si atoms are 4-fold coordinated. The stability of Si10Fe, however, is consistent with the 18-electron rule. The magnetic moment of Fe is quenched in all the clusters studied.
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378Miyazaki, T.; Hiura, H.; Kanayama, T. Electronic properties of transition-metal-atom doped Si cage clusters. Eur. Phys. J. D 2003, 24, 241– 244, DOI: 10.1140/epjd/e2003-00121-xGoogle Scholar378https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXntFehtrk%253D&md5=15bb1951ad9a70560c7fc3b46fd57204Electronic properties of transition-metal-atom doped Si cage clustersMiyazaki, T.; Hiura, H.; Kanayama, T.European Physical Journal D: Atomic, Molecular and Optical Physics (2003), 24 (1-3), 241-244CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)We present a d.-functional study of electronic structures of convex-caged Si clusters doped with transition-metal (TM) atoms. First, we show the reason for their peculiar geometries in terms of interplay among the electron orbitals of Si and TM atoms. Then we describe the potential ability of the clusters to serve as charge sources to other objects such as Si crystal surfaces.
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379Hagelberg, F.; Xiao, C.; Lester, W. A., Jr Cagelike Si12 clusters with endohedral Cu, Mo, and W metal atom impurities. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 67, 035426, DOI: 10.1103/PhysRevB.67.035426Google Scholar379https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXht1yju78%253D&md5=74d63c4a12c2930016e479e91fb7f710Cagelike Si12 clusters with endohedral Cu, Mo, and W metal atom impuritiesHagelberg, F.; Xiao, C.; Lester, William A.Physical Review B: Condensed Matter and Materials Physics (2003), 67 (3), 035426/1-035426/9CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)In a recent series of mass-spectrometric ion trap measurements [H. Hiura et al., Phys. Rev. Lett. 86, 1733 (2001)], the formation of silicon clusters with endohedral transition-metal impurities was obsd. Particular stability was assigned to the exptl. detected species WSi12+, which has been shown by ab initio geometry optimization to adopt the shape of a regular hexagonal Si12 prism with the W atom in the center. A similar geometry-namely, a Si12 double-chair structure surrounding the metal atom impurity-has emerged from our extensive investigations of silicon clusters in combination with a Cu atom (CuSiN) as the likely ground-state structure of CuSi12. These results suggest the systematic importance of Si12 cages derived from regular structures with D6h geometry for the architecture of silicon clusters contg. metal atom impurities. In the present comparative study, we discuss the salient features of endohedral MSi12 clusters with M = Cu, Mo, W, as well as several cationic and anionic species of these systems, with regard to their geometric and electronic structure. The interaction between the Si12 cage and the enclosed metal impurity is characterized as strongly delocalized bonding for M=Mo, W, while Cu tends to form directed bonds with selected atoms of the cage. Linear extension of the MSi12 (Me=Mo,W) cells along their principal axes leads to units of the form M2Si18.
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380Mpourmpakis, G.; Froudakis, G. E.; Andriotis, A. N.; Menon, M. Fe encapsulation by silicon clusters: Ab initio electronic structure calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 125407, DOI: 10.1103/PhysRevB.68.125407Google Scholar380https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXotVOnur8%253D&md5=66e12a8eda95cd5c7cd212dfb276e7c2Fe encapsulation by silicon clusters: Ab initio electronic structure calculationsMpourmpakis, Giannis; Froudakis, George E.; Andriotis, Antonis N.; Menon, MadhuPhysical Review B: Condensed Matter and Materials Physics (2003), 68 (12), 125407/1-125407/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio electronic structure calcns. based on d. functional theory are performed for SinFe clusters to det. stable structures. These clusters can form the building block for Fe-encapsulated Si-nanotubes. The Si10Fe and Si12Fe clusters are found to be very stable, exhibiting large charge transfer, and can lead to Si-based nanotubes of the types Si5nFen-1 and Si6nFen-1, resp. The effect of Si encapsulation on the magnetic properties of the Fe atom is also investigated.
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381Sen, P.; Mitas, L. Electronic structure and ground states of transition metals encapsulated in a Si12 hexagonal prism cage. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 155404, DOI: 10.1103/PhysRevB.68.155404Google Scholar381https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVSrtLk%253D&md5=2cab5df5739c4713d903d6923bb1433dElectronic structure and ground states of transition metals encapsulated in a Si12 hexagonal prism cageSen, Prasenjit; Mitas, LubosPhysical Review B: Condensed Matter and Materials Physics (2003), 68 (15), 155404/1-155404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We report on a computational study of the electronic structure of recently discovered clusters with an encapsulated transition metal (TM) atom in a Si12 hexagonal prism cage. The cage geometry is remarkably stable regardless of the type of doping TM atom from 3d, 4d, and 5d series. We predict and quantify the stability for several other TM dopings besides the exptl. obsd. ones. The multiplicity of the ground states can be "tuned" between singlets and triplets by varying the type of TM atom (even no. of electrons), while they are doublets for odd no. of electrons. We also explore the possibility of forming solids with hexagonal structure from selected clusters.
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382Guo, P.; Ren, Z.-Y.; Wang, F.; Bian, J.; Han, J.-G.; Wang, G.-H. Structural and electronic properties of TaSin (n = 1–13) clusters: A relativistic density functional investigation. J. Chem. Phys. 2004, 121, 12265– 12275, DOI: 10.1063/1.1809609Google Scholar382https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFSnsrzM&md5=158dc89c9ce63429813244e6cb4cb7edStructural and electronic properties of TaSin (n=1-13) clusters: A relativistic density functional investigationGuo, Ping; Ren, Zhao-Yu; Wang, Fan; Bian, Jiang; Han, Ju-Guang; Wang, Guang-HouJournal of Chemical Physics (2004), 121 (24), 12265-12275CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The TaSin (n = 1-13) clusters with doublet, quartet, and sextet spin configurations have been systematically investigated by a relativistic d. functional theory with the generalized gradient approxn. available in Amsterdam d. functional program. The total bonding energies, equil. geometries, Mulliken populations as well as Hirshfeld charges of TaSin (n = 1-13) clusters are calcd. and presented. The emphasis on the stabilities and electronic properties is discussed. The most stable structures of the small TaSin (n = 1-6) clusters and the evolutional rule of low-lying geometries of the larger TaSin (n = 7-13) clusters are obtained. Theor. results indicate that the most stable structure of TaSin (n = 1-6) clusters keeps the similar framework as the most stable structure of Sin+1 clusters except for TaSi3 cluster. The Ta atom in the lowest-energy TaSin (n = 1-13) isomers occupies a gradual sinking site, and the site moves from convex, to flatness, and to concave with the no. of Si atom varying from 1 to 13. When n = 12, the Ta atom in TaSi12 cluster completely falls into the center of the Si frame, and a cagelike TaSi12 geometry is formed. Meanwhile, the net Mulliken and Hirsheld populations of the Ta atom in the TaSin (n = 1-13) clusters vary from pos. to neg., manifesting that the charges in TaSin (n ≥ 12) clusters transfer from Si atoms to Ta atom. Addnl., the contribution of Si-Si and Si-Ta interactions to the stability of TaSin clusters is briefly discussed. Furthermore, the investigations on at. averaged binding energies and fragmentation energies show that the TaSin (n = 2,3,5,7,10,11,12) clusters have enhanced stabilities. Compared with pure silicon clusters, a universal narrowing of HOMO-LUMO gap in TaSin clusters is found.
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383Andriotis, A. N.; Mpourmpakis, G.; Froudakis, G. E.; Menon, M. Magnetic enhancement and magnetic reduction in binary clusters of transition metal atoms. J. Chem. Phys. 2004, 120, 11901– 11904, DOI: 10.1063/1.1752878Google Scholar383https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXkvVantrc%253D&md5=fb17bb75316172a94ed0864958b75034Magnetic enhancement and magnetic reduction in binary clusters of transition metal atomsAndriotis, Antonis N.; Mpourmpakis, Giannis; Froudakis, George E.; Menon, MadhuJournal of Chemical Physics (2004), 120 (24), 11901-11904CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Electronic and magnetic properties of small binary clusters contg. one or two transition metal atoms are investigated using ab initio calcns. with a view to explain the exptl. obsd. magnetic enhancement/redn. in these systems. As the present investigations do not rely on spin-orbit effects, our results reveal the enhancement or redn. in the magnetic moment to depend on two main factors; namely geometry and, most importantly, the d-band filling. The results can be used as a guide in the exptl. synthesis of high d. magnetic grains.
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384Han, J.-G.; Ren, Z.-Y.; Lu, B.-Z. Geometries and stabilities of Re-doped Sin (n = 1– 12) clusters: A density functional investigation. J. Phys. Chem. A 2004, 108, 5100– 5110, DOI: 10.1021/jp031006oGoogle Scholar384https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjvFCnsro%253D&md5=fcbcb4db465ac7674b5559f7e8d4dafcGeometries and Stabilities of Re-Doped Sin (n = 1-12) Clusters: A Density Functional InvestigationHan, Ju-Guang; Ren, Zhao-Yu; Lu, Ben-ZuoJournal of Physical Chemistry A (2004), 108 (23), 5100-5110CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The possible ReSin (n = 1-12) clusters are investigated systematically at the UB3LYP level employing LanL2DZ basis sets for a sequence of different spin states. The total energies and equil. geometries, as well as natural populations and natural electron configurations, are calcd. The emphasis on the stabilities and fragmentation energies as well as on electronic properties is presented and discussed. Theor. results on natural populations reveal that the natural populations of 5d and 6s orbitals of the Re atom in ReSin (n = 1-12) clusters are assocd. with the no. of silicon atoms and spin of this species considered, that the natural population of the Re atom in the most stable ReSin (n = 1-12) clusters is recorded as neg., and that the charges in the most stable ReSin (n = 1-12) transfer from Si atoms and 6s orbitals of the Re atom to 5d orbitals of the Re atom. Therefore, the Re atom, which acts as an acceptor, plays an important role in the stability of ReSin (n = 1-12) clusters. Furthermore, the charge-transfer of ReSin (n = 1-12) depends on the spin of the species considered. Theor. results of equil. geometries on ReSin (n = 1-12) clusters show that the Re atom of the most stable ReSin (n = 1-7) occupies a surface site and absorbs on the surface site of the Si cluster; however, the Re atom of the most stable ReSin (n = 8-12) clusters is trapped in the center site of the Si cluster and directly interacts with all atoms simultaneously with nonequivalent bond lengths; this observation of transition metal (TM) behavior in TM-silicon clusters being favorable to the center site of the silicon frame when n > 7 is in good agreement with exptl. measurement on TbSix- (x = 6-16) clusters. Growth patterns of ReSin (n = 9-12) clusters are discussed showing the sandwichlike structure as the favorable structure. Relative stability is discussed upon removing one silicon atom, showing that ReSi2 and the sandwichlike ReSi12, ReSi11, and ReSi9 clusters have enhanced stability which is regarded as the abundance of the mass spectrometric observation on ReSin+ (n = 1-11). These theor. results are consistent with the at. averaged binding energies also. Comparisons of ReSin (n = 1-12) with available theor. results of MSin (n = 1-6, M = Cr, Mo, W, Ir) cluster series and exptl. measurements are made.
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385Reveles, J. U.; Khanna, S. N. Nearly-free-electron gas in a silicon cage. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 72, 165413, DOI: 10.1103/PhysRevB.72.165413Google ScholarThere is no corresponding record for this reference.
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386Wang, J.; Han, J.-G. Geometries, stabilities, and electronic properties of different-sized ZrSin (n = 1–16) clusters: A density-functional investigation. J. Chem. Phys. 2005, 123, 064306, DOI: 10.1063/1.1998887Google Scholar386https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpsVaitrw%253D&md5=a827004253f5ddb21200ee75d13b2ae0Geometries, stabilities, and electronic properties of different-sized ZrSin (n=1-16) clusters: A density-functional investigationWang, Jin; Han, Ju-GuangJournal of Chemical Physics (2005), 123 (6), 064306/1-064306/16CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The ZrSin (n = 1-16) clusters with different spin configurations have been systematically investigated by using the UB3LYP-DFT method. The total energies, equil. geometries, growth-pattern mechanisms, natural population anal., etc., are discussed. The equil. structures of different-sized ZrSin clusters can be detd. by two evolution patterns. The most stable ZrSin (n = 1-7) geometries, except ZrSi3, keep the analogous frameworks as the lowest-energy or the second lowest-energy Sin+1 clusters. However, for large ZrSin (n = 8-16) clusters, Zr atom obviously disturbs the framework of silicon clusters, and the localized position of the transition-metal (TM) Zr atom gradually varies from the surface insertion site to the concave site of the open silicon cage and to the encapsulated site of the sealed silicon cage. The lowest-energy sandwich-like ZrSi12 geometry is not a sealed structure and appears irregular as compared with other TM@Si12 (TM = Re,Ni). The growth patterns of ZrSin (n = 1-16) clusters show Zr-encapsulated structures as favorable geometries. The calcd. fragmentation energies of the ZrSin (n = 1-16) clusters manifest that the magic nos. of stabilities are 6, 8, 10, 14, and 16, and that the fullerenelike ZrSi16 is the most stable structure, which is in good agreement with the calcd. at. binding energies of ZrSin (n = 8-16) and with available exptl. and theor. results. The natural charge population of Zr atom in the most stable ZrSin (n = 1-16) structures varies from pos. to neg. at the crit.-sized ZrSi8 cluster; the charge distribution around the Zr atom appears clearly covalent in character for the small- or middle-sized clusters and metallic in character for the large-sized clusters. The properties of frontier orbitals and polarizabilities of ZrSin are also discussed.
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387Ma, L.; Zhao, J.; Wang, J.; Lu, Q.; Zhu, L.; Wang, G. Structure and electronic properties of cobalt atoms encapsulated in Sin (n = 1–13) clusters. Chem. Phys. Lett. 2005, 411, 279– 284, DOI: 10.1016/j.cplett.2005.06.062Google Scholar387https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXms1OrtL0%253D&md5=6f14ec1617d3d3ea762cbf83b1de4af1Structure and electronic properties of cobalt atoms encapsulated in Sin (n=1-13) clustersMa, Li; Zhao, Jijun; Wang, Jianguang; Lu, Qiliang; Zhu, Lianzhong; Wang, GuanghouChemical Physics Letters (2005), 411 (4-6), 279-284CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)A systematic theor. study of the equil. geometries and energetics of cobalt atoms encapsulated in Sin (n = 1-13) clusters in comparison with pure Sin clusters were done by DFT-GGA method combined with a genetic algorithm. The geometries of bare Sin clusters are substantially modified upon doping with Co atom; Co-doping improves the stability of the clusters for n ≥ 7. In general, the stability of SinCo clusters increases with increasing size n. The Si9Co was found to be magic-no. cluster; the enhanced stability was explained by the 18-electron rule. The magnetic moment on Co atom inside SinCo cluster is quenched in all clusters with n ≥ 4.
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388Guo, P.; Ren, Z.-Y.; Yang, A.-P.; Han, J.-G.; Bian, J.; Wang, G.-H. Relativistic computational investigation: The geometries and electronic properties of TaSin+ (n = 1–13, 16) clusters. J. Phys. Chem. A 2006, 110, 7453– 7460, DOI: 10.1021/jp060130fGoogle Scholar388https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XkslKhtbg%253D&md5=6814e3be3029aea42df63af5b0a5b1bdRelativistic Computational Investigation: The Geometries and Electronic Properties of TaSin+ (n = 1-13, 16) ClustersGuo, Ping; Ren, Zhao-Yu; Yang, A-Ping; Han, Ju-Guang; Bian, Jiang; Wang, Guang-HouJournal of Physical Chemistry A (2006), 110 (23), 7453-7460CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The equil. geometries, stabilities, and electronic properties of the TaSin+ (n = 1-13, 16) clusters are investigated systematically by using the relativistic d. functional method with generalized gradient approxn. The small-sized TaSin+ clusters with slight geometrical adjustments basically keep the frameworks that are analogous to the neutrals while the medium-sized charged clusters significantly deform the neutral geometries, which are confirmed by the calcd. AIP and VIP values. The optimized geometries of the charged clusters agree with the exptl. results of H. Hiura and co-workers (Phys. Rev. Lett. 2001, 86, 1733). The HOMO-LUMO gaps of the charged clusters are generally increased as the cluster size goes from n = 1 to 13; the large HOMO-LUMO gaps of charged clusters resulting from the pos. charge indicate that their chem. stabilities are stronger than their neutral counterparts, esp. for n = 4, 6, and 7 clusters. The contributions of the d orbitals of the Ta atom to the HOMO and LUMO reveal that the chem. activity of the d orbitals of the Ta atom decreases gradually as the no. of silicon atoms increases. This interesting finding is in good agreement with the recent exptl. results on the reactive activities of the H2O and transition-metal silicon clusters (Koyasu, K.; Akutsu, M.; Mitsui, M.; Nakajima, A. J. Am. Chem. Soc. 2005, 127, 4998). Generally, the pos. charge significantly influences the electronic and geometric structures of the charged clusters. The most stable neutral and charged TaSi16 clusters are found to be fullerene-like structures and the HOMO-LUMO gap in charged form is detectable exptl.
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389Ma, L.; Zhao, J.; Wang, J.; Wang, B.; Lu, Q.; Wang, G. Growth behavior and magnetic properties of SinFe (n = 2–14) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 73, 125439, DOI: 10.1103/PhysRevB.73.125439Google Scholar389https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjslGqtrc%253D&md5=2260f99f1f879fb8831ad7ba298c8f8eGrowth behavior and magnetic properties of SinFe (n=2-14) clustersMa, Li; Zhao, Jijun; Wang, Jianguang; Wang, Baolin; Lu, Qiliang; Wang, GuanghouPhysical Review B: Condensed Matter and Materials Physics (2006), 73 (12), 125439/1-125439/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The growth behavior and magnetic properties of SinFe (n = 2-14) clusters were studied using the d. functional theory (DFT) within the generalized gradient approxn. (GGA). Extensive search of the lowest-energy structures was conducted by considering a no. of structural isomers for each cluster size. In the ground state structures of SinFe clusters, the equil. site of Fe atom gradually moves from convex, to a surface, and to a concave site as the no. of Si atoms increases from 2 to 14. Starting from n = 10, the Fe atom completely falls into the center of the Si outer frame, forming metal-encapsulated Si cages. Maximum peaks were obsd. for SinFe clusters at n = 5, 7, 10, 12 on the size-dependence of 2nd-order energy difference, implying that these clusters possess relatively higher stability. The electronic structures and magnetic properties of SinFe clusters are discussed. The magnetic moment of the Fe atom in SinFe clusters is quenched around the size of n = 9-10, due to strong hybridization between the 4s and 3d states of Fe and the 3s and 3p states of Si.
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390Uchida, N.; Miyazaki, T.; Kanayama, T. Stabilization mechanism of Si12 cage clusters by encapsulation of a transition-metal atom: A density-functional theory study. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 205427, DOI: 10.1103/PhysRevB.74.205427Google Scholar390https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xhtleju73M&md5=c133a192ca2c1fe0ba83c3abdad03663Stabilization mechanism of Si12 cage clusters by encapsulation of a transition-metal atom: A density-functional theory studyUchida, Noriyuki; Miyazaki, Takehide; Kanayama, ToshihikoPhysical Review B: Condensed Matter and Materials Physics (2006), 74 (20), 205427/1-205427/9CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We systematically studied the geometrical and electronic structures of transition-metal (M) encapsulated in Si12 cage clusters, MSi12 (M = Hf, Ta, W, Re, Os, Ir, Pt, and Au), mainly focusing on their outstanding stability, using the B3PW91 and B3LYP DFT methods. The MSi12 clusters except HfSi12 belong to either of two distinct structural classes, the D6h-sym. hexagonal prism (HP; for M = Ta, W, Re, and Os; total no. of valence electrons per cluster, Nν, ranging from 53 to 56) and less-sym. four pentagonal face (FPF; M = Re, Os, Ir, Pt, and Au; Nν ranging from 55 to 59) structures. The HP structure is particularly stabilized at Nν = 54, which is understood in terms of the electronic shell closure of the M atoms due to the 18-electron rule, and the geometrical symmetry is maintained for Nν = 53, 55, and 56 by the covalent bonding between the M atom and the Si cage accompanied by the cage-to-M charge transfer. The FPF structure is lowest in energy for Nν = 56 and is maintained by the same covalent-bond/charge-transfer mechanism for other values of Nν. We propose that all these results originate from the electronic "rigidness" of the HP and FPF Si cages against the variation of Nν, which is the leading factor governing the stability of MSi12.
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391Reveles, J. U.; Khanna, S. N. Electronic counting rules for the stability of metal-silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 035435, DOI: 10.1103/PhysRevB.74.035435Google ScholarThere is no corresponding record for this reference.
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392Chen, Z.; Neukermans, S.; Wang, X.; Janssens, E.; Zhou, Z.; Silverans, R. E.; King, R. B.; Schleyer, P. v. R.; Lievens, P. To achieve stable spherical clusters: General principles and experimental confirmations. J. Am. Chem. Soc. 2006, 128, 12829– 12834, DOI: 10.1021/ja062868gGoogle Scholar392https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xptlelsbs%253D&md5=d09d1c28a715b5206633a593e9e21385To Achieve Stable Spherical Clusters: General Principles and Experimental ConfirmationsChen, Zhongfang; Neukermans, Sven; Wang, Xin; Janssens, Ewald; Zhou, Zhen; Silverans, Roger E.; King, R. Bruce; Schleyer, Paul von Rague; Lievens, PeterJournal of the American Chemical Society (2006), 128 (39), 12829-12834CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)General principles for designing stable highly sym. clusters are proposed. This approach takes advantage of both the extra stability of cage aromaticity and the good geometrical balance between the outer cage and the endohedral atom. The applicability of these design principles was confirmed by gas-phase exptl. observations on group 14 element cages with endohedral Al's and also is illustrated by many literature examples of diverse systems.
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393Koukaras, E. N.; Garoufalis, C. S.; Zdetsis, A. D. Structure and properties of the Ni@Si12 cluster from all-electron ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 73, 235417, DOI: 10.1103/PhysRevB.73.235417Google Scholar393https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmvFChtL4%253D&md5=432291d75450d05c8541ef41eff8ecd5Structure and properties of the Ni@Si12 cluster from all-electron ab initio calculationsKoukaras, Emmanuel N.; Garoufalis, Christos S.; Zdetsis, Aristides D.Physical Review B: Condensed Matter and Materials Physics (2006), 73 (23), 235417/1-235417/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The structural, electronic, and vibrational properties of the Ni@Si12 cluster have been studied using all-electron ab initio calcns. in the framework of the d. functional theory (DFT) with the hybrid nonlocal exchange and correlation functional of Becke-Lee-Yang-Parr (B3LYP). Perturbation theory was also used for the lowest energy competing structures in order to unambiguously identify the ground state in view of marginal total energy differences at the DFT/B3LYP level of theory. To facilitate possible future exptl. identification and to check the stability of the structures, we have performed vibrational analyses that include Raman and IR spectra for the stable structures. Through the vibrational anal., we have found that the C5v sym. Frank-Kasper structure, based on an icosahedral structural motif, which for some time was believed as the ground state, is unstable. Our calcns. reveal a ground state of "cubic" D2d symmetry, which at the fourth order of perturbation theory is about 1.3 eV lower than the alternative suggested ground state, based on a hexagonal structural motif. This distorted hexagonal structure of CS symmetry at the DFT/B3LYP level of theory is practically isoenergetic to our cubic D2d structure, with a marginal energy difference of about 0.04 eV. In addn. to IR and Raman spectra, we have examd. in detail electronic (bonding and binding), structural, and chem. characteristics that could be important for possible future applications of these or derived from these materials. Such characteristics include total and partial d. of states, crystal orbital overlap populations, binding energies, ionization potentials, electron affinities, "chem. hardness," and embedding energies.
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394Gueorguiev, G. K.; Pacheco, J.; Stafström, S.; Hultman, L. Silicon–metal clusters: Nano-templates for cluster assembled materials. Thin Solid Films 2006, 515, 1192– 1196, DOI: 10.1016/j.tsf.2006.07.114Google Scholar394https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtFKktLbK&md5=2020596c93d107b5cf568c1a35ffcf70Silicon-metal clusters: Nano-templates for cluster assembled materialsGueorguiev, G. K.; Pacheco, J. M.; Stafstroem, S.; Hultman, L.Thin Solid Films (2006), 515 (3), 1192-1196CODEN: THSFAP; ISSN:0040-6090. (Elsevier B.V.)The structure, cohesive energy and electronic properties of MSin clusters were studied by 1st-principles calcns. as a function of size (n) and (M). The authors studied 168 different clusters, contg. from 1 to 14 Si atoms together with one transition metal atom among 12 different elements: Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Pt, Cu, Ag, Au. Clusters with n = 7, 10, 12 appear as local maxima in cohesive energy, independently of the metal involved. This, together with previous findings for MSin (contg. 12 other transition metal elements), establishes a systematic behavior. For most metals, MSi12 and MSi10 (the smallest endohedral species) are highly sym. and exhibit local (with respect to their neighbors in size) stability. Thus, besides practically all MSi12 clusters (exceptions being HfSi12, ZrSi12), also some MSi10 such as VSi10, NiSi10, PdSi10, NbSi10 and AgSi10, are promising candidates as building blocks for cluster assembled materials. Electronic properties of structurally equiv. clusters depend markedly on the transition metal involved, providing the means to tailor pre-defined properties when designing extended phases.
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395Kumar, V. Novel metal-encapsulated caged clusters of silicon and germanium. Eur. Phys. J. D 2003, 24, 227– 232, DOI: 10.1140/epjd/e2003-00194-5Google Scholar395https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXntFehtro%253D&md5=edde3d7a8d4122f999b47cab625273b2Novel metal-encapsulated caged clusters of silicon and germaniumKumar, V.European Physical Journal D: Atomic, Molecular and Optical Physics (2003), 24 (1-3), 227-232CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)A review. We report the recent findings of metal (M) encapsulated clusters of silicon from computer expts. based on ab initio total energy calcns. and a cage shrinkage and atom removal approach. Our results show that using a guest atom, it is possible to wrap silicon in fullerenelike (f) structures, as sp2 bonding is not favorable to produce empty cages unlike for carbon. Transition M atoms have a strong bonding with the silicon cage that are responsible for the compact structures. The size and structure of the cage change from 14 to 20 Si atoms depending upon the size and valence of the M atom. Fewer Si atoms lead to relatively open structures. We find cubic, f, Frank-Kasper (FK) polyheral type, decahedral, icosahedral and hexagonal structures for M@Sin with n = 12-16 and several different M atoms. The magic behavior of 15 and 16 atom Si cages is in agreement with expts. The FK polyhedral cluster, M@Si16 has an exceptionally large d. functional gap of about 2.35 eV calcd. within the generalized gradient approxn. It is likely to give rise to visible luminescence in these clusters. The cluster-cluster interaction is weak that makes such clusters attractive for cluster assembled materials. Further studies to stabilize Si20 cage with M = Zr, Ba, Sr, and Pb show that in all cases there is a distortion of the f cage. Similar studies on M encapsulated germanium clusters show FK polyhedral and decahedral isomers to be more favorable. Also perfect icosahedral M@Ge12 and M@Sn12 clusters have been obtained with large gaps by doping with divalent M atoms. Recent results of the H interaction with these clusters, hydrogenated silicon fullerenes as well as assemblies of clusters such as nanowires and nanotubes are briefly presented.
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396Zorriasatein, S.; Joshi, K.; Kanhere, D. Dopant-induced stabilization of silicon clusters at finite temperature. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 045117, DOI: 10.1103/PhysRevB.75.045117Google Scholar396https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhs1ertLY%253D&md5=c3c7e6c98f489f811b2965f2cb558affDopant-induced stabilization of silicon clusters at finite temperatureZorriasatein, Shahab; Joshi, Kavita; Kanhere, D. G.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (4), 045117/1-045117/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)With the recent advances in miniaturization, understanding and controlling the properties of technol. significant materials such as Si in the nano regime assumes considerable importance. The Si clusters in the size range of 15-20 atoms are known to be unstable upon heating. For example, Si20 does not melt but fragments around 1250 K, whereas Si15 has a liq.-like phase spread over a short temp. range and undergoes fragmentation at approx. 1800 K. It is possible to suppress such a fragmentation process by introducing the appropriate dopant (in this case Ti). Specifically, by using the first-principles d. functional simulations we show that Ti-doped Si16, having the Frank-Kasper polyhedral, remains stable till at least 2200 K and fragments only above 2600 K. The obsd. melting transition is a 2-step process. The first step is initiated by the surface melting at approx. 600 K. In the second step, the destruction of the cage takes place at approx. 2250 K, giving rise to a peak in the heat capacity curve.
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397Zdetsis, A. D. Bonding and structural characteristics of Zn-, Cu-, and Ni-encapsulated Si clusters: Density-functional theory calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 085409, DOI: 10.1103/PhysRevB.75.085409Google Scholar397https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXislartb4%253D&md5=ac42491205e62fd78060d4915249ee0cBonding and structural characteristics of Zn-, Cu-, and Ni-encapsulated Si clusters: Density-functional theory calculationsZdetsis, Aristides D.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (8), 085409/1-085409/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The bonding and structural characteristics of metal (M) embedded silicon clusters M@Si12 and M@Si10, M=Zn,Cu,Ni have been studied in parallel within the framework of the d. functional theory with the hybrid nonlocal exchange and correlation functional of Becke and Lee, Yang and Parr (B3LYP). It is illustrated that for Zn and Cu, which are characterized by filled d shells the bonding and structure are largely characterized by the valence metal electrons, contrary to Ni and other transition metals where the bonding is dominated by the filling of the empty d shells by cage electrons. In M@S|i12 clusters there is a strong competition between cubic, icosahedral, and hexagonal prismatic structures. However, with the possible exception of Zn@Si12, the corresponding fully sym. Oh, Ih, and D6h structures for all three metals are statically and/or dynamically unstable due to Jahn-Teller distortions. In addn. to M@Si12, hydrogenated M@Si12H12, M=Ni,Zn clusters have been studied in order to examine the changes in the bonding and structural properties induced by satg. the dangling bonds with surface-hydrogen. In these clusters the effect of hydrogen consists in weakening considerable (up to zero) the metal-cage interactions, enhancing the sp3 cage interactions. This leads in many cases to empty hydrogenated silicon cages, after the removal of the metal atom, which are very stable and sym. with large highest occupied-LUMO (HOMO-LUMO) energy and optical gaps.
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398Wang, J.; Ma, Q.-M.; Xie, Z.; Liu, Y.; Li, Y.-C. From SinNi to Ni@Sin: An investigation of configurations and electronic structure. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 76, 035406, DOI: 10.1103/PhysRevB.76.035406Google Scholar398https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXos1ars7Y%253D&md5=97c6f1566b17b6e715e5be88b6bc95e6From SinNi to Ni@Sin: An investigation of configurations and electronic structureWang, Jing; Ma, Qing-Min; Xie, Zun; Liu, Ying; Li, You-ChengPhysical Review B: Condensed Matter and Materials Physics (2007), 76 (3), 035406/1-035406/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The configurations and electronic structure of SinNi (n = 1 - 14) clusters have been calcd. in the framework of all-electron d.-functional theory. The calcd. results reveal that the Ni atom prefers to occupy the surface site when n < 9 and for the clusters with n ≥ 9, the Ni atom starts to encapsulate in the cage. Furthermore, in the size dependence of embedding energy, max. peak is obsd. for SinNi clusters at n = 12, implying that the Si12Ni cluster is the most stable structure. The doped Ni atom enhances the stability of silicon clusters and helps to form the Ni-encapsulated Si cage. Consequently, all the calcd. results provide a further understanding of structural transformation and relative stabilities of metal-encapsulated Si cages.
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399Wang, J.; Zhao, J.; Ma, L.; Wang, B.; Wang, G. Structure and magnetic properties of cobalt doped Sin (n = 2–14) clusters. Phys. Lett. A 2007, 367, 335– 344, DOI: 10.1016/j.physleta.2007.01.093Google Scholar399https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXnvFyktL8%253D&md5=0738e9c36c1dd4d8ffdf4b4076928759Structure and magnetic properties of cobalt doped Si n (n = 2 - 14) clustersWang, Jianguang; Zhao, Jijun; Ma, Li; Wang, Baolin; Wang, GuanghouPhysics Letters A (2007), 367 (4-5), 335-344CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The structure and magnetic properties of Co-doped Sin (n = 2 - 14) clusters were systematically studied using d. functional theory (DFT). For each cluster size, extensive search of the lowest-energy structure was conducted by considering a no. of structural isomers. The equil. site of the Co atom in the ground-state structures of SinCo clusters gradually moves from convex, surface, to interior sites as the no. of Si atom increases from 2-14. Starting from Si10Co, Co atom is fully encapsulated by the Si outer cages. The magnetic moment of Co atom in SinCo clusters is completely quenched at n = 7 , due to charge transfer and strong hybridization between 4s and 3d states of Co and 3s and 3p states of Si.
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400Torres, M.; Balbás, L. Relative stability of Sin and SinSc- clusters in the range n = 14–18). Eur. Phys. J. D 2007, 43, 217– 220, DOI: 10.1140/epjd/e2007-00086-8Google Scholar400https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXls1KhtLc%253D&md5=f4ccacc33758d84fbcb3b06b2ede3427Relative stability of Sin and SinSc- clusters in the range n = 14-18Torres, M. B.; Balbas, L. C.European Physical Journal D: Atomic, Molecular, Optical and Plasma Physics (2007), 43 (1-3), 217-220CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)We present a first-principles DFT-GGA pseudopotential optimization of the lower energy equil. structure of SinSc- anions for n = 14-18. We find that Si16Sc- is more stable than its neighbors clusters, in agreement with recent exptl. mass spectra. We also optimize the geometry of pure Sin neutral clusters in the range n = 14-18, and compare our results with those from previous first-principles calcns.
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401Torres, M.; Fernández, E.; Balbás, L. Theoretical study of isoelectronic SinM clusters (M = Sc–, Ti, V+; n = 14–18. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 205425, DOI: 10.1103/PhysRevB.75.205425Google Scholar401https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntV2ntbY%253D&md5=4708604e2782535d0be343778d321788Theoretical study of isoelectronic SinM clusters (M = Sc-, Ti, V+; n = 14-18)Torres, M. B.; Fernandez, E. M.; Balbas, L. C.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (20), 205425/1-205425/12CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We study, from first-principles quantum mech. calcns., the structural and electronic properties of several low-lying energy equil. structures of isoelectronic SinM clusters (M = Sc-, Ti, V+) for n = 14-18. The main result is that those clusters with n = 16 are more stable than its neighbors, in agreement with recent exptl. mass spectra. By analyzing the orbital charge distribution and the partial orbital d. of states, that special stability is rationalized as a combination of geometrical (near spherical cagelike structure for n = 16) and electronic effects (l-selection rule of the spherical potential model). The structures of the two lowest energy isomers of Si16M are nearly degenerate, and consist of the Frank-Kasper polyhedron and a distortion of that polyhedron. The first structure is the ground state for M = V+, and the second is the ground state for Ti and Sc-. For the lowest energy isomers of clusters SinM with n = 14-18, we analyze the changes with size n, and impurity M of several quantities: binding energy, second difference of total energy, HOMO-LUMO gap, adiabatic electron affinity, addn. energy of a Si atom, and addn. energy of an M impurity to a pure Sin cluster. We obtain good agreement with available measured adiabatic electron affinities for SinTi.
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402Han, J.-G.; Zhao, R.-N.; Duan, Y. Geometries, stabilities, and growth patterns of the bimetal Mo2-doped Sin (n = 9–16) clusters: A density functional investigation. J. Phys. Chem. A 2007, 111, 2148– 2155, DOI: 10.1021/jp0661903Google Scholar402https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhvF2ru7Y%253D&md5=ffc0df94c129de887fc3933dfc549302Geometries, Stabilities, and Growth Patterns of the Bimetal Mo2-doped Sin (n = 9-16) Clusters: A Density Functional InvestigationHan, Ju-Guang; Zhao, Run-Ning; Duan, YuhuaJournal of Physical Chemistry A (2007), 111 (11), 2148-2155CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The authors studied bimetal Mo-Mo doped cage-like silicon clusters Mo2Sin using the DFT-B3LYP method. The growth-pattern, relative stabilities, and charge-transfer in these clusters are presented and discussed. The optimized geometries reveal that the dominant growth patterns of the bimetal Mo-Mo doped on opened cage-like silicon clusters (n = 9-13) are based on pentagon prism MoSi10 and hexagonal prism MoSi12; the Mo2 encapsulated Sin(n = 14-16) frames are dominant in the growth of larger clusters. The Mo2 dimer in the Sin frames is dissocd. due to interaction with the Sin frames. The calcd. fragmentation energies show that the stable clusters are Mo2-doped Si10 and Si12 clusters; the Mo2-doped Si10 is the most stable cluster. Natural population anal. shows that the charge-transfer in Mo2-doped Sin clusters is analogous to the charge transfer in Sin doped with Re or W single atoms. The frontier orbitals of Mo2-doped Sin (n = 10 and 12) clusters show that the Mo2Si10 and Mo2Si12 isomers have enhanced chem. stabilities due to larger HOMO-LUMO gaps. The geometry of the most stable Mo2Si9 cluster has the framework which is analogous to that of Ni2Ge9 cluster confirmed by recent exptl. observation (Goicoechea, J. M.; Sevov, S. C. J. Am Chem. Soc. 2006, 128, 4155).
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403Guo, L.-J.; Liu, X.; Zhao, G.-F.; Luo, Y.-H. Computational investigation of TiSin (n = 2–15) clusters by the density-functional theory. J. Chem. Phys. 2007, 126, 234704, DOI: 10.1063/1.2743412Google Scholar403https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntF2iuro%253D&md5=b601b683920b3b5eab62db0f139abfaaComputational investigation of TiSin (n = 2-15) clusters by the density-functional theoryGuo, Ling-Ju; Liu, Xia; Zhao, Gao-Feng; Luo, You-HuaJournal of Chemical Physics (2007), 126 (23), 234704/1-234704/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometries, stabilities, and electronic properties of TiSin (n = 2-15) clusters with different spin configurations were systematically investigated by using d.-functional theory approach at B3LYP/LanL2DZ level. The equil. site of Ti atom gradually moves from convex to surface, and to a concave site as the no. of Si atom increases from 2 to 15. The Ti atom in TiSi12 completely falls into the center of the Si outer frame, forming metal-encapsulated Si cages, which can be explained by using 16-electron rule. On the basis of the optimized geometries, various energetic properties were calcd. for the most stable isomers of TiSin clusters, including the av. binding energy, the HOMO and LUMO (HOMO-LUMO) gap, fragmentation energy, and the second-order difference of energy. For n = 6,8,12 the clusters are more stable than neighboring ones. According to the Mulliken charge population anal., charges always transfer from Si atoms to Ti atom. Furthermore, the HOMO-LUMO gaps of the most stable TiSin clusters are usually smaller than those of Sin clusters.
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404Chuang, F.-C.; Hsieh, Y.-Y.; Hsu, C.-C.; Albao, M. A. Geometries and stabilities of Ag-doped Sin (n = 1–13) clusters: A first-principles study. J. Chem. Phys. 2007, 127, 144313, DOI: 10.1063/1.2775447Google Scholar404https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtF2msbvM&md5=4f10917a6a6b5012a1279b3d0cd4590cGeometries and stabilities of Ag-doped Sin (n = 1-13) clusters: A first-principles studyChuang, Feng-Chuan; Hsieh, Yun-Yi; Hsu, Chih-Chiang; Albao, Marvin A.Journal of Chemical Physics (2007), 127 (14), 144313/1-144313/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures of AgSin (n = 1-13) clusters are investigated using first-principles calcns. Our studies suggest that AgSin clusters with n = 7 and 10 are relatively stable isomers and that these clusters prefer to be exohedral rather than endohedral. Moreover, doping leaves the inner core structure of the clusters largely intact. Addnl., the plot of fragmentation energies as a function of silicon atoms shows that the AgSin are favored to dissoc. into one Ag atom and Sin clusters. Alternative pathways exist for n > 7 (except n = 11) in which the Ag-Si cluster dissocs. into a stable Si7 and a smaller fragment AgSin-7. The AgSi11 cluster dissocs. into a stable Si10 and a small fragment AgSi. Lastly, our anal. indicates that doping of Ag atom significantly decreases the gaps between the HOMO and the LUMO for n > 7.
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405Guo, L.-j.; Zhao, G.-f.; Gu, Y.-z.; Liu, X.; Zeng, Z. Density-functional investigation of metal-silicon cage clusters MSin (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn; n = 8–16). Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 195417, DOI: 10.1103/PhysRevB.77.195417Google Scholar405https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmslOgsrs%253D&md5=dd975f43d31614b1b1b3ebb3c7d38277Density-functional investigation of metal-silicon cage clusters MSin (M=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn; n=8-16)Guo, Ling-ju; Zhao, Gao-feng; Gu, Yu-zong; Liu, Xia; Zeng, ZhiPhysical Review B: Condensed Matter and Materials Physics (2008), 77 (19), 195417/1-195417/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The geometries, stabilities, electronic, and magnetic properties of the transition metal encapsulated MSin (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn; n = 8-16) clusters have been systematically investigated by using d. functional theory with generalized gradient approxn. It is shown that every transition metal atom (TMA) will fall into the center of Si outer frame and form a metal-encapsulated Si cage at a certain size (ScSi14, TiSi12, VSi12, CrSi12, MnSi11, FeSi10, CoSi10, NiSi10 CuSi12, and ZnSi14). The size of the smallest cagelike structures cannot be detd. by the radius of the TMA alone; the bonding properties and the orbital hybridization between TMA and Si atoms also play an important role. The stability of the cagelike MSin clusters cannot be understood by electron shell filling (18 or 20 electrons) rule; it depends on other factors. The total magnetic moments of MSin clusters and the magnetic moments of TMA in MSin clusters are not always quenched when the TMA falls into the center of the Si outer frame.
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406Hossain, D.; Pittman, C. U., Jr; Gwaltney, S. R. Structures and stabilities of copper encapsulated within silicon nano-clusters: Cu@Sin (n = 9–15). Chem. Phys. Lett. 2008, 451, 93– 97, DOI: 10.1016/j.cplett.2007.11.067Google Scholar406https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXit1ansQ%253D%253D&md5=84c98e5c171665a04fb51da9caa91c52Structures and stabilities of copper encapsulated within silicon nano-clusters: Cu@Sin (n =9-15)Hossain, Delwar; Pittman, Charles U.; Gwaltney, Steven R.Chemical Physics Letters (2007), 451 (1-3), 93-97CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)D. functional electronic-structure calcns. were performed for Cu@Sin (n = 9-15) clusters. The lowest-energy endohedral structure and its stability for each Cu@in cluster were detd. The encapsulation of Cu within silicon clusters generates stable neutral Cu@in clusters. The binding energies and embedding energies of these clusters indicate that they are likely to be chem. stable. The relative cluster stabilities and other thermodn. properties alternate with cluster size, with an apparent preference existing for clusters with an even no. of Si atoms.
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407Yang, A.-P.; Ren, Z.-Y.; Guo, P.; Wang, G.-H. Geometries, stabilities, and electronic properties of Y-doped Sin (n = 1–16) clusters: A relativistic density functional investigation. J. Mol. Struct.: THEOCHEM 2008, 856, 88– 95, DOI: 10.1016/j.theochem.2008.01.016Google Scholar407https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXkvVGrt78%253D&md5=a8956206625747c06bed75ccb6884e23Geometries, stabilities, and electronic properties of Y-doped Sin (n =1-16) clusters: A relativistic density functional investigationYang, A.-Ping; Ren, Zhao-Yu; Guo, Ping; Wang, Guang-HouJournal of Molecular Structure: THEOCHEM (2008), 856 (1-3), 88-95CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)The geometries, stabilities, and electronic properties of YSin (n = 1-16) clusters are investigated systematically via a relativistic d. functional theory with the generalized gradient approxn. For n = 1-14, the most stable YSin geometries generally are analogous to the low-lying Sin+1 clusters; in the size range n = 11-14, they are prolate in shape and form sandwich structures with Y atom occupying a surface site. When the cluster size goes up to 15, the Y atom abruptly drops into the silicon cage, together with the alteration in the direction of charge transfer revealed by the Hirshfeld charge anal. The calcd. at. averaged binding energies and fragmentation energies manifest that the YSin (n = 2, 5, 8, 11, and 14) clusters have remarkably enhanced stabilities. Moreover, the HOMO-LUMO gaps of YSin clusters are universally narrow, compared with those of pure silicon clusters. The calcd. HOMO and LUMO energies for Y-encapsulated YSin (n = 15, 16) are evidently lower than those of the small-sized YSin (n = 1-14) clusters.
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408Peng, Q.; Shen, J. Growth behavior of La@Sin (n = 1–21) metal-encapsulated clusters. J. Chem. Phys. 2008, 128, 084711, DOI: 10.1063/1.2834691Google Scholar408https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtVGqu78%253D&md5=6119a4aa2b48bd9cbe5bd9af05b12b3dGrowth behavior of La@Sin (n = 1-21) metal-encapsulated clustersPeng, Qi; Shen, JiangJournal of Chemical Physics (2008), 128 (8), 084711/1-084711/11CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)D. functional theory involving generalized gradient approxn. correlation functional is used to investigate the cluster series La@Sin (n = 1-21). We find that the growth process of La@Sin (n = 1-21) could be divided into three stages: First, La atom adheres to other Si atoms in the size range of 1 ≤ n ≤ 10; then, La atom is surrounded by Si atoms with basketlike structures in the size range of 11 ≤ n ≤ 15; finally, La atom is completely encapsulated into the fullerene cage structures in the size range of 16 ≤ n ≤ 21. The growth of fullerene cage starts from La@Si16 and stops at La@Si20. By studying La@Sin+ cations and La@Sin- anions, we find that the La atom charge curves of neutral clusters, cations, and anions have a cross point at La@Si12. Adiabatic ionization potential and electron affinity are studied too. Lastly, based on the ground state geometries of La@Sin clusters, we simulate the chem. reaction in which La@SinH2n+ cation has been produced and explain why Hiura et al. only obsd. La@SinH2n+ (n = 1-4) cations in their expt. (c) 2008 American Institute of Physics.
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409Wang, J.; Liu, J. H. Investigation of size-selective Zr2@Sin (n = 16–24) caged clusters. J. Phys. Chem. A 2008, 112, 4562– 4567, DOI: 10.1021/jp801828bGoogle Scholar409https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXltVyjsb8%253D&md5=c2223110b8b027e21e394d5f1bd6bca2Investigation of Size-Selective Zr2@Sin (n = 16-24) Caged ClustersWang, Jin; Liu, Jin HuaiJournal of Physical Chemistry A (2008), 112 (20), 4562-4567CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The size-selective Zr2Sin (n = 16-24) caged clusters were investigated by DFT methods. Their geometries, relative stabilities, electronic properties and ionization potentials are been discussed. The dominant structures of bimetallic Zr2 doped silicon caged clusters gradually transform to Zr2 totally encapsulated structures with increase of the cluster size from 16 to 24, which is good agreement with the recent exptl. result (J. Phys. Chem. A. 2007, 111, 42). Two novel isomers, i.e., naphthalene-like and dodecahedral Zr2Si20 clusters, were found. Novel quasi-1D naphthalene-like ZrnSim nanotubes are reported. The second-order energy differences reveal that magic nos. of the different sized neutral Zr2Sin clusters appear at n = 18, 20 and 22, which are attributed to the fullerene-like, dodecahedral and polyhedral structures, resp. The HOMO-LUMO gaps ( > 1 eV) of all the size-selective Zr2Sin clusters suggest that encapsulation of the bimetallic zirconium atoms is favorable for increasing the stabilities of silicon cages.
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410Bandyopadhyay, D. A density functional theory–based study of the electronic structures and properties of cage like metal doped silicon clusters. J. Appl. Phys. 2008, 104, 084308, DOI: 10.1063/1.3000657Google Scholar410https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlWks7vL&md5=db035739c73279180debd5d8759cb340A density functional theory-based study of the electronic structures and properties of cage like metal doped silicon clustersBandyopadhyay, DebashisJournal of Applied Physics (2008), 104 (8), 084308/1-084308/7CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Ab initio electronic-structure calcns. were performed by using d. functional theory with polarized basis set (LanL2DZ) within the spin polarized generalized gradient approxn. for metal (M = Ti,Zr,Hf) doped Sin clusters where n varies from 9 to 20. In the first step of the calcn., geometrical optimizations of the nanoclusters have been done. In the next step, these optimized geometries have been used to calc. the binding energy (BE) and HOMO-LUMO gap (ΔEg) of the clusters. In order to check the stability of the clusters, the second order energy differences of the optimized geometries have been calcd. To study the optical behavior of the clusters, IR and Raman spectra calcn. have been done. Further calcns. on cation and anion clusters have been done to obtain their ionization potential (IP), electron affinity (EA), and chem. potential. (c) 2008 American Institute of Physics.
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411Bandyopadhyay, D.; Kumar, M. The electronic structures and properties of transition metal-doped silicon nanoclusters: A density functional investigation. Chem. Phys. 2008, 353, 170– 176, DOI: 10.1016/j.chemphys.2008.08.017Google Scholar411https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht12jurbN&md5=f7f592b0698ec6a1ccd40c426a07954fThe electronic structures and properties of transition metal-doped silicon nanoclusters: A density functional investigationBandyopadhyay, Debashis; Kumar, ManishChemical Physics (2008), 353 (1-3), 170-176CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)We report an ab initio all electron mol.-orbital electronic-structure calcn. by using d. functional theory (DFT) and with polarized basis set (LanL2DZ) within the spin polarized generalized gradient approxn. for metal-doped silicon clusters, SinM (n = 14-20 and M = Ti, Zr, Hf). As the first step of calcn., geometrical optimizations of the nanoclusters were done. These optimized geometries were used to calc. the binding energy and HOMO-LUMO gap (band gap) of the clusters. In order to check the dynamical stability of the clusters, IR and Raman spectra were calcd. Further calcns. were done on cation and anion clusters to obtain ionization potential (IP), electron affinity (EA), chem. potential and chem. hardness of the optimized clusters.
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412Bandyopadhyay, D. The study of the electronic structures and properties of pure and transition metal-doped silicon nanoclusters: A density functional theory approach. Mol. Simul. 2009, 35, 381– 394, DOI: 10.1080/08927020802603598Google Scholar412https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjsFensL0%253D&md5=54e41f1e02dbeeb1d35fffb961362361The study of the electronic structures and properties of pure and transition metal-doped silicon nanoclusters: a density functional theory approachBandyopadhyay, DebashisMolecular Simulation (2009), 35 (5), 381-394CODEN: MOSIEA; ISSN:0892-7022. (Taylor & Francis Ltd.)This report presents the study of ab initio electronic structure and properties of pure and transition metal (TM = Ti, Zr and Hf)-doped silicon clusters, TM@i(n), by using d. functional theory with a polarized basis set (LanL2DZ) within the spin-polarised generalized gradient approxn. for different values of n varying from 8 to 20. As the first step of the study, different optimized geometries of pure and doped clusters are calcd. These optimized clusters are then used to calc. different structural and phys. parameters of the clusters, like binding energy, HOMO - LUMO (HOMO-LUMO) gap, charge transfer, etc. In order to check the stability of the clusters, the second-order difference in the energy of the optimized structures is calcd. To study the optical behavior of the clusters, IR and Raman spectra are also calcd. Further calcns. are also done on cation and anion clusters of both pure and doped nanoclusters to obtain their ionization potential, electron affinity and chem. potential. An effort has been made to correlate the variation of different calcd. parameters with the size of the clusters to explain the real existence and stabilities of different TM-doped clusters.
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413Zhao, G.-f.; Sun, J.-m.; Gu, Y.-z.; Wang, Y.-x. Density-functional study of structural, electronic, and magnetic properties of the EuSin (n = 1–13) clusters. J. Chem. Phys. 2009, 131, 114312, DOI: 10.1063/1.3232009Google Scholar413https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFGrsb%252FL&md5=0b33b799fe4a76e0d579b4c874c5af56Density-functional study of structural, electronic, and magnetic properties of the EuSin (n = 1-13) clustersZhao, Gao-feng; Sun, Jian-min; Gu, Yu-zong; Wang, Yuan-xuJournal of Chemical Physics (2009), 131 (11), 114312/1-114312/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometries, stabilities, and electronic and magnetic properties of europium encapsulated EuSin (n = 1-13) clusters were studied systematically by using relativistic d. functional theory with generalized gradient approxn. Starting from n = 12, the Eu atom completely falls into the center of the Si frame, i.e., EuSi12 is the smallest fully endohedral Eu silicon cluster. The interesting finding is in good agreement with the recent exptl. results on the photoelectron spectroscopy of the europium silicon clusters. The magnetic moments of the EuSin (n = 1-13) clusters are also studied, and the total magnetic moments of the EuSin clusters and the magnetic moments on Eu do not quench when the Eu is encapsulated in the Si outer frame cage. Most of the 4f electrons of the Eu atom in the EuSi12 cluster do not interact with the silicon cage and the total magnetic moments are overwhelming majority contributed by the 4f electrons of the Eu atom. According to the binding energy per atom, the 2nd difference in energy (Δ2E), and vertical ionization potential, the EuSin (n = 4, 9, 12) clusters are very stable. (c) 2009 American Institute of Physics.
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414Lan, Y.-Z.; Feng, Y.-L. Comparative study on the geometric and energetic properties, absorption spectra, and polarizabilities of charged and neutral Cu@Sin clusters (n = 9–14). Phys. Rev. A: At., Mol., Opt. Phys. 2009, 79, 033201, DOI: 10.1103/PhysRevA.79.033201Google Scholar414https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXktVymsr0%253D&md5=7c72e240f68503d3efa5da5f51a2fe37Comparative study on the geometric and energetic properties, absorption spectra, and polarizabilities of charged and neutral Cu @ Sin clusters (n=9-14)Lan, You-Zhao; Feng, Yun-LongPhysical Review A: Atomic, Molecular, and Optical Physics (2009), 79 (3, Pt. B), 033201/1-033201/9CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)The comparative study on the geometric and energetic properties, absorption spectra, and polarizabilities of cagelike CuSin clusters (n = 9-14; indicated by Cu @ Sin) was performed using the d.-functional theory. The influence of a charge on these properties was studied. The charge has more effect on the geometry of Cu @ Sin (n = 9, 11, and 13) than Cu @ Sin (n = 10, 12, and 14). For n = 10-13, the charge directly leads the neutral geometry to the transition state geometry with 1 imaginary frequency. The influence of a charge on the overall and relative stabilities of the neutral and charged Cu @ Sin clusters was analyzed based on the binding energy, energy gap, adiabatic electron affinity, adiabatic ionization potential, and 2nd-order energy difference. The charge slightly increases the binding energy by ∼0.13 eV. For the charged clusters, those with n = 10, 12, and 14 still have a higher relative stability than those with n = 9, 11, and 13. In the visible range, the shape of the absorption spectra is not influenced by a charge. However, the charge results in a blueshift of the absorption spectra. The order of anion°neutral°cation for the static isotropic polarizabilities does not apply to the dynamic isotropic polarizabilities at some optical-field frequencies due to the 1-photon resonance, which is based on the absorption spectra and the sum-over-states formula of the polarizabilities. The charge significantly affects the static anisotropic polarizabilities because the charge influences the geometry of the clusters. The charge also influences the resonant behavior of the dynamic polarizabilities due to its effect on the absorption spectra.
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415Wang, J.; Liu, J. H. Novel bi-transition metallic encapsulated naphthalene-like Si20 prismatic cage: A DFT investigation. J. Comput. Chem. 2009, 30, 1103– 1110, DOI: 10.1002/jcc.21137Google Scholar415https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXltFSlsrc%253D&md5=f3718b2e7676852af248c180c25b72f2Novel bi-transition metallic encapsulated naphthalene-like Si20 prismatic cage: a DFT investigationWang, Jin; Liu, Jin HuaiJournal of Computational Chemistry (2009), 30 (7), 1103-1110CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)A theor. investigation of stabilities and electronic properties of novel transition bimetallic atoms (BTMAs) encapsulated naphthalene-like Si20 prismatic cage is being reported for the first time. The symmetry and electronic state of naphthalene-like TMA2@Si20 is significantly affected by the type of encapsulated TMA from 3d, 4d to 5d series. Because of high binding energies, relative high HOMO-LUMO gaps, large charge-reverse transferring from naphthalene-like Si20 cage to BTMAs at the center of the 5d series, the most stable species of TMA2@Si20 cage is favorable to form new 1D-TMAn@Sim nanotube, which is based on array of the novel naphthalene-like structure.
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416Li, J.-r.; Yao, C.-h.; Mu, Y.-w.; Wan, J.-g.; Han, M. Structures and magnetic properties of SinNi (n = 1–17) clusters. J. Mol. Struct.: THEOCHEM 2009, 916, 139– 146, DOI: 10.1016/j.theochem.2009.09.027Google Scholar416https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlOks7rE&md5=06d759cced8cc6fc4a91f7c1c0e3e92cStructures and magnetic properties of SinNi (n =1-17) clustersLi, Jian-rong; Yao, Chang-hong; Mu, Yue-wen; Wan, Jian-guo; Han, MinJournal of Molecular Structure: THEOCHEM (2009), 916 (1-3), 139-146CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)The structure, electronic and magnetic properties of SinNi clusters up to n = 17 are systematically investigated using the d.-functional theory (DFT) within the generalized gradient approxn. (GGA). In the ground configurations of SinNi clusters, the equil. site of Ni atom gradually moves from convex, to a surface, and to a concave site as the no. of Si atoms varying from 1 to 17. Starting from n = 8, the Ni atom completely falls into the center of the Si outer frame, forming Ni-encapsulated Si cages. Maximum peaks of second-order energy difference are found at n = 5, 7, 10, 12 and 14, indicating that these clusters possess relatively higher stability. Esp., Si10Ni cluster is more stable. The electronic structures and magnetic properties of SinNi clusters are discussed. The strong hybridization between Ni 4s, 3d, 4p and Si 3s, 3p states leads to the decrease of the gaps between highest-occupied and lowest-unoccupied MOs of SinNi clusters compared with corresponding those of Sin clusters and may be one of important factors which result in SinNi clusters magnetic moment quenched except for Si2Ni cluster.
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417He, J.; Wu, K.; Liu, C.; Sa, R. Stabilities of 3d transition-metal doped Si14 clusters. Chem. Phys. Lett. 2009, 483, 30– 34, DOI: 10.1016/j.cplett.2009.10.052Google Scholar417https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVaisb3F&md5=ff68a0d009f52de40664ad5c65f1ac1aStabilities of 3d transition-metal doped Si14 clustersHe, Jiangang; Wu, Kechen; Liu, Caiping; Sa, RongjianChemical Physics Letters (2009), 483 (1-3), 30-34CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometries, electronic structures, and stabilities of MSi14 clusters (M = Sc-Ni) were studied by using the DFT-B3LYP method. The cage composed of 14 Si atoms can completely encapsulate a 3d transition-metal atom. The binding forces of MSi14 clusters mainly originate from the electrostatic and orbital interactions. In binding (or embedding) energy calcn., the Wigner-Witmer spin conservation rule is needed in the cases of CrSi14 and MnSi14. Only CrSi14 shows simultaneously the highest stability and chem. inertness indicating that only 20-electron rule can be applied to MSi14 species.
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418Wang, J.; Ma, Q.-M.; Xu, R.-P.; Liu, Y.; Li, Y.-C. 3d transition metals: Which is the ideal guest for Sin (n = 15, 16) cages?. Phys. Lett. A 2009, 373, 2869– 2875, DOI: 10.1016/j.physleta.2009.05.072Google Scholar418https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXosVWqtL8%253D&md5=ddee616e2cef0ff9fddde792e1a6b94e3d transition metals: Which is the ideal guest for Sin ( n = 15 , 16 ) cages?Wang, Jing; Ma, Qing-Min; Xu, Rui-Ping; Liu, Ying; Li, You-ChengPhysics Letters A (2009), 373 (32), 2869-2875CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The configurations, stability, and electronic structures of Si15 and Si16 cages with encapsulated 3d transition metal atoms, M@Si15 and M@Si16 (M = Sc, Ti, V, Cr, Mn, Fe, Co, or Ni), have been investigated within the framework of all-electron d. functional theory. The results show that Ti@Si16 and Ti@Si15 have the largest embedding energies in this series and relatively large HOMO-LUMO gaps. This suggests that the titanium atom is an ideal guest for Sin ( n = 15 , 16 ) cages as far as stability is concerned. The Mn atom is found to have a large spin moment even when encapsulated, while the spin moments of Ti, Cr, Fe, and Ni are entirely quenched upon doping into the Si15 and Si16 cage clusters.
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419Zdetsis, A.; Koukaras, E.; Garoufalis, C. A parallel study of Ni@Si12 and Cu@Si12 nanoclusters. J. Math. Chem. 2009, 46, 971– 980, DOI: 10.1007/s10910-009-9549-xGoogle Scholar419https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVGgsrjP&md5=9f0037ac4bf0417746171210968da44fA parallel study of Ni@Si12 and Cu@Si12 nanoclustersZdetsis, A. D.; Koukaras, E. N.; Garoufalis, C. S.Journal of Mathematical Chemistry (2009), 46 (3), 971-980CODEN: JMCHEG; ISSN:0259-9791. (Springer)The Ni@Si12 and Cu@Si12 clusters are studied in parallel within the framework of the d. functional theory using the hybrid functional of Becke-Lee, Parr and Yang (B3LYP), emphasizing the differences and similarities in structural and electronic properties. The dominant structures for both clusters are a distorted hexagonal structure of Cs symmetry and a distorted octahedral structure of D2d. For Ni@Si12 the two structures are practically isoenergetic whereas for Cu@Si12 the energy difference of the D2d structure from the lowest Cs structure of hexagonal origin is about 0.7 eV, at the B3LYP/TZVP level of theory. Contrary to Cu@Si12 for which the well known Frank-Kasper (FK) structure of C5v symmetry is a real local min. of the energy hyper-surface (although higher by more than 1.6 eV from the global min.), for Ni@Si12 the FK structure is dynamically unstable. The HOMO-LUMO gaps, the binding energies per atom and the embedding energies for Cu@Si12 clusters are smaller by 0.5, 0.1 and 1.1 eV, resp. compared to the Ni@Si12 clusters. This is attributed to different type of bonding in the two clusters.
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420Li, J.-r.; Wang, G.-h.; Yao, C.-h.; Mu, Y.-w.; Wan, J.-g.; Han, M. Structures and magnetic properties of SinMn (n = 1–15) clusters. J. Chem. Phys. 2009, 130, 164514, DOI: 10.1063/1.3123805Google Scholar420https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlsVGnu70%253D&md5=c90d9fcc6449287eb83a4c7f53901f06Structures and magnetic properties of SinMn (n=1-15) clustersLi, Jian-rong; Wang, Guang-hou; Yao, Chang-hong; Mu, Yue-wen; Wan, Jian-guo; Han, MinJournal of Chemical Physics (2009), 130 (16), 164514/1-164514/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structure, electronic, magnetic properties of SinMn clusters up to n=15 are systematically investigated using the d. functional theory within the generalized gradient approxn. In the most stable configurations of SinMn clusters, the equil. site of Mn atom gradually moves from convex, to a surface, and to a concave site as the no. of Si atoms varying from 1 to 15. Starting from n=11, the Mn atom completely falls into the center of the Si outer frame, forming Mn-encapsulated Si cages. Maximum peaks of second-order energy difference are found at n=6, 8, 10, and 12, indicating that these clusters possess relatively higher stability. The electronic structures and magnetic properties of SinMn clusters are discussed. The magnetic moment of SinMn clusters mainly is located on Mn atom. The 3d electrons in Mn atom play a dominant role in the detn. of the magnetism of Mn atom in SinMn clusters. Furthermore, the moment of Mn atom in SinMn clusters exhibits oscillatory behavior and are quenched at n>7 except for n=12, mainly due to the charge transfer, strong hybridization between Mn 4s, 3d, 4p and Si 3s, 3p states. (c) 2009 American Institute of Physics.
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421Reis, C.; Pacheco, J. Vibrational spectra of silicon cage clusters doped with Ti, Zr, or Hf. Phys. Rev. B: Condens. Matter Mater. Phys. 2010, 82, 155440, DOI: 10.1103/PhysRevB.82.155440Google Scholar421https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlKlt7%252FP&md5=84f67f239b9c0e9eebf362a6f98108c8Vibrational spectra of silicon cage clusters doped with Ti, Zr, or HfReis, C. L.; Pacheco, J. M.Physical Review B: Condensed Matter and Materials Physics (2010), 82 (15), 155440/1-155440/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors study the vibrational modes and IR spectra of the exceptionally stable isovalent X @ Si16 (X = Ti, Zr, and Hf) nanoparticles, making use of 1st-principles d.-functional theory. The results predict the existence of high-intensity modes of low frequency. An est. of the electron-phonon coupling strength λ is also provided based on a single-mol. method introduced recently. The large value of λ combined with predicted stability of bulk materials assembled with these nanoparticles suggest that these materials, when appropriately doped, may exhibit high-temp. superconducting properties.
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422Wang, J.; Liu, Y.; Li, Y.-C. Magnetic silicon fullerene. Phys. Chem. Chem. Phys. 2010, 12, 11428– 11431, DOI: 10.1039/b923865dGoogle Scholar422https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFartb%252FM&md5=d99f5b69a1bd93aae2a510f4dae9b2aeMagnetic silicon fullereneWang, Jing; Liu, Ying; Li, You-ChengPhysical Chemistry Chemical Physics (2010), 12 (37), 11428-11431CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)A metal-encapsulating silicon fullerene, Eu@Si20, was predicted by d. functional theory to be by far the most stable fullerene-like silicon structure. The Eu@Si20 structure is a dodecahedron with D2h symmetry in which the europium atom occupies the center site. The calcd. results show that the europium atom has a large magnetic moment of nearly 7.0 μB. A stable pearl necklace nanowire, constructed by concatenating Eu@Si20 units, with the central europium atom, retains the high spin moment. The magnetic structure of the nanowire indicates potential applications in the fields of spintronics and high-d. magnetic storage.
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423Wang, J.; Liu, Y.; Li, Y.-C. Au@Sin: Growth behavior, stability and electronic structure. Phys. Lett. A 2010, 374, 2736– 2742, DOI: 10.1016/j.physleta.2010.04.068Google Scholar423https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmtlCqtbc%253D&md5=b243d518ac167f15f942bf36670bd537Au@Sin: Growth behavior, stability and electronic structureWang, Jing; Liu, Ying; Li, You-ChengPhysics Letters A (2010), 374 (27), 2736-2742CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The configurations, stability, and electronic structure of Au@Sin (n=1-16) clusters have been investigated within the framework of the d. functional theory at the B3PW91/LanL2DZ and PW91/DNP levels. The results show that the Au atom begins to occupy the interior site for cages as small as Si11 and for Si12 the Au atom completely falls into the interior site forming Au@Si12 cage. A relatively large embedding energy and small HOMO-LUMO gap are also found for this Au@Si12 structure indicating enhanced chem. activity and good electronic transfer properties. All these make Au@Si12 attractive for cluster-assembled materials.
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424Willand, A.; Gramzow, M.; Ghasemi, S. A.; Genovese, L.; Deutsch, T.; Reuter, K.; Goedecker, S. Structural metastability of endohedral silicon fullerenes. Phys. Rev. B: Condens. Matter Mater. Phys. 2010, 81, 201405, DOI: 10.1103/PhysRevB.81.201405Google Scholar424https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvVOisL8%253D&md5=fc8a908cbe44f3a011c937cd1eff60c3Structural metastability of endohedral silicon fullerenesWilland, Alex; Gramzow, Matthias; Alireza Ghasemi, S.; Genovese, Luigi; Deutsch, Thierry; Reuter, Karsten; Goedecker, StefanPhysical Review B: Condensed Matter and Materials Physics (2010), 81 (20), 201405/1-201405/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Endohedrally doped Si20 fullerenes appear as appealing building blocks for nanoscale materials. We investigate their structural stability with an unbiased and systematic global geometry optimization method within d.-functional theory. For a wide range of metal-doping atoms, it was sufficient to explore the Born-Oppenheimer surface for only a moderate no. of local min. to find structures that clearly differ from the initial endohedral cages but are considerably more favorable in terms of energy. Previously proposed structures are thus all metastable.
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425Palagin, D.; Gramzow, M.; Reuter, K. On the stability of “non-magic” endohedrally doped Si clusters: A first-principles sampling study of MSi16+ (M = Ti, V, Cr). J. Chem. Phys. 2011, 134, 244705, DOI: 10.1063/1.3604565Google Scholar425https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXotV2ht78%253D&md5=468727ec4011161c306c8a83cb190d2aOn the stability of "non-magic" endohedrally doped Si clusters: A first-principles sampling study of MSi16+ (M = Ti,V,Cr)Palagin, Dennis; Gramzow, Matthias; Reuter, KarstenJournal of Chemical Physics (2011), 134 (24), 244705/1-244705/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)D.-functional theory is used to study the geometric and electronic structure of cationic Si16+ clusters with a Ti, V, or Cr dopant atom. Through unbiased global geometry optimization based on the basin-hopping approach, we confirm that a Frank-Kasper polyhedron, with the metal atom at the center, represents the ground-state isomer for all three systems. The endohedral cage geometry is thus stabilized even though only VSi16+ achieves electronic shell closure within the prevalent spherical potential model. Our anal. of the electronic structure traces this diminished role of shell closure for the stabilization back to the adaptive capability of the metal-Si bonding, which is more the result of a complex hybridization than the originally proposed mere formal charge transfer. The resulting flexibility of the metal-Si bond can also help to stabilize "non-magic" cage-dopant combinations, which suggests that a wider range of materials may eventually be cast into this useful geometry for cluster-assembled materials. (c) 2011 American Institute of Physics.
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426Cantera-López, H.; Balbás, L.; Borstel, G. First-principles calculations of structural and electronic properties of Ta-doped Si clusters, wires, and bulk systems. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 83, 075434, DOI: 10.1103/PhysRevB.83.075434Google Scholar426https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXis1Cntbs%253D&md5=8c3c5e7bbe422a493ccb291634f76bb9First-principles calculations of structural and electronic properties of Ta-doped Si clusters, wires, and bulk systemsCantera-Lopez, H.; Balbas, L. C.; Borstel, G.Physical Review B: Condensed Matter and Materials Physics (2011), 83 (7), 075434/1-075434/9CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Recent expts. have shown that Ta@Si16+ is a very stable cation from which it should be possible to create Si-based cluster assembled materials. In this paper we have studied, by means of first-principles spin-dependent generalized gradient approxn. calcns., the structural and electronic properties of the following systems: (i) Ta@Sin+ clusters in the range n=14-18; (ii) (Ta@Si16F)m aggregates with sizes m=1-8 formed by Ta@Si16F mols.; (iii) infinite wires formed by stacking triangular (Ta@Si16F)3 aggregates twisted 60° to each other along the vertical axis; and (iv) the fcc phase of bulk Ta@Si16F. The min.-energy Ta@Si16+ cluster shows C3v symmetry, having 40 meV smaller total energy than a fullerenelike D4d isomer. However, the mol. Ta@Si16F formed with that D4d isomer is 40 meV more stable than that formed with the C3v one. We have optimized several [Ta@Si16F]n aggregates (n=1-8) which contain the Ta@Si16 unit with D4d symmetry. The more bound (Ta@Si16F)6 aggregate is formed by stacking vertically two triangular (Ta@Si16F)3 aggregates which are twisted 60° to each other. The infinite wire formed with that (Ta@Si16F)6 aggregate as the unit cell has a cohesive energy 1.88 eV and a small HOMO-lowest occupied MO gap. We have optimized also a metastable fcc bulk phase having the Ta@Si16F supermol. as the unit cell. A Birch-Murnaghan fit to that phase produces a cohesive energy 0.84 eV at lattice const. 12.27 A, with bulk modulus 7.55 GPa and a phase stability to isotropic compression smaller than 0.75 GPa. That phase is nonmagnetic and shows a band gap of 0.20 eV. Using the values of hardness of Ta@Si16F mols., we estd. a correction enhancement factor ∼3 to that small band gap. For that metastable solid we performed a 13.5-ps run of first-principles mol. dynamics annealing at 300 K and const. vol., and we found that the Ta@Si16F supermol. in the fcc cell becomes severely distorted after the first 5 ps.
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427Oña, O. B.; Ferraro, M. B.; Facelli, J. C. Transition from exo to endo Cu absorption in CuSin clusters: A genetic algorithms density functional theory study. Mol. Simul. 2011, 37, 678– 688, DOI: 10.1080/08927020903583830Google Scholar427https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXovFGgsro%253D&md5=9001fc69da19d68cd4b595a666a7b33cTransition from exo to endo Cu absorption in CuSin clusters: a genetic algorithms density functional theory studyOna, Ofelia B.; Ferraro, Marta B.; Facelli, Julio C.Molecular Simulation (2011), 37 (8), 678-688CODEN: MOSIEA; ISSN:0892-7022. (Taylor & Francis Ltd.)The characterization and prediction of the structures of metal silicon clusters is important for nanotechnol. research because these clusters can be used as building blocks for nanodevices, integrated circuits and solar cells. Several authors have postulated that there is a transition between exo and endo absorption of Cu in Sin clusters and showed that, for n larger than 9, it is possible to find endohedral clusters. Unfortunately, no global searches have confirmed this observation, which is based on local optimizations of plausible structures. Here, we use parallel genetic algorithms (GAs), as implemented in our modified genetic algorithms (MGAC) software, directly coupled with d. functional theory energy calcns. to show that the global search of CuSin cluster structures does not find endohedral clusters for n < 8 but finds them for n ≥ 10.
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428Liu, T.-g.; Zhao, G.-f.; Wang, Y.-x. Structural, electronic and magnetic properties of GdSin (n = 1–17) clusters: A density functional study. Phys. Lett. A 2011, 375, 1120– 1127, DOI: 10.1016/j.physleta.2011.01.023Google Scholar428https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1Cju7c%253D&md5=8f04062dcba3f9b1ddeda5be0c834c96Structural, electronic and magnetic properties of GdSin (n=1-17) clusters: A density functional studyLiu, Tai-gang; Zhao, Gao-feng; Wang, Yuan-xuPhysics Letters A (2011), 375 (7), 1120-1127CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The geometries, stabilities, electronic and magnetic properties of GdSin (n=1-17) clusters have been investigated systematically by using d. functional theory (DFT) with the generalized gradient approxn. (GGA). We find that the Gd atom in the lowest-energy configuration gradually moves from convex to surface, and to the interior site as the no. of Si atom varies from 1 to 17. Furthermore, from GdSi16, Gd atom in GdSi16 cluster completely falls into the center of the Si framework and forms a fullerene cage. On the basis of the at. av. binding energy [Eb(n)], the second difference in energy (Δ2E) and VIP, we predict that the magic no. of GdSin (n=1-17) clusters should be 5, 11 and 16, and these clusters should be abundant in the mass spectra when n=5, 11 and 16. The magnetic moments of the GdSin clusters are also studied. It is found that the total magnetic moments and the magnetic moments on Gd of GdSin clusters are large, and they do not quench when Gd is encapsulated in Si outer framework cage, which is to a large extent due to the fact that the Gd 4f electrons hardly interact with the silicon cage.
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429Ziella, D. H.; Caputo, M. C.; Provasi, P. F. Study of geometries and electronic properties of AgSin clusters using DFT/TB. Int. J. Quantum Chem. 2011, 111, 1680– 1693, DOI: 10.1002/qua.22815Google Scholar429https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvVKju74%253D&md5=4884311930675114359412228e7b18efStudy of geometries and electronic properties of AgSin clusters using DFT/TBZiella, D. H.; Caputo, M. C.; Provasi, P. F.International Journal of Quantum Chemistry (2011), 111 (7/8), 1680-1693CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)We present a theor. study of the structures of silver silicon clusters, AgSin, n = 1-15, using d. functional tight binding methods. We discuss in detail the search for silicon clusters stabilized by silver dopage, their dissocn. paths, and electronic properties. We also investigate the properties of silver encapsulated structures and compare them with those obtained when replacing the silver atom by different metals. Our results are checked against exptl. measurements when available. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010.
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430Dognon, J.-P.; Clavaguéra, C.; Pyykkö, P. A new, centered 32-electron system: The predicted [U@Si20]6–-like isoelectronic series. Chem. Sci. 2012, 3, 2843– 2848, DOI: 10.1039/c2sc20448gGoogle Scholar430https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFWns7zI&md5=69933fdb50e4df9cc594ce9cfb8431b6A new, centered 32-electron system: the predicted [U@Si20]6--like isoelectronic seriesDognon, Jean-Pierre; Clavaguera, Carine; Pyykkoe, PekkaChemical Science (2012), 3 (9), 2843-2848CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)In addn. to Lewis' octets and Langmuir's 18-electron principle, 32-electron centered systems are possible. We now propose a new, third example on 32e-bonding between a central metal atom and a ligand cage. Moreover, these actinide-filled Si20 clusters could lead to novel silicon nanostructures.
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431Xu, H.-G.; Wu, M. M.; Zhang, Z.-G.; Yuan, J.; Sun, Q.; Zheng, W. Photoelectron spectroscopy and density functional calculations of CuSin– (n = 4–18) clusters. J. Chem. Phys. 2012, 136, 104308, DOI: 10.1063/1.3692685Google Scholar431https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjvVers7w%253D&md5=013852c946bd74ee90ebc1ecb24081c5Photoelectron spectroscopy and density functional calculations of CuSin- (n = 4-18) clustersXu, Hong-Guang; Wu, Miao Miao; Zhang, Zeng-Guang; Yuan, Jinyun; Sun, Qiang; Zheng, WeijunJournal of Chemical Physics (2012), 136 (10), 104308/1-104308/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We conducted a combined anion photoelectron spectroscopy and DFT-B3LYP study on the structural evolution of copper-doped silicon clusters, CuSin- (n = 4-18). Based on the comparison between the expts. and theor. calcns., CuSi12- is suggested to be the smallest fully endohedral cluster. The low-lying isomers of CuSin- with n ≥ 12 are dominated by endohedral structures, those of CuSin- with n < 12 are dominated by exohedral structures. The most stable structure of CuSi12- is a double-chair endohedral structure with the copper atom sandwiched between two chair-style Si6 rings or, in another word, encapsulated in a distorted Si12 hexagonal prism cage. CuSi14- has an interesting C3h symmetry structure, in which the Si14 cage is composed by three four-membered rings and six five-membered rings. (c) 2012 American Institute of Physics.
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432Kong, X.; Xu, H.-G.; Zheng, W. Structures and magnetic properties of CrSin– (n = 3–12) clusters: Photoelectron spectroscopy and density functional calculations. J. Chem. Phys. 2012, 137, 064307, DOI: 10.1063/1.4742065Google Scholar432https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFKms7zE&md5=c68b8938c05b0cb92a42bce80f300a70Structures and magnetic properties of CrSin- (n = 3-12) clusters. Photoelectron spectroscopy and density functional calculationsKong, Xiangyu; Xu, Hong-Guang; Zheng, WeijunJournal of Chemical Physics (2012), 137 (6), 064307/1-064307/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Cr-doped Si clusters, CrSin- (n = 3-12), were investigated with anion photoelectron spectroscopy and d. functional theory calcns. The combination of exptl. measurement and theor. calcns. reveals that the onset of endohedral structure in CrSin- clusters occurs at n = 10 and the magnetic properties of the CrSin- clusters are correlated to their geometric structures. The most stable isomers of CrSin- from n = 3-9 have exohedral structures with magnetic moments of 3-5 μB while those of CrSi10-, CrSi11-, and CrSi12- have endohedral structures and magnetic moments of 1μB. (c) 2012 American Institute of Physics.
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433Kong, X.-Y.; Deng, X.-J.; Xu, H.-G.; Yang, Z.; Xu, X.-L.; Zheng, W.-J. Photoelectron spectroscopy and density functional calculations of AgSin– (n = 3–12) clusters. J. Chem. Phys. 2013, 138, 244312, DOI: 10.1063/1.4811659Google Scholar433https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVaitL%252FI&md5=d5197cdd035b437f085f23ebc867a398Photoelectron spectroscopy and density functional calculations of AgSin- (n = 3-12) clustersKong, Xiang-Yu; Deng, Xiao-Jiao; Xu, Hong-Guang; Yang, Zheng; Xu, Xi-Ling; Zheng, Wei-JunJournal of Chemical Physics (2013), 138 (24), 244312/1-244312/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We investigated the structural evolution and electronic properties of AgSin- (n = 3-12) clusters using anion photoelectron spectroscopy and d. functional theory calcns. The vertical detachment energies and adiabatic detachment energies of AgSin- (n = 3-12) clusters were estd. from their photoelectron spectra. The structures of the AgSin- (n = 3-12) clusters were tentatively assigned based on the comparison of theor. calcns. and exptl. measurements. The studies show that the structures of AgSin- (n = 3-12) clusters are dominated by exohedral structures with the Ag atom occupying the low coordinated sites. No endohedral structure has been found for AgSin- clusters with n ≤ 12. (c) 2013 American Institute of Physics.
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434Ma, L.; Wang, J.; Wang, G. Site-specific analysis of dipole polarizabilities of heterogeneous systems: Iron-doped Sin (n = 1–14) clusters. J. Chem. Phys. 2013, 138, 094304, DOI: 10.1063/1.4793276Google Scholar434https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtlOisbg%253D&md5=404e908e6bfbfb27c0175c94bd494801Site-specific analysis of dipole polarizabilities of heterogeneous systems: Iron-doped Sin (n = 1-14) clustersMa, Li; Wang, Jianguang; Wang, GuanghouJournal of Chemical Physics (2013), 138 (9), 094304/1-094304/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Following the recent work of decompg. the total dipole moment and polarizability of a homogeneous system into site-specific contributions, we extend the study to the heterogeneous systems of iron-doped Sin (n = 1-14) clusters by introducing a weighting function. The structure-/shape- and size-specific aspects of the dipole moments and polarizabilities of SinFe (n = 1-14) clusters are analyzed and compared with pure silicon clusters. It is shown that the polarizabilities assocd. with the individual constituent atoms vary considerably with the structure/shape of the cluster and the location of the atom or site within a given structure. For atoms at peripheral sites, the polarizabilities are substantially larger than atoms at the interior sites, and the more peripheral an atom is, the larger is its polarizability. The polarizability of the Fe atom in SinFe clusters decreases as the cluster size increases. This is related to the position of Fe atom in SinFe clusters and indicates significant screening of the interior of the cluster by its surface. The correlation between the anisotropy of the total polarizability and the anisotropy of the cluster shape is also analyzed. Comparing with pure Sin clusters, the polarizabilities of Si atoms are increased after Fe atom doping. The structures are more compact for SinFe than the same sizes of Sin+1 clusters and the polarizabilities of SinFe are smaller than Sin+1 for the sizes of n = 7-14. (c) 2013 American Institute of Physics.
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435Oliveira, M.; Rivelino, R.; de Brito Mota, F.; Gueorguiev, G. K. Optical properties and quasiparticle band gaps of transition-metal atoms encapsulated by silicon cages. J. Phys. Chem. C 2014, 118, 5501– 5509, DOI: 10.1021/jp409967aGoogle Scholar435https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXis1ensr4%253D&md5=6bc9ad4eb6c37c76e5defc88aa197429Optical Properties and Quasiparticle Band Gaps of Transition-Metal Atoms Encapsulated by Silicon CagesOliveira, M. I. A.; Rivelino, R.; de Brito Mota, F.; Gueorguiev, G. K.Journal of Physical Chemistry C (2014), 118 (10), 5501-5509CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Semiconductors assembled upon nanotemplates consisting of metal-encapsulating Si cage clusters (M@Si) have been proposed as prospective materials for nanodevices. To make an accurate and systematic prediction of the optical properties of such M@Si clusters, which represent a new type of metal-silicon hybrid material for components in nanoelectronics, we have performed first-principles calcns. of the electronic properties and quasiparticle band gaps for a variety of M@Si12 (M = Ti, Cr, Zr, Mo, Ru, Pd, Hf, and Os) and M@Si16 (M = Ti, Zr, and Hf) clusters. At first stage, the electronic structure calcns. have been performed within plane-wave d. functional theory in order to predict equil. geometries, polarizabilities, and optical absorption spectra of these endohedral cagelike clusters. The quasiparticle calcns. were performed within the GW approxn., which predict that all of these systems are semiconductors exhibiting large band gaps. The present results have demonstrated that the independent-particle absorption spectra of M@Si, calcd. within the local d. or generalized gradient approxns. to d. functional theory, are dramatically influenced by many-body effects. On av., the quasiparticle band gaps were significantly increased, in comparison with the independent-particle gaps, giving values in the 2.45-5.64 eV range. Consequently, the inclusion of many-body effects in the electron-electron interaction, and going beyond the mean-field approxn. of independent particles, might be essential to realistically describe the optical spectra of isolated M@Si clusters, as well as their cluster-assembled materials.
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436Oliveira, M. J.; Medeiros, P. V.; Sousa, J. R.; Nogueira, F.; Gueorguiev, G. K. Optical and magnetic excitations of metal-encapsulating Si cages: A systematic study by time-dependent density functional theory. J. Phys. Chem. C 2014, 118, 11377– 11384, DOI: 10.1021/jp4096562Google Scholar436https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXns1Cnsb0%253D&md5=7cee1d64d3e750103d5898317b2cbea5Optical and Magnetic Excitations of Metal-Encapsulating Si Cages: A Systematic Study by Time-Dependent Density Functional TheoryOliveira, Micael J. T.; Medeiros, Paulo V. C.; Sousa, Jose R. F.; Nogueira, Fernando; Gueorguiev, Gueorgui K.Journal of Physical Chemistry C (2014), 118 (21), 11377-11384CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A systematic study of the optical and magnetic excitations of 12 MSi12 and four MSi10 transition metal encapsulating Si cages has been carried out by employing real time time-dependent d. functional theory. Criteria for the choice of transition metals (M) are clusters' stability, synthesizability, and diversity. It was found that both the optical absorption and the spin-susceptibility spectra are mainly detd. by, in decreasing order of importance, (1) the cage shape, (2) the group in the Periodic Table to which M belongs, and (3) the period of M in the Periodic Table. Cages with similar structures and metal species that are close to each other in the Periodic Table possess spectra sharing many similarities; for example, the optical absorption spectra of the MSi12 (M = V, Nb, Ta, Cr, Mo, and W), which are highly sym. and belong to groups 4 and 5 of the Periodic Table, all share a very distinctive peak at around 4 eV. In all cases, although some of the obsd. transitions are located at the Si skeleton of the cages, the transition metal species is always significant for the optical absorption and the spin-susceptibility spectra. Our results provide fingerprint data for identification of gas-phase MSi12 and MSi10 by optical absorption spectroscopy.
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437Liu, T.-G.; Zhang, W.-Q.; Li, Y.-L. First-principles study on the structure, electronic and magnetic properties of HoSin (n = 1–12, 20) clusters. Front. Phys. 2014, 9, 210– 218, DOI: 10.1007/s11467-013-0398-5Google ScholarThere is no corresponding record for this reference.
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438Zhao, R.-N.; Han, J.-G.; Duan, Y. Density functional theory investigations on the geometrical and electronic properties and growth patterns of Sin (n = 10–20) clusters with bimetal Pd2 impurities. Thin Solid Films 2014, 556, 571– 579, DOI: 10.1016/j.tsf.2014.02.019Google Scholar438https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtlGgtLc%253D&md5=9e545173800b955252ee5ed85a0227eaDensity Functional theory investigations on the geometrical and electronic properties and growth patterns of Sin (n = 10-20) clusters with bimetal Pd2 impuritiesZhao, Run-Ning; Han, Ju-Guang; Duan, YuhuaThin Solid Films (2014), 556 (), 571-579CODEN: THSFAP; ISSN:0040-6090. (Elsevier B.V.)The geometrical and electronic properties and growth patterns of the bimetal Pd2 doped Sin (n = 10-20) clusters have been studied systematically by d. functional theory. The growth-pattern behaviors, relative stabilities, and chem. bonding of these clusters are presented and discussed. The optimized geometries exhibit that the dominant growth patterns of Pd2Sin (n = 10-20) are based on the pentagonal prism PdSi10. The bimetal Pd2 is doped on the opened cage-like silicon clusters (Sin) with the range of size n = 10-15, while doped on bigger silicon clusters (Sin, n = 16-20), the Pd2 are completely encapsulated inside Sin frames. The geometrical configurations of the encapsulated Pd2 in the Sin frames are varied due to the interactions between Pd2 and Sin frames. The calcd. fragmentation energies reveal that the remarkable stable Pd2Sin clusters with n = 11, 13, 16, 18, and 20 are obsd. Among all different-size clusters, the Pd2-doped Si16 is the most stable cluster. Particularly, the cage-like Pd2Si16 geometry is obviously distinct as compared to the single transition metal doped silicon cluster. Interestingly, the crit. size of geometry transition is explored at n = 16. Natural population anal. manifests that the charge-transfer phenomena in the Pd2-doped Sin clusters are similar to those of the single TM doped silicon clusters. In addn., the Pd2Sin (n = 10, 13, 14, 16, and 17) isomers have enhanced chem. stabilities because of their larger gaps between the highest occupied orbital and the lowest unoccupied orbital.
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439Borshch, N.; Kurganskii, S. Geometric structure, electron-energy spectrum, and growth of anionic scandium-silicon clusters ScSin- (n = 6–20). J. Appl. Phys. 2014, 116, 124302, DOI: 10.1063/1.4896528Google Scholar439https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsF2lsL%252FO&md5=c5ed331024b80da940b5f46f60ff5a53Geometric structure, electron-energy spectrum, and growth of anionic scandium-silicon clusters ScSin- (n = 6-20)Borshch, N.; Kurganskii, S.Journal of Applied Physics (Melville, NY, United States) (2014), 116 (12), 124302/1-124302/8CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Results of the geometric structure optimization and calcd. electron spectra of anion ScSi-n clusters (n = 6-20) are presented. Calcns. were carried out within the d. functional theory DFT-B3LYP framework. Real geometric structures of ScSin- clusters were established by the comparison of calcd. and known exptl. data. Formation of stable endohedral clusters is possible for n ≥ 14, for clusters with smaller no. of silicon atoms exohedral or longitudinal structures are preferable. (c) 2014 American Institute of Physics.
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440Abreu, M. B.; Reber, A. C.; Khanna, S. N. Does the 18-electron rule apply to CrSi12?. J. Phys. Chem. Lett. 2014, 5, 3492– 3496, DOI: 10.1021/jz501868tGoogle Scholar440https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhs1Cit7bM&md5=97cc238911272a0e7f146524f1976e13Does the 18-Electron Rule Apply to CrSi12?Abreu, Marissa Baddick; Reber, Arthur C.; Khanna, Shiv N.Journal of Physical Chemistry Letters (2014), 5 (20), 3492-3496CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Understanding the bonding between silicon and transition metals is valuable for devising strategies for incorporating magnetic species into silicon. CrSi12 is the std. example of a cluster whose apparent high stability has been explained by the 18-electron rule. We critically examine the bonding and nature of stability of CrSi12 and show that its electronic structure does not conform to the 18-electron rule. Through theor. studies, we find that CrSi12 has 16 effective valence electrons assigned to the Cr atom and an unoccupied 3dz2 orbital. We demonstrate that the cluster's apparent stability is rooted in a crystal field-like splitting of the 3d orbitals analogous to that of square planar complexes. CrSi14 is shown to follow the 18-electron rule and exhibits all conventional markers characteristic of a magic cluster.
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441Zhao, R.-N.; Han, J.-G. Geometrical stabilities and electronic properties of Sin (n = 12–20) clusters with rare earth holmium impurity: A density functional investigation. RSC Adv. 2014, 4, 64410– 64418, DOI: 10.1039/C4RA11828FGoogle Scholar441https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVGhsbrF&md5=b6a0a1c32ed45af3396a7d013bb241b1Geometrical stabilities and electronic properties of Sin (n = 12-20) clusters with rare earth holmium impurity: a density functional investigationZhao, Run-Ning; Han, Ju-GuangRSC Advances (2014), 4 (110), 64410-64418CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)HoSin (n = 12-20) clusters with different spin states have been systematically investigated by using d. functional theory with the generalized gradient approxn. The total energies, growth-pattern and equil. geometries as well as the APT charges of the HoSin (n = 12-20) clusters are calcd. The relative stabilities in terms of the calcd. at. averaged binding energies and fragmentation energies are discussed, revealing that the cake-like HoSin (n = 16, 18, 20) clusters have enhanced stabilities. Furthermore, the HOMO - LUMO (HOMO-LUMO) gaps of the HoSin (n = 12-17) are above 1.55 eV while HoSi16 has the largest one (1.95 eV). Interestingly, the calcd. dipole moments of the cake-like HoSin (n = 16, 18, 20) clusters are very small, corresponding to the global min. According to the calcd. APT charges of the Ho atom in the HoSin (n = 12-20) clusters, the contribution of charge-transfer to the stability of HoSin clusters is briefly discussed, manifesting that the charges in HoSin clusters transfer from the Si atoms to the Ho atom. Addnl., the optimized geometries show that the rare earth Ho atom is completely encapsulated into the center of the Si frame at n = 15. This finding is in good agreement with the available exptl. results.
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442Xu, H.-G.; Kong, X.-Y.; Deng, X.-J.; Zhang, Z.-G.; Zheng, W.-J. Smallest fullerene-like silicon cage stabilized by a V2 unit. J. Chem. Phys. 2014, 140, 024308, DOI: 10.1063/1.4861053Google Scholar442https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmtlSluw%253D%253D&md5=957ddd12a06a3426cb17b8356480b5b7Smallest fullerene-like silicon cage stabilized by a V2 unitXu, Hong-Guang; Kong, Xiang-Yu; Deng, Xiao-Jiao; Zhang, Zeng-Guang; Zheng, Wei-JunJournal of Chemical Physics (2014), 140 (2), 024308/1-024308/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The authors conducted a combined anion photoelectron spectroscopy and d. functional theory study on V2Si20 cluster. The V2Si20 cluster has an elongated dodecahedron cage structure with a V2 unit encapsulated inside the cage. It is the smallest fullerene-like silicon cage and can be used as a building block to make cluster-assembled materials, such as pearl-chain style nanowires. (c) 2014 American Institute of Physics.
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443Huang, X.; Xu, H.-G.; Lu, S.; Su, Y.; King, R.; Zhao, J.; Zheng, W. Discovery of a silicon-based ferrimagnetic wheel structure in VxSi12– (x = 1–3) clusters: Photoelectron spectroscopy and density functional theory investigation. Nanoscale 2014, 6, 14617– 14621, DOI: 10.1039/C4NR03130JGoogle Scholar443https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFeisb3N&md5=9a5a1cc90ad64b700b8b60dfca34f4a5Discovery of a silicon-based ferrimagnetic wheel structure in VxSi12- (x = 1-3) clusters: photoelectron spectroscopy and density functional theory investigationHuang, Xiaoming; Xu, Hong-Guang; Lu, Shengjie; Su, Yan; King, R. B.; Zhao, Jijun; Zheng, WeijunNanoscale (2014), 6 (24), 14617-14621CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Our studies show that VSi12- adopts a V-centered hexagonal prism with a singlet spin state. The addn. of the second V atom leads to a capped hexagonal antiprism for V2Si12- in a doublet spin state. Most interestingly, V3Si12- exhibits a ferrimagnetic, bicapped hexagonal antiprism wheel-like structure with a total spin of 4μB.
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444Huang, X.; Lu, S.-J.; Liang, X.; Su, Y.; Sai, L.; Zhang, Z.-G.; Zhao, J.; Xu, H.-G.; Zheng, W. Structures and electronic properties of V3Sin– (n = 3–14) clusters: A combined ab Initio and experimental study. J. Phys. Chem. C 2015, 119, 10987– 10994, DOI: 10.1021/jp5112845Google Scholar444https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFOgsbjJ&md5=322d1228decdbd72b683b2e73a696d48Structures and Electronic Properties of V3Sin- (n = 3-14) Clusters: A Combined Ab Initio and Experimental StudyHuang, Xiaoming; Lu, Sheng-Jie; Liang, Xiaoqing; Su, Yan; Sai, Linwei; Zhang, Zeng-Guang; Zhao, Jijun; Xu, Hong-Guang; Zheng, WeijunJournal of Physical Chemistry C (2015), 119 (20), 10987-10994CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Vanadium-doped silicon cluster anions, V3Sin- (n = 3-14), have been generated by laser vaporization and investigated by anion photoelectron spectroscopy. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) of these clusters were obtained. Meanwhile, genetic algorithm (GA) combined with d. functional theory (DFT) calcns. are employed to det. their ground-state structures systematically. Excellent agreement is found between theory and expt. Among the V3Sin- clusters, V3Si5-, V3Si9-, and V3Si12- are relatively more stable. Generally speaking, three V atoms prefer to stay close with others and form strong V-V bonds. Starting from V3Si11-, cage configurations with one interior V atom emerge.
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445Lin, L.; Yang, J. Small copper-doped silicon clusters CuSin (n = 4–10) and their anions: Structures, thermochemistry, and electron affinities. J. Mol. Model. 2015, 21, 155, DOI: 10.1007/s00894-015-2702-5Google Scholar445https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2MfntlWhuw%253D%253D&md5=bd65012a857b93cd3f70a54385c362f3Small copper-doped silicon clusters CuSin (n = 4-10) and their anions: structures, thermochemistry, and electron affinitiesLin Lin; Yang JucaiJournal of molecular modeling (2015), 21 (6), 155 ISSN:.The structures and energies of copper-doped small silicon clusters CuSi n (n = 4-10) and their anions were investigated systematically using CCSD(T)/aug-cc-pVTZ-DK//MP2/6-31G(2df,p), G4//MP2/6-31G(2df,p), and the B3LYP/6-311+G* basis set. The performance of the methods used for the prediction of energetic and thermodynamic properties was evaluated. Comparing experimental [Xu et al. (2012) J Chem Phys 136:104308] and theoretical calculations, it was concluded that the CCSD(T) results are very accurate and exhibit the best performance; the mean absolute deviation from experimental data was 0.043 eV. The excellent agreement of vertical detachment energy (VDE) between experimental results and CCSD(T) calculations indicates that the ground state structures of CuSi n (-) (n = 4-10) presented in this paper are reliable. For CuSi10, assigning 2.90±0.08 eV to the experimental adiabatic electron affinity (AEA) and 3.90±0.08 eV to the VDE is more reasonable than to 3.46±0.08 eV and 3.62±0.08 eV, respectively, based on the CCSD(T) calculations and the previous photoelectron spectrum of CuSi10 (-) (Xu et al., op. cit.). The AEAs of CuSi n (n = 4-10), excluding CuSi7, are in excellent agreement with experimental data, showing that the ground state structures of CuSi n (n = 4-6, 8-10) reported in this paper are reliable. CuSi10 is suggested to be the smallest endohedral ground state structure. However, adding an additional electron to CuSi10 pulls out the Cu atom from the center location, forming an exohedral ground state structure of CuSi10 (-). The charge transfer and dissociation energy of Cu from CuSi n and their anions determined to examine the nature of bonding and their relative stabilities.
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446Abreu, M. B.; Reber, A. C.; Khanna, S. N. Making sense of the conflicting magic numbers in WSin clusters. J. Chem. Phys. 2015, 143, 074310, DOI: 10.1063/1.4928755Google Scholar446https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlOgsb7K&md5=99f99de65fd50391b94260c3a684d59cMaking sense of the conflicting magic numbers in WSin clustersAbreu, Marissa Baddick; Reber, Arthur C.; Khanna, Shiv N.Journal of Chemical Physics (2015), 143 (7), 074310/1-074310/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)First principles studies on the geometric structure, stability, and electronic structure of WSin clusters, n = 6-16, have been carried out to show that the obsd. differing "magic sizes" for WSin clusters are assocd. with the nature of the growth processes. The WSi12 cluster, obsd. as a magic species in expts. reacting transition metal ions with silane, is not stable due to a filled shell of 18 electrons, as previously proposed, but due to its at. structure that arrests further growth because of an endohedral transition metal site. In fact, it is found that all of these clusters, n = 6-16, have filled 5d shells except for WSi12, which has a 5d8 configuration that is caused by crystal field splitting. The stability of WSi15+, obsd. as highly stable in clusters generated by vaporizing silicon and metal carbonyls, is shown to be assocd. with a combination of geometric and electronic features. The findings are compared with previous results on CrSin clusters. (c) 2015 American Institute of Physics.
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447Chauhan, V.; Abreu, M. B.; Reber, A. C.; Khanna, S. N. Geometry controls the stability of FeSi14. Phys. Chem. Chem. Phys. 2015, 17, 15718– 15724, DOI: 10.1039/C5CP01386KGoogle Scholar447https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXosFKksbw%253D&md5=c45fb58bfe4d0a4db679ee6bfbc820ddGeometry controls the stability of FeSi14Chauhan, Vikas; Abreu, Marissa Baddick; Reber, Arthur C.; Khanna, Shiv N.Physical Chemistry Chemical Physics (2015), 17 (24), 15718-15724CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)First-principles DFT-PBE theor. studies have been carried out to investigate the stability of Sin cages impregnated with a Fe atom. It is shown that FeSi9, FeSi11, and FeSi14 clusters exhibit enhanced local stability as seen through an increase in Si binding energy, Fe embedding energy, the gap between the HOMO and the LUMO, and the Ionization Potential (IP). The conventional picture for the stability of such species combines an assumption of electron precise bonding with the 18-electron rule; however, we find this to be inadequate to explain the enhanced stability in FeSi11 and FeSi14 because the d-band is filled for all FeSin clusters for n ≥ 9. FeSi14 is shown to be the most stable due to a compact and highly sym. Si14 cage with octahedral symmetry that allows better mixing between Fe 3d- and Si 3p-electronic states.
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448Goicoechea, J. M.; McGrady, J. E. On the structural landscape in endohedral silicon and germanium clusters, M@Si12 and M@Ge12. Dalton Trans. 2015, 44, 6755– 6766, DOI: 10.1039/C4DT03573AGoogle Scholar448https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVWms70%253D&md5=ae6d46d385fd6bfe6641af51c2559a79On the structural landscape in endohedral silicon and germanium clusters, M@Si12 and M@Ge12Goicoechea, Jose M.; McGrady, John E.Dalton Transactions (2015), 44 (15), 6755-6766CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)Amongst the endohedral clusters of the tetrel elements, M@En, the 12-vertex species are unique in that three completely different geometries, the icosahedron (Ih, [Ni@Pb12]2-), the hexagonal prism (HP, Cr@Si12) and the bicapped pentagonal prism (BPP, [Ru@Ge12]3-) have been identified in stable mols. We explore here the origins of this structural diversity by comparing stability patterns across isovalent and isoelectronic series, M@Si12, M@Ge12 and [M@Ge12]3-. The BPP structure dominates the structural landscape for high valence electron counts (57-60) while the HP has a rather narrower window of stability around the 54-56 count. Moreover the preference for an HP structure is unique to silicon: in no case is a rigorously D6h-sym. structure the global min. for M@Ge12. Distortions from the high-symmetry limits, where present, can be traced to degeneracies or near-degeneracies in the frontier orbital domains. In all cases the structure adopted is that which maximizes the delocalization of electron d. between the metal and the cluster cage, such that both components attain stable electronic configurations.
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449Arcisauskaite, V.; Fijan, D.; Spivak, M.; de Graaf, C.; McGrady, J. E. Biradical character in the ground state of [Mn@Si12]+: A DFT and CASPT2 study. Phys. Chem. Chem. Phys. 2016, 18, 24006– 24014, DOI: 10.1039/C6CP03534EGoogle Scholar449https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht12ks7vN&md5=9837f6574d60270998e2b6b4753feff1Biradical character in the ground state of [Mn@Si12]+: a DFT and CASPT2 studyArcisauskaite, Vaida; Fijan, Domagoj; Spivak, Mariano; Graaf, Coen de; McGrady, John E.Physical Chemistry Chemical Physics (2016), 18 (34), 24006-24014CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Both d. functional theory and multi-configurational ab initio (CASPT2) calcns. are used to explore the potential energy surface of the hexagonal prismatic cluster [Mn@Si12]+. Unlike isoelectronic Cr@Si12, the ground state is a biradical, with triplet and open-shell singlet states lying very close in energy. The results are discussed in the context of recent exptl. studies using infra-red multiple photon dissocn. spectroscopy and X-ray MCD spectroscopy.
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450Xia, X. X.; Hermann, A.; Kuang, X. Y.; Jin, Y. Y.; Lu, C.; Xing, X. D. Study of the structural and electronic properties of neutral and charged niobium-doped silicon clusters: Niobium encapsulated in silicon cages. J. Phys. Chem. C 2016, 120, 677– 684, DOI: 10.1021/acs.jpcc.5b09453Google Scholar450https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVGrsLvK&md5=14a5645da017969b053621dc48b5c585Study of the Structural and Electronic Properties of Neutral and Charged Niobium-Doped Silicon Clusters: Niobium Encapsulated in Silicon CagesXia, Xin Xin; Hermann, Andreas; Kuang, Xiao Yu; Jin, Yuan Yuan; Lu, Cheng; Xing, Xiao DongJournal of Physical Chemistry C (2016), 120 (1), 677-684CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We performed systematic structure searches for low energy structures of neutral and singly charged niobium-doped silicon clusters NbSinQ (n = 2-20; Q = 0, ± 1) by means of the CALYPSO structure searching method. A large population of low energy clusters is collected from the unbiased structure search. Subsequent geometry optimizations using d.-functional theory with the B3LYP exchange-correlation functional are carried out to det. structural patterns and relative stabilities of various low energy candidates for Nb-doped silicon clusters. Based on the calcd. binding energies along with measured photoelectron spectroscopy data, we are able to confirm that our lowest energy structures are the true min. It is shown that the localized position of the Nb impurity atom in NbSin0/±1 clusters gradually moves from the convex capping position, to surface-substituted, to the concave, and in the end to the encapsulated state as the no. of Si atoms increases from 2 to 20. The lowest energy isomer of both neutral and anionic NbSi12 cluster is very stable in a high-symmetry endohedral D6h structure in which the Nb atom is placed at the center of a regular hexagonal prism of Si atoms. This makes it an attractive building block for cluster-assembled materials.
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451Phi, N. D.; Trung, N. T.; Janssens, E.; Ngan, V. T. Electron counting rules for transition metal-doped Si12 clusters. Chem. Phys. Lett. 2016, 643, 103– 108, DOI: 10.1016/j.cplett.2015.11.025Google Scholar451https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFWqtrzI&md5=180087763a0945263ac46ef7e59e3498Electron counting rules for transition metal-doped Si12 clustersPhi, Nguyen Duy; Trung, Nguyen Tien; Janssens, Ewald; Ngan, Vu ThiChemical Physics Letters (2016), 643 (), 103-108CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Application of the phenomenol. shell model (PSM) provides an explanation for the enhanced stability of Si12Cr and Si12Fe clusters and relative cluster stability along the Si12M (M = Sc-Ni) series. Sequence of orbital shells in PSM is mostly detd. by the confining potential, which depends on the cluster shape. In D6h hexagonal prism geometry, degenerate 2P and 2D shells undergo splitting, and the energy levels of 2Pz and 2Dz2 orbitals become higher than those of (2Px, 2Py) and (2Dxy,2Dyz,2Dxz,2Dx2-y2), resp. Therefore, stability of the most stable Si12Cr and Si12Fe clusters is attributed to the filling of the 2S22P62D8 and 2S22P62D10 closed shells.
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452Hou, L.; Yang, J.; Liu, Y. Reexamination of structures, stabilities, and electronic properties of holmium-doped silicon clusters HoSin (n = 12–20). J. Mol. Model. 2016, 22, 193, DOI: 10.1007/s00894-016-3058-1Google Scholar452https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2s3lslyrtQ%253D%253D&md5=48aeb265a2d5d86b42e7743070a03817Reexamination of structures, stabilities, and electronic properties of holmium-doped silicon clusters HoSi n (n = 12-20)Hou Liyuan; Yang Jucai; Yang Jucai; Liu YumingJournal of molecular modeling (2016), 22 (8), 193 ISSN:.The total energies, growth patterns, equilibrium geometries, relative stabilities, hardnesses, intramolecular charge transfer, and magnetic moments of HoSi n (n = 12-20) clusters have been reexamined theoretically using two different density functional schemes in combination with relativistic small-core Stuttgart effective core potentials (ECP28MWB) for the Ho atoms. The results show that when n = 12-15, the most stable structures are predicted to be exohedral frameworks with a quartet ground state, but when n = 16-20, they are predicted to be endohedral frameworks with a sextuplet ground state. These trend in stability across the clusters (gauged from their dissociation energies) was found to be approximately the same regardless of the DFT scheme used in the calculations, with HoSi13, HoSi16, HoSi18, and HoSi20 calculated to be more stable than the other clusters. The results obtained for cluster hardness indicated that doping the Ho atom into Si13 and Si16 leads to the most stable HoSi n clusters, while doping Ho into the other Si n clusters increases the photochemical sensitivity of the cluster. Analyses of intracluster charge transfer and magnetic moments revealed that charge always shifts from the Ho atom to the Si n cluster during the creation of exohedral HoSi n (n = 12-15) structures. However, the direction of charge transfer is reversed during the creation of endohedral HoSi n (n = 16-20) structures, which implies that Ho acts as an electron acceptor when it is encapsulated in the Si n cage. Furthermore, when the most stable exohedral HoSi n (n = 12-15) structures are generated, the 4f electrons of Ho are virtually unchanged and barely participate in intracluster bonding. However, in the most stable endohedral HoSi n (n = 16-20) frameworks, a 4f electron does participate in bonding. It does this by transferring to the 5d orbital, which hybridizes with the 6s and 6p orbitals and then interacts with Si valence sp orbitals. Meanwhile, the total magnetic moments of the HoSi n (n = 16-20) clusters are considerably higher than those of HoSi n (n = 12-15). Interestingly, the endohedral HoSi16 and HoSi20 clusters can be viewed as the most suitable building blocks for novel high-density magnetic storage nanomaterials and for novel optical and optoelectronic photosensitive nanomaterials, respectively.
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453Lu, S.-J.; Cao, G.-J.; Xu, X.-L.; Xu, H.-G.; Zheng, W.-J. The structural and electronic properties of NbSin–/0 (n = 3–12) clusters: Anion photoelectron spectroscopy and ab initio calculations. Nanoscale 2016, 8, 19769– 19778, DOI: 10.1039/C6NR07480DGoogle Scholar453https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVWmtrjL&md5=455af6389689e9328f8bc9773f5775fcThe structural and electronic properties of NbSin-/0 (n = 3-12) clusters: anion photoelectron spectroscopy and ab initio calculationsLu, Sheng-Jie; Cao, Guo-Jin; Xu, Xi-Ling; Xu, Hong-Guang; Zheng, Wei-JunNanoscale (2016), 8 (47), 19769-19778CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Niobium-doped silicon clusters, NbSin- (n = 3-12), were generated by laser vaporization and investigated by anion photoelectron spectroscopy. The structures and electronic properties of NbSin- anions and their neutral counterparts were investigated with ab initio calcns. and compared with the exptl. results. It is found that the Nb atom in NbSin-/0 prefers to occupy the high coordination sites to form more Nb-Si bonds. The most stable structures of NbSi3-7-/0 are all exohedral structures with the Nb atom face-capping the Sin frameworks. At n = 8, both the anion and neutral adopt a boat-shaped structure and the openings of the boat-shaped structures remain unclosed in NbSi9-10-/0 clusters. The most stable structure of the NbSi11- anion is endohedral, while that of neutral NbSi11 is exohedral. The global min. of both the NbSi12- anion and neutral NbSi12 are D6h sym. hexagonal prisms with the Nb atom at the center. The perfect D6h sym. hexagonal prism of NbSi12- is electronically stable as it obeys the 18-electron rule and has a shell-closed electronic structure with a large HOMO-LUMO gap of 2.70 eV. The MO anal. of NbSi12- suggests that the delocalized Nb-Si12 ligand interactions may contribute to the stability of the D6h sym. hexagonal prism. The AdNDP anal. shows that the delocalized 2c-2e Si-Si bonds and multicenter-2e NbSin bonds are important for the structural stability of the NbSi12- anion.
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454Lu, S.-J.; Xu, X.-L.; Feng, G.; Xu, H.-G.; Zheng, W.-J. Structural and electronic properties of AuSin– (n = 4–12) clusters: Photoelectron spectroscopy and ab initio calculations. J. Phys. Chem. C 2016, 120, 25628– 25637, DOI: 10.1021/acs.jpcc.6b08598Google Scholar454https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1ylurfO&md5=9982875b6c75e822369800a01032db2eStructural and Electronic Properties of AuSin- (n = 4-12) Clusters: Photoelectron Spectroscopy and Ab Initio CalculationsLu, Sheng-Jie; Xu, Xi-Ling; Feng, Gang; Xu, Hong-Guang; Zheng, Wei-JunJournal of Physical Chemistry C (2016), 120 (44), 25628-25637CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)AuSin- (n = 4-12) clusters were produced with a laser vaporization source and investigated by photoelectron spectroscopy. The swarm-intelligence-based CALYPSO structure search method and ab initio DFT-B3LYP calcns. were employed to det. their ground-state structures. The results revealed that the most stable isomers of AuSin- (n = 4-12) cluster anions are all exohedral structures, in which the Au atom caps the vertex, edge, or surface of the bare Sin clusters. The endohedral and exohedral structures of neutral AuSi11 are nearly degenerate in energy. The most stable structure of neutral AuSi12 is endohedral. The growth mechanism of AuSin- cluster anions is compared with those of AuGen-, AgSin-, and CuSin- clusters. It implies that the bond strengths of Au-Si and Au-Ge play important roles in the formation of cage structures for AuSi12- and AuGe12-, while the different at. radii of coinage metals, different bond strengths, and the strong relativistic effect in Au atom are responsible for the different growth mechanisms of Si clusters doped with different coinage metals.
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455Feng, Y.; Yang, J. Stability and electronic properties of praseodymium-doped silicon clusters PrSin (n = 12–21). J. Mol. Model. 2017, 23, 180, DOI: 10.1007/s00894-017-3352-6Google Scholar455https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1crltlClug%253D%253D&md5=ded7d3450b7a7b5416af962b9a1f0c43Stability and electronic properties of praseodymium-doped silicon clusters PrSin (n = 12-21)Feng Yutong; Yang JucaiJournal of molecular modeling (2017), 23 (6), 180 ISSN:.The neutral PrSi n (n = 12-21) species considering various spin configurations were systematically studied using PBE0 and B3LYP schemes in combination with relativistic small-core potentials (ECP28MWB) for Pr atoms and cc-pVTZ basis set for Si atoms. The total energy, growth-pattern, equilibrium geometry, relative stability, hardness, charge transfer, and magnetic moments are calculated and discussed. The results reveal that when n < 20, the ground-state structure of PrSi n evaluated to be prolate clusters. Starting from n = 20, the ground-state structures of PrSi n are evaluated to be endohedral cagelike clusters. Although the relative stabilities based on various binding energies and different functional is different from each other, the consensus is that the PrSi13, PrSi16, PrSi18, and PrSi20 are more stable than the others, especially the PrSi20. Analyses of hardness show that introducing Pr into Si n (n = 12-21) elevates the photochemical sensitivity, especially for PrSi20. Calculated result of magnetic moment and charge transfer shows that the 4f electrons of Pr in the clusters are changed, especially in endohedral structures such as PrSi20, in which one electron transfers from 4f to 5d orbital. That is, the 4f electron of Pr in the clusters participates in bonding. The way to participate in bonding is that a 4f electron transfers to 5d orbital. Although the 4f electron of Pr atom participates in bonding, the total magnetic moment of PrSi n is equal to that of isolated Pr atom. The charge always transfers from Pr atom to Si n cluster for the ground state structures of PrSin (n = 12-19), but charge transfer is reverse for n ≥ 20. The largest charge transfer for endohedral structure reveals that the bonding between Pr and Si n is ionic in nature and very strong. The fullerenelike structure of PrSi20 is the most stable among all of these clusters and can act as the building blocks for novel functional nanotubes.
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456Jin, X.; Arcisauskaite, V.; McGrady, J. E. The structural landscape in 14-vertex clusters of silicon, M@Si14: When two bonding paradigms collide. Dalton Trans. 2017, 46, 11636– 11644, DOI: 10.1039/C7DT02257CGoogle Scholar456https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1yns7zL&md5=92a7ef20ad80819831be090e377bca10The structural landscape in 14-vertex clusters of silicon, M@Si14: when two bonding paradigms collideJin, Xiao; Arcisauskaite, Vaida; McGrady, John E.Dalton Transactions (2017), 46 (35), 11636-11644CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)The structural chem. of the title clusters has been the source of controversy in the computational literature because the identity of the most stable structure appears to be pathol. dependent on the chosen theor. model. The candidate structures include a D3h-sym. 'fullerene-like' isomer with 3-connected vertices (A), an 'arachno' architecture (B) and an octahedral isomer with high vertex connectivities typical of 'closo' electron-deficient clusters (C). The key to understanding these apparently very different structures is the fact that they make use of the limited electron d. available from the endohedral metal in very different ways. Early in the transition series the favored structure is the one that maximizes transfer of electron d. from the electropos. metal to the cage whereas for later metals it is the one that minimizes repulsions with the increasingly core-like d electrons. The varying role of the d electrons across the transition series leads directly to strong functional dependency, and hence to the controversy in the literature.
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457Zhao, R.-N.; Chen, R.; Lu, Z.-C.; Han, J.-G. Geometrical and electronic properties of nanosize semiconductor Pt2Sin (n = 10–20) material: A density functional theory investigation. Mater. Sci. Eng., B 2017, 226, 151– 157, DOI: 10.1016/j.mseb.2017.09.011Google Scholar457https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFCqsb3O&md5=be70481b24b749caeb4adb28207967e8Geometrical and electronic properties of nanosize semiconductor Pt2Sin (n = 10-20) material: A density functional theory investigationZhao, Run-Ning; Chen, Rui; Lu, Zi-Chen; Han, Ju-GuangMaterials Science & Engineering, B: Advanced Functional Solid-State Materials (2017), 226 (), 151-157CODEN: MSBTEK; ISSN:0921-5107. (Elsevier B.V.)Growth-pattern behaviors, relative stabilities, geometrical and electronic properties of nanosize Pt2Sin (n = 10-20) semiconductor material are investigated by using d. functional methods. Optimized geometries exhibit that transition metal Pt2 is doped on small-size opened cage-like silicon frame with n = 10-15 while Pt2 is encapsulated into close cage-like Si frame with n = 16-20; Based upon the calcd. relative stabilities, the particular stable Pt2Si16 unit is discovered. Furthermore, the dominant growth patterns of Pt2Sin (n = 10-20) are based upon the stable pentagonal prism PtSi10 unit. Interestingly, the crit. size of geometry transition with bimetal atoms being completely encapsulated into silicon frame is detd. to be 15. The calcd. natural population anal. shows that charges are transferred from Sin frames to Pt2 atoms. Addnl., Pt2Si19 cluster has the smallest HOMO-LUMO gap and the strongest chem. activity.
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458Liu, Y.; Yang, J.; Cheng, L. Structural stability and evolution of scandium-doped silicon clusters: Evolution of linked to encapsulated structures and its influence on the prediction of electron affinities for ScSin (n = 4–16) clusters. Inorg. Chem. 2018, 57, 12934– 12940, DOI: 10.1021/acs.inorgchem.8b02159Google Scholar458https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVSqtbnF&md5=ef420a6ef605d178d23484be09405231Structural Stability and Evolution of Scandium-Doped Silicon Clusters: Evolution of Linked to Encapsulated Structures and Its Influence on the Prediction of Electron Affinities for ScSin (n = 4-16) ClustersLiu, Yuming; Yang, Jucai; Cheng, LinInorganic Chemistry (2018), 57 (20), 12934-12940CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Sc-doped semiconductor clusters are the simplest transition metal- and rare-earth metal-doped semiconductor clusters. In this work, the structural evolution behavior and electronic properties of Sc-doped neutral and anionic Sin (n = 4-16) clusters were studied using the ABCluster global search technique coupled with a hybrid d. functional method. The results revealed that although neutral and anionic configurations are different for ScSin (n = 6-14) clusters, the evolution pattern of the ground-state structures is consistent (evolution of linked to encapsulated structures starting from n = 14). The good agreement between the theor. and exptl. photoelectron spectra demonstrated that the obtained anionic global min. structures are reasonable. The excellent agreement between the adiabatic electron affinities cor. by considering the structural correction factor and the exptl. data indicated that the structural correction factor is important for reproducing the exptl. data and that the obtained ground-state structures for the neutral ScSin clusters reported herein are reliable. The relative stability and chem. bonding anal. showed that the fully encapsulated ScSi16- cluster is a magic cluster with good thermodn. and chem. stability.
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459Bista, D.; Reber, A. C.; Chauhan, V.; Khanna, S. N. Electronic and magnetic properties of Fe2Sin (1 ≤ n ≤ 12)+/0/– clusters. Chem. Phys. Lett. 2018, 706, 113– 119, DOI: 10.1016/j.cplett.2018.05.079Google Scholar459https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtVyjsLrJ&md5=6d98ea3f581d0c227a83d121ad71db02Electronic and magnetic properties of Fe2Sin (1 ≤ n ≤ 12)+/0/- clustersBista, Dinesh; Reber, Arthur C.; Chauhan, Vikas; Khanna, Shiv N.Chemical Physics Letters (2018), 706 (), 113-119CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)First principles studies on the geometry, electronic structure and magnetic properties of neutral, cationic, and anionic Fe2Sin (1 ≤ n ≤ 12) have been performed to better understand magnetic dopants in silicon. The doubly-Fe doped clusters in the size range 1 ≤ n ≤ 12 are marked by finite spin moments at the Fe sites, and Fe2Si3, Fe2Si4, and Fe2Si7 are found to exhibit antiferromagnetic coupling. Fe2Si3 and Fe2Si12 are relatively stable. We find that short Fe-Fe bond distances correlate with ferromagnetic coupling due to the destabilization of antibonding orbitals between the iron sites, while longer Fe-Fe bond distances lead to nonbonding AOs that favor antiferromagnetic coupling.
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460Yang, B.; Xu, H.; Xu, X.; Zheng, W. Photoelectron spectroscopy and theoretical study of CrnSi15–n– (n = 1–3): Effects of doping Cr atoms on the structural and magnetic properties. J. Phys. Chem. A 2018, 122, 9886– 9893, DOI: 10.1021/acs.jpca.8b10588Google Scholar460https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlylt7rO&md5=5138f3745330c6e6139245064d061a53Photoelectron Spectroscopy and Theoretical Study of CrnSi15-n- (n = 1-3): Effects of Doping Cr Atoms on the Structural and Magnetic PropertiesYang, Bin; Xu, Hongguang; Xu, Xiling; Zheng, WeijunJournal of Physical Chemistry A (2018), 122 (51), 9886-9893CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)CrnSi15-n- (n = 1-3) clusters were investigated by using size-selected anion photoelectron spectroscopy combined with d. functional theory calcns. The results show that the most stable structure of CrSi14- is of C2v symmetry with the Cr atom encapsulated in a Si14 cage which can be viewed as a boat-shaped Si10 unit capped by four addnl. silicon atoms. A large HOMO-LUMO gap of neutral CrSi14 is confirmed based on the photoelectron spectrum of CrSi14- anion. Cr2Si13- has two isomers nearly degenerate in energy: one can be characterized as one Si atom interacting with a Cr2Si12 hexagonal prism while the other can be viewed as one Si atom capping a distorted Cr2Si12 hexagonal antiprism. Cr3Si12- has a D6d sym. wheel structure in which three Cr atoms form an axle surrounded by 12 Si atoms. The magnetic moments of CrSi14-, Cr2Si13-, and Cr3Si12- increase from 1 to 3μB and then to 7μB with the increasing no. of Cr atoms in the clusters. The magnetic moments of Cr2Si13- and Cr3Si12- are mainly contributed by the surface Cr atoms.
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461Wu, X.; Zhou, S.; Huang, X.; Chen, M.; Bruce King, R.; Zhao, J. Revisit of large-gap Si16 clusters encapsulating group-IV metal atoms (Ti, Zr, Hf). J. Comput. Chem. 2018, 39, 2268– 2272, DOI: 10.1002/jcc.25545Google Scholar461https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhslWju7vP&md5=8c3a547f0adda9d697e851e31218143fRevisit of large-gap Si16 clusters encapsulating group-IV metal atoms (Ti, Zr, Hf)Wu, Xue; Zhou, Si; Huang, Xiaoming; Chen, Maodu; Bruce King, R.; Zhao, JijunJournal of Computational Chemistry (2018), 39 (27), 2268-2272CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)Doped clusters by Si16 cage encapsulating group-IV metal atoms (M@Si16, M = Ti, Zr and Hf) are computationally investigated by both d. functional theory (DFT) and high-level CCSD(T) method. Their low-energy structures are globally searched using a genetic algorithm based on DFT. The ground state structures of neutral and anionic M@Si16 are detd. by calcg. the vertical and adiabatic detachment energies and comparing them with the exptl. data. For neutral Ti@Si16, the Frank-Kasper (FK) deltahedron with Td symmetry and distorted FK isomer with C3v symmetry are nearly degenerate as the ground state and may coexist in lab., while the distorted FK isomer is the most probable structure for Ti@Si16- anion. For neutral and anionic Zr@Si16 and Hf@Si16 clusters, the ground states at finite temps. up to 300 K are the fullerene-like D4d bitruncated square trapezohedron. These theor. results establish a more complete picture for the most stable structures of M@Si16 clusters, which possess large gaps and may serve as building blocks for electronic and optoelectronic applications.
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462Lu, S.-J.; Wu, L.-S.; Lin, F. Probing the structures and properties of Ti2Si20–/0 clusters by density functional theory calculations. Chem. Phys. Lett. 2018, 707, 108– 112, DOI: 10.1016/j.cplett.2018.07.048Google Scholar462https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsVSms7vK&md5=6ecaae956c4137f9aa1033a952c4f6b8Probing the structures and properties of Ti2Si-/020 clusters by density functional theory calculationsLu, Sheng-Jie; Wu, Li-Shun; Lin, FengChemical Physics Letters (2018), 707 (), 108-112CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We present a theor. investigation on the structures and properties of Ti2Si-/020 clusters using d. functional theory calcns. The results showed that the global min. of both anionic and neutral Ti2Si20 adopt a C2h sym. double hexagonal prisms stacked structure with the two Ti atoms encapsulated inside the silicon cage. Bond length, Wiberg bond order, const. electronic charge d., and MO analyses suggest that the Ti-Ti interactions in Ti2Si-/020 are weak. Interestingly, Ti2Si-/020 exhibit significant 3D aromaticity, which play important roles in their structural stability.
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463Lu, S.-J. Exploring the structural evolution and electronic properties of medium-sized Nb2Sin–/0 (n= 13–20) clusters by density functional theory calculations. Chem. Phys. Lett. 2018, 713, 58– 64, DOI: 10.1016/j.cplett.2018.10.028Google Scholar463https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvFWqu73F&md5=06f95ebc604b34247dfa9583d222f6a5Exploring the structural evolution and electronic properties of medium-sized Nb2Sin-/0 (n = 13-20) clusters by density functional theory calculationsLu, Sheng-JieChemical Physics Letters (2018), 713 (), 58-64CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We present a theor. investigation on the structural evolution and electronic properties of Nb2Sin-/0 (n = 13-20) clusters. The two Nb atoms tend to stay close and occupy the high coordination sites. Their most stable structures can be described as a central axis of Nb-Nb bond surrounded by the Sin frameworks. The structural evolution between Nb2Sin- anions and Nb2Sin neutrals is markedly different. Nb2Si19- is found to be the crit. size of forming Nb2-endohedral structure for anionic clusters, whereas the Nb2-endohedral structure forms at n = 20 for neutral clusters.
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464Lu, S.-J.; Wu, L.-S.; Lin, F. Probing the geometric structures and bonding properties in Nb2Si20–/0 clusters by density functional theory calculations. Chem. Phys. Lett. 2018, 709, 60– 64, DOI: 10.1016/j.cplett.2018.08.041Google Scholar464https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsF2gsbvO&md5=de58ada367efab737dc9ad9a028fb47dProbing the geometric structures and bonding properties in Nb2Si-/020 clusters by density functional theory calculationsLu, Sheng-Jie; Wu, Li-Shun; Lin, FengChemical Physics Letters (2018), 709 (), 60-64CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We present a theor. investigation on the geometric structures and bonding properties of Nb2Si20-/0 clusters using d. functional theory calcns. The results showed that Nb2Si20- anion has an irregular Nb2-doped endohedral structure, whereas Nb2Si20 neutral adopts C2h sym. elongated dodecahedron cage structure, which is composed of twelve pentagonal faces. Bond length, Wiberg bond order, const. electronic charge d., and MO analyses suggest that the Nb-Nb interactions in Nb2Si20-/0 are strong. Interestingly, Nb2Si20-/0 exhibit significant 3D aromaticity.
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465Lu, S.-J. Exploring the structural and electronic properties of double-Fe atom-doped Si20 cluster by quantum chemical calculations. Theor. Chem. Acc. 2019, 138, 48, DOI: 10.1007/s00214-019-2438-xGoogle ScholarThere is no corresponding record for this reference.
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466Yang, B.; Xu, X.-L.; Xu, H.-G.; Farooq, U.; Zheng, W.-J. Structural evolution and electronic properties of CoSin– (n = 3–12) clusters: Mass-selected anion photoelectron spectroscopy and quantum chemistry calculations. Phys. Chem. Chem. Phys. 2019, 21, 6207– 6215, DOI: 10.1039/C8CP07734GGoogle Scholar466https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXjtlWgur4%253D&md5=c934f8dcdefd6ceac7a5c641c8569ed3Structural evolution and electronic properties of CoSin- (n = 3-12) clusters: mass-selected anion photoelectron spectroscopy and quantum chemistry calculationsYang, Bin; Xu, Xi-Ling; Xu, Hong-Guang; Farooq, Umar; Zheng, Wei-JunPhysical Chemistry Chemical Physics (2019), 21 (11), 6207-6215CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structural and electronic properties of cobalt-doped silicon clusters, CoSin- (n = 3-12), are investigated using mass-selected anion photoelectron spectroscopy combined with quantum chem. calcns. The crit. size from an exohedral to an endohedral structure of the anionic clusters is n = 9 and that of the neutral ones is n = 10. Natural population anal. shows transfer of electrons from the silicon framework to the Co atom. The total magnetic moments of CoSi3- and CoSi4- clusters are 2μB, while those of CoSin- (n = 5-12) clusters are 0μB. The exptl. measurements show that CoSi10- has the highest vertical detachment energy among all the CoSin- (n = 3-12) clusters in the current study. The theor. calcns. show that CoSi10- has a C3v sym. tetracapped trigonal prism structure and very large HOMO-LUMO gap. Both exptl. and theor. results imply that CoSi10- has unusual stability. Its special stability is attributed to its highly sym. structure and closed-shell MO configuration. The structure of neutral CoSi10 has relatively lower symmetry as compared to that of CoSi10- due to Jahn-Teller distortion.
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467Majumder, C.; Kulshreshtha, S. Impurity-doped Si10 cluster: Understanding the structural and electronic properties from first-principles calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 245426, DOI: 10.1103/PhysRevB.70.245426Google Scholar467https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXislOlug%253D%253D&md5=c0629e5e81430a526851dc786cfa3021Impurity-doped Si10 cluster: understanding the structural and electronic properties from first-principles calculationsMajumder, Chiranjib; Kulshreshtha, S. K.Physical Review B: Condensed Matter and Materials Physics (2004), 70 (24), 245426/1-245426/7CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Structural and electronic properties of metal-doped silicon clusters (MSi10, M = Li, Be, B, C, Na, Mg, Al, and Si) have been investigated via ab initio mol. dynamics simulation under the formalism of the d. functional theory. The exchange-correlation energy has been calcd. using the generalized gradient approxn. method. Several stable isomers of MSi10 clusters have been identified based on different initial configurations and their relative stabilities have been analyzed. The location of the impurity atom depends on the nature of interaction between the impurity atom and the host cluster and the size of the impurity atom. Whereas Be and B atoms form stable isomers, the impurity atom being placed at the center of the bicapped tetragonal antiprism structure of the Si10 cluster, all other elements diffuse outside the cage of Si10 cluster. To understand the stability and the chem. bonding, the LCAO-MO based all electron calcns. have been carried out for the lowest energy isomers using the hybrid B3LYP energy functional. Based on the interaction energy of the M atoms with Si10 clusters it is found that p-p interaction dominates over the s-p interaction and smaller size atoms interact more strongly. Based on the binding energy, the relative stability of MSi10 clusters is found to follow the order of CSi10 > BSi10 > BeSi10 > Si11 > AlSi10 > LiSi10 > NaSi10 > MgSi10, leading one to infer that while the substitution of C, B and Be enhances the stability of the Si11 cluster, others have an opposite effect. The extra stability of the BeSi10 clusters is due to its encapsulated close packed structure and large energy gap between the HOMO and LUMO energy levels.
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468Sporea, C.; Rabilloud, F. Stability of alkali-encapsulating silicon cage clusters. J. Chem. Phys. 2007, 127, 164306, DOI: 10.1063/1.2790018Google Scholar468https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXht12jsLjN&md5=b83b9112801e558709e6a534e3449910Stability of alkali-encapsulating silicon cage clustersSporea, C.; Rabilloud, F.Journal of Chemical Physics (2007), 127 (16), 164306/1-164306/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report a DFT-B3LYP computational study of the possibility to form alkali-encapsulating Si clusters A@Sin with n = 10-20. We predict and quantify the stability for lithium, sodium, and potassium atoms encapsulated in silicon cage. The structure and electronic properties are discussed. An electronic charge transfer from the alkali atom to the Sin cage is obsd. The A@Sin cluster is formed of a pos. charge located on the alkali surrounded by a neg. one distributed on the whole Si cage. For each size the predicted stability of such structure is discussed and compared with that of surface-bound alkali isomers. The alkali-encapsulating Si clusters A@Sin are found to be stable but lying much higher in energy as compared to surface-bound alkali isomers.
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469Hossain, D.; Hagelberg, F.; Pittman, C. U.; Saebo, S. Structures and stabilities of clusters of Si12, Si18, and Si20 containing endohedral charged and neutral atomic species. J. Phys. Chem. C 2007, 111, 13864– 13871, DOI: 10.1021/jp0735839Google Scholar469https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXpsFyhsbY%253D&md5=91b663136b1cc58ff59be99e29e8d663Structures and Stabilities of Clusters of Si12, Si18, and Si20 Containing Endohedral Charged and Neutral Atomic SpeciesHossain, Delwar; Hagelberg, Frank; Pittman, Charles U., Jr.; Saebo, SveinJournal of Physical Chemistry C (2007), 111 (37), 13864-13871CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Electronic structure calcns. based on DFT-B3LYP and MP2 methods were performed on three isomers of Si12 and on the endohedral clusters Si12 contg. neutral or charged at. species. The existence of endohedral clusters depends on the Si12 cage shape and the nature of the embedding species. Endohedral clusters of Li0,1,-1, Na0,1,-1, and He in Si12 cages were found. In contrast, K+, Ne, F-, or Cl- do not form endohedral clusters with Si12 due to their large size. All endohedral clusters that are min. on the potential energy surfaces are stable and have large HOMO-LUMO gaps ( > 1 eV). The stability order for the lithium and sodium clusters is: anionic clusters > neutral clusters > cationic clusters. The endohedral complex of two Li atoms with the Si18 cage is lower in energy than the sum of the empty Si18 cage and two Li atoms. In contrast, doping two Na atoms into the Si18 cage forms an exohedral Na2Si18 cluster. An endohedral cluster of Li2 with Si20 was also investigated and characterized. The stability of the endohedral complexes of two Li atoms in Si18 and Si20 suggest that silicon nanotubes, which are unstable, might be stabilized by an internal string of Li atoms.
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470Avaltroni, F.; Steinmann, S. N.; Corminboeuf, C. How are small endohedral silicon clusters stabilized?. Phys. Chem. Chem. Phys. 2012, 14, 14842– 14849, DOI: 10.1039/c2cp42097jGoogle Scholar470https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFersrrK&md5=ed91d06eb503e9d5d616ecda05ef271bHow are small endohedral silicon clusters stabilized?Avaltroni, Fabrice; Steinmann, Stephan N.; Corminboeuf, ClemencePhysical Chemistry Chemical Physics (2012), 14 (43), 14842-14849CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Clusters in the (Be, B, C)@Sin(0,1,2+) (n = 6-10) series, isoelectronic to Sin2-, present multiple sym. structures, including rings, cages and open structures, which the doping atom stabilizes using contrasting bonding mechanisms. The most striking feature of these clusters is the absence of electron transfer (for Be) or even the inversion (for B and C) in comparison to classic endohedral metallofullerenes (e.g. from the outer frameworks towards the enclosed atom). The relatively small cavity of the highly sym. Si8 cubic cage benefits more strongly from the encapsulation of a boron atom than from the insertion of a too large beryllium atom. Overall, the maximization of multicenter-type bonding, as visualized by the Localized Orbital Locator (LOL), is the key to the stabilization of the small Sin cages. Boron offers the best balance between size, electronegativity and delocalized bonding pattern when compared to beryllium and carbon.
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471Lu, S.-J.; Xu, X.-L.; Cao, G.-J.; Xu, H.-G.; Zheng, W.-J. Structural evolution of B2Sin–/0 (n = 3–12) clusters: Size-selected anion photoelectron spectroscopy and theoretical calculations. J. Phys. Chem. C 2018, 122, 2391– 2401, DOI: 10.1021/acs.jpcc.7b10906Google Scholar471https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjsVKhug%253D%253D&md5=40a504c850fc6c04700c805e43e1236eStructural Evolution of B2Sin-/0 (n = 3-12) Clusters: Size-Selected Anion Photoelectron Spectroscopy and Theoretical CalculationsLu, Sheng-Jie; Xu, Xi-Ling; Cao, Guo-Jin; Xu, Hong-Guang; Zheng, Wei-JunJournal of Physical Chemistry C (2018), 122 (4), 2391-2401CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structural evolution of B2Sin-/0 (n = 3-12) clusters were studied by anion photoelectron spectroscopy and ab initio calcns. The 2 B atoms in B2Si3-12-/0 incline to form a B-B bond and more B-Si bonds. The lowest-lying isomers of B2Si3-/0 have planar structures, while those of B2Si4-7-/0 primarily adopt bowl-shaped based geometries. The 2 B atoms in B2Si8-9-/0 are not completely encapsulated into the Sin cages. For B2Si10-/0, the 2 B atoms are completely encapsulated inside the Si10 cage to form a distorted pentagonal prismatic structure. B2Si10-/0 exhibits 3D aromaticity and B2Si10 neutral has σ + π double delocalized bonding patterns. B2Si11- anion has an endohedral polyhedral cage-like structure, whereas B2Si11 neutral adopts a bicapped pentagonal prismatic structure with only one interior B atom. The structures of anionic and neutral B2Si12 are endohedral tetracapped tetragonal prisms. It is interesting that 2 Si5 5-membered rings are stabilized by 2 B atoms in B2Si10-/0, while the stabilization of 2 Si6 6-membered rings by 2 B atoms is not obsd. in B2Si12-/0.
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472Borshch, N.; Berestnev, K.; Pereslavtseva, N.; Kurganskii, S. Geometric structure and electron spectrum of YSin– clusters (n = 6–17). Phys. Solid State 2014, 56, 1276– 1281, DOI: 10.1134/S1063783414060080Google Scholar472https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXpvFGqur4%253D&md5=1181d59a28af085fb0ecb69db6f37123Geometric structure and electron spectrum of YSi-n clusters (n = 6-17)Borshch, N. A.; Berestnev, K. S.; Pereslavtseva, N. S.; Kurganskii, S. I.Physics of the Solid State (2014), 56 (6), 1276-1281CODEN: PSOSED; ISSN:1063-7834. (SP MAIK Nauka/Interperiodica)Results of the optimization of the geometric structure of YSi-n anion clusters (n = 6-17) have been presented and their electron spectra have been calcd. Calcns. have been performed by the d. functional theory method. Actual geometric structures of clusters have been established by comparing the calcd. and known exptl. data.
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473Trivedi, R.; Bandyopadhyay, D. Evolution of electronic and vibrational properties of M@Xn (M = Ag, Au, X = Ge, Si, n = 10, 12, 14) clusters: A density functional modeling. J. Mater. Sci. 2018, 53, 8263– 8273, DOI: 10.1007/s10853-018-2002-4Google Scholar473https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjvVOmurk%253D&md5=cfd4e33c0bf4b24d44f343b5c8834542Evolution of electronic and vibrational properties of M@Xn (M = Ag, Au, X = Ge, Si, n = 10, 12, 14) clusters: a density functional modelingTrivedi, Ravi; Bandyopadhyay, DebashisJournal of Materials Science (2018), 53 (11), 8263-8273CODEN: JMTSAS; ISSN:0022-2461. (Springer)Evolution of electronic and vibrational properties of M@Xn (M = Ag, Au, X = Ge, Si, n = 10, 12, 14) nanoclusters is investigated by using first-principle d. functional theory (DFT)-based calcns. with effective core potentials. To explain the thermodn. and chem. stability of the ground state cluster in each size, variation of different thermodn. and chem. parameters, like, binding energy (BE), HOMO-LUMO gap (ΔE), vertical ionization potential (VIP) and vertical electron affinity (VEA) was studied with the variation of the size of the clusters for emphasizing the differences and similarities in the clusters. It is found that Au doping in Ge and Si cages prefers endohedral position, whereas Ag prefers to take the position at the surface of the cages. In addn., IR and Raman spectra of the clusters are also studied to understand the vibrational nature of the stable clusters. At the end, present theor. results are compared with existing exptl. data. Theor. knowledge of the thermodn., chem. and vibrational properties of these specific ground state structures is important for understanding its potential application in the field of optoelectronic science.
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474Ngan, V. T.; Pierloot, K.; Nguyen, M. T. Mn@Si14+: A singlet fullerene-like endohedrally doped silicon cluster. Phys. Chem. Chem. Phys. 2013, 15, 5493– 5498, DOI: 10.1039/c3cp43390kGoogle Scholar474https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXkt1GgtLs%253D&md5=2917f3d717838e3c769e3b76f809c62cMn@Si14+: a singlet fullerene-like endohedrally doped silicon clusterNgan, Vu Thi; Pierloot, Kristine; Nguyen, Minh ThoPhysical Chemistry Chemical Physics (2013), 15 (15), 5493-5498CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The electronic structure of Mn@Si14+ is detd. using DFT and CASPT2/CASSCF(14,15) computations with large basis sets. The endohedrally Mn-doped Si cationic cluster has a D3h fullerene-like structure featuring a closed-shell singlet ground state with a singlet-triplet gap of ∼1 eV. A strong stabilizing interaction occurs between the 3d(Mn) and the 2D-shell(Si14) orbitals, and a large amt. of charge is transferred from the Si14 cage to the Mn dopant. The 3d(Mn) orbitals are filled by encapsulation, and the magnetic moment of Mn is completely quenched. Full occupation of [2S, 2P, 2D] shell orbitals by 18 delocalized electrons confers the doped Mn@Si14+ cluster a spherically arom. character.
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475Li, Y.; Tam, N. M.; Woodham, A. P.; Lyon, J. T.; Li, Z.; Lievens, P.; Fielicke, A.; Nguyen, M. T.; Janssens, E. Structure dependent magnetic coupling in cobalt-doped silicon clusters. J. Phys. Chem. C 2016, 120, 19454– 19460, DOI: 10.1021/acs.jpcc.6b06320Google Scholar475https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht12jsLjF&md5=d6903790e6be51602e2454e41a41bd56Structure Dependent Magnetic Coupling in Cobalt-Doped Silicon ClustersLi, Yejun; Tam, Nguyen Minh; Woodham, Alex P.; Lyon, Jonathan T.; Li, Zhe; Lievens, Peter; Fielicke, Andre; Nguyen, Minh Tho; Janssens, EwaldJournal of Physical Chemistry C (2016), 120 (34), 19454-19460CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structure of cobalt-doped silicon clusters, SinCo+ (n = 5-8) and SinCo2+ (n = 8-12), is investigated in a combined IR multiple photon dissocn. spectroscopy and d. functional theory study. The singly doped clusters have exohedral structures in which the Co atom substitutes an atom of bare Sin+1+ clusters. In the doubly doped SinCo2+ clusters, the second Co atom is adsorbed to the singly doped counterparts and, for n ≥ 9, one of the Co atoms is encapsulated by a silicon cage. Computational anal. of the electronic and magnetic properties of the identified isomers indicates a distance dependent magnetic coupling between the Co atoms in the SinCo2+ clusters.
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476Gao, Y.; Zeng, X. C. M4@Si28 (M = Al, Ga): Metal-encapsulated tetrahedral silicon fullerene. J. Chem. Phys. 2005, 123, 204325, DOI: 10.1063/1.2121568Google Scholar476https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtlGiu7%252FN&md5=51c4ca0336ac80a0ad6e073cd7f60a9bM4@Si28 (M = Al, Ga): Metal-encapsulated tetrahedral silicon fullereneGao, Yi; Zeng, X. C.Journal of Chemical Physics (2005), 123 (20), 204325/1-204325/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)It is known that silicon fullerenes cannot maintain perfect cage structures like carbon fullerenes. Previous d.-functional theory calcns. have shown that even with encapsulated species, nearly all endohedral silicon fullerenes exhibit highly puckered cage structures in comparison with their carbon counterparts. In this work, we present theor. evidences that the tetrahedral fullerene cage Si28 can be fully stabilized by encapsulating a tetrahedral metallic cluster (Al4 or Ga4). To our knowledge, this is the first predicted endohedral silicon fullerene that can retain perfectly the same cage structure (without puckering) as the carbon fullerene counterpart (Td-C28 fullerene). D.-functional theory calcns. also suggest that the two endohedral metallo-silicon fullerenes Td-M4@Si28 (M = Al and Ga) can be chem. stable because both clusters have a large HOMO-LUMO energy gap (∼0.9 eV), strong spherical aromaticity (nucleus-independent chem. shift value of -36 and -44), and large binding and embedding energies.
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477Hagelberg, F.; Yanov, I.; Leszczynski, J. Theoretical investigations on closed-shell silicon clusters doped with Cu atoms. J. Mol. Struct.: THEOCHEM 1999, 487, 183– 192, DOI: 10.1016/S0166-1280(99)00153-0Google Scholar477https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXlslelt7s%253D&md5=c89b488d5837f435c6e2b5869112686fTheoretical investigations on closed-shell silicon clusters doped with Cu atomsHagelberg, F.; Yanov, I.; Leszczynski, J.Journal of Molecular Structure: THEOCHEM (1999), 487 (1-2), 183-192CODEN: THEODJ; ISSN:0166-1280. (Elsevier Science B.V.)Silicon clusters doped with a single Cu impurity (CuSin), which were detected previously by mass spectrometric expt., were explored by means of ab initio ROHF anal. Features related to geometries, stabilities and adsorption energies of the species CuSin, n = 4, 6, 8, 10, 12, 14, are discussed. The sensitive dependence of the phys. properties of CuSin clusters on the geometric arrangement of the resp. Sin subsystem is emphasized.
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478Pederson, M. R.; Jackson, K. A. Variational mesh for quantum-mechanical simulations. Phys. Rev. B: Condens. Matter Mater. Phys. 1990, 41, 7453– 7461, DOI: 10.1103/PhysRevB.41.7453Google Scholar478https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sfkvFyjtA%253D%253D&md5=5aa04fa8685ae5d3e40b350f850396d7Variational mesh for quantum-mechanical simulationsPederson; JacksonPhysical review. B, Condensed matter (1990), 41 (11), 7453-7461 ISSN:0163-1829.There is no expanded citation for this reference.
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479Porezag, D.; Pederson, M. R. Optimization of Gaussian basis sets for density-functional calculations. Phys. Rev. A: At., Mol., Opt. Phys. 1999, 60, 2840– 2847, DOI: 10.1103/PhysRevA.60.2840Google Scholar479https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmt1Ohs70%253D&md5=79c70934d1b43f39816b4ad83ddee42bOptimization of Gaussian basis sets for density-functional calculationsPorezag, Dirk; Pederson, Mark R.Physical Review A: Atomic, Molecular, and Optical Physics (1999), 60 (4), 2840-2847CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)We introduce a scheme for the optimization of Gaussian basis sets for use in d.-functional calcns. It is applicable to both all-electron and pseudopotential methodologies. In contrast to earlier approaches, the no. of primitive Gaussians (exponents) used to define the basis functions is not fixed but adjusted, based on a total-energy criterion. Furthermore, all basis functions share the same set of exponents. The numerical results for the scaling of the shortest-range Gaussian exponent as a function of the nuclear charge are explained by anal. derivations. We have generated all-electron basis sets for H, B through F, Al, Si, Mn, and Cu. They efficiently and accurately reproduce structural properties and binding energies for a variety of clusters and mols. for both local and gradient-cor. d. functionals.
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480Jaeger, J.; Jaeger, T.; Duncan, M. Photodissociation of metal–silicon clusters: Encapsulated versus surface-bound metal. J. Phys. Chem. A 2006, 110, 9310– 9314, DOI: 10.1021/jp0629947Google Scholar480https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmslGrs7Y%253D&md5=4e06d5e93ab1beeb94aa54aaa9ecd5b5Photodissociation of Metal-Silicon Clusters: Encapsulated versus Surface-Bound MetalJaeger, J. B.; Jaeger, T. D.; Duncan, M. A.Journal of Physical Chemistry A (2006), 110 (30), 9310-9314CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Metal-silicon cluster cations of the form MSin+ (M = Cu, Ag, Cr) are produced in a mol. beam with pulsed laser vaporization. These species are mass-selected in a reflectron time-of-flight spectrometer and studied with laser photodissocn. at 532 and 355 nm. For the noble metals copper and silver, photodissocn. of the n = 7 and 10 clusters proceeds primarily by the loss of metal atoms, indicating that the metal is not located within the interior of silicon cages, and that metal-silicon bonding is weaker than silicon-silicon bonding. Chromium-silicon clusters for n = 7 also lose primarily the metal atom, but at n = 15 and 16 these dissoc. via the loss of silicon, producing smaller metal-silicon species. This behavior is consistent with stronger metal-silicon bonding and encapsulated metal structures, as suggested previously by theory. MSi6+ cations are produced efficiently in all of these photodissocn. processes, indicating that these species have enhanced stability compared to other small clusters. Improved values are obtained for the ionization potentials of Si7 and Si10.
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481Negishi, A.; Kariya, N.; Sugawara, K.-i.; Arai, I.; Hiura, H.; Kanayama, T. Size-selective formation of tungsten cluster-containing silicon cages by the reactions of Wn+ (n = 1–5) with SiH4. Chem. Phys. Lett. 2004, 388, 463– 467, DOI: 10.1016/j.cplett.2004.03.036Google Scholar481https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjtVShsrg%253D&md5=786a3e4818cd5668e617542c44f9a3feSize-selective formation of tungsten cluster-containing silicon cages by the reactions of Wn+ (n = 1-5) with SiH4Negishi, Akihiro; Kariya, Naoki; Sugawara, Ko-ichi; Arai, Ichiro; Hiura, Hidefumi; Kanayama, ToshihikoChemical Physics Letters (2004), 388 (4-6), 463-467CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The reactions of tungsten clusters, W+n (n = 1-5), with silane and their sequential reactions were investigated using FTICR mass spectrometry. It was found that the Si or SiH2 addn. to the clusters, accompanied by H2 release, occurred for every collision with silane and then suddenly stopped at the specific silicon atom nos. of m: m = 12 for n = 1, m = 17 and 18 for n = 2, m = 22 for n = 3, m = 25 and 26 for n = 4 and m = 29 for n = 5. These values coincide with the surrounding atom nos. of a simple close packing model, suggesting the formation of stable silicon cages encapsulating tungsten clusters.
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482Kaneko, T.; Takaya, H.; Hatakeyama, R. Generation of argon-ion mixed silicon plasmas forming argon encapsulated silicon clusters. Appl. Phys. Lett. 2006, 89, 241501, DOI: 10.1063/1.2404606Google Scholar482https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXislGktg%253D%253D&md5=6d13e2633ba5189a43cb89ccab8ddfddGeneration of argon-ion mixed silicon plasmas forming argon encapsulated silicon clustersKaneko, T.; Takaya, H.; Hatakeyama, R.Applied Physics Letters (2006), 89 (24), 241501/1-241501/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)An inductively coupled argon (Ar) plasma is superimposed on a silicon (Si) plasma generated by an electron beam gun to realize the formation of gas-atom encapsulated Si cage clusters. The Si clusters, which are formed and deposited on a substrate, are analyzed by laser-desorption time-of-flight mass spectrometry and have the mass spectra of not only pure Si cluster (Sin; n = 1-17) but also Si cluster doped with Ar atom (ArSin; n = 10-20) in the case that the large amt. of Ar ions is generated in addn. to the Si plasma. Together with the anal. of XPS, the Ar atom is included in the Si cluster, forming the structure of endohedral Ar@Sin complexes. Also, the mass spectrum of Ar@Sin indicates the existence of the magic numbered cluster size n = 15, 16 similar to the metal encapsulated Si clusters.
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483Neukermans, S.; Wang, X.; Veldeman, N.; Janssens, E.; Silverans, R.; Lievens, P. Mass spectrometric stability study of binary MSn clusters (S = Si, Ge, Sn, Pb, and M = Cr, Mn, Cu, Zn). Int. J. Mass Spectrom. 2006, 252, 145– 150, DOI: 10.1016/j.ijms.2005.12.056Google Scholar483https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XktVygtbg%253D&md5=86163df1a62d249b6fd37e96e3a577e0Mass spectrometric stability study of binary MSn clusters (S=Si, Ge, Sn, Pb, and M=Cr, Mn, Cu, Zn)Neukermans, S.; Wang, X.; Veldeman, N.; Janssens, E.; Silverans, R. E.; Lievens, P.International Journal of Mass Spectrometry (2006), 252 (2), 145-150CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)The authors present a mass spectrometric stability study of metal doped Group IVA (semi-) metal clusters. Binary metal (M) doped semi-metal (S) MSn (S = Si, Ge, Sn, Pb, and M = Cr, Mn, Cu, Zn) clusters are produced using a dual-target, dual-laser vaporization source and mass analyzed using a reflectron time-of-flight mass spectrometer. The resulting abundance spectra reveal host and dopant dependent stability information for the different systems studied. From a comparison between the exptl. abundance information and computational studies available in literature, the enhanced abundance of several sizes is interpreted in terms of peculiarly stable dopant-encapsulated cagelike structures.
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484Janssens, E.; Gruene, P.; Meijer, G.; Wöste, L.; Lievens, P.; Fielicke, A. Argon physisorption as structural probe for endohedrally doped silicon clusters. Phys. Rev. Lett. 2007, 99, 063401, DOI: 10.1103/PhysRevLett.99.063401Google Scholar484https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXovFGrtLc%253D&md5=bc31e8ef470ac5fd73b74bb0b91b1778Argon Physisorption as Structural Probe for Endohedrally Doped Silicon ClustersJanssens, Ewald; Gruene, Philipp; Meijer, Gerard; Woste, Ludger; Lievens, Peter; Fielicke, AndrePhysical Review Letters (2007), 99 (6), 063401/1-063401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report on an element-dependent crit. size for argon physisorption at 80 K on transition-metal-doped silicon clusters. Argon does not attach to elemental silicon clusters but only to surface-located transition-metal atoms. Thus physisorption provides structural information. Specifically, the minimal cluster size for the formation of endohedral singly metal-doped silicon cages has been detd. The obsd. crit. size for doubly doped silicon clusters indicates that larger caged mols. can be formed, eventually leading to the growth of metal-doped silicon nanorods.
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485Ohara, M.; Miyajima, K.; Pramann, A.; Nakajima, A.; Kaya, K. Geometric and electronic structures of terbium–silicon mixed clusters (TbSin; 6 ≤ n ≤ 16). J. Phys. Chem. A 2002, 106, 3702– 3705, DOI: 10.1021/jp012952cGoogle Scholar485https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XhvVGrsb8%253D&md5=ab317874d4e2b8ad2c2f12393050a3f3Geometric and Electronic Structures of Terbium-Silicon Mixed Clusters (TbSin; 6 ≤ n ≤ 16)Ohara, M.; Miyajima, K.; Pramann, A.; Nakajima, A.; Kaya, K.Journal of Physical Chemistry A (2002), 106 (15), 3702-3705CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The geometric and the electronic structures of terbium-silicon anions, TbSin- (6 ≤ n ≤ 16) were investigated by using photoelectron spectroscopy (PES) and a chem.-probe method. The clusters were produced by a double-rod laser vaporization technique. From trends obsd. in the electron affinities (EAs), the TbSin- clusters were categorized into three groups of (I) 6 ≤ n ≤ 9, (II) n = 10, 11, and (III) n ≥ 12. Together with adsorption reactivity toward H2O it is concluded that a Tb atom is encapsulated inside a Sin cage at n ≥ 10; Tb@Sin.
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486Koyasu, K.; Atobe, J.; Akutsu, M.; Mitsui, M.; Nakajima, A. Electronic and geometric stabilities of clusters with transition metal encapsulated by silicon. J. Phys. Chem. A 2007, 111, 42– 49, DOI: 10.1021/jp066757fGoogle Scholar486https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlSgs7jN&md5=cb52754f7efb8dae369a13c27ecf6bf8Electronic and Geometric Stabilities of Clusters with Transition Metal Encapsulated by SiliconKoyasu, Kiichirou; Atobe, Junko; Akutsu, Minoru; Mitsui, Masaaki; Nakajima, AtsushiJournal of Physical Chemistry A (2007), 111 (1), 42-49CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Silicon clusters mixed with a transition metal atom, MSin, were generated by a double-laser vaporization method, and the electronic and geometric stabilities for the resulting clusters with transition metal encapsulated by silicon were examd. exptl. By means of a systematic doping with transition metal atoms of groups 3, 4, and 5 (M = Sc, Y, Lu, Ti, Zr, Hf, V, Nb, and Ta), followed by changes of charge states, we explored the use of an electronic closing of a silicon caged cluster and variations in its cavity size to facilitate metal-atom encapsulation. Results obtained by mass spectrometry, anion photoelectron spectroscopy, and adsorption reactivity toward H2O show that the neutral cluster doped with a group 4 atom features an electronic and a geometric closing at n = 16. The MSi16 cluster with a group 4 atom undergoes an electronic change in (i) the no. of valence electrons when the metal atom is substituted by the neighboring metals with a group 3 or 5 atom and in (ii) at. radii with the substitution of the same group elements of Zr and Hf. The reactivity of a halogen atom with the MSi16 clusters reveals that VSi16F forms a superatom complex with ionic bonding.
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487Koyasu, K.; Atobe, J.; Furuse, S.; Nakajima, A. Anion photoelectron spectroscopy of transition metal-and lanthanide metal-silicon clusters: MSin– (n= 6–20). J. Chem. Phys. 2008, 129, 214301, DOI: 10.1063/1.3023080Google Scholar487https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsVKqsr3P&md5=d72830880fc9e49d2f80ab73b85f679cAnion photoelectron spectroscopy of transition metal- and lanthanide metal-silicon clusters: MSin- (n = 6-20)Koyasu, Kiichirou; Atobe, Junko; Furuse, Shunsuke; Nakajima, AtsushiJournal of Chemical Physics (2008), 129 (21), 214301/1-214301/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic properties of Si clusters contg. a transition or lanthanide metal atom from Group 3, 4, or 5, MSin, (M = Sc, Ti, V, Y, Zr, Nb, Lu, Tb, Ho, Hf, and Ta) were studied by anion photoelectron spectroscopy at 213 nm. In the case of the group 3 elements Sc, Y, Lu, Tb, and Ho, the threshold energy of electron detachment exhibits local maxima at n = 10 and 16, while in case of the group 4 elements Ti, Zr, and Hf, the threshold energy exhibits a local min. at n = 16, assocd. with the presence of a small bump in the spectrum. These electronic characteristics of MSin are closely related to a cooperative effect between their geometric and electronic structures, which is discussed, together with the results of expts. that probe their geometric stability via their reactivity to H2O adsorption, and with theor. calcns. (c) 2008 American Institute of Physics.
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488Shibuta, M.; Ohta, T.; Nakaya, M.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Chemical characterization of an alkali-like superatom consisting of a Ta-encapsulating Si16 cage. J. Am. Chem. Soc. 2015, 137, 14015– 14018, DOI: 10.1021/jacs.5b08035Google Scholar488https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhslOrt77O&md5=a5a3521c93079e4ccc0de7aa88c0d065Chemical Characterization of an Alkali-Like Superatom Consisting of a Ta-Encapsulating Si16 CageShibuta, Masahiro; Ohta, Tsutomu; Nakaya, Masato; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiJournal of the American Chemical Society (2015), 137 (44), 14015-14018CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Chem. characterization was performed for an alkali-like superatom consisting of a Ta-encapsulating Si16 cage, Ta@Si16, deposited on a graphite substrate using XPS to element-specifically clarify the local electronic structure of the cage atoms. The XPS spectra derived from Ta 4f and Si 2p core levels were well modeled with a single chem. component, revealing the formation of a sym. Si cage around the Ta atom in the deposited nanoclusters. On chem. treatments by heating or O2 exposure, the deposited Ta@Si16 is thermally stable up to 700 K and is also exceptionally less reactive toward O2 compared to other Ta-Si nanoclusters, although some heat degrdn. and oxidn. accompany the treatments. These results show the promising possibility of applying Ta@Si16 as a building block to fabricate cluster-assembled materials consisting of naked nanoclusters.
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489Tsunoyama, H.; Shibuta, M.; Nakaya, M.; Eguchi, T.; Nakajima, A. Synthesis and characterization of metal-encapsulating Si16 cage superatoms. Acc. Chem. Res. 2018, 51, 1735– 1745, DOI: 10.1021/acs.accounts.8b00085Google Scholar489https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXosFKhsb8%253D&md5=2d2edfd1250704f9f9d473b293408cc9Synthesis and characterization of metal-encapsulating Si16 cage superatomsTsunoyama, Hironori; Shibuta, Masahiro; Nakaya, Masato; Eguchi, Toyoaki; Nakajima, AtsushiAccounts of Chemical Research (2018), 51 (8), 1735-1745CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)Nanoclusters, aggregates of several to hundreds of atoms, have been one of the central issues of nanomaterials sciences owing to their unique structures and properties, which could be found neither in nanoparticles with several nanometer diams. nor in organometallic complexes. Along with the chem. nature of each element, properties of nanoclusters change dramatically with size parameters, making nanoclusters strong potential candidates for future tailor-made materials; these nanoclusters are expected to have attractive properties such as redox activity, catalysis, and magnetism. Alloying of nanoclusters addnl. gives designer functionality by fine control of their electronic structures in addn. to size parameters. Among binary nanoclusters, binary cage superatoms (BCSs) composed of transition metal (M) encapsulating silicon cages, M@Si16, have unique cage structures of 16 silicon atoms, which have not been found in elemental silicon nanoclusters, organosilicon compds., and silicon based clathrates. The unique compn. of these BCSs originates from the simultaneous satisfaction of geometric and electronic shell-closings in terms of cage geometry and valence electron filling, where a total of 68 valence electrons occupy the superat. orbitals of (1S)2(1P)6(1D)10(1F)14(2S)2(1G)18(2P)6(2D)10 for M = group 4 elements in neutral ground state. The most important issue for M@Si16 BCSs is fine-tuning of their characters by replacement of the central metal atoms, M, based on one-by-one adjustment of valence electron counts in the same structure framework of Si16 cage; the replacement of M yields a series of M@Si16 BCSs, based on their superat. characteristics. So far, despite these unique features probed in the gas-phase mol. beam and predicted by quantum chem. calcns., M@Si16 have not yet been isolated.In this Account, we have focused on recent advances in synthesis and characterizations of M@Si16 BCSs (M = Ti and Ta). A series of M@Si16 BCSs (M = groups 3 to 5) was found in gas-phase mol. beam expts. by photoelectron spectroscopy and mass spectrometry: formation of halogen-, rare-gas-, and alkali-like superatoms was identified through one-by-one tuning of no. of total valence electrons. Toward future functional materials in the solid state, we have developed an intensive, size-selected nanocluster source based on high-power impulse magnetron sputtering coupled with a mass spectrometer and a soft-landing app. With scanning probe microscopy and photoelectron spectroscopy, the structure of surface-immobilized BCSs has been elucidated; BCSs can be dispersed in an isolated form using C60 fullerene decoration of the substrate. The intensive nanocluster source also enables the synthesis of BCSs in the 100-mg scale by coupling with a direct liq.-embedded trapping method into org. dispersants, enabling their structure characterization as a highly sym. "metal-encapsulating tetrahedral silicon-cage" (METS) structure with Frank-Kasper geometry.
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490Zheng, W.; Nilles, J. M.; Radisic, D.; Bowen, K. H., Jr Photoelectron spectroscopy of chromium-doped silicon cluster anions. J. Chem. Phys. 2005, 122, 071101, DOI: 10.1063/1.1851984Google Scholar490https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhsFWgtbs%253D&md5=b8d8ba782eca04ab4aa852117719ee60Photoelectron spectroscopy of chromium-doped silicon cluster anionsZheng, Weijun; Nilles, J. Michael; Radisic, Dunja; Bowen, Kit H., Jr.Journal of Chemical Physics (2005), 122 (7), 071101/1-071101/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The photoelectron spectra of Cr-doped Si cluster anions, CrSin-, were measured over the size range, n = 8-12. Their vertical detachment energies are 2.71, 2.88, 2.87, 2.95, and 3.18 eV, resp. The results support theor. calcns. by S.N. Khanna et al. (2002) which found CrSi12 to be an enhanced stability (magic) cluster with its Cr atom encapsulated inside a Si cage and with its magnetic moment completely quenched by the effects of the surrounding cage.
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491Grubisic, A.; Wang, H.; Ko, Y. J.; Bowen, K. H. Photoelectron spectroscopy of europium-silicon cluster anions, EuSin– (3 ⩽ n ⩽ 17). J. Chem. Phys. 2008, 129, 054302, DOI: 10.1063/1.2963500Google Scholar491https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXpslSrsrk%253D&md5=cfa4c29190eac71b7897b99d85b151ddPhotoelectron spectroscopy of europium-silicon cluster anions, EuSin- (3≤n≤17)Grubisic, Andrej; Wang, Haopeng; Ko, Yeon Jae; Bowen, Kit H.Journal of Chemical Physics (2008), 129 (5), 054302/1-054302/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The photoelectron spectra are reported of EuSin- cluster anions (3≤n≤17). They reveal dramatic electronic rearrangements over the size range n = 10-12. In particular, a marked increase in the adiabatic electron affinity of EuSi12 (2.8 eV) compared to its stoichiometric neighbor, EuSi11 (1.9 eV), is obsd. Probably a significant geometric reorganization due to the encapsulation of a Eu atom occurs in this size range and is responsible for the detected changes in the electronic structure. In light of this interpretation, EuSi12 is the smallest fully endohedral Eu-Si cluster. (c) 2008 American Institute of Physics.
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492Grubisic, A.; Ko, Y. J.; Wang, H.; Bowen, K. H. Photoelectron spectroscopy of lanthanide–silicon cluster anions LnSin– (3 ≤ n ≤ 13; Ln = Ho, Gd, Pr, Sm, Eu, Yb): Prospect for magnetic silicon-based clusters. J. Am. Chem. Soc. 2009, 131, 10783– 10790, DOI: 10.1021/ja805205rGoogle Scholar492https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXotFKnsbg%253D&md5=ef63566d6275627065e204b3a2fdb45aPhotoelectron Spectroscopy of Lanthanide-Silicon Cluster Anions LnSin- (3 ≤ n ≤ 13; Ln = Ho, Gd, Pr, Sm, Eu, Yb): Prospect for Magnetic Silicon-Based ClustersGrubisic, Andrej; Ko, Yeon Jae; Wang, Haopeng; Bowen, Kit H.Journal of the American Chemical Society (2009), 131 (30), 10783-10790CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Photoelectron spectroscopy was used to study a variety of LnSin- cluster anions (Ln = Yb, Eu, Sm, Gd, Ho, Pr; 3 ≤ n ≤ 13). For a particular size n, the measured valence electronic transitions of all these systems fall into either one of two categories, reflecting the influence of the different oxidn. states of the lanthanide atoms involved. In one, the spectra of YbSin- and EuSin- are nearly identical to each other, while in the other the spectra of GdSin-, HoSin-, and PrSin- are essentially identical. SmSin- clusters exhibit an intermediate behavior with smaller clusters resembling the former category and larger clusters resembling the latter category. In the intermediate size range, 7 ≤ n ≤ 10, for SmSin- both categories appear to be present, with one matching the EuSin--like systems and the other HoSin--like clusters. The distinction between LnSin- categories strongly correlates with the oxidn. state of the particular lanthanide as usually found in its compds. Among the Ln-Si clusters studied herein, Yb, Eu, and in case of Sm, sizes n ≥ 10, adopt a nominal +2 oxidn. state while Ho, Pr, Gd, and in case of Sm, sizes n ≤ 7, exhibit a nominal +3 oxidn. state. Also, dramatic increases in adiabatic electron affinity values obsd. at n = 10 for the LnIIISin series and at n = 12 for the LnIISin series were attributed to an inherent electronic stabilization of those particular clusters, rather than to the lanthanides' encapsulation. The obsd. limited effect of f-electrons on the valence electronic structure and thus on bonding in LnSin- clusters may leave these electrons available for inducing magnetism. Consequently, Ln@Sin clusters may hold promise as building blocks of Si-based cluster materials with magnetic properties.
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493Zamudio-Bayer, V.; Leppert, L.; Hirsch, K.; Langenberg, A.; Rittmann, J.; Kossick, M.; Vogel, M.; Richter, R.; Terasaki, A.; Möller, T. Coordination-driven magnetic-to-nonmagnetic transition in manganese-doped silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2013, 88, 115425, DOI: 10.1103/PhysRevB.88.115425Google Scholar493https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslCjtb7I&md5=04da0052e860fb119c3c38a2197092cbCoordination-driven magnetic-to-nonmagnetic transition in manganese-doped silicon clustersZamudio-Bayer, V.; Leppert, L.; Hirsch, K.; Langenberg, A.; Rittmann, J.; Kossick, M.; Vogel, M.; Richter, R.; Terasaki, A.; Moeller, T.; Issendorff, B. V.; Kuemmel, S.; Lau, T.Physical Review B: Condensed Matter and Materials Physics (2013), 88 (11), 115425/1-115425/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The interaction of a single manganese impurity with silicon is analyzed in a combined exptl. and theor. study of the electronic, magnetic, and structural properties of manganese-doped silicon clusters. The structural transition from exohedral to endohedral doping coincides with 3d electron delocalization and a quenching of high-spin states. For all geometric structures investigated, we find a correlation of the magnetic moment with the manganese coordination no. and nearest-neighbor distance. This observation can be generalized to manganese point defects in bulk silicon, whose magnetic moments fall within the obsd. magnetic-to-nonmagnetic transition, and therefore react very sensitively to changes in the local geometry. The results indicate that high-spin states in manganese-doped silicon could be stabilized by an appropriate lattice expansion.
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494Lau, J.; Vogel, M.; Langenberg, A.; Hirsch, K.; Rittmann, J.; Zamudio-Bayer, V.; Möller, T.; Issendorff, B. v. Communication: Highest occupied molecular orbital–lowest unoccupied molecular orbital gaps of doped silicon clusters from core level spectroscopy. J. Chem. Phys. 2011, 134, 041102, DOI: 10.1063/1.3547699Google Scholar494https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVOhu7o%253D&md5=cd30c4b54a8ba0e1e8f9c1f820abe87cHighest occupied molecular orbital-lowest unoccupied molecular orbital gaps of doped silicon clusters from core level spectroscopyLau, J. T.; Vogel, M.; Langenberg, A.; Hirsch, K.; Rittmann, J.; Zamudio-Bayer, V.; Moeller, T.; von Issendorff, B.Journal of Chemical Physics (2011), 134 (4), 041102/1-041102/3CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A method to det. band gaps of size-selected and isolated nanoparticles by combination of valence band and core-level photoionization spectroscopy is presented. This approach is widely applicable and provides a convenient alternative to current std. techniques for the detn. of band gaps by optical or photoelectron spectroscopy. A 1st application to V doped Si clusters confirms a striking size-dependence of their HOMO-LUMO gaps. (c) 2011 American Institute of Physics.
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495Ngan, V. T.; Gruene, P.; Claes, P.; Janssens, E.; Fielicke, A.; Nguyen, M. T.; Lievens, P. Disparate effects of Cu and V on structures of exohedral transition metal-doped silicon clusters: A combined far-infrared spectroscopic and computational study. J. Am. Chem. Soc. 2010, 132, 15589– 15602, DOI: 10.1021/ja105099uGoogle Scholar495https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlWmtLnI&md5=f87ef1c6f559f14b034fcb85418bd2ffDisparate Effects of Cu and V on Structures of Exohedral Transition Metal-Doped Silicon Clusters: A Combined Far-Infrared Spectroscopic and Computational StudyNgan, Vu Thi; Gruene, Philipp; Claes, Pieterjan; Janssens, Ewald; Fielicke, Andre; Nguyen, Minh Tho; Lievens, PeterJournal of the American Chemical Society (2010), 132 (44), 15589-15602CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The growth mechanisms of small cationic silicon clusters contg. up to 11 Si atoms, exohedrally doped by V and Cu atoms, are described. We find that as dopants, V and Cu follow two different paths: while V prefers substitution of a silicon atom in a highly coordinated position of the cationic bare silicon clusters, Cu favors adsorption to the neutral or cationic bare clusters in a lower coordination site. The different behavior of the two transition metals becomes evident in the structures of SinM+ (n = 4-11 for M = V, and n = 6-11 for M = Cu), which are investigated by d. functional theory and, for several sizes, confirmed by comparison with their exptl. vibrational spectra. The spectra are measured on the corresponding SinM+·Ar complexes, which can be formed for the exohedrally doped silicon clusters. The comparison between exptl. and calcd. spectra indicates that the BP86 functional is suitable to predict far-IR spectra of these clusters. In most cases, the calcd. IR spectrum of the lowest-lying isomer fits well with the expt., even when various isomers and different electronic states are close in energy. However, in a few cases, namely Si9Cu+, Si11Cu+, and Si10V+, the exptl. verified isomers are not the lowest in energy according to the d. functional theory calcns., but their structures still follow the described growth mechanism. The different growth patterns of the two series of doped Si clusters reflect the role of the transition metal's 3d orbitals in the binding of the dopant atoms.
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496Claes, P.; Janssens, E.; Ngan, V.; Gruene, P.; Lyon, J. T.; Harding, D. J.; Fielicke, A.; Nguyen, M.; Lievens, P. Structural identification of caged vanadium doped silicon clusters. Phys. Rev. Lett. 2011, 107, 173401, DOI: 10.1103/PhysRevLett.107.173401Google Scholar496https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVWks77O&md5=d8499d24e44c5f191810042b974e852eStructural Identification of Caged Vanadium Doped Silicon ClustersClaes, P.; Janssens, E.; Ngan, V. T.; Gruene, P.; Lyon, J. T.; Harding, D. J.; Fielicke, A.; Nguyen, M. T.; Lievens, P.Physical Review Letters (2011), 107 (17), 173401/1-173401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)The geometry of cationic silicon clusters doped with vanadium, SinV+ (n=12-16), is investigated by using IR multiple photon dissocn. of the corresponding rare gas complexes in combination with ab initio calcns. It is shown that the clusters are endohedral cages, and evidence is provided that Si16V+ is a fluxional system with a sym. Frank-Kasper geometry.
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497Ngan, V. T.; Janssens, E.; Claes, P.; Lyon, J. T.; Fielicke, A.; Nguyen, M. T.; Lievens, P. High magnetic moments in manganese-doped silicon clusters. Chem. - Eur. J. 2012, 18, 15788– 15793, DOI: 10.1002/chem.201201839Google Scholar497https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFGktrvO&md5=bfea1498f58aaf3b222e7652b4f9a05bHigh Magnetic Moments in Manganese-Doped Silicon ClustersNgan, Vu Thi; Janssens, Ewald; Claes, Pieterjan; Lyon, Jonathan T.; Fielicke, Andre; Nguyen, Minh Tho; Lievens, PeterChemistry - A European Journal (2012), 18 (49), 15788-15793, S15788/1-S15788/27CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors report on the structural, electronic, and magnetic properties of manganese-doped silicon clusters cations, SinMn+ with n = 6-10, 12-14, and 16, using mass spectrometry and IR spectroscopy in combination with d. functional theory computations. This combined exptl. and theor. study allows several structures to be identified. All the exohedral SinMn+ (n = 6-10) clusters are substitutive derivs. of the bare Sin+1+ cations, while the endohedral SinMn+ (n = 12-14 and 16) clusters adopt fullerene-like structures. The hybrid B3P86 functional is appropriate in predicting the ground electronic states of the clusters and in reproducing their IR spectra. The clusters turn out to have high magnetic moments localized on Mn. In particular the Mn atoms in the exohedral SinMn+ (n = 6-10) clusters have local magnetic moments of 4 μB or 6 μB and can be considered as magnetic copies of the silicon atoms. Opposed to other 3d transition-metal dopants, the local magnetic moment of the Mn atom is not completely quenched when encapsulated in a silicon cage.
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498Li, X.; Claes, P.; Haertelt, M.; Lievens, P.; Janssens, E.; Fielicke, A. Structural determination of niobium-doped silicon clusters by far-infrared spectroscopy and theory. Phys. Chem. Chem. Phys. 2016, 18, 6291– 6300, DOI: 10.1039/C5CP07298KGoogle Scholar498https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2gt7o%253D&md5=81196e72d0614b441554e50fc79c77f0Structural determination of niobium-doped silicon clusters by far-infrared spectroscopy and theoryLi, Xiaojun; Claes, Pieterjan; Haertelt, Marko; Lievens, Peter; Janssens, Ewald; Fielicke, AndrePhysical Chemistry Chemical Physics (2016), 18 (8), 6291-6300CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures of cationic clusters SinNb+ n = 4-12 are detd. using the combination of IR multiple photon dissocn., IR-MPD, and d. functional theory DFT calcns. The exptl. IR-MPD spectra of the argon complexes of SinNb+ are assigned by comparison to the calcd. IR spectra of low-energy structures of SinNb+ that are identified using the stochastic 'random kick' algorithm in conjunction with the BP86 GGA functional. It is found that the Nb dopant tends to bind in an apex position of the Sin framework for n = 4-9 and in surface positions with high coordination nos. for n = 10-12. For the larger doped clusters, it is suggested that multiple isomers coexist and contribute to the exptl. spectra. The structural evolution of SinNb+ clusters is similar to V-doped silicon clusters J. Am. Chem. Soc., 2010, 132, 15589-15602, except for the largest size investigated n = 12, since V takes an endohedral position in Si12V+. The interaction with a Nb atom, with its partially unfilled 4d orbitals leads to a significant stability enhancement of the Sin framework as reflected, e.g. by high binding energies and large HOMO-LUMO gaps.
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499Li, Y.; Tam, N. M.; Claes, P.; Woodham, A. P.; Lyon, J. T.; Ngan, V. T.; Nguyen, M. T.; Lievens, P.; Fielicke, A.; Janssens, E. Structure assignment, electronic properties, and magnetism quenching of endohedrally doped neutral silicon clusters, SinCo (n = 10–12). J. Phys. Chem. A 2014, 118, 8198– 8203, DOI: 10.1021/jp500928tGoogle Scholar499https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXms1Wgtbs%253D&md5=db4c69f5ca8ceff99f529da91c96870aStructure Assignment, Electronic Properties, and Magnetism Quenching of Endohedrally Doped Neutral Silicon Clusters, SinCo (n = 10-12)Li, Yejun; Tam, Nguyen Minh; Claes, Pieterjan; Woodham, Alex P.; Lyon, Jonathan T.; Ngan, Vu Thi; Nguyen, Minh Tho; Lievens, Peter; Fielicke, Andre; Janssens, EwaldJournal of Physical Chemistry A (2014), 118 (37), 8198-8203CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The structures of neutral cobalt-doped silicon clusters have been assigned by a combined exptl. and theor. study. Size-selective IR spectra of neutral SinCo (n = 10-12) clusters are measured using a tunable IR-UV two-color ionization scheme. The exptl. IR spectra are compared with calcd. spectra of low-energy structures predicted at the B3P86 level of theory. It is shown that the SinCo (n = 10-12) clusters have endohedral caged structures, where the silicon frameworks prefer double-layered structures encapsulating the Co atom. Electronic structure anal. indicates that the clusters are stabilized by an ionic interaction between the Co dopant atom and the silicon cage due to the charge transfer from the silicon valence sp orbitals to the cobalt 3d orbitals. Strong hybridization between the Co dopant atom and the silicon host quenches the local magnetic moment on the encapsulated Co atom.
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500Cheshnovsky, O.; Yang, S.; Pettiette, C.; Craycraft, M.; Liu, Y.; Smalley, R. Ultraviolet photoelectron spectroscopy of semiconductor clusters: Silicon and germanium. Chem. Phys. Lett. 1987, 138, 119– 124, DOI: 10.1016/0009-2614(87)80353-6Google ScholarThere is no corresponding record for this reference.
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501Hoffmann, M. A.; Wrigge, G.; Issendorff, B. v.; Müller, J.; Ganteför, G.; Haberland, H. Ultraviolet photoelectron spectroscopy of Si4 to Si1000. Eur. Phys. J. D 2001, 16, 9– 11, DOI: 10.1007/s100530170048Google Scholar501https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXosV2gurk%253D&md5=0a8e383e449d3fc99936af63b003885fUltraviolet photoelectron spectroscopy of Si4- to Si1000-Hoffmann, M. Astruc; Wrigge, G.; von Issendorff, B.; Muller, J.; Gantefor, G.; Haberland, H.European Physical Journal D: Atomic, Molecular and Optical Physics (2001), 16 (1-3), 9-11CODEN: EPJDF6; ISSN:1434-6060. (Springer-Verlag)Using a new exptl. setup the authors have measured UV (hv = 6.4 eV) photoelectron spectra of cold Si cluster anions Sin- in a very broad size range. For sizes up to n = 46 the spectra exhibit rich structures. For larger sizes only smooth spectra were obtained. No trace of a bandgap was found even for clusters with >1000 atoms.
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502Meloni, G.; Ferguson, M. J.; Sheehan, S. M.; Neumark, D. M. Probing structural transitions of nanosize silicon clusters via anion photoelectron spectroscopy at 7.9 eV. Chem. Phys. Lett. 2004, 399, 389– 391, DOI: 10.1016/j.cplett.2004.10.030Google Scholar502https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVShsr3P&md5=d276e3824c872d1730b3981df152a6d1Probing structural transitions of nanosize silicon clusters via anion photoelectron spectroscopy at 7.9 eVMeloni, Giovanni; Ferguson, Michael J.; Sheehan, Sean M.; Neumark, Daniel M.Chemical Physics Letters (2004), 399 (4-6), 389-391CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Photoelectron spectra of silicon cluster anions as large as Si35- have been obtained with vacuum UV radiation at 157 nm (7.9 eV). The data show spectroscopic trends consistent with the structural transformation from prolate to more spherical clusters previously obsd. in ion mobility expts. In addn., we observe signal at high electron binding energy that may be analogous to the second band seen in the photoemission spectrum of bulk silicon.
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503Akola, J.; Manninen, M.; Häkkinen, H.; Landman, U.; Li, X.; Wang, L.-S. Photoelectron spectra of aluminum cluster anions: Temperature effects and ab initio simulations. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 60, R11297– R11300, DOI: 10.1103/PhysRevB.60.R11297Google Scholar503https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmvFOhu7g%253D&md5=3f597dd6157f3604bc0c37dd9f3a6cdePhotoelectron spectra of aluminum cluster anions: Temperature effects and ab initio simulationsAkola, Jaakko; Manninen, Matti; Hakkinen, Hannu; Landman, Uzi; Li, Xi; Wang, Lai-ShengPhysical Review B: Condensed Matter and Materials Physics (1999), 60 (16), R11297-R11300CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Photoelectron (PES) spectra from Al cluster anions, Aln- (12 ≤ n ≤ 15), at various temp. regimes, were studied using ab initio mol. dynamics simulations and exptl. The calcd. PES spectra, obtained via shifting of the simulated electronic densities of states by the self-consistently detd. values of the asymptotic exchange-correlation potential, agree well with the measured ones, allowing reliable structural assignments and theor. estn. of the clusters' temps.
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504Honea, E.; Ogura, A.; Peale, D.; Felix, C.; Murray, C.; Raghavachari, K.; Sprenger, W.; Jarrold, M.; Brown, W. Structures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopy. J. Chem. Phys. 1999, 110, 12161– 12172, DOI: 10.1063/1.479153Google Scholar504https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXjsFWjt78%253D&md5=d326e8fdd1574b7e2726c25dd053080bStructures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopyHonea, E. C.; Ogura, A.; Peale, D. R.; Felix, C.; Murray, C. A.; Raghavachari, K.; Sprenger, W. O.; Jarrold, M. F.; Brown, W. L.Journal of Chemical Physics (1999), 110 (24), 12161-12172CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures and coalescence behavior of size-selected, matrix-isolated silicon clusters have been studied using surface-plasmon-polariton (SPP) enhanced Raman spectroscopy. The cluster ions were produced in a laser vaporization source, mass selected then deposited into a co-condensed matrix of Ar, Kr or N2 on a liq. He cooled substrate. Raman spectra from monodisperse samples of the smaller clusters studied, Si4, Si6 and Si7, show sharp, well-resolved, vibrations which are in good agreement with predictions based on ab initio calcns. From these comparisons it was confirmed that Si4 is a planar rhombus, and assign Si6 as a distorted octahedron and Si7 as a pentagonal bipyramid. Si5 depositions down to 5 eV did not reveal a measurable Raman spectrum under our exptl. conditions. Evidence for cluster-cluster aggregation (or fragmentation) was obsd. under some conditions, even for a "magic no." cluster such as Si6. The spectra of the aggregated small clusters were identical to those obsd. for directly deposited larger cluster "bands," such as Si25-35. The Raman spectra of the aggregated clusters bear some similarity to those of bulk amorphous silicon. Cluster-deposited thin films were prepd. by sublimating the matrix material. Even under these "soft landing" conditions, changes in the Raman spectrum are obsd. with the thin films showing even greater similarity to amorphous silicon.
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505Pichierri, F.; Kumar, V.; Kawazoe, Y. Exohedral functionalization of the icosahedral cluster Si20H20: A density functional theory study. Chem. Phys. Lett. 2004, 383, 544– 548, DOI: 10.1016/j.cplett.2003.11.087Google Scholar505https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXpvF2ns78%253D&md5=1767bed9d7d2650e1e11e8925c45f457Exohedral functionalization of the icosahedral cluster Si20H20: a density functional theory studyPichierri, Fabio; Kumar, Vijay; Kawazoe, YoshiyukiChemical Physics Letters (2004), 383 (5,6), 544-548CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)D. functional theory calcns. on three derivs. of the recently predicted hydrogenated Si fullerene cluster Si20H20 using the B3PW91 hybrid exchange-correlation functional with the 6-311 + G(d) basis set is reported. The cluster was exohedrally functionalized by replacing one of its H atoms with -CH2OH, -COOH, and -CONH2. The resulting functionalized clusters have nearly the same HOMO-LUMO gaps as that of the perhydrogenated Si fullerene leading to the possibility of developing new Si fullerene-based mols. for medico-biol. applications. The deprotonated Si20H19(COO-) cluster displays a very large permanent dipole moment along with a strongly localized HOMO on its carboxyl group.
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506Pichierri, F.; Kumar, V.; Kawazoe, Y. Encapsulation of halide anions in perhydrogenated silicon fullerene: X–@Si20H20 (X= F, Cl, Br, I). Chem. Phys. Lett. 2005, 406, 341– 344, DOI: 10.1016/j.cplett.2005.02.121Google Scholar506https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjtF2gsbg%253D&md5=d48aa75c1c7c435252a9a8b900264364Encapsulation of halide anions in perhydrogenated silicon fullerene: X-@Si20H20 (X=F, Cl, Br, I)Pichierri, Fabio; Kumar, Vijay; Kawazoe, YoshiyukiChemical Physics Letters (2005), 406 (4-6), 341-344CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We report the results of a d. functional study of the encapsulation of halide anions into the dodecahedral cage of the perhydrogenated silicon fullerene Si20H20. The HOMO-LUMO energy gap of the endohedral complexes X-@Si20H20 (X = F, Cl, Br, I) is only ∼0.5 eV larger than that computed for the empty fullerene. The amt. of charge that is being transferred from the encapsulated anion to the fullerene increases from F- (∼10%) to I- ( > 70%). Only the encapsulation of Br- does not alter the cage thus indicating that this spherical anion might be employed in the anion-templated synthesis of the elusive Si20H20 cluster.
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507Tillmann, J.; Wender, J. H.; Bahr, U.; Bolte, M.; Lerner, H. W.; Holthausen, M. C.; Wagner, M. One-Step synthesis of a [20] silafullerane with an endohedral chloride ion. Angew. Chem., Int. Ed. 2015, 54, 5429– 5433, DOI: 10.1002/anie.201412050Google Scholar507https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkvF2ms7c%253D&md5=644a3970c6a0c5152dc3e18bb98dd94bOne-Step Synthesis of a [20]Silafullerane with an Endohedral Chloride IonTillmann, Jan; Wender, Josef Heinrich; Bahr, Ute; Bolte, Michael; Lerner, Hans-Wolfram; Holthausen, Max C.; Wagner, MatthiasAngewandte Chemie, International Edition (2015), 54 (18), 5429-5433CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Silicon analogs of the most prominent carbon nanostructures, namely, hollow spheroidals such as C60 and the fullerene family, have been unknown to date. Herein authors show that discrete Si20 dodecahedra, stabilized by an endohedral guest and valence satn., are accessible in preparative yields through a chloride-induced disproportionation reaction of hexachlorodisilane in the presence of tri(n-butyl)amine. X-ray crystallog. revealed that each silicon dodecahedron contains an endohedral chloride ion that imparts a net neg. charge. Eight chloro substituents and twelve trichlorosilyl groups are attached to the surface of each cluster in a strictly regioregular arrangement, a thermodynamically preferred substitution pattern according to quantum-chem. assessment. The results demonstrate that the wet-chem. self-assembly of a complex, monodisperse Si nanostructure is possible under mild conditions starting from simple Si2 building blocks.
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508Wigner, E.; Witmer, E. Über die struktur der zweiatomigen molekelspektren nach der quantenmechanik. Eur. Phys. J. A 1928, 51, 859– 886, DOI: 10.1007/BF01400247Google ScholarThere is no corresponding record for this reference.
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509Nolas, G. S. The physics and chemistry of inorganic clathrates; Springer: Dordrecht, 2014.Google ScholarThere is no corresponding record for this reference.
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510Emsley, J. The elements; Oxford University Press: New York, 1991.Google ScholarThere is no corresponding record for this reference.
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511He, J.; Wu, K.; Sa, R.; Li, Q.; Wei, Y. (Hyper) polarizabilities and optical absorption spectra of MSi12 clusters (M = Sc–Zn): A theoretical study. Chem. Phys. Lett. 2010, 490, 132– 137, DOI: 10.1016/j.cplett.2010.03.038Google Scholar511https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkvVertLY%253D&md5=36f9f898236fa03461083e3d321bdf9d(Hyper)polarizabilities and optical absorption spectra of MSi12 clusters (M=Sc-Zn): A theoretical studyHe, Jiangang; Wu, Kechen; Sa, Rongjian; Li, Qiaohong; Wei, YongqinChemical Physics Letters (2010), 490 (4-6), 132-137CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The dipole polarizabilities, 2nd-order hyperpolarizabilities, and optical absorption spectra of MSi12 clusters (M = Sc-Zn) were studied by using the (time-dependent) d. functional theory. The correlation functional exerts more remarkable influence on the dipole polarizability and 2nd-order hyperpolarizability calcns. than the exchange term. Referring to MP2 results, B3LYP provides poorer dipole polarizabilities but more reliable 2nd-order hyperpolarizabilities than B3PW91 and mPW1PW91 functionals. Addnl., the tunable (hyper)polarizabilities and optical absorption spectra were evidently obsd., which are attributed to the strong hybridization between 3d orbitals of M and 3s, 3p states of Si.
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512Kong, L.; Chelikowsky, J. R. Transport properties of transition-metal-encapsulated Si cages. Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 073401, DOI: 10.1103/PhysRevB.77.073401Google Scholar512https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtFaqtrs%253D&md5=cfb9acc96819b25f6a70a67942e10c81Transport properties of transition-metal-encapsulated Si cagesKong, Lingzhu; Chelikowsky, James R.Physical Review B: Condensed Matter and Materials Physics (2008), 77 (7), 073401/1-073401/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We performed d. functional pseudopotential calcns. of the spin-dependent transport through transition-metal-atom-encapsulated Si cages Si12X (X = Mn, Fe, and Co). The effect of the metal atom on conductance is studied. Mn- and Fe-doped systems show highly spin-polarized transmission whereas the magnetization in Co-doped system is quenched. Electrons are transferred from Si atoms into the minority d orbitals of the metal atoms. The conductance decreases as these electrons become localized around the encapsulated atoms.
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513Kawamura, H.; Kumar, V.; Kawazoe, Y. Water adsorption on Ti-doped silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 193402, DOI: 10.1103/PhysRevB.70.193402Google Scholar513https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVGhu77K&md5=05b1a2b0573369f608ca0b3b4c10df99Water adsorption on Ti-doped silicon clustersKawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 70 (19), 193402/1-193402/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Ab initio calcns. were performed on adsorption of H2O mols. on Ti-doped silicon clusters TiSin using the ultrasoft pseudopotential method within the generalized gradient approxn. For n = 13 and larger clusters adsorption of H2O on TiSin could be difficult due to low binding energies. All these clusters have cage structures with the metal atom surrounded by the silicon atoms. On the other hand, smaller clusters with n <13 have the metal atom partially covered by Si atoms in a basket structure so that it is available for reaction with a water mol. This leads to significantly higher binding energies of a water mol. on such clusters. These results are in excellent agreement with the available exptl. data, which show significant decrease of H2O adsorption on clusters with n >12.
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514Shibuta, M.; Kamoshida, T.; Ohta, T.; Tsunoyama, H.; Nakajima, A. Oxidative reactivity of alkali-like superatoms of group 5 metal-encapsulating Si16 cage nanoclusters. Comm. Chem. 2018, 1, 50, DOI: 10.1038/s42004-018-0052-9Google ScholarThere is no corresponding record for this reference.
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515Shibuta, M.; Niikura, T.; Kamoshida, T.; Tsunoyama, H.; Nakajima, A. Nitric oxide oxidation of a Ta encapsulating Si cage nanocluster superatom (Ta@Si16) deposited on an organic substrate; a Si cage collapse indicator. Phys. Chem. Chem. Phys. 2018, 20, 26273– 26279, DOI: 10.1039/C8CP05580GGoogle Scholar515https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVamt7%252FE&md5=7b972c030f6c09326928f80d3eb38751Nitric oxide oxidation of a Ta encapsulating Si cage nanocluster superatom (Ta@Si16) deposited on an organic substrate; a Si cage collapse indicatorShibuta, Masahiro; Niikura, Toshiki; Kamoshida, Toshiaki; Tsunoyama, Hironori; Nakajima, AtsushiPhysical Chemistry Chemical Physics (2018), 20 (41), 26273-26279CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The chem. reaction kinetics of an alkali-like superatom comprising a tantalum encapsulating Si16 cage nanocluster (Ta@Si16) deposited on an n-type org. substrate composed of overlayered C60 fullerene upon exposure to nitric oxide (NO) as a reactive gas are investigated. Core level XPS reveals that Ta@Si16 oxidn. with NO proceeds stepwise from the outer Si16 cage to the central Ta atom; during the initial stage, NO is dissociatively chemisorbed by the cage surface of Ta@Si16 without penetrating the cage, while under extreme reaction conditions, the collapse of the Si16 cage leads to NO oxidn. of the central Ta atom. In particular, mol. NO adsorption is assocd. with Ta oxidn. only after the collapse of the Si16 cage of Ta@Si16. The reaction kinetics of M@Si16 with NO in the earlier stages of oxidn. are discussed in conjunction with d. functional theory calcns. Due to the superat. nature of the shell closure with valence electrons coupled with metal encapsulation, surface oxidn. of the caged Si in Ta@Si16 takes place gently compared to that of a naked Si surface, with molecularly physisorbed NO functioning as an indicator of Si cage collapse.
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516Belomoin, G.; Therrien, J.; Smith, A.; Rao, S.; Twesten, R.; Chaieb, S.; Nayfeh, M. H.; Wagner, L.; Mitas, L. Observation of a magic discrete family of ultrabright Si nanoparticles. Appl. Phys. Lett. 2002, 80, 841– 843, DOI: 10.1063/1.1435802Google Scholar516https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xpt1emsw%253D%253D&md5=6b6373a0bfd5687b50e7fe4648674fceObservation of a magic discrete family of ultrabright Si nanoparticlesBelomoin, G.; Therrien, J.; Smith, A.; Rao, S.; Twesten, R.; Chaieb, S.; Nayfeh, M. H.; Wagner, L.; Mitas, L.Applied Physics Letters (2002), 80 (5), 841-843CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Electrochem. etched, H capped SinHx clusters with n > 20 are obtained within a family of discrete sizes. These sizes are 1.0 (Si29), 1.67 (Si123), 2.15, 2.9, and 3.7 nm in diam. The particles were characterize via direct electron imaging, excitation and emission optical spectroscopy, and colloidal crystn. The band gaps and emission bands are measured. The smallest 4 are ultrabright blue, green, yellow and red luminescent particles. The availability of discrete sizes and distinct emission in the red, green and blue (RGB) range is useful for biomedical tagging, RGB displays, and flash memories.
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517Li, S.; Xue, X.; Zhai, H.; Nie, X.; Wang, F.; Sun, Q.; Jia, Y.; Guo, Z.; Shevlin, S. High inertness of W@Si12 cluster toward O2 molecule. Phys. Lett. A 2012, 376, 1454– 1459, DOI: 10.1016/j.physleta.2012.03.005Google Scholar517https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjvVajsr0%253D&md5=a338ff01fe2818456058f94cb7116cb8High inertness of W@Si12 cluster toward O2 moleculeLi, S. F.; Xue, Xinlian; Zhai, Hao; Nie, Xinchuang; Wang, Fei; Sun, Q.; Jia, Yu; Guo, Z. X.; Shevlin, S. A.Physics Letters A (2012), 376 (17), 1454-1459CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The geometry, electronic structure, and reactivity with O2 mols. of an isolated W@Si12 cluster have been investigated by first principles simulations. The results confirm that O2 can weakly adsorb on the HP-W@Si12 cage with a binding energy of 0.004 to 0.027 eV. O2 may dissoc. on the cluster by overcoming energy barrier of at least 0.593 eV. However, this is a spin-forbidden reaction, rendering the high inertness of the HP-W@Si12 cluster toward O2. These results confirm the high inertness of the W@Si12 cluster toward O2 mols. in ambient conditions, in close agreement with exptl. observations of magic cluster of W@Si12.
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518Yong, Y.; Lv, S.; Li, X.; Li, T.; Cui, H. W@Si12 cluster as a potential sensor for CO and NO detection. EPL 2015, 111, 10006, DOI: 10.1209/0295-5075/111/10006Google ScholarThere is no corresponding record for this reference.
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519Zhou, S.; Yang, X.; Pei, W.; Zhao, J.; Du, A. Silicon nanocages for selective carbon dioxide conversion under visible light. J. Phys. Chem. C 2019, 123, 9973– 9980, DOI: 10.1021/acs.jpcc.9b01784Google Scholar519https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXmtlKntro%253D&md5=d90e926f8fab6b423d9d51ec665d7a37Silicon Nanocages for Selective Carbon Dioxide Conversion under Visible LightZhou, Si; Yang, Xiaowei; Pei, Wei; Zhao, Jijun; Du, AijunJournal of Physical Chemistry C (2019), 123 (15), 9973-9980CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Artificial photosynthesis for CO2 conversion to fuels and value-added chems. is a tactic to close the anthropogenic carbon cycle. To this end, developing efficient catalysts composed of earth-abundant, economic, and eco-friendly elements is desirable but challenging. By comprehensive ab initio calcns., wit is shown for the first time that caged silicon clusters doped by vanadium atom (VSin, n = 12-15) can catalyze CO2 hydrogenation to various C1 products (i.e., carbon monoxide, formic acid, formaldehyde, methanol, and methane) with kinetic barriers down to 0.67-1.53 eV and selectivity uniquely detd. by cluster size and geometry. These clusters, which can be produced in lab. with good stability, have suitable energy gap and can absorb sunlight from the visible to UV regime for driving the catalysis. Hence, these metal-doped Si clusters form a potential family of photocatalysts for selective CO2 hydrogenation. Their superior catalytic activity stems from the unsatd. states of the Si cage, which are mediated by sp-d hybridization and V-Si charge transfer. The CO2 adsorption strength is correlated with the coordination no. and p orbital center of Si atoms. Such geometry-electronic structure-activity correlation should be applicable to the atomically precise design of novel silicon-based nanocatalysts for various renewable energy applications.
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520Zhou, S.; Yang, X.; Pei, W.; Liu, N.; Zhao, J. Heterostructures of MXenes and N-doped graphene as highly active bifunctional electrocatalysts. Nanoscale 2018, 10, 10876– 10883, DOI: 10.1039/C8NR01090KGoogle Scholar520https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXksVelur0%253D&md5=2e7596e6f26ada6a3901ca94da0a755dHeterostructures of MXenes and N-doped graphene as highly active bifunctional electrocatalystsZhou, Si; Yang, Xiaowei; Pei, Wei; Liu, Nanshu; Zhao, JijunNanoscale (2018), 10 (23), 10876-10883CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)MXenes with versatile chem. and superior elec. cond. are prevalent candidate materials for energy storage and catalysts. Inspired by recent expts. of hybridizing MXenes with carbon materials, here we theor. design a series of heterostructures of N-doped graphene supported by MXene monolayers as bifunctional electrocatalysts for the oxygen redn. reaction (ORR) and hydrogen evolution reaction (HER). Our first-principles calcns. show that the graphitic sheet on V2C and Mo2C MXenes are highly active with an ORR overpotential down to 0.36 V and reaction free energies for the HER approaching zero, both with low kinetic barriers. Such outstanding catalytic activities originate from the electronic coupling between the graphitic sheet and the MXene, and can be correlated with the pz band center of surface carbon atoms and the work function of the heterostructures. Our findings screen a novel form of highly active electrocatalysts by taking advantage of the fast charge transfer kinetics and strong interfacial coupling of MXenes, and illuminate a universal mechanism for modulating the catalytic properties of two-dimensional hybrid materials.
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521Pei, W.; Zhou, S.; Bai, Y.; Zhao, J. N-doped graphitic carbon materials hybridized with transition metals (compounds) for hydrogen evolution reaction: Understanding the synergistic effect from atomistic level. Carbon 2018, 133, 260– 266, DOI: 10.1016/j.carbon.2018.03.043Google Scholar521https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXltlSnsbc%253D&md5=a6336494c5b80b1a300506ba7b0b0838N-doped graphitic carbon materials hybridized with transition metals (compounds) for hydrogen evolution reaction: Understanding the synergistic effect from atomistic levelPei, Wei; Zhou, Si; Bai, Yizhen; Zhao, JijunCarbon (2018), 133 (), 260-266CODEN: CRBNAH; ISSN:0008-6223. (Elsevier Ltd.)The hybrid nanostructures of nitrogen doped carbon materials and nonprecious transition metals are among the most promising electrocatalysts to replace noble metal catalysts for renewable energy applications. However, the fundamental principles governing the catalytic activity of such hybrid materials remain elusive. Herein, we systematically explore the electrocatalytic properties of transition metals, transition metal oxides and carbides substrates covered by nitrogen-doped graphitic sheets for hydrogen evolution reaction (HER). Our first-principles calcns. show that the graphitic sheet is prominently activated by the nitrogen doping and the coordinate bond with metal (compd.) substrate through intralayer and interlayer charge transfer. Such hybrid materials can provide optimal binding capability for HER catalysis with Tafel barrier down to 1.0 eV. The HER activity can be correlated to the C pz band center, which is in turn governed by the electronic coupling strength between the graphitic sheet and metal substrate, thus paving a way to rational design of graphitic carbon/transition metal hybrid electrocatalysts of high performance.
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522Hunter, J.; Fye, J.; Jarrold, M.; Bower, J. Structural transitions in size-selected germanium cluster ions. Phys. Rev. Lett. 1994, 73, 2063– 2066, DOI: 10.1103/PhysRevLett.73.2063Google Scholar522https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXmvFWiu7g%253D&md5=e91a3e242152c8fa7995d501cf0c3df2Structural transitions in size-selected germanium cluster ionsHunter, J. M.; Fye, J. L.; Jarrold, M. F.Physical Review Letters (1994), 73 (15), 2063-6CODEN: PRLTAO; ISSN:0031-9007.Injected ion drift tube techniques were used to probe the geometries of germanium cluster ions. Clusters with ∼(10-40) atoms appear to follow a 1-dimensional growth sequence to give prolate geometries. At ∼40 atoms the clusters stop following this growth sequence, and clusters with ∼(40-70) atoms appear to retain roughly the same aspect ratio. At ∼70 atoms the clusters abruptly reconstruct to a more spherical geometry. Dissocn. energies, measured for the germanium clusters, suggest that clusters with n < 70 can be thought of as loosely bound assemblies of small strongly bound fragments (such as Ge7 and Ge10). Apparently the structural transition at ∼70 atoms may reflect a change to a more bulklike bonding arrangement.
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523Burton, G. R.; Xu, C.; Arnold, C. C.; Neumark, D. M. Photoelectron spectroscopy and zero electron kinetic energy spectroscopy of germanium cluster anions. J. Chem. Phys. 1996, 104, 2757– 2764, DOI: 10.1063/1.471098Google Scholar523https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xht1Kru7g%253D&md5=50cc3a390d235a1f51588f5160c8ee1cPhotoelectron spectroscopy and zero electron kinetic energy spectroscopy of germanium cluster anionsBurton, Gordon R.; Xu, Cangshan; Arnold, Caroline C.; Neumark, Daniel M.Journal of Chemical Physics (1996), 104 (8), 2757-64CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Anion photoelectron spectra of Gen-, n = 2-15, have been measured using an incident photon energy of 4.66 eV. In addn., the spectra of Ge2-, Ge3-, and Ge4- have been measured at photon energies of 3.49 and 2.98 eV. From these spectra the electron affinity of the corresponding neutral cluster has been detd. Vibrational frequencies and term values for several electronic states of Ge2- and Ge3- have been detd. Vibrational structure in the 3B3u excited state of Ge4 has been resolved using zero electron kinetic energy (ZEKE) photoelectron spectroscopy. The assignment of the spectra of Ge3- and Ge4- is facilitated by a comparison to the similar spectra of Si3- and Si4-, resp. The spectra of the larger clusters, Gen-, n = 5-15, are characterized by many broad structureless features which indicate the presence of multiple electronic transitions. Several of these were assigned based on comparison with previous ab initio calcns. on germanium and silicon clusters.
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524Gingerich, K. A.; Schmude, R., Jr; Sai Baba, M.; Meloni, G. Atomization enthalpies and enthalpies of formation of the germanium clusters, Ge5, Ge6, Ge7, and Ge8 by Knudsen effusion mass spectrometry. J. Chem. Phys. 2000, 112, 7443– 7448, DOI: 10.1063/1.481343Google Scholar524https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXis1ans7Y%253D&md5=8f63475962c2ed46008e7677ce6a6f8cAtomization enthalpies and enthalpies of formation of the germanium clusters, Ge5, Ge6, Ge7, and Ge8 by Knudsen effusion mass spectrometryGingerich, K. A.; Schmude, R. W., Jr.; Sai Baba, M.; Meloni, G.Journal of Chemical Physics (2000), 112 (17), 7443-7448CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The high-temp. mass spectrometric method was employed to measure the equil. partial pressures of small germanium clusters above liq. germanium contained in a graphite Knudsen cell. These data were combined with new thermal functions, calcd. from recent theor. and spectroscopic mol. parameters, to evaluate the atomization enthalpies and enthalpies of formation of Ge5-Ge8. Mass spectrometric equil. data available in literature were also reevaluated. The following atomization enthalpies, ΔaH0o(Gen,g) and enthalpies of formation ΔfH298.15o(Gen,g), in kJ mol-1, have been obtained: Ge5, 1313±27 and 548±27, Ge6, 1649±33 and 583±33, Ge7, 2008±42 and 598±42, Ge8, 2359±60 and 618±60. The atomization energies are compared with available theor. values.
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525Schäfer, S.; Schäfer, R. Dielectric response of germanium clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 205211, DOI: 10.1103/PhysRevB.77.205211Google ScholarThere is no corresponding record for this reference.
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526Wang, J.; Wang, G.; Zhao, J. Structure and electronic properties of Gen (n = 2–25) clusters from density-functional theory. Phys. Rev. B: Condens. Matter Mater. Phys. 2001, 64, 205411, DOI: 10.1103/PhysRevB.64.205411Google Scholar526https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXot1WiurY%253D&md5=4ee3951ff5bfe40aaeb405eaa7b1ca62Structure and electronic properties of Gen (n = 2-25) clusters from density-functional theoryWang, Jinlan; Wang, Guanghou; Zhao, JijunPhysical Review B: Condensed Matter and Materials Physics (2001), 64 (20), 205411/1-205411/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The geometrical and electronic structures of the germanium clusters with up to 25 atoms are studied by using d.-functional theory with the generalized gradient approxn. The Gen clusters follow a prolate growth pattern with n ≥ 13. For medium-sized clusters, we find two kinds of competing structures, stacked layered structures and compact structures. The stacked layered structures with capped tetrahedron Ge9 cluster are more stable than compact structures and other stacked structures. The size dependence of cluster binding energies, highest-occupied and lowest-unoccupied MO gap, and ionization potentials are discussed and compared with expts.
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527Bulusu, S.; Yoo, S.; Zeng, X. C. Search for global minimum geometries for medium sized germanium clusters: Ge12–Ge20. J. Chem. Phys. 2005, 122, 164305, DOI: 10.1063/1.1883647Google Scholar527https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXksFKhs70%253D&md5=bd5a0cc301aeab156bdeed28a62fee8aSearch for global minimum geometries for medium sized germanium clusters: Ge12-Ge20Bulusu, S.; Yoo, S.; Zeng, X. C.Journal of Chemical Physics (2005), 122 (16), 164305/1-164305/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We performed an unbiased search for the global min. geometries of small-to-medium sized germanium clusters Gen(12≤n≤18) as well as a biased search (using seeding method) for Gen(17≤n≤20). We employed the basin-hopping algorithm coupled with the plane-wave pseudopotential d. functional calcns. For each size, we started the unbiased search with using several structurally very different initial clusters, or we started the biased search with three different seeds. Irresp. of the initial structures of clusters we found that the obtained lowest-energy clusters of the size n = 12-16 and 18 are the same. Among them, the predicted global min. of Gen(12≤n≤16) are identical to those reported previously [Shvartsburg et al., Phys. Rev. Lett. 83, 167 (1999)]. For n = 17-20, we identified two or three nearly isoenergetic low-lying isomers (for each size) that compete for the global min. Nearly all the low-lying clusters in the size range of 12≤n≤20 contain the tri-capped trigonal prism motif and are all prolate in geometry, in agreement with the expt.
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528Kumar, V.; Kawazoe, Y. Metal-encapsulated icosahedral superatoms of germanium and tin with large gaps: Zn@Ge12 and Cd@Sn12. Appl. Phys. Lett. 2002, 80, 859– 861, DOI: 10.1063/1.1447315Google Scholar528https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xpt1emtQ%253D%253D&md5=b0bdb60c8de1a3644bfdab52feac1752Metal-encapsulated icosahedral superatoms of germanium and tin with large gaps: Zn@Ge12 and Cd@Sn12Kumar, Vijay; Kawazoe, YoshiyukiApplied Physics Letters (2002), 80 (5), 859-861CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Metal (M)-encapsulated clusters of Ge and Sn, Zn@Ge12 and Cd@Sn12, are obtained from total energy calcns. using ab initio pseudopotential plane wave method and generalized gradient approxn. for the exchange-correlation energy. These have perfect icosahedral symmetry and large highest occupied-LUMO gap of ∼2 eV. It lies in the optical region and makes these species attractive for cluster assembled optoelectronic materials. Calcns. on Si clusters doped with Be show a different behavior.
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529Singh, A. K.; Kumar, V.; Kawazoe, Y. Thorium encapsulated caged clusters of germanium: Th@Gen, n = 16, 18, and 20. J. Phys. Chem. B 2005, 109, 15187– 15189, DOI: 10.1021/jp053169dGoogle Scholar529https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmsFWntb0%253D&md5=b006d0b5a9eb1b59eb0f25512d9e54deThorium Encapsulated Caged Clusters of Germanium: Th@Gen, n = 16, 18, and 20Singh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiJournal of Physical Chemistry B (2005), 109 (32), 15187-15189CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)We report from ab initio calcns. that thorium encapsulation can be used to stabilize highly sym. cages of germanium with 16 and 20 atoms. The lowest energy structures of these clusters are different from the recently found silicon fullerenes and are similar to clusters found in bulk metallic alloys. The binding energies of these clusters are higher compared with the values for the elemental germanium clusters of comparable sizes, and this suggests a strong possibility of their exptl. realization in large quantities. Also, Th@Ge16 has a large highest occupied-LUMO (HOMO-LUMO) gap of 1.72 eV that makes it interesting for optoelectronic applications.
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530Zhang, X.; Li, G.; Gao, Z. Laser ablation of Co/Ge mixtures: A new type of endohedral structure, a semiconductor cage trapping a metal atom. Rapid Commun. Mass Spectrom. 2001, 15, 1573– 1576, DOI: 10.1002/rcm.408Google Scholar530https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXntFWntrs%253D&md5=eacf7acdc0e12d0aad4220f1be136a93Laser ablation of Co/Ge mixtures: a new type of endohedral structure, a semiconductor cage trapping a metal atomZhang, Xia; Li, Guoliang; Gao, ZhenRapid Communications in Mass Spectrometry (2001), 15 (17), 1573-1576CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)In expts. on Co/Ge binary clusters by laser vaporization, a remarkably strong signal in the mass spectrum was presented, which was assigned to the cluster anion consisting of ten Ge atoms and one Co atom, [CoGe10]-. For this cluster anion the authors suggest an endohedral structure - a Ge10 cage trapping a Co atom in its interior. Reactions between Co clusters and Ge clusters using a laser double ablation reactor also confirmed the endohedral structure. According to the electronic and geometrical shell closures, a bicapped tetragonal antiprism structure was predicted for this endohedral [CoGe10]- cluster anion.
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531Atobe, J.; Koyasu, K.; Furuse, S.; Nakajima, A. Anion photoelectron spectroscopy of germanium and tin clusters containing a transition-or lanthanide-metal atom; MGen– (n = 8–20) and MSnn– (n = 15–17)(M = Sc–V, Y–Nb, and Lu–Ta). Phys. Chem. Chem. Phys. 2012, 14, 9403– 9410, DOI: 10.1039/c2cp23247bGoogle Scholar531https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XosVWltrY%253D&md5=64d4a88016061ed3bb73c5903c87594dAnion photoelectron spectroscopy of germanium and tin clusters containing a transition- or lanthanide-metal atom; MGen- (n = 8-20) and MSnn- (n = 15-17) (M = Sc-V, Y-Nb, and Lu-Ta)Atobe, Junko; Koyasu, Kiichirou; Furuse, Shunsuke; Nakajima, AtsushiPhysical Chemistry Chemical Physics (2012), 14 (26), 9403-9410CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The electronic properties of Ge and Sn clusters contg. a transition- or lanthanide-metal atom from Group 3, 4, or 5, MGen (M = Sc, Ti, V, Y, Zr, Nb, Lu, Hf, and Ta) and MSnn (M = Sc, Ti, Y. Zr, and Hf), were studied by anion photoelectron spectroscopy at 213 nm. In the case of the group 3 elements Sc, Y, and Lu, the threshold energy of electron detachment of MGen- exhibits local max. at n = 10 and 16, while in the case of the group 4 elements Ti, Zr, and Hf, it exhibits a local min. only at n = 16, assocd. with the presence of a small bump in the spectrum. A similar behavior is obsd. for MSnn- around n = 16, and these electronic characteristics of MGen and MSnn are closely related to those of MSin. Compared to MSin, however, the larger cavity size of a Gen cage allows metal atom encapsulation at a smaller size n. A cooperative effect between the electronic and geometric structures of clusters with a large cavity of Ge16 or Sn16 is discussed together with the results of expts. that probe their geometric stability via their reactivity to H2O adsorption.
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532Deng, X. J.; Kong, X. Y.; Xu, X. L.; Xu, H. G.; Zheng, W. J. Structural and magnetic properties of CoGen– (n = 2–11) clusters: Photoelectron spectroscopy and density functional calculations. ChemPhysChem 2014, 15, 3987– 3993, DOI: 10.1002/cphc.201402615Google Scholar532https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVCrsbfI&md5=f20c13349b9f3b6810f9b9870d00180dStructural and Magnetic Properties of CoGen- (n=2-11) Clusters: Photoelectron Spectroscopy and Density Functional CalculationsDeng, Xiao-Jiao; Kong, Xiang-Yu; Xu, Xi-Ling; Xu, Hong-Guang; Zheng, Wei-JunChemPhysChem (2014), 15 (18), 3987-3993CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)A series of cobalt-doped germanium clusters, CoGen-/0 (n = 2-11), are investigated by using anion photoelectron spectroscopy combined with d. functional theory calcns. For both anionic and neutral CoGen (n = 2-11) clusters, the crit. size of the transition from exo- to endohedral structures is n = 9. Natural population anal. shows that there is electron transfer from the Gen framework to the Co atom at n = 7-11 for both anionic and neutral CoGen clusters. The magnetic moments of the anionic and neutral CoGen clusters decrease to the lowest values at n = 10 and 11. The transfer of electrons from the Gen framework to the Co atom and the minimization of the magnetic moments are related to the evolution of CoGen structures from exo- to endohedral.
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533Deng, X.-J.; Kong, X.-Y.; Xu, H.-G.; Xu, X.-L.; Feng, G.; Zheng, W.-J. Photoelectron spectroscopy and density functional calculations of VGen– (n = 3–12) clusters. J. Phys. Chem. C 2015, 119, 11048– 11055, DOI: 10.1021/jp511694cGoogle Scholar533https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFyhtLfL&md5=1e5c4f9d4d78c8b19233d6fb0f7d4403Photoelectron Spectroscopy and Density Functional Calculations of VGen- (n = 3-12) ClustersDeng, Xiao-Jiao; Kong, Xiang-Yu; Xu, Hong-Guang; Xu, Xi-Ling; Feng, Gang; Zheng, Wei-JunJournal of Physical Chemistry C (2015), 119 (20), 11048-11055CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structural, electronic and magnetic properties of VGen-/0(n = 3-12) clusters were investigated using anion photoelectron spectroscopy in combination with d. functional theory calcns. We found that the dominant geometries are exohedral for the VGen-/0 clusters with n ≤ 7. The VGe8-/0 clusters have half-encapsulated boat-shaped structures, and the opening of the boat-shaped structure is gradually covered by the addnl. Ge atoms to form Gen cage from n = 9-11. At n = 12, a D3d distorted hexagonal prism cage structure is formed. According to the natural population anal., for both anionic and neutral VGen clusters of n = 8-12, there is electron transfer from the Gen framework to the V atom and the total magnetic moments decrease to the min. The electron transfer pattern and the minimization of the magnetic moments for these clusters are related to their structural evolution.
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534Jin, Y.; Lu, S.; Hermann, A.; Kuang, X.; Zhang, C.; Lu, C.; Xu, H.; Zheng, W. Probing the structural evolution of ruthenium doped germanium clusters: Photoelectron spectroscopy and density functional theory calculations. Sci. Rep. 2016, 6, 30116, DOI: 10.1038/srep30116Google Scholar534https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXksFehs7o%253D&md5=d057a051edd65d6cbbf4ccff011df6e2Probing the structural evolution of ruthenium doped germanium clusters: Photoelectron spectroscopy and density functional theory calculationsJin, Yuanyuan; Lu, Shengjie; Hermann, Andreas; Kuang, Xiaoyu; Zhang, Chuanzhao; Lu, Cheng; Xu, Hongguang; Zheng, WeijunScientific Reports (2016), 6 (), 30116CODEN: SRCEC3; ISSN:2045-2322. (Nature Publishing Group)A review. We present a combined exptl. and theor. study of ruthenium doped germanium clusters, RuGen- (n = 3-12), and their corresponding neutral species. Photoelectron spectra of RuGen- clusters are measured at 266 nm. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) are obtained. Unbiased CALYPSO structure searches confirm the low-lying structures of anionic and neutral ruthenium doped germanium clusters in the size range of 3 ≤ n ≤ 12. Subsequent geometry optimizations using d. functional theory (DFT) at PW91/LANL2DZ level are carried out to det. the relative stability and electronic properties of ruthenium doped germanium clusters. It is found that most of the anionic and neutral clusters have very similar global features. Although the global min. structures of the anionic and neutral clusters are different, their resp. geometries are obsd. as the low-lying isomers in either case. In addn., for n > 8, the Ru atom in RuGen-/0 clusters is absorbed endohedrally in the Ge cage. The theor. predicted vertical and adiabatic detachment energies are in good agreement with the exptl. measurements. The excellent agreement between DFT calcns. and expt. enables a comprehensive evaluation of the geometrical and electronic structures of ruthenium doped germanium clusters.
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535Lu, S.-J.; Hu, L.-R.; Xu, X.-L.; Xu, H.-G.; Chen, H.; Zheng, W.-J. Transition from exohedral to endohedral structures of AuGen– (n = 2–12) clusters: Photoelectron spectroscopy and ab initio calculations. Phys. Chem. Chem. Phys. 2016, 18, 20321– 20329, DOI: 10.1039/C6CP00373GGoogle Scholar535https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XkvVSis7g%253D&md5=679da50e3cfa60b16278110b0a0fa20aTransition from exohedral to endohedral structures of AuGen- (n = 2-12) clusters: photoelectron spectroscopy and ab initio calculationsLu, Sheng-Jie; Hu, Lian-Rui; Xu, Xi-Ling; Xu, Hong-Guang; Chen, Hui; Zheng, Wei-JunPhysical Chemistry Chemical Physics (2016), 18 (30), 20321-20329CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Gold-doped germanium clusters, AuGen- (n = 2-12), were investigated by using anion photoelectron spectroscopy in combination with ab initio calcns. Their geometric structures were detd. by comparison of the theor. calcns. with the exptl. results. The results show that the most stable isomers of AuGen- with n = 2-10 are all exohedral structures with the Au atom capping the vertex, edge or face of Gen clusters, while AuGe11- is found to be the crit. size of the endohedral structure. Interestingly, AuGe12- has an Ih sym. icosahedral structure with the Au atom located at the center. The MO anal. of the AuGe12- cluster suggests that the interactions between the 5d orbitals of the Au atom and the 4s4p hybridized orbitals of the Ge atoms may stabilize the Ih sym. icosahedral cage and promote the Au atom to be encapsulated in the cage of Ge12. The NICS(0) and NICS(1) values are calcd. to be -143.7 ppm and -36.3 ppm, resp., indicating that the icosahedral AuGe12- cluster is significantly arom.
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536Deng, X.-j.; Kong, X.-y.; Xu, X.-l.; Xu, H.-g.; Zheng, W.-j. Photoelectron spectroscopy and density functional calculations of TiGen– (n = 7–12) clusters. Chin. J. Chem. Phys. 2016, 29, 123– 128, DOI: 10.1063/1674-0068/29/cjcp1511232Google Scholar536https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XkvVCisbs%253D&md5=dafe82a8df9fff5699f6bce3d1a63bfdPhotoelectron Spectroscopy and Density Functional Calculations of TiGen- (n=7-12) ClustersDeng, Xiao-jiao; Kong, Xiang-yu; Xu, Xi-ling; Xu, Hong-guang; Zheng, Wei-junChinese Journal of Chemical Physics (2016), 29 (1), 123-128CODEN: CJCPA6; ISSN:1674-0068. (Chinese Physical Society)The growth pattern and electronic properties of TiGen- (n=7-12) clusters were investigated using anion photoelectron spectroscopy and d. functional theory calcns. For both anionic and neutral TiGen clusters, a half-encapsulated boat-shaped structure appears at n=8, and the boat-shaped structure is gradually covered by the addnl. Ge atoms to form Gen cage at n=9-11. TiGe12- cluster has a distorted hexagonal prism cage structure. According to the natural population anal., the electron transfers from the Gen framework to the Ti atom for TiGen-/0 clusters at n=8-12, implying that the electron transfer pattern is related to the structural evolution.
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537Deng, X.-J.; Kong, X.-Y.; Liang, X.; Yang, B.; Xu, H.-G.; Xu, X.-L.; Feng, G.; Zheng, W.-J. Structural and magnetic properties of FeGen–/0 (n = 3-12) clusters: Mass-selected anion photoelectron spectroscopy and density functional theory calculations. J. Chem. Phys. 2017, 147, 234310, DOI: 10.1063/1.5000886Google Scholar537https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVejsLnL&md5=8868a9d2d23dd94d7a1988a2b1ab8fbcStructural and magnetic properties of FeGen-/0 (n = 3-12) clusters: Mass-selected anion photoelectron spectroscopy and density functional theory calculationsDeng, Xiao-Jiao; Kong, Xiang-Yu; Liang, Xiaoqing; Yang, Bin; Xu, Hong-Guang; Xu, Xi-Ling; Feng, Gang; Zheng, Wei-JunJournal of Chemical Physics (2017), 147 (23), 234310/1-234310/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structural, electronic, and magnetic properties of FeGen-/0 (n = 3-12) clusters were investigated by using anion photoelectron spectroscopy in combination with DFT-B3PW91 method. For both anionic and neutral FeGen (n = 3-12) clusters with n ≤ 7, the dominant structures are exohedral. The FeGe8-/0 clusters have half-encapsulated boat-shaped structures, and the opening of the boat-shaped structure is gradually covered by the addnl. Ge atoms to form Gen cage from n = 9 to 11. The structures of FeGe10-/0 can be viewed as two Ge atoms sym. capping the opening of the boat-shaped structure of FeGe8, and those of FeGe12-/0 are distorted hexagonal prisms with the Fe atom at the center. Natural population anal. shows that there is an electron transfer from the Ge atoms to the Fe atom at n = 8-12. The total magnetic moment of FeGen-/0 and local magnetic moment of the Fe atom have not been quenched. (c) 2017 American Institute of Physics.
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538Liang, X.-Q.; Deng, X.-J.; Lu, S.-J.; Huang, X.-M.; Zhao, J.-J.; Xu, H.-G.; Zheng, W.-J.; Zeng, X. C. Probing structural, electronic, and magnetic properties of iron-doped semiconductor clusters Fe2Gen–/0 (n = 3–12) via joint photoelectron spectroscopy and density functional study. J. Phys. Chem. C 2017, 121, 7037– 7046, DOI: 10.1021/acs.jpcc.7b00943Google Scholar538https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjs1Kmt78%253D&md5=19b8082bd592d59f0aa819b325eb8a3dProbing Structural, Electronic, and Magnetic Properties of Iron-Doped Semiconductor Clusters Fe2Gen-/0 (n = 3-12) via Joint Photoelectron Spectroscopy and Density Functional StudyLiang, Xiao-Qing; Deng, Xiao-Jiao; Lu, Sheng-Jie; Huang, Xiao-Ming; Zhao, Ji-Jun; Xu, Hong-Guang; Zheng, Wei-Jun; Zeng, Xiao ChengJournal of Physical Chemistry C (2017), 121 (12), 7037-7046CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The authors present a joint exptl. and theor. study on double Fe atom doped Ge clusters, Fe2Gen-/0 (n = 3-12). The exptl. photoelectron spectra of cluster anions are reasonably reproduced by theor. simulations. The low-lying structures of the Fe-doped semiconductor clusters are obtained by using an ab initio computation-based genetic-algorithm global optimization method. The smaller-sized Fe2Gen- (n = 3-8) clusters adopt bipyramid-based geometries, while the larger ones (n ≥ 9) adopt polyhedral cage-like structures with 1 interior Fe atom. Starting from n = 8, the most stable anionic clusters Fe2Gen- exhibit structures that are different from that of their neutral counterparts Fe2Gen. Robust ferromagnetic interaction is found between the 2 doped Fe atoms in the neutral clusters Fe2Gen, while the total spin moment always remains at 4 μB for all the neutral double Fe atom doped Ge clusters up to n = 12. This behavior is in Stark contrast to the magnetic quenching behavior typically obsd. in Ge clusters doped with a single Fe atom.
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539Liang, X.; Kong, X.; Lu, S.-J.; Huang, Y.; Zhao, J.; Xu, H.-G.; Zheng, W.; Zeng, X. C. Structural evolution and magnetic properties of anionic clusters Cr2Gen (n = 3–14): Photoelectron spectroscopy and density functional theory computation. J. Phys.: Condens. Matter 2018, 30, 335501, DOI: 10.1088/1361-648X/aad2bfGoogle Scholar539https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvFKrtL%252FM&md5=cadb0b1cca75198f0d0b9182819edf50Structural evolution and magnetic properties of anionic clusters Cr2Gen (n = 3 - 14): photoelectron spectroscopy and density functional theory computationLiang, Xiaoqing; Kong, Xiangyu; Lu, Sheng-Jie; Huang, Yingying; Zhao, Jijun; Xu, Hong-Guang; Zheng, Weijun; Zeng, Xiao ChengJournal of Physics: Condensed Matter (2018), 30 (33), 335501/1-335501/11CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Structural, electronic, and magnetic properties of Cr2Gen- clusters were investigated by using photoelectron spectroscopy and DFT-PBE method using genetic algorithm optimization. For Cr2Gen- with n ≤ 8, the cluster have bipyramid-based structures. Cr2Ge9- cluster has an opening in its cage-like structure; for n = 10 to 14 this structure is gradually covered by addnl. Ge atoms to form closed-cage configuration with one interior Cr atom. The two Cr atoms in Cr2Gen- clusters tend to form a Cr-Cr bond rather than to be sepd. Interestingly, the magnetic moment of all anionic clusters considered is 1 μB. Almost all clusters exhibit antiferromagnetic Cr-Cr coupling, except for two clusters, Cr2Ge5- and Cr2Ge6. To the best of our knowledge, the Cr2Gen- clusters are the first kind of transition-metal doped semiconductor clusters that exhibit relatively stable antiferromagnetism within a wide size range. The exptl./theor. results suggest high potential to modify the magnetic behavior of semiconductor clusters through introducing different transition-metal dopant atoms.
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540Goicoechea, J. M.; Sevov, S. C. [(Pd–Pd)@Ge18]4-: A palladium dimer inside the largest single-cage deltahedron. J. Am. Chem. Soc. 2005, 127, 7676– 7677, DOI: 10.1021/ja051224qGoogle Scholar540https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvVehs70%253D&md5=c8839d8168f2b6932f2a90cc54fd08e0[(Pd-Pd)@Ge18]4-: A Palladium Dimer Inside the Largest Single-Cage DeltahedronGoicoechea, Jose M.; Sevov, Slavi C.Journal of the American Chemical Society (2005), 127 (21), 7676-7677CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The largest single-cage deltahedral cluster is made of 18 germanium atoms and is centered by a pair of palladium atoms. Its shape is very close to the ideal D3d symmetry expected and predicted for a cluster of this size.
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541Zhou, B.; Denning, M. S.; Kays, D. L.; Goicoechea, J. M. Synthesis and isolation of [Fe@Ge10]3–: A pentagonal prismatic zintl ion cage encapsulating an interstitial iron atom. J. Am. Chem. Soc. 2009, 131, 2802– 2803, DOI: 10.1021/ja900055jGoogle Scholar541https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFWns7Y%253D&md5=741a5ecf963fa530134de0595ad8a049Synthesis and Isolation of [Fe@Ge10]3-: A Pentagonal Prismatic Zintl Ion Cage Encapsulating an Interstitial Iron AtomZhou, Binbin; Denning, Mark S.; Kays, Deborah L.; Goicoechea, Jose M.Journal of the American Chemical Society (2009), 131 (8), 2802-2803CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Reaction of an ethylenediamine (en) soln. of the Zintl phase precursor K4Ge9 with FeAr2 (Ar = 2,6-Mes2C6H3) in the presence of 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) yielded the endohedral Zintl ion [Fe@Ge10]3- (1) which was crystallog. characterized as a [K(2,2,2-crypt)]+ salt in [K(2,2,2-crypt)]3[Fe@Ge10]•2en. This unprecedented Zintl ion exhibits a pentagonal prismatic 10-atom Ge cage with an interstitial Fe atom in the central cavity. Confirmation of the existence of the cluster anion in soln. was corroborated by pos. and neg. ion mode electrospray mass spectrometry.
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542Wang, J. Q.; Stegmaier, S.; Fässler, T. F. [Co@Ge10]3–: An intermetalloid cluster with Archimedean pentagonal prismatic structure. Angew. Chem., Int. Ed. 2009, 48, 1998– 2002, DOI: 10.1002/anie.200805511Google Scholar542https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjsFaksrc%253D&md5=19c33326dbb02761385c9a6e4a2479cf[Co@Ge10]3-: an intermetalloid cluster with Archimedean pentagonal prismatic structureWang, Jian-Qiang; Stegmaier, Saskia; Fassler, Thomas F.Angewandte Chemie, International Edition (2009), 48 (11), 1998-2002CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The unusual structure of [Co@Ge10]3-, which was obtained by the reaction of K4Ge9 with [Co(C8H12)(C8H13)] in ethylenediamine, raises questions about chem. bonding in the anion. The Zintl ion cluster has virtual Dsh symmetry and is a unique example of a ligand-free cluster that is not a deltahedron. The optimized geometry (DFT calcns.) and delocalized chem. bonding are discussed.
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543Espinoza-Quintero, G.; Duckworth, J. C.; Myers, W. K.; McGrady, J. E.; Goicoechea, J. M. Synthesis and characterization of [Ru@Ge12]3–: An endohedral 3-connected cluster. J. Am. Chem. Soc. 2014, 136, 1210– 1213, DOI: 10.1021/ja411280vGoogle Scholar543https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXksVKh&md5=d2f1fba93f171f833265d078fb6aea8cSynthesis and Characterization of [Ru@Ge12]3-: An Endohedral 3-Connected ClusterEspinoza-Quintero, Gabriela; Duckworth, Jack C. A.; Myers, William K.; McGrady, John E.; Goicoechea, Jose M.Journal of the American Chemical Society (2014), 136 (4), 1210-1213CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The 12-vertex endohedral cluster [Ru@Ge12]3- reveals an unprecedented D2d-sym. 3-connected polyhedral geometry. The structure contrasts dramatically with the known deltahedral or approx. deltahedral geometries of [M@Pb12]2- (M = Ni, Pd, Pt) and [Mn@Pb12]3- and is a result of extensive delocalization of electron d. from the transition-metal center onto the cage.
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544Li, G.; Zhang, X.; Tang, Z.; Gao, Z. Theoretical studies on the structure of the endohedral CoGe10– cluster anion. Chem. Phys. Lett. 2002, 359, 203– 212, DOI: 10.1016/S0009-2614(02)00736-4Google Scholar544https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XksVemt7c%253D&md5=f70c5d3a0b13b201edd02731eceff537Theoretical studies on the structure of the endohedral CoGe10- cluster anionLi, Guoliang; Zhang, Xia; Tang, Zichao; Gao, ZhenChemical Physics Letters (2002), 359 (3,4), 203-212CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The structure was studied of the endohedral CoGe10- cluster anion using ab initio (HF) and d. functional theory (DFT-B3LYP) methods in conjunction with effective core potential basis sets (LanL2DZ and LanL2DZ*). For the important structures, all-electron basis sets plus polarization and diffuse functions (6-31+G*) were used. The bicapped tetragonal antiprism structure with D4d symmetry is the most stable. Compared with the fragments [Co+Ge10-(D4d)], this structure is 97.7 kcal/mol more stable at the B3LYP/LanL2DZ level. Other low-energy structures were also optimized.
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545Lu, J.; Nagase, S. Metal-doped germanium clusters MGens at the sizes of n = 12 and 10: Divergence of growth patterns from the MSin clusters. Chem. Phys. Lett. 2003, 372, 394– 398, DOI: 10.1016/S0009-2614(03)00415-9Google Scholar545https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjtFWksbg%253D&md5=d3e1e17950179dff51ae15496c03128fMetal-doped germanium clusters MGens at the sizes of n=12 and 10: divergence of growth patterns from the MSin clustersLu, Jing; Nagase, ShigeruChemical Physics Letters (2003), 372 (3,4), 394-398CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Structural and electronic properties of the metal-doped germanium clusters MGen (M = Hf, W, Os, Ni, and Zn) in the sizes of n = 12 and 10 are investigated via d. functional theory calcns. based on the hybrid exchange-correlation energy. Their growth patterns are found different from those of the MSin clusters although the pure Gen and Sin clusters have identical geometries in the two sizes. The MGe12 (M = W and Os) and ZnGe12 clusters, with an endohedral distorted hexagonal prismatic and an endohedral perfect icosahedral structure, resp., show higher chem. stability among these checked MGen clusters. This makes them attractive for cluster-assembled materials.
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546Wang, J.; Han, J.-G. A computational investigation of copper-doped germanium and germanium clusters by the density-functional theory. J. Chem. Phys. 2005, 123, 244303, DOI: 10.1063/1.2148949Google Scholar546https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xit1ersQ%253D%253D&md5=5ef77a0b7149f8a070640e27dbbd4836A computational investigation of copper-doped germanium and germanium clusters by the density-functional theoryWang, Jin; Han, Ju-GuangJournal of Chemical Physics (2005), 123 (24), 244303/1-244303/12CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometries, stabilities, and electronic properties of Gen and CuGen (n=2-13) clusters have been systematically investigated by using d.-functional approach. According to optimized CuGen geometries, growth patterns of Cu-capped Gen or Cu-substituted Gen+1 clusters for the small- or middle-sized CuGen clusters as well as growth patterns of Cu-concaved Gen or Ge-capped CuGen-1 clusters for the large-sized CuGen clusters are apparently dominant. The av. at. binding energies and fragmentation energies are calcd. and discussed; particularly, the relative stabilities of CuGe10 and Ge10 are the strongest among all different sized CuGen and Gen clusters, resp. These findings are in good agreement with the available exptl. results on CoGe10- and Ge10 clusters. Consequently, unlike some transition metal (TM)Si12, the hexagonal prism CuGe12 is only low-lying structure; however, the basketlike structure is located as the lowest-energy structure. Different from some TM-doped silicon clusters, charge always transfers from copper to germanium atoms in all different sized clusters. Furthermore, the calcd. HOMO and LUMO (HOMO-LUMO) gaps are obviously decreased when Cu is doped into the Gen clusters, together with the decrease of HOMO-LUMO gaps, as the size of clusters increases. Addnl., the contribution of the doped Cu atom to bond properties and polarizabilities of the Gen clusters is also discussed.
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547Wang, J.; Han, J.-G. A theoretical study on growth patterns of Ni-doped germanium clusters. J. Phys. Chem. B 2006, 110, 7820– 7827, DOI: 10.1021/jp0571675Google Scholar547https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XivVOktrs%253D&md5=eca48c850dce0f72fdbc311a18f5893aA Theoretical Study on Growth Patterns of Ni-Doped Germanium ClustersWang, Jin; Han, Ju-GuangJournal of Physical Chemistry B (2006), 110 (15), 7820-7827CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)Ni-doped germanium clusters have been systematically investigated by using the d. functional approach. The growth-pattern behaviors, stabilities, charge transfer, and polarities of these clusters are discussed in detail. Obviously different growth patterns appear between small-sized Ni-doped germanium clusters and middle- or larger-sized Ni-doped germanium clusters. The Ni-convex or substituted Gen frames for small-sized clusters as well as Ni-concaved or encapsulated Gen frames for middle- or large-sized clusters are dominant growth patterns. The calcd. fragmentation energies manifest that the magic nos. of stabilities are 5, 8, 10, and 13 for Ni-doped germanium clusters; the obtained relative stabilities exhibit that the Ni-encapsulated Ge10 cluster is the most stable species of all different-sized clusters, which is in good agreement with available exptl. observations of CoGe10-. Natural population anal. shows that different charge-transfer phenomena depend on the sizes of the Ni-doped Gen clusters. Addnl., the properties of frontier orbitals and the polarities of Ni-doped Gen clusters are also discussed.
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548Wang, J.; Han, J.-G. Geometries and electronic properties of the tungsten-doped germanium clusters: WGen (n = 1–17). J. Phys. Chem. A 2006, 110, 12670– 12677, DOI: 10.1021/jp0636219Google Scholar548https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtFertrbL&md5=101690b316299735e2327733b33c1e45Geometries and Electronic Properties of the Tungsten-Doped Germanium Clusters: WGen (n = 1-17)Wang, Jin; Han, Ju-GuangJournal of Physical Chemistry A (2006), 110 (46), 12670-12677CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Geometries assocd. with relative stabilities, energy gaps, and polarities of W-doped germanium clusters have been investigated systematically by using d. functional theory. The threshold size for the endohedral coordination and the crit. size of W-encapsulated Gen structures emerge as, resp., n = 8 and n = 12, while the fullerene-like W@Gen clusters appears at n = 14. The evaluated relative stabilities in term of the calcd. fragmentation energies reveal that the fullerene-like W@Ge14 and W@Ge16 structures as well as the hexagonal prism WGe12 have enhanced stabilities over their neighboring clusters. Furthermore, the calcd. polarities of the W@Gen reveal that the bicapped tetragonal antiprism WGe10 is a polar mol. while the hexagonal prism WGe12 is a nonpolar mol. Moreover, the recorded natural populations show that the charges transfer from the germanium framework to the W atom. Addnl., the WGe12 cluster with large HOMO-LUMO (HOMO-LUMO) gap, large fragmentation energy, and large binding energy is supposed to be suitable as a building block of assembly cluster material. It should be pointed out that the remarkable features of W@Gen clusters above are distinctly different from those of transition metal (TM) doped Gen (TM = Cu and Ni) clusters, indicating that the growth pattern of the TMGen depends on the kind of doped TM impurity.
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549Wang, J.; Han, J.-G. The growth behaviors of the Zn-doped different sized germanium clusters: A density functional investigation. Chem. Phys. 2007, 342, 253– 259, DOI: 10.1016/j.chemphys.2007.10.008Google Scholar549https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlOmt7vE&md5=722704f855c249794df2ab6fa36e022cThe growth behaviors of the Zn-doped different sized germanium clusters: A density functional investigationWang, Jin; Han, Ju-GuangChemical Physics (2007), 342 (1-3), 253-259CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)The growth of Zn-doped germanium clusters, ZnGen (n = 1-13) was investigated by the DFT-(U)B3LYP method. The growth patterns, relative stabilities, charge transfers, HOMO-LUMO gaps and polarities of these clusters are discussed in detail. The threshold size of the Gen clusters in order to encapsulate Zn atom is n = 10; the icosahedral ZnGe12 cluster shows the highest relative stability as compared to other clusters, which differs from the results for clusters doped by first-row transition metals. The calcd. fragmentation energies detd. the magic nos. of relative stabilities for the Zn-doped germanium clusters: n = 5, 9, and 12. Natural population analyses show charge transfer from Zn to Ge framework. The HOMO-LUMO gap of the icosahedral ZnGe12 is remarkably large (3.159 eV) in comparison with caged ZnGen clusters (n = 1-11, 13).
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550Jing, Q.; Tian, F.-y.; Wang, Y.-x. No quenching of magnetic moment for the GenCo (n = 1–13) clusters: First-principles calculations. J. Chem. Phys. 2008, 128, 124319, DOI: 10.1063/1.2898880Google Scholar550https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXktl2ntr4%253D&md5=671f75e74fcec57c5823e7d8d9d1d327No quenching of magnetic moment for the GenCo (n = 1-13) clusters: First-principles calculationsJing, Qun; Tian, Fu-yang; Wang, Yuan-xuJournal of Chemical Physics (2008), 128 (12), 124319/1-124319/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The authors predict that for the GenCo (n = 1-13) clusters the magnetic moment does not quench, which is dark contrast to the previous results with transition-metal-doped Sin clusters. It may be due to the unpaired electrons of the Co atom in the clusters. For the ground state structures of the GenCo (n ≥ 9) clusters, the Co atom completely falls into the center of the Ge outer frame, forming metal-encapsulated Gen cages. The doping of the Co atom enhances the stability of the host Gen clusters. The Ge10Co cluster with the bicapped tetragonal antiprism structure is more stable than others, which agrees very well with the results of the expt. of the Co/Ge binary clusters by the laser vaporization. (c) 2008 American Institute of Physics.
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551Wang, J.; Ma, L.; Zhao, J.; Wang, G. Structural growth sequences and electronic properties of manganese-doped germanium clusters: MnGen (2–15). J. Phys.: Condens. Matter 2008, 20, 335223, DOI: 10.1088/0953-8984/20/33/335223Google Scholar551https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtFCgsL%252FI&md5=cbe28ec40626373b03de3d79299e7f10Structural growth sequences and electronic properties of manganese-doped germanium clusters: MnGen (n = 2-15)Wang, Jianguang; Ma, Li; Zhao, Jijun; Wang, GuanghouJournal of Physics: Condensed Matter (2008), 20 (33), 335223/1-335223/8CODEN: JCOMEL; ISSN:0953-8984. (Institute of Physics Publishing)The structural growth sequences and electronic properties of MnGen (n = 2-15) clusters have been investigated using d. functional theory (DFT) within the generalized gradient approxn. (GGA). An extensive search of the lowest-energy structures was conducted by considering a no. of structural isomers for each cluster size. In the ground-state structures of MnGen clusters, the equil. site of the Mn atom gradually moves from the convex, surface to interior sites as the Ge cluster size varies from 2 to 15. The threshold size for the formation of caged MnGen and the sealed Mn-encapsulated Gen structure is n = 9 and n = 10, resp. Maximum peaks were obsd. for MnGen clusters at n = 3, 6, 10, 12 and 14 with the size dependent on the second-order energy difference, implying that these clusters are relatively more stable. The electronic structures and magnetic properties of MnGen in the ground-state structures are discussed. The doped Mn atom makes the HOMO-LUMO gap of the Gen clusters smaller, due to hybridization between the p states of the Ge atom and the d states of the Mn atom. Most of the Mn-doped Gen clusters carry a magnetic moment of about 1.0 μB, except that MnGe6 and MnGe11 have a magnetic moment of about 3.0 μB. Charge transfer between Mn and Ge was also obsd.
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552Wang, J.; Han, J.-G. Geometries, stabilities, and vibrational properties of bimetallic Mo2-doped Gen (n = 9–15) clusters: A density functional investigation. J. Phys. Chem. A 2008, 112, 3224– 3230, DOI: 10.1021/jp710238tGoogle Scholar552https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXislels7o%253D&md5=7ca3a930037247a61f6d81dc12abe628Geometries, Stabilities, and Vibrational Properties of Bimetallic Mo2-Doped Gen (n = 9-15) Clusters: A Density Functional InvestigationWang, Jin; Han, Ju-GuangJournal of Physical Chemistry A (2008), 112 (14), 3224-3230CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Geometries of Mo2Gen clusters were studied by the DFT-B3LYP method. The relative stabilities, charge-transfer, and vibrational properties of these clusters are presented and discussed. The dominant geometries these clusters for n = 9-12 show one Mo atom inside a Ge cage and another Mo atom on the surface. The stable geometry of Mo2Ge9 cluster is analogous to that obsd. in recent expt.. The calcd. fragmentation energies and the relative stabilities demonstrate that the Mo2-doped Ge12 is the most stable structure. The crit. size of Mo2-encapsulated cage-like germanium clusters is n = 15. The largest energy gap and highest stability of Mo2Ge12 enable this species to be a unit for multiple metal Mo-doped germanium nanotubes. Vibrational mode analyses of Mo2Gen clusters demonstrate that the Mo-Mo stretching vibrations are sensitive to the geometries of the germanium frame, and that the point-group symmetry of germanium clusters affects the Mo-Mo stretching vibration relative to the IR inactive vibration.
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553Zhao, W.-J.; Wang, Y.-X. Geometries, stabilities, and electronic properties of FeGen (n = 9–16) clusters: Density-functional theory investigations. Chem. Phys. 2008, 352, 291– 296, DOI: 10.1016/j.chemphys.2008.07.006Google Scholar553https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGltrjE&md5=394a265dc7b3d22499e0c85d0ebd0230Geometries, stabilities, and electronic properties of FeGen (n=9-16) clusters: Density-functional theory investigationsZhao, Wen-Jie; Wang, Yuan-XuChemical Physics (2008), 352 (1-3), 291-296CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)Fe-doped germanium clusters have been systematically investigated by using the d.-functional approach. It was found that doping of one Fe atom contributes to strengthening the stability of the germanium framework. Maximum peaks of the fragmentation energies, the second-order energy differences, and the HOMO and LUMO (HOMO-LUMO) gaps were obsd. for clusters of sizes n = 9, 11, 13, 14, and 16, implying their relative higher stability than other-sized FeGe n clusters. In addn., the strongest stability of FeGe14 might stem from its highest symmetry (Oh). The HOMO-LUMO gaps are obviously reduced when the Fe atom is doped into the Gen clusters. We also found that charge always transfers from iron to germanium atoms in all sized FeGen clusters and the magnetic moment of the Fe atom does not quench when embedded in large-sized Gen (n = 10, 11, 12, and 16) clusters.
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554Wang, J.; Chen, X.; Liu, J. H. Investigation of a size-selective single hafnium-encapsulated germanium cage. J. Phys. Chem. A 2008, 112, 8868– 8876, DOI: 10.1021/jp804433dGoogle Scholar554https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVaitL%252FP&md5=3ccd30f478825d7635f1fc6911da9dafInvestigation of a Size-Selective Single Hafnium-Encapsulated Germanium CageWang, Jin; Chen, Xing; Liu, Jin HuaiJournal of Physical Chemistry A (2008), 112 (37), 8868-8876CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The structures, relative stabilities, and electronic properties of Hf@Gen clusters (n = 9-24) were calcd. by the DFT-B3LYP method. The dominant growth behavior of Hf@Gen is based on a pentagonal prism instead of a hexagonal prism. Analogous to Hf@Sin, the encapsulated fullerene-like structure of Hf@Gen begins to appear at n = 14, which is consistent with the prediction from the reactivity toward water in a recent expt. Also, similar to Hf@Sin in the previous exptl. observation, the binding energy of Hf@Gen increases gradually up to n = 16 and tends to get lower for n > 16 suggesting that stabilization of large germanium cages needs to be realized by doping with more Hf atoms. The Hf atom will obviously move away from the center of the cage for n > 20. According to anal. of the electron d. of size-selective Hf@Gen, the covalent character in the germanium framework can be affected by the encapsulated position of Hf. In addn., comparison between typical low-lying Hf@Gen and Hf@Sin cages (n = 12, 16 and 20) indicates that large-scaled divergence exists in stabilities, growth behaviors, electronic properties, and so forth.
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555Zhao, W.-J.; Wang, Y.-X. Geometries, stabilities, and magnetic properties of MnGen (n = 2–16) clusters: Density-functional theory investigations. J. Mol. Struct.: THEOCHEM 2009, 901, 18– 23, DOI: 10.1016/j.theochem.2008.12.039Google Scholar555https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjslOlsr8%253D&md5=d9ff27398e4c0372537ff58b65dc118fGeometries, stabilities, and magnetic properties of MnGen (n =2-16) clusters: Density-functional theory investigationsZhao, Wen-Jie; Wang, Yuan-XuJournal of Molecular Structure: THEOCHEM (2009), 901 (1-3), 18-23CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)Mn-doped germanium clusters have been systematically investigated by using the d.-functional approach. It was found that doping of one Mn atom contributes to strengthening the stability of the germanium framework. Maximum peaks of the second-order energy differences were obsd. for clusters of sizes n = 5, 9, 12, and 14, implying their relative higher stability than other-sized MnGen clusters. The HOMO and LUMO (HOMO-LUMO) gaps of the MnGen clusters, with the exception of MnGe14, are generally lower than the corresponding pure germanium clusters. We also found that charge always transfers from manganese to germanium atoms in all sized MnGen clusters and the magnetic moment of the Mn atom does not quench when embedded in all sized Gen (n = 2-16) clusters.
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556King, R. B.; Silaghi-Dumitrescu, I.; Uţă, M. M. Polyhedral structures with three-, four-, and five fold symmetry in metal-centered ten-vertex germanium clusters. Chem. - Eur. J. 2008, 14, 4542– 4550, DOI: 10.1002/chem.200701582Google Scholar556https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmslGhsLg%253D&md5=9a06779755233736f330d6b905196086Polyhedral structures with three-, four-, and five fold symmetry in metal-centered ten-vertex germanium clustersKing, R. Bruce; Silaghi-Dumitrescu, Ioan; Uta, Matei-MariaChemistry - A European Journal (2008), 14 (15), 4542-4550CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Studies using d. functional theory (DFT) at the hybrid B3LYP level indicate that the relative energies of structures with three-fold, four-fold, and five-fold symmetry for centered 10-vertex bare germanium clusters of the general type M@Ge10z depend on the central metal atom M and the skeletal electron count. For M@Ge10 clusters with 20 skeletal electrons the DFT results agree with exptl. data on the isoelectronic centered 10-vertex bare metal clusters. Thus the lowest energy structure for Ni@Ge10, isoelectronic with the known Ni@In1010-, is a C3v polyhedron derived from the tetracapped trigonal prism. However, Zn@Ge102+ is isoelectronic with the known cluster Zn@In108-, which has the lowest energy structure, a D4d bicapped square antiprism. For the clusters Ni@Ge102-, Cu@Ge10-, and Zn@Ge10 that have 22 skeletal electrons the lowest energy structures are the D4d bicapped square antiprism predicted by the Wade-Mingos rules. For the clusters Ni@Ge104-, Cu@Ge103-, and Zn@Ge102- that have 24 skeletal electrons the lowest energy structures are C3v polyhedra with 10 triangular faces and 3 quadrilateral faces derived from a tetracapped trigonal prism by extreme lengthening of the edges of the capped triangular face of the underlying trigonal prism. For the clusters Cu@Ge105-, and Zn@Ge104- that have 26 skeletal electrons the lowest energy structures are the D5d pentagonal antiprisms predicted by the Wade-Mingos rules and the C3v tetracapped trigonal prism as a somewhat higher energy structure. However, for the isoelectronic Ni@Ge106- the relative energies of these two structure types are reversed so that the C3v tetracapped trigonal prism becomes the global min. The effects of electron count on the geometries of the D5d pentagonal prism and D4d bicapped square antiprism centered metal cluster structures are consistent with the bonding/antibonding characteristics of the corresponding HOMO and LUMO frontier MOs.
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557King, R.; Silaghi-Dumitrescu, I.; Uta, M. Endohedral nickel, palladium, and platinum atoms in 10-vertex germanium clusters: Competition between bicapped square antiprismatic and pentagonal prismatic structures. J. Phys. Chem. A 2009, 113, 527– 533, DOI: 10.1021/jp8066074Google Scholar557https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFChsbvO&md5=7fa495ee887cbcb7fe84131f75770b37Endohedral Nickel, Palladium, and Platinum Atoms in 10-Vertex Germanium Clusters: Competition between Bicapped Square Antiprismatic and Pentagonal Prismatic StructuresKing, R. B.; Silaghi-Dumitrescu, I.; Uta, M. M.Journal of Physical Chemistry A (2009), 113 (3), 527-533CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)D. functional theory (DFT-B3LYP) predicts significant differences in the preferred structures of endohedral M@Ge10z (M = Ni, Pd, Pt; z = 0, 2-, 4-, 6-) clusters upon a change of the central metal atom in otherwise isoelectronic systems. For the neutral clusters M@Ge10 the global min. are singlet bicapped square antiprisms. However, triplet regular pentagonal prismatic structures become increasingly energetically competitive in the series Ni → Pd → Pt. The pentagonal prismatic dianions M@Ge102- (M = Ni, Pd, Pt) appear to have closed shell structures and are the global min. for palladium and platinum. However, the global min. for Ni@Ge102- is the capped square antiprism suggested by the Wade-Mingos rules. A no. of singlet low-energy unsym. structures are found for the tetraanions M@Ge104-. However, for the palladium and platinum tetraanions triplet pentagonal prismatic structures are energetically competitive with the unsym. structures.
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558Li, X.-J.; Su, K.-H. Structure, stability and electronic property of the gold-doped germanium clusters: AuGen (n = 2–13). Theor. Chem. Acc. 2009, 124, 345, DOI: 10.1007/s00214-009-0618-9Google Scholar558https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlKrtbrO&md5=d27f80292b76ce0aeb76521030dc2323Structure, stability and electronic property of the gold-doped germanium clusters: AuGe n (n = 2-13)Li, Xiao-Jun; Su, Ke-HeTheoretical Chemistry Accounts (2009), 124 (5-6), 345-354CODEN: TCACFW; ISSN:1432-881X. (Springer)The structure, stability and electronic property of the AuGe n (n = 2-13) clusters with different spin configurations are systematically investigated with d.-functional theory approach at UB3LYP/LanL2DZ level. In examg. the lowest energy structures, it is found that the growth behaviors for the small-sized AuGe n (n = 2-9) clusters and relatively large-sized AuGe n (n = 10-13) clusters are different. As the no. of Ge atom increases, the Au atom would gradually move from convex to surface and to interior sites. For the most stable structures of AuGe n (n = 10-13) clusters, the Au atom would be completely surrounded by the Ge atoms to form Au-encapsulated Ge n cages. Natural population anal. shows that the charges always transfer from the Au atom to the Ge n framework except for the AuGe2 cluster. This indicates that the Au atom acts as electron donor even the 5d orbitals of the Au atom are not significantly involved in chem. bonding. The analyses of the av. at. binding energies as well as the dissocn. energies and the second-order differences of total energy show that the AuGe n clusters with n = 5, 9 and 12 are more stable than their neighboring ones, in which the bicapped pentagonal prism AuGe12 in D 2d symmetry is most stable. The HOMO-LUMO gaps are explored to be in the region of semiconductors and the more stable clusters have slightly smaller gaps. It could be expected that the stable clusters might be considered as the novel building blocks in practical applications, e.g., the cluster-assembled semiconductors or optoelectronic material.
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559Bandyopadhyay, D.; Sen, P. Density functional investigation of structure and stability of Gen and GenNi (n = 1–20) clusters: Validity of the electron counting rule. J. Phys. Chem. A 2010, 114, 1835– 1842, DOI: 10.1021/jp905561nGoogle Scholar559https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFKnsg%253D%253D&md5=737cb0bcecd1bab634dcaf40a15fca85Density Functional Investigation of Structure and Stability of Gen and GenNi (n = 1-20) Clusters: Validity of the Electron Counting RuleBandyopadhyay, Debashis; Sen, PrasenjitJournal of Physical Chemistry A (2010), 114 (4), 1835-1842CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Structure and electronic properties of neutral and cationic pure and Ni-doped Ge clusters contg. 1-20 Ge atoms are calcd. within the framework of LCAO d. functional theory. It is found that in clusters contg. more than 8 Ge atoms the Ni atom is absorbed endohedrally in the Ge cage. Relative stability of Ni-doped clusters at different sizes is studied by calcg. their binding energy, embedding energy of a Ni atom in a Ge cluster, highest-occupied MO to lowest-unoccupied MO gap, and the second-order energy difference. Clusters having 20 valence electrons turn out to be relatively more stable in both the neutral and the cationic series. There is, in fact, a sharp drop in IP as the valence electron count increases from 20 to 21, in agreement with predictions of shell models. Relevance of these results to the designing of Ge-based superatoms is discussed.
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560Tai, T. B.; Nguyen, M. T. Lithium atom can be doped at the center of a germanium cage: The stable icosahedral Ge12Li– cluster and derivatives. Chem. Phys. Lett. 2010, 492, 290– 296, DOI: 10.1016/j.cplett.2010.04.072Google Scholar560https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXms1ynt74%253D&md5=fe2d730b3a7213c8ca03503eada029c8Lithium atom can be doped at the center of a germanium cage: The stable icosahedral Ge12Li- cluster and derivativesTai, Truong Ba; Nguyen, Minh ThoChemical Physics Letters (2010), 492 (4-6), 290-296CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Structure and stability of the Ge12Mx clusters with M = Li, Na, Be, Mg, B, Al, and x from -1 to +1, each contg. 50 valence electrons are investigated using DFT calcns. The global min. turn to be the high symmetry icosahedral structures, with large HOMO-LUMO gaps and high detachment or ionization energies. In particular, Li is found for the first time to be located at the center of an icosahedron Ge12Li-. The high thermodn. stability of the icosahedra arises from a combination of their closed crystal field shells, spherical aromaticity and electrostatic attraction force.
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561Bandyopadhyay, D.; Kaur, P.; Sen, P. New insights into applicability of Electron-counting rules in transition metal encapsulating Ge cage clusters. J. Phys. Chem. A 2010, 114, 12986– 12991, DOI: 10.1021/jp106354dGoogle Scholar561https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVGktLjL&md5=b97c2aea2e62d8b9b05b774a83886cadNew Insights into Applicability of Electron-Counting Rules in Transition Metal Encapsulating Ge Cage ClustersBandyopadhyay, Debashis; Kaur, Prabhsharan; Sen, PrasenjitJournal of Physical Chemistry A (2010), 114 (50), 12986-12991CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The relative stability of Sc, Ti, and V encapsulating Gen clusters in the size range n = 14-20 has been studied through first-principles electronic structure calcns. based on d. functional theory. Variations of the embedding energy, gap between the highest occupied and the lowest occupied MOs, ionization potential, vertical detachment energy, and electron affinity with cluster size have been calcd. to identify clusters with enhanced stability. The enhanced stability of some clusters can be very well explained as due to the formation of a filled shell free-electron gas inside the Ge cages. For the first time, direct evidence of the formation of a free-electron gas is also presented. In some other clusters, enhanced stability is found to originate from geometric effects. Some clusters that may be expected to have enhanced stability from simple electron counting rules do not show that. These results provide new insights into the long-standing question of whether electron counting rules can explain the relative stability of transition metal encapsulated semiconductor clusters and show that these clusters are too complex for such simple generalizations.
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562Tang, C.; Liu, M.; Zhu, W.; Deng, K. Probing the geometric, optical, and magnetic properties of 3d transition-metal endohedral Ge12M (M = Sc–Ni) clusters. Comput. Theor. Chem. 2011, 969, 56– 60, DOI: 10.1016/j.comptc.2011.05.012Google Scholar562https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXps1aqtbo%253D&md5=e1cf18bb08851145c08cc27d43451f1fProbing the geometric, optical, and magnetic properties of 3d transition-metal endohedral Ge12M (M = Sc-Ni) clustersTang, Chunmei; Liu, Mingyi; Zhu, Weihua; Deng, KaimingComputational & Theoretical Chemistry (2011), 969 (1-3), 56-60CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The geometric, optical, and magnetic properties of the 3d transition-metal endohedral Ge12M (M = Sc-Ni) clusters are studied using the relativistic all-electron d. functional theory. The ground state geometry of the Ge12M cluster is probably pseudoicosahedron. The Eg shows that all Ge12M clusters are perhaps partial metallic. The optical gaps of Ge12M are blueshifted compared to that of Ge122- and can be tuned by doping different transition-metal atom. The magnetic moments of Ge12M vary from 1 to 5μ B, implying they have potential utility in new nanomaterials with tunable magnetic properties.
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563Tai, T. B.; Nguyen, M. T. Enhanced stability by three-dimensional aromaticity of endohedrally doped clusters X10M0/– with X = Ge, Sn, Pb and M = Cu, Ag. J. Phys. Chem. A 2011, 115, 9993– 9999, DOI: 10.1021/jp111324nGoogle Scholar563https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpvVerurs%253D&md5=7a504f5b89b0f7d84d0de03eebc62d00Enhanced Stability by Three-Dimensional Aromaticity of Endohedrally Doped Clusters X10M0/- with X = Ge, Sn, Pb and M = Cu, Ag, AuTai, Truong Ba; Nguyen, Minh ThoJournal of Physical Chemistry A (2011), 115 (35), 9993-9999CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The group 14 clusters encapsulated by coinage metals in neutral and anionic states X10M0/- (X = Ge, Sn, Pb and M = Cu, Ag, Au) are investigated using quantum chem. calcns. with the DFT/B3LYP functional and coupled-cluster CCSD(T) theory. Addn. of transition metals into the empty cages forms high symmetry endohedral structures, except for Ge10Ag0/-. In agreement with expts. available for X10Cu, the D4d global min. of the anions are calcd. to be magic clusters with large frontier orbital gaps, high vertical and adiabatic detachment energies, and large embedding energies and binding energies as compared to those of the empty cages X102-. The enhanced stability of these magic clusters can be rationalized by the three-dimensional aromaticity.
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564Tai, T. B.; Nguyen, H. M. T.; Nguyen, M. T. The group 14 cationic clusters by encapsulation of coinage metals X10M+, with X = Ge, Sn, Pb and M = Cu, Ag, Au: Enhanced stability of 40 valence electron systems. Chem. Phys. Lett. 2011, 502, 187– 193, DOI: 10.1016/j.cplett.2010.12.021Google Scholar564https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpsVGksw%253D%253D&md5=e9f6704b08c244ac081f4dc1da742d15The group 14 cationic clusters by encapsulation of coinage metals X10M+, with X = Ge, Sn, Pb and M = Cu, Ag, Au: Enhanced stability of 40 valence electron systemsTai, Truong Ba; Nguyen, Hue Minh Thi; Nguyen, Minh ThoChemical Physics Letters (2011), 502 (4-6), 187-193CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The coinage metal encapsulated group 14 cationic clusters X10M+ (X = Ge, Sn, Pb and M = Cu, Ag, Au) are investigated using quantum chem. calcns. While Cu- and Au-doped clusters have similar stability, Ag-doped counterparts are less stable. The D 4d global min. have large frontier orbital gaps and binding energies, and are magic clusters of 40 valence electrons that satisfy the jellium shell model. The concept of doubly spherical aromaticity, based on the no. of 2(N + 1)2 π and σ valence electrons, is proposed to account for the enhanced stability. Predictions are in good agreement with expt. for available X10Cu+ clusters.
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565King, R.; Silaghi-Dumitrescu, I.; Uta, M. Endohedral beryllium atoms in ten-vertex germanium clusters: Effect of a small interstitial atom on the cluster geometry. J. Phys. Chem. A 2011, 115, 2847– 2852, DOI: 10.1021/jp110673sGoogle Scholar565https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjt1Git7g%253D&md5=8c00a81b9a43f6005dcea5efc974568dEndohedral Beryllium Atoms in Ten-Vertex Germanium Clusters: Effect of a Small Interstitial Atom on the Cluster GeometryKing, R. B.; Silaghi-Dumitrescu, I.; Uta, M. M.Journal of Physical Chemistry A (2011), 115 (13), 2847-2852CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Ten-vertex clusters are unusually versatile because polyhedra with 3-, 4-, and 5-fold symmetry are possible and are found in exptl. known structures. Such clusters therefore provide useful probes for subtle effects on cluster structure such as changing the electron count or introducing an interstitial atom. In this connection, DFT shows that one of the smallest possible interstitial atoms, namely beryllium, has relatively little effect on the structures of Be@Ge10z (z = +2, 0, -2, -4) clusters. Thus the same C3v and D4d polyhedra are found as the lowest energy structures for the isoelectronic pairs Be@Ge102+/Ge10 and Be@Ge10/Ge102-. Even for the more complicated potential energy surfaces of the Be@Ge102-/Ge104- and Be@Ge104-/Ge106- systems, the lowest energy structures are remarkably similar. Thus the same C2v structures are the global min. for both Be@Ge102- and Ge104-. Similarly, the same slipped pentagonal prism structures are the global min. for both Be@Ge104- and Ge106-.
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566Kapila, N.; Jindal, V.; Sharma, H. Structural, electronic and magnetic properties of Mn, Co, Ni in Gen for (n = 1–13). Phys. B 2011, 406, 4612– 4619, DOI: 10.1016/j.physb.2011.09.038Google Scholar566https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlGgu7nF&md5=e26f6763a00d2a054cd962ae8c5a0116Structural, electronic and magnetic properties of Mn, Co, Ni in Gen for (n=1-13)Kapila, Neha; Jindal, V. K.; Sharma, HiteshPhysica B: Condensed Matter (Amsterdam, Netherlands) (2011), 406 (24), 4612-4619CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)The structural, electronic and magnetic properties of TMGen (TM = Mn, Co, Ni; n = 1-13) were studied using spin polarized d. functional theory. The transition metal (TM) atom prefers to occupy surface positions for n<9 and endohedral positions for n ≥ 9. The crit. size of the cluster to form endohedral complexes is at n = 9, 10 and 11 for Mn, Co and Ni, resp. The binding energy of TMGen clusters increases with increase in cluster size. The Ni doped Gen clusters showed higher stability as compared to Mn and Co doped Gen clusters. The HOMO-LUMO gap for spin up and down electronic states of Gen clusters is found to change significantly on TM doping. The magnetic moment in TMGen is introduced due to the presence of TM. The magnetic moment is mainly localized at the TM site and neighboring Ge atoms. The magnetic moment is quenched in NiGen clusters for all n except for n = 2, 4 and 8.
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567Uţă, M.; Cioloboc, D.; King, R. Cobalt-centered ten-vertex germanium clusters: The pentagonal prism as an alternative to polyhedra predicted by the Wade–Mingos rules. Inorg. Chem. 2012, 51, 3498– 3504, DOI: 10.1021/ic202226kGoogle Scholar567https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjt1SqtL0%253D&md5=56f4bdf02517d05ebaefb8b20a22adf0Cobalt-Centered Ten-Vertex Germanium Clusters: The Pentagonal Prism as an Alternative to Polyhedra Predicted by the Wade-Mingos RulesUta, M. M.; Cioloboc, D.; King, R. B.Inorganic Chemistry (2012), 51 (6), 3498-3504CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)One of the most exciting recent (2009) discoveries in metal cluster chem. is the pentagonal prismatic Co@Ge103- ion, found in [K(2,2,2-crypt)]4[Co@Ge10][Co(1,5-C8H12)2]·toluene and characterized structurally by X-ray diffraction. The complete absence of triangular faces in the pentagonal prismatic structure of Co@Ge103- contradicts expectations from the well-established Wade-Mingos rules, which predict polyhedral structures having mainly or entirely triangular faces. A theor. study on Co@Ge10z systems (z = -5 to +1) predicts a singlet D5h pentagonal prismatic global min. for the trianion Co@Ge103- in accord with this exptl. result. Redox reactions on this pentagonal prismatic Co@Ge103- trianion generate low-energy pentagonal prismatic structures for Co@Ge10z where z = 0, -1, -2, -4, and -5 having quartet, triplet, doublet, doublet, and triplet spin states, resp. Similar theor. methods predict a singlet C3v polyhedral structure for the monoanion Co@Ge10-, similar to previous theor. predictions on the isoelectronic neutral Ni@Ge10 and the structure realized exptl. in the isoelectronic Ni@In1010- found in the K10In10Ni intermetallic. Redox reactions on this C3v polyhedral Co@Ge10- monoanion generate low energy C3v polyhedral structures for Co@Ge10z where z = 0, -2, -3, and -4 having doublet, doublet, triplet, and quartet spin states, resp.
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568Uţă, M.; Cioloboc, D.; Silaghi-Dumitrescu, I.; King, R. The sphericity of the diverse 10-vertex polyhedra found in bare post-transition metal clusters: Germanium clusters with interstitial magnesium atoms as model systems. Theor. Chem. Acc. 2012, 131, 1196, DOI: 10.1007/s00214-012-1196-9Google ScholarThere is no corresponding record for this reference.
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569Uţă, M.; King, R. Endohedral beryllium atoms in germanium clusters with eight and fewer vertices: How small can a cluster be and still encapsulate a central atom?. J. Phys. Chem. A 2012, 116, 5227– 5234, DOI: 10.1021/jp302052uGoogle Scholar569https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xms1yiu74%253D&md5=91d2dba680265a3af8103329aa0a1972Endohedral Beryllium Atoms in Germanium Clusters with Eight and Fewer Vertices: How Small Can a Cluster Be and Still Encapsulate a Central Atom?Uta, M. M.; King, R. B.Journal of Physical Chemistry A (2012), 116 (21), 5227-5234CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Structures of the beryllium-centered germanium clusters Be@Genz (n = 8, 7, 6; z = -4, -2, 0, +2) have been investigated by d. functional theory to provide some insight regarding the smallest metal cluster that can encapsulate an interstitial atom. The lowest energy structures of the eight-vertex Be@Ge8z clusters (z = -4, -2, 0, +2) all have the Be atom at the center of a closed polyhedron, namely, a D4d square antiprism for Be@Ge84-, a D2d bisdisphenoid for Be@Ge82-, an ideal Oh cube for Be@Ge8, and a C2v distorted cube for Be@Ge82+. The Be-centered cubic structures predicted for Be@Ge8 and Be@Ge82+ differ from the previously predicted lowest energy structures for the isoelectronic Ge82- and Ge8. This appears to be related to the larger internal vol. of the cube relative to other closed eight-vertex polyhedra. The lowest energy structures for the smaller seven- and six-vertex clusters Be@Genz (n = 7, 6; z = -4, -2, 0, +2) no longer have the Be atom at the center of a closed Gen polyhedron. Instead, either the Gen polyhedron has opened up to provide a larger vol. for the Be atom or the Be atom has migrated to the surface of the polyhedron. However, higher energy structures are found in which the Be atom is located at the center of a Gen (n = 7, 6) polyhedron. Examples of such structures are a centered C2v capped trigonal prismatic structure for Be@Ge72-, a centered D5h pentagonal bipyramidal structure for Be@Ge7, a centered D3h trigonal prismatic structure for Be@Ge64-, and a centered octahedral structure for Be@Ge6. Cluster buildup reactions of the type Be@Genz + Ge2 → Be@Gen+2z (n = 6, 8; z = -4, -2, 0, +2) are all predicted to be highly exothermic. This suggests that interstitial clusters having an endohedral atom inside a bare post transition element polyhedron with eight or fewer vertices are less than the optimum size. This is consistent with the exptl. observation of several types of 10-vertex polyhedral bare post transition element clusters with interstitial atoms but the failure to observe such clusters with external polyhedra having eight or fewer vertices.
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570Kapila, N.; Garg, I.; Jindal, V.; Sharma, H. First principle investigation into structural growth and magnetic properties in GenCr clusters for n = 1–13. J. Magn. Magn. Mater. 2012, 324, 2885– 2893, DOI: 10.1016/j.jmmm.2012.04.042Google Scholar570https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xntlymtrc%253D&md5=84e9a975589968b36e1f8af04be0035eFirst principle investigation into structural growth and magnetic properties in GenCr clusters for n = 1-13Kapila, Neha; Garg, Isha; Jindal, V. K.; Sharma, HiteshJournal of Magnetism and Magnetic Materials (2012), 324 (18), 2885-2893CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)The ground state structures and their magnetic properties were investigated for GenCr clusters (1 ≤ n ≤ 13) using spin polarized d. functional theory. The growth behavior of GenCr clusters for ≤13 shows preference of Cr atom to stabilize at the exohedral position. The binding energy increases with the increase in cluster size, but shows a small decrease w.r.t. pure Gen clusters. Interestingly, the magnetic moment in Cr doped Gen is found to be either 4 μB or 6 μB and shows no sign of magnetic quenching in any of the ground state structures and isomers investigated up to n = 13. The magnetic moment is mainly localized at the Cr atom along with small induced magnetic moment on surrounding Ge atoms. The results are consistent with the available theor. results for ≤5.
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571Hung, Y.-M.; Ho, G.-M.; Zhang, Z.-F. Bonding properties and isomeric conversion pathways from exohedral to endohedral BeGe8 clusters. Comput. Theor. Chem. 2012, 999, 154– 161, DOI: 10.1016/j.comptc.2012.08.029Google Scholar571https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1Gqs7rM&md5=ee0106c06ae813b39a16f6b18904e073Bonding properties and isomeric conversion pathways from exohedral to endohedral BeGe8 clustersHung, Yu-Ming; Ho, Gong-Ming; Zhang, Zhen-FengComputational & Theoretical Chemistry (2012), 999 (), 154-161CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The B3LYP/6-31G* method was employed to optimize the BeGe8 isomeric structures. Some adsorptive precursors can be formed without experiencing activation energy. Hirshfeld charges and Mayer total valences anal. show that a larger extent of back-donation leading to a higher Be negativity and hypervalency. All Be-Ge bonds are covalent, not ionic, according to charge partitions and M.O. anal. Cluster energies obtained by the 6-31G* and 6-311++G(3df) basis sets show significant difference and the 6-311++G(3df) energies correlate better with bonding properties. The 6-31G* ground state is a cubic Be@Ge8 that agrees with the literature. However, the 6-311++G(3df) ground state is a cube-distorted C2v Be@Ge8 with less cage strain. The Wade-Mingos rule was added to explain this change. Conversion pathways from the lowest-energetic adsorptive exohedrons to the lowest-energetic endohedrons have been explored and the Mayer bond orders assisted to describe part of the conversion progress.
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572Kumar, M.; Bhattacharyya, N.; Bandyopadhyay, D. Architecture, electronic structure and stability of TM@Gen (TM = Ti, Zr and Hf; n = 1-20) clusters: A density functional modeling. J. Mol. Model. 2012, 18, 405– 418, DOI: 10.1007/s00894-011-1122-4Google Scholar572https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XksVamtg%253D%253D&md5=0aa0d7ae61146a3f7556e41333d2a05cArchitecture, electronic structure and stability of TM@Ge(n) (TM = Ti, Zr and Hf; n = 1-20) clusters: a density functional modelingKumar, Manish; Bhattacharyya, Nilanjana; Bandyopadhyay, DebashisJournal of Molecular Modeling (2012), 18 (1), 405-418CODEN: JMMOFK; ISSN:0948-5023. (Springer)The present study reports the geometry, electronic structure and properties of neutral and anionic transition metal (TM = Ti, Zr and Hf) doped germanium clusters contg. 1 to 20 germanium atoms within the framework of LCAO d. functional theory under spin polarized generalized gradient approxn. Different parameters, like, binding energy (BE), embedding energy (EE), energy gap between the highest occupied and lowest unoccupied MOs (HOMO-LUMO), ionization energy (IP), electron affinity (EA), chem. potential etc. of the energetically stable clusters (ground state cluster) in each size are calcd. From the variation of these parameters with the size of the clusters the most stable cluster within the range of calcn. is identified. It is found that the clusters having 20 valence electrons turn out to be relatively more stable in both the neutral and the anionic series. The sharp drop in IP as the valence electron count increases from 20 to 21 in neutral cluster is in agreement with predictions of shell models. To study the vibrational nature of the clusters, IR and Raman spectrum of some selected TM@Gen (n = 15,16,17) clusters are also calcd. and compared. In the end, relevance of calcd. results to the design of Ge-based super-atoms is discussed.
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573Bandyopadhyay, D. Architectures, electronic structures, and stabilities of Cu-doped Gen clusters: Density functional modeling. J. Mol. Model. 2012, 18, 3887– 3902, DOI: 10.1007/s00894-012-1374-7Google Scholar573https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFSltrjO&md5=8911c47fc5710822b78f5458544848f2Architectures, electronic structures, and stabilities of Cu-doped Gen clusters: density functional modelingBandyopadhyay, DebashisJournal of Molecular Modeling (2012), 18 (8), 3887-3902CODEN: JMMOFK; ISSN:0948-5023. (Springer)The present study reports the geometries, electronic structures, growth behavior, and stabilities of neutral and ionized copper-doped germanium clusters contg. 1-20 Ge atoms within the framework of LCAO d. functional theory (DFT) under the spin-polarized generalized gradient approxn. It was found that Cu-capped Gen (or Cu-substituted Gen+1) and Cu-encapsulated Ge n clusters mostly occur in the ground state at a particular cluster size (n). In order to explain the relative stabilities of the ground-state clusters, parameters such as the av. binding energy per atom (BE), the embedding energy (EE), and the fragmentation energy (FE) of the clusters were calcd., and the resulting values are discussed. To explain the chem. stabilities of the clusters, parameters such as the energy gap between the highest occupied and the lowest unoccupied MOs (the HOMO-LUMO gap), the ionization energy (IP), the electron affinity (EA), the chem. potential (μ), the chem. hardness (η), and the polarizability were calcd., and the resulting values are also discussed. Natural AO (NAO) and natural bond orbital (NBO) analyses were also used to det. the electron-counting rule that should be applied to the most stable Ge10Cu cluster. Finally, the relevance of the calcd. results to the design of Ge-based superatoms is discussed.
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574Dhaka, K.; Trivedi, R.; Bandyopadhyay, D. Electronic structure and stabilities of Ni-doped germanium nanoclusters: A density functional modeling study. J. Mol. Model. 2013, 19, 1473– 1488, DOI: 10.1007/s00894-012-1690-yGoogle Scholar574https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXksF2mtrs%253D&md5=c8d0589e0b02c8215509b777b57104e1Electronic structure and stabilities of Ni-doped germanium nanoclusters: a density functional modeling studyDhaka, Kapil; Trivedi, Ravi; Bandyopadhyay, DebashisJournal of Molecular Modeling (2013), 19 (4), 1473-1488CODEN: JMMOFK; ISSN:0948-5023. (Springer)The present study reports the geometry, electronic structure, growth behavior and stability of neutral and ionized nickel encapsulated germanium clusters contg. 1-20 germanium atoms within the framework of a linear combination of AO d. functional theory (DFT) under a spin polarized generalized gradient approxn. In the growth pattern, Ni-capped Gen and Ni-encapsulated Gen clusters appear mostly as theor. ground state at a particular size. To explain the relative stability of the ground state clusters, variation of different parameters, such as av. binding energy per atom (BE), embedding energy (EE) and fragmentation energy (FE) of the clusters, were studied together with the size of the cluster. To explain the chem. stability of the clusters, different parameters, e.g., energy gap between the highest occupied and lowest unoccupied MOs (HOMO-LUMO gap), ionization energy (IP), electron affinity (EA), chem. potential (μ), chem. hardness (η), and polarizability etc. were calcd. and are discussed. Finally, natural bond orbital (NBO) anal. was applied to understand the electron counting rule applied in the most stable Ge10Ni cluster. The importance of the calcd. results in the design of Ge-based superatoms is discussed.
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575Li, X.; Su, K.; Yang, X.; Song, L.; Yang, L. Size-selective effects in the geometry and electronic property of bimetallic Au–Ge nanoclusters. Comput. Theor. Chem. 2013, 1010, 32– 37, DOI: 10.1016/j.comptc.2013.01.012Google Scholar575https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXktlCqsbg%253D&md5=e434dbcff05eb3c11e5ba66901085f18Size-selective effects in the geometry and electronic property of bimetallic Au-Ge nanoclustersLi, Xiaojun; Su, Kehe; Yang, Xiaohui; Song, Limei; Yang, LimingComputational & Theoretical Chemistry (2013), 1010 (), 32-37CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)We systematically investigated the size-selective effects of geometrical structures and electronic properties on anionic AuGe-n (n = 1-13) nanoclusters by using d. functional theory (DFT-B3LYP) calcns. with double-ξ LanL2DZ basis set. The lowest-energy structures and their low-lying isomers were identified. Compared with the neutral clusters, the ground state structures of AuGe-8 and AuGe-9 were obviously rearranged due to the addn. of an extra electron. The threshold no. of endohedral cage-like AuGe-n clusters was favored at n = 10, whereas the most stable cluster was found at n = 12, and reflected by the av. binding energies and second-order difference in the total energies. The present results demonstrated that the induced effects by an addnl. electron to the neutral clusters can enhance their stabilities. However, the values of HOMO-LUMO gaps have a decreasing tendency along with the increasing no. of Ge atoms. Adiabatic electron affinity (AEA), vertical electron affinity (VEA), and vertical detachment energy (VDE) were obtained and discussed in detail. The chem. bondings of some stable nanoclusters were also analyzed with the electron localization function (ELF).
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576Trivedi, R.; Dhaka, K.; Bandyopadhyay, D. Study of electronic properties, stabilities and magnetic quenching of molybdenum-doped germanium clusters: A density functional investigation. RSC Adv. 2014, 4, 64825– 64834, DOI: 10.1039/C4RA11825AGoogle Scholar576https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVGktbvP&md5=68b33bead7e4a0f5328d59e052bbfff3Study of electronic properties, stabilities and magnetic quenching of molybdenum-doped germanium clusters: a density functional investigationTrivedi, Ravi; Dhaka, Kapil; Bandyopadhyay, DebashisRSC Advances (2014), 4 (110), 64825-64834CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Evolution of electronic structures, properties and stabilities of neutral and cationic molybdenum encapsulated germanium clusters (Mo@Gen, n = 1 to 20) has been investigated using the linear combination of AO d. functional theory method with effective core potential. From the variation of different thermodn. and chem. parameters of the ground state clusters during the growth process, the stability and electronic structures of the clusters is explained. From the study of the distance-dependent nucleus-independent chem. shifts (NICS), we found that Mo@Ge12 with hexagonal prism-like structure is the most stable isomer and possesses strong arom. character. D. of states (DOS) plots of different clusters is then discussed to explain the role of d-orbitals of the Mo atom in hybridization. Quenching of the magnetic moment of the Mo atom with increase in the size of the cluster is also discussed. Finally, the validity of the 18-electron counting rule is applied to further explain the stability of the metallo-inorg. magic cluster Mo@Ge12 and the possibility of Mo-based cluster-assembled materials is discussed.
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577Borshch, N.; Pereslavtseva, N.; Kurganskii, S. Spatial and electronic structures of the germanium-tantalum clusters TaGen– (n = 8–17). Phys. Solid State 2014, 56, 2336– 2342, DOI: 10.1134/S1063783414110055Google Scholar577https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVyksrrE&md5=22c56d98b94e7d410d8b471f3ac8005bSpatial and electronic structures of the germanium-tantalum clusters TaGe-n (n = 8-17)Borshch, N. A.; Pereslavtseva, N. S.; Kurganskii, S. I.Physics of the Solid State (2014), 56 (11), 2336-2342CODEN: PSOSED; ISSN:1063-7834. (SP MAIK Nauka/Interperiodica)The results of optimizing the spatial structure and calcd. electronic spectra of the TaGe-n anion clusters (n = 8-17) have been presented. The calcns. have been performed in terms of the d. functional theory. The most probable spatial structures of clusters detected in the expt. have been detd. by comparing the calcd. and available exptl. data.
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578Borshch, N.; Pereslavtseva, N.; Kurganskii, S. Spatial structure and electron energy spectra of ScGen– (n = 6–16) clusters. Russ. J. Phys. Chem. B 2015, 9, 9– 18, DOI: 10.1134/S1990793115010030Google Scholar578https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXotVSkt7k%253D&md5=41bdf6a8957db1343107a412d9209c23Spatial structure and electron energy spectra of ScGe-n (n = 6-16) clustersBorshch, N. A.; Pereslavtseva, N. S.; Kurganskii, S. I.Russian Journal of Physical Chemistry B (2015), 9 (1), 9-18CODEN: RJPCCT; ISSN:1990-7923. (SP MAIK Nauka/Interperiodica)The results of optimization of the spatial structure and the calcd. electronic spectra of anionic ScGe-n (n = 6-16) clusters are presented. Calcns. were carried out in the framework of d. functional theory. By comparing the calcn. results and available exptl. data, the three-dimensional structures of the clusters detected in the expt. are detd.
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579Dhaka, K.; Bandyopadhyay, D. Study of the electronic structure, stability and magnetic quenching of CrGen (n= 1–17) clusters: A density functional investigation. RSC Adv. 2015, 5, 83004– 83012, DOI: 10.1039/C5RA13849CGoogle Scholar579https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsFShtrzP&md5=b0ab63238d337c4e7045bc52ebef6720Study of the electronic structure, stability and magnetic quenching of CrGen (n = 1-17) clusters: a density functional investigationDhaka, Kapil; Bandyopadhyay, DebashisRSC Advances (2015), 5 (101), 83004-83012CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)In the present report the evolution of the electronic structure, stability and magnetic quenching of CrGen nanoclusters has been carried out using d. functional theory (DFT). From the nature of the variation of the different thermodn. and chem. parameters, the CrGe10 and CrGe14 ground state clusters are identified as the most stable species. It is obsd. that the enhanced stability of CrGe10 and CrGe14 are due to the closed shell filled structure of the Cr-AOs and follow the 18-electron counting rule. It is found that the strong mixing of the Cr d-orbital with the s- and p-AOs of the Ge atoms in the cluster are mainly responsible for the stability and quenching of the Cr magnetic moment in the clusters. Calcd. CPs also give addnl. information about the bonding and its effect on the stability of the clusters. Calcd. IR and Raman spectra also support these results.
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580Borshch, N.; Kurganskii, S. Spatial structure and electron energy spectrum of HfGen– (n = 6–20) clusters. Inorg. Mater. 2015, 51, 870– 876, DOI: 10.1134/S0020168515080075Google Scholar580https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVChsbbJ&md5=04b9530b922e947413005f96c37288a2Spatial structure and electron energy spectrum of HfGe-n (n = 6-20) clustersBorshch, N. A.; Kurganskii, S. I.Inorganic Materials (2015), 51 (9), 870-876CODEN: INOMAF; ISSN:0020-1685. (SP MAIK Nauka/Interperiodica)This paper presents spatial structure optimization results and calcd. electronic spectra for HfGe-n (n = 6-20) anion clusters. Comparison of the calcn. results and available exptl. data makes it possible to identify the most likely spatial structures of clusters detected in expts. Cage structures of the clusters, with an encapsulated hafnium atom, are stable for n ≥ 12. The clusters with n ≥ 12, 14, 15, and 18 are "magic" in the series of germanium-hafnium anion clusters.
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581Uţă, M.; King, R. Manganese-centered ten-vertex germanium clusters: The strong field Ge10 ligand encapsulating a transition metal. J. Coord. Chem. 2015, 68, 3485– 3497, DOI: 10.1080/00958972.2015.1073267Google Scholar581https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlGnsrnL&md5=24dc86ef3fd773ca35e30e6a7513c418Manganese-centered ten-vertex germanium clusters: the strong field Ge10 ligand encapsulating a transition metalUta, M. M.; King, R. B.Journal of Coordination Chemistry (2015), 68 (19), 3485-3497CODEN: JCCMBQ; ISSN:0095-8972. (Taylor & Francis Ltd.)The exptl. realization of pentagonal prismatic structures for M@Ge103- (M = Co, Fe) contg. interstitial transition metal atoms makes of interest the chem. of corresponding manganese derivs. Mn@Ge10z. The neutral Mn@Ge10 may be regarded as a complex of a polyhedral ligand with an interstitial Mn in the +2 oxidn. state. However, the lowest energy Mn@Ge10 structure with the expected sextet spin state for high-spin d5 Mn(II) lies ∼23 kcal mol-1 in energy above the lowest energy isomer thereby suggesting that such germanium polyhedra function as strong field ligands for encapsulated transition metals. The lowest energy structures for the Mn@Ge10z anions (z = -1 to -5) are all centered pentagonal prisms. Higher energy Mn@Ge10z structures have outer Ge10 polyhedra based on the tetracapped trigonal prism similar to the lowest energy Co@Ge10- structure and on the bicapped square antiprism similar to the B10H102- deltahedron. Other Mn@Ge10z structures have outer Ge10 polyhedra with four or five quadrilateral faces as well as six or eight triangular faces, resp. Bioctahedral (Ge5)2Mn5- structures were also found for the pentaanion with a manganese vertex common to two MnGe5 octahedra. The cationic species Mn@Ge10+ was found to have a more complicated potential surface than the anions. Tetracapped trigonal prismatic and bicapped square antiprismatic structures as well as a variety of more open structures were found for Mn@.
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582Qin, W.; Lu, W.-C.; Xia, L.-H.; Zhao, L.-Z.; Zang, Q.-J.; Wang, C.; Ho, K. Structures and stability of metal-doped GenM (n = 9, 10) clusters. AIP Adv. 2015, 5, 067159, DOI: 10.1063/1.4923316Google Scholar582https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFCqsrjF&md5=dab35cb77a704baf154eda9d01b33e88Structures and stability of metal-doped GenM (n = 9, 10) clustersQin, Wei; Lu, Wen-Cai; Xia, Lin-Hua; Zhao, Li-Zhen; Zang, Qing-Jun; Wang, C. Z.; Ho, K. M.AIP Advances (2015), 5 (6), 067159/1-067159/9CODEN: AAIDBI; ISSN:2158-3226. (American Institute of Physics)The lowest-energy structures of neutral and cationic GenM (n = 9, 10; M = Si, Li, Mg, Al, Fe, Mn, Pb, Au, Ag, Yb, Pm and Dy) clusters were studied by genetic algorithm (GA) and first-principles calcns. The calcn. results show that doping of the metal atoms and Si into Ge9 and Ge10 clusters is energetically favorable. Most of the metal-doped Ge cluster structures can be viewed as adding or substituting metal atom on the surface of the corresponding ground-state Gen clusters. However, the neutral and cationic FeGe9,10,MnGe9,10 and Ge10Al are cage-like with the metal atom encapsulated inside. Such cage-like transition metal doped Gen clusters are shown to have higher adsorption energy and thermal stability. Our calcn. results suggest that Ge9,10Fe and Ge9Si would be used as building blocks in cluster-assembled nanomaterials because of their high stabilities. (c) 2015 American Institute of Physics.
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583Jaiswal, S.; Kumar, V. Growth behavior and electronic structure of neutral and anion ZrGen (n = 1–21) clusters. Comput. Theor. Chem. 2016, 1075, 87– 97, DOI: 10.1016/j.comptc.2015.11.013Google Scholar583https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFGnu7nF&md5=bcb052474b01b5a9756b11c804313ba1Growth behavior and electronic structure of neutral and anion ZrGen (n = 1-21) clustersJaiswal, S.; Kumar, VijayComputational & Theoretical Chemistry (2016), 1075 (), 87-97CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)A review. The at. and electronic structure of both neutral and neg. charged ZrGen (n = 1-21) clusters have been studied using ab initio calcns. The at. structures have been identified by comparing the calcd. results of the electronic spectra of the anion clusters with the available photoelectron spectroscopy data. We find that the at. structure of ZrGen cluster can be derived by adding one or more Ge atoms on smaller clusters. Our results show that in some cases a higher energy isomer of ZrGen anion cluster may be present in expts., but the neutral of such an anion is often the lowest energy isomer. This shows the importance of the lowest energy isomer of neutral clusters in expt. In some cases, it is found that two different isomers of the anion of a cluster converge to the identical isomer of the neutral. A large value of the HOMO-LUMO gap as well as binding energy per atom has been calcd. for ZrGe16 neutral cluster and hence, it is more stable and less reactive as compared to other clusters. This agrees with the high abundance of ZrGe16 cluster in expts. The Zr atom is encapsulated in a cage-like structure at a size of thirteen or more Ge atoms. This also agrees with the expts. Further, we have calcd. vertical and adiabatic detachment energies and obtained a low value for ZrGe16 also in agreement with expts. The addn. of an electron to a neutral ZrGe11 cluster, however, changes its at. structure drastically and thus, the calcd. adiabatic and vertical detachment energies for ZrGe11 anion differ very significantly.
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584Siouani, C.; Mahtout, S.; Safer, S.; Rabilloud, F. Structure, stability, and electronic and magnetic properties of VGen (n = 1–19) clusters. J. Phys. Chem. A 2017, 121, 3540– 3554, DOI: 10.1021/acs.jpca.7b00881Google Scholar584https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXmtFCgtbg%253D&md5=ca5ba13090f92490119d5edbac2b2caaStructure, Stability, and Electronic and Magnetic Properties of VGen (n = 1-19) ClustersSiouani, C.; Mahtout, S.; Safer, S.; Rabilloud, F.Journal of Physical Chemistry A (2017), 121 (18), 3540-3554CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We systematically study the equil. geometries and electronic and magnetic properties of Gen+1 and VGen (n = 1-19) clusters using the d. functional theory approach within the generalized gradient approxn. Endohedral structures in which the vanadium atom is encapsulated inside a Gen cage are predicted to be favored for n ≥ 10. The dopant V atom in the Gen clusters has not an immediate effect on the stability of small germanium clusters (n < 6), but it largely contributes to strengthen the stability for n ≥ 7. Our study enhances the large stability of the VGe14 cluster, which presents an Oh symmetry cagelike geometry and a peculiar electronic structure in which the valence electrons of V and Ge atoms are delocalized and exhibit a shell structure assocd. with the quasi-spherical geometry. Consequently, this cluster is proposed to be a good candidate to be used as the building blocks for developing new materials. The cluster size dependence of the stability, the vertical ionization potentials, and electron affinities of Gen+1 and VGen are presented. Magnetic properties and the partial d. of states of the most stable VGen clusters are also discussed.
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585Borshch, N.; Kurganskii, S. Anionic germanium–niobium clusters: atomic structure, mechanisms of cluster formation, and electronic spectra. Russ. J. Phys. Chem. A 2018, 92, 1720– 1726, DOI: 10.1134/S0036024418090078Google Scholar585https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhs1Kgu7fE&md5=4152dc6ff919bf10b4f0f0b39483fac4Anionic Germanium-Niobium Clusters: Atomic Structure, Mechanisms of Cluster Formation, and Electronic SpectraBorshch, N. A.; Kurganskii, S. I.Russian Journal of Physical Chemistry A (2018), 92 (9), 1720-1726CODEN: RJPCBS; ISSN:0036-0244. (Pleiades Publishing, Ltd.)Abstr.: Results from optimizing the at. structure of anionic clusters NbGe-n (n = 8-20) are presented, along with their calcd. electronic spectra. The calcns. are performed within the d. functional theory. The real spatial structures of the clusters are detd. by comparing the calcd. and known exptl. data.
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586Borshch, N.; Kurganskii, S. Atomic structure and electronic properties of anionic germanium–zirconium clusters. Inorg. Mater. 2018, 54, 1– 7, DOI: 10.1134/S0020168518010028Google Scholar586https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjslOqs7w%253D&md5=f8d1f7dcbc2468deb8613bf4fd0dc8d2Atomic Structure and Electronic Properties of Anionic Germanium-Zirconium ClustersBorshch, N. A.; Kurganskii, S. I.Inorganic Materials (2018), 54 (1), 1-7CODEN: INOMAF; ISSN:0020-1685. (Pleiades Publishing, Ltd.)A review. This paper presents spatial structure optimization results and calcd. electronic spectra for ZrGe-n (n = 8-20) anion clusters. Comparison of d.-functional calcn. results and available exptl. data allows us to identify real spatial structures of the clusters. The formation of stable endohedral ZrGe-n clusters is possible for n ≥ 12. The clusters with a smaller no. of germanium atoms predominantly have exohedral structures.
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587Mahtout, S.; Siouani, C.; Rabilloud, F. Growth behavior and electronic structure of noble metal-doped germanium clusters. J. Phys. Chem. A 2018, 122, 662– 677, DOI: 10.1021/acs.jpca.7b09887Google Scholar587https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVSntbjJ&md5=2c9646a512f3a5861fb8721e20bf95ebGrowth Behavior and Electronic Structure of Noble Metal-Doped Germanium ClustersMahtout, Sofiane; Siouani, Chaouki; Rabilloud, FranckJournal of Physical Chemistry A (2018), 122 (2), 662-677CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Structures, energetics and electronic properties of noble metal-doped germanium (MGen with M = Cu, Ag, Au; n = 1-19) clusters are systematically investigated by using the d.-functional theory (DFT) approach. The endohedral structures in which the metal atom is encapsulated inside a germanium cage appear at n = 10 when the dopant is Cu, and n = 12 for M = Ag and Au. While Cu doping enhances the stability of the corresponding germanium frame, the binding energies of AgGen and AuGen are always lower than those of pure germanium clusters. Our results highlight the great stability of the CuGe10 cluster in a D4d structure, and to a lesser extent that of AgGe15 and AuGe15 which exhibits a hollow cage-like geometry. The sphere-type geometries obtained for n = 10-15 present a peculiar electronic structure in which the valence electrons of the noble metal and Ge atoms are delocalized and exhibit a shell structure assocd. with the quasi-spherical geometry. It is found that the coinage metal is able to give both s- and d-type electrons to be reorganized together with the valence electrons of Ge atoms through a pooling of electrons. The cluster size dependence of the stability, the frontier orbital energy gap, the vertical ionization potentials, and electron affinities are given.
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588Triedi, R. K.; Bandyopadhyay, D. Insights of the role of shell closing model and NICS in the stability of NbGen (n = 7–18) clusters: A first-principles investigation. J. Mater. Sci. 2019, 54, 515– 528, DOI: 10.1007/s10853-018-2858-3Google Scholar588https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhs1CmurzN&md5=98c38a1044b50cdd8601f19a6df476bcInsights of the role of shell closing model and NICS in the stability of NbGen (n = 7-18) clusters: a first-principles investigationTriedi, Ravi Kumar; Bandyopadhyay, DebashisJournal of Materials Science (2019), 54 (1), 515-528CODEN: JMTSAS; ISSN:0022-2461. (Springer)The structures, energetics and electronic properties of neutral and cationic Nb-doped Gen (n = 7-18) clusters are systematically investigated using DFT-B3LYP method. The isomers in which the Nb atom is encapsulated inside a germanium cage are relatively stable compared to the exohedral surface doping. The thermodn. stability and chem. activity of the ground-state isomers are analyzed through various energetic parameters. The results highlight the enhanced stability of the neutral NbGe12 hexagonal prism-like structure with D6h symmetry and cationic NbGe16 fullerene isomers. The neg. nucleus-independent chem. shift can explain the enhanced stability of neutral NbGe12. However, the enhanced stability of cationic NbGe16 is explained by shell closing model assocd. with the quasi-spherical geometry with a sequence 1S21P61D101F61G122S22P6IF8IG62D10 following Hund's rule. To understand the effect of hybridization on stability, we have calcd. d. of states (DOS) and projected DOS (PDOS). From PDOS, it is clear that Nb-p and Ge-s and p orbitals are mainly take part in hybridization; however, near below Fermi level, the dominating contribution comes from Nb-d orbitals. In addn., IR and Raman spectra of clusters are also calcd. to explain their vibrational properties of the isomers. Specifically, IR spectrum of the clusters in the range of 12-16 shows the possible application of these clusters in the IR sensing device.
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589Jin, Y.; Tian, Y.; Kuang, X.; Lu, C.; Cabellos, J. L.; Mondal, S.; Merino, G. Structural and electronic properties of ruthenium-doped germanium clusters. J. Phys. Chem. C 2016, 120, 8399– 8404, DOI: 10.1021/acs.jpcc.6b02225Google Scholar589https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltlOmt7o%253D&md5=7f4b5b0a922deb8109742a72460a13eaStructural and Electronic Properties of Ruthenium-Doped Germanium ClustersJin, Yuanyuan; Tian, Yonghong; Kuang, Xiaoyu; Lu, Cheng; Cabellos, Jose Luis; Mondal, Sukanta; Merino, GabrielJournal of Physical Chemistry C (2016), 120 (15), 8399-8404CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We have performed a global min. search for the multicharged ruthenium-doped germanium clusters with the formula RuGenq (n = 2-12, q = -2, - 3) using a particle swarm optimization metaheuristic coupled with d. functional theory computations. Leading candidates for the lowest energy forms have been identified. Among the global min. geometries, going from the size of n = 2 to n = 12, it is perceived that the cluster growth is directed toward the formation of an endohedral aggregate. Particularly, the half-encapsulated structures of RuGe7q and RuGe8q made the bridge between small open-shell (n = 2-6) geometries and the endohedral (n = 9-12) geometries. The endohedral constructions contain the Ru atoms at their interstitial positions. Particularly, the 10-vertex endohedral cluster RuGe102- has an unprecedented 3-connected C3v polyhedral geometry. The pos. values of HOMO energies of global min. anions depict the electronic instability. The countercation effect is discussed to show the compensation of Coulomb repulsion among excess neg. charges. RuGe122- and RuGe123- have S4- and D2d-sym. endohedral shapes, resp., which match with the previous exptl. results. The natural population anal. charge is also examd. to understand the assocd. charge transfers.
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590Tan, Z.; Zhou, T.; Yang, Y. The role of TM’s (M’s) d valence electrons in TM@X12 and M@X12 clusters. AIP Adv. 2016, 6, 125123, DOI: 10.1063/1.4973636Google Scholar590https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXksleitQ%253D%253D&md5=e184120008f84f3c2c745c0572fe13ffThe role of TM's (M's) d valence electrons in TM@X12 and M@X12 clustersTan, Zhiyun; Zhou, Tingwei; Yang, YouchangAIP Advances (2016), 6 (12), 125123/1-125123/9CODEN: AAIDBI; ISSN:2158-3226. (American Institute of Physics)Using the d. functional theory method, the icosahedral TM@X12 (M@X12) clusters (TM=Mn, Tc, Re; M=Zn, Cd, Hg; and X=Sn, Ge), which are composed of Sn12 (Ge12) shell covering a single TM (M) atom, have been systematically examd. to explore the role of TM's (M's) d valence electrons playing in the clusters. The results show that the magnetism originate from the contribution of TM's d valence electrons to TM@X12 clusters, where TM's (M's) d valence electrons are not included in the superat. electronic states to TM@X12 (M@X12) clusters. Taking into account the structural stability (imaginary frequency, binding energy, embedding energy, and core-shell interaction) as well as the chem. stability (HOMO-LUMO gap) after, we proposed that TM@X12 and M@X12 clusters can be assigned as the protyle superatoms. Furthermore, the results suggest that M@C60 clusters can not be superatoms, because their neg. embedding energies and the distance from the center atom (M) to C atom is larger than the sum of their Van Waals radii. Interestingly enough, we may obtain a simple judging method: for a magnetic superatom, the smaller the energy gap between the highest occupied magnetic state (HOMS) and Fermi level or HOMO (MOgap, or MFgap), the easier on the change of its spin magnetic moment. (c) 2016 American Institute of Physics.
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591Middaugh, R.; Muetterties, E. Boron Hydride Chemistry; Academic Press: New York, NY, 1975.Google ScholarThere is no corresponding record for this reference.
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592Liu, C.; Li, L. J.; Popov, I. A.; Wilson, R. J.; Xu, C. Q.; Li, J.; Boldyrev, A. I.; Sun, Z. M. Symmetry reduction upon size mismatch: The non-Icosahedral intermetalloid cluster [Co@Ge12]3–. Chin. J. Chem. 2018, 36, 1165– 1168, DOI: 10.1002/cjoc.201800434Google Scholar592https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVKqu7nN&md5=a78066c0602cd758ca62be47dd991a9cSymmetry Reduction upon Size Mismatch: The Non-Icosahedral Intermetalloid Cluster [Co@Ge12]3-Liu, Chao; Li, Lei-Jiao; Popov, Ivan A.; Wilson, Robert J.; Xu, Cong-Qiao; Li, Jun; Boldyrev, Alexander I.; Sun, Zhong-MingChinese Journal of Chemistry (2018), 36 (12), 1165-1168CODEN: CJOCEV; ISSN:1001-604X. (Wiley-VCH Verlag GmbH & Co. KGaA)A new complex comprising [Co@Ge12]3- cluster core was synthesized through the reaction of CoMe(PMe3)4 and K4Ge9 in ethylenediamine soln. The pseudo-D5d geometry of this cluster can be viewed as structurally derived from an icosahedral cage via Jahn-Teller effect, leading to notable bonding differences from Ih-[M@E12]q- clusters (E = Sn, Pb with q = 2, 3). The [Co@Ge12]3- cluster represents a structural conundrum. On the basis of the geometric considerations it could be viewed as a sandwich complex. However, chem. bonding anal. revealed that there is a direct covalent multicenter bonding between the two pentagons, thus indicating that the structure should be viewed as an elongated icosahedron. Further theor. calcns. on [M@Ge12]3- (M = Rh, Ir, Mt) indicate that similar compds. of larger-size metal atoms can drive the complete transformation of [M@Ge12]3- clusters from icosahedron structure to a sandwich one.
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593Zhou, S.; Yang, X.; Shen, Y.; King, R. B.; Zhao, J. Dual transition metal doped germanium clusters for catalysis of CO oxidation. J. Alloys Compd. 2019, 806, 698– 704, DOI: 10.1016/j.jallcom.2019.07.297Google Scholar593https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsVylsL%252FL&md5=2ef8c76095b475693be5afd0f0e26a7aDual transition metal doped germanium clusters for catalysis of CO oxidationZhou, Si; Yang, Xiaowei; Shen, Yuebo; King, R. Bruce; Zhao, JijunJournal of Alloys and Compounds (2019), 806 (), 698-704CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)CO oxidn. is a crucial reaction to combat environmental pollution caused by fossil fuel burning, industrial exhaust and vehicle emissions. Searching for efficient catalysts made of economical and earth-abundant elements is vital and remains challenging. Here, the authors show for the first time that dual transition metal doped germanium clusters M2Ge12 (M = Cr, Mn, Fe, Co and Ni), which are exptl. accessible, are promising catalysts for low-temp. CO oxidn. Their first-principles calcns. demonstrate that the reaction barrier has a linear relation with the O2 binding strength on the cluster, with the Ni2Ge12 cluster possessing the lowest barrier of 0.35 eV under the Eley-Rideal mechanism. The binding capability and activity are correlated to the d orbital center of two metal dopants in the cluster. Moreover, these M2Ge12 alloy clusters remain stable during the entire reaction process and exhibit satisfactory thermal stability and resistance to segregation. These theor. results not only extend the application area of germanium-based alloy clusters, but also provide useful guidelines for designing inexpensive catalysts for CO oxidn. and tuning their performance by electronic structure engineering.
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594Meloni, G.; Schmude, R., Jr; Kingcade, J., Jr; Gingerich, K. A. Thermodynamic stability of Sn4, Sn5, Sn6, and Sn7 clusters by Knudsen cell mass spectrometry. J. Chem. Phys. 2000, 113, 1852– 1856, DOI: 10.1063/1.481988Google Scholar594https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXltVWis74%253D&md5=8c7a906ad99b2a03cb7c535a973de2f4Thermodynamic stability of Sn4, Sn5, Sn6, and Sn7 clusters by Knudsen cell mass spectrometryMeloni, G.; Schmude, R. W., Jr.; Kingcade, J. E., Jr.; Gingerich, K. A.Journal of Chemical Physics (2000), 113 (5), 1852-1856CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The Knudsen cell mass spectrometric method has been employed to measure the partial pressures of Snn (n = 1-7) under equil. conditions above liq. tin or a tin-gold alloy, contained in a graphite Knudsen cell. From the all-gas analyzed equil. the following atomization enthalpies ΔaH0 (Snn), and enthalpies of formation, ΔfH298.15 (Snn), in kJ mol-1, have been obtained: Sn4, 750.2±14 and 450.6±14; Sn5, 990.2±22 and 512.3±22; Sn6, 1349.7±28 and 452.8±28; Sn7, 1644.2±37 and 460.0±37. The atomization energies are compared with available theor. values.
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595Schäfer, S.; Assadollahzadeh, B.; Mehring, M.; Schwerdtfeger, P.; Schäfer, R. Structure and electric properties of SnN clusters (N = 6–20) from combined electric deflection experiments and quantum theoretical studies. J. Phys. Chem. A 2008, 112, 12312– 12319, DOI: 10.1021/jp8030754Google Scholar595https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlGhs73E&md5=5160a34acb673277bc9974dfdf17ce9fStructure and Electric Properties of SnN Clusters (N = 6-20) from Combined Electric Deflection Experiments and Quantum Theoretical StudiesSchafer, Sascha; Assadollahzadeh, Behnam; Mehring, Max; Schwerdtfeger, Peter; Schafer, RolfJournal of Physical Chemistry A (2008), 112 (48), 12312-12319CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Elec. deflection expts. were performed on neutral SnN clusters (N = 6-20) at different nozzle temps. in combination with a systematic search for the global min. structures and the calcn. of the dielec. properties based on d. functional theory (DFT-B3P86). For smaller tin clusters (N = 6-11), a good agreement between theory and expt. was found. Taking theor. predicted moments of inertia and the body fixed dipole moment into account permits a quant. simulation of the deflected mol. beam profiles. For larger SnN clusters (N = 12-20), distinct differences between theory and expt. are obsd.; i.e., the predicted dipole moments from the quantum chem. calcns. are significantly larger than the exptl. values. The investigation of the elec. susceptibilities at different nozzle temps. indicates that this is due to the dynamical nature of the tin clusters, which increases with cluster size. As a result, even at the smallest nozzle temp. of 40 K, the dipole moments of Sn12-20 are partially quenched. This clearly demonstrates the limits of current elec. deflection expts. for structural detn. and demonstrates the need for stronger cooling of the clusters in future expts.
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596Oger, E.; Kelting, R.; Weis, P.; Lechtken, A.; Schooss, D.; Crawford, N. R.; Ahlrichs, R.; Kappes, M. M. Small tin cluster anions: Transition from quasispherical to prolate structures. J. Chem. Phys. 2009, 130, 124305, DOI: 10.1063/1.3094320Google Scholar596https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjvVels7g%253D&md5=f60ebcb722b3c5f2084d5cea89f03396Small tin cluster anions: Transition from quasispherical to prolate structuresOger, Esther; Kelting, Rebecca; Weis, Patrick; Lechtken, Anne; Schooss, Detlef; Crawford, Nathan R. M.; Ahlrichs, Reinhart; Kappes, Manfred M.Journal of Chemical Physics (2009), 130 (12), 124305/1-124305/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures and energetics of small tin cluster Snn- anions up to n = 15 were detd. by a combination of d.-functional theory and three different exptl. methods: Ion mobility spectrometry, trapped ion electron diffraction, and collision induced dissocn. We find compact, quasispherical structures up to n = 12. Sn12- is a slightly distorted hollow icosahedron while Sn13- to Sn15- have prolate structures, consisting of merged, hollow, in part incomplete, deltahedral subunits: Sn13- consists of a face-sharing pentagonal bipyramid and tricapped trigonal bipyramid, Sn14- comprises a face-sharing dicapped trigonal prism and capped square-antiprism, and Sn15- consists of two face-sharing tricapped trigonal prisms. (c) 2009 American Institute of Physics.
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597Drebov, N.; Oger, E.; Rapps, T.; Kelting, R.; Schooss, D.; Weis, P.; Kappes, M. M.; Ahlrichs, R. Structures of tin cluster cations Sn3+ to Sn15+. J. Chem. Phys. 2010, 133, 224302, DOI: 10.1063/1.3514907Google Scholar597https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFCqurrF&md5=11e163abda6b186b2cf197cef13d8c93Structures of tin cluster cations Sn3+ to Sn15+Drebov, Nedko; Oger, Esther; Rapps, Thomas; Kelting, Rebecca; Schooss, Detlef; Weis, Patrick; Kappes, Manfred M.; Ahlrichs, ReinhartJournal of Chemical Physics (2010), 133 (22), 224302/1-224302/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We employ a combination of ion mobility measurements and an unbiased systematic structure search with d. functional theory methods to study structure and energetics of gas phase tin cluster cations, Snn+, in the range of n = 3-15. For Sn13+ we also carry out trapped ion electron diffraction measurements to ascertain the results obtained by the other procedures. The structures for the smaller systems are most easily described by idealized point group symmetries, although they are all Jahn-Teller distorted: D3h (trigonal bipyramid), D4h (octahedron), D5h (pentagonal bipyramid) for n = 5, 6, and 7. For the larger systems we find capped D5h for Sn8+ and Sn9+, D3h (tricapped trigonal prism) and D4d (bicapped squared antiprism) plus adatoms for n = 10, 11, 14, and 15. A centered icosahedron with a peripheral atom removed is the dominant motif in Sn12+. For Sn13+ the calcns. predict a family of virtually isoenergetic isomers, an icosahedron and slightly distorted icosahedra, which are about 0.25 eV below two C1 structures. The expts. indicate the presence of two structures, one from the Ih family and a prolate C1 isomer based on fused deltahedral moieties. (c) 2010 American Institute of Physics.
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598Lechtken, A.; Drebov, N.; Ahlrichs, R.; Kappes, M. M.; Schooss, D. Communications: Tin cluster anions (Snn–, n = 18, 20, 23, and 25) comprise dimers of stable subunits. J. Chem. Phys. 2010, 132, 211102, DOI: 10.1063/1.3442411Google Scholar598https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXntF2msrs%253D&md5=26f560c66153c0f59c77fc5b3cfc89d7Communications: Tin cluster anions (Snn-, n = 18, 20, 23, and 25) comprise dimers of stable subunitsLechtken, Anne; Drebov, Nedko; Ahlrichs, Reinhart; Kappes, Manfred M.; Schooss, DetlefJournal of Chemical Physics (2010), 132 (21), 211102/1-211102/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The gas phase structures of tin cluster anions Snn- were studied by a combination of trapped ion electron diffraction and d. functional theory calcns. In the size range of n = 18-25 these clusters comprise dimers of stable subunits. In particular Sn18- and Sn20- are homodimers of Sn9 and Sn10 subunits, resp. In Sn23- two Sn10 units are linked by three addnl. bridging atoms and Sn25- is a heterodimer of Sn10 and Sn15 subunits. This rather unexpected growth mode is rationalized by the extraordinary stability of the building blocks Sn9, Sn10 and Sn15. (c) 2010 American Institute of Physics.
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599Wiesel, A.; Drebov, N.; Rapps, T.; Ahlrichs, R.; Schwarz, U.; Kelting, R.; Weis, P.; Kappes, M. M.; Schooss, D. Structures of medium sized tin cluster anions. Phys. Chem. Chem. Phys. 2012, 14, 234– 245, DOI: 10.1039/C1CP22874AGoogle Scholar599https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFGmtbvO&md5=19ea7eb6b2a5a1d1b90eb393c2df599aStructures of medium sized tin cluster anionsWiesel, Anne; Drebov, Nedko; Rapps, Thomas; Ahlrichs, Reinhart; Schwarz, Ulrike; Kelting, Rebecca; Weis, Patrick; Kappes, Manfred M.; Schooss, DetlefPhysical Chemistry Chemical Physics (2012), 14 (1), 234-245CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures of medium sized tin cluster anions Snn- (n = 16-29) were detd. by a combination of d. functional theory, trapped ion electron diffraction and collision induced dissocn. (CID). Mostly prolate structures were found with a structural motif based on only three repeatedly appearing subunit clusters, the Sn7 pentagonal bipyramid, the Sn9 tricapped trigonal prism and the Sn10 bicapped tetragonal antiprism. Sn16- and Sn17- are composed of two face connected subunits. In Sn18--Sn20- the subunits form cluster dimers. For Sn21--Sn23- addnl. tin atoms are inserted between the building blocks. Sn24- and Sn25- are composed of a Sn9 or Sn10 connected to a Sn15 subunit, which closely resembles the ground state of Sn15-. Finally, in the larger clusters Sn26--Sn29- addnl. bridging atoms again connect the building blocks. The CID expts. reveal fission as the main fragmentation channel for all investigated cluster sizes. This rather unexpected "pearl-chain" cluster growth mode is rationalized by the extraordinary stability of the building blocks.
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600Cui, L.-F.; Wang, L.-M.; Wang, L.-S. Evolution of the electronic properties of Snn– clusters (n = 4–45) and the semiconductor-to-metal transition. J. Chem. Phys. 2007, 126, 064505, DOI: 10.1063/1.2435347Google Scholar600https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXitFKqsL4%253D&md5=5b08a929c7e938bef3e94c6ff8f067d4Evolution of the electronic properties of Sn-n clusters (n=4-45) and the semiconductor-to-metal transitionCui, Li-Feng; Wang, Lei-Ming; Wang, Lai-ShengJournal of Chemical Physics (2007), 126 (6), 064505/1-064505/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic structure of Snn- clusters (n = 4-45) was examd. using photoelectron spectroscopy at photon energies of 6.424 eV (193 nm) and 4.661 eV (266 nm) to probe the semiconductor-to-metal transition. Well resolved photoelectron spectra were obtained for small Snn- clusters (n ≤ 25), whereas more congested spectra were obsd. with increasing cluster size. A distinct energy gap was obsd. in the photoelectron spectra of Snn- clusters with n ≤ 41, suggesting the semiconductor nature of small neutral Sn clusters. For Snn- clusters with n ≥ 42, the photoelectron spectra became continuous and no well-defined energy gap was obsd., indicating the onset of metallic behavior for the large Snn clusters. The photoelectron spectra thus revealed a distinct semiconductor-to-metal transition for Snn clusters at n = 42. The spectra of small Sn-n clusters (n ≤ 13) were also compared with those of the corresponding Si-n and Ge-n clusters, and similarities were found between the spectra of Sn-n and those of Gen- in this size range, except for Sn-12, which led to the discovery of stannaspherene (the icosahedral Sn2-12) previously [L. F. Cui [et al.], J. Am. Chem. Soc. 128, 8391(2006)].
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601Majumder, C.; Kumar, V.; Mizuseki, H.; Kawazoe, Y. Atomic and electronic structures of neutral and cation Snn (n = 2–20) clusters: A comparative theoretical study with different exchange-correlation functionals. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 035401, DOI: 10.1103/PhysRevB.71.035401Google Scholar601https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVyrtLs%253D&md5=28521cca98c37a6920fff6df976b1d33Atomic and electronic structures of neutral and cation Snn (n = 2-20) clusters: A comparative theoretical study with different exchange-correlation functionalsMajumder, Chiranjib; Kumar, Vijay; Mizuseki, Hiroshi; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (3), 035401/1-035401/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The at. structures and energetics of neutral and singly pos. charged Snn+ (n = 2-20) clusters have been calcd. using a plane wave pseudopotential method under the framework of the generalized gradient approxn. of the d. functional theory as well as by using the hybrid exchange-correlation functionals viz., BLYP, B3LYP and B3PW91 under the LCAO-MO approach. From the results a systematic anal. has been carried out to obtain the physico-chem. properties such as atomization energies, ionization potentials and fragmentation behavior of the neutral and cation clusters. A comparison with the available exptl. data shows that the results obtained from the B3PW91 functional provide an overall good agreement for all the properties calcd. here. Our calcns. show that the dominant channel for the fragmentation of Snn+, n ≤ 11, clusters is the evapn. of an atom such that the charge remains on the rest of the cluster, while for larger clusters, fission into two subclusters becomes more favorable. Raman and IR vibrational spectra have been calcd. for a few selected clusters. These confirm the structural stabilities of the clusters and can provide a way to identify the at. structures from expts.
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602Wu, D.; Du, Q.; Wu, X.; Shi, R.; Sai, L.; Liang, X.; Huang, X.; Zhao, J. Evolution of atomic structures of SnN, and SnN-, and SnNCl- clusters (N = 4-20): Insight from ab initio calculations. J. Chem. Phys. 2019, 150, 174304, DOI: 10.1063/1.5095437Google Scholar602https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXptFGqsrs%253D&md5=00b589b6d40fc1b139dbda05923fd62bEvolution of atomic structures of SnN, SnN- , and SnNCl- clusters (N = 4-20): Insight from ab initio calculationsWu, Di; Du, Qiuying; Wu, Xue; Shi, Ruili; Sai, Linwei; Liang, Xiaoqing; Huang, Xiaoming; Zhao, JijunJournal of Chemical Physics (2019), 150 (17), 174304/1-174304/15CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)An unbiased global search was employed to explore the low-energy structures of SnN, SnN-, and SnNCl- clusters with N = 4-20 atoms based on the genetic algorithm combined with d. functional theory calcns. Some unprecedented low-energy isomers are reported for SnN and SnNCl- clusters. The theor. electronic properties such as binding energy per atom, ionization potential, adiabatic detachment energy, and vertical detachment energy compare well with the exptl. data. Based on the equil. structures, the simulated photoelectron spectra are in good agreement with the exptl. data in the range of N = 4-20. With addn. of a Cl atom on the SnN- cluster, which causes almost no rearrangement on the structural framework, the first peaks in all original photoelectron spectra of SnN- clusters disappear and other peaks nearly retain the original feature at most sizes. (c) 2019 American Institute of Physics.
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603Cui, L.-F.; Huang, X.; Wang, L.-M.; Zubarev, D. Y.; Boldyrev, A. I.; Li, J.; Wang, L.-S. J. Am. Chem. Soc. 2006, 128, 8390– 8391, DOI: 10.1021/ja062052fGoogle Scholar603https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlvFegtbY%253D&md5=af1cd64b098b0f2ce175ae98458d5693Sn122-: StannasphereneCui, Li-Feng; Huang, Xin; Wang, Lei-Ming; Zubarev, Dmitry Yu.; Boldyrev, Alexander I.; Li, Jun; Wang, Lai-ShengJournal of the American Chemical Society (2006), 128 (26), 8390-8391CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Stannaspherene. The Sn122- cluster is discovered to be a highly stable and highly sym. icosahedral cage bonded by four delocalized radial π bonds and nine delocalized on-sphere σ bonds from the 5p orbitals of the Sn atoms. It has a diam. of 6.1 Å, with a large empty interior vol., and can host most transition metal atoms inside, giving rise to a large class of endohedral chem. building blocks for cluster-assembled nanomaterials.
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604Chen, D.-L.; Tian, W. Q.; Feng, J.-K.; Sun, C.-C. Evidence for d-orbital aromaticity in Sn- and Pb-based clusters: Is Sn122- aromatic?. J. Phys. Chem. A 2007, 111, 8277– 8280, DOI: 10.1021/jp073646nGoogle Scholar604https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXot12gsr0%253D&md5=f8624d7332db67d31ac0e66ac0808a01Evidence for d-Orbital Aromaticity in Sn- and Pb-Based Clusters: Is Sn122- Aromatic?Chen, De-Li; Tian, Wei Quan; Feng, Ji-Kang; Sun, Chia-ChungJournal of Physical Chemistry A (2007), 111 (33), 8277-8280CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The electronic structures and stabilities of pure M12- and M122- were systematically investigated within d. functional theory. The nucleus-independent chem. shifts (NICSs) of Ih Sn122- and Pb122- are -5.0 and -20.7 ppm, resp., based on B3LYP/aug-cc-pVDZ-PP predictions, whereas the NICS of Sn122- is predicted to be 1.1 ppm by B3LYP/LanL2DZ. A startling conclusion is that the NICS4d of Sn122- and NICS5d of Pb122- are -5.0 and -7.5 ppm, resp., suggesting the significant contribution of the inner d orbitals to the total NICS values. This provides the first quant. evidence for the existence of "d-orbital aromaticity" in Sn- and Pb-based clusters with three-dimensional structures. The d orbitals also contribute to the total NICSs of the K-coordinated clusters. The NICS predictions suggest that larger basis sets including d-orbitals are needed to analyze the aromaticity of some main-group-metal-based clusters (e.g., Sn- and Pb-based clusters) to obtain accurate predictions.
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605Breaux, G. A.; Hillman, D. A.; Neal, C. M.; Jarrold, M. F. Stable copper-tin cluster compositions from high-temperature annealing. J. Phys. Chem. A 2005, 109, 8755– 8759, DOI: 10.1021/jp0501650Google Scholar605https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpvFCmsrw%253D&md5=eb8cccf837332cda06d3b7f890ae6f30Stable copper-tin cluster compositions from high-temperature annealingBreaux, Gary A.; Hillman, Damon A.; Neal, Colleen M.; Jarrold, Martin F.Journal of Physical Chemistry A (2005), 109 (39), 8755-8759CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Copper-doped tin clusters can be thermally annealed to give much more stable compns. with a substantially higher copper/tin ratio. The annealed clusters are only prominent over a narrow range of compns. as CuSn10-15+, Cu2Sn12-18+, Cu3Sn15-21+, Cu4Sn18-(24)+, and Cu5Sn21-(27)+. These compns. are close to those found for WmSin+ clusters and raise the possibility that the CumSnn+ clusters have core-shell geometries like those proposed for the WmSin+ clusters. Increasing the no. of copper atoms causes a change in the dissocn. pattern from the fission processes characteristic of semiconductor clusters to the expulsion of individual atoms, which usually occurs for metal clusters. The change in the fragmentation pattern may result because the clusters rich in copper melt before they dissoc., while the tin clusters dissoc. directly from a solid-like phase.
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606Cui, L. F.; Huang, X.; Wang, L. M.; Li, J.; Wang, L. S. Endohedral stannaspherenes M@Sn12–: A rich class of stable molecular cage clusters. Angew. Chem., Int. Ed. 2007, 46, 742– 745, DOI: 10.1002/anie.200603226Google Scholar606https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlersrw%253D&md5=3e1b46903ad72857470bfdc69a3297deEndohedral stannaspherenes M@Sn12-: a rich class of stable molecular cage clustersCui, Li-Feng; Huang, Xin; Wang, Lei-Ming; Li, Jun; Wang, Lai-ShengAngewandte Chemie, International Edition (2007), 46 (5), 742-745, S742/1-S742/5CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Trapped in a cage: Combined exptl. and theor. evidence shows that the stannaspherene Sn122- can trap a transition-metal or f-element atom (green) to form a stable endohedral cluster. The central metal atom induces very little distortion in the icosahedral cage. The clusters can be viewed as superatoms for use in materials with tunable magnetic, electronic, and chem. properties.
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607Rohrmann, U.; Schäfer, S.; Schäfer, R. Size- and temperature-dependent magnetic response of molecular cage clusters: Manganese-doped tin clusters. J. Phys. Chem. A 2009, 113, 12115– 12121, DOI: 10.1021/jp906140bGoogle Scholar607https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1eltrbE&md5=5c2792b03f6cbdda80a79f22a1704ec9Size- and Temperature-Dependent Magnetic Response of Molecular Cage Clusters: Manganese-Doped Tin ClustersRohrmann, Urban; Schaefer, Sascha; Schaefer, RolfJournal of Physical Chemistry A (2009), 113 (44), 12115-12121CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Endohedral clusters, formed by incorporating a single Mn atom into a cage of tin atoms, were generated in the gas phase. Mass spectrometry reveals that a cage size of 10 tin atoms is necessary for the efficient incorporation of one Mn atom. Some of the cluster compds. with one Mn atom attached to the tin clusters display large intensities compared to the pure tin clusters, indicating that the compd. clusters are particularly stable. The manganese-doped tin cluster assemblies Mn@Sn12, Mn@Sn13, and Mn@Sn15 were further analyzed within a mol. beam magnetic deflection expt. Although the effect of the magnetic field on the behavior of Mn@Sn12 is quite different from that of Mn@Sn13 and Mn@Sn15, the magnetic dipole moments are the same within the uncertainty of the measurements. Magnetic dipole moments were found in close agreement with the spin quantum no. S = 5/2 predicted by theory for Mn@Sn12, indicating that the magnetic moment of the Mn atom is not quenched. This supports the idea that within a tin cluster cage a single Mn atom can be encapsulated, giving endohedral clusters consisting of a central Mn2+ ion surrounded by a particularly stable Zintl-ion cage SnN2-. The obsd. mol. beam profiles indicate that at a nozzle temp. of 55 K the magnetic moment is strongly locked to the mol. framework of Mn@Sn12; in contrast, the magnetic moment of Mn@Sn13 and Mn@Sn15 tends to align with the magnetic field. The expts. therefore demonstrate that the size of a presumably nonmagnetic cluster cage might have a fundamental influence on the magnetization dynamics of paramagnetic species. The influence of vibrational excitation on the Stern-Gerlach profile of Mn@Sn12 is further analyzed, and the behavior of Mn@Sn12 at elevated nozzle temps. changes continuously toward a nonlocked moment, pointing to size- and temp.-dependent magnetization dynamics.
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608Rohrmann, U.; Schäfer, R. Stern-Gerlach experiments on Fe@Sn12: Magnetic response of a Jahn–Teller distorted endohedrally doped molecular cage cluster. J. Phys. Chem. C 2015, 119, 10958– 10961, DOI: 10.1021/jp510972kGoogle Scholar608https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXlsFChsA%253D%253D&md5=13c135686743a4ce9e5eaadd9423f5bdStern-Gerlach Experiments on Fe@Sn12: Magnetic Response of a Jahn-Teller Distorted Endohedrally Doped Molecular Cage ClusterRohrmann, Urban; Schaefer, RolfJournal of Physical Chemistry C (2015), 119 (20), 10958-10961CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The magnetic response of the Fe@Sn12 cluster was studied by magnetic beam deflection expts. In contrast to Mn@Sn12, the mol. beam of this cluster is deflected almost exclusively toward increasing field, also at low temps., supposable due to Jahn-Teller induced distortions of the Sn cage. The magnitude of the magnetic dipole moment is extd. from the shift of the beam profile and provides evidence for a (partially quenched) contribution of electronic orbital angular momentum to the magnetic dipole moment.
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609Fuchs, T. M.; Schäfer, R. Double Stern-Gerlach experiments on Mn@Sn12: Refocusing of a paramagnetic superatom. Phys. Rev. A: At., Mol., Opt. Phys. 2018, 98, 063411, DOI: 10.1103/PhysRevA.98.063411Google ScholarThere is no corresponding record for this reference.
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610Fuchs, T. M.; Schäfer, R. Effect of vibrational excitation and spin-rotation coupling on Stern-Gerlach experiments: A detailed case study on GdSn15 as an asymmetric rotor. Phys. Rev. A: At., Mol., Opt. Phys. 2019, 100, 012512, DOI: 10.1103/PhysRevA.100.012512Google ScholarThere is no corresponding record for this reference.
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611Gleditzsch, M.; Fuchs, T. M.; Schäfer, R. N-doping at the sub-nanoscale: Dielectric and magnetic eesponse of neutral phosphorus-doped tin clusters. J. Phys. Chem. A 2019, 123, 1434– 1444, DOI: 10.1021/acs.jpca.8b12049Google Scholar611https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXisFyktLY%253D&md5=18cf22a441c4ce706f2c25e236bfa09fN-Doping at the Sub-Nanoscale: Dielectric and Magnetic Response of Neutral Phosphorus-Doped Tin ClustersGleditzsch, Martin; Fuchs, Thomas M.; Schaefer, RolfJournal of Physical Chemistry A (2019), 123 (7), 1434-1444CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Doped semiconductors play a prevalent role in all aspects of modern technol. Because of the trend for smaller and smaller devices, we have investigated N-doping at the sub-nanoscale. For that purpose, we present mol. beam elec. and magnetic deflection expts. on SnNP (N = 6-12) and SnNP2 (N = 7-12) clusters combined with quantum chem. calcns. and classical beam deflection simulations. The theor. identified and exptl. confirmed global min. structures resemble the valence-isoelectronic pure tin anions/dianions very closely, while each phosphorus dopant occupies the site of a tin atom. In Stern-Gerlach expts., the single-doped clusters show a partial atom-like deflection behavior with total electronic angular momentum J = 1/2 whereas the results for the double-doped species suggest singlet states. This is in full agreement with quantum chem. results. The effect of vibrational excitation on magnetic and elec. deflection expts. is examd. Our results provide insight into how the elec., magnetic, and structure properties are affected by n-doping at the sub-nanoscale.
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612Gleditzsch, M.; Pašteka, L. F.; Götz, D. A.; Shayeghi, A.; Johnston, R. L.; Schäfer, R. Gold doping of tin clusters: exo-vs. endohedral complexes. Nanoscale 2019, 11, 12878– 12888, DOI: 10.1039/C9NR03233AGoogle Scholar612https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXht1Kgtr%252FK&md5=d127655532ec13b724376e2475cd3647Gold doping of tin clusters: exo- vs. endohedral complexesGleditzsch, Martin; Pasteka, Lukas F.; Goetz, Daniel A.; Shayeghi, Armin; Johnston, Roy L.; Schaefer, RolfNanoscale (2019), 11 (27), 12878-12888CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)We present mol. beam elec. deflection expts. on neutral gold-doped tin clusters. The exptl. SnNAu (N = 6-16) cluster beam profiles are interpreted by means of classical trajectory simulations supplied, with cluster structures generated by a genetic algorithm based on d. functional theory. The combined exptl. and theor. anal. confirms that at least nine tin atoms are necessary to form a cage that is capable of encapsulating a gold atom, with high symmetry only marginally distorted by the gold atom. Two-component DFT calcns. reveal that for some clusters spin-orbit effects are necessary to properly describe these species. Partial charge anal. methods predict the presence of charge transfer effects from the tin host to the dopant, resulting in a neg. charged gold atom.
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613Gleditzsch, M.; Jäger, M.; Pašteka, L. F.; Shayeghi, A.; Schäfer, R. Doping effects on the geometric and electronic structure of tin clusters. Phys. Chem. Chem. Phys. 2019, 21, 24478– 24488, DOI: 10.1039/C9CP05124DGoogle Scholar613https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitV2mtr7I&md5=876811dc62b78f04ccefedc39b16224cDoping effects on the geometric and electronic structure of tin clustersGleditzsch, Martin; Jaeger, Marc; Pasteka, Lukas F.; Shayeghi, Armin; Schaefer, RolfPhysical Chemistry Chemical Physics (2019), 21 (44), 24478-24488CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Mol. beam elec. deflection expts. on neutral single copper-doped tin clusters are presented at different cryogenic nozzle temps. The exptl. cluster beam profiles SnNCu (N = 9-16) are compared with classical rotational dynamic simulations of globally optimized structures obtained by a genetic algorithm based on d. functional theory. The formation of endohedral complexes with comparable geometry to manganese- and gold-doped tin is confirmed. Theor. methods predict ionic structures of the type Cuδ-@SnNδ+ with electron transfer from the tin cage to the central copper dopant. This behavior is discussed based on a MO picture particularly with respect to other transition metal tetrel complexes.
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614Liu, C.; Jin, X.; Li, L.; Xu, J.; McGrady, J.; Sun, Z. Synthesis and structure of a family of rhodium polystannide clusters [Rh@Sn10]3–, [Rh@Sn12]3–, [Rh2@Sn17]6– and the first triply-fused stannide, [Rh3@Sn24]5–. Chem. Sci. 2019, 10, 4394– 4401, DOI: 10.1039/C8SC03948HGoogle Scholar614https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXksFemtbk%253D&md5=c581fe95eacc5dac804796b585bfa3d1Synthesis and structure of a family of rhodium polystannide clusters [Rh@Sn10]3-, [Rh@Sn12]3-, [Rh2@Sn17]6- and the first triply-fused stannide, [Rh3@Sn24]5-Liu, Chao; Jin, Xiao; Li, Lei-Jiao; Xu, Jun; McGrady, John E.; Sun, Zhong-MingChemical Science (2019), 10 (16), 4394-4401CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)Through relatively subtle changes in reaction conditions, we have been able to isolate four distinct Rh/Sn cluster compds., [Rh@Sn10]3-, [Rh@Sn12]3-, [Rh2@Sn17]6- and [Rh3@Sn24]5-, from the reaction of K4Sn9 with [(COE)2Rh(μ-Cl)]2(COE = cyclooctene). The last of these has a hitherto unknown mol. topol., an edge-fused polyhedron contg. three Rh@Sn10 subunits, and represents the largest endohedral Group 14 Zintl cluster yet to have been isolated from soln. DFT has been used to place these new species in the context of known cluster chem. ESI-MS expts. on the reaction mixts. reveal the ubiquitous presence of {RhSn8} fragments that may play a role in cluster growth.
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615Tai, T. B.; Tam, N. M.; Nguyen, M. T. Evolution of structures and stabilities of zinc-doped tin clusters SnnZn, n = 1–12. Three-dimensional aromaticity of the magic clusters Sn10Zn and Sn12Zn. Chem. Phys. 2011, 388, 1– 8, DOI: 10.1016/j.chemphys.2011.06.041Google Scholar615https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtF2rsLfF&md5=11deebbd68e7181fb0bf5c53cf7b85e1Evolution of structures and stabilities of zinc-doped tin clusters SnnZn, n = 1-12. Three-dimensional aromaticity of the magic clusters Sn10Zn and Sn12ZnTai, Truong-Ba; Tam, Nguyen-Minh; Nguyen, Minh-ThoChemical Physics (2011), 388 (1-3), 1-8CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)Small zinc-doped tin clusters SnnZn, n = 1-12, are studied using DFT and CCSD(T) methods. The isomers are located using a stochastic search algorithm. The growth mechanism can be formulated as follows: (i) small clusters SnnZn with n ≤ 8 are formed by capping Zn on a surface of Snn, (ii) a competition between exohedral and endohedral structures appears at n = 9 and 10, from which the endohedral structures become predominant, (iii) for n = 11 and 12, the clusters are formed by encapsulating Zn into the empty cages Snn. Icosahedral Sn12Zn (I h) and Sn10Zn (D 4d) are magic clusters with large HOMO-LUMO gaps, high binding energies and embedding energies. While both Sn12Zn and Sn10Zn clusters can be considered to be spherically arom. with 8 valence π-electrons that satisfy the electron count rule of 2(N + 1)2, the enhanced stability of Sn12Zn (I h) can further be rationalized in terms of its closed crystal field splitting shell.
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616Bai, Y.-J.; Deng, K.-M.; Shaoa, J.-L.; Xua, N. Structures, stabilities and electronic properties of MSn10 (M = Li, Be, B, Ca). J. At. Mol. Sci. 2018, 5, 217– 230, DOI: 10.4208/jams.030114.052814aGoogle ScholarThere is no corresponding record for this reference.
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617Zdetsis, A. D. Rationalizing and functionalizing stannaspherene: Very stable stannaspherene “alloys”. J. Chem. Phys. 2009, 131, 224310, DOI: 10.1063/1.3267046Google Scholar617https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFGjt73K&md5=88b26c179e667ee1808800acaed036ccRationalizing and functionalizing stannaspherene: Very stable stannaspherene "alloys"Zdetsis, Aristides D.Journal of Chemical Physics (2009), 131 (22), 224310/1-224310/11CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)It is illustrated here by ab initio calcns. based on d. functional theory and other high level methods that the high stability of the icosahedral Sn122- dianion known as stannaspherene, reflects stability toward ionization rather than cohesion. This could be also connected with novel fluxional rearrangements and paths of Sn111- leading eventually to Sn122- involving charge transfer. In view of the very similar structural and electronic properties with the corresponding isovalent borane (B12H12)2-, it is demonstrated that stannaspherene can be further rationalized and functionalized on the basis of an isolobal analogy between group 14 clusters and isovalent boranes, carboranes, and bisboranes. Such analogy is of the same nature with analogous isolobal and isovalent similarities between silicon, hydrogenated silicon-carbon clusters and deltahedral boranes and carboranes, which the present author, scoptically and synoptically, has described as the "boron connection.". It is predicted and verified theor.: First, that the isovalent Bi2Sn10 and Sb2Sn10 clusters, considered as the microscopic analogs of tin-bismuth alloys, are very stable (more stable than stannaspherene itself) very sym. and isolobal to Sn122-; and second, that embedded clusters of the form M@Sn122- and M@Bi2Sn10 (M = Pt,Pd) are very stable and highly sym. (Ih and D5d resp.) with large HOMO-LUMO gaps and very large embedding energies of the order of 5-6 eV. It is furthermore predicted that Pt@Sn122- and Pt@Bi2Sn10 can be synthesized in view of their higher stability compared to Pt@Pb122- which has already been synthesized. The marginal energy difference of 0.03 eV between the meta- and the para-isomer of Bi2Sn10 indicates a fluxional behavior with respect to Bi-Sn interchange which should be related with the Sn121- fluxionality leading eventually to Sn122-. This rearrangement is also assocd. with a strange arom. behavior. The same type of Bi-Sn fluxionality is also encountered in higher energy structures. Due to the "inert pair effect" in tin, the validity of the isolobal analogy is much stronger and fully valid compared to isovalent species based on germanium or silicon, such as Ge122-, Bi22Ge10, and Ge10C2H2 and Si122-, Bi2Si10, and Si10C2H2. The present ideas are in full agreement with available expts. and suggest even further functionalization of stannaspherene, analogous to metalloboranes, metallocarboranes, and stannaboranes with several potential applications. (c) 2009 American Institute of Physics.
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618Matxain, J. M.; Piris, M.; Formoso, E.; Mercero, J. M.; Lopez, X.; Ugalde, J. M. Endohedral stannaspherenes Mn@Sn12 and its dimer: Ferromagnetic or antiferromagnetic?. ChemPhysChem 2007, 8, 2096– 2099, DOI: 10.1002/cphc.200700428Google Scholar618https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtF2qtbnL&md5=24f37ea335b1b28cb4f4e8c999bf6984Endohedral stannaspherenes Mn@Sn12 and its dimer: ferromagnetic or antiferromagnetic?Matxain, Jon M.; Piris, Mario; Formoso, Elena; Mercero, Jose M.; Lopez, Xabier; Ugalde, Jesus M.ChemPhysChem (2007), 8 (14), 2096-2099CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)The structural and electronic properties of the neutral Mn@Sn12 cluster and its dimer are investigated. All geometries were fully optimized using the hybrid metaGGA functional MPWB1K within d. functional theory, combined with the relativistic compact effective core potentials and shared-exponent basis set of Stevens et al. The estns. indicate that the inner manganese atom loses two valence electrons to the cage upon encapsulation. This confirms the assumption that endohedral stannaspherenes contain the dianionic Sn122- cage moiety. Based on the magnetic exchange coupling consts., J, of three isomers of the [Mn@Sn12]2 dimer, an anti- ferromagnetic interaction is favored.
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619Kandalam, A. K.; Chen, G.; Jena, P. Unique magnetic coupling between Mn doped stannaspherenes Mn@Sn12. Appl. Phys. Lett. 2008, 92, 143109, DOI: 10.1063/1.2896608Google Scholar619https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXkvFyqtr8%253D&md5=e45171ebf0b770172f17d00870e74c8cUnique magnetic coupling between Mn doped stannaspherenes Mn@Sn12Kandalam, Anil K.; Chen, Gang; Jena, PuruApplied Physics Letters (2008), 92 (14), 143109/1-143109/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)We report the d. functional theory based study of the interaction between two Mn doped stannaspherenes (Mn@Sn12). The calcd. results show that Mn@Sn12 cluster is not only highly stable and carry a high magnetic moment, but these clusters retain their structural identity and form a stable dimer cluster. Most importantly, the magnetic coupling between the Mn@Sn12 clusters depends on the relative orientation of the cages. In addn., ab initio mol. dynamics calcns. show that the dimer cluster is stable at room temp. These results are expected to trigger further investigations on highly stable bimetallic magnetic cage complexes. (c) 2008 American Institute of Physics.
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620Chen, X.; Deng, K.; Liu, Y.; Tang, C.; Yuan, Y.; Tan, W.; Wang, X. The geometric, optical, and magnetic properties of the endohedral stannaspherenes M@Sn12 (M = Ti, V, Cr, Mn, Fe, Co, Ni). J. Chem. Phys. 2008, 129, 094301, DOI: 10.1063/1.2969111Google Scholar620https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtV2gs7%252FM&md5=23aa8efe1c0e44cf8f43019beb4f769aThe geometric, optical, and magnetic properties of the endohedral stannaspherenes M@Sn12 (M=Ti, V, Cr, Mn, Fe, Co, Ni)Chen, Xuan; Deng, Kaiming; Liu, Yuzhen; Tang, Chunmei; Yuan, Yongbo; Tan, Weishi; Wang, XinJournal of Chemical Physics (2008), 129 (9), 094301/1-094301/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometric, optical, and magnetic properties of the M@Sn12 clusters (M = Ti, V, Cr, Mn, Fe, Co, Ni) are studied using the relativistic d.-functional method. The geometric optimization shows that the ground states of these clusters are probably very close to the Ih structure. Our calcns. demonstrate that the optical gaps of the M@Sn12 can be tuned from IR to green, and the magnetic moments of them vary from 2 μB to 5 μB by doping d transition metal atoms into Sn12 cage, suggesting that M@Sn12 could be a new class of potential nanomaterials with tunable magnetic and optical properties. (c) 2008 American Institute of Physics.
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621Dognon, J.-P.; Clavaguéra, C.; Pyykkö, P. Chemical properties of the predicted 32-electron systems Pu@Sn12 and Pu@Pb12. C. R. Chim. 2010, 13, 884– 888, DOI: 10.1016/j.crci.2010.05.012Google Scholar621https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXpvFKlu74%253D&md5=0aebab2367d82aa7269ceae9568ec0d6Chemical properties of the predicted 32-electron systems Pu@Sn12 and Pu@Pb12Dognon, Jean-Pierre; Clavaguera, Carine; Pyykkoe, PekkaComptes Rendus Chimie (2010), 13 (6-7), 884-888CODEN: CRCOCR; ISSN:1631-0748. (Elsevier Masson SAS)The electronic structures, as well as spectroscopic and thermodn. properties of the title Pu@M12 clusters, are considered at the d. functional theory level. In both cases, a Pu2+ ion is encapsulated in an icosahedral, stanna- or plumbaspherene M2-12 cage. As suggested before for M = Pb, both systems are reported to follow a 32-electron principle for the central atom.
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622Joshi, M.; Chandrasekar, A.; Ghanty, T. K. Theoretical investigation of M@Pb122– and M@Sn122– zintl clusters (M = Lrn+, Lun+, La3+, Ac3+ and n = 0, 1, 2, 3). Phys. Chem. Chem. Phys. 2018, 20, 15253– 15272, DOI: 10.1039/C8CP01056KGoogle Scholar622https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXos1Wgurg%253D&md5=8dfeee6277c01dcc88d3e3d491ad9b16Theoretical investigation of M@Pb122- and M@Sn122- Zintl clusters (M = Lrn+, Lun+, La3+, Ac3+ and n = 0, 1, 2, 3)Joshi, Meenakshi; Chandrasekar, Aditi; Ghanty, Tapan K.Physical Chemistry Chemical Physics (2018), 20 (22), 15253-15272CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The positions of lawrencium (Lr), lutetium (Lu), actinium (Ac) and lanthanum (La) in the periodic table have been a controversial topic for quite some time. According to studies carried out by different groups with their justifications, these elements may potentially be placed in the d-block, p-block or all four in a 15 element f-block. The present work looks into this issue from a new perspective, which involves encapsulation of these four elements into Zintl ion clusters, Pb122- and Sn122-, followed by the detn. of the structural, thermodn. and electronic properties of these endohedral M@Pb122- and M@Sn122- clusters (M = Lrn+, Lun+ with n = 0, 1, 2, 3) using first principles based d. functional theory (DFT). These parameters are compared with similar clusters encapsulated La3+ and Ac3+ ions in order to seek out similarities and differences to draw conclusions about their placement in the periodic table. For the first time the structural, energetic, and electronic properties of these metal atom/ion encapsulated Pb122- and Sn122- clusters have been investigated thoroughly. Structural parameters such as bond distances, geometry and symmetry, electronic properties viz. the d. of states, the MO ordering, the electron localization function, bond crit. point properties and charge distributions have been analyzed. Addnl., the thermodn. property of the binding energy during the encapsulation process has also been calcd. All M@Pb12+ and M@Sn12+ (M = Lr and Lu) clusters form stable 18 bonding electron magic no. systems with shell closing. They show neg. values of binding energy and relatively large HOMO-LUMO energy gaps indicating the stability of such clusters. All the calcd. parameters for Lr encapsulated clusters closely match with the corresponding calcd. parameters of Lu encapsulated clusters, confirming the similarity between Lr and Lu metal atoms in various oxidn. states, though their at. ground state valence electronic configurations are different. The effect of spin orbit coupling has also been investigated using the ZORA approach. It is interesting to discover that La and Ac showed striking similarities to Lr and Lu with respect to all the properties investigated and have formed a stable 18-electron system.
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623Wang, J. Q.; Stegmaier, S.; Wahl, B.; Faessler, T. F. Step-by-step synthesis of the endohedral stannaspherene [Ir@Sn12]3– via the capped cluster anion [Sn9Ir(cod)]3–. Chem. - Eur. J. 2010, 16, 1793– 1798, DOI: 10.1002/chem.200902815Google Scholar623https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVKjtrc%253D&md5=7a88a02eb18eebffa65e5346b49ebae0Step-by-Step Synthesis of the Endohedral Stannaspherene [Ir@Sn12]3- via the Capped Cluster Anion [Sn9Ir(cod)]3-Wang, Jian-Qiang; Stegmaier, Saskia; Wahl, Bernhard; Faessler, Thomas F.Chemistry - A European Journal (2010), 16 (6), 1793-1798, S1793/1-S1793/4CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The endohedral stannaspherene cluster anion [Ir@Sn12]3- was synthesized in two steps. The reaction of K4Sn9 with [IrCl(cod)]2 (cod: 1,5-cyclooctadienyl) in ethylenediamine (en) soln. first yielded the [K(2,2,2-crypt)]+ salt (2,2,2-crypt: 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) of the capped cluster anion [Sn9Ir(cod)]3-. Subsequently, crystals of this compd. were dissolved in en, followed by the addn. of triphenylphosphine or 1,2-bis(diphenylphosphino)ethane and treatment at elevated temps. [Ir@Sn12]3- was obtained and characterized as the [K(2,2,2-crypt)]+ salt. The isolation of [Sn9Ir(cod)]3- as an intermediate product establishes that the formation of the stannaspherene [Ir@Sn12]3- occurs through the oxidn. of [Sn9Ir(cod)]3-. Among the structurally characterized tetrel cluster anions, [Ir@Sn12]3- is a unique example of a stannaspherene, and one of the rare spherical clusters encapsulating a metal atom that is not a member of Group 10. Single-crystal structure detn. shows that the novel Zintl ion cluster has nearly perfect icosahedral Ih point symmetry.
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624Shvartsburg, A. A.; Jarrold, M. F. Transition from covalent to metallic behavior in group-14 clusters. Chem. Phys. Lett. 2000, 317, 615– 618, DOI: 10.1016/S0009-2614(99)01416-5Google Scholar624https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhtFaht7s%253D&md5=f5232c1cc7a5a07e4aff11ef836c9a1dTransition from covalent to metallic behavior in Group IVA element clustersShvartsburg, A. A.; Jarrold, M. F.Chemical Physics Letters (2000), 317 (6), 615-618CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)We have probed the structures of Pbn cations up to n = 32 using ion mobility measurements. These species assume compact near-spherical morphologies for all sizes studied. This behavior is characteristic of clusters of the metallic elements. Silicon, germanium, and tin clusters in the same size range have previously been found to adopt prolate geometries produced by stacking tricapped trigonal prism units. So the transition to 'normal' metal cluster growth in the Group IVA elements occurs between tin and lead, one row lower than the transition from covalent to metallic bonding in the bulk solids under ambient conditions.
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625Senz, V.; Fischer, T.; Oelßner, P.; Tiggesbäumker, J.; Stanzel, J.; Bostedt, C.; Thomas, H.; Schöffler, M.; Foucar, L.; Martins, M. Core-hole screening as a probe for a metal-to-nonmetal transition in lead clusters. Phys. Rev. Lett. 2009, 102, 138303, DOI: 10.1103/PhysRevLett.102.138303Google Scholar625https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXktFSjs7c%253D&md5=836c8ef189545af5412b58357b573e67Core-Hole Screening as a Probe for a Metal-to-Nonmetal Transition in Lead ClustersSenz, V.; Fischer, T.; Oelssner, P.; Tiggesbaumker, J.; Stanzel, J.; Bostedt, C.; Thomas, H.; Schoeffler, M.; Foucar, L.; Martins, M.; Neville, J.; Neeb, M.; Moeller, Th.; Wurth, W.; Ruehl, E.; Doerner, R.; Schmidt-Boecking, H.; Eberhardt, W.; Gantefoer, G.; Treusch, R.; Radcliffe, P.; Meiwes-Broer, K.-H.Physical Review Letters (2009), 102 (13), 138303/1-138303/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Metal clusters serve as model systems to study basic problems of electronic correlation. Vacuum UV light from the free-electron laser FLASH ionizes 5d electrons from mass-sepd. neg. charged clusters, thus transiently leading to core-ionized neutral systems. Shielding of the core hole affects the electron binding energy. From the strong deviation from expectations of the metallic droplet and jellium models the authors conclude on reduced electronic shielding once the cluster size falls .ltorsim.20 atoms. This suggests a metal-to-nonmetal transition, in agreement with previous local d. approxn. calcns.
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626Götz, D.; Shayeghi, A.; Johnston, R.; Schwerdtfeger, P.; Schäfer, R. Influence of spin-orbit effects on structures and dielectric properties of neutral lead clusters. J. Chem. Phys. 2014, 140, 164313, DOI: 10.1063/1.4872369Google Scholar626https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2cnptFyktA%253D%253D&md5=74ef322c32955da4fbf7df57b215d11fInfluence of spin-orbit effects on structures and dielectric properties of neutral lead clustersGotz D A; Shayeghi A; Schafer R; Johnston R L; Schwerdtfeger PThe Journal of chemical physics (2014), 140 (16), 164313 ISSN:.Combining molecular beam electric deflection experiments and global optimization techniques has proven to be a powerful tool for resolving equilibrium structures of neutral metal and semiconductor clusters. Herein, we present electric molecular beam deflection experiments on PbN (N = 7-18) clusters. Promising structures are generated using the unbiased Birmingham Cluster Genetic Algorithm approach based on density functional theory. The structures are further relaxed within the framework of two-component density functional theory taking scalar relativistic and spin orbit effects into account. Quantum chemical results are used to model electric molecular beam deflection profiles based on molecular dynamics calculations. Comparison of measured and simulated beam profiles allows the assignment of equilibrium structures for the most cluster sizes in the examined range for the first time. Neutral lead clusters adopt mainly spherical geometries and resemble the structures of lead cluster cations apart from Pb10. Their growth pattern deviates strongly from the one observed for tin and germanium clusters.
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627Götz, D. A.; Shayeghi, A.; Johnston, R. L.; Schwerdtfeger, P.; Schäfer, R. Structural evolution and metallicity of lead clusters. Nanoscale 2016, 8, 11153– 11160, DOI: 10.1039/C6NR02080AGoogle Scholar627https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28bpvFGqtA%253D%253D&md5=c662b1708b39c56133472b720d7f35c2Structural evolution and metallicity of lead clustersGotz Daniel A; Shayeghi Armin; Johnston Roy L; Schwerdtfeger Peter; Schafer RolfNanoscale (2016), 8 (21), 11153-60 ISSN:.The evolution of the metallic state in lead clusters and its structural implications are subject to ongoing discussions. Here we present molecular beam electric deflection studies of neutral PbN (N = 19-25, 31, 36, 54) clusters. Many of them exhibit dipole moments or anomalies of the polarizability indicating a non-metallic state. In order to resolve their structures, the configurational space is searched using the Pool Birmingham Cluster Genetic algorithm based on density functional theory. Spin-orbit effects on the geometries and dipole moments are taken into account by further relaxing them with two-component density functional theory. Geometries and dielectric properties from quantum chemical calculations are then used to simulate beam deflection profiles. Structures are assigned by the comparison of measured and simulated beam profiles. Energy gaps are calculated using time-dependent density functional theory. They are compared to Kubo gaps, which are an indicator of the metallicity in finite particles. Both, experimental and theoretical data suggest that lead clusters are not metallic up to at least 36 atoms.
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628Wang, B.; Zhao, J.; Chen, X.; Shi, D.; Wang, G. Atomic structures and covalent-to-metallic transition of lead clusters Pbn (n = 2–22). Phys. Rev. A: At., Mol., Opt. Phys. 2005, 71, 033201, DOI: 10.1103/PhysRevA.71.033201Google Scholar628https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjsFGmur8%253D&md5=60a1376bf378419738324370c5f2bd92Atomic structures and covalent-to-metallic transition of lead clusters Pbn (n=2-22)Wang, Baolin; Zhao, Jijun; Chen, Xiaoshuang; Shi, Daning; Wang, GuanghouPhysical Review A: Atomic, Molecular, and Optical Physics (2005), 71 (3-B), 033201/1-033201/7CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)The lowest-energy structures and electronic properties of the lead clusters are studied by d.-functional-theory calcns. with Becke-Lee-Yang-Parr gradient correction. The lowest-energy structures of Pbn (n = 2-22) clusters are detd. from a no. of structural isomers, which are generated from empirical genetic algorithm simulations. The competition between atom-centered compact structures and layered stacking structures leads to the alternative appearance of the two types of structures as global min. The size evolution of geometric and electronic properties from covalent bonding towards bulk metallic behavior in Pb clusters is discussed.
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629Cui, L.-F.; Huang, X.; Wang, L.-M.; Li, J.; Wang, L.-S. J. Phys. Chem. A 2006, 110, 10169– 10172, DOI: 10.1021/jp063617xGoogle Scholar629https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XnsFemt7o%253D&md5=bfb1655a111df852d00cbfff45f078a8Pb122-: PlumbasphereneCui, Li-Feng; Huang, Xin; Wang, Lei-Ming; Li, Jun; Wang, Lai-ShengJournal of Physical Chemistry A (2006), 110 (34), 10169-10172CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Although Si or Ge are not known to form empty cage clusters such as the fullerenes, we recently found a unique 12-atom icosahedral tin cluster, Sn122- (stannaspherene). Here we report photoelectron spectroscopy and theor. evidence that Pb122- is also a highly stable icosahedral cage cluster and bonded by four delocalized radial π bonds and nine delocalized on-sphere σ bonds from the 6p orbitals of the Pb atoms. Following Sn122-, we coin a name, plumbaspherene, for the highly stable and nearly spherical Pb122- cluster, which is expected to be stable in soln. and the solid state. Plumbaspherene has a diam. of ∼6.3 Å with an empty interior vol. large enough to host most transition metal atoms, affording a new class of endohedral clusters.
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630Zhang, X.; Li, G.; Xing, X.; Zhao, X.; Tang, Z.; Gao, Z. Formation of binary alloy cluster ions from group-14 elements and cobalt and comparison with solid-state alloys. Rapid Commun. Mass Spectrom. 2001, 15, 2399– 2403, DOI: 10.1002/rcm.530Google Scholar630https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjtVKhtg%253D%253D&md5=97527381ef4b7386a1e9aa2da6056b82Formation of binary alloy cluster ions from group-14 elements and cobalt and comparison with solid-state alloysZhang, Xia; Li, Guoliang; Xing, Xiaopeng; Zhao, Xiang; Tang, Zichao; Gao, ZhenRapid Communications in Mass Spectrometry (2001), 15 (24), 2399-2403CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)By using laser ablation on mixts. of transition metal Co and group-14 elements, binary alloy cluster anions were produced while no binary alloy cluster cations were detected, and the homo-cluster cations of group-14 elements appeared at very low abundance. The differences between clustering abilities of Ge, Sn and lead with Co are described, and the chem. bonds in the binary alloy cluster anions appear to indicate a transition from covalent to metal bonds. The cluster anion [CoPb10]- appears in very high abundance (magic no.), and an endohedral structure is proposed for this cluster. The cluster anion [CoPb12]-, also representing a magic no., probably has an icosahedral structure. Compared with solid-state Co/Ge binary alloys, the compns. of most binary alloy cluster anions are Ge-rich, in which the covalent bonds are predominant.
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631Xing, X.; Tian, Z.; Liu, H.; Tang, Z. Magic bimetallic cluster anions of M/Pb (M = Au, Ag and Cu) observed and analyzed by laser ablation and time-of-flight mass spectrometry. Rapid Commun. Mass Spectrom. 2003, 17, 1411– 1415, DOI: 10.1002/rcm.1063Google Scholar631https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXltFejtbg%253D&md5=2ab4e406be173e20eb329f5e624a792cMagic bimetallic cluster anions of M/Pb (M = Au, Ag and Cu) observed and analyzed by laser ablation and time-of-flight mass spectrometryXing, Xiaopeng; Tian, Zhixin; Liu, Hongtao; Tang, ZichaoRapid Communications in Mass Spectrometry (2003), 17 (13), 1411-1415CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)By using laser ablation on mixts. of coinage metals M (Cu, Ag, Au) and lead, M/Pb binary cluster anions contg. up to tens of atoms were produced and analyzed. Most of the magic clusters discovered can be described based on the electron shell models which were deduced from simple homogeneous metal cluster systems. The clustering activities of coinage metals and lead were also compared with the properties of their bulk binary alloys.
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632Schäfer, S.; Schäfer, R. New molecular cage clusters of Pb by encapsulation of Mg. ChemPhysChem 2008, 9, 1925– 1929, DOI: 10.1002/cphc.200800264Google Scholar632https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1cngsVGqtg%253D%253D&md5=35bc5b8232a18ba3551dc771f3201e49New molecular cage clusters of Pb by encapsulation of MgSchafer Sascha; Schafer RolfChemphyschem : a European journal of chemical physics and physical chemistry (2008), 9 (13), 1925-9 ISSN:.Endohedral clusters formed from the Zintl ions Pb(10) (2-) and Pb(12) (2-) are particularly stable and therefore suitable for the assembly of larger aggregates. We therefore investigate the formation of Mg-doped lead clusters in the gas phase, and demonstrate that a whole series of new molecular cage clusters of lead can be generated by encapsulation of magnesium. Mass spectrometry reveals that some of the cluster compounds, with one and two Mg atoms attached to the lead clusters, display large intensities compared to the pure lead clusters, which indicates that the compound clusters are particularly stable. The magnesium-doped lead-cluster assemblies were further analyzed within a molecular-beam electric deflection experiment. Almost vanishing permanent dipole moments for MgPb(10-16) support the idea that a single Mg atom could be encapsulated within a highly symmetric lead cage, which results in structures with not only enhanced stability but also increased symmetry compared to the pure lead clusters Pb(N).
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633Grubisic, A.; Wang, H.; Li, X.; Ko, Y.-J.; Kocak, F. S.; Pederson, M. R.; Bowen, K. H.; Eichhorn, B. W. Photoelectron spectroscopic and computational studies of the Pt@Pd10- and Pt@Pd121-/2- anions. Proc. Natl. Acad. Sci. U. S. A. 2011, 108, 14757– 14762, DOI: 10.1073/pnas.1105052108Google Scholar633https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFyktLnF&md5=241bb599d8f017fb7edf3cc5ce4aa82cPhotoelectron spectroscopic and computational studies of the Pt@Pb101- and Pt@Pb121-/2- anionsGrubisic, Andrej; Wang, Haopeng; Li, Xiang; Ko, Yeon-Jae; Kocak, F. Sanem; Pederson, Mark R.; Bowena, Kit H.; Eichhorn, Bryan W.Proceedings of the National Academy of Sciences of the United States of America (2011), 108 (36), 14757-14762, S14757/1-S14757/2CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)A combination of anion photoelectron spectroscopy and d. functional theory calcns. has elucidated the geometric and electronic structure of gas-phase endohedral Pt/Pb cage cluster anions. The anions, Pt@Pb101- and Pt@Pb121- were prepd. from "preassembled" clusters generated from cryst. samples of [K(2,2,2-crypt)]2[Pt@Pb12] that were brought into the gas phase using a unique IR desorption/photoemission anion source. The use of cryst. [K(2,2,2-crypt)]2[Pt@Pb12] also provided access to K[Pt@Pbn]- anions in the gas phase (i.e., the K+ salts of the Pt@Pbn2- anions). Anion photoelectron spectra of Pt@Pb101-, Pt@Pb121-, and K[Pt@Pb12]1- are presented. Extensive d. functional theory calcns. on Pt@Pb103-/2-/1-/0 and Pt@Pb122-/1- provided candidate structures and anion photoelectron spectra for Pt@Pb101- and Pt@Pb121-. Together, the calcd. and measured photoelectron spectra show that Pt@Pb101- and Pt@Pb121- endohedral complexes maintain their resp. D4d and slightly distorted Ih symmetries in the gas phase even for the charge states with open shell character. Aside from the fullerenes, the Pt@Pb122- endohedral complex is the only bare cluster that has been structurally characterized in the solid state, soln., and the gas phase.
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634Bhattacharyya, S.; Nguyen, T. T.; De Haeck, J.; Hansen, K.; Lievens, P.; Janssens, E. Mass-selected photodissociation studies of AlPbn+ clusters (n = 7–16): Evidence for the extraordinary stability of AlPb10+ and AlPb12+. Phys. Rev. B: Condens. Matter Mater. Phys. 2013, 87, 054103, DOI: 10.1103/PhysRevB.87.054103Google Scholar634https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltlGktb8%253D&md5=06e42fd40ea888721b63c9dbd1e0494fMass-selected photodissociation studies of AlPbn+ clusters (n = 7-16): evidence for the extraordinary stability of AlPb10+ and AlPb12+Bhattacharyya, Soumen; Nguyen, Thanh Tung; De Haeck, Jorg; Hansen, Klavs; Lievens, Peter; Janssens, EwaldPhysical Review B: Condensed Matter and Materials Physics (2013), 87 (5), 054103/1-054103/7CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors report fragmentation pathways and dissocn. energies of AlPbn+ (n = 7-16) clusters. The clusters are produced with pulsed laser vaporization and studied in a supersonic mol. beam setup. They are mass selected and photodissociated with 532 and 355 nm laser light. Photofragments are thereafter mass sepd. in a tandem reflectron time-of-flight mass spectrometer. Bare Pbn+ (n = 8-16) clusters preferentially evap. Pb atoms, with the exception of Pb15+ that fragments by loss of a Pb2 dimer to form the stable Pb13+ cluster. The smallest AlPbn+ (n = 7-11) clusters also show mainly at. Pb evapn., whereas the favored fragmentation pathway of the larger clusters (n = 12-16) involves Pb2 and Pb3 fragments. AlPb10+ and AlPb12+ are the most intense fragments of several larger cluster sizes, demonstrating the high stability of these two sizes. Dissocn. energies corresponding to the most facile fragmentation channel of AlPbn+ (n = 11-15) are bracketed from the measured laser fluence dependencies of the fragment intensities using constraints imposed by unimol. reaction rates.
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635Xie, H.; Qin, Z.; Wu, X.; Tang, Z.; Jiang, L. Photoelectron velocity-map imaging signature of structural evolution of silver-doped lead Zintl anions. J. Chem. Phys. 2012, 137, 064318, DOI: 10.1063/1.4745000Google Scholar635https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFOrsbfP&md5=c773971bf8d7102040ed6ac0f2061a84Photoelectron velocity-map imaging signature of structural evolution of silver-doped lead Zintl anionsXie, Hua; Qin, Zhengbo; Wu, Xia; Tang, Zichao; Jiang, LingJournal of Chemical Physics (2012), 137 (6), 064318/1-064318/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A set of silver-doped lead Zintl anions, Ag@Pbn- (n = 5-12), have been studied using photoelectron velocity-map imaging spectroscopy and quantum chem. calcn. The structures of Ag@Pbn- (n = 7-9, 11) built upon a square pyramid base, hitherto not considered, were assigned. Overall agreement between the exptl. and calcd. photoelectron spectra as well as vertical detachment energies allows for structural evolution to be established. The silver atom prefers to stay outside in the n ≤ 6 clusters and intends to be encapsulated by the lead atoms in n > 6. A stable endohedral cage with bicapped square antiprism structure is formed at n = 10, the endohedral structure of which persists for the larger clusters. Esp., these Ag@Pbn- anions have been found to undergo a transition between square pyramid and pentagonal pyramid mol. structures at n = 11. (c) 2012 American Institute of Physics.
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636Rajesh, C.; Majumder, C. Structure and electronic properties of PbnM (M = C, Al, In, Mg, Sr, Ba, and Pb; n = 8, 10, 12, and 14) clusters: Theoretical investigations based on first principles calculations. J. Chem. Phys. 2008, 128, 024308, DOI: 10.1063/1.2814166Google Scholar636https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosVOjtg%253D%253D&md5=283dda4862536087a25c9ea16c4f4df7Structure and electronic properties of PbnM (M = C, Al, In, Mg, Sr, Ba, and Pb; n = 8, 10, 12, and 14) clusters: Theoretical investigations based on first principles calculationsRajesh, Chinagandham; Majumder, ChiranjibJournal of Chemical Physics (2008), 128 (2), 024308/1-024308/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A systematic theor. study of the PbnM (M=C, Al, In, Mg, Sr, Ba, and Pb; n=8, 10, 12, and 14) clusters have been investigated to explore the effect of impurity atoms on the structure and electronic properties of lead clusters. The calcns. were carried out using the d. functional theory with generalized gradient approxn. for exchange-correlation potential. Extensive search based on large nos. of initial configurations has been carried out to locate the stable isomers of PbnM clusters. The results revealed that the location of the impurity atom depends on the nature of interaction between the impurity atom and the host cluster and the size of the impurity atom. Whereas, the impurity atoms smaller than Pb favor to occupy the endohedral position, the larger atoms form exohedral capping of the host cluster. The stability of these clusters has been analyzed based on the av. binding energy, interaction energy of the impurity atoms, and the energy gap between the highest occupied and lowest unoccupied energy levels (HLG). Based on the energetics, it is found that p-p interaction dominates over the s-p interaction and smaller size atoms interact more strongly. The stability anal. of these clusters suggests that, while the substitution of Pb by C or Al enhances the stability of the Pbn clusters, Mg lowers the stability. Further investigations of the stability of PbnM clusters reveal that the interplay between the at. and electronic structure is crucial to understand the stability of these clusters. The energy gap anal. reveals that, while the substitution of Mg atom widens the HLG, all other elements reduce the gap of the PbnM clusters. (c) 2008 American Institute of Physics.
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637Chen, D.-L.; Tian, W. Q.; Sun, C.-C. First-principles studies of AlPbn and AlPbn+ clusters (n = 1–12): Search for Al-doped clusters with large stabilities. Phys. Rev. A: At., Mol., Opt. Phys. 2007, 75, 013201, DOI: 10.1103/PhysRevA.75.013201Google Scholar637https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXitlWitbc%253D&md5=7f87d27f5339420a6eab681b99770378First-principles studies of AlPbn and AlPbn+ clusters (n = 1-12): search for Al-doped clusters with large stabilitiesChen, De-Li; Tian, Wei Quan; Sun, Chia-ChungPhysical Review A: Atomic, Molecular, and Optical Physics (2007), 75 (1, Pt. B), 013201/1-013201/8CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)A first-principles d. functional theory based B3LYP (Becke's hybrid three-parameter exchange functional with the LYP correlation functional) method with aug-cc-pVDZ(-PP) [Dunning's augmented correlation consistent valence double zeta with polarization function on Al and pseudopotential for Pb] basis set has been used to search the most stable structures and study the electronic properties of neutral AlPbn and cationic AlPbn+ clusters (n = 1-12). The evolution of energy gaps between the HOMO and the LUMO, binding energies, and vertical ionization potentials of these clusters have been investigated. Several cationic clusters, such as AlPb9+, AlPb10+, and AlPb12+ with enhanced stability have been identified. MO analyses reveal that the special stability of D4d AlPb10+ with 42 valence electrons may arise from the closed-shell nature of the π subsystem, which is subjected to the 2(Nπ+1)2 rule with Nπ = 1. The large nucleus-independent chem. shift (NICS) values indeed demonstrate the high stability of the cationic AlPb10+. Meanwhile, the big cavity and large NICS values of isoelectronic D4d Pb102- suggest that it can encapsulate other appropriate metal atoms successfully. As to the C3v AlPb9+ cluster, its large stability may also arise from the closed-shell nature of the π subsystem with 8 π electrons, further confirmed by the large NICS values. Addnl., the nine-atom Pb clusters Pb92-, Pb93-, and Pb94- possess strong arom. character. Esp., the D3h Pb94- cluster exhibits double spherically arom. character and the largest NICS value at the center of the cage. These pure Pb clusters with large cavities and their encapsulating clusters should be good candidates for making new cluster-assembled nanostructured materials.
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638Chen, X.; Deng, K.; Xiao, C.; Chen, J.; Ellis, D. E. Geometric and magnetic properties of the neutral MPb10 and [MPb10]2 clusters (M = Fe, Co, Ni). Comput. Theor. Chem. 2011, 971, 73– 76, DOI: 10.1016/j.comptc.2011.06.008Google Scholar638https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVKgsrvL&md5=b89622dcf91234058dd77246538ab62cGeometric and magnetic properties of the neutral MPb10 and [MPb10]2 clusters (M = Fe, Co, Ni)Chen, Xuan; Deng, Kaiming; Xiao, Chuanyun; Chen, Jiuhua; Ellis, D. E.Computational & Theoretical Chemistry (2011), 971 (1-3), 73-76CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The geometric properties of the MPb10 monomers and their dimers (M = Fe, Co, Ni) are studied using the d.-functional method. A lot of geometries of MPb10 have been searched. We found that the transition metal (M = Fe, Co, Ni) atom is favorable to be encapsulated into the Pb10 cage, and the structure of MPb10 with an encapsulated square antiprism is energetically favorable. Furthermore, these monomers could be assembled stable dimers and retain their structural identity. The most stable structure of the [MPb10]2 dimer is the two MPb10 monomers to be bound at the triangles facing upside down to each other. In addn., the weak interaction as well as the stability of NiPb10 cluster, suggests that NiPb10 seems better adapted for the purposes of cluster assembling. Meanwhile, the magnetic properties of these monomers and dimers are also investigated.
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639Spiekermann, A.; Hoffmann, S. D.; Fässler, T. F. The Zintl ion [Pb10]2–: A rare example of a homoatomic closo cluster. Angew. Chem., Int. Ed. 2006, 45, 3459– 3462, DOI: 10.1002/anie.200503916Google Scholar639https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlsVKjsLg%253D&md5=3aea6e00a5d01cde4c70ab5eafe9d5ccThe Zintl ion [Pb10]2-: a rare example of a homoatomic closo clusterSpiekermann, Annette; Hoffmann, Stephan D.; Faessler, Thomas F.Angewandte Chemie, International Edition (2006), 45 (21), 3459-3462CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The closed deltahedral homoat. cluster, [Pb10]2-, is prepd. and structurally characterized as its [K(2.2.2-crypt)]+ salt. When this empty cluster is considered together with the recently published filled cluster [Ni@Pb10]2-, a striking parallel to the fullerenes emerges: Zintl ions form polyhedral cages that can enclose a central atom without any major structural alterations.
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640Gao, Y.; Bulusu, S.; Zeng, X. C. A global search of highly stable gold-covered bimetallic clusters M@Aun (n = 8-17) Endohedral gold clusters. ChemPhysChem 2006, 7, 2275– 2278, DOI: 10.1002/cphc.200600472Google Scholar640https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht1OnsrjO&md5=b8902a90c6366e9afaf2d34bb6db1c82A global search of highly stable gold-covered bimetallic clusters M@Aun (n = 8-17): endohedral gold clustersGao, Yi; Bulusu, Satya; Zeng, Xiao ChengChemPhysChem (2006), 7 (11), 2275-2278CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)The lowest-energy structures were calcd. of a series of gold-based bimetallic clusters MAun (n = 8-17), all satisfying the 18-electron rule using DFT. Starting from n = 9, the hetero-metal atom (M) prefers to be entirely covered by gold atoms Aun to attain the lowest-energy structure. W@Au12, Zr@Au14, Sc@Au15, and Y@Au15 are the "magic-no." clusters, having the highest binding energy per atom and the largest HOMO-LUMO gap.
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641Rajesh, C.; Majumder, C. Energy level reordering and stability of MPb12 clusters: An interplay between geometry and electronic structure. Chem. Phys. Lett. 2006, 430, 101– 107, DOI: 10.1016/j.cplett.2006.08.117Google Scholar641https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVWrsrbN&md5=0785c56a5ca8992a01c26e5dcac68275Energy level reordering and stability of MPb12 clusters: An interplay between geometry and electronic structureRajesh, Chinagandham; Majumder, ChiranjibChemical Physics Letters (2006), 430 (1-3), 101-107CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We demonstrate the influence of an impurity atom in tuning the stability of Pb13 cluster. For this purpose we have investigated the electronic and geometric structure of MPb12 (M = Pb, C, Al, Mg) clusters using the ab initio mol. dynamics simulation method. The energy gap between the highest occupied and lowest unoccupied energy levels of Pb13 and MgPb12 is estd. to be 0.95 and 2.3 eV, resp. The significant increase in the energy gap is resulted from the energy level reordering of Pb13 by the incorporation of Mg atom. Further investigations of the stability of MPb12 clusters reveal that the interplay between the at. and electronic structure is crucial to understand the stability of small size clusters.
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642Chen, X.; Deng, K.; Liu, Y.; Tang, C.; Yuan, Y.; Hu, F.; Wu, H.; Huang, D.; Tan, W.; Wang, X. The geometric and magnetic properties of the endohedral plumbaspherene M@Pb12 clusters (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Chem. Phys. Lett. 2008, 462, 275– 279, DOI: 10.1016/j.cplett.2008.07.095Google Scholar642https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGlu77F&md5=d0573e0a18f1e3d46c4bbb0387e6876cThe geometric and magnetic properties of the endohedral plumbaspherene M@Pb12 clusters (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni)Chen, Xuan; Deng, Kaiming; Liu, Yuzhen; Tang, Chunmei; Yuan, Yongbo; Hu, Fenglan; Wu, Haiping; Huang, Decai; Tan, Weishi; Wang, XinChemical Physics Letters (2008), 462 (4-6), 275-279CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometric and magnetic properties of the M@Pb12 clusters (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) are studied using the relativistic d.-functional method. The geometric optimization shows that the ground states of these clusters are close to the Ih structure. The magnetism calcns. demonstrate that the magnetic moments of M@Pb12 vary from 1 μB to 5 μB by doping different transition-metal atoms into Pb12 cage, therefore, they possess tunable magnetic properties and have potential utility in new nanomaterials. The electronic structure calcn. shows that the Mn@Pb12 has large energy gap and doping energy. Furthermore, of particular interesting is that its structure and energy gap remain unchanged with a strong external elec. field up to 0.1 V/Å, thus, Mn@Pb12 would be a good candidate as the building block with high magnetic moment for cluster assembly.
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643Le Guennic, B.; Autschbach, J. [Pt@Pb12]2–—A challenging system for relativistic density functional theory calculations of 195Pt and 207Pb NMR parameters. Can. J. Chem. 2011, 89, 814– 821, DOI: 10.1139/v11-054Google Scholar643https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXosl2ksbw%253D&md5=0e36cbedfa226b2ef8d604b67c74eb49[Pt@Pb12]2- - A challenging system for relativistic density functional theory calculations of 195Pt and 207Pb NMR parametersLe Guennic, Boris; Autschbach, JochenCanadian Journal of Chemistry (2011), 89 (7), 814-821CODEN: CJCHAG; ISSN:0008-4042. (Canadian Science Publishing)The authors report computations of NMR chem. shifts and indirect spin-spin coupling consts. (J couplings) for the [Pt@Pb12]2- superatom. The system is strongly influenced by relativistic effects. The Pt-Pb coupling const. is predicted to be neg., with its magnitude being in reasonable agreement with expt. Pt and Pb chem. shifts also agree reasonably well with expt. The Pb shielding tensor is strongly anisotropic, with a large deshielding principal component dominated by magnetic coupling between frontier orbitals of the cluster that resemble at. g orbitals. The NMR parameters are sensitive to approxns. made in the computations and require the inclusion of spin-orbit coupling in the theor. model to achieve reliable results. Computing the NMR parameters of the compact [Pt@Pb12]2- system with its many electrons proves to be a challenging test case for relativistic d. functional methods.
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644Chen, D.-L.; Tian, W. Q.; Lu, W.-C.; Sun, C.-C. Special stability of cationic MPb12+ clusters and superalkali character of neutral MPb12 clusters (M = B, Al, Ga, In, and Tl). J. Chem. Phys. 2006, 124, 154313, DOI: 10.1063/1.2189224Google Scholar644https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjvF2nu7o%253D&md5=40bcea38cc46e94ccef9a7e6e85ea1deSpecial stability of cationic MPb12+ clusters and superalkali character of neutral MPb12 clusters (M=B, Al, Ga, In, and Tl)Chen, De-Li; Tian, Wei Quan; Lu, Wen-Cai; Sun, Chia-ChungJournal of Chemical Physics (2006), 124 (15), 154313/1-154313/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic structures and stabilities of cationic MPb12+ clusters (M = B, Al, Ga, In, and Tl) with 50 valence electrons are investigated within d. functional theory. It is shown that, at the B3LYP/cc-pVDZ(-PP) and BPW91/cc-pVDZ(-PP) levels of theory, the structures of MPb12+ with icosahedra (Ih) symmetry are energetically favorable, and their high stabilities may arise from the closed-shell nature of the π subsystems which are subject to the 2(Nπ + 1)2 rule with Nπ = 1. In addn., the possessing of large nucleus-independent chem. shifts of the five kinds of clusters reflects the common arom. character of these clusters. From the comparison of our studies on the binding energies and the HOMO and the LUMO energy gaps, the cluster AlPb12+ has higher stability than the others and this is consistent with the recent mass-spectrometric discovery of Al-doped Pb+n clusters, in which AlPb+12 is highly abundant. The same methods are used to search for the structures of the neutral MPb12 clusters. The calcns. reveal that the most stable geometries of the BPb12 and GaPb12 clusters have Ih symmetry, the AlPb12 and InPb12 clusters have Th symmetry, and the TlPb12 cluster has C5v symmetry. Furthermore, the vertical ionization potentials of the neutral MPb12 clusters are smaller than that of some alkali atoms, indicating that the neutral MPb12 clusters possess superalkali character.
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645Witzel, B. J.; Klein, W.; Dums, J. V.; Boyko, M.; Fässler, T. F. Metallocages for metal anions: Highly charged [Co@Ge9]5– and [Ru@Sn9]6– clusters featuring spherically encapsulated Co1– and Ru2– anions. Angew. Chem., Int. Ed. 2019, 58, 12908– 12913, DOI: 10.1002/anie.201907127Google Scholar645https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1ait7vE&md5=d8f0c9792967ffecccaba7e64025bf4bMetallocages for Metal Anions: Highly Charged [Co@Ge9]5- and [Ru@Sn9]6- Clusters Featuring Spherically Encapsulated Co1- and Ru2- AnionsWitzel, Benedikt J. L.; Klein, Wilhelm; Dums, Jasmin V.; Boyko, Marina; Faessler, Thomas F.Angewandte Chemie, International Edition (2019), 58 (37), 12908-12913CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Endohedral clusters count as mol. models for intermetallic compds.-a class of compds. in which bonding principles are scarcely understood. Herein we report sol. cluster anions with the highest charges on a single cluster to date. The clusters reflect the close analogy between intermetalloid clusters and corresponding coordination polyhedra in intermetallic compds. We now establish Raman spectroscopy as a reliable probe to assign for the first time the presence of discrete, endohedrally filled clusters in intermetallic phases. The ternary precursor alloys with nominal compns. "K5Co1.2Ge9" and "K4Ru3Sn7" exhibit characteristic bonding modes originating from metal atoms in the center of polyhedral clusters, thus revealing that filled clusters are present in these alloys. We report also on the structural characterization of [Co@Ge9]5- (1a) and [Ru@Sn9]6- (2a) obtained from solns. of the resp. alloys.
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646Yue, C. Y.; Wang, M. F.; Yuan, Z. D.; Zhou, F. X.; Zhang, H. P.; Lei, X. W. K13CoSn17–x (x = 0.1): A new ternary phase containing cobalt centered [Sn9] cluster synthesized via high-temperature reaction. Z. Anorg. Allg. Chem. 2013, 639, 911– 917, DOI: 10.1002/zaac.201300181Google Scholar646https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnsFSrsrs%253D&md5=2c63bc558673f340396c7c0e1c242e43K13CoSn17-x (x = 0.1). A new ternary phase containing cobalt centered [Sn9] cluster synthesized via high-temperature reactionYue, Cheng-Yang; Wang, Ming-Feng; Yuan, Zhuang-Dong; Zhou, Fang-Xia; Zhang, Hui-Ping; Lei, Xiao-WuZeitschrift fuer Anorganische und Allgemeine Chemie (2013), 639 (6), 911-917CODEN: ZAACAB; ISSN:0044-2313. (Wiley-VCH Verlag GmbH & Co. KGaA)A new ternary potassium cobalt stannide, K13CoSn17-x (x = 0.1), was obtained by reacting the mixt. of the corresponding pure elements at high temp., and structurally characterized by single-crystal x-ray diffraction study. K13CoSn17-x (x = 0.1) crystallizes in the orthorhombic space group Pbca with a 26.2799(7), b 24.1541(6), c 29.8839(6) Å, Z = 16, 18,168 obsd. reflections with I > 2σ(I), R1 = 0.0540, wR2 = 0.1243. its structure contains isolated [CoSn9] monocapped square antiprism and [Sn4] tetrahedron in the ratio 1:2, forming a hierarchical variant of Laves phase MgZn2. the structural relation between the title compd. with MgZn2 as well as other binary stannides is also discussed.
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647Rios, D.; Gillett-Kunnath, M. M.; Taylor, J. D.; Oliver, A. G.; Sevov, S. C. Addition of a thallium vertex to empty and centered nine-atom deltahedral zintl ions of germanium and tin. Inorg. Chem. 2011, 50, 2373– 2377, DOI: 10.1021/ic102152eGoogle Scholar647https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFamsrY%253D&md5=654fc2223fe6d1e19394248a80208062Addition of a thallium vertex to empty and centered nine-atom deltahedral Zintl ions of germanium and tinRios, Daniel; Gillett-Kunnath, Miriam M.; Taylor, Jacob D.; Oliver, Allen G.; Sevov, Slavi C.Inorganic Chemistry (2011), 50 (6), 2373-2377CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Ni atoms were inserted into nine-atom deltahedral Zintl ions of E94- (E = Ge, Sn) via reactions with Ni(cod)2 (cod = cyclooctadiene), and [Ni@Sn9]3- was structurally characterized. Both the empty and the Ni-centered clusters react with TlCp (Cp = cyclopentadienyl anion) and add a Tl vertex to form the deltahedral ten-atom closo-species [E9Tl]3- and [Ni@E9Tl]3-, resp. The structures of [Ge9Tl]3- and [Ni@Sn9Tl]3- showed that, as expected, the geometry of the ten-atom clusters is that of a bicapped square antiprism where the Tl-atom occupies one of the two capping vertexes. This illustrates that centering a nine-atom cluster with a Ni atom does not change its reactivity toward TlCp. All compds. were characterized by electrospray mass spectrometry.
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648Gillett-Kunnath, M. M.; Paik, J. I.; Jensen, S. M.; Taylor, J. D.; Sevov, S. C. Metal-centered deltahedral zintl ions: Synthesis of [Ni@Sn9]4– by direct extraction from intermetallic precursors and of the vertex-fused dimer [{Ni@Sn8(μ-Ge)1/2}2]4–. Inorg. Chem. 2011, 50, 11695– 11701, DOI: 10.1021/ic2016963Google Scholar648https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlKksb7I&md5=5966071b03d387be4d224c68cd24a0beMetal-Centered Deltahedral Zintl Ions: Synthesis of [Ni@Sn9]4- by Direct Extraction from Intermetallic Precursors and of the Vertex-Fused Dimer [{Ni@Sn8(μ-Ge)1/2}2]4-Gillett-Kunnath, Miriam M.; Paik, Joseph I.; Jensen, Sara M.; Taylor, Jacob D.; Sevov, Slavi C.Inorganic Chemistry (2011), 50 (22), 11695-11701CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Ni-centered deltahedral Sn9 clusters with a charge of 4-, i.e., [Ni@Sn9]4-, were extd. in ethylenediamine in high yield directly from intermetallic precursors with the nominal compn. K4Sn9Ni3. The new endohedral clusters were crystd. and structurally characterized in K[K(18-crown-6)]3[Ni@Sn9]·3 benzene (1a, triclinic, space group P‾1, a 10.2754(5), b 19.5442(9), and c 20.5576(13) Å, α 73.927(3), β 79.838(4), and γ 84.389(3)°, Z = 2) and K[K(2,2,2-crypt)]3[Ni@Sn9] (1b, triclinic, space group P‾1, a 15.8028(8), b 16.21350(9), and c 20.1760(12) Å, α 98.71040(10), β 104.4690(10), and γ 118.3890(10)°, Z = 2). The alternative method of a post-synthetic insertion of a Ni atom in empty Sn9 clusters by a reaction with Ni(cod)2 predominantly produces the more-oxidized clusters with a charge of 3-, i.e., the recently reported [Ni@Sn9]3-. Nonetheless, using substoichiometric amts. of 18-crown-6 as a cation sequestering agent, the authors also were able to isolate the 4- clusters as a minor phase from such reactions. They were structurally characterized in K[K(en)][K(18-crown-6)]2[Ni@Sn9]·0.5en (2, monoclinic, space group P21/n, a 10.4153(5), b 25.6788(11), and c 20.6630(9) Å, β 102.530(2)°, Z = 2). The ability of the Ni-centered clusters to exist with both 3- and 4- charges parallels the same ability of the empty clusters and is very promising for similarly rich chem. involving electron transfer and flexible oxidn. states. The authors also report the synthesis and characterization of the endohedral heteroat. dimer [{Ni@Sn8(μ-Ge)1/2}2]4- composed of two [Ni@(Sn8Ge)]-clusters fused at the Ge-vertex. The dimer was synthesized by reacting an ethylenediamine soln. of a ternary precursor with the nominal compn. K4Ge4.5Sn4.5, which is known to produce heteroat. Ge9-xSnx clusters, with Ni(cod)2. It is isostructural with the reported [{Ni@Sn8(μ-Sn)1/2}2]4- and is structurally characterized in [K-(2,2,2-crypt)]4[{Ni@Sn8(μ-Ge)1/2}2]·2en (3, monoclinic, space group C2/c, a 30.636(2), b 16.5548(12), and c 28.872(2) Å, β 121.2140(10)°, Z = 4).
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649Benda, C. B.; Waibel, M.; Köchner, T.; Fässler, T. F. Reactivity of liquid ammonia solutions of the zintl phase K12Sn17 towards mesitylcopper (I) and phosphinegold (I) chloride. Chem. - Eur. J. 2014, 20, 16738– 16746, DOI: 10.1002/chem.201404594Google Scholar649https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVCiurfO&md5=1cb14830557bcca8f971742c76edaa00Reactivity of Liquid Ammonia Solutions of the Zintl Phase K12Sn17 towards Mesitylcopper(I) and Phosphinegold(I) ChlorideBenda, Christian B.; Waibel, Markus; Koechner, Tobias; Faessler, Thomas F.Chemistry - A European Journal (2014), 20 (50), 16738-16746CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)To gain more insight into the reactivity of intermetalloid clusters, the reactivity of the Zintl phase K12Sn17, which contains [Sn4]4- and [Sn9]4- cluster anions, was investigated. The reaction of K12Sn17 with gold(I) phosphine chloride yielded K7[(η2-Sn4)Au(η2-Sn4)](NH3)16 (1) and K17[(η2-Sn4)Au(η2-Sn4)]2(NH2)3(NH3)52 (2), which both contain the anion [(Sn4)Au(Sn4)]7- (1a) that consists of two [Sn4]4- tetrahedra linked through a central gold atom. Anion 1a represents the first binary Au-Sn polyanion. From this reaction, the solvate structure [K([2.2.2]crypt)]3K[Sn9](NH3)18 (3; [2.2.2]crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) was also obtained. In the analogous reaction of mesitylcopper with K12Sn17 in the presence of [18]crown-6 in liq. ammonia, crystals of the compn. [K([18]crown-6)]2[K([18]crown-6)(MesH)(NH3)][Cu@Sn9](THF) (4) were isolated ([18]crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadiene, MesH = mesitylene, THF = tetrahydrofuran) and featured a [Cu@Sn9]3- cluster. A similar reaction with [2.2.2]crypt as a sequestering agent gave crystals of [K[2.2.2]crypt][MesCuMes] (5). The cocrystn. of mesitylene in 4 and the presence of [MesCuMes]- (5a) in 5 provides strong evidence that the migration of a bare Cu atom into an Sn9 anion takes place through the release of a Mes- anion from mesitylcopper, which either migrates to another mesitylcopper to form 5a or is subsequently protonated to give MesH.
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650Esenturk, E. N.; Fettinger, J.; Eichhorn, B. The closo-Pb102– Zintl ion in the [Ni@Pb10]2– cluster. Chem. Commun. 2005, 247– 249, DOI: 10.1039/b412082eGoogle Scholar650https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjtFGgsw%253D%253D&md5=aef4a91e246f74e302926909e7998c9aThe closo-Pb102- Zintl ion in the [Ni@Pb10]2- clusterEsenturk, Emren N.; Fettinger, James; Eichhorn, BryanChemical Communications (Cambridge, United Kingdom) (2005), (2), 247-249CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The cluster [Ni@Pb10]2-, prepd. from Pb94- and Ni(COD)2, contains a new Zintl ion subunit, closo-Pb102-, centered by a Ni atom. [K(2,2,2-crypt)]2[Ni@Pb10] is monoclinic, space group C2/c, R1 = 0.0582, wR2 = 0.1645.
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651Esenturk, E. N.; Fettinger, J.; Eichhorn, B. The Pb122- and Pb102- zintl ions and the M@Pb122– and M@Pb102– cluster series where M = Ni, Pd, Pt. J. Am. Chem. Soc. 2006, 128, 9178– 9186, DOI: 10.1021/ja061842mGoogle Scholar651https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xmt12muro%253D&md5=55f19bd641f53cd65c6ecaa506d34004The Pb122- and Pb102- Zintl Ions and the M@Pb122- and M@Pb102- Cluster Series Where M = Ni, Pd, PtEsenturk, Emren N.; Fettinger, James; Eichhorn, BryanJournal of the American Chemical Society (2006), 128 (28), 9178-9186CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Ethylenediamine (en) solns. of K4Pb9 react with toluene solns. of ML4 (M = Pt, Pd, L = PPh3; M = Ni, L2 = COD) and 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (2,2,2-crypt) to give M@Pb122- cluster anions (M = Pt, Pd, Ni) as the [K(2,2,2-crypt)]+ salts in low (Ni) to good (Pt) yields. The ions have near perfect Ih point symmetry and have been characterized by X-ray diffraction, 207Pb NMR and LDI-TOF mass spectrometry studies. For M = Ni, the primary product formed is the D4d Ni@Pb102- cluster that has also been structurally characterized. The M@Pb102- clusters (M = Pd, Pt) and the new Zintl ions closo-Pb102- and closo-Pb122- were formed in the gas phase but have not been detected in soln. or the solid state. The structural trends of these series of clusters have been investigated through DFT calcns. The Ni@Pb102- cluster is dynamic on the 207Pb NMR time scale at -45 °C and 104.7 MHz. The M@Pb122- ions show unusually deshielded 207Pb NMR chem. shifts that presumably arise from σ-arom. effects assocd. with their high symmetries. In the solid state the salts form superlattices of cations and anions (e.g. the AlB2 lattice of [K(2,2,2-crypt)]2[Pt@Pb12]) and are prototypes for "assembled cluster materials".
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652Krämer, T.; Duckworth, J. C.; Ingram, M. D.; Zhou, B.; McGrady, J. E.; Goicoechea, J. M. Structural trends in ten-vertex endohedral clusters, M@E10 and the synthesis of a new member of the family, [Fe@Sn10]3–. Dalton Trans. 2013, 42, 12120– 12129, DOI: 10.1039/c3dt50643fGoogle Scholar652https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3srptlKqsg%253D%253D&md5=c56a5a4453833a663cc4c3d64ed6f6b0Structural trends in ten-vertex endohedral clusters, M@E(10) and the synthesis of a new member of the family, [Fe@Sn10]3-Kramer Tobias; Duckworth Jack C A; Ingram Matthew D; Zhou Binbin; McGrady John E; Goicoechea Jose MDalton transactions (Cambridge, England : 2003) (2013), 42 (34), 12120-9 ISSN:.The synthesis of a new endohedral ten-vertex Zintl ion cluster, [Fe@Sn10](3-), isoelectronic with [Fe@Ge10](3-), is reported. In an attempt to place this new cluster within the context of the known structural chemistry of the M@E10 family (M = transition metal, E = main group element), we have carried out a detailed electronic structure analysis of the different structural types: viz bicapped square antiprismatic ([Ni@Pb10](2-), [Zn@In10](8-)), tetra-capped trigonal prismatic ([Ni@In10](10-)) and the remarkable pentagonal prismatic [Fe@Ge10](3-) and [Co@Ge10](3-). We establish that the structural trends can be interpreted in terms of a continuum of effective electron counts at the E10 cage, ranging from electron deficient (<4n + 2) in [Ni@In10](10-) to highly electron rich (>4n + 2) in [Fe@Ge10](3-). The effective electron count differs from the total valence electron count in that it factors in the increasingly active role of the metal d electrons towards the left of the transition series. The preference for a pentagonal prismatic geometry in [Fe@Ge10](3-) emerges as a natural consequence of backbonding to the cage from four orthogonal 3d orbitals of the low-valent metal ion. Our calculations suggest that the new [Fe@Sn10](3-) cluster should also exhibit structural consequences of backbonding from the metal to the cage, albeit to a less extreme degree than in its Ge analogue. The global minimum lies on a very flat surface connecting D4d, C2v and C3v-symmetric minima, suggesting a very plastic structure that may be easily deformed by the surrounding crystal environment. If so, then this provides a new and quite distinct structural type for the M@E10 family.
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653Esenturk, E. N.; Fettinger, J.; Lam, Y. F.; Eichhorn, B. [Pt@Pb12]2–. Angew. Chem., Int. Ed. 2004, 43, 2132– 2134, DOI: 10.1002/anie.200353287Google Scholar653https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjsFSjsbk%253D&md5=241e54ed1d0c983af0206e7e30879b49[Pt@Pb12]2-Esenturk, Emren N.; Fettinger, James; Lam, Yiu-Fai; Eichhorn, BryanAngewandte Chemie, International Edition (2004), 43 (16), 2132-2134CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The Pt centered [Pb12]2- icosahedron was prepd. from the [Pb9]4- Zintl ion and [Pt(PPh3)4] in good yield. The anion has virtual Ih point symmetry and is a rare example of a free-standing C-free arom. inorg. cluster.
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654Wang, Y.; Wang, L.-L.; Ruan, H.-P.; Luo, B.-L.; Sang, R.-L.; Xu, L. Synthesis and characterization of the endohedral plumbaspherene [Rh@Pb12]3-. Chin. J. Struct. Chem. 2015, 34, 1253– 1258Google Scholar654https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVSmurfN&md5=905527c6bb9adfc34dbf89e3d59a56b8Synthesis and characterization of endohedral plumbaspherene [Rh@Pb12]3-Wang, Yi; Wang, Lu-lu; Ruan, Hua-peng; Luo, Ben-long; Sang, Rui-li; Xu, LiChinese Journal of Structural Chemistry (2015), 34 (8), 1253-1258CODEN: CJSCBE ISSN:. (Editorial Board of Chinese Journal of Structural Chemistry)The endohedral plumbaspherene cluster anion [Rh@Pb12]3- was synthesized by the reaction of K4Pb9 with Rh(PPh3)3Cl in ethylenediamine (en) soln. in the presence of 18-crown-6(1,4,7,10,13,16-hexaoxacyclooctadecane), and characterized by single-crystal x-ray diffraction and energy-dispersive X-ray (EDX) anal. The novel zintl ion cluster [Rh@Pb12]3- represents the 1st structurally characterized plumbaspherene Pb12 cluster with Ih point symmetry encapsulating a Group 9 element in a spherical tetrel deltahedron. And the discovery of [Rh@Pb12]3- also provides direct proof for previous reports on the observation of [M@Pb12]x± (clusters in mass spectrometric expts. proved by quantum-chem. calcns.). DFT computations indicate that the icosahedral cluster anion [Rh@Pb12]3- is isostructural and isoelectronic with [Ir@Sn12]3-.
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655Zhou, B.; Krämer, T.; Thompson, A. L.; McGrady, J. E.; Goicoechea, J. M. A highly distorted open-shell endohedral zintl cluster: [Mn@Pb12]3–. Inorg. Chem. 2011, 50, 8028– 8037, DOI: 10.1021/ic200329mGoogle Scholar655https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpslajtr4%253D&md5=4890727fa656219c564d36437255ac51A Highly Distorted Open-Shell Endohedral Zintl Cluster: [Mn@Pb12]3-Zhou, Binbin; Kramer, Tobias; Thompson, Amber L.; McGrady, John E.; Goicoechea, Jose M.Inorganic Chemistry (2011), 50 (17), 8028-8037CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Reaction of an ethylenediamine (en) soln. of K4Pb9 and 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) with a THF soln. of Mn3(Mes)6 (Mes = 2,4,6-trimethylphenyl) yielded the anionic cluster [Mn@Pb12]3-. This species was obsd. in the pos. and neg. ion-mode electrospray mass-spectra of the crude reaction mixt. The cryst. samples obtained from such solns. allowed the authors to confirm the compn. of the sample as [K(2,2,2-crypt)]3[Mn@Pb12]·1.5en (1). Because of numerous issues related to crystal sample quality and crystallog. disorder a high-quality crystal structure soln. could not be obtained. Despite this, however, the data collected permit the authors to draw reasonable conclusions about the charge and connectivity of the [Mn@Pb12]3- cluster anion. Crystals of 1 were further characterized by elemental anal. and EPR. D. Functional Theory (DFT) calcns. on such a system reveal a highly distorted endohedral cluster anion, consistent with the structural distortions obsd. by single crystal x-ray diffraction. The cluster anions are considerably expanded compared to the 36-electron closed-shell analog [Ni@Pb12]2- and, also, exhibit significant low-symmetry distortions from the idealized icosahedral (Ih) geometry that is characteristic of related endohedral clusters. The authors' computations indicate that there is substantial transfer of electron d. from the formally Mn(-I) center to the low-lying vacant orbitals of the [Pb12]2- cage.
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656Li, L.-J.; Pan, F.-X.; Li, F.-Y.; Chen, Z.-F.; Sun, Z.-M. Synthesis, characterization and electronic properties of an endohedral plumbaspherene [Au@Pb12]3–. Inorg. Chem. Front. 2017, 4, 1393– 1396, DOI: 10.1039/C7QI00209BGoogle Scholar656https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFCltb%252FI&md5=b789883e7745964a0d391c3760ba5c5dSynthesis, characterization and electronic properties of an endohedral plumbaspherene [Au@Pb12]3-Li, Lei-Jiao; Pan, Fu-Xing; Li, Feng-Yu; Chen, Zhong-Fang; Sun, Zhong-MingInorganic Chemistry Frontiers (2017), 4 (8), 1393-1396CODEN: ICFNAW; ISSN:2052-1553. (Royal Society of Chemistry)We report the synthesis, characterization and DFT studies of a transition-metal-encapsulated superatom compd., [K(2,2,2-crypt)]3[Au@Pb12]·2py, which adopts a distorted symmetry instead of the icosahedral structure due to the second-order Jahn-Teller effect. DFT computations revealed its chem. bonding nature and arom. character, and assigned the formal electronic structure as [Au-@Pb122-]3-.
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657Kesanli, B.; Halsig, J. E.; Zavalij, P.; Fettinger, J. C.; Lam, Y.-F.; Eichhorn, B. W. Cluster growth and fragmentation in the highly fluxional platinum derivatives of Sn94-: Synthesis, characterization, and solution dynamics of Pt2@Sn174- and Pt@Sn9H3-. J. Am. Chem. Soc. 2007, 129, 4567– 4574, DOI: 10.1021/ja065764eGoogle Scholar657https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXjt1ymsbg%253D&md5=db77f00682cab473027c949c207b3a0eCluster Growth and Fragmentation in the Highly Fluxional Platinum Derivatives of Sn94-: Synthesis, Characterization, and Solution Dynamics of Pt2@Sn174- and Pt@Sn9H3-Kesanli, Banu; Halsig, Jordan E.; Zavalij, Peter; Fettinger, James C.; Lam, Yiu-Fai; Eichhorn, Bryan W.Journal of the American Chemical Society (2007), 129 (15), 4567-4574CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Sn94- reacts with Pt(PPh3)4 in ethylenediamine/toluene solvent mixts. in the presence of 2,2,2-cryptand to give four different complexes: Rudolph's complex of proposed formula [Sn9Pt(PPh3)x]4- (2), the previously reported [Pt@Sn9Pt(PPh3)]2- ion (3), and the title complexes Pt2@Sn174- (4) and Pt@Sn9H3- (5). The use of Pt(norbornene)3 instead of Pt(PPh3)4 gives complex 4 exclusively. The structure of 4 contains two Pt atoms centered in a capsule-shaped Sn17 cage. The complex is highly dynamic in soln. showing single, mutually coupled 119Sn and 195Pt NMR resonances indicative of an intramol. liq.-like dynamic exchange process. Complex 5 was characterized by selectively decoupled 1H, 119Sn, and 195Pt NMR expts. and shows similar liq.-like fluxionality. The H atom scrambles across the cage showing small couplings to both Sn and Pt atoms. Neither 3 nor 4 obeys Wades rules; they adopt structures more akin to the subunits in alloys such as PtSn4. The structural and chem. relevance to supported PtSn4 heterogeneous catalysts is discussed.
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658Jin, X.; McGrady, J. E. In Adv. Inorg. Chem.; Elsevier: Amsterdam, 2019; Vol. 73, pp 265– 304.Google ScholarThere is no corresponding record for this reference.
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659Valden, M.; Lai, X.; Goodman, D. W. Onset of catalytic activity of gold clusters on titania with the appearance of nonmetallic properties. Science 1998, 281, 1647– 1650, DOI: 10.1126/science.281.5383.1647Google Scholar659https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtVSqu7w%253D&md5=18353418ee25f29fe784de789819cd8dOnset of catalytic activity of gold clusters on titania with the appearance of nonmetallic propertiesValden, M.; Lai, X.; Goodman, D. W.Science (Washington, D. C.) (1998), 281 (5383), 1647-1650CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Gold clusters ranging in diam. from 1 to 6 nm have been prepd. on single cryst. surfaces of titania in ultrahigh vacuum to investigate the unusual size dependence of the low-temp. catalytic oxidn. of carbon monoxide. Scanning tunneling microscopy/spectroscopy (STM/STS) and elevated pressure reaction kinetics measurements show that the structure sensitivity of this reaction on gold clusters supported on titania is related to a quantum size effect with respect to the thickness of the gold islands; islands with two layers of gold are most effective for catalyzing the oxidn. of carbon monoxide. These results suggest that supported clusters, in general, may have unusual catalytic properties as one dimension of the cluster becomes smaller than three at. spacings.
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660Pyykkö, P. Theoretical chemistry of gold. Angew. Chem., Int. Ed. 2004, 43, 4412– 4456, DOI: 10.1002/anie.200300624Google Scholar660https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2cvptFelsQ%253D%253D&md5=8df938d91d2068073332c4fbbd2cd865Theoretical chemistry of goldPyykko PekkaAngewandte Chemie (International ed. in English) (2004), 43 (34), 4412-56 ISSN:1433-7851.Gold is an element whose unique properties are strongly influenced by relativistic effects. A large body of appropriate calculations now exist and their main conclusions are summarized. The theoretical interpretation of the aurophilic attraction is discussed in detail.
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661Pyykkö, P. Theoretical chemistry of gold. II.. Inorg. Chim. Acta 2005, 358, 4113– 4130, DOI: 10.1016/j.ica.2005.06.028Google ScholarThere is no corresponding record for this reference.
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662Schooss, D.; Weis, P.; Hampe, O.; Kappes, M. M. Determining the size-dependent structure of ligand-free gold-cluster ions. Philos. Trans. R. Soc., A 2010, 368, 1211– 1243, DOI: 10.1098/rsta.2009.0269Google Scholar662https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkt1SjsL8%253D&md5=5baf0ad793add602a88ee5190f52ba36Determining the size-dependent structure of ligand-free gold-cluster ionsSchooss, Detlef; Weis, Patrick; Hampe, Oliver; Kappes, Manfred M.Philosophical Transactions of the Royal Society, A: Mathematical, Physical & Engineering Sciences (2010), 368 (1915), 1211-1243CODEN: PTRMAD; ISSN:1364-503X. (Royal Society)A review. Ligand-free metal clusters can be prepd. over a wide size range, but only in comparatively small amts. Detg. their size-dependent properties has therefore required the development of exptl. methods that allow characterization of sample sizes comprising only a few thousand mass-selected particles under well-defined collision-free conditions. In this review, we describe the application of these methods to the geometric structural detn. of Au+n and Au-n with n = 3-20. Geometries were assigned by comparing exptl. data, primarily from ion-mobility spectrometry and trapped ion electron diffraction, to structural models from quantum chem. calcns.
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663Li, J.; Li, X.; Zhai, H. J.; Wang, L. S. Au20: A tetrahedral cluster. Science 2003, 299, 864– 867, DOI: 10.1126/science.1079879Google Scholar663https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXpt1Shsw%253D%253D&md5=7c4cfef750f80b2e5da78982bea9aab0Au20: A Tetrahedral ClusterLi, Jun; Li, Xi; Zhai, Hua-Jin; Wang, Lai-ShengScience (Washington, DC, United States) (2003), 299 (5608), 864-867CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Photoelectron spectroscopy revealed that Au20 cluster has an extremely large energy gap, which is even greater than that of C60, and an electron affinity comparable with that of C60. This observation suggests that the Au20 cluster should be highly stable and chem. inert. Using relativistic d. functional calcns., we found that Au20 possesses a tetrahedral structure, which is a fragment of the face-centered cubic lattice of bulk gold with a small structural relaxation. Au20 is thus a unique mol. with at. packing similar to that of bulk gold but with very different properties.
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664Bulusu, S.; Li, X.; Wang, L.-S.; Zeng, X. C. Evidence of hollow golden cages. Proc. Natl. Acad. Sci. U. S. A. 2006, 103, 8326– 8330, DOI: 10.1073/pnas.0600637103Google Scholar664https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlvFChsbc%253D&md5=8dc4f198a63c3897eda2f869e9d03b4fEvidence of hollow golden cagesBulusu, Satya; Li, Xi; Wang, Lai-Sheng; Zeng, Xiao ChengProceedings of the National Academy of Sciences of the United States of America (2006), 103 (22), 8326-8330CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The fullerenes are the first "free-standing" elemental hollow cages identified by spectroscopy expts. and synthesized in the bulk. Here, we report exptl. and theor. evidence of hollow cages consisting of pure metal atoms, Aun- (n = 16-18). To our knowledge, free-standing metal hollow cages have not been previously detected in the lab. These hollow golden cages ("bucky gold") have an av. diam. > 5.5 Å, which can easily accommodate one guest atom inside.
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665Lechtken, A.; Neiss, C.; Kappes, M. M.; Schooss, D. Structure determination of gold clusters by trapped ion electron diffraction: Au14––Au19–. Phys. Chem. Chem. Phys. 2009, 11, 4344– 4350, DOI: 10.1039/b821036eGoogle Scholar665https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXmtFCitL4%253D&md5=2fd2e3c9ae93ee8ead9d7e677c3f80aeStructure determination of gold clusters by trapped ion electron diffraction: Au14-- Au19-Lechtken, Anne; Neiss, Christian; Kappes, Manfred M.; Schooss, DetlefPhysical Chemistry Chemical Physics (2009), 11 (21), 4344-4350CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures of mass-selected gold cluster anions Au14-- Au19- were reinvestigated using an improved low temp. trapped ion electron diffraction expt. Structures were assigned by comparing exptl. with simulated scattering functions using model structures obtained by d. functional calcns. Flat three-dimensional structures were found for Au14- and Au15-, hollow cages for Au16-- Au18- and a tetrahedral structure is found for Au19-. For several clusters in this series, our assignments differ distinctly from previous assignments.
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666Johansson, M. P.; Sundholm, D.; Vaara, J. Au32: A 24-carat golden fullerene. Angew. Chem., Int. Ed. 2004, 43, 2678– 2681, DOI: 10.1002/anie.200453986Google Scholar666https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXksVCgtLw%253D&md5=1979ac6021fa09d5d4057e55f9e67ec3Gold Fullerenes: Au32: a 24-carat golden fullereneJohansson, Mikael P.; Sundholm, Dage; Vaara, JuhaAngewandte Chemie, International Edition (2004), 43 (20), 2678-2681CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Relativistic quantum chem. theory suggests the existence of an interesting and surprising gold cluster. The all-gold fullerene Au32 is structurally very similar to the familiar buckminsterfullerene C60, as it is approx. the same size and hollow. Au32 is stabilized by relativistic effects and spherical aromaticity; the magnetic shielding at the center of the fullerene has the highest predicted value.
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667Gu, X.; Ji, M.; Wei, S. H.; Gong, X. G. AuN clusters (N = 32,33,34,35): Cagelike structures of pure metal atoms. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 205401, DOI: 10.1103/PhysRevB.70.205401Google Scholar667https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVGgsL7E&md5=c880240c23233d04ceea7d83931a5b74AuN clusters (N=32,33,34,35): cagelike structures of pure metal atomsGu, X.; Ji, M.; Wei, S. H.; Gong, X. G.Physical Review B: Condensed Matter and Materials Physics (2004), 70 (20), 205401/1-205401/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Based on the d. functional theory, we demonstrate that AuN clusters can have cagelike structures. The cage consisting of 32 Au atoms has an icosahedral symmetry with a large energy gap of 1.56 eV, suggesting high stability and chem. inertness. The calcns. show that the cagelike structure is stabilized by the relativistic effect.
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668Mingos, D. M. P. Molecular-orbital calculations on cluster compounds of gold. J. Chem. Soc., Dalton Trans. 1976, 1163– 1169, DOI: 10.1039/dt9760001163Google Scholar668https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE28XltFaqsb4%253D&md5=42e285886b5686a2207737a869287626Molecular-orbital calculations on cluster compounds of goldMingos, D. Michael P.Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry (1972-1999) (1976), (13), 1163-9CODEN: JCDTBI; ISSN:0300-9246.MO calcns. on [Au6(PPh3)6]2+, [Au9(PPh3)8]3+, and [Au11(PPh3)7X3] (X = SCN, I) cluster compds. showed that the overlap of the Au 6s orbitals makes a dominant contribution to the bonding. Coordination of ligands to the bare metal clusters encouraged a more favorable hybridization of the metal orbitals and resulted in stronger radial metal-metal bonding. The electronic factors responsible for the breakdown of the Polyhedral Skeletal Electron Pair rules when applied to the Au clusters were discussed.
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669Sato, T.; Lijnen, E.; Ceulemans, A. Jahn-Teller instability of icosahedral [W@Au12]-. J. Chem. Theory Comput. 2014, 10, 613– 622, DOI: 10.1021/ct400985uGoogle Scholar669https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFyrtrbF&md5=acac1b4d1c9904692a0af7e462ac0041Jahn-Teller Instability of Icosahedral [W@Au12]-Sato, Tohru; Lijnen, Erwin; Ceulemans, ArnoutJournal of Chemical Theory and Computation (2014), 10 (2), 613-622CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)The anionic state of the icosahedral W@Au12 cluster offers a rare example of a Jahn-Teller (JT) instability in an icosahedral fourfold degenerate Γ8 spinor level. The JT energy splittings of the ground Γ8 and excited sixfold degenerate Γ9 splittings in the vicinity of the degeneracy point were calcd. with relativistic d. functional theory. The results were very well explained by a first-order coupling model, based on the orbital instability of the spherical d-shell of the cluster. In addn. the pentagonal JT min. was detd. It presents a remarkable example of an auro-sandwich type compd.
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670Zhai, H. J.; Li, J.; Wang, L. S. Icosahedral gold cage clusters: M@Au12- (M = V, Nb, and Ta. J. Chem. Phys. 2004, 121, 8369– 8374, DOI: 10.1063/1.1799574Google Scholar670https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXptFGmt7s%253D&md5=385d6c646fc3974e1acf354a63b58398Icosahedral gold cage clusters: M@Au12- (M=V, Nb, and Ta)Zhai, Hua-Jin; Li, Jun; Wang, Lai-ShengJournal of Chemical Physics (2004), 121 (17), 8369-8374CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report the observation and characterization of a series of stable bimetallic 18-valence-electron clusters contg. a highly sym. 12-atom icosahedral Au cage with an encapsulated central heteroatom of Group VB transition metals, M@Au12- (M = V,Nb,Ta). Electronic and structural properties of these clusters were probed by anion photoelectron spectroscopy and theor. calcns. Characteristics of the M@Au-12 species include their remarkably high binding energies and relatively simple spectral features, which reflect their high symmetry and stability. The adiabatic electronic binding energies of M@Au-12 were measured to be 3.70 ± 0.03, 3.77 ± 0.03, and 3.76 ± 0.03 eV for M = V, Nb, and Ta, resp. Comparison of d.-functional calcns. with exptl. data established the highly sym. icosahedral structures for the 18-electron cluster anions, which may be promising building blocks for cluster-assembled nanomaterials in the form of stoichiometric [M@Au-12]X+ salts.
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671Autschbach, J.; Hess, B. A.; Johansson, M. P.; Neugebauer, J.; Patzschke, M.; Pyykkö, P.; Reiher, M.; Sundholm, D. Properties of WAu12. Phys. Chem. Chem. Phys. 2004, 6, 11– 22, DOI: 10.1039/B310395AGoogle Scholar671https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXpvV2lu7s%253D&md5=f84816c775f4fa90510775909e1ce8baProperties of WAu12Autschbach, Jochen; Hess, Bernd A.; Johansson, Mikael P.; Neugebauer, Johannes; Patzschke, Michael; Pyykkoe, Pekka; Reiher, Markus; Sundholm, DagePhysical Chemistry Chemical Physics (2004), 6 (1), 11-22CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The icosahedral cluster compd. WAu12 was recently predicted by P. and N. Runeberg (2002) and exptl. prepd. in the gas phase by X. Li et al. (2002). The photoelectron spectra and electron affinity were reported; the other phys. properties remain unknown. Anticipating further exptl. studies on it, vibrational spectra, NMR chem. shifts, spin-spin coupling consts., quadrupole coupling consts., and optical spectra at the level of single and double excitations are predicted. The population anal. is nontrivial. By direct numerical integration, a charge of roughly +1 is obtained for the central W atom. The charge distribution is strongly delocalized but bonding regions are clearly seen. A considerable elec. field gradient exists at the Au nuclei. Although the radial bonds are strong, the system is quite elastic. The DFT activation energy for rotating 1 hemisphere against the other 1, at a D5h transition state, is only ∼20 kJ mol-1. The corresponding hu vibrational frequency is predicted to be slightly <30 cm-1.
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672Manninen, K.; Pyykkö, P.; Hakkinen, H. A small spherical liquid: A DFT molecular dynamics study of WAu12. Phys. Chem. Chem. Phys. 2005, 7, 2208– 2211, DOI: 10.1039/b503656aGoogle Scholar672https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvFOit7o%253D&md5=893e346c844e308a248941ad6974ccdcA small spherical liquid: A DFT molecular dynamics study of WAu12Manninen, Kirsi; Pyykkoe, Pekka; Haekkinen, HannuPhysical Chemistry Chemical Physics (2005), 7 (10), 2208-2211CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The finite-temp. dynamics of WAu12, incorporating both electronic and structural effects, is studied using a d.-functional-based Born-Oppenheimer mol. dynamics method. Mol. dynamics simulations for monomol. WAu12 suggest a surface-melting-type behavior of the angular degrees of freedom between 366 and 512 K. Thermally averaged electron d.-of-states of WAu12 are compared to the exptl. photoelectron spectra of WAu12-.
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673Johansson, M. P.; Pyykkö, P. WAu12(CO)12?. Chem. Commun. 2010, 46, 3762– 3764, DOI: 10.1039/c0cc00045kGoogle Scholar673https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmtFOjur0%253D&md5=3512c60fba71d78114879dc60e130a30WAu12(CO)12?Johansson, Mikael P.; Pyykkoe, PekkaChemical Communications (Cambridge, United Kingdom) (2010), 46 (21), 3762-3764CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Calcns. (CCSD(T) and DFT-TPSSh with relativistic effective core potentials) suggest that the previously predicted and exptl. obsd. cluster WAu12 can be covered by twelve μ1-CO mols. The symmetry remains Ih and the binding energy per carbonyl is about 100 kJ mol-1 up to the last one.
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674Wang, S. Y.; Yu, J. Z.; Mizuseki, H.; Sun, Q.; Wang, C. Y.; Kawazoe, Y. Energetics and local spin magnetic moment of single 3d, 4d impurities encapsulated in an icosahedral Au12 cage. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 165413, DOI: 10.1103/PhysRevB.70.165413Google Scholar674https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXpsVGnsbc%253D&md5=15f08ea7cdcccd9a487a575ac5de6547Energetics and local spin magnetic moment of single 3,4d impurities encapsulated in an icosahedral Au12 cageWang, Shan-Ying; Yu, Jing-Zhi; Mizuseki, Hiroshi; Sun, Qiang; Wang, Chong-Yu; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 70 (16), 165413/1-165413/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The energetics and local spin magnetic moment of a single 3,4d impurity (Sc-Ni, Y-Pd) encapsulated in an icosahedral Au12 cage were studied theor. by using a real-space 1st-principles cluster method with generalized gradient approxn. for exchange-correlation functional. The relativistic effect is considered by scalar relativistic pseudopotentials. All doped clusters show unexpected large relative binding energies compared with icosahedral Au13 cluster. The smallest and the largest values appear at Pd and Zr, 2.186 and 7.791 eV per cluster, resp., indicating doping could stabilize the icosahedral Au12 cage and promote the formation of a new binary alloy cluster. Comparatively large magnetic moments are obsd. for 3d elements Cr, Mn, Fe, Co, and Ni (2.265, 3.512, 3.064, 1.947, and 0.943 μB), and 4d elements Tc, Ru, and Rh (0.758, 1.137, and 0.893 μB). The d. of states and the relativistic effects on electronic structure are discussed.
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675Long, J.; Qiu, Y.-X.; Chen, X.-Y.; Wang, S.-G. Stable geometric and electronic structures of gold-coated nanoparticles M@Au12 (M = 5d transition metals, from Hf to Hg): Ih or Oh?. J. Phys. Chem. C 2008, 112, 12646– 12652, DOI: 10.1021/jp8033006Google Scholar675https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptVGjt7Y%253D&md5=532a06df4b8ee4dfeba25386cd7f8d20Stable Geometric and Electronic Structures of Gold-Coated Nanoparticles M@Au12 (M = 5d Transition Metals, from Hf to Hg): Ih or Oh?Long, Juan; Qiu, Yi-Xiang; Chen, Xian-Yang; Wang, Shu-GuangJournal of Physical Chemistry C (2008), 112 (33), 12646-12652CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The geometries and electronic structures of 5d transition metal "impurities" Hf to Hg encapsulated in icosahedral and cuboctahedral Au12 cages were investigated theor. The best d. functional results of the small test mols. Au2, AuH, AuCl, and AuCu were obtained for the geometric structures with Xα, and for the electronic energies of those frozen structures with VBP. The same procedure was then applied to the clusters. At the zeroth order regular relativistic approxn. ZORA, both at the spin-averaged scalar and at the spin-orbit-split spinor levels, the cuboctahedral clusters tend to be more stable than their icosahedral isomers, except for W@Au12. The neutral clusters have electronic closed shells only for Ih and Oh W@Au12 and for Oh Hg@Au12. The embedding energy of M into Au12 is less attractive for the later transition metal atoms M.
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676Nijamudheen, A.; Jose, D.; Datta, A. Metal encapsulation mediated planar to three dimensional structural transformation in Au-clusters: The venus flytrap effect. Comput. Theor. Chem. 2011, 966, 133– 136, DOI: 10.1016/j.comptc.2011.02.025Google Scholar676https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXlvVWmurY%253D&md5=4eb0dadc9d37ed2c21d22d04cdfdd2dcMetal encapsulation mediated planar to three dimensional structural transformation in Au-clusters: The venus flytrap effectNijamudheen, A.; Jose, Deepthi; Datta, AyanComputational & Theoretical Chemistry (2011), 966 (1-3), 133-136CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)DFT calcns. on small Au12 clusters reveal a side-wise folding mechanism of this planar cluster in the presence of added transition-metal atoms or ions like Cr, Mo, W, V-, Nb-, Ta-, Mn+, Tc+ and Re+. Such a process is highly exothermic and leads to the formation of an 18 electron closed shell structure. The barriers for such a conversion is small and the exptl. strategies are proposed for favorable observation of such a process.
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677Zhang, C.-H.; Cui, H.; Shen, J. The 13-atom encapsulated gold cage clusters. Chin. Phys. B 2012, 21, 103102, DOI: 10.1088/1674-1056/21/10/103102Google Scholar677https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlGnu7fF&md5=5d0add0f4e570e7de66f9c02278f317bThe 13-atom encapsulated gold cage clustersZhang, Chuan-Hui; Cui, Hang; Shen, JiangChinese Physics B (2012), 21 (10), 103102/1-103102/5CODEN: CPBHAJ; ISSN:1674-1056. (IOP Publishing Ltd.)The structure and the magnetic moment of transition metal encapsulated in a Au12 cage cluster have been studied by using the d. functional theory. The results show that all of the transition metal atoms (TMA) can embed into the Au12 cage and increase the stability of the clusters except Mn. Half of them have the Ih or Oh symmetry. The curves of binding energy have oscillation characteristics when the extra-nuclear electrons increase; the reason for this may be the interaction between parity changes of extra-nuclear electrons and Au atoms. The curves of HOMO-LUMO (HOMO-LUMO) gap also have oscillation characteristics when the extra-nuclear electrons increase. The binding energies of many M@Au12 clusters are much larger than that of the pure Au13 cluster, while the gaps of some of them are less than that of Au13, so maybe Cr@Au12, Nb@Au12, and W@Au12 clusters are most stable in fact. For magnetic calcns., some clusters are quenched totally, but the Au13 cluster has the largest magnetic moment of 5 μB. When the no. of extra-nuclear electrons of the encapsulated TMA is even, the magnetic moment of relevant M@Au12 cluster is even, and so are the odd ones.
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678Raggi, G.; Soto, J. R. Relativistic DFT calculations of magnetic moments of pristine and thiolated Mn@Aux (x = 6, 12). Phys. Chem. Chem. Phys. 2014, 16, 21506– 21512, DOI: 10.1039/C4CP03036BGoogle Scholar678https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVSmt7bL&md5=5e7ab82514214601fc72385490e88738Relativistic DFT calculations of magnetic moments of pristine and thiolated Mn@Aux (x = 6, 12)Raggi, G.; Soto, J. R.Physical Chemistry Chemical Physics (2014), 16 (39), 21506-21512CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The authors present the results of relativistic DFT calcns. of magnetic moments for Mn inserted into a Au ring (Mn@Au6) or a cage-like structure (Mn@Au12) both pristine and n-thiolated. Optimization was carried out to obtain different isomers always favoring the endohedral Au clusters with Mn inside. For the total magnetic moment (from electronic population anal.) verification of the jellium model was performed in each case. The magnetic moments arise largely from the doped Mn atom and thiolation can modulate its value, which is not present in the pure form. In the Mn@Au12 clusters the authors obsd. the formation of a hole in their structure; this could be a characteristic of insertion of a highly ferromagnetic dopant in some metal clusters, such as Au, and this could act as a precursor of the formation of Au magnetic nanotubes.
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679Yarzhemsky, V. G.; Izotov, A. D.; Kazaryan, M. A.; D’Yakov, Y. A. Structure of endohedral clusters Au12M. Dokl. Chem. 2015, 462, 115– 117, DOI: 10.1134/S0012500815050031Google Scholar679https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXps1Srurw%253D&md5=c0a4e5965821469d4c035f21b370f572Structure of endohedral clusters Au12MYarzhemsky, V. G.; Izotov, A. D.; Kazaryan, M. A.; D'yakov, Yu. A.Doklady Chemistry (2015), 462 (1), 115-117CODEN: DKCHAY; ISSN:0012-5008. (SP MAIK Nauka/Interperiodica)The present article deals with the study of formation of 13-atom clusters contg. 12 gold atoms and one 4d- or 5d-metal atom. The chem. properties of such clusters are similar to the properties of AuN (N < 14) clusters, and their structure is more compact. The structure of endohedral clusters Au12M were studied.
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680Cao, G.-J.; Schwarz, W. H. E.; Li, J. An 18-electron system containing a superheavy element: Theoretical studies of Sg@Au12. Inorg. Chem. 2015, 54, 3695– 3701, DOI: 10.1021/acs.inorgchem.5b00356Google Scholar680https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkvF2htrs%253D&md5=4bb3fb1e37880df8ad134f6099410897An 18-Electron System Containing a Superheavy Element: Theoretical Studies of Sg@Au12Cao, Guo-Jin; Schwarz, W. H. Eugen; Li, JunInorganic Chemistry (2015), 54 (7), 3695-3701CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)M@Au12 cage mols. (M = transition element from group 6) are interesting clusters with high-sym. structure and significant stability. As the heavier homolog of W is 106Sg, it is interesting to pinpoint whether the Sg@Au12 cluster is also stable. Geometric and electronic structures and bonding of various Sg@Au12 isomers were investigated with d. functional theory (PW91, PBE, B3LYP) and wave function theory (MP2, CCSD(T)) approaches. The lowest-energy isomer of Sg@Au12 has icosahedral symmetry with significant Sg(6d)-Au(6s) covalent-metallic interaction and is comparable to the lighter homologues (M = Mo, W), with similar binding energy, although Sg follows (as a rare case) the textbook rule "ns below (n - 1)d". The 12 6s valence electrons from Au12 and the six 7s6d ones from Sg can be viewed as an 18e system below and above the interacting Au 5d band, forming nine delocalized multicenter bond pairs with a high stability of ∼0.8 eV of bond energy per each of the 12 Sg-Au contacts. Different prescriptions (orbital, multipole-deformation, charge-partition, and X-ray-spectroscopy based ones) assign ambiguous at. charges to the centric and peripheral atoms; at. core-level energy shifts correspond to some neg. charge shift to the gold periphery, more so for Cr@Au12 than for Sg@Au12 or Au@Au12.
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681Muñoz-Castro, A. Golden endohedral main-group clusters, [E@Au12]q-: Theoretical insights into the 20-e principle. J. Phys. Chem. Lett. 2013, 4, 3363– 3366, DOI: 10.1021/jz401622mGoogle Scholar681https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVylsr%252FF&md5=5bf7159817f76da53660541b389f8a78Golden Endohedral Main-Group Clusters, [E@Au12]q-: Theoretical Insights Into the 20-e PrincipleMunoz-Castro, AlvaroJournal of Physical Chemistry Letters (2013), 4 (19), 3363-3366CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The inclusion of a transition metal (M) into an icosahedral Au12 cage ([M@Au12]q), was theor. predicted prior to its exptl. characterization on the basis of the jellium model, where the titled system is in accordance with the 18-ve principle fulfilling a 1s21p61d10 electronic configuration. In contrast, the inclusion of a p-block element (E) seems not to follow such principle, leading to an open-shell state that in turn exhibits a Jahn-Teller distortion. Hence, the icosahedral structure is no longer the more stable situation. We rationalize the electronic structure of [E@Au12],q denoting the interaction between the endohedral element and the golden cage, which rise to a 1s21p62s21d10 electronic configuration requiring 20-ve as an extension to the 18-ve principle. The 20-ve count is valid in almost the whole series, with the exception given by E = N, O, F, Cl, and Br.
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682Muñoz-Castro, A. Doping the cage. Re@Au11Pt and Ta@Au11Hg, as novel 18-ve trimetallic superatoms displaying a doped icosahedral golden cage. Phys. Chem. Chem. Phys. 2017, 19, 2459– 2465, DOI: 10.1039/C6CP07519CGoogle Scholar682https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVOksrnK&md5=a6952f07dcedbb0acc776e766bc16392Doping the cage. Re@Au11Pt and Ta@Au11Hg, as novel 18-ve trimetallic superatoms displaying a doped icosahedral golden cageMunoz-Castro, AlvaroPhysical Chemistry Chemical Physics (2017), 19 (3), 2459-2465CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Expanding the versatility of well defined clusters is a major concern in the design of building blocks towards functional nanostructures. W@Au12 is a prototypical binary bare superat. cluster involving an icosahedral symmetry, which has been discussed in the literature, precluding the proposal of several endohedral d-block and f-block element structures within a golden cage. Here we pursue the construction of related trimetallic clusters, which has been explored to a lesser extent. Our results expose the great advantages of involving heterocages in the superatom approach, unraveling Re@Au11Pt and Ta@Au11Hg as novel trimetallic candidates. Re@Au11Pt exhibits an electron-deficient element in the cage, and an endohedral atom with an extra electron. In contrast, Ta@Au11Hg is conceived as having an icosahedral cage with an extra electron, and an electron-deficient endohedral element. These new clusters follow the eighteen valence electron principle, with similar characteristics to their W@Au12 parent. This leads to stable clusters with an electronic structure formally described by the 1s21p61d10 closing shell order, showing an interesting approach to design ternary superatoms, where the variation of valence electrons occurs in both cage and endohedral sites. Moreover, the cage doping appears as a useful approach to further evaluate the formation of magnetic superatoms, and also the construction of larger clusters by fusing different icosahedral structures.
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683Stener, M.; Nardelli, A.; Fronzoni, G. Spin-orbit effects in the photoabsorption of WAu12 and MoAu12: A relativistic time dependent density functional study. J. Chem. Phys. 2008, 128, 134307, DOI: 10.1063/1.2884003Google Scholar683https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXksF2lu7o%253D&md5=920f898dc3fc3e78f899cff26f64fd45Spin-orbit effects in the photoabsorption of WAu12 and MoAu12: A relativistic time dependent density functional studyStener, M.; Nardelli, A.; Fronzoni, G.Journal of Chemical Physics (2008), 128 (13), 134307/1-134307/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic structure of both WAu12 and MoAu12 was calcd. at the d. functional theory (DFT) level, employing the zero order regular approxn. at the scalar relativistic level and including a spin-orbit coupling. The effect of the inclusion of the spin-orbit coupling is discussed, and the differences assigned to the nature of the encaged atom (W or Mo) are identified. Then, the excitation spectra of both clusters are calcd. at the time-dependent DFT level, also in this case at both scalar relativistic and spin-orbit levels. The inclusion of spin-orbit coupling is mandatory for an accurate description in the low energy region. At higher energy, where the d. of states is higher, the convoluted intensity can be properly described already at the scalar relativistic level. The consequences of the spin-orbit coupling on the excitation spectrum of the clusters indicate that while in WAu12 the lowest excitations are essentially shifted in energy with respect to the scalar relativistic results, in MoAu12, a dramatic splitting in many lines is actually predicted, revealing a quite different behavior of the two clusters. (c) 2008 American Institute of Physics.
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684Stener, M.; Nardelli, A.; Fronzoni, G. Theoretical study on the photoabsorption of MAu12- (M = V, Nb and Ta). Chem. Phys. Lett. 2008, 462, 358– 364, DOI: 10.1016/j.cplett.2008.08.010Google Scholar684https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGlu7zJ&md5=326c06eaff0332366488da4f8c11557fTheoretical study on the photoabsorption of MAu12- (M = V, Nb and Ta)Stener, M.; Nardelli, A.; Fronzoni, G.Chemical Physics Letters (2008), 462 (4-6), 358-364CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The valence photoabsorption spectra of the monoanionic closed shell icosahedral clusters M Au 12 - with M = V, Nb and Ta were calcd. with the time-dependent d. functional theory (TDDFT), employing the zero-order regular approxn. (ZORA) at both scalar relativistic and spin-orbit coupling levels. The calcd. photoabsorption spectra show interesting variations according to the nature of the encapsulated metal atom. Spin-orbit coupling plays an important role in these systems. The comparison with the neutral isoelectronic clusters WAu12 and MoAu12 suggests a curious relation along the diagonal of the periodic table.
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685Ju, W.; Yang, Z. Influence of spin-orbit coupling on electronic structures of TM@Au12 (TM = 3d, 4d, and 5d atoms). Phys. Lett. A 2012, 376, 1300– 1305, DOI: 10.1016/j.physleta.2012.02.052Google Scholar685https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjt1Orurw%253D&md5=4799e4126a78736cc9a9955d6583f425Influence of spin-orbit coupling on electronic structures of TM@Au12 (\\TM=3d\\, 4d, and 5d atoms)Ju, Weiwei; Yang, ZhongqinPhysics Letters A (2012), 376 (15), 1300-1305CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)Influence of spin-orbit coupling (SOC) on electronic structures of TM@Au12 (\\TM=3d\\, 4d, and 5d transition-metal atoms) is studied by using d. functional theory. The SOC can disperse much the frontier energy levels of the clusters, esp. for the clusters with TM atoms at the end of each series. The SOC generally decrease the gaps of the frontier orbitals and the spin magnetic moments due to the orbital dispersion and increase of hybridization between the TM and the host atoms, resp. Considerable orbital magnetic moments can be obtained. Our work provides imperative understanding on SOC effects in transition-metal clusters.
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686Muñoz-Castro, A.; Arratia-Perez, R. Spin-orbit effects on a gold-based superatom: A relativistic Jellium model. Phys. Chem. Chem. Phys. 2012, 14, 1408– 1411, DOI: 10.1039/C1CP22420DGoogle Scholar686https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1Kqsb3O&md5=c5b6ab837b049de08d80fcbb9b93309dSpin-orbit effects on a gold-based superatom: a relativistic Jellium modelMunoz-Castro, Alvaro; Arratia-Perez, RamiroPhysical Chemistry Chemical Physics (2012), 14 (4), 1408-1411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The inclusion of relativistic effects always brings to the scientific community great and stimulating surprises. To consider the spin-orbit term, which accounts for the interaction between the spatial and spin coordinates, requires the use of double point groups of symmetry in order to solve the Dirac equation or the two component approxn. to it, leading to total angular momenta (j) functions, at. or mol. spinors, instead of pure orbital angular momenta (l), at. or MOs. Large and small components, derived from the Dirac treatment, depict wavefunctions corresponding to fermions, electrons, which are described for the first time for a superatom case. In addn., their behavior is revisited in order to clarify the effects of the inclusion of the spin-orbit coupling into the electronic structure calcns., which can be extended to other superatoms, clusters, mols. and atoms.
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687Hossain, D.; Pittman, C. U., Jr.; Gwaltney, S. R. Structures and stabilities of the metal doped gold nano-clusters: M@Au10 (M = W, Mo, Ru, Co). J. Inorg. Organomet. Polym. Mater. 2014, 24, 241– 249, DOI: 10.1007/s10904-013-9995-6Google Scholar687https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslWltLvN&md5=ddf23db079b93b16d43702b826178843Structures and Stabilities of the Metal Doped Gold Nano-Clusters: M@Au10 (M = W, Mo, Ru, Co)Hossain, Delwar; Pittman, Jr., Charles U.; Gwaltney, Steven R.Journal of Inorganic and Organometallic Polymers and Materials (2014), 24 (1), 241-249CODEN: JIOPAY; ISSN:1574-1443. (Springer)The structures and stabilities of a series of endohedral gold clusters contg. ten gold atoms M@Au10 (M = W, Mo, Ru, Co) have been detd. using d. functional theory. The gradient-cor. functional BP86, the Tao-Perdew-Staroverov-Scuseria TPSS meta-GGA functional, and the hybrid d. functionals B3LYP and PBE1PBE were employed to calc. the structures, binding energies, adiabatic ionization potentials, and adiabatic electron affinities for these clusters. The LanL2DZ effective core potentials and the corresponding valence basis sets were employed. The M@Au10 (M = W, Mo, Ru, Co) clusters have higher binding energies than an empty Au10 cluster. In addn., the large HOMO-LUMO gaps suggest that the M@Au10 (M = W, Mo, Ru, Co) clusters are all likely to be stable chem. The ionization potentials and electron affinities for these clusters are very high, and the W@Au10 and Mo@Au10 clusters have electron affinities similar to the super-halogen Al13.
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688Nhat, P. V.; Nguyen, M. T. Trends in structural, electronic and energetic properties of bimetallic vanadium-gold clusters AunV with n = 1-14. Phys. Chem. Chem. Phys. 2011, 13, 16254– 16264, DOI: 10.1039/c1cp22078kGoogle Scholar688https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFSjsbnP&md5=1a119356395376c402c8e779cd551972Trends in structural, electronic and energetic properties of bimetallic vanadium-gold clusters AunV with n = 1-14Nhat, Pham Vu; Nguyen, Minh ThoPhysical Chemistry Chemical Physics (2011), 13 (36), 16254-16264CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)A systematic quantum chem. investigation on the electronic, geometric and energetic properties of AunV clusters with n = 1-14 in both neutral and anionic states is performed using DFT-BP86/cc-pVTZ-PP calcns. Most clusters having an even no. of electrons prefer a high spin state. For odd-electron systems, a quartet state is consistently favored as the ground state up to Au8V. The larger sized Au10V, Au12V and Au14V prefer a doublet state. The clusters prefer 2D geometries up to Au8V involving a weak charge transfer. The larger systems bear 3D conformations with a more effective electron transfer from Au to V. The lowest-energy structure of a size AunV is built upon the most stable form of Aun-1V. During the growth, V is endohedrally doped in order to maximize its coordination nos. and augment the charge transfer. Energetic properties, including the binding energies, embedding energies and second-order energy differences, show that the presence of a V atom enhances considerably the thermodn. stability of odd-numbered gold clusters but reduces that of even-numbered systems. The at. shape has an apparently more important effect on the clusters stability than the electronic structure. Esp., if both at. shape and electronic condition are satisfied, the resulting cluster becomes particularly stable such as the anion Au12V-, which can thus combine with the cation Au+ to form a superat. mol. of the type [Au12V]Au. Numerous lower-lying electronic states of these clusters are very close in energy, in such a way that DFT computations cannot clearly establish their ground electronic states. Calcd. results demonstrate the existence of structural isomers with comparable energy content for several species including Au9V, Au10V, Au13V and Au14V.
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689Blades, W. H.; Reber, A. C.; Khanna, S. N.; Lopez-Sosa, L.; Calaminici, P.; Koster, A. M. Evolution of the spin magnetic moments and atomic valence of vanadium in VCux+, VAgx+, and VAux+ clusters (x = 3-14). J. Phys. Chem. A 2017, 121, 2990– 2999, DOI: 10.1021/acs.jpca.7b01030Google Scholar689https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXltVSqtr8%253D&md5=ec06c94f1b93c4d73ce65a232f381ed5Evolution of the Spin Magnetic Moments and Atomic Valence of Vanadium in VCux+, VAgx+, and VAux+ Clusters (x = 3-14)Blades, William H.; Reber, Arthur C.; Khanna, Shiv N.; Lopez-Sosa, Luis; Calaminici, Patrizia; Koster, Andreas M.Journal of Physical Chemistry A (2017), 121 (15), 2990-2999CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The at. structures, bonding characteristics, spin magnetic moments, and stability of VCux+, VAgx+, and VAux+ (x = 3-14) clusters were examd. using d. functional theory. Our studies indicate that the effective valence of vanadium is size-dependent and that at small sizes some of the valence electrons of vanadium are localized on vanadium, while at larger sizes the 3d orbitals of the vanadium participate in metallic bonding eventually quenching the spin magnetic moment. The electronic stability of the clusters may be understood through a split-shell model that partitions the valence electrons in either a delocalized shell or localized on the vanadium atom. A MO anal. reveals that in planar clusters the delocalization of the 3d orbital of vanadium is enhanced when surrounded by gold due to enhanced 6s-5d hybridization. Once the clusters become three-dimensional, this hybridization is reduced, and copper most readily delocalizes the vanadium's valence electrons. By understanding these unique features, greater insight is offered into the role of a host material's electronic structure in detg. the bonding characteristics and stability of localized spin magnetic moments in quantum confined systems.
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690Du, Q.; Wu, X.; Wang, P.; Wu, D.; Sai, L.; King, R. B.; Park, S. J.; Zhao, J. Structure evolution of transition metal-doped gold clusters M@Au12 (M = 3d–5d): Across the periodic table. J. Phys. Chem. C 2020, 124, 7449– 7457, DOI: 10.1021/acs.jpcc.9b11588Google Scholar690https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXkslWmtbk%253D&md5=f00ac7b00aef6edae3470cbcff8dc710Structure Evolution of Transition Metal-doped Gold Clusters M@Au12 (M = 3d-5d): Across the Periodic TableDu, Qiuying; Wu, Xue; Wang, Pengju; Wu, Di; Sai, Linwei; King, R. Bruce; Park, Sung Jin; Zhao, JijunJournal of Physical Chemistry C (2020), 124 (13), 7449-7457CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The comprehensive genetic algorithm (CGA) incorporated with d. functional theory (DFT) calcns. were used for a global search of the potential energy surfaces of M@Au12 (M = 3d-5d) clusters. The feasibility of the revTPSS functional was confirmed by comparison between exptl. and calcd. data such as bond lengths and vibrational frequencies of transition metal dimers. We found the ground state structures of Mo/W@Au12 clusters to be the perfect icosahedron cage. The V/Nb/Ta/Tc/Re@Au12 clusters were found to have the distorted icosahedron cages owing to Jahn-Teller effects. The lowest energy structures of Sc/Ti/Cr/Mn/Fe/Co/Ru/Rh/Ir@Au12 have the perfect or distorted magnetic cuboctahedron cages, which can be explained by a 14-electron rule in a cuboctahedral ligand field (M2+@Au122-). Y/Zr/La/Hf@Au12 clusters have the half-cage ground states, while Ni/Cu/Zn/Pt/Ag/Cd/Pd/Au/HgAu12 clusters have oblate ground states. The scalar relativistic X2C method combined with revTPSS/TZP were used to calc. the energy difference between the magnetic cuboctahedron ground state and the icosahedron isomers of Cr@Au12 using energy decompn. anal.-natural orbitals for chem. valence. The magnetic M2+@Au122- model was found to significantly enhance the d orbital interactions of transition metal atoms and reduce Pauli repulsion, resulting in magnetic cuboctahedra as the more stable structures.
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691Carey, D. M.; Muñoz-Castro, A. Au11Re: A hollow or endohedral binary cluster?. Chem. Phys. Lett. 2018, 701, 30– 33, DOI: 10.1016/j.cplett.2018.04.038Google ScholarThere is no corresponding record for this reference.
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692Gao, Y.; Bulusu, S.; Zeng, X. C. Gold-caged metal clusters with large HOMO-LUMO gap and high electron affinty. J. Am. Chem. Soc. 2005, 127, 15680– 15681, DOI: 10.1021/ja055407oGoogle Scholar692https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFahsrrP&md5=9715de7909b49341856d003c74b64ba3Gold-Caged Metal Clusters with Large HOMO-LUMO Gap and High Electron AffinityGao, Yi; Bulusu, Satya; Zeng, Xiao ChengJournal of the American Chemical Society (2005), 127 (45), 15680-15681CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report a series of isoelectronic gold-caged metal clusters, Zr@Au14 and Hf@Au14, and anion clusters, Sc@Au14- and Y@Au14-, all having a calcd. HOMO-LUMO gap larger than the well-known tetrahedral cluster Au20, the 3D metal cluster with a very large measured HOMO-LUMO gap (1.77 eV). The clusters M@Au14 (M = Sc, Y) also exhibit a calcd. electron affinity (EA) and vertical detachment energy (VDE) not only higher than the "superhalogen" icosahedral Al13 cluster but also possibly even higher than a Cl atom which has the highest (measured) elemental EA or VDE (3.61 eV).
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693Xie, J. R. H.; Cheung, C. F.; Zhao, J. J. Tuning optical absorption and emission of sub-nanometer gold-caged metal systems M@Au14 by substitutional doping. J. Comput. Theor. Nanosci. 2006, 3, 312– 314, DOI: 10.1166/jctn.2006.3013Google Scholar693https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xktlalt7w%253D&md5=79e9574a5b9e9371d97b13e735276c1cTuning optical absorption and emission of sub-nanometer gold-caged metal systems M@Au14 by substitutional dopingXie, John R. H.; Cheung, Chiu Fung; Zhao, JijunJournal of Computational and Theoretical Nanoscience (2006), 3 (2), 312-314CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)Gao, Bulusu, and Zeng have recently reported a new series of isoelectronic, sub-nanometer Au-caged metal systems M@Au14 which have large energy gaps than icosahedral W@Au12 and Au32 and tetrahedral Au20. In this communication, we propose a tuning scheme, substitutional-doping, to achieve the tunable optical excitation and emission of M@Au14 over a broad wavelength region. For example, the optical absorption gaps of isoelectronic M@Au14 could be tuned from the near-IR to green by substituting the metal M with group IIIB, IVB, and VB constituents in the periodic table. Our results provide basic guidelines for further exptl. studies on the spectral properties of M@Au14 as well as for the development of M@Au14-based tunable optoelectronic devices.
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694Toprek, D.; Koteski, V. Ab initio calculations of the structure, energetics and stability of AunTi (n = 1-32) clusters. Comput. Theor. Chem. 2016, 1081, 9– 17, DOI: 10.1016/j.comptc.2016.02.005Google Scholar694https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xislyjurk%253D&md5=135fcc4bb8b9075604dcef09953e9768Ab initio calculations of the structure, energetics and stability of AunTi (n = 1-32) clustersToprek, Dragan; Koteski, VasilComputational & Theoretical Chemistry (2016), 1081 (), 9-17CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The stability and structure of titanium doped gold clusters (AunTi; n = 1-32) are studied by d. functional theory calcns., as implemented in the first principles code SIESTA. The exchange and correlation effects were calcd. within the generalized gradient approxn. (GGA) parametrized by Perdew, Burke and Ernzerhof (PBE). We used norm conserving Troullier-Martins pseudopotentials for the 10-electron valence configuration of Ti and 11-electron valence configuration of Au. All calcns. were spin-polarized. The global energy min. geometries of the clusters were searched for by using the simulated annealing technique. The stability of the clusters is discussed on the basis of the binding energy per atom, second-order energy difference, vertical ionization potential, vertical electron affinities, HOMO-LUMO energy gap and vibrational frequencies. Based on the simultaneous criteria of high binding energy, high band gap, high vertical ionization potential, and low electron affinity, it is found that Au4Ti and Au14Ti clusters have a higher stability and are candidates for "magic clusters", which confirms the already known results from previous works. The new result presented in this paper is that the Au20Ti and Au30Ti clusters have a higher stability too. In general, the clusters with even n are more stable than the clusters with odd n. Most of the clusters with even n are non-magnetic (total magnetic moment is zero). Our results also suggest that only the Au3Ti, Au7Ti and Au8Ti clusters have a planar structure.
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695Chen, M.-X.; Yan, X. A new magic titanium-doped gold cluster and orientation dependent cluster-cluster interaction. J. Chem. Phys. 2008, 128, 174305, DOI: 10.1063/1.2916588Google Scholar695https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlslGht7g%253D&md5=664495088de7f98324d9132b4feb7500A new magic titanium-doped gold cluster and orientation dependent cluster-cluster interactionChen, Ming-Xing; Yan, X. H.Journal of Chemical Physics (2008), 128 (17), 174305/1-174305/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The stability and structures of titanium-doped gold clusters AunTi (n = 2-16) are studied by the relativistic all-electron d.-functional calcns. The most stable structures for AunTi clusters with n = 2-7 are found to be planar. A structural transition of AunTi clusters from two-dimensional to three-dimensional geometry occurs at n = 8, while the AunTi (n = 12-16) prefer a gold cage structure with Ti atom locating at the center. Binding energy and second-order energy differences indicate that the Au14Ti has a significantly higher stability than its neighbors. A high ionization potential, low electron affinity, and large energy gap being the typical characters of a magic cluster are found for the Au14Ti. For cluster-cluster interaction between magic transition-metal-doped gold clusters, calcns. were performed for cluster dimers, in which the clusters have an icosahedral or nonicosahedral structure. Both electronic shell effect and relative orientation of clusters are responsible for the cluster-cluster interaction. (c) 2008 American Institute of Physics.
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696Zhang, M.; Zhang, H.; Zhao, L.; Li, Y.; Luo, Y. Low-energy isomer identification, structural evolution, and magnetic properties in manganese-doped gold clusters MnAun (n = 1-16). J. Phys. Chem. A 2012, 116, 1493– 1502, DOI: 10.1021/jp2094406Google Scholar696https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XktVGksw%253D%253D&md5=74ef42f063c07f7f06194fb1f5d033c3Low-Energy Isomer Identification, Structural Evolution, and Magnetic Properties in Manganese-Doped Gold Clusters MnAun (n = 1-16)Zhang, Meng; Zhang, Hongyu; Zhao, Lina; Li, Yan; Luo, YouhuaJournal of Physical Chemistry A (2012), 116 (6), 1493-1502CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The size-dependent electronic, structural, and magnetic properties of Mn-doped gold clusters were systematically studied by using relativistic all-electron d. functional theory with generalized gradient approxn. A no. of new isomers were obtained for neutral MnAun (n = 1-16) clusters to probe the structural evolution. The two-dimensional (2D) to three-dimensional (3D) transition occurs in the size range n = 7-10 with manifest structure competitions. From size n = 13 to n = 16, the MnAun prefers a gold cage structure with Mn atom locating at the center. The relative stabilities of the ground-state MnAun clusters show a pronounced odd-even oscillation with the no. of Au atoms. The magnetic moments of MnAun clusters vary from 3 μB to 6 μB with the different cluster size, suggesting that nonmagnetic Aun clusters can serve as a flexible host to tailor the dopant's magnetism, which has potential applications in new nanomaterials with tunable magnetic properties.
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697Gao, Y.; Dai, X.; Kang, S.-g.; Jimenez-Cruz, C. A.; Xin, M.; Meng, Y.; Han, J.; Wang, Z.; Zhou, R. Structural and electronic properties of uranium-encapsulated Au14 cage. Sci. Rep. 2015, 4, 5862, DOI: 10.1038/srep05862Google ScholarThere is no corresponding record for this reference.
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698Gao, Y.; Wang, B.; Lei, Y.; Teo, B. K.; Wang, Z. Actinide-embedded gold superatom models: Electronic structure, spectroscopic properties, and applications in surface-enhanced Raman scattering. Nano Res. 2016, 9, 622– 632, DOI: 10.1007/s12274-015-0942-4Google Scholar698https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVKgtbo%253D&md5=a46ff5e940691efb70096aee00fb430fActinide-embedded gold superatom models: Electronic structure, spectroscopic properties, and applications in surface-enhanced Raman scatteringGao, Yang; Wang, Bo; Lei, Yanyu; Teo, Boon K.; Wang, ZhigangNano Research (2016), 9 (3), 622-632CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)Actinide elements encaged in a superat. cluster can exhibit unique properties due to their hyperactive valence electrons. Herein, the electronic and spectroscopic properties of Th@Au14 are predicted and compared with that of the isoelectronic entities [Ac@Au14]- and [Pa@Au14]+ using d. functional theory. The calcn. results indicate that these clusters all adopt a closedshell superat. 18-electron configuration of the 1S21P61D10 Jellium state. The absorption spectrum of Th@Au14 can be interpreted by the Jelliumatic orbital model. In addn., calcd. spectra of pyridine-Th@Au14 complexes in the blue laser band exhibit strong peaks attributable to charge transfer (CT) from the metal to the pyridine mol. These charge-transfer bands lead to a resonant surface-enhanced Raman scattering (SERS) enhancement of ∼104. This work suggests a basis for designing and synthesizing SERS substrate materials based on actinide-embedded gold superatom models. [Figure not available: see fulltext.].
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699Gao, Y.; Liu, X.; Wang, Z. Ce@Au14: A bimetallic superatom cluster with 18-electron rule. J. Electron. Mater. 2017, 46, 3899– 3903, DOI: 10.1007/s11664-016-4934-2Google Scholar699https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsFKqsrfP&md5=cc27f3d5d54edce67ff97a5249fed180Ce@Au14: A Bimetallic Superatom Cluster with 18-Electron RuleGao, Yang; Liu, Xizhe; Wang, ZhigangJournal of Electronic Materials (2017), 46 (7), 3899-3903CODEN: JECMA5; ISSN:0361-5235. (Springer)Doping of gold clusters and nanoparticles has received substantial attention due to their ability to encapsulate atoms and mols. Here, the geometric and electronic properties of the cerium-encapsulated nanocage Ce@Au14 are reported using d. functional theory. Calcd. results show that its ground electronic state is a singlet state and conforms to the superat. 18-electron configuration of 1S21P61D10 jellium state, both primarily involving the bonding interaction between s- and d-shell AOs of the Ce atom and superat. orbitals of the hollow polyhedral Au14 cage. In addn., it should be noted that f electrons in rare earth atoms trend to retain their localized state, and their doping in gold clusters could easily lead to clusters with large magnetic moments. However, in the case of superatom clusters, the f-shell electrons will be the preferential arrangement at the unfilled d-shell to satisfy the superat. electron structure. Further anal. of the electronic structure also proves that the unoccupied 1F superat. orbitals mainly originate from the contribution of the 4f-shell. As a consequence, this work provides a theor. basis for the future design and synthesis of f-elements-encapsulated gold nanoclusters.
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700Gao, Y.; Jiang, W.; Xu, D.; Wang, Z. Localization-vs-delocalization of 5f orbitals in superatom systems. Adv. Theory Simul. 2018, 1, 1700038, DOI: 10.1002/adts.201700038Google ScholarThere is no corresponding record for this reference.
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701Yong, Y.; Li, X.; Zhou, Q.; Su, X.; Li, T.; Cui, H.; Lv, S. Adsorption of gas molecules on Gd@Aun (n = 14, 15) clusters and their implication for molecule sensors. RSC Adv. 2016, 6, 26809– 26816, DOI: 10.1039/C6RA01136EGoogle Scholar701https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xjs1Git7o%253D&md5=2a68436bd3c8488e03980de2b98f1c3dAdsorption of gas molecules on Gd@Aun (n = 14, 15) clusters and their implication for molecule sensorsYong, Yongliang; Li, Xiaohong; Zhou, Qingxiao; Su, Xiangying; Li, Tongwei; Cui, Hongling; Lv, ShijieRSC Advances (2016), 6 (32), 26809-26816CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)First-principles calcns. are performed to study the adsorption of CO, NO, NO2, O2, CO2, N2, and H2O mols. on Gd@Aun (n = 14, 15) clusters. The adsorption geometries, adsorption energies, charge transfer, and electronic properties are obtained. We find that the toxic mols. (CO, NO, and NO2) are chem. adsorbed on the Gd@Aun (n = 14, 15) clusters with strong binding, and this can lead to finite charge transfer, while other common mols. (O2, CO2, N2, and H2O) are physisorbed on the Gd@Aun (n = 14, 15) clusters, expect for O2 mols. on the Gd@Au14 cluster. The electronic properties of the Gd@Aun (n = 14, 15) clusters are significantly influenced by NO and NO2 adsorption, esp. their elec. cond. Furthermore, for the Gd@Au15 cluster, it is found that the adsorption energy (Eads) of -0.498 eV for NO and -0.725 eV for NO2 corresponds to recovery times of about 7 × 10-12 and 11.8 s, resp., indicating that the Gd@Au15 cluster should be a good NO and NO2 sensor with quick response and short recovery time. However, the very strong adsorption of NO and NO2 on the Gd@Au14 cluster (Eads ≥ 1.00 eV) makes desorption difficult. Therefore, the Gd@Au15 cluster can be expected to be an excellent gas sensor for NO and NO2 detection.
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702Yadav, B. D.; Kumar, V. Gd@Au15: A magic magnetic gold cluster for cancer therapy and bioimaging. Appl. Phys. Lett. 2010, 97, 133701, DOI: 10.1063/1.3491269Google Scholar702https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht1Wjt7zI&md5=1c2acb9bf255aa0bec7e094fdb95859aGd@Au15: A magic magnetic gold cluster for cancer therapy and bioimagingYadav, Brahm Deo; Kumar, VijayApplied Physics Letters (2010), 97 (13), 133701/1-133701/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The authors report from ab initio calcns. a magic magnetic cage cluster of gold, Gd@Au15, obtained by doping of a Gd atom in gold clusters. It has a HOMO-LUMO gap of 1.31 eV within the generalized gradient approxn. that makes it a potential candidate for cancer therapy with an addnl. attractive feature that its large magnetic moment of 7 μB could be beneficial for magnetic resonance imaging. (c) 2010 American Institute of Physics.
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703Shinde, P. P.; Yadav, B. D.; Kumar, V. Evolution of atomic and electronic structure of magnetic Gd-doped gold clusters. J. Mater. Sci. 2012, 47, 7642– 7652, DOI: 10.1007/s10853-012-6632-7Google Scholar703https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xos12hsbk%253D&md5=2799b15d83a5127fcc080858b715c562Evolution of atomic and electronic structure of magnetic Gd-doped gold clustersShinde, Prashant P.; Yadav, Brahm Deo; Kumar, VijayJournal of Materials Science (2012), 47 (21), 7642-7652CODEN: JMTSAS; ISSN:0022-2461. (Springer)The evolution of at. and electronic structure of small Aun (n = 1-16, and 55) clusters doped with a Gd atom was investigated using a DFT-GGA method. Pure gold neutral clusters with n up to 15 are planar. However, with the doping of a Gd atom, the at. structure of gold clusters changes, and there is a transition from planar-like structures to three dimensional structures at n = 10. The electronic structure of Gd-doped gold clusters shows a sharp increase of the HOMO-LUMO gap for certain sizes giving rise to their magic behavior. All clusters are magnetic with large magnetic moments ranging from 6 to 8 μB primarily due to the localized 4f electrons on Gd. This makes such clusters with large HOMO-LUMO gaps magnetic superatoms. The main interaction between gold and gadolinium atoms in the clusters is due to hybridization between Au-6s and Gd-5d6s orbitals. Our results indicate the emergence of a wheel structure for Gd@Au7, a sym. cage structure at n = 15 for Gd@Au15 and n = 16 for Gd@Au16+ and Eu@Au16 corresponding to an electronic shell closing at 18 valence electrons leaving aside the f electrons on Gd while for Gd-doped Au55 corresponding to 58 valence electrons, a Au9Gd@Au46 core-shell structure is obtained in which the Gd atom connects the core of Au9 with the Au46 shell. The binding energy shows odd-even oscillations with enhancement due to Gd doping compared with pure gold clusters. Such magnetic clusters of gold could have multifunctional biol. applications in drug delivery, sensor, imaging, and cancer treatment.
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704Wang, L.-M.; Bulusu, S.; Zhai, H.-J.; Zeng, X.-C.; Wang, L.-S. Doping golden buckyballs: Cu@Au16- and Cu@Au17- cluster anions. Angew. Chem., Int. Ed. 2007, 46, 2915– 2918, DOI: 10.1002/anie.200700060Google Scholar704https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXkslehurs%253D&md5=7fbb9ee48874fe0f1352cc030c313000Doping golden buckyballs: Cu@Au16- and Cu@Au17- clusterWang, Lei-Ming; Bulusu, Salya; Zhai, Hua-Jin; Zeng, Xiao-Cheng; Wang, Lai-ShengAngewandte Chemie, International Edition (2007), 46 (16), 2915-2918CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Golden cage: The two smallest anionic gold cages, Au16- and Au17- are doped with a Cu atom to give the cluster anions CuAu-16 (see picture) and CuAu-17, resp. The photoelectron spectra of CuAu16- and CuAu17- suggest that the doping does not alter the structures of the parent cages. Theor. studies confirm that the Cu atom resides in the center of the gold cages, similar to the situation with endohedral fullerenes.
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705Wang, L.-M.; Bulusu, S.; Huang, W.; Pal, R.; Wang, L.-S.; Zeng, X. C. Doping the golden cage Au16- with Si, Ge, and Sn. J. Am. Chem. Soc. 2007, 129, 15136– 15137, DOI: 10.1021/ja077465aGoogle Scholar705https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlWmurbM&md5=36136d24f229cd25cfe39c72d10d14b3Doping the Golden Cage Au16- with Si, Ge, and SnWang, Lei-Ming; Bulusu, Satya; Huang, Wei; Pal, Rhitankar; Wang, Lai-Sheng; Zeng, Xiao ChengJournal of the American Chemical Society (2007), 129 (49), 15136-15137CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report a joint PES and theor. study of SiAu16-, GeAu16-, and SnAu16- clusters. We find that their global min. possess exohedral structures, which are dominated by the strong M-Au local interactions reminiscent of the MAu4 clusters. In particular, a dangling Au atom is obsd. in the low-lying isomers of SiAu16- which confirms the Au/H analogy reported earlier in Si-Au mixed clusters. The nature of the dopant-Au local interactions is a crit. factor in detg. whether an impurity atom can be used to dope the golden cages.
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706Wang, L.-M.; Pal, R.; Huang, W.; Zeng, X. C.; Wang, L.-S. Tuning the electronic properties of the golden buckyball by endohedral doping: M@Au16- (M = Ag, Zn, In). J. Chem. Phys. 2009, 130, 051101, DOI: 10.1063/1.3073884Google Scholar706https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1Gjuro%253D&md5=819a89725327b5fd08dcd1db08db40a0Tuning the electronic properties of the golden buckyball by endohedral doping: M@Au16- (M = Ag, Zn, In)Wang, Lei-Ming; Pal, Rhitankar; Huang, Wei; Zeng, Xiao Cheng; Wang, Lai-ShengJournal of Chemical Physics (2009), 130 (5), 051101/1-051101/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The golden Au16- cage was doped by an external atom with different valence electrons: Ag, Zn, and In. The electronic and structural properties of Ag@Au16-, Zn@Au16-, and In@Au16- were investigated by photoelectron spectroscopy and DFT-PBE method. The characteristic spectral features of Au16-, reflecting its near tetrahedral (Td) symmetry, are retained in the photoelectron spectra of MAu16-, suggesting endohedral structures with little distortion from the parent Au16- cage for the doped clusters. D. functional calcns. show that the endohedral structures of M@Au16- with Td symmetry are low-lying structures, which give simulated photoelectron spectra in good agreement with the expt. The dopant atom does not significantly perturb the electronic and at. structures of Au16-, but simply donate its valence electrons to the parent Au16- cage, resulting in a closed-shell 18-electron system for Ag@Au16-, a 19-electron system for Zn@Au16- with a large energy gap, and a 20-electron system for In@Au16-. The current work shows that the electronic properties of the golden buckyball can be systematically tuned through doping. (c) 2009 American Institute of Physics.
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707Wang, L.-M.; Bai, J.; Lechtken, A.; Huang, W.; Schooss, D.; Kappes, M. M.; Zeng, X. C.; Wang, L.-S. Magnetic doping of the golden cage cluster M@Au16- (M = Fe, Co, Ni). Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 79, 033413, DOI: 10.1103/PhysRevB.79.033413Google Scholar707https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlGju7g%253D&md5=43c6f6701846e4a84a92a3a9b950cd2dMagnetic doping of the golden cage cluster M@Au16- (M=Fe,Co,Ni)Wang, Lei-Ming; Bai, Jaeil; Lechtken, Anne; Huang, Wei; Schooss, Detlef; Kappes, Manfred M.; Zeng, Xiao Cheng; Wang, Lai-ShengPhysical Review B: Condensed Matter and Materials Physics (2009), 79 (3), 033413/1-033413/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Structural, electronic, and magnetic properties of the golden cage doped with a transition-metal atom, MAu16- (M=Fe,Co,Ni), are investigated using trapped ion electron diffraction, photoelectron spectroscopy, and d.-functional theory. The best agreement to expt. is obtained for endohedral M@Au16- structures but with considerable distortions to the parent Au16- cage. Fe@Au16- and Co@Au16- are found to have similar structures with C2 symmetry while a C1 structure is obtained for Ni@Au16-. The 4s electrons are obsd. to transfer to the Au16 cage, whereas atomiclike magnetism due to the unpaired 3d electrons is retained for all the doped clusters.
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708Sun, Q.; Wang, Q.; Chen, G.; Jena, P. Structure of SiAu16: Can a silicon atom be stabilized in a gold cage?. J. Chem. Phys. 2007, 127, 214706, DOI: 10.1063/1.2804872Google Scholar708https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsVCjt7%252FP&md5=47aa690147ac34ee381752db3e7db28bStructure of SiAu16: Can a silicon atom be stabilized in a gold cage?Sun, Qiang; Wang, Qian; Chen, Gang; Jena, PuruJournal of Chemical Physics (2007), 127 (21), 214706/1-214706/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Nanostructures of Au and Si as well as Au-Si hybrid structures are topics of great current interest from both scientific and technol. points of view. Recent discovery of Au clusters having fullerenelike geometries and the possibility of endohedral complexes with Si atoms inside the Au cage opens new possibilities for designing Au-Si nanostructures. Using ab initio simulated annealing method we have examd. the stability of Si-Au16 endohedral complex. Contrary to what we believed, we find that the endohedral configuration is metastable and the structure where Si atom binds to the exterior surface of the Au16 cage is the lowest energy structure. The bonding of Si to Au cluster mimics its behavior of that in bulk and liq. phase of Au. In addn., doping of Si in high concn. would cause fracture and embrittlement in gold nanostructures just as it does in the bulk phase. Covalent bonding between Au-Au and Au-Si is found to be a dominant feature in the stability of the Au-Si nanostructures. Our study provides insight that may be useful in fabricating hybrid Au-Si nanostructures for applications microelectronics, catalysis, biomedicine, and jewelry industry.
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709Walter, M.; Hakkinen, H. A hollow tetrahedral cage of hexadecagold dianion provides a robust backbone for a tuneable sub-nanometer oxidation and reduction agent via endohedral doping. Phys. Chem. Chem. Phys. 2006, 8, 5407– 5411, DOI: 10.1039/B612221CGoogle Scholar709https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht1antrfN&md5=fd5774062f6695693648fd6fee19e973A hollow tetrahedral cage of hexadecagold dianion provides a robust backbone for a tuneable sub-nanometer oxidation and reduction agent via endohedral dopingWalter, Michael; Haekkinen, HannuPhysical Chemistry Chemical Physics (2006), 8 (46), 5407-5411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We show, via d. functional theory calcns., that dianionic Au162- cluster has a stable, hollow, Td sym. cage structure, stabilized by 18 delocalized valence electrons. The cage maintains its robust geometry, with a minor Jahn-Teller deformation, over several charge states (q = -1,0, + 1), forming spin doublet, triplet and quadruplet states according to the Hund's rules. Endohedral doping of the Au16 cage by Al or Si yields a geometrically robust, tuneable oxidn. and redn. agent. Si@Au16 is a magic species with 20 delocalized electrons. We calc. a significant binding energy for the anionic Si@Au16/O2- complex and show that the adsorbed O2 is activated to a superoxo-species, a result which is at variance with the exptl. well-documented inertness of Au16- anion towards oxygen uptake.
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710Kaydashev, V. E.; Janssens, E.; Lievens, P. Optical absorption spectra of palladium doped gold cluster cations. J. Chem. Phys. 2015, 142, 034310, DOI: 10.1063/1.4906072Google Scholar710https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlSmu7s%253D&md5=58d5e68ec37cef839f274354db4b40bcOptical absorption spectra of palladium doped gold cluster cationsKaydashev, Vladimir E.; Janssens, Ewald; Lievens, PeterJournal of Chemical Physics (2015), 142 (3), 034310/1-034310/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Photoabsorption spectra of gas phase Aun+ and Aun-1Pd+ (13 ≤ n ≤ 20) clusters were measured using mass spectrometric recording of wavelength dependent Xe messenger atom photodetachment at hν = 1.9-3.4 eV. Pure cationic Au clusters consisting of 15, 17, and 20 atoms have a higher integrated optical absorption cross section than the neighboring sizes. The total optical absorption cross section increases with size and Pd doping strongly reduces this cross section for all studied sizes and in particular for n = 14-17 and 20. The largest redn. of optical absorption upon Pd doping is obsd. for n = 15. (c) 2015 American Institute of Physics.
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711Neukermans, S.; Janssens, E.; Tanaka, H.; Silverans, R. E.; Lievens, P. Element- and size-dependent electron delocalization in AuNX+ clusters (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Phys. Rev. Lett. 2003, 90, 033401, DOI: 10.1103/PhysRevLett.90.033401Google Scholar711https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmsVansw%253D%253D&md5=9f0454442284ab8bc62ba993317b2da2Element- and Size-Dependent Electron Delocalization in AuNX+ Clusters (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni)Neukermans, S.; Janssens, E.; Tanaka, H.; Silverans, R. E.; Lievens, P.Physical Review Letters (2003), 90 (3), 033401/1-033401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We investigated the stability of gold clusters doped with open 3d-shell atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Steps, peaks, and odd-even staggering in mass abundance spectra upon photofragmentation provide evidence for enhanced stability for specific cluster sizes. The obsd. magic nos. are explained in terms of size- and dopant-dependent modifications of the effective mean-field potential within a phenomenol. shell-model approach. Element-dependent 3d electron delocalization and odd-even staggering amplitudes are related to the dopant-atom structure.
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712Bouwen, W.; Vanhoutte, F.; Despa, F.; Bouckaert, S.; Neukermans, S.; Kuhn, L. T.; Weidele, H.; Lievens, P.; Silverans, R. E. Stability effects of AunXm+ (X = Cu, Al, Y, In) clusters. Chem. Phys. Lett. 1999, 314, 227– 233, DOI: 10.1016/S0009-2614(99)01150-1Google Scholar712https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXnsl2ku7w%253D&md5=b9b001dc574c62395f465f58f3dd790eStability effects of AunXm+ (X=Cu, Al, Y, In) clustersBouwen, W.; Vanhoutte, F.; Despa, F.; Bouckaert, S.; Neukermans, S.; Theil Kuhn, L.; Weidele, H.; Lievens, P.; Silverans, R. E.Chemical Physics Letters (1999), 314 (3,4), 227-233CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Bimetallic AunXm clusters (X=Cu, Al, Y, In, n=1-65, m=1 and 2) were produced by a dual-target dual-laser vaporization source. Following multiphoton absorption, the stability patterns resulting from fragmentation were investigated by time-of-flight mass abundance spectrometry. AunCum+ clusters exhibit the same electronic shell effects as Aun+. Different abundance patterns are obsd. for AunAl1+ compared to AunY1+ or AunIn1+. The patterns are related to the magic nos. of the electronic shell model for clusters. The differences between the bimetallic clusters are interpreted in terms of different cluster geometries dependent on the dopant atoms nature.
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713Fa, W.; Dong, J. Structures of MAu16- (M = Ag, Li, Na, and K): How far is the endohedral doping?. J. Chem. Phys. 2008, 128, 144307, DOI: 10.1063/1.2897917Google Scholar713https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1czjtlGhtQ%253D%253D&md5=ea07cc63a15d02dce7467bf8daae370eStructures of MAu16 (-) (M=Ag, Li, Na, and K): how far is the endohedral doping?Fa Wei; Dong JinmingThe Journal of chemical physics (2008), 128 (14), 144307 ISSN:0021-9606.The structural and electronic properties of MAu16 (-) (M=Ag, Li, Na, and K) have been studied by the scalar relativistic all-electron density-functional calculations, in which particular attention is paid to the stability of the endohedral Au16 (-) cage doped by different dopant atoms. It is found that only the smaller atoms, such as Cu, Li, and Na, can be stably encapsulated in the Au16 (-) cage, while the addition of the larger Ag or K atom prefers to locate in the surface or outside of the cage, which is inconsistent with the previous hypothesis that the Au16 (-) cage could act as a container to hold an arbitrary heterometal atom. The stable endohedral Li@Au16 (-) and Na@Au16 (-) have a large energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital gap, indicating that they are chemically stable and may be used as potential building blocks for designing cluster-assembled materials.
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714Fa, W.; Yang, A. Detecting the lowest-energy structures of CAu16q (q = -1, 0). Phys. Lett. A 2008, 372, 6392– 6395, DOI: 10.1016/j.physleta.2008.08.069Google ScholarThere is no corresponding record for this reference.
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715Wang, H.-Q.; Li, H.-F.; Zheng, L.-X. Doping golden cage clusters M@Au16q (M = Cr, Mn; q = 0, -1) with adjustable magnetic properties. J. Magn. Magn. Mater. 2013, 344, 79– 84, DOI: 10.1016/j.jmmm.2013.05.038Google Scholar715https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFWku7vO&md5=f9959f23b831eac9932c2f64068b65a8Doping golden cage clusters M@Au16q (M = Cr, Mn; q = 0, -1) with adjustable magnetic propertiesWang, Huai-Qian; Li, Hui-Fang; Zheng, Li-XinJournal of Magnetism and Magnetic Materials (2013), 344 (), g79-84CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)This work presents a systematic d. functional theory study of the structural, electronic, and magnetic properties of the golden cage doped with a transition-metal atom, M@Au16q (M = Cr, Mn; q = 0, -1). The endohedral structures are always favored. The Cr@Au16- clusters show smaller X-A energy gaps, suggesting that its geometric and electronic structures alter remarkably due to the addn. of Cr atom. However, the characteristics of the Mn@Au-16 species include their remarkably high X-A energy gaps, indicating doping by Mn atom could stabilize the hollow Au16- cage. The magnetic moment of the impurity Mn/Cr atom is slightly quenched.
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716Tang, C.; Zhu, W.; Zhang, A.; Zhang, K.; Liu, M. Endohedrally doping the gold cage Au16- with an trivalent atom B, Al, Ga, and In: Density functional studies. Comput. Theor. Chem. 2013, 1018, 1– 5, DOI: 10.1016/j.comptc.2013.05.032Google Scholar716https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXht1SjtrrP&md5=417546479e5e2801a28e34e00137fbccEndohedrally doping the gold cage Au-16 with an trivalent atom B, Al, Ga, and In: Density functional studiesTang, Chunmei; Zhu, Weihua; Zhang, Aimei; Zhang, Kaixiao; Liu, MingyiComputational & Theoretical Chemistry (2013), 1018 (), 1-5CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The relativistic d. functional calcns. explore that M@Au-16 (M = B, Al, Ga, and In) with M at the cage center, named as M@Au-16-center, should be the most stable. The M@Au-16-center (M = B, Al, Ga, and In) clusters have closed-shell electronic structures and large energy gaps. All of these properties are characteristic of a magic cluster and can be well understood by the jellium model. Therefore, we strongly suggest M@Au-16-center (M = B, Al, Ga, and In) are magic clusters and promising as building blocks in developing cluster-assembled materials. The energy levels and the wavefunctions of frontier orbitals explore that the HOMOs of M@Au-16-center should be partly occupied by the M atom, while the LUMOs of them should be mostly from the Au-16 bodies. The difference charge densities and the natural bonding orbital charge analyses imply the Au-M bonds have both the ionic and covalent characters. Finally, the mean static linear polarizabilities and first-order hyperpolarizabilities of M@Au-16-center are larger than those of Au-16, while their anisotropies of the polarizability tensors are smaller than those of Au-16. We rationalize the nonlinear properties by studying the low-energy optical absorption band obtained by employing time-dependent d. functional theory.
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717Li, H.-F.; Wang, H.-Q. Probing the stability of neutral and anionic transition-metal-doped golden cage nanoclusters: M@Au16 (M = Sc, Ti, V). Phys. Chem. Chem. Phys. 2014, 16, 244– 254, DOI: 10.1039/C3CP53292EGoogle Scholar717https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVGnu7fK&md5=9488742de5420115da9219bce45c281bProbing the stability of neutral and anionic transition-metal-doped golden cage nanoclusters: M@Au16 (M = Sc, Ti, V)Li, Hui-Fang; Wang, Huai-QianPhysical Chemistry Chemical Physics (2014), 16 (1), 244-254CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The golden Au16q (q = 0, -1) cage is doped systematically with an external atom of different valence electrons: Sc, Ti, and V. The structural, electronic, and magnetic properties of the doped clusters, M@Au16q (M = Sc, Ti and V; q = 0, -1) are investigated using the Saunders "Kick" (SK) global search technique combined with d.-functional theory (DFT) calcns. (SK-DFT). It is found that the closeness of the calcd. vertical/adiabatic detachment energy for Ti-doped and V-doped (3.09/3.16 eV for Ti-doped, and 3.31/3.38 eV for V-doped) is consistent with the negligible geometry change between the anionic and neutral ground state structures. The characteristics of the Sc@Au16- cluster includes its remarkably high av. binding energy and doping energy, which reflects its high stability. The different spectral features between doped M@Au16- and pure Au16- clusters indicate endohedral structures with larger distortion from the parent Au16- cage for the doped clusters. The s electrons of the Au16 cage are obsd. to transfer to Sc, Ti and V atom for doped M@Au16q clusters by natural population anal. (NPA). The magnetic moment of the impurity Sc/Ti/V atom is somewhat quenched. Furthermore, the electron localization function anal. does not reveal strong interactions. The current work shows that the electronic properties of the golden cage can be systematically tuned through doping.
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718Liu, J.-X.; Liu, Z.; Filot, I. A. W.; Su, Y.; Tranca, I.; Hensen, E. J. M. CO oxidation on Rh-doped hexadecagold clusters. Catal. Sci. Technol. 2017, 7, 75– 83, DOI: 10.1039/C6CY02277DGoogle Scholar718https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFGjtL3E&md5=440773b749632e11a01ea3e19428eb83CO oxidation on Rh-doped hexadecagold clustersLiu, Jin-Xun; Liu, Zhiling; Filot, Ivo A. W.; Su, Yaqiong; Tranca, Ionut; Hensen, Emiel J. M.Catalysis Science & Technology (2017), 7 (1), 75-83CODEN: CSTAGD; ISSN:2044-4753. (Royal Society of Chemistry)Exploring the unique catalytic properties of gold clusters assocd. with specific nano-architectures is essential for designing improved catalysts with a high mass-specific activity. We investigate the geometric and electronic structure of hexadecagold clusters in which Rh was doped. D. functional theory calcns. demonstrate that the resulting neutral and neg. charged Rh-doped Au16 clusters are stable and bind CO and O2 stronger than Au16. Consequently, activation barriers for CO oxidn. are lowered. Microkinetics simulations predict esp. neg. charged Rh-doped Au16 clusters to exhibit very high CO oxidn. activity, already at sub-ambient temp. Our findings highlight the promise of alloying gold clusters with more reactive transition metals and the importance of charge transfer from the support in heterogeneous gold systems in catalyzing CO oxidn.
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719Li, H.-F.; Wang, H.-Q. Stabilization of golden cages by encapsulation of a single transition metal atom. R. Soc. Open Sci. 2018, 5, 171019, DOI: 10.1098/rsos.171019Google Scholar719https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisV2rsbbK&md5=f227334e4da8312108a6c4d4ce0dc750Stabilization of golden cages by encapsulation of a single transition metal atomLi, Hui-Fang; Wang, Huai-QianRoyal Society Open Science (2018), 5 (1), 171019/1-171019/13CODEN: RSOSAV; ISSN:2054-5703. (Royal Society)Golden cage-doped nanoclusters have attracted great attention in the past decade due to their remarkable electronic, optical and catalytic properties. However, the structures of large golden cage doped with Mo and Tc are still not well known because of the challenges in global structural searches. Here, we report anionic and neutral golden cage doped with a transition metal atom MAu16 (M=Mo and Tc) using Saunders 'Kick' stochastic automation search method assocd. with d.-functional theory (DFT) calcn. (SK-DFT). The geometric structures and electronic properties of the doped clusters, MAu16q (M=Mo and Tc; q=0 and -1), are investigated by means of DFT theor. calcns. Our calcns. confirm that the 4d transition metals Mo and Tc can be stably encapsulated in the Au16- cage, forming three different configurations, i.e. endohedral cages, planar structures and exohedral derivs. The ground-state structures of endohedral cages C2v Mo@Au16- -(a) and C1 Tc@Au16- -(b) exhibit a marked stability, as judged by their high binding energy per atom (greater than 2.46 eV), doping energy (0.29 eV) as well as a large HOMO-LUMO gap (greater than 0.40 eV). The predicted photoelectron spectra should aid in future exptl. characterization of MAu16- (M=Mo and Tc).
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720Tang, C.; Zhu, W.; Zhang, K.; He, X.; Zhu, F. The density functional studies of the doped gold cages Au17M (M = Cu, Ag, Li, Na, K). Comput. Theor. Chem. 2014, 1049, 62– 66, DOI: 10.1016/j.comptc.2014.09.016Google Scholar720https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhs1Kgu7%252FO&md5=3012b2bf4fd28b8f95729b74e55b8517The density functional studies of the doped gold cages Au17M (M = Cu, Ag, Li, Na, K)Tang, Chunmei; Zhu, Weihua; Zhang, Kaixiao; He, Xiang; Zhu, FengComputational & Theoretical Chemistry (2014), 1049 (), 62-66CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The scalar relativistic d. functional studies are performed on the structures, stabilities, electronic properties, and polarizabilities of the Au17M (M = Cu, Ag, Li, Na, K) clusters. The smaller atom Cu(Ag, Li, and Na) can be stably encapsulated in the Au17 cage, while the larger K atom prefers to locate on the outside surface of the cage. Au17M (M = Cu, Ag, Li, Na, K) should be magic clusters and promising as building blocks in developing cluster-assembled materials. We rationalize the nonlinear properties by studying the low-energy optical absorption band obtained by employing time-dependent d. functional theory.
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721Manzoor, D.; Krishnamurty, S.; Pal, S. Endohedrally doped gold nanocages: Efficient catalysts for O2 activation and CO oxidation. Phys. Chem. Chem. Phys. 2016, 18, 7068– 7074, DOI: 10.1039/C5CP05624AGoogle Scholar721https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvVygtrzN&md5=7ecb882a5f1195bc5111376c424a0765Endohedrally doped gold nanocages: efficient catalysts for O2 activation and CO oxidationManzoor, Dar; Krishnamurty, Sailaja; Pal, SouravPhysical Chemistry Chemical Physics (2016), 18 (10), 7068-7074CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Gold nanocages are the most attractive catalytic materials as all the atoms in the cage type clusters reside on the surface, making them available for chemisorption by reacting mols. Due to a hollow space at the center, their chem. and catalytic properties can be tuned effectively and easily by endohedral doping. While a significant exptl. and theor. understanding is currently available on the structural and electronic properties of doped gold cages, very little information is available on their reactivity and catalytic behavior. In the present work, with the help of d. functional theory calcns. we demonstrate that endohedral doping leads to a notable increase in the binding energy of mol. oxygen on the gold nanocages. The enhancement in the O2 binding energy on the doped gold cages is also confirmed by a significant decrease in the Au-O and an increase in the O-O bond lengths, corroborated by a red shift (∼250 cm-1) in the O-O stretching frequency as compared to the pristine cage. Furthermore, interestingly, the doped gold cages show very low activation barriers for the environmentally important CO oxidn. reaction as compared to the pristine gold cage. Importantly, the decrease in the barrier height is comparatively greater for the rate limiting step of O-O-C-O intermediate formation and as a result the CO oxidn. is expected to be more facile on the doped gold cages. Thus, the current study highlights the role of heteroatom doping in imparting new chem. and catalytic properties to gold cages and is expected to spur further research in the design of efficient gold nanocatalysts.
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722Zorriasatein, S.; Joshi, K.; Kanhere, D. G. Electronic and structural investigations of gold clusters doped with copper: Aun-1Cu- (n = 13-19). J. Chem. Phys. 2008, 128, 184314, DOI: 10.1063/1.2913153Google Scholar722https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtVCrtrk%253D&md5=46c7b123b4798b7c7535299b632b5bd4Electronic and structural investigations of gold clusters doped with copper: Aun-1Cu- (n=13-19)Zorriasatein, Shahab; Joshi, Kavita; Kanhere, D. G.Journal of Chemical Physics (2008), 128 (18), 184314/1-184314/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We have obtained the ground state and the equil. geometries of Aun- and Aun-1Cu- in the size range of n=13-19. We have used first principles d. functional theory within plane wave and Gaussian basis set methods. For each of the cluster we have obtained at least 100 distinct isomers. The anions of gold clusters undergo two structural transformations, the first one from flat cage to hollow cage and the second one from hollow cage to pyramidal structure. The Cu doped clusters do not show any flat cage structures as the ground state. The copper doped systems evolve from a general 3D structure to hollow cage with Cu trapped inside the cage at n=16 and then to pyramidal structure at n=19. The introduction of copper atom enhances the binding energy per atom as compared to gold cluster anions. (c) 2008 American Institute of Physics.
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723Jayasekharan, T.; Ghanty, T. K. Endohedrally doped golden fullerenes X@Au32 (X = Li+, Na+, K+, Rb+, Cs+). J. Phys. Chem. C 2010, 114, 8787– 8793, DOI: 10.1021/jp100705zGoogle Scholar723https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXltVynt7Y%253D&md5=0c357095a3b0fa0e5a877d81341ad5a0Endohedrally Doped Golden Fullerenes [X@Au32] (X = Li+, Na+, K+, Rb+, Cs+)Jayasekharan, T.; Ghanty, T. K.Journal of Physical Chemistry C (2010), 114 (19), 8787-8793CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structure, stability, energy partition anal., and charge redistribution of endohedral complexes formed between Au32 cluster with alkali metal cations, such as Li+, Na+, K+, Rb+, and Cs+, have been investigated using the d. functional theory method. All alkali metal cations can be stably encapsulated in both the Ih and the Cs symmetry structural forms [Ih-(X@Au32)+ and Cs-(X@Au32)+]. Smaller cations are found to be more stable in the Cs symmetry structure. A higher charge-transfer characteristic is noted when the Au32 cage is encapsulated with smaller-sized alkali ions than larger-sized ions in both the structures. Vibrational frequency calcn. data show imaginary frequency values for Li+ and Na+ ions in the Ih-(X@Au32) system, which indicates the free movements of these ions in the cage, whereas all dopant ions show pos. IR frequency values for Cs-(X@Au32), suggesting the existence of weak bonding between dopants and the cage. The anal. of structural, energetic, and charge-transfer data indicates that the K+, Rb+, and Cs+ dopant ions occupy the central position of the Au32 cage and retain the Ih sym. structure of the Au32 cluster, whereas the smaller-sized Li+ and Na+ occupy the off-center site and are more stable in Cs-(X@Au32). Morokuma-type energy decompn. anal. data indicate a significantly higher Pauli repulsion energy with Li+ and Na+ dopants in the Cs-(X@Au32) structure than in the Ih-(X@Au32) structure; however, for other dopant ions, this interaction is almost the same for both Ih and Cs structures. A similar trend is reflected in the variation in the orbital interaction energy term, which is considerably higher for Li+ and Na+ ions in the Cs structure and is almost the same for other ions in the Cs and Ih structures. From the charge-transfer data, a halogen-like behavior of Au32 is noted when the cluster is doped with the Cs+ ion, which is rather unusual. Thus, encapsulation of larger cations, such as K+, Rb+, and Cs+, into the Au32 fullerene may be one of the possible ways of detecting the elusive Ih structure of Au32 by mass spectrometry.
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724Manna, D.; Jayasekharan, T.; Ghanty, T. K. Structure and stability of Zn, Cd, and Hg atom doped golden fullerene (Au32). J. Phys. Chem. C 2013, 117, 18777– 18788, DOI: 10.1021/jp407089uGoogle Scholar724https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXht1CqtbnO&md5=52dd19cdffa6812c853035265b934e2eStructure and Stability of Zn, Cd, and Hg Atom Doped Golden Fullerene (Au32)Manna, Debashree; Jayasekharan, T.; Ghanty, Tapan K.Journal of Physical Chemistry C (2013), 117 (36), 18777-18788CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Structures and properties of various complexes formed between the "golden fullerene", Au32, and group IIB atoms such as Zn, Cd, and Hg were investigated using d. functional theory. Binding energy values indicate that the group IIB atoms can form stable clusters in most of the different isomeric forms of the Au32 cage. The HOMO-LUMO gap of the Au32 cage remains almost the same even after doping of Zn, Cd, and Hg atoms for high symmetry clusters, while it decreases for the low symmetry isomers. The highest stable isomer for the Hg-doped Au32 cluster is found to be assocd. with Ih symmetry with a large energy difference from the other low symmetry isomers, using generalized gradient approxn. (GGA) type functionals. However, for the Zn and Cd encapsulated Au32 clusters, the highest stable structures are of Cs[1] and C5v symmetry, resp., along with one low symmetry isomer for each of them, having energy very close to the resp. most stable isomer. Nevertheless, depending on the energy d. functional, the relative energy orderings for the various isomers are found to be modified strongly. In fact, the meta-GGA TPSS functional predicts low symmetry compact isomers to be more stable for all the metal atom doped Au32 clusters. Moreover, low symmetry compact isomers are found to be more stable with the dispersion-cor. GGA type PBE functional for the Zn- and Cd-doped cluster, in agreement with the TPSS results; however, the same dispersion correction fails to reproduce the TPSS results for the Hg-doped Au32 system. Structural data, energetic parameters, and spectral anal. point toward the possible exptl. observation of group IIB atom doped golden fullerene, which in turn might help to understand the nature of interactions between the metal atom and the Au32 cage. Furthermore, exptl. investigations would likely confirm the predictive ability of the different functionals used in this work.
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725Kumar, V. Coating of a layer of Au on Al13: The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 79, 085423, DOI: 10.1103/PhysRevB.79.085423Google Scholar725https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXisFKgtrg%253D&md5=4738bffa8ce1a48687d3cfa3d80677bcCoating of a layer of Au on Al13: The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculationsKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2009), 79 (8), 085423/1-085423/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We report results of ab initio pseudopotential calcns. on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally sym. endohedral Al@Al12Au20- and empty cage Al12Au202- compd. fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compd. fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, resp., which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.
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726Wang, Q.; Sun, Q.; Jena, P. Stabilizing a 22 karat nanogolden cage. J. Chem. Phys. 2009, 131, 204501, DOI: 10.1063/1.3266562Google Scholar726https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsV2itLfL&md5=52cd2e84094b32585bf1a1583b34df7dStabilizing a 22 karat nanogolden cageWang, Q.; Sun, Q.; Jena, P.Journal of Chemical Physics (2009), 131 (20), 204501/1-204501/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Since the discovery of C60 fullerene, considerable efforts have been devoted to find other elements with similar hollow cage structures. However, search for hollow metallic cages with a diam. similar to that of C60 fullerene has been elusive. We describe a procedure for the rational design of metallic cages by suitably choosing their size, compn., and charge state. A 22 karat nanogolden cage with a diam. of about 8.5 Å and consisting of 12 Al and 20 Au atoms is found to be metastable, which can be stabilized by embedding a Mn4 cluster. In contrast to bulk Mn, which is antiferromagnetic, and isolated Mn4 cluster, which is ferromagnetic with a giant magnetic moment of 20μB, the Mn4@Al12Au20 endohedral complex exhibits magnetic bistability with 0μB and 14μB configurations being energetically nearly degenerate. These results, based on d. functional theory, open the door to design a novel class of endohedral complexes with possible applications. (c) 2009 American Institute of Physics.
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727Tian, D.; Zhang, H.; Zhao, J. Structure and structural evolution of Agn (n = 3-22) clusters using a genetic algorithm and density functional theory method. Solid State Commun. 2007, 144, 174– 179, DOI: 10.1016/j.ssc.2007.05.020Google Scholar727https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtVOkur%252FE&md5=79f56f45edd0df4a7ee1e9cff444d03fStructure and structural evolution of Agn (n = 3-22) clusters using a genetic algorithm and density functional theory methodTian, Dongxu; Zhang, Hualei; Zhao, JijunSolid State Communications (2007), 144 (3-4), 174-179CODEN: SSCOA4; ISSN:0038-1098. (Elsevier Ltd.)Using a genetic algorithm followed by local optimization with d. functional theory, the lowest-energy structures of Agn clusters in a size range of n = 3-22 were studied. The Agn (n = 9-16) clusters prefer compact structures of flat shape, while the Agn (n = 19, 21, 22) clusters adopt amorphous packing based on a 13-atom icosahedral core. For Ag16, two competitive candidates for the lowest-energy structures, namely a hollow-cage structure and close-packed structures of flat shape, were found. Two competing candidates were found for Ag17 and Ag18: hollow-cage structures vs. icosahedron-based compact structures. The lowest-energy structure of Ag20 is a highly sym. tetrahedron with Td symmetry. These results are significantly different from those predicted in earlier works using empirical methods. The ionization potentials and electron affinities for the lowest-energy structures of Agn (n = 3-22) clusters were computed and compared with exptl. values.
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728Weis, P.; Bierweiler, T.; Gilb, S.; Kappes, M. M. Structures of small silver cluster cations (Agn+, n < 12): Ion mobility measurements versus density functional and MP2 calculations. Chem. Phys. Lett. 2002, 355, 355– 364, DOI: 10.1016/S0009-2614(02)00277-4Google Scholar728https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjslWisrs%253D&md5=423c7bec17dc4c0893c84848a31783cbStructures of small silver cluster cations (Agn+, n < 12): ion mobility measurements versus density functional and MP2 calculationsWeis, Patrick; Bierweiler, Thomas; Gilb, Stefan; Kappes, Manfred M.Chemical Physics Letters (2002), 355 (3,4), 355-364CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)We have performed ion mobility measurements on silver cluster cations Agn+ generated by pulsed laser vaporization. For clusters with n < 12, exptl. cross-sections are compared with theor. results from d. functional and MP2 (Moller-Plesset) calcns. This comparison allows structural assignment. We find that room temp. silver cluster cations have planar structures for n = 3-4. Starting at n = 5 they form three dimensional structures. The structures are compared with predictions by Bonacic-Koutecky et al. and the resp. results obtained in a previous study for gold clusters.
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729Janssens, E.; Neukermans, S.; Nguyen, H. M. T.; Nguyen, M. T.; Lievens, P. Quenching of the magnetic moment of a transition metal dopant in silver clusters. Phys. Rev. Lett. 2005, 94, 113401, DOI: 10.1103/PhysRevLett.94.113401Google Scholar729https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXisl2lt7c%253D&md5=2a7ed0a47013d3de47eafc28019156beQuenching of the Magnetic Moment of a Transition Metal Dopant in Silver ClustersJanssens, E.; Neukermans, S.; Nguyen, H. M. T.; Nguyen, M. T.; Lievens, P.Physical Review Letters (2005), 94 (11), 113401/1-113401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Single magnetic atoms embedded in a nonmagnetic host exhibit the Kondo effect in the bulk limit, while in very small mols. the magnetic atom is hardly affected by the matrix. In a combined theor. (d. functional theory) and exptl. (photofragmentation and mass spectrometry) study the authors consider the intermediate case of nanometer sized transition-metal-doped silver clusters. In particular, the authors provide exptl. evidence for enhanced stability of the cobalt-doped silver cluster Ag10Co+ and show theor. that it has a sym. endohedral geometry with a closed 18-electron singlet electronic shell structure. This implies that the magnetic moment on the cobalt atom is quenched.
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730Janssens, E.; Neukermans, S.; Wang, X.; Veldeman, N.; Silverans, R. E.; Lievens, P. Stability patterns of transition metal doped silver clusters: Dopant- and size-dependent electron delocalization. Eur. Phys. J. D 2005, 34, 23– 27, DOI: 10.1140/epjd/e2005-00106-9Google Scholar730https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtFOru7w%253D&md5=1192a7a41d56f1e8efa301aeb07ebaf0Stability patterns of transition metal doped silver clusters: Dopant- and size-dependent electron delocalizationJanssens, E.; Neukermans, S.; Wang, X.; Veldeman, N.; Silverans, R. E.; Lievens, P.European Physical Journal D: Atomic, Molecular and Optical Physics (2005), 34 (1-3), 23-27CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)The stability of cationic silver clusters doped with a 3d transition metal atom (Sc, Ti, V, Cr, Mn, Ni, Cu) is investigated by mass spectrometric anal. of fragments resulting from high fluence irradn. of a cluster beam. The mass spectra show enhanced stabilities that correspond to closed shells of valence electrons. Dopant- and size-dependent delocalization of 4s and 3d electrons is discussed based on spherical shell model considerations. Contrary to doped gold clusters, no evidence was found for the existence of 2D electronic shell closures.
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731Janssens, E.; Van Hoof, T.; Veldeman, N.; Neukermans, S.; Hou, M.; Lievens, P. Mass spectrometric and modeling investigations of bimetallic silver-cobalt clusters. Int. J. Mass Spectrom. 2006, 252, 38– 46, DOI: 10.1016/j.ijms.2006.01.009Google Scholar731https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xjsl2qsbg%253D&md5=0092473566b504355a6b5fafdc9e4b25Mass spectrometric and modeling investigations of bimetallic silver-cobalt clustersJanssens, Ewald; Van Hoof, Thibaut; Veldeman, Nele; Neukermans, Sven; Hou, Marc; Lievens, PeterInternational Journal of Mass Spectrometry (2006), 252 (1), 38-46CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)The stability of bimetallic Ag-Co clusters with <50 atoms is studied exptl. and their assocd. geometries are predicted by classical modeling. The clusters are created by laser vaporization and inert gas condensation. Their mass distribution is analyzed with time-of-flight mass spectrometry. For clusters contg. mainly Ag, strong quantum size effects related to itinerant behavior of the Ag and Co valence electrons were found. In the case of clusters contg. mainly Co, no pronounced size effects appear in the mass spectra. Photofragmentation expts. reveal that neutral Ag atom evapn. is the favorable channel, suggesting that the Ag-Co bonds are weaker than the Co-Co bonds. Consistently, and for both sets of clusters, Metropolis Monte-Carlo simulations predict these clusters to have icosahedral based structures that may depend on temp. In clusters contg. mainly Ag, Co sits at the cluster center and fragmentation proceeds by the evapn. of Ag surface atoms. In clusters contg. mainly Co, Ag atoms also locate at the periphery and are more weakly bound to the cluster than Co surface atoms.
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732Tono, K.; Terasaki, A.; Ohta, T.; Kondow, T. Photoelectron spectroscopy and density-functional calculations of silver cluster anions doped with a cobalt atom: Size dependent sp-d interaction. Chem. Phys. Lett. 2007, 449, 276– 281, DOI: 10.1016/j.cplett.2007.10.077Google Scholar732https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlOmt7%252FF&md5=951229d52c9b41c3071a5485b4f2b46aPhotoelectron spectroscopy and density-functional calculations of silver cluster anions doped with a cobalt atom: Size dependent sp-d interactionTono, Kensuke; Terasaki, Akira; Ohta, Toshiaki; Kondow, TamotsuChemical Physics Letters (2007), 449 (4-6), 276-281CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Electronic structures of AgnCo- (n = 6-8) were investigated by photoelectron spectroscopy and d.-functional calcns. The local spin magnetic moments on Co were found to be 2.04, 1.48, and 0 μB for n = 6, 7, and 8, resp. A strong sp-d interaction in n = 8 allows the Co 3d orbitals to form a closed electronic shell, whereas the Co 3d shells in n = 6 and 7 remain open with finite spins under a weak sp-d interaction. The present result demonstrates significant size dependence of an sp-d interaction in a metal cluster contg. a magnetic impurity.
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733Rodriguez-Kessler, P. L.; Rodriguez-Dominguez, A. R. Structural, electronic, and magnetic properties of AgnCo (n = 1-9) clusters: A first-principles study. Comput. Theor. Chem. 2015, 1066, 55– 61, DOI: 10.1016/j.comptc.2015.05.009Google Scholar733https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXptFGhurw%253D&md5=7444f07941f938c6902b7d7d4f59a626Structural, electronic, and magnetic properties of AgnCo (n = 1-9) clusters: A first-principles studyRodriguez-Kessler, P. L.; Rodriguez-Dominguez, A. R.Computational & Theoretical Chemistry (2015), 1066 (), 55-61CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)Structural, electronic and magnetic properties of neutral AgnCo (n = 1 - 9) clusters are studied using first principles calcns. based on d. functional theory. For the ground state structures of the AgnCo clusters, the Co impurity occupies the highest coordinated position. The lowest energy structures for AgnCo (n≤4) clusters are planar, while from n = 5 onwards, AgnCo clusters showed an icosahedral growth except for Ag9Co, which adopts an endohedral cage structure. The stability based on the binding energy showed that AgnCo clusters are energetically favored for the high spin configuration, however, from n = 7 onwards, trends to adopt the low spin or non-magnetic configurations are obsd. Interestingly, in Ag9Co the silver host quenches the magnetic moment of the encapsulated Co atom. The magnetic orderings between the impurity and the Agn host in AgnCo clusters are discussed.
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734Zhang, M.; Gu, X.-Y.; Zhang, W.-L.; Zhao, L.-N.; He, L.-M.; Luo, Y.-H. Probing the magnetic and structural properties of the 3d, 4d, 5d impurities encapsulated in an icosahedral Ag12 cage. Phys. B 2010, 405, 642– 648, DOI: 10.1016/j.physb.2009.09.080Google Scholar734https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVyqt7bK&md5=49fb12ffc5f9f377e74c704dd3911ac4Probing the magnetic and structural properties of the 3d, 4d, 5d impurities encapsulated in an icosahedral Ag12 cageZhang, Meng; Gu, Xiao-Yan; Zhang, Wen-Li; Zhao, Li-Na; He, Li-Ming; Luo, You-HuaPhysica B: Condensed Matter (Amsterdam, Netherlands) (2010), 405 (2), 642-648CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)The geometries, electronic, and magnetic properties of the 3d, 4d, 5d impurities encapsulated in an icosahedral Ag12 cage have been systematically investigated by using relativistic all-electron d. functional theory with generalized gradient approxn. The general features of the properties of 3d, 4d, 5d transition-metal atoms doped Ag12 clusters are probed and compared. It is found that the most stable structure for all M@Ag12 clusters (M=3d, 4d and 5d transition-metal atoms) is the icosahedral structure with Ih symmetries, in which the transition-metal atom is located in the center of the Ag12 cage. All doped clusters show larger relative binding energies compared with pure icosahedral Ag13 cluster, indicating that doping by 3d, 4d, 5d transition-metal atoms could stabilize the Ag12 icosahedron and form a new binary alloy cluster. The calcn. of the magnetic properties demonstrates that the magnetic moments of M@Ag12 clusters vary from 0 to 4μB by doping different transition-metal atom into Ag12 icosahedron, suggesting that the transition-metal-doped Ag12 clusters could have potential utility in new nanomaterials as building blocks with tunable magnetic properties.
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735Gong, X.; Ju, W.; Li, T.; Feng, Z.; Wang, Y. Spin-orbit splitting and magnetism of icosahedral M@Ag12 clusters (M = 3d and 4d atoms). J. Cluster Sci. 2015, 26, 759– 773, DOI: 10.1007/s10876-014-0737-xGoogle Scholar735https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXovFCntro%253D&md5=b32a3757105ea351928fc7e54aa9b371Spin-orbit splitting and magnetism of icosahedral M@Ag12 clusters (M = 3d and 4d atoms)Gong, Xiaoyang; Ju, Weiwei; Li, Tongwei; Feng, Zhenjie; Wang, YangJournal of Cluster Science (2015), 26 (3), 759-773CODEN: JCSCEB; ISSN:1040-7278. (Springer)The spin-orbit splitting and magnetism of a single 3d, 4d impurity (Sc-Zn, Y-Cd) encapsulated in an icosahedral Ag12 cage (M@Ag12) are explored by methods based on d. functional theory. The large spin-orbit splittings of HOMO levels can be found in the clusters with heavy impurities in each series, esp. for 4d case. The total and local spin magnetic moments of 3d series are hardly affected by spin-orbit coupling (SOC). The similar scenario can take place for the 1st clusters of 4d series (Y-Mo@Ag12). For Tc-Pd@Ag12, the total and local spin magnetic moments remarkably decrease when SOC is considered. The magnetism of Ag@Ag12 and Cd@Ag12 hardly changes when the SOC is included despite large at. no. of the centric Ag and Cd, which can be ascribed to the closed d orbitals of Ag and Cd atoms. The densities of states of some typical clusters and orbital components for HOMO levels of all clusters were calcd. to understand these phenomena. The calcd. spin and orbital magnetic moments can be comprehended in accordance with the Hund's rule of superatom model. The closed-shell electron configuration is formed in Mo@Ag12 cluster according to 18-electron rule, quenching both its spin and orbital moments.
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736Sun, Q.; Wang, Q.; Yu, J. Z.; Li, Z. Q.; Wang, J. T.; Kawazoe, Y. Local magnetism of 3d and 4d impurities in Ag and Pd clusters. J. Phys. I 1997, 7, 1233– 1244, DOI: 10.1051/jp1:1997120Google Scholar736https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXnsVOjsbw%253D&md5=a51da5b599086a5c22da2a67a01c4061Local magnetism of 3d and 4d impurities in Ag and Pd clustersSun, Q.; Wang, Q.; Yu, J.Z.; Li, Z.Q.; Wang, J.T.; Kawazoe, Y.Journal de Physique I (1997), 7 (10), 1233-1244CODEN: JPGCE8; ISSN:1155-4304. (Editions de Physique)The local magnetic properties of Ag12TM and Pd12TM clusters with Ih symmetry (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh, and Pd) were systematically studied with the d. functional formalism, and the Kohn-Sham equation is solved self-consistently with the discrete variational method (DVM). A special attention is paid to the comparisons of local magnetism for impurities in Ag and Pd clusters with those in the bulk and on the (001) surface of Ag (Pd), the behavior of local moments in the Ag12 cluster is more complex than the one of a single impurity in bulk Ag and on the Ag(001)surface, whereas the local moments in Pd12 display very similar features as the ones of a single impurity in bulk Pd and on the Pd(001) surface. To better understand these results, the roles of interactions between impurity and host atoms on the local moment of impurities are explored: the interactions of impurity-d with Ag-d orbitals have important contributions to the local magnetic moments for impurities with less than half-filled d shell, such as Sc, Ti, V, Y, Zr and Nb, but have minor roles on the local magnetic moments for impurities Cr, Mn, Fe, Co, Ni, Tc, Ru and Rh. However, in the Pd12 cluster, d-d interactions between impurity and host have major roles on all the 3d and 4d impurities. Based on the interaction point of view, explanations are presented for the similarities and differences of monument behavior in the cluster, in the bulk and on the surface. The comparison of the obtained results with those in the Cu12 cluster is also made. This study would provide more comprehensive understandings on the local magnetism of 3d and 4d impurities in different environments.
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737Harb, M.; Rabilloud, F.; Simon, D. Structural, electronic, magnetic and optical properties of icosahedral silver-nickel nanoclusters. Phys. Chem. Chem. Phys. 2010, 12, 4246– 4254, DOI: 10.1039/b912971eGoogle Scholar737https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXksVCrurc%253D&md5=195b006c56e29959f30c1d27b94fafd0Structural, electronic, magnetic and optical properties of icosahedral silver-nickel nanoclustersHarb, Moussab; Rabilloud, Franck; Simon, DanielPhysical Chemistry Chemical Physics (2010), 12 (16), 4246-4254CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The authors present a systematic study of the structural, electronic, magnetic and optical properties of icosahedral bimetallic Ag(13-p)Nip (p ≤ 6) clusters in the gas phase studied in the framework of d. functional theory (DFT and TDDFT). In the most-stable structures, the central position is occupied by a nickel atom. The evolution of spin-multiplicities and local at. spin densities with Ag/Ni compn. are discussed. The evolution of the optical properties with the Ag/Ni compn. and the spatial positions of Ni atoms are analyzed. An interpretation of spectroscopic patterns in terms of contribution from s- and d-type excitations is also given. In particular the d-electrons of nickel atoms play a crucial role in the optical transitions of Ni-rich systems. Finally, the theor. spectra are compared to the exptl. ones for large Ni-core/Ag-shell clusters (∼2-5 nm in size).
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738Medel, V. M.; Reber, A. C.; Chauhan, V.; Sen, P.; Koester, A. M.; Calaminici, P.; Khanna, S. N. Nature of valence transition and spin moment in AgnV+ clusters. J. Am. Chem. Soc. 2014, 136, 8229– 8236, DOI: 10.1021/ja412064cGoogle Scholar738https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXotVahu7g%253D&md5=80cdc4373cd2de935c68ededb9cf0ac4Nature of Valence Transition and Spin Moment in AgnV+ ClustersMedel, Victor M.; Reber, Arthur C.; Chauhan, Vikas; Sen, Prasenjit; Koster, Andreas M.; Calaminici, Patrizia; Khanna, Shiv N.Journal of the American Chemical Society (2014), 136 (23), 8229-8236CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Evolution in the at. structure, bonding characteristics, stability, and the spin magnetic moment of neutral and cationic AgnV (n = 4-15) clusters were investigated using first-principles DFT-GGA-PW86 method. It is shown that at small sizes, the V 4s states hybridize with Ag states to form 1S and 1P like superat. orbitals, whereas the 3d states are localized on V giving the V atom an effective valence of 1 or 2. Starting from Ag8V+, the V 3d states begin to participate in the bonding by hybridizing with the nearly free electron gas to form 1D superat. orbitals increasing the V atom effective valence toward 5. For the cationic clusters, this changing valence results in three shell closures that lead to stable species. These occur for cationic clusters contg. 5, 7, and 14 Ag atoms. The first two stable species correspond to filled 1S and 1P shells in two and three dimensions with a valence of 2 for V, whereas the closure at 14 Ag atoms correspond to filled 1S, 1P, and 1D shells with V site exhibiting a valence of 5. The transition from filled 1S and 1P shells to filled 1S, 1P, and 1D shells is confirmed by a quenching of the spin magnetic moment. The theor. findings are consistent with the obsd. drops in intensity in the mass spectrum of AgnV+ clusters after 5, 7, and 14 Ag atoms.
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739Xiong, R.; Die, D.; Xiao, L.; Xu, Y. G.; Shen, X. Y. Probing the structural, electronic, and magnetic properties of AgnV (n = 1-12) clusters. Nanoscale Res. Lett. 2017, 12, 625, DOI: 10.1186/s11671-017-2394-0Google Scholar739https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MzitFGmtg%253D%253D&md5=e894f33ed852f0025eed3218ab714ae2Probing the Structural, Electronic, and Magnetic Properties of Ag n V (n = 1-12) ClustersXiong Ran; Die Dong; Xiao Lu; Xu Yong-Gen; Shen Xu-YingNanoscale research letters (2017), 12 (1), 625 ISSN:1931-7573.The structural, electronic, and magnetic properties of Ag n V (n = 1-12) clusters have been studied using density functional theory and CALYPSO structure searching method. Geometry optimizations manifest that a vanadium atom in low-energy AgnV clusters favors the most highly coordinated location. The substitution of one V atom for an Ag atom in Ag n + 1 (n ≥ 5) cluster modifies the lowest energy structure of the host cluster. The infrared spectra, Raman spectra, and photoelectron spectra of Ag n V (n = 1-12) clusters are simulated and can be used to determine the most stable structure in the future. The relative stability, dissociation channel, and chemical activity of the ground states are analyzed through atomic averaged binding energy, dissociation energy, and energy gap. It is found that V atom can improve the stability of the host cluster, Ag2 excepted. The most possible dissociation channels are Ag n V = Ag + Ag n - 1V for n = 1 and 4-12 and Ag n V = Ag2 + Ag n - 2V for n = 2 and 3. The energy gap of Ag n V cluster with odd n is much smaller than that of Ag n + 1 cluster. Analyses of magnetic property indicate that the total magnetic moment of Ag n V cluster mostly comes from V atom and varies from 1 to 5 μ B. The charge transfer between V and Ag atoms should be responsible for the change of magnetic moment.
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740Dong, R.; Chen, X.; Zhao, H.; Wang, X.; Shu, H.; Ding, Z.; Wei, L. Structural, electronic and magnetic properties of AgnFe clusters (n ⩽ 15): Local magnetic moment interacting with delocalized electrons. J. Phys. B: At., Mol. Opt. Phys. 2011, 44, 035102, DOI: 10.1088/0953-4075/44/3/035102Google Scholar740https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXktlyksbk%253D&md5=9e2a216f17cfe961775fc98d69a0c84aStructural, electronic and magnetic properties of AgnFe clusters (n ≤ 15): local magnetic moment interacting with delocalized electronsDong, Ruibin; Chen, Xiaoshuang; Zhao, Huxian; Wang, Xiaofang; Shu, Haibo; Ding, Zonglin; Wei, LuJournal of Physics B: Atomic, Molecular and Optical Physics (2011), 44 (3), 035102/1-035102/7CODEN: JPAPEH; ISSN:0953-4075. (Institute of Physics Publishing)The size-dependent electronic, structural and magnetic properties of AgnFe (n ≤ 15) clusters were studied by using the d. functional theory (DFT) within the generalized gradient approxn. The starting structures were generated from empirical genetic algorithm simulations. The most stable structures were then selected from a no. of structural isomers based on the results of the further DFT calcns. The Fe atom prefers to stay at the center of the clusters. The 2-dimensional to 3-dimensional transition occurs at n = 6. The magnetic properties and the geometric structures are strongly correlated. For Ag10Fe, the total magnetic moment of the cluster is quenched. The reason is similar to the Kondo effect in bulk metal. Also, Ag10Fe is considered to be very stable according to the 18-electron counting rule.
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741Rodríguez-Kessler, P. L.; Pan, S.; Florez, E.; Cabellos, J. L.; Merino, G. Structural evolution of the rhodium-doped silver clusters AgnRh (n ≤ 15) and their reactivity toward NO. J. Phys. Chem. C 2017, 121, 19420– 19427, DOI: 10.1021/acs.jpcc.7b05048Google Scholar741https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtlWnsL%252FN&md5=6eca9b064eca13877cdc21536eafa1b5Structural Evolution of the Rhodium-Doped Silver Clusters AgnRh (n ≤ 15) and Their Reactivity toward NORodriguez-Kessler, P. L.; Pan, Sudip; Florez, Elizabeth; Cabellos, Jose Luis; Merino, GabrielJournal of Physical Chemistry C (2017), 121 (35), 19420-19427CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Structural properties of AgnRh (n ≤ 15) clusters are investigated using a successive growth algorithm coupled with d. functional theory computations. The structures of the clusters are revisited, including a detailed discussion of their electronic properties. In contrast to these previous contributions, the lowest energy structures of the clusters are planar for n = 3-6, while three-dimensional for n = 7 onward. Our present searches identify new lowest energy structures for n = 3-6 and 9-13. The most stable isomers are selected to study the adsorption of NO. The size-dependent reactivity of the clusters indicates that Rh atom acts as a more effective adsorption site for NO than Ag. Since the transition from Rh-exposed to Rh-encapsulated structures occurs at n = 9, the reactivity toward NO for AgnRh clusters with n ≤ 8 is considerably higher than that for the larger homologues. Doping of Agn clusters with Rh increases the reactivity toward NO adsorption.
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742Xiong, R.; Die, D.; Xu, Y.-G.; Zheng, B.-X.; Fu, Y.-C. Probing the structural, electronic and magnetic properties of AgnSc (n = 1-16) clusters. Phys. Chem. Chem. Phys. 2018, 20, 15824– 15834, DOI: 10.1039/C8CP02605JGoogle Scholar742https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXpslaqtLY%253D&md5=efd0cefb1f15b65793a2ff8984fe3f1dProbing the structural, electronic and magnetic properties of AgnSc (n = 1-16) clustersXiong, Ran; Die, Dong; Xu, Yong-Gen; Zheng, Ben-Xia; Fu, Yao-ChunPhysical Chemistry Chemical Physics (2018), 20 (23), 15824-15834CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structural, electronic and magnetic properties of AgnSc (n = 1-16) clusters have been studied on the basis of d. functional theory and the CALYPSO structure prediction method. The optimized geometry exhibits that the growth process of Sc-doped silver clusters have a periodic structural change. The Ag atom grows around a basically invariant cluster core in each growth cycle. The Sc atom has a tendency to occupy the most highly coordinated position in the ground state. The IR spectra, Raman spectra and photoelectron spectra of AgnSc clusters are forecasted and can be used to identify the structures of these clusters from expts. The global maxima of the dissocn. energy, the averaged binding energy and the gap of the energy level occur at n = 15 for the most stable AgnSc clusters, implying that the Ag15Sc can be perceived as a superatom. The magnetism anal. indicates that the magnetic moment of the Sc atom in AgnSc clusters decreases with the increase of the cluster. The change of the magnetic moment is proportional to the charge transfer between the Sc and Ag atoms.
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743Gao, Y.; Jiang, W.; Chen, L.; Wang, J.; Wang, Z. First-principles study on charge transfer in an actinide-containing superatom from surface-enhanced Raman scattering. J. Mater. Chem. C 2017, 5, 803– 806, DOI: 10.1039/C6TC04865JGoogle Scholar743https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFahtLjJ&md5=4c3ce9a5f097c7e0201d32ac84d5c61bFirst-principles study on charge transfer in an actinide-containing superatom from surface-enhanced Raman scatteringGao, Yang; Jiang, Wanrun; Chen, Lei; Wang, Jia; Wang, ZhigangJournal of Materials Chemistry C: Materials for Optical and Electronic Devices (2017), 5 (4), 803-806CODEN: JMCCCX; ISSN:2050-7534. (Royal Society of Chemistry)The 5f-element-contg. clusters, An@Ag14 (An = Ac-, Th, Pa+), can be viewed as superat. systems (1S21P61D10). Taking them to be the surface-enhanced Raman scattering (SERS) substrates, the charge-transfer states (1Dmetal → π*pyridine) can lead to SERS signal enhancement ∼104 for pyridine-Th@Ag14 complexes, which is found to be superior to that of pure silver systems.
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744Sun, Q.; Gong, X. G.; Zheng, Q. Q.; Sun, D. Y.; Wang, G. H. Local magnetic properties and electronic structures of 3d and 4d impurities in Cu clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 10896– 10904, DOI: 10.1103/PhysRevB.54.10896Google Scholar744https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XmsFOhsb0%253D&md5=a7f380b92d3adf75f977c3d8346d38d1Local magnetic properties and electronic structures of 3d and 4d impurities in Cu clustersSun, Q.; Gong, X. G.; Zheng, Q. Q.; Sun, D. Y.; Wang, G. H.Physical Review B: Condensed Matter (1996), 54 (15), 10896-10904CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The local magnetic properties and electronic structures of Cu12R clusters with Ih and Oh symmetries (R = Sm, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag) were systematically studied with the d.-functional formalism, and the Kohn-Sham equation is solved self-consistently with the discrete variational method. By calcg. the binding energies for 3d series, the icosahedral structure is more stable than the octahedron structure. Pd and Ag doping can enhance the stability of a cluster, and the alloying effects in such doped clusters have an important effect on binding energy. The electronic structures calcd. in equil. configurations show that the clusters with R = Cu, Cr, Mo, or Ag have closed electronic shells, while the others have open electronic shells. In particular, the authors have performed comprehensive calcns. on the local magnetism of impurities in a cluster, and found that the behavior of local magnetism for 3d and 4d impurities in Cu12 clusters is different from that in bulk as well as from that in Al12 clusters. In contrast to the d-d interaction picture for local magnetism in the d-band bulk host, there are more complicated interactions acting in clusters to affect the local magnetism of impurities: the interactions of the Cu-p orbital with R-spd orbitals play a crucial role on the local magnetic moment for impurities with more than a half-filled d shell, such as Mn, Fe, Co, Ni, Tc, Ru, and Rh; the interactions of the Cu-d orbital with R-spd orbitals contribute to the local magnetic moment for impurities with a less than half-filled d shell, such as Sc, Ti, V, Y, Zr, and Nb. The authors have also tested and discussed the Stoner-like criterion for the occurrence of a local moment in a cluster.
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745Holtzl, T.; Veldeman, N.; De Haeck, J.; Veszpremi, T.; Lievens, P.; Nguyen, M. T. Growth mechanism and chemical bonding in scandium-doped copper clusters: Experimental and theoretical study in concert. Chem. - Eur. J. 2009, 15, 3970– 3982, DOI: 10.1002/chem.200802372Google ScholarThere is no corresponding record for this reference.
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746Janssens, E.; Lievens, P. Growth mechanisms for doped clusters. Adv. Nat. Sci.: Nanosci. Nanotechnol. 2011, 2, 023001, DOI: 10.1088/2043-6262/2/2/023001Google Scholar746https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXptFGktLw%253D&md5=56e5555598b9a8e8d00de4752b539caaGrowth mechanisms for doped clustersJanssens, Ewald; Lievens, PeterAdvances in Natural Sciences: Nanoscience and Nanotechnology (2011), 2 (2), 023001/1-023001/8CODEN: ANSNCK; ISSN:2043-6262. (Institute of Physics Publishing)A review. Structural growth mechanisms for metal doped nanoclusters are investigated in combined exptl. and theor. studies. In particular, silicon, copper and gold clusters incorporating a transition metal dopant atom are investigated: Sin X (X = Cu, V), CunSc+ and AunY+ with n < 20. The doped clusters are produced with a dual-target dual-laser vaporization source. Structural information about the doped nanoclusters is provided by IR multi-photon dissocn. spectroscopy. Their size and compn. dependent stability is studied with photofragmentation and mass spectrometry. A detailed understanding of the role of the dopant atom in the structural growth and in the electronic structure of the clusters is obtained by comparison with quantum chem. computations using d. functional theory.
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747Hirabayashi, S.; Ichihashi, M. Reactions of Ti- and V-doped Cu cluster cations with nitric oxide and oxygen: Size dependence and preferential NO adsorption. J. Phys. Chem. A 2016, 120, 1637– 1643, DOI: 10.1021/acs.jpca.6b00206Google Scholar747https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xjs1GqsLs%253D&md5=30e2ed34b0317e4dbb068223890b8f77Reactions of Ti- and V-Doped Cu Cluster Cations with Nitric Oxide and Oxygen: Size Dependence and Preferential NO AdsorptionHirabayashi, Shinichi; Ichihashi, MasahikoJournal of Physical Chemistry A (2016), 120 (10), 1637-1643CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Reactions of Cu cluster cations doped with an early transition metal atom, CunTi+ (n = 4-15) and CunV+ (n = 5-14, 16), with NO and O2 were studied at a near-thermal collision energy using a guided ion beam tandem mass spectrometer. Most of the clusters adsorb NO and O2 under single collision conditions, and this reaction is often followed by the release of Cu atoms. For both Ti- and V-doped Cu clusters, the total cross sections for the reaction with NO increase gradually with the cluster size up to n ≈ 11 and then decrease rapidly, whereas those with O2 are almost const. in n ≤ 12 and then decrease. The size dependence of the reactivity toward NO is found to correlate with that of the adsorption energy calcd. by the d. functional theory method; CunTi+ clusters exhibit the larger reaction cross sections when they have the larger adsorption energies. The calcns. of CunTi+ also show that a structural transition from a Ti-exposed structure to Ti-encapsulated one occurs around n = 12. A geometric property of the clusters, i.e., the position of the dopant atom, is a detg. factor of reactivity. The Ti- and V-doping dramatically improves the reactivity of Cu cluster cations toward NO but it does not affect that toward O2 significantly. As a result, most of the Ti- and V-doped Cu clusters are more reactive toward NO than toward O2. The authors also studied the multiple-collision reaction of Cu7Ti+ with NO and obtained the cluster dioxide, Cu3TiO2+, as a product ion, which suggests that the dissocn. of NO and the subsequent formation/release of N2 take place.
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748Pham, H. T.; Cuong, N. T.; Tam, N. M.; Tung, N. T. A systematic investigation on CrCun clusters with n = 9-16: Noble gas and tunable magnetic property. J. Phys. Chem. A 2016, 120, 7335– 7343, DOI: 10.1021/acs.jpca.6b04221Google Scholar748https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVSgtbfL&md5=623771a2767029cfc5b31a73b1b9a81fA Systematic Investigation on CrCun Clusters with n = 9-16: Noble Gas and Tunable Magnetic PropertyPham, Hung Tan; Cuong, Ngo Tuan; Tam, Nguyen Minh; Tung, Nguyen ThanhJournal of Physical Chemistry A (2016), 120 (37), 7335-7343CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)A systematic investigation on structure, dissocn. behavior, chem. bonding, and magnetic property of Cr-doped Cun clusters (n = 9-16) is carried out using the mean of d. functional theory calcns. It is found that CrCu12 is a crucial size, preferring an icosahedral Cu12 cage with the central Cr dopant. Smaller cluster sizes appear as on the way to form the CrCu12 icosahedron while larger ones are produced by attaching addnl. Cu atoms to the CrCu12 core. The presence of Cr dopant obviously enhances the stability of CrCun clusters in comparison to that of pure counterparts. Exceptionally stable CrCu12 has an 18-electron closed-shell electronic structure, mimicking a noble gas in the viewpoint of superatom concept. Anal. on cluster electronic structure shows that the interplay between 3d orbitals of Cr and 4s orbitals of Cu has a vital role on the magnetic properties of CrCun clusters.
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749Sarugaku, S.; Murakami, R.; Matsumoto, J.; Kawano, T.; Arakawa, M.; Terasaki, A. Size-dependent reactivity of nickel-doped silver cluster cations toward oxygen: Electronic and geometric effects. Chem. Lett. 2017, 46, 385– 388, DOI: 10.1246/cl.161094Google Scholar749https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVGrtb7J&md5=03396b8554c0667392312f7d5275c5a2Size-dependent Reactivity of nickel-doped silver cluster cations toward oxygen: electronic and geometric effectsSarugaku, Shun; Murakami, Ryohei; Matsumoto, Jumpei; Kawano, Tomoki; Arakawa, Masashi; Terasaki, AkiraChemistry Letters (2017), 46 (3), 385-388CODEN: CMLTAG; ISSN:0366-7022. (Chemical Society of Japan)Size-dependent reaction of nickel-doped silver cluster cations (AgN-1Ni+: N = 5-14) was investigated for oxygen as the reactant mol. A dramatic drop in the reactivity obsd. for N ≥ 9 is attributed to the encapsulation of the nickel atom, i.e., screening the active site at larger sizes. The reactivity min. obsd. at N = 10 is ascribed to the closed electronic shell of Ag9Ni+ formed by 18 valence electrons from Ag5s, Ni4s, and Ni3d, suggesting delocalized d electrons.
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750Graciani, J.; Oviedo, J.; Sanz, J. F. V@Au12-: An improved novel catalyst for CO oxidation?. J. Phys. Chem. B 2006, 110, 11600– 11603, DOI: 10.1021/jp057322fGoogle Scholar750https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XkslWlt70%253D&md5=729ac56b77e3a73b9fd1aef42a4fef1eV@Au12-: An Improved Novel Catalyst for CO Oxidation?Graciani, Jesus; Oviedo, Jaime; Sanz, Javier F.Journal of Physical Chemistry B (2006), 110 (23), 11600-11603CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)The catalytic properties toward CO combustion of an encapsulated cluster, V@Au12-, have been explored by means of plane-wave pseudopotential d.-functional theory calcns. Single adsorption of both O2 and CO as well as coadsorption have been considered. The adsorption energy for the O2 mol. is about 0.3-0.4 eV which limits its use to low temps. However, in contrast to what happens for pure gold clusters, this system shows a remarkable capacity to bind a high no. of oxygen mols. Moreover, its icosahedral cluster is able to bind 12 CO mols., since all of the gold atoms are available. The bond between the metal cluster and the oxygen mol. mainly arises from a charge transfer from the metal toward the πg antibonding O2 orbitals, while in the case of CO mol., the classical σ-donation π-back-donation mechanism is obsd. Finally, no coadsorption effects are found when both mols. are adsorbed, the interaction properties between the cluster and the substrates remain basically unaltered.
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751Gao, Y.; Shao, N.; Bulusu, S.; Zeng, X. C. Effective CO oxidation on endohedral gold-cage nanoclusters. J. Phys. Chem. C 2008, 112, 8234– 8238, DOI: 10.1021/jp801262vGoogle Scholar751https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlvFSgtLk%253D&md5=a40798b8246f2d211f71b5883a2312b8Effective CO Oxidation on Endohedral Gold-Cage NanoclustersGao, Yi; Shao, Nan; Bulusu, Satya; Zeng, X. C.Journal of Physical Chemistry C (2008), 112 (22), 8234-8238CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Ab initio calcns. are performed to study the CO oxidn. on six endohedral gold-cage clusters (W@Au12, Nb@Au13, Zr@Au14, Sc@Au15, Ca@Au16, and Na@Au17). The calcns. suggest that three clusters (Nb@Au13, Zr@Au14, and Sc@Au15) can be very effective nanocatalysts. The reaction energy barriers are lower than those assocd. with either bare gold clusters or gold surfaces and are comparable to those assocd. with the support Au clusters. The effective CO oxidn. can be attributed to the charge transfer from the dopant to the gold cage, the low coordination no. for gold atoms on the cages, as well as the fluxionality of the cage.
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752Kim, H. Y.; Kim, D. H.; Ryu, J. H.; Lee, H. M. Design of robust and reactive nanoparticles with atomic precision: 13Ag-Ih and 12Ag-1X (X = Pd, Pt, Au, Ni, or Cu) Core-Shell Nanoparticles. J. Phys. Chem. C 2009, 113, 15559– 15564, DOI: 10.1021/jp905047hGoogle Scholar752https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXps1Klurw%253D&md5=68d14edf025c3d9e933c338f98f4f807Design of Robust and Reactive Nanoparticles with Atomic Precision: 13Ag-Ih and 12Ag-1X (X = Pd, Pt, Au, Ni, or Cu) Core-Shell NanoparticlesKim, Hyun You; Kim, Da Hye; Ryu, Ji Hoon; Lee, Hyuck MoJournal of Physical Chemistry C (2009), 113 (35), 15559-15564CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)D. functional theory calcns. and a modified reaction model confirm that the initial high CO oxidn. reactivity of a 13Ag-Ih nanoparticle from an icosahedron (Ih) structure is immediately diminished as the nanoparticle is transformed to an amorphous state by a reaction-driven structural change. The adsorption of O2 and the formation of a four-center intermediate metastable state from coadsorbed CO and O2 pos. charge the 13Ag-Ih nanoparticle, and the repulsive force between the Ag atoms causes the reaction-driven structural change of the 13Ag-Ih nanoparticle. When one central Ag atom is substituted with a solute atom, a core-shell type of 12Ag-1X-Ih (X = Pd, Pt, Au, Ni, or Cu) bimetallic nanoparticle is stabilized. Among them, the authors propose the 12Ag-1Pd nanoparticle as a robust and reactive Ag-based bimetallic nanoparticle for CO oxidn. The structural fluxionality accounts for the catalytic activity of small nanoparticles.
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753Kim, H. Y.; Han, S. S.; Ryu, J. H.; Lee, H. M. Balance in adsorption energy of reactants steers CO oxidation mechanism of Ag13 and Ag12Pd1 nanoparticles: Association mechanism versus carbonate-mediated mechanism. J. Phys. Chem. C 2010, 114, 3156– 3160, DOI: 10.1021/jp9111553Google Scholar753https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlKku7k%253D&md5=23e542cccd65e27e19aa39ec89492117Balance in Adsorption Energy of Reactants Steers CO Oxidation Mechanism of Ag13 and Ag12Pd1 Nanoparticles: Association Mechanism versus Carbonate-Mediated MechanismKim, Hyun You; Han, Sang Soo; Ryu, Ji Hoon; Lee, Hyuck MoJournal of Physical Chemistry C (2010), 114 (7), 3156-3160CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)CO oxidn. is a very useful ref. reaction for catalysis by nanoparticles (NP). Two reaction models (assocn. mechanism [AM] and carbonate-mediated mechanism [CMM]) have been suggested for CO oxidn. catalyzed by small NP; however, it is unclear when and why these mechanisms preferentially operate. For Ag13 cryst. NP and Ag12Pd1 core-shell NP, a d. functional theory calcn. and micro-kinetic reaction model detd. the different reaction mechanisms can operate with different reaction intermediates, accompanied by a balance in the adsorption energy of reactants. Adsorption energy of adsorbates variations can result from the interchange of the 2 reaction mechanisms, even in a single NP. An AM operates when both reactants interact strongly with a NP; the contribution of the CMM in CO oxidn. increases when a CO mol. interacts weakly or not at all with a NP.
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754Zhou, S.; Pei, W.; Du, Q.; Zhao, J. Foreign atom encapsulated Au12 golden cages for catalysis of CO oxidation. Phys. Chem. Chem. Phys. 2019, 21, 10587– 10593, DOI: 10.1039/C9CP01517EGoogle Scholar754https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXosVCgtbo%253D&md5=f08e9b9085eb3b9971786c4d990eb577Foreign atom encapsulated Au12 golden cages for catalysis of CO oxidationZhou, Si; Pei, Wei; Du, Qiuying; Zhao, JijunPhysical Chemistry Chemical Physics (2019), 21 (20), 10587-10593CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Gold clusters are known for their unique catalytic properties, among which, endohedral gold clusters doped with heteroatoms have remarkable stabilities, with electronic structures tunable by both cluster size and doping element. Thus, it is intriguing and imperative to understand the principles for modulating the catalytic behaviors of these novel clusters. Here, we exploit exptl. produced M@Au12 (M = transition metal) cage clusters for catalysis of CO oxidn. The doping effects of 3d, 4d and 5d transition metals (V, Cr, Mn, Nb, Mo, Ta, W and Re) on the catalytic properties were systematically explored by first-principles calcns. Among the considered M@Au12 clusters, Cr@Au12 and Mn@Au12 provide a suitable binding strength with reaction intermediates and are highly active for CO oxidn. with reaction barriers of 0.41 eV under the Langmuir-Hinshelwood mechanism. More importantly, we establish a distinct relationship between catalytic activity and the M-Au bond order and the d orbital center of the M@Au12 clusters, which would help tailor their catalytic performance with atomistic precision and enable utilization of these stable gold cages for catalysis of various chem. processes.
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755Fu, Y.; Li, J.; Wang, S.-G. Bonding and electronic structures in W@Au12 AE complexes (AE = NO+, CO, BF, CN-, or BO-): Analogies among ligands isoelectronic to carbon monoxide. J. Mol. Model. 2010, 16, 9– 16, DOI: 10.1007/s00894-009-0517-yGoogle Scholar755https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXlslGitbw%253D&md5=5f7edc6495b90eb393f1b6dddfb876b8Bonding and electronic structures in W@Au12AE complexes (AE= NO+, CO, BF, CN-, or BO-): analogies among ligands isoelectronic to carbon monoxideFu, Yi; Li, Jia; Wang, Shu-GuangJournal of Molecular Modeling (2010), 16 (1), 9-16CODEN: JMMOFK; ISSN:0948-5023. (Springer GmbH)A theor. study on the geometries and electronic structures of W@Au12AE (AE = NO+, BF, CN-, or BO-) was carried out to gain insight into interactions between W@Au12 and ligands isoelectronic with CO. The best configuration for the adsorption site is on-top type for all five complexes. After complexing with boron ligands (BF or BO-), the axial Au-W bond distance in W@Au12 is lengthened notably, but NO+ has the opposite effect on the axial Au-W bond. A charge transfer and energy decompn. anal. shows that the metal-ligand bonds have enhanced σ-donation strength from NO+ to BO-. Furthermore, the A-E bond strength in the complexes becomes weaker with stronger π-back-donation interactions. Finally, W@Au12CO has the largest HOMO-LUMO gap, making it the most stable in terms of kinetic stability.
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756Sinai, H. E.; Avnir, D. Adsorption-induced symmetry distortions in W@Au12 nanoclusters, leading to enhanced hyperpolarizabilities. Isr. J. Chem. 2016, 56, 1076– 1081, DOI: 10.1002/ijch.201600082Google ScholarThere is no corresponding record for this reference.
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757Chen, L.; Gao, Y.; Cheng, Y.; Su, Y.; Wang, Z.; Li, Z.; Zhang, R.-Q. Strong core@shell dependence in surface-enhanced raman scattering of pyridine on stable 13-atom silver-caged bimetallic clusters. J. Phys. Chem. C 2015, 119, 17429– 17437, DOI: 10.1021/acs.jpcc.5b04453Google Scholar757https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFWqt7nP&md5=503ebe41a3aaa32a484a80fd19fd047dStrong Core@Shell Dependence in Surface-Enhanced Raman Scattering of Pyridine on Stable 13-Atom Silver-Caged Bimetallic ClustersChen, Lei; Gao, Yang; Cheng, Yingkun; Su, Yanbin; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-QinJournal of Physical Chemistry C (2015), 119 (30), 17429-17437CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)From calcns. using time-dependent d. functional theory, the authors conducted detailed analyses of the surface-enhanced Raman scattering (SERS) of pyridine adsorbed on 13-atom icosahedral M@Au12 and M@Ag12 (M = Mo, W) clusters. Surprisingly, although the SERS enhancements for all complexes can reach the order of 104, the signals of pyridine on M@Ag12 at charge transfer (CT) transition excitations are twice as much as that of pyridine on M@Au12, and the corresponding energies used for SERS excitations are significantly different in the low-energy region of 1.63-2.10 eV. The interactive modulation between the core and shell can produce varying strong CT transitions from metal clusters to pyridine, which tunes the SERS enhancements with altered optical properties. The complexes of pyridine on Ag-caged clusters are more easily influenced by the tunability of the core than that of pyridine on Au-caged clusters. Analyses are expected to provide a theor. basis for exptl. synthesizing multicomponent SERS substrates and exploring the dependence of SERS enhancement on the synergies between the different components in core@shell binary metal clusters.
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758Chen, L.; Gao, Y.; Cheng, Y.; Li, H.; Wang, Z.; Li, Z.; Zhang, R.-Q. Nonresonant chemical mechanism in surface-enhanced Raman scattering of pyridine on M@Au12 clusters. Nanoscale 2016, 8, 4086– 4093, DOI: 10.1039/C5NR07246HGoogle Scholar758https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XlvV2gtQ%253D%253D&md5=bd8ecedbfd7d98570c67440438ef91ceNonresonant chemical mechanism in surface-enhanced Raman scattering of pyridine on M@Au12 clustersChen, Lei; Gao, Yang; Cheng, Yingkun; Li, Haichao; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-QinNanoscale (2016), 8 (7), 4086-4093CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)By employing d. functional theory (DFT), this study presents a detailed anal. of nonresonant surface-enhanced Raman scattering (SERS) of pyridine on M@Au12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, and Re+)-the stable 13-atom neutral and charged gold buckyball clusters. Changing the core atom in M@Au12 enabled us to modulate the direct chem. interactions between pyridine and the metal cluster. The results of our calcns. indicate that the ground-state chem. enhancement does not increase as the binding interaction strengthens or the transfer charge increases between pyridine and the cluster. Instead, the magnitude of the chem. enhancement is governed, to a large extent, by the charged properties of the metal clusters. Pyridine on M@Au12 anion clusters exhibits strong chem. enhancement of a factor of about 102, but the equiv. increase for pyridine adsorbed on M@Au12 neutral and cation clusters is no more than 10. Polarizability and deformation d. analyses clearly show that compared with the neutral and cation clusters, the anion clusters have more delocalized electrons and occupy higher energy levels in the pyridine-metal complex. Accordingly, they produce larger polarizability, leading to a stronger nonresonant enhancement effect.
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759Chen, L.; Wang, Z.; Li, Z.; Zhang, R.-Q. Chemical coupling SERS properties of pyridine on silver-caged metal clusters M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+). J. Electron. Mater. 2017, 46, 3904– 3909, DOI: 10.1007/s11664-016-4993-4Google Scholar759https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1OisL3K&md5=79ffba8702aa132ddd8acc9c26aacc03Chemical Coupling SERS Properties of Pyridine on Silver-Caged Metal Clusters M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+)Chen, Lei; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-QinJournal of Electronic Materials (2017), 46 (7), 3904-3909CODEN: JECMA5; ISSN:0361-5235. (Springer)Using d. functional theory, this work presents a comprehensive anal. of nonresonant surface-enhanced Raman scattering enhancement of pyridine on M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+). Computational results indicate that the chem. enhancement of pyridine on M@Ag12 is closely assocd. with the charge properties of silver-caged clusters. Pyridine on neg. clusters exhibits the strongest chem. enhancement with a factor of about 103, while the chem. enhancement is only about 102 for pyridine on neutral clusters and 10 for pyridine on pos. clusters. The polarizability analyses elucidate the nature of the chem. enhancement that delocalized electrons of neg. adsorption systems occupy higher MOs than those of neutral and pos. adsorption systems, which can lead to stronger nonresonant chem. enhancement.
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760Jensen, F.; Toftlund, H. Structure and stability of C24 and B12N12 isomers. Chem. Phys. Lett. 1993, 201, 89– 96, DOI: 10.1016/0009-2614(93)85039-QGoogle Scholar760https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXosl2htw%253D%253D&md5=373f469f7099b26dc8487e616e593386Structure and stability of carbon (C24) fullerene and boron nitride (B12N12) fullerene isomersJensen, Frank; Toftlund, HansChemical Physics Letters (1993), 201 (1-4), 89-96CODEN: CHPLBC; ISSN:0009-2614.The structures and stabilities of four possible isomers of C24 and B12N12 were studied by means of ab-initio calcns. at the MP2/DZP level. The four geometries are a monocyclic ring, a graphite-like sheet, and two fullerene structures. For C24, the graphite-like isomer is lowest in energy; while a B12N12 fullerene consisting of 4- and 6-membered rings appears to be quite stable. It is possible that this fullerene plays the same role for boron nitride as C60 does for carbon.
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761Silaghi-Dumitrescu, I.; Haiduc, I.; Sowerby, D. B. Fully inorganic (carbon-free) fullerenes? The boron-nitrogen case. Inorg. Chem. 1993, 32, 3755– 3758, DOI: 10.1021/ic00069a034Google Scholar761https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlsFWit7o%253D&md5=8c49a16f5405bad1dea05b7567bf7075Fully inorganic (carbon-free) fullerenes? The boron-nitrogen caseSilaghi-Dumitrescu, Ioan; Haiduc, Ionel; Sowerby, D. BryanInorganic Chemistry (1993), 32 (17), 3755-8CODEN: INOCAJ; ISSN:0020-1669.Closed cages contg. only B and N atoms can be constructed from 4-membered B2N2 rings and 6-membered B3N3 rings. The ring-spiral algorithm applied to such cages and HMO calcns. suggest that stable accordion-shaped cages, B12+3nN12+3n can exist. From different principles, a B22N22 cage seems also possible.
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762Sun, M.-L.; Slanina, Z.; Lee, S.-L. Square/hexagon route towards the boron-nitrogen clusters. Chem. Phys. Lett. 1995, 233, 279– 283, DOI: 10.1016/0009-2614(94)01441-WGoogle Scholar762https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjs1Crsbo%253D&md5=772602172d842ce326269fa7d269382aSquare/hexagon route towards the boron-nitrogen clustersSun, Mei-Ling; Slanina, Zdenek; Lee, Shyi-LongChemical Physics Letters (1995), 233 (3), 279-83CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)A new route towards B/N clusters is considered, based on squares and hexagons. The pattern always requires six squares while the no. of hexagons increases linearly with the no. of atoms. The route can produce species of similar or even higher stability compared to the conventional pentagon-hexagon pattern. Four particular stoichiometries emerge from the available Austin-model-one-MO (AM1) computations: B12N12, B28N28, B36N36, and B36N24.
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763Seifert, G.; Fowler, P.; Mitchell, D.; Porezag, D.; Frauenheim, T. Boron-nitrogen analogues of the fullerenes: Electronic and structural properties. Chem. Phys. Lett. 1997, 268, 352– 358, DOI: 10.1016/S0009-2614(97)00214-5Google Scholar763https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXis1Wmt7w%253D&md5=d768cbd9bfb5a87c2fe588db5cc7faf3Boron-nitrogen analogs of the fullerenes: electronic and structural propertiesSeifert, G.; Fowler, P. W.; Mitchell, D.; Porezag, D.; Frauenheim, Th.Chemical Physics Letters (1997), 268 (5,6), 352-358CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)On the basis of a systematic d. functional tight-binding study of boron-nitrogen polyhedra (BN)x composed entirely of four- and six-membered rings, it is predicted that octahedron-like structures B12N12, B16N16 and B28N28 are "magic" (i.e. anomalously stable) clusters. The IR spectrum of B12N12 is predicted. The similarities and differences between these "inorg. fullerenes" and the carbon-based equiv. are outlined. A high stability of the (BN)x clusters is found to correlate with a large HOMO-LUMO gap.
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764Stephan, O.; Bando, Y.; Loiseau, A.; Willaime, F.; Shramchenko, N.; Tamiya, T.; Sato, T. Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material. Appl. Phys. A: Mater. Sci. Process. 1998, 67, 107– 111, DOI: 10.1007/s003390050745Google Scholar764https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXktFKrsLk%253D&md5=48134849d1124be36cb3df6c18d559cbFormation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk materialStephan, O.; Bando, Y.; Loiseau, A.; Willaime, F.; Shramchenko, N.; Tamiya, T.; Sato, T.Applied Physics A: Materials Science & Processing (1998), 67 (1), 107-111CODEN: APAMFC; ISSN:0947-8396. (Springer-Verlag)An exptl. evidence for the formation of small BN cage-like mols., under electron-irradn. expts. of BN samples, is presented. Depending on the starting material, either close-packed agglomerates of small fullerene-like compds., or small nested fullerene-like compds. with ≤6 layers are found as irradn. derivs. The overall polyhedral shape of the BN cages is explained within the frame of the octahedral model previously proposed for BN analogs to fullerenes. The diams. of the smallest and most obsd. cages range from 0.4-0.7 nm, and are close to those of the B12N12B16N16 and B28N28 octahedra which were predicted to be magic clusters for the BN system from electronic structure calcns.
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765Golberg, D.; Bando, Y.; Stephan, O.; Kurashima, K. Octahedral boron nitride fullerenes formed by electron beam irradiation. Appl. Phys. Lett. 1998, 73, 2441– 2443, DOI: 10.1063/1.122475Google Scholar765https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXms1eqsrs%253D&md5=0cd0c4ef20917d2a8e78f4d449f6b349Octahedral boron nitride fullerenes formed by electron beam irradiationGolberg, D.; Bando, Y.; Stephan, O.; Kurashima, K.Applied Physics Letters (1998), 73 (17), 2441-2443CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Formation is reported of fullerenes with a reduced no. of layers (typically ≤3) in boron nitride (BN) which was subjected to in situ electron irradn. at 20 and 490 °C in a high resoln. 300 kV transmission electron microscope (HRTEM). The BN fullerenes exhibited B/N stoichiometry of ∼1 as confirmed by electron energy loss spectroscopy using a 1 nm electron probe. The fullerene HRTEM images revealed rectangle-like shapes when viewed in specific projections, unlike the quasispherical carbon fullerene morphol. The octahedral BN fullerene model of O. Stephan et al. (1998) is verified by the BN fullerene observations at different viewing angles.
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766Oku, T.; Kuno, M.; Narita, I. High-resolution electron microscopy and electronic structures of endohedral La@B36N36 clusters. Diamond Relat. Diamond Relat. Mater. 2002, 11, 940– 944, DOI: 10.1016/S0925-9635(01)00609-4Google Scholar766https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjvVemsrY%253D&md5=84827840f0b0009de9a2d5676a4c295dHigh-resolution electron microscopy and electronic structures of endohedral La@B36N36 clustersOku, Takeo; Kuno, Masaki; Narita, IchihitoDiamond and Related Materials (2002), 11 (3-6), 940-944CODEN: DRMTE3; ISSN:0925-9635. (Elsevier Science S.A.)La@36N36 endohedral metallofullerenes were synthesized for the first time, which was obsd. by high-resoln. electron microscopy, and a structure model was proposed. Image simulations of the La@36N36 clusters also showed the possible existence of a La atom inside the BN clusters. At. structures, structural stabilities and electronic structures of La@36N36, Fe@36N36 and B36N36 clusters were investigated by mol. mechanics and MO calcns., which showed that the B36N36 clusters are expanded by introducing doping atoms and the energy gap of B36N36 is reduced by introducing La and Fe atoms inside the B36N36 cluster.
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767Oku, T.; Kuno, M. Synthesis, argon/hydrogen storage and magnetic properties of boron nitride nanotubes and nanocapsules. Diamond Relat. Mater. 2003, 12, 840– 845, DOI: 10.1016/S0925-9635(02)00326-6Google Scholar767https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjsVeku78%253D&md5=07dc739da29264915d442f7f7e308f64Synthesis, argon/hydrogen storage and magnetic properties of boron nitride nanotubes and nanocapsulesOku, Takeo; Kuno, MasakiDiamond and Related Materials (2003), 12 (3-7), 840-845CODEN: DRMTE3; ISSN:0925-9635. (Elsevier Science B.V.)BN fullerene materials such as nanotubes, nanocapsules and nanocages were synthesized from LaB6, Co, Pd, Ti, Ni or Cu catalyst with boron powder by using an arc-melting method under an Ar-N atm.. For the BN nanocapsules with Co and CoOx nanoparticles, argon was detected by energy dispersive x-ray spectroscopy, and the nanocapsules had superparamagnetic properties. Thermogravimetry/differential thermogravimetric anal. of BN nanomaterials produced from LaB6 and Pd/boron powder showed the possibility of hydrogen storage of ∼3 wt.%.
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768Oku, T.; Narita, I.; Nishiwaki, A. Formation and structures of B36N36 and Y@B36N36 clusters studied by high-resolution electron microscopy and mass spectrometry. J. Phys. Chem. Solids 2004, 65, 369– 372, DOI: 10.1016/j.jpcs.2003.09.010Google Scholar768https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmsFOitQ%253D%253D&md5=160ce9791b950812d80557a6a57b3fdaFormation and structures of B36N36 and Y@B36N36 clusters studied by high-resolution electron microscopy and mass spectrometryOku, Takeo; Narita, Ichihito; Nishiwaki, AtsushiJournal of Physics and Chemistry of Solids (2004), 65 (2-3), 369-372CODEN: JPCSAW; ISSN:0022-3697. (Elsevier Science B.V.)High-resoln. electron microscopy, mass spectrometry and mol. mechanics/orbital calcns. of the boron nitride-based clusters showed the formation of B36N36 and YB36N36. Image simulations of these clusters confirmed the proposed structure model.
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769Oku, T.; Nishiwaki, A.; Narita, I. Formation and atomic structures of BnNn (n = 24–60) clusters studied by mass spectrometry, high-resolution electron microscopy and molecular orbital calculations. Phys. B 2004, 351, 184– 190, DOI: 10.1016/j.physb.2004.06.007Google Scholar769https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmt1WlsrY%253D&md5=20ec78d30dbd1d3a46e77d46b98ec0fbFormation and atomic structures of BnNn (n = 24-60) clusters studied by mass spectrometry, high-resolution electron microscopy and molecular orbital calculationsOku, Takeo; Nishiwaki, Atsushi; Narita, IchihitoPhysica B: Condensed Matter (Amsterdam, Netherlands) (2004), 351 (1-2), 184-190CODEN: PHYBE3; ISSN:0921-4526. (Elsevier)Boron nitride (BN) nanocage clusters (BnNn: n = 24-60) were synthesized by arc-melting method and detected by mass spectrometry and high-resoln. electron microscopy. Endohedral boron nitride clusters Y@BnNn would also be formed. The BN clusters consist of 4-, 6- and 8-membered BN rings satisfying the isolated tetragonal rule, which was optimized by MO calcns. The electronic structure showed that bandgap energies increase with increase of cluster size.
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770Beheshtian, J.; Tabar, M. B.; Bagheri, Z.; Peyghan, A. A. Exohedral and endohedral adsorption of alkaline earth cations in BN nanocluster. J. Mol. Model. 2013, 19, 1445– 1450, DOI: 10.1007/s00894-012-1702-yGoogle Scholar770https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtlWns7s%253D&md5=12b6af2a615d92a97fd5134b6742a7b2Exohedral and endohedral adsorption of alkaline earth cations in BN nanoclusterBeheshtian, Javad; Tabar, Mohammad Bigdeli; Bagheri, Zargham; Peyghan, Ali AhmadiJournal of Molecular Modeling (2013), 19 (3), 1445-1450CODEN: JMMOFK; ISSN:0948-5023. (Springer)Adsorption of three alk. earth cations inside and outside of a B12N12 nano-cage in aq. medium was investigated using d. functional theory. The results obtained are discussed in terms of thermodn., geometric, and electronic properties. Based on the calcn. of enthalpy changes at 298 K and 1 atm, the adsorption of the considered cations was found to be exothermic outside the cluster while it is endothermic inside. It was also found that the exohedral adsorption favorability of the cluster increases in the series: Ca2+ < Mg2+ << Be2+ with Gibbs free energy changes in the range of -0.08 to -1.53 eV at B3LYP/6-31G (d) level of theory. Overall, interaction of the cations with the cluster influences the electronic properties of the cluster through stabilizing the HOMO and LUMO as well as reducing the energy gap between them. However, the electronic properties changed much more in the case of endohedral adsorption in comparison with the exohedral adsorption.
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771Liu, Z.; Liu, X.; Zhao, J. Design of superhalogens using a core–shell structure model. Nanoscale 2017, 9, 18781– 18787, DOI: 10.1039/C7NR06431DGoogle Scholar771https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsl2ltb7N&md5=c0627f29ccef1c8cd42084090796c604Design of superhalogens using a core-shell structure modelLiu, Zhifeng; Liu, Xiaojuan; Zhao, JijunNanoscale (2017), 9 (47), 18781-18787CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)A review. Superhalogens, which have larger electron affinity than any halogen, play an important role in phys. chem. and materials design because of their applications in hydrogen storage and lithium-ion batteries. Inspired by the unique geometries and electronic properties of II-VI/III-V cage clusters, particularly the exptl. synthesized B12N12, we propose a core-shell structure model to design new superhalogens. The idea is assessed by conducting ab initio calcns. on endohedral cage clusters X@B12N12 (X = F, Cl, Br) and other similar systems. With an exceptionally large electron affinity of 5.36 eV, the stable F@B12N12 cluster behaves as a novel superhalogen that can serve as a building block for Li salts and hyperhalogens. The findings highlight a new route for the discovery of superhalogens and provide useful building blocks for the bottom-up design of materials.
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772Feng, L.; Lu, Y.; Kong, J.; Su, Z. Theoretical studies on the structure and properties of BN clusters (BN)n and endohedral metallo-BN clusters M@(BN)n. Comput. Theor. Chem. 2011, 964, 56– 64, DOI: 10.1016/j.comptc.2010.11.036Google Scholar772https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXitlartL0%253D&md5=37efc8e2818eadfe66ed7d5fe589b1a6Theoretical studies on the structure and properties of BN clusters (BN)n and endohedral metallo-BN clusters M@(BN)nFeng, Lei; Lu, Yinghua; Kong, Jun; Su, ZhongminComputational & Theoretical Chemistry (2011), 964 (1-3), 56-64CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The structure, stabilities, aromaticity, IR, Raman, and electronic spectra of BN clusters (BN)n (n = 12, 16, 20, 24, 28, 36) and endohedral metal-doped BN clusters M@(BN)n (M = Ca, Zn) have been predicted within d. functional theory. The energy gap between the HOMO and the LUMO does not change much with the size of BN cluster. However, such gap changes with metal atom in metal-doped BN clusters. Blue-shift of major peaks in IR spectra and red-shift of major peaks in Raman and electronic spectra occur in those BN clusters. The effect of doping of different metal atoms on the properties of the doped BN cluster has been revealed by the doping of Ca and Zn in those clusters.
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773Wang, J.; Ma, L.; Zhao, J.; Wang, B.; Wang, G. Stability and magnetic properties of transition metal atoms endohedral BnNn (n = 12–28) cages. J. Chem. Phys. 2008, 128, 084306, DOI: 10.1063/1.2833981Google Scholar773https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtVGqt7k%253D&md5=6c7549fa16f993374c5780bbf5d0bc44Stability and magnetic properties of transition metal atoms endohedral BnNn (n = 12-28) cagesWang, Jianguang; Ma, Li; Zhao, Jijun; Wang, Baolin; Wang, GuanghouJournal of Chemical Physics (2008), 128 (8), 084306/1-084306/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)First-principles calcns. have been conducted to systemically investigate the stability and magnetic properties of 3d and 4d transitional-metal (TM) atoms doped in the BnNn (n = 12, 16, 20, 24, 28) cages. Among those cages, the B24N24 is the optimal one for encapsulating 3d and 4d TM atoms according to the computed heat of formation. Inside B24N24 cage, 3d and 4d TM dopants belonging to the same group in the Periodic Table exhibit similar magnetic behaviors. Most of the 3d and 4d TM atoms remain magnetic after doped in the B24N24 cage except for Ni, Zr, and Pd. The magnitudes of the remaining moments for 3d (except for Sc, Ti, and V) and 4d dopants are reduced from those of free atoms. The energy gaps are localized at the doped transition metal atoms. Encapsulations of two TM atoms inside the B24N24 cage were also considered. (c) 2008 American Institute of Physics.
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774Oliaey, A. R.; Boshra, A.; Khavary, M. Spin polarized bonding analysis of endohedral boron nitride nanocages: Density functional theory study. Phys. E 2010, 42, 2314– 2318, DOI: 10.1016/j.physe.2010.05.009Google Scholar774https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXos1GisLk%253D&md5=353cc9f00243ef3b11b9937baf63e01bSpin polarized bonding analysis of endohedral boron nitride nanocages: Density functional theory studyOliaey, Ahmad Reza; Boshra, Asadollah; Khavary, MahyarPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2010), 42 (9), 2314-2318CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)Spin polarized bonding anal. has been performed for B24N24 and its endohedral alkali metal derivs. (M@B24N24, M=Li, Na, K). The method used is d. functional theory (DFT) with hybrid functional B3LYP to evaluate spin-polarized natural bond orbitals (NBO). In the spin-polarized endohedral B24N24 models BN σ bonding occupancies decrease and the π bonding interactions vanish in the encapsulated cluster structure. The donor-acceptor interactions of NBOs change due to trapped atom. Encaged alkali atoms impact bonding characteristics of the nanocluster and establish new NBO interactions within the cluster structure.
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775Koi, N.; Oku, T.; Suganuma, K. s. Effects of endohedral element in B24N24 clusters on hydrogenation studied by molecular orbital calculations. Phys. E 2005, 29, 541– 545, DOI: 10.1016/j.physe.2005.06.023Google Scholar775https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFarsbvN&md5=347c707507cc77f5cd7337ba3c38920fEffects of endohedral element in B24N24 clusters on hydrogenation studied by molecular orbital calculationsKoi, Naruhiro; Oku, Takeo; Suganuma, Kat suakiPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2005), 29 (3-4), 541-545CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)Possibility of hydrogen gas storage in boron nitride (BN) clusters was investigated by MO calcns. Chemisorption calcn. was carried out for B24N24 with changing endohedral elements in BN cluster to compare the bonding energy at nitrogen and boron, which showed that Li is a suitable element for hydrogenation to B24N24.
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776Karachi, N.; Boshra, A.; Jadidi, S. DFT based insights into reactivity descriptors of encapsulated B24N24 nanocages. Struct. Chem. 2011, 22, 805– 809, DOI: 10.1007/s11224-011-9761-8Google Scholar776https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXos1Wmt7k%253D&md5=443231f781767eccbead74d5706bdb24DFT based insights into reactivity descriptors of encapsulated B24N24 nanocagesKarachi, Nima; Boshra, Asadollah; Jadidi, SiamakStructural Chemistry (2011), 22 (4), 805-809CODEN: STCHES; ISSN:1040-0400. (Springer)The authors present data on DFT(BLYP, B3LYP) geometries and reactivity indexes of B24N24, Li@B24N24, Na@B24N24, and K@B24N24 nanocages to be used in possible mol. engineering of endohedral BN-nanocages. They calcd. HOMO-LUMO band gap, chem. hardness, chem. potential, vertical electron affinity, and vertical ionization potential, as well as the global electrophilicity index, ω(I, A). The effect of MQZVP basis set on total electronic energy of the clusters was also studied.
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777Su, B.; Feng, X.; Guo, X.; Li, N. Polynitrogen clusters encapsulated inside B24N24 fullerene-like nanocages: Nanoscale high energy materials studied by density functional theory. Inorg. Chim. Acta 2017, 456, 128– 135, DOI: 10.1016/j.ica.2016.10.039Google Scholar777https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVahurbE&md5=7d4222902bd93bd9cd3920a8a8c168b9Polynitrogen clusters encapsulated inside B24N24 fullerene-like nanocages: Nanoscale high energy materials studied by density functional theorySu, Bo; Feng, Xiuli; Guo, Xueyong; Li, NanInorganica Chimica Acta (2017), 456 (), 128-135CODEN: ICHAA3; ISSN:0020-1693. (Elsevier B.V.)The complexes of polynitrogen clusters encapsulated inside o-B24N24 and s-B24N24 fullerene-like nanocages, Nn@o-B24N24 and Nn@s-B24N24, are predicted as nanoscale high energy materials and optimized at ωB97X-D theor. levels with the basis set of 6-31G(d). It is found that the max. of 10 N atoms can be encapsulated inside o-B24N24 and 9 N atoms inside s-B24N24. The encapsulated Nn clusters in Nn@o-B24N24 have the similar configurations for n = 1-5 and 7, and the different configurations for n = 6, 8 and 9 to those in Nn@s-B24N24. The total energy (ENn@B24N24) anal. and percentage relative elongation (ε = (R/R0 - 1) × 100%), all indicate that s-B24N24 is better for encapsulating the Nn clusters (n ≤ 5), and worse for the Nn clusters (n ≥ 6) than o-B24N24. The HOMO-LUMO energy gap of Nn@B24N24 generally show a gradual decrease with the increase of the no. of nitrogen atom of the encaged Nn in odd or even no., resp. And different from the pure B24N24, the electron d. patterns indicate that for complexes Nn@B24N24, the HOMO for n = 6-9 and the LUMO for n = 2-9 mainly conc. in the encaged Nn. The NBO anal., the Mulliken population anal. and the topol. anal. of the electron localization function (ELF) all demonstrate that there exist some covalent interactions between the encapsulated Nn clusters and the nanocages for the Nn@o-B24N24 (n = 7,9) and Nn@s-B24N24 (n = 5,7,9), while other complexes only have Van der Waals interactions.
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778Wang, Q.; Sun, Q.; Oku, T.; Kawazoe, Y. First-principles study of La–B36N36 cage. Phys. B 2003, 339, 105– 109, DOI: 10.1016/j.physb.2003.08.119Google Scholar778https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovFOjtLk%253D&md5=e01fa2eeaab0f4ab3cff689f257911a6First-principles study of La-B36N36 cageWang, Q.; Sun, Q.; Oku, T.; Kawazoe, Y.Physica B: Condensed Matter (Amsterdam, Netherlands) (2003), 339 (2-3), 105-109CODEN: PHYBE3; ISSN:0921-4526. (Elsevier Science B.V.)Based on the exptl. studies of La-B36N36 cluster (Takeo Oku et al., Diamond Rel. Mater. 11 (2002) 940), first principles calcns. using DFT-GGA and the projector-augmented wave methods were performed on La-B36N36 cluster. The structure was fully optimized. The encapsulation of a La atom inside the B36N36 cage is energetically favorable, although the interaction between the La atom and the cage is weak. In order to optimize the interactions with the cage, the La atom is shifted off the cage center. The HOMO-LUMO gap is much reduced by doping; the complex cage carries a magnetic moment of 1.0μB.
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779Nishiwaki, A.; Oku, T.; Suganuma, K. Atomic and electronic structures of endohedral B36N36 clusters with doping elements studied by molecular orbital calculations. Phys. B 2004, 349, 254– 259, DOI: 10.1016/j.physb.2004.03.308Google Scholar779https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXksF2qu7s%253D&md5=49d57b27c6a173d4dbc3ae126ccbc0bbAtomic and electronic structures of endohedral B36N36 clusters with doping elements studied by molecular orbital calculationsNishiwaki, Atsushi; Oku, Takeo; Suganuma, KatsuakiPhysica B: Condensed Matter (Amsterdam, Netherlands) (2004), 349 (1-4), 254-259CODEN: PHYBE3; ISSN:0921-4526. (Elsevier Science B.V.)At. and electronic structures of endohedral B36N36 clusters with doping elements were studied by MO calcns. Total energy calcn. showed that some elements stabilize and expand the B36N36 structure. Band gap energies of the B36N36 clusters were found to be reduced by introducing a metal atom inside the cluster, which indicates controllability of the energy gap.
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780Boshra, A.; Monajjemi, M.; Aghaie, M.; Aghaie, H. Density functional theory investigation of natural bond orbital population analysis and gauge-including atomic orbital NMR tensors of K@B36N36. J. Comput. Theor. Nanosci. 2010, 7, 1147– 1158, DOI: 10.1166/jctn.2010.1466Google Scholar780https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXlsFWlu7o%253D&md5=2bc9985bc0b391139057decd097c2825Density functional theory investigation of natural bond orbital population analysis and gauge-including atomic orbital NMR tensors of K@B36N36Boshra, Asadollah; Monajjemi, Majid; Aghaie, Mehran; Aghaie, HosseinJournal of Computational and Theoretical Nanoscience (2010), 7 (6), 1147-1158CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)In this letter, D. Functional Theory (DFT) with hybrid functional B3LYP were employed to investigate several phys. and chem. properties of B36N36 and its encaged Potassium atom deriv. (K@B36N36). The quantum chem. computations in the framework of DFT for B36N36 cage and K@B36N36 has been performed using B3LYP level of theory supplemented with the std. 6-311G** basis set and utilizing the Gaussian 98 software package. The natural bond orbitals (NBO) calcns. were carried out using NBO 3.1 program as implemented in the Gaussian 98 package at the DFT/B3LYP level of theory and 6-31G* std. basis set. The encapsulation of Potassium atom into the B36N36 fullborene cage does not alter the cage chem. bonds considerably but makes HOMO-LUMO energy gap of the endohedral deriv. about 1.401 eV smaller than the computed value for the empty B36N36 cluster, also makes the system more stable because of its more favorable DFT mol. energy. The anal. of the natural bond orbital (NBO) suggests that there are about 0.18 electronic charge transferred from the encaged Potassium atom to the fullborene cluster. The occupancies of encapsulated cage NBOs showed a decrease and π bonds of bare B36N36 disappears introducing Potassium in to the cage. The donor-acceptor interactions between the cage and endo-Potassium atom were fully analyzed and predicted the mentioned interactions to be negligible. Some regional 2-electron delocalization obsd. between conjugated π bonds of B36N36 cage. Also GIAO nuclear magnetic shielding tensors of the atoms of the cages were computed and compared with each other.
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781Oliaey, A. R.; Boshra, A. DFT study of [Fe@B36N36]n+ (n = 2, 3) endohedral nanocages: Chemical reactivity, NBO analysis and thermochemistry. Phys. E 2013, 52, 136– 143, DOI: 10.1016/j.physe.2013.03.011Google Scholar781https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXosFyrtro%253D&md5=ce48ce9e6e7e193a9fd003d437e9af9bDFT study of [Fe@B36N36]n+ (n=2, 3) endohedral nanocages: Chemical reactivity, NBO analysis and thermochemistryOliaey, Ahmad reza; Boshra, AsadollahPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2013), 52 (), 136-143CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)In this study, the structures, vibrational stabilities, energy gaps of B36N36 nanocage and its two endohedral derivs., [Fe@B36N36]n+ (n=2, 3) were investigated via B3LYP hybrid functional of DFT. The transfer of charges and the inclusion energies of Fen+-encapsulated endohedrals were discussed as well. The detailed natural bond orbital (NBO) anal. revealed the nature of the hyperconjugative interactions of each nanocage. The NBO anal. specified an endohedral complex of Fe2+ with three nitrogen atoms of B36N36 while Fe3+ did not form such an endohedral complex. Also the global reactivity of the endohedrals based on NBO anal. was interpreted, and possible redox reactions of the studied nanocages were explained qual.
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782Batista, R. J.; Mazzoni, M. S.; Chacham, H. Boron nitride fullerene B36N36 doped with transition metal atoms: First-principles calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 035417, DOI: 10.1103/PhysRevB.75.035417Google Scholar782https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhs1eks7o%253D&md5=5022230b70448185739272dd97264a20Boron nitride fullerene B36N36 doped with transition metal atoms: First-principles calculationsBatista, Ronaldo J. C.; Mazzoni, Mario S. C.; Chacham, HelioPhysical Review B: Condensed Matter and Materials Physics (2007), 75 (3), 035417/1-035417/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We perform first-principles calcns. for the interaction of the transition metal atoms Fe, Co, and W, as well as the FeO mol., with the boron nitride fullerene B36N36. The stable structure of the atom-fullerene complexes may have the dopant atom either at the center of the cage or making covalent bonds with the fullerene wall, with similar total energies. We also find that the FeO mol. has a binding energy with the fullerene 2.5 eV larger than those of the transition metal atoms, and that it produces larger distortions in the cage. The electronic structure changes upon doping with the presence of several gap states. No magnetic moment is induced on the BN cage and, in general, the hybrid structures have the same magnetic moments as the isolated dopants.
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783Nigam, S.; Majumder, C. Magnetic needles encapsulated inside (BN)36 cage: Prediction of atomic, electronic, and magnetic structure from first principle calculations. Appl. Phys. Lett. 2007, 91, 223112, DOI: 10.1063/1.2815922Google Scholar783https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsVequ7rP&md5=efe1d4570ff464ed015622f8cac6d881Magnetic needles encapsulated inside (BN)36 cage: Prediction of atomic, electronic, and magnetic structure from first principle calculationsNigam, Sandeep; Majumder, ChiranjibApplied Physics Letters (2007), 91 (22), 223112/1-223112/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Using the 1st principle based d. functional theory formalism, the authors report the stability and structural aspects of small magnetic clusters inside chem. inert (BN)36 cage. Although the at. structures of small clusters showed significant changes due to the restrained imposed by the cage size, their stability improves inside the cage. Also, their magnetic structure remains almost unaltered in spite of being encaged. The implication of this work indicates that small magnetic particles can be protected inside the BN cage without losing their magnetic character for further applications.
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784Nigam, S.; Majumder, C. CO oxidation by BN–fullerene cage: Effect of impurity on the chemical reactivity. ACS Nano 2008, 2, 1422– 1428, DOI: 10.1021/nn8001455Google Scholar784https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXntVantrs%253D&md5=3faf2ddcd3d69537a53ed9f9f48fe45eCO Oxidation by BN-Fullerene Cage: Effect of Impurity on the Chemical ReactivityNigam, Sandeep; Majumder, ChiranjibACS Nano (2008), 2 (7), 1422-1428CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Using state of the art spin-polarized d. functional theory a chem. inert (BN)36 cluster can be activated by incorporating magnetic nanoparticles inside it. To illustrate this aspect the authors have calcd. the geometries and electronic structure of Fe(BN)36 and Fe4(BN)36 clusters, which showed the appearance of gap states localized on the impurity atoms. The reaction of O2 mols. with these clusters results in weak interaction and an elongation of the O-O bond. Further interaction of this complex species with an incoming CO mol. gives CO2. The reaction mechanism was studied via Langmuir-Hinshelwood and Elay-Rideal routes, and the min. energy path calcns. were performed using the elastic band method. These results have implications in designing novel materials based on metal nanoparticles for potential applications as industrial catalyst.
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785Nigam, S.; Kulshreshtha, S.; Majumder, C. Structural and magnetic isomers of M(BN)36 and M4(BN)36 clusters (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu): An ab initio density functional study. Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 075438, DOI: 10.1103/PhysRevB.77.075438Google Scholar785https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtFehu7c%253D&md5=8b4527ec41778ca7ad67b75e050e6fc9Structural and magnetic isomers of M(BN)36 and M4(BN)36 clusters (M=Ti,V,Cr,Mn,Fe,Co,Ni,Cu): An ab initio density functional studyNigam, Sandeep; Kulshreshtha, S. K.; Majumder, ChiranjibPhysical Review B: Condensed Matter and Materials Physics (2008), 77 (7), 075438/1-075438/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using the plane wave based pseudopotential method under the d. functional formalism, the geometry and electronic structures of M and M4 encaged (BN)36 clusters have been investigated, where M represents Ti, V, Cr, Mn, Fe, Co, Ni, and Cu atoms. The lowest energy structure of the M(BN)36 cluster shows that the impurity atom prefers to occupy either the center or off-center and close to the hexagonal ring of the cage. Geometry and electronic structures of M4 clusters have been calcd. in the bare state as well as inside the octahedral (BN)36 cluster. For free M4 clusters, except Cu4, which forms a planar rhombus structure, all other tetramer clusters adopt three dimensional bent rhombus or tetrahedron configuration. In sharp contrast, the equil. structure of M4 clusters inside the (BN)36 cage results in significant deformation in comparison to that in the free state. Unlike others, it is found that the stability of V4, Fe4, Co4, and Ni4 tetramers have been enhanced inside the cage. Importantly, these small clusters are found to retain their magnetic nature even after encaging them inside the (BN)36 cluster. In general, the magnetic moment of the M4 clusters are found to decrease inside the (BN)36 cage, except that for Cr4 cluster, which showed significant increase in the magnetic moment. The electronic d. of state anal. of these systems shows addnl. electronic states in the large gap of (BN)36 cluster originated by the M atoms or M4 clusters.
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786Wen, S.-H.; Deng, W.-Q.; Han, K.-L. Endohedral BN metallofullerene M@B36N36 complex as promising hydrogen storage materials. J. Phys. Chem. C 2008, 112, 12195– 12200, DOI: 10.1021/jp801893fGoogle Scholar786https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosFKlsLs%253D&md5=1bec8666d8edc87b4cd193dae1ce2413Endohedral BN Metallofullerene M@B36N36 Complex As Promising Hydrogen Storage MaterialsWen, Shu-Hao; Deng, Wei-Qiao; Han, Ke-LiJournal of Physical Chemistry C (2008), 112 (32), 12195-12200CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)By using first-principles calcns. within the frame of the d. functional theory, we have investigated the encapsulation of metal atoms (Li, Na, Be, Mg, and Ti) in a B36N36 cage and the effects of endohedral metal atoms on hydrogen storage in the B36N36. The calcns. showed that the chemisorption energies of the H on the B36N36 cage shell can be modified by the charged endohedral metal atom in the B36N36 cage, due to the electrostatic interaction and polarization of the cage electrons. Endohedral metal atoms also exert influences on H2 mols. residing inside the B36N36 cage. For Ti@B36N36, we predict a high hydrogen content (8 wt %) structure with a full H coverage on the outer cage shell and with the Kubas complex in the inner cavity.
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787Liang, W.; Jia, J.; Lv, J.; Wu, H. Electronic structure, stability and magnetic properties of small M1–4 (M = Fe, Co, Ni) clusters encapsulated inside a (BN)48 cage. Chem. Phys. Lett. 2015, 622, 57– 62, DOI: 10.1016/j.cplett.2014.12.020Google Scholar787https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht1Ogsb0%253D&md5=70db4080388ad0ef114a9036d3a4844eElectronic structure, stability and magnetic properties of small M1-4(M = Fe, Co, Ni) clusters encapsulated inside a (BN)48 cageLiang, Wenjuan; Jia, Jianfeng; Lv, Jin; Wu, HaishunChemical Physics Letters (2015), 622 (), 57-62CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometrical structure and magnetic properties of M1-4(M = Fe, Co and Ni) clusters within a (BN)48 cage were calcd. at the BPW91/LanL2DZ level. The small M1-4 clusters generally prefer an off-centered position near the hexagonal rings in the (BN)48 cages. The (BN)48 cages can increase the stability of these small magnetic clusters while protecting their magnetic nature.
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788Liang, W.; Jia, J.; Lv, J.; Wu, H. Density functional theory study of Mo-doped M@(BN)48 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) clusters. J. Mol. Struct. 2016, 1108, 92– 95, DOI: 10.1016/j.molstruc.2015.11.057Google Scholar788https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVClsbfF&md5=245285da113db661604a14bc2fd3194fDensity functional theory study of Mo-doped M@(BN)48 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) clustersLiang, Wenjuan; Jia, Jianfeng; Lv, Jin; Wu, HaishunJournal of Molecular Structure (2016), 1108 (), 92-95CODEN: JMOSB4; ISSN:0022-2860. (Elsevier B.V.)The structure and magnetic properties of Mo-doped M@(BN)48 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) clusters were calcd. at BPW91/LanL2DZ level. The magnetic nature of the clusters M@(BN)48 significantly changed when doping with Mo atom, except for Co@(BN)48. Only the magnetic moment for the CrMo@(BN)48 cluster was decreased to zero. Thus, M@(BN)48 clusters can be selected as the model system to detect Mo atom by the change of the magnetic moment.
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789Kumar, V.; Kawazoe, Y. Hydrogenated caged clusters of Si, Ge, and Sn and their endohedral doping with atoms: Ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 155425, DOI: 10.1103/PhysRevB.75.155425Google Scholar789https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXltVShu7Y%253D&md5=074eaede29f12d54352808f86939b7d6Hydrogenated caged clusters of Si, Ge, and Sn and their endohedral doping with atoms: Ab initio calculationsKumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2007), 75 (15), 155425/1-155425/11CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The stability was studied of hydrogenated empty cages XnHn with X = Si, Ge, and Sn, and n = 8, 10, 12, 14, 16, 18, 20, 24, and 28 using the DFT-GGA and ultrasoft-pseudopotential plane-wave methods. All these cages have large HOMO-LUMO gaps. The HOMO-LUMO gap for Ge cages was found to be even larger than the values for Si cages, though in bulk Ge has a smaller band gap than Si. Cages with n = 16 and 20 were found to be particularly stable in the form of fullerene structures. The bonding in the dodecahedral X20H20 cage is very close to sp3 type and it leads to the highest stability of this cage with perfect icosahedral symmetry. Endohedral doping of the empty cages such as SinHn (n = 10-28), with different guest atoms shows that doping can be used to manipulate the HOMO-LUMO gap with the possibility of varying their optical properties as well as to prep. species with large magnetic moments. Depending upon the guest atom, the character of the HOMO and the LUMO states and their origins either from the cage or the guest atom changes. This could lead to their applications in sensors. In contrast to the metal-encapsulated silicon-caged clusters, the embedding energy of the guest atom in the hydrogenated silicon fullerenes is small in most cases due to the weak interactions with the cage and therefore these slaved guest atoms can keep their at. properties to a large extent. We find that atoms with closed electronic shell configurations such as Ca, Ba,... generally occupy the center of the cage. However, Be and other open electronic shell atoms tend to drift towards the wall of the cage. Doping with halogens such as iodine and alkalis such as Na can be used to produce, resp. hole and electron doping while transition-metal atoms such as V, Cr, Mn, and Fe were shown to produce at.-like magnetic moments in many cases. In most of these cases the HOMO-LUMO gap becomes small because the guest atom orbital(s) are only partially occupied. However, for Ni and Zn the HOMO-LUMO gap is large as the hybridized d orbitals become fully occupied. An interesting finding was that the endohedral doping can lead to a higher-energy undoped cage isomer to become the lowest-energy doped isomer. Implications of this result for endohedral fullerenes of carbon are also discussed.
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790Bahramy, M. S.; Kumar, V.; Kawazoe, Y. First-principles calculations of hyperfine structure in M-doped Si16H16 fullerene cages (M = Cr, Mn, and Fe). Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 79, 235443, DOI: 10.1103/PhysRevB.79.235443Google Scholar790https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXotFKqu70%253D&md5=d9f4d04341f65a90f9f669e9d405eb5dFirst-principles calculations of hyperfine structure in M-doped Si16H16 fullerene cages (M=Cr, Mn, and Fe)Bahramy, Mohammad Saeed; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2009), 79 (23), 235443/1-235443/7CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We study magnetism and hyperfine structure in Si16H16 fullerenes endohedrally doped with a transition-metal atom M=Cr, Mn, and Fe using d. functional theory calcns. In all cases the endohedral fullerene maintains the same magnetic moment as in a free M atom and it is mainly localized on M with partial redistribution on the Si16H16 cage. However, a comparison between the isotropic hyperfine parameter Aiso of M dopants with that of free M atoms reveals that the electronic wave function at the nucleus of Mn and Fe undergo a significant change both quant. and qual. as they become doped inside Si16H16 cage, while for Cr it remains nearly the same. The endohedral doping of Mn and Fe atoms increases the value of the spin d. at the nucleus of the M atom, ρs(RM) and correspondingly, the value of Aiso. Analyzing the trend of the core spin polarization induced by the singly occupied MOs (SOMOs), it is shown that the increase in the value of Aiso for Mn and Fe atoms comes directly from an increase in the contribution of SOMOs to ρs(RM) and indirectly from hybridization of 3d orbitals of the dopants with the s- and p-like orbitals of the cage. The latter results in a decrease in the spin-polarization of the core 2s and 3s orbitals so that they less effectively contribute to ρs(RM). These results are likely to have wider applicability and could offer a way to identify endohedral doping.
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791Zhao, Y.; Kim, Y.-H.; Dillon, A.; Heben, M.; Zhang, S. Hydrogen storage in novel organometallic buckyballs. Phys. Rev. Lett. 2005, 94, 155504, DOI: 10.1103/PhysRevLett.94.155504Google Scholar791https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjsFGrsb0%253D&md5=fa6661402f3f7f2e2f64a9bc3c46f777Hydrogen Storage in Novel Organometallic BuckyballsZhao, Yufeng; Kim, Yong-Hyun; Dillon, A. C.; Heben, M. J.; Zhang, S. B.Physical Review Letters (2005), 94 (15), 155504/1-155504/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Transition metal (TM) atoms bound to fullerenes are proposed as adsorbents for high d., room temp., ambient pressure storage of H. C60 or C48B12 disperses TMs by charge transfer interactions to produce stable organometallic buckyballs (OBBs). A Sc OBB can bind as many as 11 H atoms per TM, 10 of which are as dihydrogen that can be adsorbed and desorbed reversibly. In this case the calcd. binding energy is ∼0.3 eV/H2, which is ideal for hydrogen storage in vehicles. The theor. max. retrievable H2 storage d. is ∼9%.
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792Yildirim, T.; Ciraci, S. Titanium-decorated carbon nanotubes as a potential high-capacity hydrogen storage medium. Phys. Rev. Lett. 2005, 94, 175501, DOI: 10.1103/PhysRevLett.94.175501Google Scholar792https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvF2nsrw%253D&md5=d422830119d37719d2e29e7729e726fdTitanium-decorated carbon nanotubes as a potential high-capacity hydrogen storage mediumYildirim, T.; Ciraci, S.Physical Review Letters (2005), 94 (17), 175501/1-175501/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report a 1st-principles study, which demonstrates that a single Ti atom coated on a single-walled nanotube (SWNT) binds up to four H mols. The first H2 adsorption is dissociative with no energy barrier while the other three adsorptions are mol. with significantly elongated H-H bonds. At high Ti coverage we show that a SWNT can strongly adsorb up to 8 wt. % hydrogen. These results advance our fundamental understanding of dissociative adsorption of hydrogen in nanostructures and suggest new routes to better storage and catalyst materials.
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793Liang, W.; Jia, J.; Lv, J.; Wu, H. Electronic structure, stability and magnetic properties of small M1–2Cr (M= Fe, Co, and Ni) alloy encapsulated inside a (BN)48 cage. Phys. Lett. A 2015, 379, 1715– 1721, DOI: 10.1016/j.physleta.2015.04.037Google Scholar793https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnvFequ70%253D&md5=fa68ae2225509e896e4c93278ea1cff2Electronic structure, stability and magnetic properties of small M1-2Cr (M = Fe, Co, and Ni) alloy encapsulated inside a (BN)48 cageLiang, Wenjuan; Jia, Jianfeng; Lv, Jin; Wu, HaishunPhysics Letters A (2015), 379 (30-31), 1715-1721CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The geometrical structure and magnetic properties of M1-2Cr (M = Fe, Co, and Ni) alloy clusters inside a (BN)48 cage were calcd. at the BPW91/LANL2DZ level of theory. The doping with Cr significantly changed the magnetic properties of the transition-metal clusters. When M1-2Cr alloys were placed inside a (BN)48 cage, the alloy clusters interacted strongly with the cage, and the M1-2Cr@(BN)48 clusters showed high stability. Moreover, Cr-doped magnetic metal clusters preferably occupied positions off-center and near the hexagonal rings of (BN)48 cages. Thus, the (BN)48 cages can be used to increase the stability of M1-2Cr alloys, and retain their magnetic nature, except for CoCr and Ni2Cr clusters.
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794Burnin, A.; BelBruno, J. J. ZnnSm+ cluster production by laser ablation. Chem. Phys. Lett. 2002, 362, 341– 348, DOI: 10.1016/S0009-2614(02)01105-3Google Scholar794https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmtlWgtrs%253D&md5=4c915254988186e46941f1975efa1c4aZnnS+m cluster production by laser ablationBurnin, Andrei; BelBruno, Joseph J.Chemical Physics Letters (2002), 362 (3,4), 341-348CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Laser ablation of ZnS or mixts. of elemental Zn and S was used to produce clusters. Mass spectrometric detection was used to identify the products. Regardless of the compn. of the ablation sample, mass spectra were dominated by mixed cluster ions. The mass peak corresponding to Zn13S+13 was present in an abundance much greater than its neighbor ions, indicating that the geometry of this particular cluster confers a special stability. The mass spectra of the analogous ZnO clusters did not exhibit magic nos. Structure calcns. were employed to provide a preliminary est. of the possible geometries of this cluster.
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795Kasuya, A.; Sivamohan, R.; Barnakov, Y. A.; Dmitruk, I. M.; Nirasawa, T.; Romanyuk, V. R.; Kumar, V.; Mamykin, S. V.; Tohji, K.; Jeyadevan, B. Ultra-stable nanoparticles of CdSe revealed from mass spectrometry. Nat. Mater. 2004, 3, 99– 102, DOI: 10.1038/nmat1056Google Scholar795https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXoslWqtg%253D%253D&md5=6f2c1cb85b546b484e1dbc5c4ad98799Ultra-stable nanoparticles of CdSe revealed from mass spectrometryKasuya, Atsuo; Sivamohan, Rajaratnam; Barnakov, Yurii A.; Dmitruk, Igor M.; Nirasawa, Takashi; Romanyuk, Volodymyr R.; Kumar, Vijay; Mamykin, Sergiy V.; Tohji, Kazuyuki; Jeyadevan, Balachandran; Shinoda, Kozo; Kudo, Toshiji; Terasaki, Osamu; Liu, Zheng; Belosludov, Rodion V.; Sundararajan, Vijayaraghavan; Kawazoe, YoshiyukiNature Materials (2004), 3 (2), 99-102CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Nanoparticles under a few nanometers in size have structures and material functions that differ from the bulk because of their distinct geometrical shapes and strong quantum confinement. These qualities could lead to unique device applications. The authors' mass spectral anal. of CdSe nanoparticles reveals that (CdSe)33 and (CdSe)34 are extremely stable: with a simple soln. method, they grow in preference to any other chem. compns. to produce macroscopic quantities. First-principles calcns. predict that these are puckered (CdSe)28-cages, with four- and six-membered rings based on the highly sym. octahedral analogs of fullerenes, accommodating either (CdSe)5 or (CdSe)6 inside to form a three-dimensional network with essentially heteropolar sp3-bonding. This is in accordance with the authors' x-ray and optical analyses. The authors found similar mass spectra and at. structures in CdS, CdTe, ZnS and ZnSe, demonstrating that mass-specified and macroscopically produced nanoparticles, which were practically limited so far to elemental C, can now be extended to a vast variety of compd. systems.
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796Kasuya, A.; Noda, Y.; Dmitruk, I.; Romanyuk, V.; Barnakov, Y.; Tohji, K.; Kumar, V.; Belosludov, R.; Kawazoe, Y.; Ohuchi, N. Stoichiometric and ultra-stable nanoparticles of II-VI compound semiconductors. Eur. Phys. J. D 2005, 34, 39– 41, DOI: 10.1140/epjd/e2005-00114-9Google Scholar796https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtFOru7c%253D&md5=9b7722230bf9981793fad69ccd7750c1Stoichiometric and ultra-stable nanoparticles of II-VI compound semiconductorsKasuya, A.; Noda, Y.; Dmitruk, I.; Romanyuk, V.; Barnakov, Y.; Tohji, K.; Kumar, V.; Belosludov, R.; Kawazoe, Y.; Ohuchi, N.European Physical Journal D: Atomic, Molecular and Optical Physics (2005), 34 (1-3), 39-41CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)Nanoparticles of (CdSe)n are found extremely stable at n = 33 and 34 with structures distinctively different from the bulk fragments. They grow exclusively in large amt. with a simple soln. method. The diam. is detd. as 1.5 nm. Such ultra-stable nanoparticles had been predicted both theor. and exptl. after the discovery of C fullerenes, but not been produced macroscopically in any other element or compd. system. First-principles calcns. predict that the structures of (CdSe)33 and (CdSe)34 are puckered (CdSe)28-cages accommodating resp. (CdSe)5 an (CdSe)6 inside to form a three-dimensional network of essentially hetero-polar sp3-bonding.
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797Kukreja, L.; Rohlfing, A.; Misra, P.; Hillenkamp, F.; Dreisewerd, K. Cluster formation in UV laser ablation plumes of ZnSe and ZnO studied by time-of-flight mass spectrometry. Appl. Phys. A: Mater. Sci. Process. 2004, 78, 641– 644, DOI: 10.1007/s00339-003-2272-8Google Scholar797https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhsFyktr8%253D&md5=002c008ce81d6f6ce6aec3dc320f71a0Cluster formation in UV laser ablation plumes of ZnSe and ZnO studied by time-of-flight mass spectrometryKukreja, L. M.; Rohlfing, A.; Misra, P.; Hillenkamp, F.; Dreisewerd, K.Applied Physics A: Materials Science & Processing (2004), 78 (5), 641-644CODEN: APAMFC; ISSN:0947-8396. (Springer-Verlag)The compn. of nitrogen laser (wavelength 337 nm, pulse width 3 ns) induced ablation plumes from ZnSe and ZnO targets was studied at different laser fluences using a time-of-flight mass spectrometer. In the case of ZnSe, abundant ion signals corresponding to Se and ZnSe clusters, some of which were Se-rich, were detected with fluence-dependent distributions. At a laser fluence of 1250 J m-2, clusters with elevated intensity were obsd. at sizes of 6, 13, 19, 23 and 33 ZnSe mols. ( magic nos.), which match quite well with the earlier observation by others of magic nos. of chem. similar ZnS produced by a conventional vaporization and quenching scheme. In the case of ZnO, we detected the presence of at. Zn and mol. species of ZnO, as well as a series of (ZnO)n-type clusters with fluence-dependent distributions. Unlike the case of ZnSe, no magic nos. were obsd. for ZnO.
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798Hamad, S.; Catlow, C. R. A.; Spano, E.; Matxain, J. M.; Ugalde, J. M. Structure and properties of ZnS nanoclusters. J. Phys. Chem. B 2005, 109, 2703– 2709, DOI: 10.1021/jp0465940Google Scholar798https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtVSqtA%253D%253D&md5=cb1f16bd51f3387b2b467cb54352786cStructure and Properties of ZnS NanoclustersHamad, Said; Catlow, C. Richard A.; Spano, Eleonora; Matxain, Jon M.; Ugalde, Jesus M.Journal of Physical Chemistry B (2005), 109 (7), 2703-2709CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)Earlier studies have shown that the most stable structures for (ZnS)n clusters with n = 10-47 are hollow polyhedral clusters ("bubbles"). We report a detailed study of larger clusters, where n = 50, 60, 70, and 80, for which onionlike or "double bubble" structures are predicted. We report calcns. of the vibrational spectra and the electronic structure of bubble and double bubble clusters, which may assist in their exptl. identification.
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799Matxain, J. M.; Eriksson, L. A.; Formoso, E.; Piris, M.; Ugalde, J. M. Endohedral (X@ZniSi)i=4-160,± nanoclusters, X = Li, Na, K, Cl, Br. J. Phys. Chem. C 2007, 111, 3560– 3565, DOI: 10.1021/jp0668697Google Scholar799https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsFOktbY%253D&md5=b9a39a88ee2f1dfd5d2bd643f9e313eeEndohedral (X@ZniSi)1=4-160,± Nanoclusters, X = Li, Na, K, Cl, BrMatxain, Jon M.; Eriksson, Leif A.; Formoso, Elena; Piris, Mario; Ugalde, Jesus M.Journal of Physical Chemistry C (2007), 111 (9), 3560-3565CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Endohedral (X@ZniSi)q (q = -1, 0, 1) structures were calcd. using the DFT-B3LYP method. In these structures, the X atoms are trapped inside previously characterized spheroid hollow structures with pos. charged Zn atoms and neg. charged S atoms. Although the radii of all atoms are similar, Zn atoms are located more inside the structure. The alkali metals are found to be trapped inside a larger no. of spheroid structures than the halogens. The parameters detg. the stability of the endohedral structures are the charge and size of the trapped atom, along with the sphericity of the cluster.
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800Poggio, S.; Wang, B.; Gibson, U. J.; BelBruno, J. J. Properties of transition metal substituted zinc sulfide hexamers and dodecamers. Phys. Chem. Chem. Phys. 2015, 17, 14208– 14214, DOI: 10.1039/C5CP00574DGoogle Scholar800https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnsVaqs7Y%253D&md5=3353d0a7acc67e0194c6496aadd70a99Properties of transition metal substituted zinc sulfide hexamers and dodecamersPoggio, Stefano; Wang, Brendan; Gibson, Ursula J.; BelBruno, Joseph J.Physical Chemistry Chemical Physics (2015), 17 (21), 14208-14214CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)D. functional theory was used to study the structural and electronic properties of endohedrally- and substitutionally-doped Zn6S6 and Zn12S12 clusters with first-row transition metal atoms. Generally, the lowest energy electronic state of the cluster is that with the max. multiplicity (Ti and Cr are exceptions). Substitutionally-doped clusters have greater binding energies (per atom) for both cluster sizes, providing an indication that similar doping will be preferred in the bulk material as well. The results are relevant to thin films of doped ZnS in which cluster formation is likely.
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801Matxain, J. M.; Formoso, E.; Mercero, J. M.; Piris, M.; Lopez, X.; Ugalde, J. M. Magnetic endohedral transition-metal-doped semiconduncting-nanoclusters. Chem. - Eur. J. 2008, 14, 8547– 8554, DOI: 10.1002/chem.200800376Google Scholar801https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht1OgsbvJ&md5=539993d1c35f80204247e078b08bf213Magnetic endohedral transition-metal-doped semiconducting nanoclustersMatxain, Jon M.; Formoso, Elena; Mercero, Jose M.; Piris, Mario; Lopez, Xabier; Ugalde, Jesus M.Chemistry - A European Journal (2008), 14 (28), 8547-8554CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Endohedral 1st-row transition-metal-doped TM@ZniSi nanoclusters, in which TM stands for the 1st-row transition-metals from Sc to Zn, and i = 12, 16, were characterized. In these structures the dopant metals are trapped inside spheroidal hollow semiconducting nanoclusters. Some of the transition metals are trapped in the center of mass of the cluster, whereas others are displaced from that center, leading to structures in which the transition metals display a complex dynamical behavior upon encapsulation. This fact was confirmed by quantum mol. dynamics calcns., which further confirmed the thermal stability of endohedral compds. In the endohedrally-doped nanoclusters in which the transition-metal atom sits on the center of mass, the host hollow cluster structure remains undistorted after dopant encapsulation. Conversely, if the encapsulated transition-metal atom is displaced from the center of mass, the host hollow cluster structure suffers a very tiny distortion. Addnl., there is negligible charge transfer between the dopant transition-metal atom and its hollow cluster host and, after encapsulation, the spin densities remain localized on the transition-metal atom. This allows for the at.-like behavior of the trapped transition-metal atom, which gives rise to their at.-like magnetic properties. The encapsulation free energies are neg., suggesting that these compds. are thermodynamically stable.
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802Jimenez-Izal, E.; Matxain, J. M.; Piris, M.; Ugalde, J. M. Thermal stability of endohedral first-row transition-metal TM@ZniSi structures, i = 12, 16. J. Phys. Chem. C 2011, 115, 7829– 7835, DOI: 10.1021/jp108640wGoogle Scholar802https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXktFenurc%253D&md5=3ee4acf29e7b00ff74fc9a3843cab2e2Thermal Stability of Endohedral First-Row Transition-Metal TM@ZniSi Structures, i = 12, 16Jimenez-Izal, Elisa; Matxain, Jon M.; Piris, Mario; Ugalde, Jesus M.Journal of Physical Chemistry C (2011), 115 (16), 7829-7835CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The thermal stability was studied of first-row transition-metal-doped TM@ZniSi nanoclusters for the two lowest-lying spin states of each metal using DFT-GGA methods (TM stands for the first-row transition metals from Sc to Zn; i = 12, 16). These structures were previously characterized by Matxain et al. The metal atom can move toward the surface of the nanocluster forming the so-called surface-doped structure. The relative energies of two isomers were calcd. We also characterized the transition states connecting both isomers and the energy barriers needed to move from one to another in order to predict the thermal stability of the endohedral compds. These values were further used to predict the lifetimes of the endohedrally doped nanoclusters. Most of the lifetimes were predicted to be very small, although most of them are large enough for exptl. detection. The lifetimes of Zn@Zn12S12 and Zn@Zn16S16 are very large.
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803Jimenez-Izal, E.; Matxain, J.; Piris, M.; Ugalde, J. Second-row transition-metal doping of (ZniSi), i = 12, 16 nanoclusters: Structural and magnetic properties. Computation 2013, 1, 31– 45, DOI: 10.3390/computation1030031Google ScholarThere is no corresponding record for this reference.
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804Chen, H.; Shi, D.; Qi, J.; Wang, B. Structure, electronic and magnetic properties of Cr-doped (ZnS)12 clusters: A first-principles study. Phys. Lett. A 2010, 374, 4133– 4139, DOI: 10.1016/j.physleta.2010.08.030Google Scholar804https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFWiurfP&md5=d63bbb9d63416e0cf4110704433e3e15Structure, electronic and magnetic properties of Cr-doped (ZnS)12 clusters: A first-principles studyChen, Hongxia; Shi, Daning; Qi, Jingshan; Wang, BaolinPhysics Letters A (2010), 374 (40), 4133-4139CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)We have studied the structural, electronic, and magnetic properties of (ZnS)12 clusters doped with one (monodoped) and two (bidoped) Cr atoms in terms of a first-principles method. Substitutional, exohedral, and endohedral doping are considered. The substitutional isomer is found to be most favorable in energy for monodoped clusters, while the exohedral isomers are found to be most favorable for bidoped clusters. The magnetic coupling between the Cr atoms is mainly governed by the competition between direct Cr-Cr antiferromagnetic (AFM) interaction and the ferromagnetic (FM) interaction between two Cr atoms via S atom due to strong p-d hybridization. Finally, we show that the exohedral bidoped (ZnS)12 clusters favor the FM state, which has potential applications in nanoscale quantum devices.
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805Chen, H.; Shi, D.; Qi, J.; Wang, B. First-principles study on the structure, electronic, and magnetic properties of Mn-doped (ZnS)12 clusters. Phys. E 2010, 43, 117– 124, DOI: 10.1016/j.physe.2010.06.027Google Scholar805https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVyhurbM&md5=1015d745e7b8da9aad170e652a2ba6edFirst-principles study on the structure, electronic, and magnetic properties of Mn-doped (ZnS)12 clustersChen, Hongxia; Shi, Daning; Qi, Jingshan; Wang, BaolinPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2010), 43 (1), 117-124CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)A first-principles d. functional investigation has been performed to evaluate the structural, electronic, and magnetic properties of (ZnS)12 clusters doped with one (monodoped) and two (bidoped) Mn atoms. Substitutional, endohedral, and exohedral doping are considered. The substitutional isomers are found to be most favorable in energy for both monodoped and bidoped clusters. For the optimized isomers of the monodoped case, the doping-induced changes of the bond lengths generally are less than 0.03 Å. The total magnetic moment is independent of at. configuration. For the bidoped case, we find that the magnetic coupling between Mn atoms in host cluster depends on their local environment. The cohesion of substitutional bidoped isomers is found to be more sensitive to the magnetic coupling, while the exohedral ones are more sensitive to the chem. bonding. Most importantly, we demonstrate that the endohedral bidoped (ZnS)12 cluster favors the ferromagnetic state, which has potential applications in nanoscale quantum devices.
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806Chen, H.; Shi, D.; Qi, J.; Wang, B. First-principles study on the magnetic properties of transition-metal atoms doped (ZnS)12 cluster. J. Magn. Magn. Mater. 2011, 323, 781– 788, DOI: 10.1016/j.jmmm.2010.10.044Google Scholar806https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhs1SrtrnE&md5=dde285d22c466962c4c576265db0bb0cFirst-principles study on the magnetic properties of transition-metal atoms doped (ZnS)12 clusterChen, Hongxia; Shi, Daning; Qi, Jingshan; Wang, BaolinJournal of Magnetism and Magnetic Materials (2011), 323 (6), 781-788CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)A 1st-principles d. functional study was performed to evaluate the structural, electronic, and magnetic properties of (ZnS)12 doped with one or two transition-metal (TM) atoms (Fe, Co, and Ni). Substitutional- and interstitial-doping are considered. The substitutional isomers are most favorable for Fe-doped clusters, while the interstitial isomers are most favorable for Co- and Ni-doped clusters. Magnetic coupling between the TM atoms at the nearest neighbor position is mainly governed by the competition between direct ferromagnetic and antiferromagnetic interactions between two TM atoms via the S atom due to strong p-d hybridization. The coupling is short-ranged. Most importantly, the Fe and Ni endohedral bi-doped (ZnS)12 clusters favor the ferromagnetic state, which has potential applications in nanoscale quantum devices.
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807Zhang, D.; Chen, L.; Zhang, J.; Miao, X. Theoretical investigation of structural and magnetic properties of ZnnSen (n = 6–13) nanoclusters doped with manganese atoms. J. Am. Ceram. Soc. 2011, 94, 759– 764, DOI: 10.1111/j.1551-2916.2010.04125.xGoogle Scholar807https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXksFOktbs%253D&md5=8914cd24968870807b5cc47f937cc74bTheoretical investigation of structural and magnetic properties of ZnnSen (n = 6-13) nanoclusters doped with manganese atomsZhang, Daoli; Chen, Liangyan; Zhang, Jianbing; Miao, XiangshuiJournal of the American Ceramic Society (2011), 94 (3), 759-764CODEN: JACTAW; ISSN:0002-7820. (Wiley-Blackwell)With the generalized gradient approxn. in first principle all-electron calcns., the lowest energy structures of ZnnSen (n = 6-13) nanoclusters were obtained as the pristine clusters. A no. of configurations and structural isomers of ZnnSen (n = 6-13) nanoclusters doped with single and two Mn atoms were used to investigate the structural and magnetic properties of manganese-doped ZnnSen (n = 6-13) nanoclusters. It arrives at a conclusion that Mn doping does not change the size-dependent oscillating behavior in second-order energy difference of ZnnSen (n = 6-13) nanoclusters, but leads to the decrease of energy gap between LUMO and the HUMO. Energy arguments indicate that Mn atoms prefer to substitute Zn atoms in Mn-doped ZnnSen (n = 6-13) nanoclusters. Owing the Mn-Mn short-ranged super-exchange mechanism, Mn atoms favor to locate at adjacent Zn atom sites in antiferromagnetic states of ZnnSen nanoclusters doped with two Mn atoms.
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808Yadav, M. K.; Sanyal, B.; Mookerjee, A. Structural, electronic and magnetic properties of Cr-doped (ZnTe)12 clusters. J. Magn. Magn. Mater. 2009, 321, 235– 240, DOI: 10.1016/j.jmmm.2008.08.092Google ScholarThere is no corresponding record for this reference.
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809Ghosh, S.; Sanyal, B.; Das, G. Structural, electronic and magnetic properties of Cr-doped Cd12S12 clusters: A density functional investigation. J. Magn. Magn. Mater. 2010, 322, 734– 742, DOI: 10.1016/j.jmmm.2009.10.051Google Scholar809https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjtVKhtw%253D%253D&md5=19f1e9537819e4d8caec661cfbd07b28Structural, electronic and magnetic properties of Cr-doped Cd12S12 clusters: A density functional investigationGhosh, S.; Sanyal, B.; Das, G. P.Journal of Magnetism and Magnetic Materials (2010), 322 (6), 734-742CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)We have carried out first-principles d. functional investigation of Cd12S12 cluster doped with one (monodoped) and two (bidoped) Cr-atoms, to explore the manifestation of novel magnetism in this family of stable II-VI semiconducting clusters. Different types of possible configurations of the dopant e.g. substitutional, exohedral, endohedral and substitutional-exohedral have been considered. Both for monodoped and bidoped clusters, substitutional doping corresponds to the ground state. In case of bidoped clusters, the coupling is found to be short-ranged, that depends on the Cr-Cr sepn. and the local environment. The main competing factors stabilizing ferromagnetic (FM) state in this class of doped nanoclusters are: (a) the FM interaction between two Cr atoms via S atom due to strong p-d hybridization and (b) the short range Cr-Cr direct antiferromagnetic (AFM) interaction. When addnl. hole is introduced in the system by substituting S with P, in substitutional bidoped clusters, FM state is found to be the ground sate.
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810Jimenez-Izal, E.; Matxain, J. M.; Piris, M.; Ugalde, J. M. Structure and stability of the endohedrally doped (X@CdiSi)i=4, 9, 12, 15, 16q=0,±1, X = Na, K, Cl, Br, nanoclusters. J. Phys. Chem. C 2010, 114, 2476– 2483, DOI: 10.1021/jp909357cGoogle Scholar810https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFams7w%253D&md5=453e119b3df2cfa9e07b9717d4901042Structure and Stability of the Endohedrally Doped (X@CdiSi)i=4,9,12,15,16q=0,±1, X = Na, K, Cl, Br, NanoclustersJimenez-Izal, Elisa; Matxain, Jon M.; Piris, Mario; Ugalde, Jesus M.Journal of Physical Chemistry C (2010), 114 (6), 2476-2483CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The endohedral title structures were studied by the DFT-B3LYP method. These nanoclusters were chosen because of their high sphericity, which was known to be one of the parameters detg. the stability of the endohedral nanoclusters, along with the charge and size of the guest atom. In these structures, the atoms are trapped inside previously characterized spheroid hollow structures with pos. charged Cd atoms and neg. charged S atoms. Moreover, although the radii of all atoms are similar, Cd atoms are located more inside the structure. For alkali metals, neutral and cationic endohedral compds. were characterized and, for halogens, neutral and anionic nanoclusters were studied. Some of these guest atoms are trapped in the center of mass of the cluster, while others are displaced from that center leading to structures where the guest atom shows a complex dynamical behavior. This fact was confirmed by quantum mol. dynamics calcns., which further confirmed the thermal stability of these endohedral compds.
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811Poggio, S.; King, J.; BelBruno, J. Properties of transition metal doped cadmium sulfide hexamers and dodecamers. Chem. Phys. Lett. 2015, 640, 106– 111, DOI: 10.1016/j.cplett.2015.10.007Google Scholar811https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12jurzM&md5=9c96e3c11eff34d9ae0fd76a21d403cdProperties of transition metal doped cadmium sulfide hexamers and dodecamersPoggio, Stefano; King, Jonathan; BelBruno, JosephChemical Physics Letters (2015), 640 (), 106-111CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The electronic and geometrical properties of endohedrally and substitutionally doped Cd6S6 and Cd12S12 clusters were analyzed by means of DFT-PBE method. The results are compared to those of ZnS clusters of the same size. There is a clear correlation between CdS and ZnS when doped with the same element due to the chem. interaction between the dopant and its host. This is particularly evident from endohedrally doped Cd6S6. The change in properties across the 3d series in doped CdS clusters is not as great as in ZnS clusters.
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812Shevlin, S.; Guo, Z.; Van Dam, H.; Sherwood, P.; Catlow, C. A.; Sokol, A.; Woodley, S. Structure, optical properties and defects in nitride (III–V) nanoscale cage clusters. Phys. Chem. Chem. Phys. 2008, 10, 1944– 1959, DOI: 10.1039/b719838hGoogle Scholar812https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjvVentL8%253D&md5=a07ded99e7741054200a28b49957b1e9Structure, optical properties and defects in nitride (III-V) nanoscale cage clustersShevlin, S. A.; Guo, Z. X.; van Dam, H. J. J.; Sherwood, P.; Catlow, C. R. A.; Sokol, A. A.; Woodley, S. M.Physical Chemistry Chemical Physics (2008), 10 (14), 1944-1959CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)DFT-GGA calcns. are reported on cage structured BN, AlN, GaN and InN sub- and low nanosize stoichiometric clusters, including two octahedral families of Td and Th symmetry. The structures and energetics are detd., and we observe that BN clusters in particular show high stability with respect to the bulk phase. The cluster formation energy is demonstrated to include a const. term that we attribute to the curvature energy and the formation of six tetragonal defects. The (BN)60 onion double-bubble structure was found to be particularly unstable. In contrast, similar or greater stability was found for double and single shell cages for the other nitrides. The optical absorption spectra have been first characterized by the one-electron Kohn-Sham orbital energies for all compds., after which we concd. on BN where we employed a recently developed time-dependent DFT approach. The one-electron band gaps do not show a strong and consistent size dependency, in disagreement with the predictions of quantum confinement theory. The d. of excited bound states and absorption spectrum have been calcd. for four smallest BN clusters within the first ionization potential cut-off energy. The relative stability of different BN clusters has been further explored by studying principal point defects and their complexes including topol. B-N bond rotational defects, vacancies, antisites and interstitials. The latter have the lowest energy of formation.
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813Kaur, P.; Sekhon, S.; Kumar, V. Empty cage to three-dimensional structural transition in nanoparticles of III-V compound semiconductors: The finding of magic (AlP)13 and (GaP)32. Phys. Rev. B: Condens. Matter Mater. Phys. 2012, 85, 085429, DOI: 10.1103/PhysRevB.85.085429Google Scholar813https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XkslCgtLY%253D&md5=ff28e282b48d364796c1b4449dba80e4Empty cage to three-dimensional structural transition in nanoparticles of III-V compound semiconductors: the finding of magic (AlP)13 and (GaP)32Kaur, Prabhsharan; Sekhon, S. S.; Kumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2012), 85 (8), 085429/1-085429/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Small nanoparticles of III-V compd. semiconductors have often been considered to have open-cage structures. However, using first-principles calcns., we report the finding of a structural transition from empty-cage structures for (AlN)n and (GaN)n nanoparticles up to n = 34 that we studied, to a filled-cage structure for (InN)32. Further, phosphides and arsenides of Al and In have an early transition to three-dimensional (3D) filled-cage structures. Our results show that a 3D (AlP)13 is strongly magic with high binding energy and large highest occupied-LUMO gap. But nanoparticles of GaP show a transition from an empty cage for n = 13 to a strongly magic 3D filled cage for n = 32. The latter has a cage of (GaP)28 and a (GaP)4 squashed cube inside, the atoms on which are well connected with the cage. The bonding characteristics and the reason for structural transition are discussed.
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814Kaur, P.; Sekhon, S.; Kumar, V. Prediction of rock salt structure of (InN)32 nanoparticles from first principles calculations. J. Chem. Phys. 2013, 138, 114310, DOI: 10.1063/1.4795580Google Scholar814https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXktlKksrg%253D&md5=8f8e345210a3be2cd65b6eeaf00c0a3cPrediction of rock salt structure of (InN)32 nanoparticles from first principles calculationsKaur, Prabhsharan; Sekhon, S. S.; Kumar, VijayJournal of Chemical Physics (2013), 138 (11), 114310/1-114310/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)From first principles calcns., we show that (InN)32 nanoparticles favor rock salt structure compared with wurtzite structure in bulk. A phase transition from wurtzite to rock salt structure is known to occur in bulk InN at 12.1 GPa and higher values of pressure for AlN and GaN. However, at the nanoscale it is shown that this structural transition takes place in (InN)32 without applying pressure. The charge asymmetry value "g" and cation/anion size ratio in InN describe very well this behavior. Similar studies on nanoparticles of AlN and GaN as well as a few other binary compds. such as MgS, AgI, ZnO, and CdSe, however, do not show such a transition. The results suggest (InN)32 to be a unique candidate as further calcns. on a few larger size (InN)n nanoparticles show that a filled cage (two shells) (InN)12@(InN)48 structure of (InN)60 has higher binding energy compared with a rock salt structure of (InN)64 leading to the conclusion that other 3D structures are likely to become favorable over rock salt structure for larger sizes. (c) 2013 American Institute of Physics.
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815Kiran, B.; Kandalam, A. K.; Rallabandi, R.; Koirala, P.; Li, X.; Tang, X.; Wang, Y.; Fairbrother, H.; Gantefoer, G.; Bowen, K. (PbS)32: A baby crystal. J. Chem. Phys. 2012, 136, 024317, DOI: 10.1063/1.3672166Google Scholar815https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XmsVeksA%253D%253D&md5=059b75b3b3d0c5570c476e718d9991d3(PbS)32: A baby crystalKiran, B.; Kandalam, Anil K.; Rallabandi, Rameshu; Koirala, Pratik; Li, Xiang; Tang, Xin; Wang, Yi; Fairbrother, Howard; Gantefoer, Gerd; Bowen, KitJournal of Chemical Physics (2012), 136 (2), 024317/1-024317/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Theor. calcns. based on d. functional theory found (PbS)32 to be the smallest cubic cluster for which its inner (PbS)4 core enjoys bulk-like coordination. Cubic (PbS)32 is thus a baby crystal, i.e., the smallest cluster, exhibiting 6-fold coordination, that can be replicated to obtain the bulk crystal. The calcd. dimensions of the (PbS)32 cluster further provide a rubric for understanding the pattern of aggregation when (PbS)32 clusters are deposited on a suitable surface, i.e., the formation of square and rectangular, cryst. nano-blocks with predictable dimensions. Expts. in which mass-selected (PbS)32 clusters were soft-landed onto a highly ordered pyrolytic graphite surface and the resulting aggregates imaged by scanning tunneling microscopy provide evidence in direct support of the computational results. (c) 2012 American Institute of Physics.
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816Ueno, M.; Onodera, A.; Shimomura, O.; Takemura, K. X-ray observation of the structural phase transition of aluminum nitride under high pressure. Phys. Rev. B: Condens. Matter Mater. Phys. 1992, 45, 10123– 10126, DOI: 10.1103/PhysRevB.45.10123Google Scholar816https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38Xis1KisLY%253D&md5=673bc49760e9a5296bc7cbbb97b6d537X-ray observation of the structural phase transition of aluminum nitride under high pressureUeno, M.; Onodera, A.; Shimomura, O.; Takemura, K.Physical Review B: Condensed Matter and Materials Physics (1992), 45 (17), 10123-6CODEN: PRBMDO; ISSN:0163-1829.The III-V compd. AlN was studied under pressure to 30 GPa by x-ray diffraction in a diamond-anvil cell. At 22.9 GPa the wurtzite-to-rocksalt phase transition takes place accompanied by a vol. redn. of 17.9%. The axial ratio c/a in the wurtzite phase monotonically decreases with increasing pressure from the atm. value of 1.60.
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817Ueno, M.; Yoshida, M.; Onodera, A.; Shimomura, O.; Takemura, K. Stability of the wurtzite-type structure under high pressure: GaN and InN. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 49, 14– 21, DOI: 10.1103/PhysRevB.49.14Google Scholar817https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsV2nu74%253D&md5=9d168f4804a8e62cda695e9667b1a2ddStability of the wurtzite-type structure under high pressure: GaN and InNUeno, Masaki; Yoshida, Minoru; Onodera, Akifumi; Shimomura, Osamu; Takemura, KenichiPhysical Review B: Condensed Matter and Materials Physics (1994), 49 (1), 14-21CODEN: PRBMDO; ISSN:0163-1829.High-pressure in situ x-ray-diffraction studies on GaN and InN were carried out using an imaging-plate technique and a diamond-anvil cell up to about 60 GPa. The 2 compds. crystallize in the wurtzite-type structure at ambient conditions. The axial ratio c/a of GaN remains unchanged from the ambient value of 1.626 whereas c/a of InN is considerably decreased from 1.613 to 1.597 with increasing pressure to about 15 GPa. Equation-of-state data obtained for the wurtzite phase have yielded the bulk modulus of GaN to be 237(31) GPa and that of InN to be 125.5(4.6) GPa. Structural phase transition into the rocksalt-type structure takes place in GaN at 52.2 GPa and in InN at 12.1. The trend in the transition pressures of the III-V nitrides is discussed in terms of various ionicity scales.
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818Wang, J.; Ma, L.; Zhao, J.; Wang, G.; Chen, X.; Bruce King, R. Electronic and magnetic properties of manganese and iron-doped GanAsn nanocages (n = 7–12). J. Chem. Phys. 2008, 129, 044908, DOI: 10.1063/1.2960625Google Scholar818https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptlOisr8%253D&md5=3e5457ad223e2c23dcbed717a0319374Electronic and magnetic properties of manganese and iron-doped GanAsn nanocages (n=7-12)Wang, Jianguang; Ma, Li; Zhao, Jijun; Wang, Guanghou; Chen, Xiaoshuang; King, R. BruceJournal of Chemical Physics (2008), 129 (4), 044908/1-044908/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic and magnetic properties of Mn- or Fe-doped GanAsn (n = 7-12) nanocages were studied using gradient-cor. d.-functional theory considering doping at substitutional, endohedral, and exohedral sites. When doped with one atom, the most energetically favorable site gradually moves from surface (n = 7-11) to interior (n = 12) sites for the Mn atom, while the most preferred doping site of the Fe atom alternates between the surface (n = 7,9,11) and interior (n = 8,10,12) sites. All of the ground-state structures of Mn@anAsn have the atomlike magnetic moment of 5 μB, while the total magnetic moments of the most stable Fe@anAsn cages for each size are ∼2 μB except for the 4 μB magnetic moment of Fe@a12As12. Charge transfer and hybridization between the 4s and 3d states of Mn or Fe and the 4s and 4p states of As were found. The antiferromagnetic (AFM) state of Mn2@anAsn is more energetically favorable than the ferromagnetic (FM) state. However, for Fe2@anAsn the FM state is more stable than the AFM state. The local magnetic moments of Mn and Fe atoms in the GanAsn cages are ∼4 μB and 3 μB in the FM and AFM states, resp. For both Mn and Fe bidoping, the most energetically favorable doping sites of the transition metal atoms are located on the surface of the GanAsn cages. The computed magnetic moments of the doped Fe and Mn atoms agree excellently with the theor. and exptl. values in the Fe(Mn)/GaAs interface as well as (Ga, Mn)As dil. magnetic semiconductors. (c) 2008 American Institute of Physics.
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819Lu, P.; Wu, C.; Li, Y.; Yu, Z.; Cao, H.; Wang, S. Investigation on structural, electronic, and magnetic properties of Mn-doped Ga12N12 clusters. J. Mater. Sci. 2013, 48, 8552– 8558, DOI: 10.1007/s10853-013-7674-1Google Scholar819https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlalu7nE&md5=3e745da6a6b8f66260027a62814115ccInvestigation on structural, electronic, and magnetic properties of Mn-doped Ga12N12 clustersLu, Pengfei; Wu, Chengjie; Li, Yiluan; Yu, Zhongyuan; Cao, Huawei; Wang, ShuminJournal of Materials Science (2013), 48 (24), 8552-8558CODEN: JMTSAS; ISSN:0022-2461. (Springer)The structural, electronic, and magnetic properties of Ga12N12 cluster doped with monodoped and bidoped Mn atoms were investigated based on the d. functional theory. Substitutional, exohedral, and endohedral configurations are considered. The substitutional doping is found to be most favorable for monodoped clusters, while the bidoped clusters prefer the exohedral isomers. For all the isomer, the magnetic moment is mainly derived from 3d orbitals of Mn atom. The exohedral and endohedral bidoped Ga12N12 clusters all favor antiferromagnetic state.
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820Lu, P.; Wu, C.; Cong, Z.; Li, Y.; Zhang, X.; Yu, Z.; Cao, H. Fe-doped Ga12N12 clusters: Electronic and magnetic properties. Mod. Phys. Lett. B 2013, 27, 1350222, DOI: 10.1142/S0217984913502229Google Scholar820https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVWgtrnE&md5=d0995cf7a6cf8ddbd86c71f96bbc1311Fe-doped Ga12N12 clusters: electronic and magnetic propertiesLu, Pengfei; Wu, Chengjie; Cong, Zixiang; Li, Yiluan; Zhang, Xianlong; Yu, Zhongyuan; Cao, HuaweiModern Physics Letters B (2013), 27 (30), 1350222/1-1350222/10CODEN: MPLBET; ISSN:0217-9849. (World Scientific Publishing Co. Pte. Ltd.)In this paper, we have investigated the structural, electronic and magnetic properties of Ga12N12 cluster doped with monodoped and bidoped Fe atoms within the d. functional theory (DFT). Substitutional, exohedral and endohedral doping are considered. It is obsd. that both monodoped and bidoped clusters tend to be in exohedral doping. Mulliken population anal. is performed to obtain the charge transfer and magnetic moment. The magnetic moment is mainly derived from 3d orbitals of Fe atom for all isomers, while the magnetic properties would rely on the Fe-Fe distance.
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821Longo, R.; Carrete, J.; Aguilera-Granja, F.; Vega, A.; Gallego, L. A density-functional study of the structures and electronic properties of neutral, anionic, and endohedrally doped InxPx clusters. J. Chem. Phys. 2009, 131, 074504, DOI: 10.1063/1.3206844Google Scholar821https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVCksr3K&md5=78eed945b2ec7ad003a9d1472219f9ffA density-functional study of the structures and electronic properties of neutral, anionic, and endohedrally doped InxPx clustersLongo, R. C.; Carrete, J.; Aguilera-Granja, F.; Vega, A.; Gallego, L. J.Journal of Chemical Physics (2009), 131 (7), 074504/1-074504/11CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report extensive ab initio calcns. of the structures, binding energies, and magnetic moments of InxPx and InxPx‾ clusters (x = 1-15) using a d.-functional method that employs linear combinations of pseudoat. orbitals as basis sets, nonlocal norm-conserving pseudopotentials, and the generalized gradient approxn. for exchange and correlation. Our results, which are compared with those obtained previously for some of these clusters by means of all-electron calcns., show that hollow cages with alternating In-P bonds are energetically preferred over other structures for both the neutral and anionic species within the range x = 6-15. We also consider the endohedrally doped X@In10P10 (X = Cr,Mn,Fe,Co) and Ti@InxPx (x = 7-12) clusters. Our results show that, except for Ti@In7P7 and Ti@In8P8, the transition metal atoms preserve their at. spin magnetic moments when encapsulated in the InP cages, instead of suffering either a spin crossover or a spin quenching due to hybridization effects. We also show that the stabilities of some empty and doped InP cages can be explained on the basis of the jellium model. (c) 2009 American Institute of Physics.
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822Ding, J.-N.; Yuan, N.-Y.; Li, C.-L.; Wang, X.-Q.; Chen, G.-G.; Chen, X.-S.; Lu, W. Studies on structures, electronic and magnetic properties of TM-doped InnSbn (n = 7–12, 14, 16) clusters (TM = Mn, Fe, and Co). J. Appl. Phys. 2011, 109, 014322, DOI: 10.1063/1.3531533Google Scholar822https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmsFCksA%253D%253D&md5=b753ca248bbe338e47edb00deb4c5c06Studies on structures, electronic and magnetic properties of TM-doped InnSbn (n = 7-12,14,16) clusters (TM = Mn, Fe, and Co)Ding, Jian-Ning; Yuan, Ning-Yi; Li, Chang-Lin; Wang, Xiu-Qin; Chen, Guang-Gui; Chen, Xiao-Shuang; Lu, WeiJournal of Applied Physics (2011), 109 (1), 014322/1-014322/7CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)We study the geometric, electronic, and magnetic properties of the title clusters the DFT-PBE method. For single-atom doping, three doping modes (substitutional, endohedral, and exohedral) were considered. The doped clusters are magnetic except Co-doped In7Sb7 and Co-doped In14Sb14. The lowest energy configurations of TM2In16Sb16 clusters are ferromagnetic (FM) with the TM atoms at the nearest neighbor position; the coupling between the TM atoms is mainly governed by the FM interaction via TM-TM direct interaction. The hybridization between Mn 3d state and the Sb 5p state is also favorable to the stability of FM state. (c) 2011 American Institute of Physics.
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823Liu, C.; Tkachenko, N. V.; Popov, I. A.; Fedik, N.; Min, X.; Xu, C. Q.; Li, J.; McGrady, J. E.; Boldyrev, A. I.; Sun, Z. M. Structure and bonding in [Sb@In8Sb12]3– and [Sb@In8Sb12]5–. Angew. Chem., Int. Ed. 2019, 58, 8367– 8371, DOI: 10.1002/anie.201904109Google Scholar823https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXptlOgtrk%253D&md5=fb32af7ae6cc13922f06ba1d03df4f00Structure and Bonding in [Sb@In8Sb12]3- and [Sb@In8Sb12]5-Liu, Chao; Tkachenko, Nikolay V.; Popov, Ivan A.; Fedik, Nikita; Min, Xue; Xu, Cong-Qiao; Li, Jun; McGrady, John E.; Boldyrev, Alexander I.; Sun, Zhong-MingAngewandte Chemie, International Edition (2019), 58 (25), 8367-8371CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors report the characterization of [K([2.2.2]crypt)]4[In8Sb13], which proves to contain a 1:1 mixt. of [Sb@In8Sb12]3- and [Sb@In8Sb12]5-. The tri-anion displays perfect Th symmetry, the 1st completely inorg. mol. to do so, and contains eight equiv. In3+ centers in a cube. The gas-phase potential energy surface of the penta-anion has eight equiv. min. where the extra pair of electrons is localized on one In+ center, and these min. are linked by low-lying transition states where the electron pair is delocalized over two adjacent centers. The best fit to the electron d. was obtained from a model where the structure of the 5- cluster lies close to the gas-phase transition state.
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824Wang, B.; Nagase, S.; Zhao, J.; Wang, G. Structural growth sequences and electronic properties of zinc oxide clusters (ZnO)n (n = 2-18). J. Phys. Chem. C 2007, 111, 4956– 4963, DOI: 10.1021/jp066548vGoogle Scholar824https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXisF2iuro%253D&md5=c8028972bac7175e986fa9b594590286Structural Growth Sequences and Electronic Properties of Zinc Oxide Clusters (ZnO)n (n=2-18)Wang, Baolin; Nagase, Shigeru; Zhao, Jijun; Wang, GuanghouJournal of Physical Chemistry C (2007), 111 (13), 4956-4963CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structural and electronic properties of (ZnO)n (n = 2-18) clusters were studied using gradient-cor. d.-functional theory (DFT). The starting structures were generated from empirical genetic algorithm simulations or intuitive constructions. The lowest-energy structures of (ZnO)n were then selected from a no. of structural isomers via DFT optimization. For small clusters (n = 2-7), ring structures were found to be the most stable. Three-dimensional cage and tube structures become energetically preferable for larger clusters (n = 9-18), and the competition between cage and tube structures leads to the alternative appearance of these two types of structures as global min. The size evolution of electronic properties for zinc oxide clusters from ring toward cage or tube is discussed.
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825Liu, H.; Wang, S.; Zhou, G.; Wu, J.; Duan, W. Structural, electronic, and magnetic properties of manganese-doped Zn12O12 clusters: A first-principles study. J. Chem. Phys. 2006, 124, 174705, DOI: 10.1063/1.2194015Google Scholar825https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XksFChsbs%253D&md5=90e5f089cb2ee2509d34f63f089b9535Structural, electronic, and magnetic properties of manganese-doped Zn12O12 clusters: A first-principles studyLiu, Haitao; Wang, Shanying; Zhou, Gang; Wu, Jian; Duan, WenhuiJournal of Chemical Physics (2006), 124 (17), 174705/1-174705/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A first-principles study has been performed to evaluate the structural, electronic, and magnetic properties of Zn12O12 clusters doped with one or two Mn atoms. The substitutional, exohedral, and endohedral dopings are taken into account. For the monodoped clusters, the substitutional isomer is most energetically favorable, and an exohedral isomer may appear as a low-lying metastable state. All isomers present 5 μB magnetic moment that is mainly contributed by the Mn-3d component. For the bidoped clusters, the antiferromagnetic state is degenerate with the ferromagnetic state at larger Mn-Mn distance (>5 A), while it is more energetically favorable at smaller Mn-Mn distance. Thus, the cohesion of bidoped isomer is sensitive to the magnetic coupling or chem. bonding. The endohedral bidoped isomer is found to be a stable local min., and the direct Mn-Mn interaction causes the redn. of local magnetic moment of Mn to about 4 μB.
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826Liu, H.; Zhang, J.-M. Investigation on structure, electronic and magnetic properties of Cr doped (ZnO)12 clusters: First-principles calculations. Phys. E 2018, 99, 51– 57, DOI: 10.1016/j.physe.2018.01.014Google Scholar826https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitVegtb8%253D&md5=77ba58174faaf098690e5c00f4949af7Investigation on structure, electronic and magnetic properties of Cr doped (ZnO)12 clusters: First-principles calculationsLiu, Huan; Zhang, Jian-MinPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2018), 99 (), 51-57CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)The structural, electronic, and magnetic properties of (ZnO)12 clusters doped with Cr atoms have been investigated by using spin-polarized first-principles calcns. The exohedral a3 isomer is favorable than endohedral a2 isomer. The isomer a1 and a5 resp. have the narrowest and biggest gap between highest unoccupied MO and the LUMO (HOMO-LUMO) of 0.473 and 1.291 eV among these five monodoped isomers. The magnetic moment may be related to the local environment around the Cr atom that the a2 isomer whose total magnetic moment is 6 μB while the other monodoped isomers which all isomers have nearly total magnetic moments 4 μB. For Cr-doped (ZnO)12 on a1 or a3 isomer, the DOS of spin-up channel cross the Fermi level EF showing a finite magnitude near the Fermi level which might be useful for half metallic character. For the bidoped cases, the exohedral isomers are found to be most favorable. Including all bipoed isomers of substitutional, exohedral and endohedral bidoped clusters, the total magnetic moment of the ferromagnetic (antiferromagnetic) state is 8 (0) μB and the HOMO-LUMO gap of antiferromagnetic state is slightly larger than that of ferromagnetic state. The magnetic coupling between the Cr atoms in bidoped configurations is mainly governed by the competition between direct Cr and Cr atoms antiferromagnetic interaction and the ferromagnetic interaction between two Cr atoms via O atom due to strong p-d hybridization. Most importantly, we show that the exohedral bidoped (ZnO)12 clusters favor the ferromagnetic state, which may have the future applications in spin-dependent magneto-optical and magneto-elec. devices.
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827Baei, M. T.; Peyghan, A. A.; Bagheri, Z. First principles study on encapsulation of alkali metals into ZnO nanocage. Chin. J. Chem. Phys. 2012, 25, 671– 675, DOI: 10.1088/1674-0068/25/06/671-675Google Scholar827https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtVWiu7Y%253D&md5=2e69f1ab93270af13e6b86fb7b9198bdFirst principles study on encapsulation of alkali metals into ZnO nanocageBaei, Mohammad T.; Peyghan, Ali Ahmadi; Bagheri, ZarghamChinese Journal of Chemical Physics (2012), 25 (6), 671-675, 5 pp.CODEN: CJCPA6; ISSN:1674-0068. (Chinese Physical Society)Encapsulation of alkali metals (Li, Na, K and Rb) into Zn12O12 nanocage has been investigated using d. functional theory. Encapsulation of Li and Na atoms is found to be thermodynamically favorable at 298 K and 100 kPa, with neg. Gibbs free energy change ΔG of about -130.12 and -68.43 kJ/mol, resp. By increasing the size of encapsulated atom the process become less favorable so that in the cases of K and Rb encapsulations the ΔG values are pos. The results indicate that the LUMO, Fermi level and specially HOMO of the cluster are shifted to higher energies so that the HOMO-LUMO gap of the cluster is significantly narrowed in all the cases. After encapsulation of the alkali metals the work function of cluster is decreased due to the shift of the Fermi level to higher energies. Therefore, the emitted electron c.d. from the Zn12O12 cluster will be increased.
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828Nanavati, S. P.; Sundararajan, V.; Mahamuni, S.; Ghaisas, S.; Kumar, V. Discovery of a nonstoichiometric Zn11MnSe13 magnetic magic quantum dot from ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 84, 045306, DOI: 10.1103/PhysRevB.84.045306Google Scholar828https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpslGnsrs%253D&md5=3939be016521dbbc68f714d2b17e7322Discovery of a nonstoichiometric Zn11MnSe13 magnetic magic quantum dot from ab initio calculationsNanavati, Sachin P.; Sundararajan, Vijayaraghavan; Mahamuni, Shailaja; Ghaisas, S. V.; Kumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2011), 84 (4), 045306/1-045306/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Ab initio calcns. on ZnSe quantum dots (QDs) doped with one Mn atom have predicted a new nonstoichiometric magnetic magic Zn11MnSe13 structure in contrast to QDs of undoped ZnSe that are stoichiometric and exhibit magic behavior for ZnnSen with n = 13 and 34. Such doping would lead to a high abundance of only one specie (the magic QD) that would be produced preferentially. The stoichiometric Znn-1MnSen QDs have a large magnetic moment of 5 μB that is predominantly localized on the Mn site. The nonstoichiometric QD has a reduced magnetic moment of 3 μB due to strong covalent bonding of the Mn atom with the excess Se atom and a small gap between the HOMO and the LUMO. Charging this magic QD with two electrons leads to a large HOMO-LUMO gap of 1.8 eV and 5 μB magnetic moment.
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829Shakerzdeh, E.; Tahmasebi, E.; Shamlouei, H. R. The influence of alkali metals (Li, Na and K) interaction with Be12O12 and Mg12O12 nanoclusters on their structural, electronic and nonlinear optical properties: A theoretical study. Synth. Met. 2015, 204, 17– 24, DOI: 10.1016/j.synthmet.2015.03.008Google Scholar829https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVCnu7g%253D&md5=f04b71f70e38fb36adf3fef2ec997424The influence of alkali metals (Li, Na and K) interaction with Be12O12 and Mg12O12 nanoclusters on their structural, electronic and nonlinear optical properties: A theoretical studyShakerzdeh, Ehsan; Tahmasebi, Elham; Shamlouei, Hamid RezaSynthetic Metals (2015), 204 (), 17-24CODEN: SYMEDZ; ISSN:0379-6779. (Elsevier B.V.)D. functional theory (DFT) calcns. have been carried out to study the influence of alkali metals (Li, Na and K) interaction with Be12O12 and Mg12O12 nanoclusters on their structural, electronic and nonlinear optical properties. The interaction of Li, Na and K atoms is found to be remarkably narrowed the HOMO-LUMO gaps of the considered clusters. The electronic properties of these clusters are strongly sensitive to interaction with the alkali metals. Moreover, the encapsulation of alkali metals inside of the considered clusters slightly enhances their hyperpolarizabilities with one exception. The encapsulation of Li atom inside of the Mg12O12 nanocluster is energetically favorable and leads to a large hyperpolarizability. Furthermore, the adsorption of the alkali metals on the surface of the considered nanoclusters is investigated. The alkali metals adsorption on the surfaces of the clusters is energetically favorable and causes extremely large nonlinear optical (NLO) response in comparison to encapsulated forms. Therefore, the interaction of alkali metals with Be12O12 and Mg12O12 nanoclusters plays an important role in tuning their electronic and nonlinear optical properties. This work theor. devises novel multifunctional inorg. metal oxide-based nanostructures via interaction with alkali atoms, which could be promoted their potential applications in electronic devices and high-performance NLO materials.
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830Groh, M. F.; Müller, U.; Isaeva, A.; Ruck, M. Ionothermal syntheses, crystal structures, and chemical bonding of the rhodium-centered clusters [RhBi9]4+ and [(RhBi7)I8]. Z. Anorg. Allg. Chem. 2017, 643, 1482– 1490, DOI: 10.1002/zaac.201700242Google Scholar830https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsV2rt7jE&md5=e3e85a6ef98e5b6c747d26e4b7b208e6Ionothermal Syntheses, Crystal Structures, and Chemical Bonding of the Rhodium-Centered Clusters [RhBi9]4+ and [(RhBi7)I8]Groh, Matthias F.; Mueller, Ulrike; Isaeva, Anna; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2017), 643 (21), 1482-1490CODEN: ZAACAB; ISSN:1521-3749. (Wiley-VCH Verlag GmbH & Co. KGaA)The first filled Bi95+ polycation was isolated in the form of [RhBi9](AlCl4)4 crystals by dissoln. of the solid precursor Bi12-xRhX13-x in the Lewis-acidic ionic liq. [BMIm]Cl·3.6AlCl3 (BMIm = 1-butyl-3-methylimidazolium) at 140 °C. In the monoclinic crystal structure [P21/n, a = 1217.5(2) pm, b = 1741.6(3) pm, c = 5085.7(7) pm, β = 90.117(8)°], the almost spherical [RhBi9]4+ polycations (approx. D3h symmetry; Rh-Bi 276 ± 3 pm) show pronounced orientational disorder. Shiny black needles of Bi7RhI8 were obtained from the reaction of rhodium, bismuth, and BiI3 in the ionic liq. [BMIm]Cl·1.3AlCl3 at 200 °C. Bi7RhI8 [P21/n, a = 943.10(1) pm, b = 1582.40(1) pm, c = 1645.40(1) pm, β = 95.48(1)°] is isostructural to Bi7RhBr8 and consists of mol. clusters [(RhBi7)I8]. The rhodium atom centers a pentagonal bipyramid of bismuth atoms, and the two apical bismuth atoms are in square-planar coordination of iodide ions. DFT-based calcns. indicate strong bismuth-rhodium bonding with predominantly covalent character for both clusters. The electronic structure of the Bi95+ cage is notably modified by this interaction, but the characteristic bonding features of the host cluster with the D3h configuration are still maintained. In Bi7RhI8, on the other hand, bonding is dictated by the spatial distribution of mutually repelling iodine atoms, and the Bi-Rh bonding is highly polar.
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831Ruck, M.; Dubenskyy, V.; Söhnel, T. Structure and bonding of Pd@[Bi10]4+ in the subbromide Bi14PdBr16. Angew. Chem., Int. Ed. 2003, 42, 2978– 2982, DOI: 10.1002/anie.200250801Google Scholar831https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXlslGks7g%253D&md5=453c763d1dacb6f29b927013f96bbd29Structure and bonding of Pd@[Bi10]4+ in the subbromide Bi14PdBr16Ruck, Michael; Dubenskyy, Vitaly; Soehnel, TiloAngewandte Chemie, International Edition (2003), 42 (26), 2978-2982CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The bismuth palladium subbromide Bi14PdBr16 was prepd. and characterized by x-ray crystallog. Bi14PdBr16 is comprised of the cationic cluster [PdBi10]4+, a pentagonal antiprism of ten Bi atoms with a Pd atom in the center, and polymeric 1∞[BiBr4-] anions. Quantum mech. calcns. were performed on the bonding of Bi14PdBr16 and the isolated cluster cation [PdBi10]4+.
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832Dubenskyy, V.; Ruck, M. Das subchlorid Bi16PdCl22: Pd@Bi104+-polykationen in einem raumnetzwerk aus chlorobismutat(III)-anionen. Z. Anorg. Allg. Chem. 2004, 630, 2458– 2462, DOI: 10.1002/zaac.200400206Google Scholar832https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXpslelu7c%253D&md5=7d1b527284f40205fc6dacafc7ff34e0The subchloride Bi16PdCl22. Pd@Bi104+ polycations inside a framework of chloro-bismuthate(III) anionsDubenskyy, Vitaly; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2004), 630 (13-14), 2458-2462CODEN: ZAACAB; ISSN:0044-2313. (Wiley-VCH Verlag GmbH & Co. KGaA)Black, air-sensitive crystals of Bi16PdCl22 were synthesized from the elements by cooling melts slowly from 1270 K to room temp. X-ray diffraction on single-crystals revealed that the compd. crystallizes with the triclinic space group P‾1 and lattice parameters a = 2047.7(4) pm, b = 2132.1(4) pm, c = 2145.4(4) pm, α = 91.09(3)°, β = 95.14(3)°, γ = 93.16(3)°, dc = 6.034, 25,371 obsd. reflections with Fo > 4σ(Fo), 1417 refined parameters, R1 = 0.029, wR2 = 0.086 (all data) . In the crystal structure polycations Pd@Bi104+ with the shape of pentagonal Archimedean antiprisms (D5d symmetry) are embedded in the cavities of a pseudo-cubic framework 3∞[Bi6Cl22]4- formed by chloro-bismuthate(III) anions that share vertices and edges. The 2×2×2 superstructure results from 3 different main orientations of the polycations occurring with ratio 3:3:2. The weak interaction between the interstitial closed-shell Pd0 and the electron-precise arachno-cluster Bi104+ is represented by the formulation as a cationic inclusion compd. Pd@Bi104+.
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833Groh, M. F.; Wolff, A.; Wahl, B.; Rasche, B.; Gebauer, P.; Ruck, M. Pentagonal bismuth antiprisms with endohedral palladium or platinum atoms by low-Temperature syntheses. Z. Anorg. Allg. Chem. 2017, 643, 69– 80, DOI: 10.1002/zaac.201600354Google Scholar833https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVSiurnE&md5=3e7c1bc712cfb51ba9a2240a3fd7d37dPentagonal Bismuth Antiprisms with Endohedral Palladium or Platinum Atoms by Low-Temperature SynthesesGroh, Matthias F.; Wolff, Alexander; Wahl, Bernhard; Rasche, Bertold; Gebauer, Paul; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2017), 643 (1), 69-80CODEN: ZAACAB; ISSN:1521-3749. (Wiley-VCH Verlag GmbH & Co. KGaA)Authors present the syntheses, crystal structures, and properties of five metal-rich salts contg. the Bi104+ pentagonal antiprism with an endohedral palladium or, for the first time, platinum atom. Tetragonal [Pt@Bi10](AlBr4)4 [P42/n at 296(1) K; P4 at 150(2) K] was obtained by reacting platinum, bismuth, and bismuth tribromide in [BMIm]Br·4.1AlBr3 at 140° (BMIm = 1-butyl-3-methylimidazolium). Monoclinic [Pt@Bi10](AlBr4)2(Al2Br7)2 [P21/n] occurs as byproduct. The two corresponding palladium compds. result from the dissoln. of Bi16PdCl22 in [BMIm]Br·4.1AlBr3. [Pd@Bi10](AlBr4)4 [P42/n] adopts a disordered structure homeotypic to its platinum analog. [Pd@Bi10](AlBr4)2(Al2Br7)2 [P21/n] is isostructural to [Pt@Bi10](AlBr4)2(Al2Br7)2. In all structures, the [M@Bi10]4+ cations are well sepd. by the bromido-aluminate anions with inter-cluster Bi···Bi distances longer than 520 pm. This is not the case in [Pd@Bi10][Bi2Sn6Cl22], which crystd. from a tin-contg. melt of the metals and BiCl3. In its monoclinic structure [P21/c], the cluster cations are arranged in chains along [001] with an inter-cluster distance of only 357 pm. Despite further structural evidence, DFT-based quantum chem. anal. gave no hint on inter-cluster bonding. According to the calcd. band structure as well as resistivity and magnetic susceptibility measurements, the black compd. is a diamagnetic semiconductor.
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834Wahl, B.; Erbe, M.; Gerisch, A.; Kloo, L.; Ruck, M. Nobel-metal centered polycations [Au@Bi10]5+ or [Pd@Bi10]4+ embedded in halogenido-bismuthate(III)-stannate(II) frameworks. Z. Anorg. Allg. Chem. 2009, 635, 743– 752, DOI: 10.1002/zaac.200900087Google Scholar834https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlslGku78%253D&md5=70b170042a1a9f723bcb203f3fa5f664Nobel-metal centered polycations [Au@Bi10]5+ or [Pd@Bi10]4+ embedded in halogenido-bismuthate(III)-stannate(II) frameworksWahl, Bernhard; Erbe, Manuela; Gerisch, Alexander; Kloo, Lars; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2009), 635 (4-5), 743-752CODEN: ZAACAB; ISSN:0044-2313. (Wiley-VCH Verlag GmbH & Co. KGaA)The metal-rich halides AuBi14-δSn2+δX21-δ (δ ≈ 0.4) and PdBi15-δSn1+δX21-δ(δ ≈ 0.6) with X = Cl, Br were crystd. from melts of the metals and BiX3. In the rhombohedral structures (space group R‾3; a ≈ 1050 pm; α ≈ 94°), noble-metal centered pentagonal antiprisms [Au@Bi10]5+ resp. [Pd@Bi10]4+ are embedded in halometalate frameworks 3∞[Bi4-δSn2+δX21-δ]5- resp. 3∞[Bi5-δSn1+δX21-δ]4-. Mixed BiIII/SnII site occupation allows the framework to adopt different charges. Further exchange of BiIIIX3 against SnIIX2 results in vacancies (6) on the position of an isolated halide ion. In quantum chem. calcns. the naked metal-clusters are stable in D5d symmetry with interat. distances close to the obsd. ones. The significance of interactions between the Wade-type host cluster Bi104++ and the closed-subshell guest atoms Au+ or Pd0 is reflected in the MO diagram, the population analyses and the ELI-D.
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835Lichtenberger, N.; Wilson, R. J.; Eulenstein, A. R.; Massa, W.; Clérac, R.; Weigend, F.; Dehnen, S. Main group metal–actinide magnetic coupling and structural response upon U4+ inclusion into Bi, Tl/Bi, or Pb/Bi cages. J. Am. Chem. Soc. 2016, 138, 9033– 9036, DOI: 10.1021/jacs.6b04363Google Scholar835https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFeku7zN&md5=d61c1009779c82c455c6a0060f19695cMain Group Metal-Actinide Magnetic Coupling and Structural Response Upon U4+ Inclusion Into Bi, Tl/Bi, or Pb/Bi CagesLichtenberger, Niels; Wilson, Robert J.; Eulenstein, Armin R.; Massa, Werner; Clerac, Rodolphe; Weigend, Florian; Dehnen, StefanieJournal of the American Chemical Society (2016), 138 (29), 9033-9036CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The encapsulation of actinide ions in intermetalloid clusters has long been proposed but was never realized synthetically. The authors report the isolation and exptl., as well as quantum chem., characterization of the U-centered clusters [U@Bi12]3-, [U@Tl2Bi11]3-, [U@Pb7Bi7]3-, and [U@Pb4Bi9]3-, upon reaction of (EE'Bi2)2- (E = Ga, Tl, E' = Bi; E = E' = Pb) and [U(C5Me4H)3] or [U(C5Me4H)3Cl] in 1,2-diaminoethane. For [U@Bi12]3-, magnetic susceptibility measurements rationalize an unprecedented antiferromagnetic coupling between a magnetic U4+ site and a unique radical Bi127- shell.
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836Lips, F.; Clérac, R.; Dehnen, S. [Eu@Sn6Bi8]4–: A mini-fullerane-type zintl anion containing a lanthanide ion. Angew. Chem., Int. Ed. 2011, 50, 960– 964, DOI: 10.1002/anie.201005655Google Scholar836https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmslOrsw%253D%253D&md5=834d12c6b97dd35b0be5fa256ba56ce5[Eu@n6Bi8]4-: A Mini-Fullerane-Type Zintl Anion Containing a Lanthanide IonLips, Felicitas; Clerac, Rodolphe; Dehnen, StefanieAngewandte Chemie, International Edition (2011), 50 (4), 960-964, S960/1-S960/41CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The reaction of [K([2.2.2]crypt)]2[Sn2Bi2]·en with [(C5Me4H)3Eu] yields [K([2.2.2]crypt)]4[Eu@Sn6Bi8]·1.1en (1) as extremely air sensitive brown crystals which were characterized by ESI-MS and EDX anal. The crystal structure of 1 shows that the [Eu@Sn6Bi8]4- anion consists of a fullerene-like Sn6Bi8 cage having 6 pentagonal and 3 square faces with an endohedral Eu ion. The magnetic properties of 1 were studied along with comprehensive quantum chem. investigations using DFT. The data support the existence of divalent Eu(II), and thus the Zintl anion exists as a [Sn6Bi8]6- shell. The DFT calcd. relative stabilities of various topol. isomers of the Sn6Bi8 cage were detd. DFT investigations were also performed on the hypothetical C14 fullerene and the C14H14 fullerane for comparison.
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837Lips, F.; Hołynska, M.łg.; Clerac, R.; Linne, U.; Schellenberg, I.; Pottgen, R.; Weigend, F.; Dehnen, S. Doped semimetal clusters: Ternary, intermetalloid anions [Ln@Sn7Bi7]4– and [Ln@Sn4Bi9]4– (Ln = La, Ce) with adjustable magnetic properties. J. Am. Chem. Soc. 2012, 134, 1181– 1191, DOI: 10.1021/ja209226bGoogle Scholar837https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFejtb3J&md5=7504c7e15622bac16ee02d2c9cd0a126Doped Semimetal Clusters: Ternary, Intermetalloid Anions [Ln@Sn7Bi7]4- and [Ln@Sn4Bi9]4- (Ln = La, Ce) with Adjustable Magnetic PropertiesLips, Felicitas; Holynska, Malgorzata; Clerac, Rodolphe; Linne, Uwe; Schellenberg, Inga; Poettgen, Rainer; Weigend, Florian; Dehnen, StefanieJournal of the American Chemical Society (2012), 134 (2), 1181-1191CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Two K([2.2.2]crypt) salts of lanthanide-doped semimetal clusters were prepd., both of which contain at the same time two types of ternary intermetalloid anions, [Ln@Sn7Bi7]4- and [Ln@Sn4Bi9]4-, in 0.70:0.30 (Ln = La) or 0.39:0.61 (Ln = Ce) ratios. The cluster shells represent nondeltahedral, fullerane-type arrangements of 14 or 13 main group metal atoms that embed the Ln3+ cations. The assignment of formal +III oxidn. states for the Ln sites was confirmed by magnetic measurements that reveal a diamagnetic La(III) compd. and a paramagnetic Ce(III) analog. Whereas the cluster anions with a 14-at. main-group metal cage represent the second examples in addn. to a related Eu(II) cluster published just recently, the 13-at. cages exhibit a yet unprecedented enneahedral topol. In contrast to the larger cages, which accord to the Zintl-Klemm-Busmann electron no.-structure correlation, the smaller clusters require a more profound interpretation of the bonding situation. Quantum chem. investigations served to shed light on these unusual complexes and showed significant narrowing of the HOMO-LUMO gap upon incorporation of Ce3+ within the semimetal cages.
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838Ababei, R.; Massa, W.; Weinert, B.; Pollak, P.; Xie, X.; Clérac, R.; Weigend, F.; Dehnen, S. Ionic-radius-driven selection of the main-group-metal cage for intermetalloid clusters [Ln@PbxBi14–x]q– and [Ln@PbyBi13–y]q– (x/q = 7/4, 6/3; y/q = 4/4, 3/3). Chem. - Eur. J. 2015, 21, 386– 394, DOI: 10.1002/chem.201404904Google Scholar838https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFGgtLrJ&md5=ccf1b1371517ac3d100b2ad7f8608292Ionic-Radius-Driven Selection of the Main-Group-Metal Cage for Intermetalloid Clusters [Ln@PbxBi14-x]q- and [Ln@PbyBi13-y]q- (x/q = 7/4, 6/3; y/q = 4/4, 3/3)Ababei, Rodica; Massa, Werner; Weinert, Bastian; Pollak, Patrik; Xie, Xiulan; Clerac, Rodolphe; Weigend, Florian; Dehnen, StefanieChemistry - A European Journal (2015), 21 (1), 386-394CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Reactions of the binary, pseudo-homoat. Zintl anion (Pb2Bi2)2- with Ln(C5Me4H)3 (Ln = La, Ce, Nd, Gd, Sm, Tb) in the presence of [2.2.2]crypt in ethane-1,2-diamine/toluene yielded ten [K([2.2.2]crypt)]+ salts of lanthanide-doped semimetal clusters with 13 or 14 surface atoms. Single-crystal x-ray diffraction and energy-dispersive X-ray spectroscopy indicated the presence of [Ln@Pb6Bi8]3-, [Ln@Pb3Bi10]3-, [Ln@Pb7Bi7]4-, or [Ln@Pb4Bi9]4- in single or double salts; the latter showed various ratios of the components in the solid state. The anions are the first ternary intermetalloid clusters comprising only elements of the sixth period of the periodic table, namely, Pb, Bi and lanthanides. This study, which was complemented by ESI mass spectrometry and 139La NMR spectroscopy in soln., rationalizes a continuous development of the ratio of 13:14-atom cages with the ionic radius of the embedded Ln3+ ion, which seems to select the most suitable cage type. Quantum chem. studies helped to analyze this situation in more detail and to explain the obsd. subtle influence of the at. radii. Magnetic measurements confirmed that the embedded Ln3+ ions keep their expected paramagnetic or diamagnetic nature.
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839Mitzinger, S.; Broeckaert, L.; Massa, W.; Weigend, F.; Dehnen, S. [V@Ge8As4]3– and [Nb@Ge8As6]3–: Encapsulation of electron-poor transition metal atoms. Chem. Commun. 2015, 51, 3866– 3869, DOI: 10.1039/C4CC10086GGoogle Scholar839https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFeqtL0%253D&md5=635c475373b92543861317bde0f7f569[V@Ge8As4]3- and [Nb@Ge8As6]3-: encapsulation of electron-poor transition metal atomsMitzinger, Stefan; Broeckaert, Lies; Massa, Werner; Weigend, Florian; Dehnen, StefanieChemical Communications (Cambridge, United Kingdom) (2015), 51 (18), 3866-3869CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)[K([2.2.2]crypt)]+ salts of [V@Ge8As4]3- and [Nb@Ge8As6]3- were obtained by extn. of quaternary phases with en/[2.2.2]crypt. The V-Ge-As anion is the first Zintl anion incorporating a (formal) V5+ cation, thus the smallest cation ever embedded within a main group (semi-)metal cage. It represents the second example of a novel 12-vertex cluster architecture. The bonding situation was elucidated by quantum chem., also allowing for a precise assignment of Ge vs. As atoms, being indistinguishable by x-ray diffraction.
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840Mitzinger, S.; Broeckaert, L.; Massa, W.; Weigend, F.; Dehnen, S. Understanding of multimetallic cluster growth. Nat. Commun. 2016, 7, 10480, DOI: 10.1038/ncomms10480Google Scholar840https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhtl2gsr8%253D&md5=7487b0e392426e4da104dc508532bc4cUnderstanding of multimetallic cluster growthMitzinger, Stefan; Broeckaert, Lies; Massa, Werner; Weigend, Florian; Dehnen, StefanieNature Communications (2016), 7 (), 10480CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)The elucidation of formation mechanisms is mandatory for understanding and planning of synthetic routes. For (bio-)org. and organometallic compds., this has long been realized even for very complicated mols., whereas the formation of ligand-free inorg. mols. has widely remained a black box to date. This is due to poor structural relationships between reactants and products and the lack of structurally related intermediates-due to the comparably high coordination flexibility of involved atoms. Here we report on investigations of the stepwise formation of multimetallic clusters, based on a series of crystal structures and complementary quantum-chem. studies of (Ge2As2)2-, (Ge7As2)2-, [Ta@Ge6As4]3-, [Ta@Ge8As4]3- and [Ta@Ge8As6]3-. The study makes use of efficient quantum-chem. tools, enabling the first detailed screening of the energy hypersurface along the formation of ligand-free inorg. species for a semi-quant. picture. The results can be generalized for an entire family of multimetallic clusters.
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841Lips, F.; Dehnen, S. Neither electron-precise nor in accordance with Wade–Mingos rules: The ternary cluster anion [Ni2Sn7Bi5]3–. Angew. Chem., Int. Ed. 2011, 50, 955– 959, DOI: 10.1002/anie.201005496Google Scholar841https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmslOqtA%253D%253D&md5=5c5a19175372b586c8e6210874644bddNeither Electron-Precise nor in Accordance with Wade-Mingos Rules: The Ternary Cluster Anion [Ni2Sn7Bi5]3-Lips, Felicitas; Dehnen, StefanieAngewandte Chemie, International Edition (2011), 50 (4), 955-959, S955/1-S955/34CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The ternary Zintl intermetalloid cluster anion, [K([2.2.2]crypt)]3[Ni2Sn7Bi5] (I), was prepd. from [K([2.2.2]crypt)]2[Sn2Bi2]·en (en = 1,2-ethylenediamine) and Ni(cod)2 (cod = 1,5-cyclooctadiene) in 15% yield. I was characterized by x-ray crystallog., ESI mass spectrometry and DFT investigation. Relative energies of all isomers of a given compn. [Ni2Sn12-xBix]3- for x = 0-12 were calcd. to find the most stable isomer of compd. I.
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842Wilson, R. J.; Hastreiter, F.; Reiter, K.; Büschelberger, P.; Wolf, R.; Gschwind, R. M.; Weigend, F.; Dehnen, S. [Co@Sn6Sb6]3–: An off-center endohedral 12-vertex cluster. Angew. Chem., Int. Ed. 2018, 57, 15359– 15363, DOI: 10.1002/anie.201807180Google Scholar842https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitVWqsrfL&md5=2355e6b610ead3f31259ebcd2c580836[Co@Sn6Sb6]3-: An Off-Center Endohedral 12-Vertex ClusterWilson, Robert J.; Hastreiter, Florian; Reiter, Kevin; Bueschelberger, Philipp; Wolf, Robert; Gschwind, Ruth M.; Weigend, Florian; Dehnen, StefanieAngewandte Chemie, International Edition (2018), 57 (47), 15359-15363CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Authors report on the asym. occupation of a 12-vertex cluster centered by a single metal atom. Three salts of related intermetalloid cluster anions, [Co@Sn6Sb6]3- (1), [Co2@Sn5Sb7]3- (2), and [Ni2@Sn7Sb5]3- (3) were synthesized, which have pseudo-C4v-sym. or pseudo-D4h-sym. 12-vertex Sn/Sb shells and interstitial Co- ions or Ni atoms. Anion 1 is a very unusual single-metal-"centered" 12-atom cluster, with the inner atom being clearly offset from the cluster center for energetic reasons. Quantum chem. served to assign atom types to the at. positions and relative stabilities of this cluster type. The studies indicate that the structures are strictly controlled by the total valence electron count-which is particularly variable in ternary intermetalloid cluster anions. Preliminary 119Sn NMR studies in soln., supported by quantum-chem. calcns. of the shifts, illustrate the complexity regarding Sn:Sb distributions of such ternary systems.
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843Lips, F.; Clerac, R.; Dehnen, S. [Pd3Sn8Bi6]4–: A 14-vertex Sn/Bi cluster embedding a Pd3 triangle. J. Am. Chem. Soc. 2011, 133, 14168– 14171, DOI: 10.1021/ja203302tGoogle Scholar843https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVOnsrzO&md5=50076ab03810978a98c85d42587c377f[Pd3Sn8Bi6]4-: A 14-Vertex Sn/Bi Cluster Embedding a Pd3 TriangleLips, Felicitas; Clerac, Rodolphe; Dehnen, StefanieJournal of the American Chemical Society (2011), 133 (36), 14168-14171CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The endohedral cluster anion [Pd3Sn8Bi6]4- crystallizes as its K([2.2.2]crypt)+ salt 1 upon reaction of [K([2.2.2]crypt)]2[Sn2Bi2]·en and Pd(dppe)2 in 1,2-diaminoethane (en)/toluene and incorporates a complete Pd3 triangular cluster within a medium-size 14-vertex cage of Sn and Bi atoms. 1 Was characterized by a combination of single crystal diffraction, ESI mass spectrometry, elemental anal., and magnetic measurements. According to quantum chem. studies, the Pd3 triangle interacts only weakly with the Sn/Bi cluster shell despite the relatively small cavity inside the cage.
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844Pham, H. T.; Nguyen, M. T. Theoretical investigation of metallic heterofullerenes of silicon and germanium mixed with phosphorus and arsenic atoms M-A8E6, A = Si, Ge; E = P, As; and M = Cr, Mo, W. J. Phys. Chem. A 2017, 121, 5056– 5066, DOI: 10.1021/acs.jpca.7b04631Google Scholar844https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpvVSqtrY%253D&md5=b3fd46b12b603a74362681c53471b6c3Theoretical Investigation of Metallic Heterofullerenes of Silicon and Germanium Mixed with Phosphorus and Arsenic Atoms M-A8E6, A = Si, Ge; E = P, As; and M = Cr, Mo, WPham, Hung Tan; Nguyen, Minh ThoJournal of Physical Chemistry A (2017), 121 (26), 5056-5066CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Recently, metallic heterofullerenes were exptl. prepd. from mixed Ge-As clusters and heavier elements of groups 14 and 15. We found that the shape of these heterofullerenes doped by transition metals appears to be a general structural motif for both silicon and germanium clusters when mixing with phosphorus and arsenic atoms. Structural identifications for MSi8P6, MSi8As6, MGe8P6,and MGe8As6 clusters, with M being a transition metal of group 6(Cr, Mo and W), showed that most MA8E6 clusters, except for Cr-doped derivs. CrSi8As6, CrGe8P6, and CrGe8As6, exhibit a high symmetry fullerene shape in which metal dopant is centered in a D3h A8E6 heterocage consisting of six A3E2 pentagonal faces and three A2E2 rhombus faces. The stability of the MA8E6 metallic heterofullerene is significantly enhanced by formation an electron configuration of [1S2 1P6 1D10 1F14 1G18 2S2 2P6 2D10]. The A8E6 heterocages give a great charge transfer (∼4 electrons) to centered dopant, establishing subsequently a d10 configuration for metal, and as a consequence, it induces an addnl. stabilization of the resulting ME8P6 fullerene in a high symmetry D3h shape and completely quenches the high spin of the metal atom, finally yielding a singlet spin ground state.
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845Tam, N. M.; Pham, H. T.; Cuong, N. T.; Tung, N. T. A DFT investigation on geometry and chemical bonding of isoelectronic Si8N6V–, Si8N6Cr, and Si8N6Mn+ clusters. Chem. Phys. Lett. 2017, 685, 410– 415, DOI: 10.1016/j.cplett.2017.08.009Google ScholarThere is no corresponding record for this reference.
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846Song, B.; Zhou, J.; Yong, Y.; He, P. Density functional investigation of transition-metal-encapsulated SinCn (n = 7–10) cagelike clusters. J. Phys. Chem. C 2010, 114, 10703– 10710, DOI: 10.1021/jp100745fGoogle Scholar846https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvF2qsbs%253D&md5=4c34a6aeb51477b3899ece2242c3c56bDensity Functional Investigation of Transition-Metal-Encapsulated SinCn (n = 7-10) Cagelike ClustersSong, Bin; Zhou, Jun; Yong, Yongliang; He, PimoJournal of Physical Chemistry C (2010), 114 (24), 10703-10710CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The geometries, stabilities, and electronic and magnetic properties of 3d and 4d transition-metal (TM)-encapsulated SinCn (n = 7-10) cagelike clusters were systematically investigated using the d. functional theory with generalized gradient approxn. SinCn cagelike structures doped with TM atoms are stable, esp. when they encapsulate 3d (or 4d) TM atoms. The formation of an endohedral structure strongly depends on the TM atom present and the SinCn cage size. Among the SinCn cages studied, the Si8C8 cage is the energetically optimal cage for encapsulating most of the 3d and 4d TM atoms. For TM@Si8C8, 3d and 4d TM dopants exhibit similar electronic and magnetic behaviors. The electronic properties of the TM@Si8C8 clusters are characterized by electron transfer from silicon and carbon atoms to TM atoms. The total magnetic moments of TM@Si8C8 clusters oscillate from 0 to 1 μB across the periodic table. The total magnetic moments are mainly located on the 3s and 3p states of Si atoms, and the 2p states of C atoms and TM atoms contribute the least.
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847Pham, H. T.; Nguyen, H. T.; Nguyen, M. T. Mn@B3N3Si8+: A stable singlet manganese-doped hetero-atom-mixed silicon fullerene. Struct. Chem. 2017, 28, 1887– 1893, DOI: 10.1007/s11224-017-0973-4Google Scholar847https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXptVahsr0%253D&md5=9d320dce83d3bb87bd7d15a0ce435642Mn@B3N3Si8+: a stable singlet manganese-doped hetero-atom-mixed silicon fullerenePham, Hung Tan; Nguyen, Huyen Thi; Nguyen, Minh ThoStructural Chemistry (2017), 28 (6), 1887-1893CODEN: STCHES; ISSN:1040-0400. (Springer)A B3N3Si8 cage is formed upon substitution of Si sites of rhombus faces of the pure Si14 cluster by B and N atoms. Doping by the ion Mn+ leads to the hetero-silicon fullerene B3N3Si8Mn+ which comprises three rhombi (BNBN, Si3B and Si3N) and four pentagons (two Si2B2N and two Si2BN2). Hetero-atoms form polarized Si-N and Si-B bonds as indicated by electron localization function (ELF) maps and NBO charges. The Mn center connects the B3N3Si8 cage by ionic interactions. Valence electrons of B3N3Si8Mn+ occupy a shell configuration of [1S2 1P6 1D10 1F14 1G12 2S2 2P6 2D10] and induce a certain thermodn. stability. The high spin of the Mn+ metal cation is completely quenched within the hetero-Si fullerene.
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848King, R. B.; Zhao, J. The isolable matryoshka nesting doll icosahedral cluster [As@Ni12@As20]3- as a ″superatom″: Analogy with the jellium cluster Al13- generated in the gas phase by laser vaporization. Chem. Commun. 2006, 4204– 4205, DOI: 10.1039/B607895HGoogle Scholar848https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVCru7jJ&md5=d6c4558e9ed27624ee364ad6f895888cThe isolable matryoshka nesting doll icosahedral cluster [As@Ni12@As20]3- as a "superatom": analogy with the jellium cluster Al13- generated in the gas phase by laser vaporizationKing, R. Bruce; Zhao, JijunChemical Communications (Cambridge, United Kingdom) (2006), (40), 4204-4205CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The valence electrons in the recently reported icosahedral cluster [As@Ni12@As20]3- with a Russian matryoshka nesting doll structure can be partitioned so that the central As atom has the rare gas configuration, as As3-, and the intermediate Ni12 icosahedron receives 40 electrons from the lone pairs of the outer As20 dodecahedron to be isoelectronic with the Al13- jellium cluster found in mol. beam expts.
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849Sheong, F. K.; Chen, W. J.; Kim, H.; Lin, Z. Peeling the onion: A revised model of the electron count for matryoshka clusters. Dalton Trans. 2015, 44, 7251– 7257, DOI: 10.1039/C5DT00097AGoogle Scholar849https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjvF2rsrc%253D&md5=f96be01c93f0907c1fc9cadd50072bb6Peeling the onion: a revised model of the electron count for matryoshka clustersSheong, Fu Kit; Chen, Wen-Jie; Kim, Hwon; Lin, ZhenyangDalton Transactions (2015), 44 (16), 7251-7257CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)We have provided a model for understanding two isoelectronic matryoshka clusters, [Sn@Cu12@Sn20]12- and [As@Ni12@As20]3-. By dividing each of the clusters in a layer-by-layer manner and allowing each layer to follow a simple electron-filling rule, we can formulate a consistent model to explain exptl. and computed properties of both matryoshka clusters that cannot be adequately explained by existing models. By analyzing these clusters in a way analogous to peeling an onion, we can not only have an understanding of the structure and bonding of the two matryoshka clusters under study, but also have a generalizable model to handle certain p/d-block@d-block endohedral clusters.
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850Baruah, T.; Zope, R. R.; Richardson, S. L.; Pederson, M. R. Electronic structure and rebonding in the onionlike As@Ni12@As20 cluster. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 241404, DOI: 10.1103/PhysRevB.68.241404Google Scholar850https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmvVahtA%253D%253D&md5=c4824a713f3fd35ebaeb1f62069c962eElectronic structure and rebonding in the onionlike As@Ni12@As20 clusterBaruah, Tunna; Zope, Rajendra R.; Richardson, Steven L.; Pederson, Mark R.Physical Review B: Condensed Matter and Materials Physics (2003), 68 (24), 241404/1-241404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We present the ab initio study of the geometry, electronic structure, charged states, bonding, and vibrational modes of the recently synthesized fullerene-like As@Ni12@As20 cluster which has icosahedral point symmetry [M. J. Moses, J. C. Fettinger, and B. W. Eichhorn, Science, 300, 778 (2003)]. The mol. is vibrationally stable and will be electronically most stable in its -3 oxidn. state in the condensed phase and in -2 state in the gas phase. We examine the bonding in this unusually structured mol. from charge transfer between atoms, IR and Raman spectra, and charge-d. isosurfaces.
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851Baruah, T.; Zope, R. R.; Richardson, S. L.; Pederson, M. R. Electronic structure, vibrational stability, and predicted infrared-Raman spectra of the As20, As@Ni12, and As@Ni12@As20 clusters. J. Chem. Phys. 2004, 121, 11007– 11015, DOI: 10.1063/1.1803539Google Scholar851https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVCqtr7O&md5=add147fa69f1b633332d64c38e52a96eElectronic structure, vibrational stability, and predicted infrared-Raman spectra of the As20, As@Ni12, and As@Ni12@As20 clustersBaruah, Tunna; Zope, Rajendra R.; Richardson, Steven L.; Pederson, Mark R.Journal of Chemical Physics (2004), 121 (22), 11007-11015CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Recently an inorg. fulleride-like [As@Ni12@As20]3- onion with near-perfect icosahedral symmetry in the cryst. phase was reported [M. J. Moses, J. C. Fettinger, and B. W. Eichhorn, Science 300, 778(2003)]. This paper presents a detailed computational study in the framework of d. functional theory on various aspects of this mol. The electronic structure of the As@Ni12@As20 is studied in its neutral as well as -3 charged state together with its subunits As20 and As@Ni12 by the all electron linear combination of Gaussian-type orbitals method. The bonding is studied by examg. the integrated charge within at. sphere, the electron localization function, changes in the electron d. distribution, and from vibrational modes. Strong covalent As-As bonds seen in isolated As20 become weaker in the As@Ni12@As20 and strong covalent As-Ni bonds are formed. The structural stability of all 4 clusters is examd. by analyzing the energetics and by calcg. the vibrational frequencies. Further, the IR and Raman spectra is predicted for both the neutral and charged As@Ni12@As20 clusters. Finally, the energy barrier for removal of a single As atom is calcd. for the neutral As@Ni12@As20 cluster.
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852Zhao, J.; Xie, R.-H. Density functional study of onion-skin-like [As@Ni12As20]3– and [Sb@Pd12Sb20]3– cluster ions. Chem. Phys. Lett. 2004, 396, 161– 166, DOI: 10.1016/j.cplett.2004.07.121Google Scholar852https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnsVGqt7o%253D&md5=b385058e13a5075b046fcb04bf83800bDensity functional study of onion-skin-like [As@Ni12As20]3- and [Sb@Pd12Sb20]3- cluster ionsZhao, Jijun; Xie, Rui-HuaChemical Physics Letters (2004), 396 (1-3), 161-166CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)A comprehensive study of the structural and electronic properties of the interesting onion-skin-like [As@Ni12As20]3- cluster ion, characterized by Moses et al. [Science 300 (2003) 778], was carried out using a plane-wave based d. functional theory. The calcd. interat. distances agree well with expt. The HOMO and LUMO for [As@Ni12As20]3- are fivefold-degenerate with hu and hg symmetries, resp., and its HOMO-LUMO gap is detd. to be 0.2 eV lower than that of C60. The static dipole polarizability of [As@Ni12As20]3- is two times larger than that of C60. The optical gap of [As@Ni12As20]3- is red shifted by 1.4 eV relative to that of C60. The possibility of synthesis of [Sb@Pd12Sb20]3- is proposed.
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853Chang, C.; Patzer, A. B. C.; Sedlmayr, E.; Sülzle, D. Inorganic cage molecules encapsulating Kr: A computational study. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 72, 235402, DOI: 10.1103/PhysRevB.72.235402Google Scholar853https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlvFyltA%253D%253D&md5=1b367599ed958480776f5ad8f5b64349Inorganic cage molecules encapsulating Kr: A computational studyChang, Ch.; Patzer, A. B. C.; Sedlmayr, E.; Sulzle, D.Physical Review B: Condensed Matter and Materials Physics (2005), 72 (23), 235402/1-235402/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Structural and energetic properties of a series of neutral and charged inorg. cage mols. Kr@2@20q (Y = Ni,Pd; Z = As,Sb,Bi; q = 0,-1,-3) where a central krypton atom is encapsulated by two outer cages Y12 and Z20 have been investigated by theor. d. functional techniques (DFT) employing the Becke-Perdew-86 (BP86) gradient cor. exchange correlation functional. The structures are closed shell species representing highly stable local min. of icosahedral point group symmetry Ih. We report energies, equil. geometric parameters, selected harmonic vibrational frequencies, and discuss static elec. dipole polarizabilities. The overall charge q of these cages seems to be controllable by the nature of the central atom leading to stable configurations when Kr is replaced by Br or As. In this context, we report a stable system where a krypton atom is enclosed by a fullerenelike inorg. double cage.
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854Chang, C.; Patzer, A. B. C.; Sedlmayr, E.; Sülzle, D.; Steinke, T. Onion-like inorganic fullerenes of icosahedral symmetry. Comput. Mater. Sci. 2006, 35, 387– 390, DOI: 10.1016/j.commatsci.2004.07.013Google Scholar854https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1OitrjK&md5=8d053f0bef6106112e72369db7985956Onion-like inorganic fullerenes of icosahedral symmetryChang, Ch.; Patzer, A. B. C.; Sedlmayr, E.; Suelzle, D.; Steinke, T.Computational Materials Science (2006), 35 (3), 387-390CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)We report a theor. d. functional study (DFT/BP86/LANL2DZ) of a class of inorg. clusters of formal compn. [X@Y12@Z20]α, which all possess high icosahedral point group symmetry (Ih) consisting of a central atom (X) surrounded by two polyhedral cages: an inner core icosahedron (Y) and an outer shell fullerene-like dodecahedron (Z). All species considered are energetically stable closed-shell systems having a metal/semi-metal compn. Energetic and optimized structural properties as well as a full frequency anal. are presented.
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855Huang, X.; Zhao, J.; Su, Y.; Chen, Z.; King, R. B. Design of three-shell icosahedral Matryoshka clusters A@B12@A20 (A = Sn, Pb; B = Mg, Zn, Cd, Mn).. Sci. Rep. 2015, 4, 6915, DOI: 10.1038/srep06915Google ScholarThere is no corresponding record for this reference.
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856King, R. B. Chemical applications of topology and group theory.31. Atomic orbital graphs and the shapes of the g and h orbitals. J. Phys. Chem. A 1997, 101, 4653– 4656, DOI: 10.1021/jp970985fGoogle Scholar856https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXjs1Wls7k%253D&md5=9e6d0f01113db569f8b24abe732e2094Chemical Applications of Topology and Group Theory. 31. Atomic Orbital Graphs and the Shapes of the g and h OrbitalsKing, R. B.Journal of Physical Chemistry A (1997), 101 (25), 4653-4656CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)AOs, which are described by the quantum nos. n, l, and m, can be depicted by an orbital graph in which the vertices correspond to the lobes of the AOs and the edges to nodes between adjacent lobes of opposite sign. The orbital graph for the unique orbital with m = 0 for a given value of l consists of a linear graph with l + 1 vertices. The orbital graphs for the pair of orbitals with m = ±l consist of polygons with 2l vertices. The orbital graphs for the remaining 2(l - 1) orbitals with 0 < |m| < l consist of a stack of l + 1 - |m| polygons each with |2m| vertices. For a given value of l the AOs with |m| = k and |m'| = l + 1 - k have the same nos. of lobes. Orbital graphs are useful for understanding not only the shapes of AOs of high nodality but also the shapes of the MOs in mols. approximated by a sphere such as the C60 fullerene.
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857Zhang, L.; Huang, J.; Wang, W. Y.; Li, Q. X.; Yang, J. L. Transport properties of a three-shell icosahedral matryoshka cluster: A first-principles study. RSC Adv. 2017, 7, 12704– 12710, DOI: 10.1039/C7RA01003FGoogle Scholar857https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjt1antrc%253D&md5=6f52b1f51cdebf6609b37a2921b41e0aTransport properties of a three-shell icosahedral matryoshka cluster: a first-principles studyZhang, Lu; Huang, Jing; Wang, Weiyi; Li, Qunxiang; Yang, JinlongRSC Advances (2017), 7 (21), 12704-12710CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Extensive efforts have been devoted to explore transport behaviors through various mols. and clusters, which are promising building blocks in mol. electronics. Here, we examine the spin-polarized electronic structures and transport properties of a three-shell icosahedral matryoshka cluster, Pb@Mn12@Pb20, by performing d. functional theory calcns. combining with non-equil. Green's function method. Theor. results clearly reveal that, twelve Mn atoms in the middle layer anti-ferromagnetically couple with the center Pb atom and Pb atoms in the outlayer, while the Pb@Mn12@Pb20 cluster still has a huge magnetic moment of 28.0μB, mainly contributed by these Mn atoms. The calcd. spin-resolved transmission spectra of the proposed Pb@Mn12@Pb20 junctions exhibit robust spin filtering effect, which is not sensitive to the anchoring distance and the adopted electrode materials, and the conductance through the cluster under the small bias voltage is mainly detd. by the spin-up electrons. These findings indicate that this kind of three-shell matryoshka cluster with huge magnetic moment holds potential applications in mol. spintronic devices.
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858Long, F.; Liu, H.; Li, D.; Yan, J. Spin-orbit coupling effects on ligand-free icosahedral Matryoshka superatoms. J. Phys. Chem. A 2017, 121, 2420– 2428, DOI: 10.1021/acs.jpca.6b12186Google Scholar858https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjt1Grs7s%253D&md5=b1a64bf33f861986038f356b25f3ba2dSpin-Orbit Coupling Effects on Ligand-Free Icosahedral Matryoshka SuperatomsLong, Feiyun; Liu, Haitao; Li, Dafang; Yan, JunJournal of Physical Chemistry A (2017), 121 (12), 2420-2428CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)With the help of d. functional theory, a series of matryoshka superatoms X@Y12@X20 (X = Ge, Y = Zn; X = Sn, Y = Mg, Mn, Zn or Cd; X = Pb, Y = Mg, Mn, Cd, Zn or Hg) with icosahedral symmetry has been extensively studied, to focus on the influence of the spin-orbit coupling on geometries, stabilities, electronic structures and magnetic moments for these clusters. Generally speaking, the effect of spin-orbit coupling is highly correlated with compn. elements of these clusters. Ge@Zn12@Ge20 is little affected by the spin-orbit coupling, while clusters contg. Sn atom will generally undergo a moderate influence on their atomization energy, HOMO-LUMO gap and projected d. of states. For clusters with Pb atoms, the effect of spin-orbit coupling could be obsd. distinctly in most cases. Our results demonstrate that the spin-orbit coupling can play a substantial role in superatoms contg. heavy elements.
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859MacLeod Carey, D.; Morales-Verdejo, C.; Muñoz-Castro, A. [As@Ni12@As20]3– and [Sn@Cu12@Sn20]12– clusters. Related structures with different construction philosophy. Chem. Phys. Lett. 2015, 638, 99– 102, DOI: 10.1016/j.cplett.2015.08.039Google Scholar859https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlyls7jL&md5=7872c58476ba373444fa20f9ae355bed[As@Ni12@As20]3- and [Sn@Cu12@Sn20]12- clusters. Related structures with different construction philosophyMacLeod Carey, Desmond; Morales-Verdejo, Cesar; Munoz-Castro, AlvaroChemical Physics Letters (2015), 638 (), 99-102CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)[Sn@Cu12@Sn20]12- and [As@Ni12@As20]3- structures display highly spherical shapes according to A@B12@A20. Their anal. denote similar features in the electronic structure construction, however the resulting charge distribution exhibits large differences accounting for the different electronic requirements of such concentric structures. This leads to different electronic distribution in the overall system, where the compn. of relevant electronic shells and charge distribution in the whole cluster is an important point to take into account in addn. to well developed electron count rules.
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860Rauhalahti, M.; Munoz-Castro, A. Interaction in multilayer clusters: A theoretical survey of [Sn@Cu12@Sn20]12-, a three-layer matryoshka-like intermetalloid. RSC Adv. 2015, 5, 18782– 18787, DOI: 10.1039/C4RA16660DGoogle Scholar860https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXit1Gjs7Y%253D&md5=20ded0070ff82aecd2dcc844898d0f22Interaction in multilayer clusters: a theoretical survey of [Sn@Cu12@Sn20]12-, a three-layer matryoshka-like intermetalloidRauhalahti, Markus; Munoz-Castro, AlvaroRSC Advances (2015), 5 (24), 18782-18787CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)[Sn@Cu12@Sn20]12- represents an archetypal intermetalloid structure composed of several concentric polyhedral shells displaying a highly spherical shape. This feature paves the way to understanding the electronic structure of multilayered structures in terms of interacting superat. shells. As a result, [Sn@Cu12@Sn20]12- can be regarded formally as [{Sn@Cu12}4-@{Sn20}8-], which ensures a favorable electronic configuration with a sizable HOMO-LUMO gap for the inner core [Sn@Cu12]4-. The interaction between the [Sn@Cu12]4- and [Sn20]8- layers involves a concentric bonding interaction of s-, p- and d-type. The approach employed here is suggested and demonstrated to be a useful strategy for rationalizing multilayer endohedral clusters, which can be extended to nanoparticles or even to less sym. systems.
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861Damianos, K.; Solokha, P.; Ferrando, R. Core–shell and matryoshka structures in MgNi nanoalloys: A computational study. RSC Adv. 2013, 3, 9419– 9430, DOI: 10.1039/c3ra40861bGoogle Scholar861https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXot1eitL8%253D&md5=8a7fdc75d56a43b2138dec79c46ad701Core-shell and matryoshka structures in MgNi nanoalloys: a computational studyDamianos, Konstantina; Solokha, Pavlo; Ferrando, RiccardoRSC Advances (2013), 3 (24), 9419-9430CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The structures of MgNi nanoparticles are searched for by a computational methodol. combining atomistic modeling, global optimization searches and d.-functional theory (DFT) calcns. Sizes of up to 45 atoms are considered for several different compns. Core-shell structures are found in most cases. However, there are also exceptions, such as the three-shell high-symmetry matryoshka clusters Mgi12g32 (of anti-Mackay icosahedral geometry) and Mgi12g14 (of tetrahexahedral geometry). Other high-symmetry structures comprise the core-shell cubic Mg8Ni6, the tetrahexahedral cluster Mg14Ni13 and the pentadocahedral cluster Mg21Ni12. The results of the atomistic models are compared with DFT calcns., obtaining a good agreement.
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862Borbon-Gonzalez, D. J.; Fortunelli, A.; Barcaro, G.; Sementa, L.; Johnston, R. L.; Posada-Amarillas, A. Global minimum Pt13M20 (M = Ag, Au, Cu, Pd) dodecahedral core–shell clusters. J. Phys. Chem. A 2013, 117, 14261– 14266, DOI: 10.1021/jp410079tGoogle Scholar862https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvV2ku7%252FM&md5=ea9320bfbde7fab7cd71ae545a5292a4Global Minimum Pt13M20 (M = Ag, Au, Cu, Pd) Dodecahedral Core-Shell ClustersBorbon-Gonzalez, Dora J.; Fortunelli, Alessandro; Barcaro, Giovanni; Sementa, Luca; Johnston, Roy L.; Posada-Amarillas, AlvaroJournal of Physical Chemistry A (2013), 117 (51), 14261-14266CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We report finding dodecahedral core-shell structures as the putative global min. of Pt13M20 (M = Ag, Au, Cu, Pd) clusters by using the basin hopping method and the many-body Gupta model potential to model interat. interactions. These nanoparticles consist of an icosahedral 13-atom platinum core encapsulated by a 20 metal-atom shell exhibiting a dodecahedral geometry (and Ih symmetry). The interaction between the icosahedral platinum core and the dodecahedral shell is analyzed in terms of the increase in vol. of the icosahedral core, and the strength and stickiness of M-Pt and M-M interactions. Low-lying metastable isomers are also obtained. Local relaxations at the DFT level are performed to verify the energetic ordering and stability of the structures predicted by the Gupta potential finding that dodecahedral core-shell structures are indeed the putative global min. for Pt13Ag20 and Pt13Pd20, whereas decahedral structures are obtained as the min. energy configurations for Pt13Au20 and Pt13Cu20 clusters.
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863Wang, J. L.; Bai, J. L.; Jellinek, J.; Zeng, X. C. Gold-coated transition-metal anion [Mn13@Au20]- with ultrahigh magnetic moment. J. Am. Chem. Soc. 2007, 129, 4110– 4111, DOI: 10.1021/ja0664234Google Scholar863https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXivF2jsbo%253D&md5=98146ef6a0510e484f5aafa72aa89583Gold-Coated Transition-Metal Anion [Mn13@Au20]- with Ultrahigh Magnetic MomentWang, Jinlan; Bai, Jaeil; Jellinek, Julius; Zeng, Xiao ChengJournal of the American Chemical Society (2007), 129 (14), 4110-4111CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors presented results of DFT computations which show that coating magnetic clusters with gold can both enhance (as in the case of [Mn13@Au20]-) and attenuate (as in the case of [Co13@Au20]-) the net magnetic moment of the clusters. The degree of magnetic enhancement for (Mn13@Au20)- (44 μB) as well as the cluster's bistability at both low (2 μB) and high (44 μB) spin states suggests that the gold coated manganese clusters may be good prototype systems for nanomagnetism applications.
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864Bai, X.; Lv, J.; Wu, H.-S. A giant enhancement of magnetic moment in a ternary three-shell icosahedral cluster: Fe@Mn12@Au20. Mol. Phys. 2020, 118, 1– 7, DOI: 10.1080/00268976.2019.1659434Google ScholarThere is no corresponding record for this reference.
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865Kou, C. Y.; Zhuang, L.; Wang, G. Q.; Cui, H.; Yuan, H. K.; Tian, C. L.; Wang, J. Z.; Chen, H. [TM13@Bi20]- clusters in three-shell icosahedral matryoshka structure: Being as superatoms. RSC Adv. 2015, 5, 92134– 92143, DOI: 10.1039/C5RA19194GGoogle Scholar865https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12ksb%252FF&md5=901fdab710803bed6dde00685573156c[TM13@Bi20]- clusters in three-shell icosahedral matryoshka structure: being as superatomsKou, C. Y.; Zhuang, L.; Wang, G. Q.; Cui, H.; Yuan, H. K.; Tian, C. L.; Wang, J. Z.; Chen, H.RSC Advances (2015), 5 (112), 92134-92143CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Using the d. functional theory (DFT) method, the 33-atom intermetalloid [TM13@Bi20]- clusters (TM = 3d, 4d), which are composed of Bi20 pentagonal dodecahedra surrounding TM12 icosahedra with a single TM atom at the center, have been systematically examd. to explore the possibility of clusters being as superatoms. The results show that most TM13 clusters can be attractively encapsulated into Bi20 cage to form a stable core-shell configuration, exhibiting an interesting progression of thermal stability along the 3d and 4d periods. Taking into account the structural stability (binding energy, embedding energy, and core-shell interaction) as well as the chem. stability (HOMO-LUMO gap), we proposed that [TM13@Bi20]- clusters with Ti and Mn doping in 3d series (Zr and Ag doping in 4d series) are specially stable and to be the protyle superatoms. For such systems, the MO shapes and energy alignments are in analogy with the at. patterns, coinciding the general characters of superat. orbitals. The closed core superat. shell together with the partially-filled valence superat. shell configuration leads to magnetic moment in stable [TM13@Bi20]-, e.g., [Mn13@Bi20]- cluster with the half-filled subshell can be assigned as a magnetic superatom owning to its modest HOMO-LUMO gap of 0.37 eV and large magnetic moment of 36 μB. The exchange-splitting in TM-3d states is found to be the driving force for the improvement of exchange-splitting of superat. states.
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866Sigmon, G. E.; Ling, J.; Unruh, D. K.; Moore-Shay, L.; Ward, M.; Weaver, B.; Burns, P. C. Uranyl–peroxide interactions favor nanocluster self-assembly. J. Am. Chem. Soc. 2009, 131, 16648– 16649, DOI: 10.1021/ja907837uGoogle Scholar866https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtleksb7K&md5=bfb58acf39d85f61972354d7bc351f62Uranyl-Peroxide Interactions Favor Nanocluster Self-AssemblySigmon, Ginger E.; Ling, Jie; Unruh, Daniel K.; Moore-Shay, Laura; Ward, Matthew; Weaver, Brittany; Burns, Peter C.Journal of the American Chemical Society (2009), 131 (46), 16648-16649CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)[(UO2)20(O2)30]20-, a cluster contg. 20 uranyl pentagonal triperoxides, was isolated in the compd. Na11(N(C3H7)4)9[(UO2)20(O2)30]·9H2O and characterized assuming the smallest possible fullerene topol. consisting only of 12 pentagons. It is the only fullerene isomer with 20 vertices. Oxalate was used to crystallize fragments of larger uranyl peroxide clusters, and these fragments and other known structures indicate that the U-O2-U dihedral angle is inherently bent. Such bending probably is essential in directing the self-assembly of uranyl peroxide polyhedra into closed clusters.
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867Hu, H. S.; Kaltsoyannis, N. High spin ground states in Matryoshka actinide nanoclusters: A computational study. Chem. - Eur. J. 2018, 24, 347– 350, DOI: 10.1002/chem.201705196Google Scholar867https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFegu7nL&md5=5bf32dedf4148fa8bb09de849dcc2ef6High Spin Ground States in Matryoshka Actinide Nanoclusters: A Computational StudyHu, Han-Shi; Kaltsoyannis, NikolasChemistry - A European Journal (2018), 24 (2), 347-350CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Inspired by the exptl. synthesized Na12@[(UO2)(O2)1.5]208- ("Na12@U20") cluster, we have explored computationally the substitution of the Na cations by many other metals. 6 other M12@U20 systems are found to be stable (M=K+, Rb+, Cs+, Ag+, Mg2+, Fe2+). For 3 of these (Mg2+, Ag+ and Na+), the cluster can support a group 16 dianion at its center, forming a new type of Matryoshka ("Russian Doll") actinide nanocluster E@M12@U20 (E=S2-, Se2-, Te2-, and Po2-). These systems have 3-shell, onion-like geometries with nearly perfect Ih symmetry. Seeking to create clusters with very high spin ground states, we have replaced M by Mn2+ and U20 by Np20 and Pu20, generating clusters with max. possible S values of 80/2 and 100/2 resp. Only in the presence of a central S2-, however, are these electronic configurations the most stable; the novel Matryoshka Pu nanocluster S@Mn12@Pu20 is predicted to have the highest ground state spin yet reported for a mol. cluster.
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868Zhao, J.; Wang, X.; Zhao, J.; Luo, R.; Shen, X.; Zhu, D.; Jing, S. [Ln4@Ln4] matryoshka tetrahedron: A novel secondary building unit. CrystEngComm 2016, 18, 863– 867, DOI: 10.1039/C5CE02417JGoogle Scholar868https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitV2msbjL&md5=334b8e6311b63a7e6b234c0f010ce131[Ln4@Ln4] matryoshka tetrahedron: a novel secondary building unitZhao, Jie; Wang, Xin; Zhao, Jing; Luo, Rui; Shen, Xuan; Zhu, Dunru; Jing, SuCrystEngComm (2016), 18 (6), 863-867CODEN: CRECF4; ISSN:1466-8033. (Royal Society of Chemistry)A novel secondary building unit, a Russian nesting doll [Ln4@Ln4] tetrahedron, was developed for building metal-org. frameworks, [Ln2(μ3-OH)L2.5(H2O)2]·0.5DMF (Ln = Eu, Gd, Dy, H2L = 2,2'-dimethoxy-4,4'-biphenyldicarboxylic acid), with an unprecedented binodal (3,20)-connected 3-dimensional network by using a linear bridge-linking ligand. The photoluminescence of the Eu MOF and magnetic properties of the Gd and Dy MOFs were studied.
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869Iwasa, T.; Nakajima, A. Geometric, electronic, and optical properties of monomer and assembly of endohedral aluminum superatomic clusters. J. Phys. Chem. C 2013, 117, 21551– 21557, DOI: 10.1021/jp406054kGoogle Scholar869https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsFGrs7bK&md5=7611f2682dd66b689b59c0acb475636fGeometric, Electronic, and Optical Properties of Monomer and Assembly of Endohedral Aluminum Superatomic ClustersIwasa, Takeshi; Nakajima, AtsushiJournal of Physical Chemistry C (2013), 117 (41), 21551-21557CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)D. functional computations are used to evaluate the geometric, electronic, and optical properties of endohedral Al clusters X@Al12 (X = B, Al, Si, P) and their assemblies. All X@Al12+/0/- clusters are perfect or slightly distorted icosahedral structures, with the exception of Al13+, which is highly distorted. The projected d. of states (PDOS) onto the spherical harmonics of monomers clearly reveals superatom behavior and electron shell closings of F orbitals in a 40-electron species. The electronic absorption spectrum of SiAl12 is analyzed in terms of the superatom orbitals. The optimized structures of X@Al12-Y@Al12 (X-Y = Si-Si, B-P, Al-P) dimers are constructed by facing the sides of the monomers in a staggered fashion. The PDOS of the dimers mostly exhibit 5 hybridizations: S, P, SD, PF, and SDG. The exceptions are HOMO, which possesses a DFG hybridized character and lies between the PF and SDG regions, and LUMO, which possesses a DG hybridized character. By analyzing the simulated absorption spectra of the B@Al12-P@Al12 and Al13-P@Al12 heterodimers, charge transfers from B/Al@Al12 to P@Al12 are found in the visible region, weakly accompanying the opposite charge transfer. 7. The heterodimers have substantial charge carriers, estd. as the difference in electron counts from the closed-shell Si@Al12, with slight charge depletions (∼0.2). The charge distributions in B@Al12 and P@Al12 are essentially unaltered by the insertion of Si@Al12 into the heterodimer, resulting in that the heterotrimer possesses a larger dipole moment than the heterodimer.
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870Sun, Q.; Wang, Q.; Briere, T.; Kawazoe, Y. Dimer interactions of magic W@Si12 clusters. J. Phys.: Condens. Matter 2002, 14, 4503– 4508, DOI: 10.1088/0953-8984/14/17/320Google Scholar870https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktFSnsbY%253D&md5=8d79efe2aa3a2a8ffeb4217014fb5a43Dimer interactions of magic W@Si12 clustersSun, Q.; Wang, Q.; Briere, T. M.; Kawazoe, Y.Journal of Physics: Condensed Matter (2002), 14 (17), 4503-4508CODEN: JCOMEL; ISSN:0953-8984. (Institute of Physics Publishing)The authors explored the possibility of constructing a Si nanotube by using the metal-stabilized and tube-shaped Si cluster W@Si12 as a basic unit and present detailed B3LYP-DFT calcns. of the interactions. of the dimers. The interactions are orientation dependent, and no interactions exist if the stacking is along the sixfold axis. The W atom can be used as a spacer to link the two units, resulting in a metastable structure. Due to the large surface stress in such a small one-dimensional system, sixfold stacking cannot be extended, and thus the trimer is not dynamically stable. Further, the most stable geometry for the dimer is seriously distorted. Consequently, it is difficult to construct a Si nanotube using this W@Si12 tube-shaped unit.
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871Robles, R.; Khanna, S. N. Magnetism in assembled and supported silicon endohedral cages: First-principles electronic structure calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 80, 115414, DOI: 10.1103/PhysRevB.80.115414Google Scholar871https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1agtrnK&md5=5480f6edddb22b4ea045f3bf2b176d9aMagnetism in assembled and supported silicon endohedral cages: First-principles electronic structure calculationsRobles, R.; Khanna, S. N.Physical Review B: Condensed Matter and Materials Physics (2009), 80 (11), 115414/1-115414/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)First principles electronic structure calcns. on a free CrSi12 cluster, a (CrSi12)2 dimer, and CrSi12 clusters supported on Si(111) surfaces have been carried out within a gradient cor. d. functional formalism using a supercell approach. The ground state of CrSi12 is a Cr centered hexagonal biprism of Si atoms in which the Cr spin moment is completely quenched. As two CrSi12 motifs are brought together, they form different composite units depending on initial direction of approach and, in most cases, the composite cluster is found to have a net spin moment. Cluster assemblies obtained by depositing CrSi12 motifs on a Si(111) surface exhibit similar finite spin moments for several initial directions of approach. An anal. of the electronic states shows that the origin of the magnetic moment lies in those Cr d-states that do not mix with silicon sp states. The studies suggest the possibility of forming silicon-based magnetic semiconductors through such assemblies.
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872Torres, M.; Fernández, E.; Balbás, L. Study of the structural and electronic properties of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n (n ≤ 9) aggregates from first principles. J. Phys. Chem. C 2011, 115, 335– 350, DOI: 10.1021/jp1066742Google Scholar872https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhs1SrsbrE&md5=0db995484866055a98c9064dec1d56a6Study of the Structural and Electronic Properties of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n (n ≤ 9) Aggregates from First PrinciplesTorres, M. B.; Fernandez, E. M.; Balbas, L. C.Journal of Physical Chemistry C (2011), 115 (2), 335-350CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Recent exptl. and theor. work has established that the ground state and low-lying energy isomers of endohedral M@Si16 clusters (M = Sc-, Ti, or V+) have a nearly spherical cagelike form, an at.-like closed shell electronic structure, and a large HOMO-LUMO gap of ∼2 eV, which suggests the use of these clusters as basic units (superatoms) in the assembly of optoelectronic materials. As a first step in that direction, in this work are studied, by means of first-principles DFT-PBE calcns., the trends in the formation of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n aggregates as their sizes increase (n ≤ 9). We identify esp. stable linear, planar, and three-dimensional patterns that can be used to grow low-dimensional periodical systems. When n ≥ 2, the aggregates with greater binding energy result from the bonding of n supermol. units having D4d symmetry for the M@Si16 cage, instead of the Frank-Kasper symmetry ground state of the basic superatom. Particularly interesting aggregates are (i) [Ti@Si16]n rings when n ≥ 6, which can be grown as wires or nanotubes; (ii) rings and linear forms of [Sc@Si16K]n aggregates having a rich variety of nearly degenerate isomers differing in the bonding site of K atoms and strongly varying elec. dipole moments; and (iii) [M@Si16X]3m wires (m = 1-3) formed by vertically stacking the [M@Si16X]3 starlike trimer with rotation of 60° between consecutive trimer units, which show interesting magnetic configurations for M = V and X = F. The HOMO-LUMO gap for the most favorable structure decreases with size, and the aggregates become nearly metallic when n ≤ 9.
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873Iwasa, T.; Nakajima, A. Geometric, electronic, and optical properties of a superatomic heterodimer and trimer: Sc@Si16–V@Si16 and Sc@Si16–Ti@Si16–V@Si16. J. Phys. Chem. C 2012, 116, 14071– 14077, DOI: 10.1021/jp302752gGoogle Scholar873https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XovFaqs7c%253D&md5=b5b9ded829bd55de94d0e8bc8730a6edGeometric, Electronic, and Optical Properties of a Superatomic Heterodimer and Trimer: Sc@Si16-V@Si16 and Sc@Si16-Ti@Si16-V@Si16Iwasa, Takeshi; Nakajima, AtsushiJournal of Physical Chemistry C (2012), 116 (26), 14071-14077CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The geometric, electronic, and optical properties of a heterodimer and trimer consisting of metal-encapsulating silicon cage clusters, M@Si16 (M = Sc, Ti, V) with D4d symmetry, were studied using the DFT-CAM-B3LYP method to explore the possibility of using these clusters as building blocks for a nanometer scale heteroassembly. Among the possible low-lying geometries, the linear-form of the hetero-oligomers was adopted as a model system, where the D4d monomers are covalently bonded by facing their squares in an eclipsed fashion. The heterodimer consisting of halogen-like Sc@Si16 and alk.-like V@Si16 has a dipole moment of 7.63 D, and its occupied and virtual frontier orbitals are localized to V@Si16 and to Sc@Si16, resp. Some of the inner MOs exhibit superat. bonding and antibonding character. The electronic excitations involve charge-transfer states mainly from V@Si16 to Sc@Si16 in the optical energy region. The linear heterotrimer of Sc@Si16-Ti@Si16-V@Si16, formed by inserting the rare-gas-like Ti@Si16, has a larger dipole moment of 15.6 D and one or more localized frontier orbitals compared to the dimer. We propose possible formation routes to realize the present hetero-oligomers using photoexcitation or energy-selective electron injection into several LUMOs of the monomers that are suitable for linear-oligomerization.
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874Liu, J.; Guo, P.; Zheng, J.; Zhao, P.; Jiang, Z.; Shen, L. Self-assembly of a two-dimensional sheet with Ta@Si16 superatoms and its magnetic and photocatalytic properties. J. Phys. Chem. C 2020, 124, 6861– 6870, DOI: 10.1021/acs.jpcc.9b10196Google Scholar874https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXnslyjuw%253D%253D&md5=89662a72be024c0ecce38a2deb8274d8Self-Assembly of a Two-Dimensional Sheet with Ta@Si16 Superatoms and Its Magnetic and Photocatalytic PropertiesLiu, Jia; Guo, Ping; Zheng, Jiming; Zhao, Puju; Jiang, Zhenyi; Shen, LeiJournal of Physical Chemistry C (2020), 124 (12), 6861-6870CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The development of new functional materials with a rational design, controllable assembly, and tunable property is highly demanded. Here, we take the exptl. synthesized Ta@Si16 superatom as a building block to design several low-lying Ta@Si16 dimers and self-assembled two-dimensional (2D) sheets, and then study their structural stability and magnetic and photocatalytic properties as well as potential applications by d. functional theory and mol. dynamics. Our results show that the Ta@Si16 superatom can maintain its cage frame of geometric structure in all of these self-assembled structures at room temp. It is found that the honeycomb hexagonal lattice Hex-d structure, the line-contact and the face-contact Ta@Si16/C60 interfacial structures are three new semiconductors with band gaps of 0.89, 0.43, and 1.32 eV, resp. As an intrinsic ferromagnet, the line-contact Ta@Si16/C60 structure has a Curie temp. of 294 K. Furthermore, our study shows that the face-contact Ta@Si16/C60 one might be a good photocatalyst.
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875Park, S.; Kim, G.; Kwon, Y.-K. First-principles investigation on dimerization of metal-encapsulated gold nanoclusters. RSC Adv. 2014, 4, 192– 198, DOI: 10.1039/C3RA45742GGoogle Scholar875https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVeisrjF&md5=bba730142fde70ab5be4f775e6ae728aFirst-principles investigation on dimerization of metal-encapsulated gold nanoclustersPark, Sora; Kim, Gunn; Kwon, Young-KyunRSC Advances (2014), 4 (1), 192-198CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)D. functional theory is used to study dimerization of metal-encapsulated gold nanoclusters M@Au12 (M = W, Mo) with Ih or Oh symmetry, and their structural and electronic properties. To det. the most stable dimer structure in each case, various configurations are considered. We find that during dimerization, gold atoms near the interface tend to form inter-cluster triangular bonds, which stabilize two monomer clusters by about 3.3-3.5 eV. The dimerization along a specific axis selected as the z axis causes the symmetry redn. of each M@Au12 cluster resulting in the modification of electronic structures. It is found that all the stable dimers exhibit a much smaller HOMO-LUMO gap than those of their comprising monomers. Such a gap decrease is mainly attributed to the dz2 orbital splitting of the central atoms owing to dimerization. We also calc. the vibrational modes and the corresponding IR-active spectra, which are distinguishable for different dimer configurations. In addn., we find that the IR-active modes of the Oh-based dimer structures appear to be red-shifted in comparison to those of Ih-based ones. Thus, the IR spectra may be utilized exptl. to discriminate dimer configurations with different central metal atoms and/or dissimilar structural symmetries.
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876Kumar, V. Predictions of novel nanostructures of silicon by metal encapsulation. Comput. Mater. Sci. 2004, 30, 260– 268, DOI: 10.1016/j.commatsci.2004.03.012Google Scholar876https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXlvVeitro%253D&md5=84eda250127f3caf9b47b4ae218e127bPredictions of novel nanostructures of silicon by metal encapsulationKumar, VijayComputational Materials Science (2004), 30 (3-4), 260-268CODEN: CMMSEM; ISSN:0927-0256. (Elsevier Science B.V.)Recent studies using ab initio total energy calcns. have shown exciting possibilities of developing novel metal encapsulated caged clusters of silicon with fullerene-like, Frank-Kasper and other polyhedral structures. In contrast to carbon for which empty cage fullerene structures are stable with 20 or more atoms, 10-16 atom silicon cage structures are stabilized by a guest metal atom. These nanoclusters are predicted to exhibit luminescence in the visible range and could find applications in biol. systems, optoelectronics, and as tagging material. The Raman and IR spectra have been calcd. and they could help in the exptl. identification of the structures. Interaction of these clusters with metal as well as oxygen or hydrogen atoms show that the fullerene structure is stable. Also the interaction between clusters themselves is weak and the ionization potentials, large. These properties make them attractive for cluster assembled materials such as nanowires, nanotubes, and other 2 and 3D structures. Studies on hydrogen interaction have led to the predictions of empty center hydrogenated silicon fullerenes SinHn with large HOMO-LUMO gaps. These could further be doped endohedrally or exohedrally to produce novel silicon fullerenes with a variety of properties opening new ways of using silicon for diverse applications.
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877Kumar, V. Recent theoretical progress on electronic and structural properties of clusters: Permanent electric dipoles, magnetism, novel caged structures, and their assemblies. Comput. Mater. Sci. 2006, 35, 375– 381, DOI: 10.1016/j.commatsci.2004.10.012Google Scholar877https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1OitrjI&md5=914a64c6e52f5a485756c7af6faa92d0Recent theoretical progress on electronic and structural properties of clusters: Permanent electric dipoles, magnetism, novel caged structures, and their assembliesKumar, VijayComputational Materials Science (2006), 35 (3), 375-381CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)A review. We present a brief account of the recent progress in the theor. understanding of the electronic and structural properties of clusters of metals and semiconductors from ab initio calcns. The origin of the recently obsd. permanent elec. dipoles in Nb clusters, the occurrence of magnetism in clusters of non-magnetic elements such as Pd, Rh, and Ru, as well as the findings of the metal encapsulated clusters of Si, Ge, Sn, and Pb are discussed. Empty caged clusters of Si, Ge, and Sn have also been shown to be stable with H capping. These can be functionalized by exohedral doping for different applications while endohedral doping of the cages can be used to tailor highest occupied-LUMO gaps as well as the magnetic properties. Assemblies of such clusters could lead to novel nanostructures and new phases of these materials.
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878Reber, A. C.; Khanna, S. N.; Castleman, A. W. Superatom compounds, clusters, and assemblies: Ultra alkali motifs and architectures. J. Am. Chem. Soc. 2007, 129, 10189– 10194, DOI: 10.1021/ja071647nGoogle Scholar878https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXotFGnsb0%253D&md5=6d75258cf5c0b8bdd42c9cd97adca8e8Superatom Compounds, Clusters, and Assemblies: Ultra Alkali Motifs and ArchitecturesReber, Arthur C.; Khanna, Shiv N.; Castleman, A. Welford, Jr.Journal of the American Chemical Society (2007), 129 (33), 10189-10194CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)It has recently been demonstrated that chosen clusters of specific size and compn. can exhibit behaviors reminiscent of atoms in the periodic table and hence can be regarded as superatoms forming a third dimension. An Al13 cluster has been shown to mimic the behavior of halogen atoms. Here, we demonstrate that superatom compds. formed by combining superhalogens (Al13) with superalkalis (K3O and Na3O) can exhibit novel chem. and tunable electronic features. For example, Al13(K3O)3 is shown to have low first and second ionization potentials of 2.49 and 4.64 eV, resp., which are lower than alkali atoms and can be regarded as ultra alkali motifs. Al13K3O is shown to be a strongly bound mol. that can be assembled into stable superatom assemblies (Al13K3O)n with Al13 and K3O as the superatom building blocks. The studies illustrate the potential of creating new materials with an unprecedented control on phys. and electronic properties.
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879Reveles, J.; Baruah, T.; Zope, R. R. Al12Cu Superatom as stable building block of ionic salts. J. Phys. Chem. C 2015, 119, 5129– 5137, DOI: 10.1021/jp512261vGoogle Scholar879https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVeqs7o%253D&md5=f607957646410b4e9fd5112af46a561fAl12Cu Superatom as Stable Building Block of Ionic SaltsReveles, J. U.; Baruah, Tunna; Zope, Rajendra R.Journal of Physical Chemistry C (2015), 119 (9), 5129-5137CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The neutral copper aluminum cluster complex Al12CuM3 [M = K, K3O, and K(2,2,2-crypt)] has been investigated at the PBE96 level of theory. It is found that Al12Cu could be considered a superatom mimic of a phosphorus atom. It shows large electron affinity and is able to receive three electrons from elements or compds. with low ionization energies like K, K3O, or K(2,2,2-crypt) to become a stable electronic closed shell with a large gap between the highest occupied and lowest unoccupied MOs (HOMO-LUMO gap). Theor. calcns. confirm that similar to the phosphorus atom in PK3, the superatom Al12Cu cluster could form ionic salts, as shown from stable dimers, trimers, and tetramers of the Al12Cu{K(2,2,2-crypt)}3 complex. On the basis of the maintenance of its integrity in these assemblies it could be predicted that Al12CuM3 holds great potential as a building block for the development of future nanostructured materials. Furthermore, the choice of the K(2,2,2-crypt) mols. to stabilize the salt opens a route to exptl. generate cluster base ionic salts, and we expect that our work motivates exptl. investigations of these assemblies.
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880Okada, N.; Uchida, N.; Kanayama, T. Thermal stability of amorphous Si-rich W silicide films composed of W-atom-encapsulated Si clusters. J. Appl. Phys. 2017, 121, 225308, DOI: 10.1063/1.4985248Google Scholar880https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVWjtr3I&md5=6078b79b97cc77a6e3ab6734ce082ae7Thermal stability of amorphous Si-rich W silicide films composed of W-atom-encapsulated Si clustersOkada, Naoya; Uchida, Noriyuki; Kanayama, ToshihikoJournal of Applied Physics (Melville, NY, United States) (2017), 121 (22), 225308/1-225308/5CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)The excellent thermal stability of an amorphous film composed of W atom-encapsulated Si (WSin) clusters with n ≥8, formed by thermal deposition using WF6 and SiH4 gases, was demonstrated. To det. how the structure of the constituting clusters affected film thermal stability, films contg. un-encapsulated WSin clusters where the W atom was not fully encapsulated in the Sin cage, with n ≤7, were prepd. Annealing effect was examd. by Raman scattering and optical absorption measurements with repeated 10-min isochronal annealing in a N2 atmosphere at 500-1100°. Films composed of WSin clusters completely encapsulating W atoms with a uniform compn. of n = 12 remained in the same amorphous structure up to 1000°, although partial crystn. of Si began at 1100°. Stability decreased when the film contained un-encapsulated WSin clusters, even with an av. film compn. of n ≤10; partial crystn. of Si and WSi2 was obsd. after annealing at 800°. D. functional theory calcns. indicated a structure assembled from three encapsulated WSi12 clusters preserves the bonding topol. of the constituting clusters where Si atoms are strongly bonded, and accounted for the high thermal stability of the film composed of encapsulated WSin clusters. (c) 2017 American Institute of Physics.
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881Torres, M.; Fernández, E.; Balbás, L. Theoretical study of the structural and electronic properties of aggregates, wires, and bulk phases formed from M@Si16 superatoms (M = Sc–, Ti, V+). Int. J. Quantum Chem. 2011, 111, 444– 462, DOI: 10.1002/qua.22750Google Scholar881https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVGkt7zP&md5=06006e48323f62805ea9855bb1e4a5f3Theoretical study of the structural and electronic properties of aggregates, wires, and bulk phases formed from M = Si16 superatoms (M = Sc-, Ti, V+)Torres, M. B.; Fernandez, E. M.; Balbas, L. C.International Journal of Quantum Chemistry (2011), 111 (2), 444-462CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)Starting with the nearly spherical endohedral M@Si16 cage-like clusters (M = Sc-, Ti, V+) in their fullerene-like isomerical form with D4d symmetry, we study the trends in the formation of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n aggregates as their size increase (n ≤ 9). We identify specially stable linear, planar, and three-dimensional patterns, which can serve to grow low-dimensional infinite systems. The structure and cohesive energy of a few infinite chains of that type are optimized. We also present calcns. of fcc, bcc, and single cubic crystal meta stable phases having the Ti@Si16 superatom as basic unit, as well as cubic NaCl and CsCl bulk structures of Sc@Si16K and V@Si16F supermols. The orientation and isomerization of the superatom or supermol. in the cubic cell plays an important role. The projected d. of states of V@Si16F crystal with NaCl structure shows a meta stable ferromagnetic phase due to polarization of d electrons of vanadium. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011.
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882Singh, A. K.; Kumar, V.; Briere, T. M.; Kawazoe, Y. Cluster assembled metal encapsulated thin nanotubes of silicon. Nano Lett. 2002, 2, 1243– 1248, DOI: 10.1021/nl025789lGoogle Scholar882https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvFWnsb8%253D&md5=359b6860f413860e5431730df67f1d15Cluster Assembled Metal Encapsulated Thin Nanotubes of SiliconSingh, Abhishek Kumar; Kumar, Vijay; Briere, Tina M.; Kawazoe, YoshiyukiNano Letters (2002), 2 (11), 1243-1248CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Using ab initio total energy calcns. the recently found metal encapsulated silicon clusters Si12Be can be assembled to form hexagonal nanotubes of silicon. This is in contrast to undoped silicon structures that are distorted and have a tendency to agglomerate. The finite nanotubes have varying HOMO-LUMO gaps depending upon the length and amt. of doping. However, infinite nanotubes are metallic, sym., and stable, making metal encapsulation a useful route to generate metallic silicon nanowires for miniature devices.
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883Menon, M.; Andriotis, A. N.; Froudakis, G. Structure and stability of Ni-encapsulated Si nanotube. Nano Lett. 2002, 2, 301– 304, DOI: 10.1021/nl015695wGoogle Scholar883https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XhtVKhtLc%253D&md5=795ffdca385f907d9ecfd0e9f9a7d3d0Structure and Stability of Ni-Encapsulated Si NanotubeMenon, Madhu; Andriotis, Antonis N.; Froudakis, GeorgeNano Letters (2002), 2 (4), 301-304CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Using tight-binding mol. dynamics and ab initio methods, we predict the existence of a novel quasi-one-dimensional Ni-Si form in which a Si nanotube is stabilized by an encapsulation of the Ni chain. The resulting structure is found to be metallic with finite DOS at the Fermi level. Our work follows the recent exptl. work showing that endohedral encapsulation of transition metal atoms stabilizes the Si polyhedral cage.
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884Andriotis, A. N.; Mpourmpakis, G.; Froudakis, G. E.; Menon, M. Stabilization of Si-based cage clusters and nanotubes by encapsulation of transition metal atoms. New J. Phys. 2002, 4, 78, DOI: 10.1088/1367-2630/4/1/378Google ScholarThere is no corresponding record for this reference.
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885Mpourmpakis, G.; Froudakis, G. E.; Andriotis, A. N.; Menon, M. Understanding the structure of metal encapsulated Si cages and nanotubes: Role of symmetry and d-band filling. J. Chem. Phys. 2003, 119, 7498– 7502, DOI: 10.1063/1.1607309Google Scholar885https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXns1Gntbk%253D&md5=7c3e475b69cf35ce0078fdf0ef72424aUnderstanding the structure of metal encapsulated Si cages and nanotubes: Role of symmetry and d-band fillingMpourmpakis, Giannis; Froudakis, George E.; Andriotis, Antonis N.; Menon, MadhuJournal of Chemical Physics (2003), 119 (14), 7498-7502CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Using the B3LYP-DFT method we studied the stability of Si-based cages and nanotubes stabilized by encapsulated transition metal atoms (TMAs). The stabilization of these cages and nanotubes as well as their magnetic properties are strongly dependent on a delicate interplay between the attainable symmetry of the system and the d-band filling of the encapsulated TMA. As a result, encapsulated TMAs of the early 3-d series lead to tubular structures of C6 symmetry and antiferromagnetic alignment between the magnetic moment of the TMA and that of the Si atoms. On the other hand, the encapsulated late 3-d elements lead to tubules of the C5 symmetry and to a ferromagnetic alignment of the metal and Si magnetic moments. Encapsulated Fe atoms (being near the middle of the 3-d series) lead to tubular structures of either C6 or C5 symmetry.
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886Tan Pham, H.; Minh Tam, N.; Van Duong, L.; Phuong Pham-Ho, M.; Tho Nguyen, M. Mn2@Si15: The smallest triple ring tubular silicon cluster. Phys. Chem. Chem. Phys. 2015, 17, 17566– 17570, DOI: 10.1039/C5CP02257FGoogle ScholarThere is no corresponding record for this reference.
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887Wei-xiao, J.; Chenglin, L. Density-functional investigation of hexagonal prism transition-metal-encapsulated cage M2Si18 (M = Sc–Zn) clusters. Modell. Simul. Mater. Sci. Eng. 2010, 18, 025011, DOI: 10.1088/0965-0393/18/2/025011Google ScholarThere is no corresponding record for this reference.
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888Ji, W.; Luo, C. Structures, magnetic properties, and electronic counting rule of metals-encapsulated cage-like M2Si18 (M = Ti-Zn) clusters. Int. J. Quantum Chem. 2012, 112, 2525– 2531, DOI: 10.1002/qua.23245Google Scholar888https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtl2gsLvM&md5=cfa8d3dbdc080d40946ced9880f1b0f4Structures, magnetic properties, and electronic counting rule of metals-encapsulated cage-like M2 Si18 (M = Ti-Zn) clustersJi, Weixiao; Luo, ChenglinInternational Journal of Quantum Chemistry (2012), 112 (12), 2525-2531CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)The geometries, magnetic properties and stabilities of the transition metal (TM) atoms encapsulated M2Si18 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) clusters have been systematically calcd. by using the d. function theory with generalized gradient approxn. Only when the doping metal atom has no more than half-full d electronic shell, a double hexagonal prism cage-like M2Si18 structure could form. The total moments of M2Si18 are either 0 or 2μB. Co2Si18 is the most stable cluster among all 3d doped M2Si18 clusters. The model of shell closure at the TM atom may be helpful to understand the stability of M2Si18 clusters. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011.
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889Nayak, S.; Gruner, M.; Entel, P. Possible one-dimensional structures obtained from transition metal atom doped silicon nanoclusters. Phase Transitions 2006, 79, 709– 716, DOI: 10.1080/01411590601030217Google Scholar889https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXpt1CnsA%253D%253D&md5=94ae19a6c079aa3a83f202afb49f6423Possible one-dimensional structures obtained from transition metal atom doped silicon nanoclustersNayak, S. K.; Gruner, M. E.; Entel, P.Phase Transitions (2006), 79 (9-10), 709-716CODEN: PHTRDP; ISSN:0141-1594. (Taylor & Francis Ltd.)Silicon clusters doped with transition metal (TM) atoms show profound stability and prefer endohedral encapsulation of TM atoms. The early 3d elements (M) adopt the D6h symmetry for Si12M, while the late 3d elements acquire the D5h symmetry for Si10M clusters. The central 3d element stabilizes both types of clusters. The silicon atoms attain an induced magnetic moment from the TM atom which gives rise to a broad spectrum of magnetic behavior in these clusters depending on M. Suitable stacking of clusters along the direction perpendicular to their plane of symmetry is a possible route to grow one-dimensional structures like nanorods and nanowires. Calcns. with the DFT-GGA method are performed to study the above aspect for transition metal atom doped silicon clusters.
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890Wang, J.; Zhao, J.; Ma, L.; Wang, G.; King, R. B. Stability and magnetic properties of Fe encapsulating in silicon nanotubes. Nanotechnology 2007, 18, 235705, DOI: 10.1088/0957-4484/18/23/235705Google Scholar890https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXosVehtrk%253D&md5=560956f7754662cea56cb54e6bdb153cStability and magnetic properties of Fe encapsulating in silicon nanotubesWang, Jianguang; Zhao, Jijun; Ma, Li; Wang, Guanghou; King, R. BruceNanotechnology (2007), 18 (23), 235705/1-235705/8CODEN: NNOTER; ISSN:0957-4484. (Institute of Physics Publishing)Using all-electron d. functional theory with gradient correction, we have investigated the stability of quasi-one-dimensional tubular nanostructures by stacking the pentagonal FeSi10 prism and hexagonal FeSi12 prism along their axes. The local magnetic moments on Fe atoms in finite hexagonal nanotubes increase linearly with tube length, whereas the magnetism in most finite pentagonal nanotubes are quenched owing to the charge transfer and strong hybridization between 4s and 3d states of Fe and 3s and 3p states of Si. The infinite hexagonal nanotube with stoichiometry of FeSi6 is found to be ferromagnetic with magnetic moment per Fe atom comparable to the bulk value. Both pentagonal and hexagonal nanotubes exhibit metallic behavior in the case of finite and infinite structures. These theor. results provide useful information for application of spintronics and other nanodevices.
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891Gueorguiev, G. K.; Stafström, S.; Hultman, L. Nano-wire formation by self-assembly of silicon–metal cage-like molecules. Chem. Phys. Lett. 2008, 458, 170– 174, DOI: 10.1016/j.cplett.2008.04.108Google Scholar891https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmsFChsbc%253D&md5=be565c4eb1e6be6763357521f748e441Nanowire formation by self-assembly of silicon-metal cage-like moleculesGueorguiev, G. K.; Stafstroem, S.; Hultman, L.Chemical Physics Letters (2008), 458 (1-3), 170-174CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)By using DFT calcns. we show that nanowires consisting of endohedral MSi12 cage-like mols. are stable esp. for light transition metal elements (M = Fe, Ni, Co, Ti, V, and Cu). The nanowire assemblies are stabilized by the metal atoms located along their principal axes and can be seen as close Si-based analogs of C nanotubes, but with hexagonal cross-section due to the D6h-symmetry of their MSi12 building blocks. Independently on M, with the increase in the length of a (MSi12)m nanowire, its HOMO-LUMO gap decreases gradually. The metallic behavior of (MSi12)m defines them as possible conductive components for self-assembled nanodevices.
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892Peng, Q.; Shen, J.; Chen, N.-X. Geometry and electronic stability of tungsten encapsulated silicon nanotubes. J. Chem. Phys. 2008, 129, 034704, DOI: 10.1063/1.2949548Google Scholar892https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptVOhsLk%253D&md5=eb19113fbcf136ce27eb7a9a1a03b30dGeometry and electronic stability of tungsten encapsulated silicon nanotubesPeng, Qi; Shen, Jiang; Chen, Nan-XianJournal of Chemical Physics (2008), 129 (3), 034704/1-034704/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)D. functional theory involving generalized gradient approxn. (both PW91 and BLYP level calcns. are considered and compared) correlation functional is used to investigate the stability of W encapsulated Wn@Si6n+6 (n = 1-6) hexagonal prism (HP) nanotubes and Wn@Si8n+4 (n = 1-6) AB2 type nanotubes. We found that the stability of HP type metal encapsulated silicon nanotubes (MESNTs) exhibits odd-even (O-E) oscillation behavior vs. the cluster size which has been proven by the O-E oscillation pattern of the formation energy and the embedded energy. The strong interaction between W and W atoms made W3@Si24 HP type nanotube unstable and we explained why Hiura et al. did not observe clusters bigger than W2@Si18 in their expt. After that, we proposed a new kind of AB2 type MESNT in which the strong interaction between W and W atoms has been eliminated effectively, and it might be connected to form longer nanowire structures. Big distortions appeared for both type structures after reoptimized at BLYP level (the initial structures were chosen as those optimized at PW91 level theory) calcn. Metallic character of these two types of MESNTs has been identified and AB2-MESNTs were found to be more stable than HP type MESNTs by comparing their linearly fitted total binding energy at BLYP level theory. (c) 2008 American Institute of Physics.
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893Singh, A. K.; Kumar, V.; Kawazoe, Y. Metal encapsulated nanotubes of silicon and germanium. J. Mater. Chem. 2004, 14, 555– 563, DOI: 10.1039/b311850aGoogle Scholar893https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtlWmsbo%253D&md5=d783386d4c65ce3961e15d4869df5d61Metal encapsulated nanotubes of silicon and germaniumSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiJournal of Materials Chemistry (2004), 14 (4), 555-563CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)A review. Nanoforms of silicon such as nanoparticles and nanowires were attracting much attention and recent findings of novel metal encapsulated silicon clusters as well as nanotubes have opened up new avenues for the development of silicon nanostructures. The authors review these recent developments and discuss the findings of the metal encapsulated nanotubes of silicon and germanium using ab initio total energy calcns. These nanotubes are generally found to be metallic. The metalicity is not induced by the doping of metal atoms, though they stabilize silicon and germanium in tubular forms. Transition metal atoms such as Mn and Fe lead to nanotubes that are ferromagnetic making them interesting as nanomagnets. Antiferromagnetic and ferrimagnetic phases also were obtained. A novel aspect of these magnetic nanotubes is the possibility of developing half-metallic nanotubes that could be interesting for nano-spintronics applications. Further possibilities of semiconducting silicon nanotubes are discussed.
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894Singh, A. K.; Briere, T. M.; Kumar, V.; Kawazoe, Y. Magnetism in transition-metal-doped silicon nanotubes. Phys. Rev. Lett. 2003, 91, 146802, DOI: 10.1103/PhysRevLett.91.146802Google Scholar894https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnvVKmur0%253D&md5=1384f099036e5dc952f87e67af910ca1Magnetism in Transition-Metal-Doped Silicon NanotubesSingh, Abhishek Kumar; Briere, Tina M.; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2003), 91 (14), 146802/1-146802/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Using first-principles d. functional calcns., we show that hexagonal metallic silicon nanotubes can be stabilized by doping with 3d transition metal atoms. Finite nanotubes doped with Fe and Mn have high local magnetic moments, whereas Co-doped nanotubes have low values and Ni-doped nanotubes are mostly nonmagnetic. The infinite Si24Fe4 nanotube is found to be ferromagnetic with nearly the same local magnetic moment on each Fe atom as in bulk iron. Mn-doped nanotubes are antiferromagnetic, but a ferromagnetic state lies only 0.03 eV higher in energy with a gap in the majority spin bands near the Fermi energy. These materials are interesting for silicon-based spintronic devices and other nanoscale magnetic applications.
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895Dhaka, K.; Bandyopadhyay, D. Magnetism, structures and stabilities of cluster assembled TM@Si nanotubes (TM = Cr, Mn and Fe): A density functional study. Dalton Trans. 2016, 45, 12432– 12443, DOI: 10.1039/C6DT01252CGoogle Scholar895https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFShsLzE&md5=386b63b5c76468390b24e11d6d387520Magnetism, structures and stabilities of cluster assembled TM@Si nanotubes (TM = Cr, Mn and Fe): a density functional studyDhaka, Kapil; Bandyopadhyay, DebashisDalton Transactions (2016), 45 (31), 12432-12443CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)The present study reports transition metal (TM = Cr, Mn and Fe) doped silicon nanotubes with tunable band structures and magnetic properties by careful selection of cluster assemblies as building blocks using the 1st-principles d. functional theory. The transition metal doping and in addn., the hydrogen termination process can stabilize the pure silicon nanoclusters or cluster assemblies and then it could be extended as magnetic nanotubes with finite magnetic moments. Study of the band structures and d. of states (DOS) of different empty and TM doped nanotubes (Type 1 to Type 4) show that these nanotubes are useful as metals, semiconductors, semi-metals and half-metals. These designer magnetic materials could be useful in spintronics and magnetic devices of nanoscale order.
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896Li, J.; Wang, J.; Zhao, H.-Y.; Liu, Y. Magnetic silicon nanotube: Role of encapsulated europium atoms. J. Phys. Chem. C 2013, 117, 10764– 10769, DOI: 10.1021/jp401090pGoogle Scholar896https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXms1Oqs7s%253D&md5=e2fc4a29ee0cfd74a354c61a89b0ec36Magnetic Silicon Nanotube: Role of Encapsulated Europium AtomsLi, Jing; Wang, Jing; Zhao, Hui-Yan; Liu, YingJournal of Physical Chemistry C (2013), 117 (20), 10764-10769CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A europium-encapsulating silicon nanotube, Eu2@Si30, was predicted based on DFT-PW91 calcns. Electronic structure anal. shows that in Si-Si chem. bonding is characterized by sp2-like hybridization induced by the europium atoms; the hybridizations evidently enhances the stability of the silicon nanotube. The nanotube of Eu2@Si30, with D5h symmetry, retains a high spin magnetic moment of 10 μB. On the basis of Eu2Si30 nanotube, a stable magnetic silicon nanotube (SiNT) was obtained, and it is found to be metallic. Similar to the predictions and speculation of Daedalus, the new magnetic SiNT may have potential applications in the fields of spintronics and high-d. magnetic storage.
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897Wang, J.; Liu, Y. Magnetic silicon fullerenes: Experimental exploration and theoretical insight. J. Cluster Sci. 2016, 27, 861– 873, DOI: 10.1007/s10876-015-0959-6Google Scholar897https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFanur%252FE&md5=259fa72ec4aea7ee5f4132502dade8abMagnetic Silicon Fullerenes: Experimental Exploration and Theoretical InsightWang, Jing; Liu, YingJournal of Cluster Science (2016), 27 (3), 861-873CODEN: JCSCEB; ISSN:1040-7278. (Springer)The present article summarizes progress in research on silicon clusters with encapsulated metal atoms, and specifically focuses on the recent identification of magnetic silicon fullerenes. Considering that C20 forms the smallest known fullerene, the Si20 cluster is of particular interest in this context. While the pure hollow Si20 cage is unstable due to the lack of sp2 hybridization, endohedral doping with a range of metal atoms has been considered to be an effective way to stabilize the cage structure. In order to seek out suitable embedded atoms for stabilizing Si20, a broad search has been made across elements with relatively large at. radius. The rare earth elements have been found to be able to stabilize the Si20 cage in the neutral state by forming R@Si20 fullerene cages. Among these atoms, Eu@Si20 has been reported to yield a stable magnetic silicon fullerene. The central europium atom has a large magnetic moment of nearly 7.0 μB. In addn., based on a stable Eu2Si30 tube, a magnetic silicon nanotube has been constructed and discussed. These magnetic silicon fullerenes and nanotubes may have potential applications in the fields of spintronics and high-d. magnetic storage.
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898Sirichantaropass, S.; García-Suárez, V.; Lambert, C. J. Electronic properties of alkali-and alkaline-earth-intercalated silicon nanowires. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 075328, DOI: 10.1103/PhysRevB.75.075328Google Scholar898https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXislarsb0%253D&md5=aa511f53f72c1f2ab194623875606a50Electronic properties of alkali- and alkaline-earth-intercalated silicon nanowiresSirichantaropass, S.; Garcia-Suarez, V. M.; Lambert, C. J.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (7), 075328/1-075328/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We present a first-principles study of the electronic properties of silicon clathrate nanowires intercalated with various types of alkali- or alk.-earth atoms. We find that the band structure of the nanowires can be tailored by varying the impurity atom within the nanowire. The electronic character of the resulting systems can vary from metallic to semiconducting with direct band gaps. These properties make the nanowires specially suitable for elec. and optoelectronic applications.
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899Singh, A. K.; Kumar, V.; Kawazoe, Y. Surface physics, low-dimensional systems, and related topics-Ferromagnetism and piezomagnetic behavior in Mn-doped germanium nanotubes. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 69, 233406, DOI: 10.1103/PhysRevB.69.233406Google Scholar899https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXls1Wjtr4%253D&md5=9dae3822728dee2e331e910100024be0Ferromagnetism and piezomagnetic behavior in Mn-doped germanium nanotubesSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 69 (23), 233406/1-233406/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Using ab initio d. functional calcns., pentagonal and hexagonal nanotubes of Ge can be stabilized in the antiprism structure by doping with Mn atoms. In both cases the infinite nanotubes are metallic and ferromagnetic. Hexagonal nanotubes have the highest av. magnetic moments of 3.06 μB per Mn atom found so far in metal doped nanotubes of semiconductors, while the pentagonal nanotubes show a transition from a ferromagnetic to a ferrimagnetic state upon compression with an abrupt change in the magnetic moments, leading to the possibility of these nanotubes to act as a nano-piezomagnet.
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900Singh, A. K.; Kumar, V.; Kawazoe, Y. Design of a very thin direct-band-gap semiconductor nanotube of germanium with metal encapsulation. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 075312, DOI: 10.1103/PhysRevB.71.075312Google Scholar900https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXitVKisbc%253D&md5=6c8d8a000a6faae94e4fad5578d7dd09Design of a very thin direct-band-gap semiconductor nanotube of germanium with metal encapsulationSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (7), 075312/1-075312/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using ab initio total energy calcns. we design a very thin semiconducting nanotube of Ge with a direct band gap by encapsulation of Mo or W. This finding is an outcome of studies of assemblies of Ge18Nb2 clusters into nanotubes. The infinite Nb-doped nanotube is metallic. However, the electronic structure has a significant gap above the Fermi level. When Nb is replaced by a Z+1 element such as Mo or W, it leads to the formation of a semiconducting nanotube. The at. structure of these nanotubes is based on a novel alternate prism and antiprism stacking of hexagonal rings of germanium. Such an arrangement is optimal for Ge18M2 (M = Nb, Mo, and W) clusters that serve as the building blocks of nanotubes. By just changing the M atom in the growth process, we can form metallic, semiconducting, and n or p types of nanotubes, opening new possibilities for nanoscale devices.
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901Singh, A. K.; Kumar, V.; Kawazoe, Y. Metal encapsulated nanotubes of germanium with metal dependent electronic properties. Eur. Phys. J. D 2005, 34, 295– 298, DOI: 10.1140/epjd/e2005-00162-1Google Scholar901https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtFOqtrk%253D&md5=7b2079fa21c875a9a04e1ac191489db3Metal encapsulated nanotubes of germanium with metal dependent electronic propertiesSingh, A. Kumar; Kumar, V.; Kawazoe, Y.European Physical Journal D: Atomic, Molecular and Optical Physics (2005), 34 (1-3), 295-298CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)Using ab initio total energy calcns. we demonstrate that the nanotubes of germanium with at. structure based on an alternate prism and antiprism stacking of hexagonal rings, can be stabilized by metal encapsulation. The V or Nb doped infinite nanotube is metallic. However, Mo doping leads to the formation of a metal encapsulated direct band gap semiconducting nanotube of germanium. These nanotubes with metal dependent electronic properties could prove to be vital for the development of future nanotechnologies.
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902Zhou, J.; Giri, S.; Jena, P. 18-Electron rule inspired Zintl-like ions composed of all transition metals. Phys. Chem. Chem. Phys. 2014, 16, 20241– 20247, DOI: 10.1039/C4CP03141EGoogle Scholar902https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlCjt73J&md5=96d6c3ee0d0b19a091877c3e9196637318-Electron rule inspired Zintl-like ions composed of all transition metalsZhou, Jian; Giri, Santanab; Jena, PurusottamPhysical Chemistry Chemical Physics (2014), 16 (37), 20241-20247CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Zintl phase compds. constitute a unique class of compds. composed of metal cations and covalently bonded multiply charged cluster anions. Potential applications of these materials in soln. chem. and thermoelec. materials have given rise to renewed interest in the search for new Zintl ions. Up to now these ions have been mostly composed of group 13, 14, and 15 post-transition metal elements and no Zintl ions composed of all transition metal elements are known. Using gradient cor. d. functional theory we show that the 18-electron rule can be applied to design a new class of Zintl-like ions composed of all transition metal atoms. We demonstrate this possibility by using Ti@Au122- and Ni@Au62- di-anions as examples of Zintl-like ions. Predictive capability of our approach is demonstrated by showing that FeH64- in an already synthesized complex metal hydride, Mg2FeH6, is a Zintl-like ion, satisfying the 18-electron rule. We also show that novel Zintl phase compds. can be formed by using all transition metal Zintl-like ions as building blocks. For example, a two-dimensional periodic structure of Na2[Ti@Au12] is semiconducting and nonmagnetic while a one-dimensional periodic structure of Mg[Ti@Au12] is metallic and ferromagnetic. Our results open the door to the design and synthesis of a new class of Zintl-like ions and compds. with potential for applications.
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903Yong, Y.; Cui, H.; Zhou, Q.; Su, X.; Kuang, Y.; Li, X. Ultrathin nanowire based on icosahedral W@Au12 and application as NO gas sensor. J. Phys. Chem. Solids 2019, 127, 68– 75, DOI: 10.1016/j.jpcs.2018.12.008Google Scholar903https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisFaqtr3O&md5=7d60615475e023c70723a9eb65214e62Ultrathin nanowire based on icosahedral W@Au12 and application as NO gas sensorYong, Yongliang; Cui, Hongling; Zhou, Qingxiao; Su, Xiangying; Kuang, Yanmin; Li, XiaohongJournal of Physics and Chemistry of Solids (2019), 127 (), 68-75CODEN: JPCSAW; ISSN:0022-3697. (Elsevier Ltd.)In this study, we used first-principles calcns. to investigate the structural and electronic properties of an ultrathin nanowire formed by assembling icosahedral W@Au12 clusters and its application as a NO gas sensor. An ultrathin nanowire with a diam. of about 5.52 Å was produced via the coalescence of icosahedral W@Au12 clusters. The W@Au12-based nanowire exhibited semiconducting properties with a direct band gap. Frequency anal. and mol. dynamics simulations indicated that the nanowire was particularly stable at T = 300 K. The nanowire chemisorbed a NO mol. with moderate adsorption energy, and the N atom in NO bonding with the Au atom was the most stable bond. Anal. of the Boltzmann distribution and transition state demonstrated that the most stable configuration was particularly likely to form. The electronic properties of the W@Au12-based nanowire were changed dramatically by NO adsorption, with a transition from semiconducting to conducting behavior after NO adsorption. However, the adsorption of CO2, CH4, O2, H2, N2, or H2O mols. had little effect on the conductance of the nanowire. Our results indicated that the W@Au12-based nanowire sensor was highly sensitive and selective. The recovery time for the nanowire-based NO sensor was about 12 s at T = 300 K. Therefore, due to its moderate adsorption energy, significant change in the elec. cond., and very rapid recovery time, we conclude that the W@Au12-based nanowire is a promising gas sensor with high performance at NO detection.
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904Li, X.; Yang, J. Computational design of one-dimensional ferromagnetic semiconductors in transition metal embedded stannaspherene nanowires. Chin. J. Chem. 2019, 37, 1021– 1024, DOI: 10.1002/cjoc.201900166Google Scholar904https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1GjtbbE&md5=da46274a25f619671c42073d94395c63Computational Design of One-Dimensional Ferromagnetic Semiconductors in Transition Metal Embedded Stannaspherene NanowiresLi, Xingxing; Yang, JinlongChinese Journal of Chemistry (2019), 37 (10), 1021-1024CODEN: CJOCEV; ISSN:1001-604X. (Wiley-VCH Verlag GmbH & Co. KGaA)Developing low dimensional semiconductors with moderate band gaps, intrinsic ferromagnetism and large magnetic anisotropy energies (MAEs) is very desirable for high-speed nano-spintronic devices, which, however, still remains a big challenge. Here, via first principles calcns., a potential route to realize such materials is proposed based on a new class of one-dimensional transition metal (TM) embedded stannaspherene (Sn122-) nanowires [TM2(Sn12)]∞ (TM = Ti-Ni). Three semiconductors with robust ferromagnetism are achieved with TM = V, Cr and Fe, which all exhibit direct or quasi-direct band gaps around 1.0 eV, rendering their great potentials for visible light optoelectronic applications. Interestingly, [Cr2(Sn12)]∞ and [Fe2(Sn12)]∞ are both identified as bipolar magnetic semiconductors (BMS) with valence and conduction band edges spin polarized in the opposite directions, which are promising for realizing switch of carriers spin orientation by elec. gating, while [V2(Sn12)]∞ exhibits a half semiconductor (HSC) property with valence and conduction band edges spin polarized in the same direction and can be used for spin-polarized carriers generation. Moreover, sizable MAEs are discovered in these nanowires, which are at least two orders of magnitude larger than those of Fe, Co and Ni bulks and also significantly larger than current ferromagnetic semiconductors.
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905Rudberg, E.; Sałek, P.; Luo, Y. Nonlocal exchange interaction removes half-metallicity in graphene nanoribbons. Nano Lett. 2007, 7, 2211– 2213, DOI: 10.1021/nl070593cGoogle Scholar905https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntVWkt7Y%253D&md5=9e407fca4f9315208fb74e0e3c74f328Nonlocal Exchange Interaction Removes Half-Metallicity in Graphene NanoribbonsRudberg, Elias; Salek, Pawel; Luo, YiNano Letters (2007), 7 (8), 2211-2213CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Band gap studies of zigzag-edge graphene ribbons are presented. While earlier calcns. at LDA level show that zigzag-edge graphene ribbons become half-metallic when cross-ribbon elec. fields are applied, our calcns. with hybrid d. functional demonstrate that finite graphene ribbons behave as half-semiconductors. The spin-dependent band gap can be changed in a wide range, making possible many applications in spintronics.
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906Saranin, A. A.; Zotov, A. V.; Kotlyar, V. G.; Kasyanova, T. V.; Utas, O. A.; Okado, H.; Katayama, M.; Oura, K. Ordered arrays of Be-encapsulated Si nanotubes on Si (111) surface. Nano Lett. 2004, 4, 1469– 1473, DOI: 10.1021/nl049195pGoogle Scholar906https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXlvFGitLo%253D&md5=a737dd5f77e7c5d3f149b814cf17529bOrdered Arrays of Be-Encapsulated Si Nanotubes on Si(111) SurfaceSaranin, Alexander A.; Zotov, Andrey V.; Kotlyar, Vasily G.; Kasyanova, Tatiana V.; Utas, Oleg A.; Okado, Hideaki; Katayama, Mitsuhiro; Oura, KenjiroNano Letters (2004), 4 (8), 1469-1473CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Using submonolayer Be deposition onto the Si(111) 7 × 7 surface under ultrahigh vacuum conditions, highly ordered honeycomb-like nanostructure arrays have been obtained. Scanning tunneling microscopy anal. of the nanostructure building blocks has revealed that they have compn., size, and properties similar to those theor. predicted for the short Be-encapsulated Si nanotubes.
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907Stegmaier, S.; Fässler, T. F. Na2. 8Cu5Sn5. 6: A crystalline alloy featuring intermetalloid ∞1{Sn0.6@Cu5@Sn5} double-walled nanorods with pseudo-five-fold symmetry. Angew. Chem. 2012, 124, 2701– 2704, DOI: 10.1002/ange.201107985Google ScholarThere is no corresponding record for this reference.
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908Wang, Y.; Saranin, A.; Zotov, A.; Lai, M.; Chang, H. Random and ordered arrays of surface magic clusters. Int. Rev. Phys. Chem. 2008, 27, 317– 360, DOI: 10.1080/01442350801943708Google Scholar908https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXkt12hsL0%253D&md5=7d28b2d5246371b9d49c82fafb00e0bfRandom and ordered arrays of surface magic clustersWang, Y. L.; Saranin, A. A.; Zotov, A. V.; Lai, M. Y.; Chang, H. H.International Reviews in Physical Chemistry (2008), 27 (2), 317-360CODEN: IRPCDL; ISSN:0144-235X. (Taylor & Francis Ltd.)A review. Surface magic clusters (SMCs) are clusters exhibiting enhanced stability at certain sizes on a particular surface. Through the formation of SMCs, it is possible to grow an ensemble of nanostructures on a surface with extremely small or essentially zero size dispersion. Such an ensemble of nanostructures with identical size and at. structure is highly desirable for certain nanotechnologies that rely on the homogeneity in the phys. and chem. properties of the constituent nanostructures. This review summarizes current exptl. observations and understanding of SMCs and discusses the most recent progress in the formation of a two-dimensional lattice of SMCs, whose constituent clusters have not only identical size and structure but also the same local environment due to the translational symmetry of the system.
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909Li, J.-L.; Jia, J.-F.; Liang, X.-J.; Liu, X.; Wang, J.-Z.; Xue, Q.-K.; Li, Z.-Q.; John, S. T.; Zhang, Z.; Zhang, S. Spontaneous assembly of perfectly ordered identical-size nanocluster arrays. Phys. Rev. Lett. 2002, 88, 066101, DOI: 10.1103/PhysRevLett.88.066101Google Scholar909https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xptl2jsw%253D%253D&md5=3b053404a523a51f8c4c0d8c79f7b9f6Spontaneous Assembly of Perfectly Ordered Identical-Size Nanocluster ArraysLi, Jian-Long; Jia, Jin-Feng; Liang, Xue-Jin; Liu, Xi; Wang, Jun-Zhong; Xue, Qi-Kun; Li, Zhi-Qiang; Tse, John S.; Zhang, Zhenyu; Zhang, S. B.Physical Review Letters (2002), 88 (6), 066101/1-066101/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)A method, by which periodic two-dimensional arrays of identical metal clusters of nanometer size and spacing could be spontaneously obtained by taking advantage of surface mediated clustering, is reported. The versatility of the method is demonstrated for a broad range of metals on Si(111)-( 7×7) substrates. In situ scanning tunneling microscopy anal. of In clusters, combined with first-principles total energy calcns., unveils unique initial-stage at. structures of the surface-supported clusters and the vital steps that lead to the success of this method. A strong interaction between the clusters and the surface holds the key to the obsd. cluster sizes.
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910Zhong, X.; Lee, K.; Choi, B.; Meggiolaro, D.; Liu, F.; Nuckolls, C.; Pasupathy, A.; De Angelis, F.; Batail, P.; Roy, X. Superatomic two-dimensional semiconductor. Nano Lett. 2018, 18, 1483– 1488, DOI: 10.1021/acs.nanolett.7b05278Google Scholar910https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhs1yku7c%253D&md5=a93a9b2f4ceb339f74641af92291f513Superatomic two-dimensional semiconductorZhong, Xinjue; Lee, Kihong; Choi, Bonnie; Meggiolaro, Daniele; Liu, Fang; Nuckolls, Colin; Pasupathy, Abhay; De Angelis, Filippo; Batail, Patrick; Roy, Xavier; Zhu, XiaoyangNano Letters (2018), 18 (2), 1483-1488CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Structural complexity is of fundamental interest in materials science because it often results in unique phys. properties and functions. Founded on this idea, the field of solid state chem. has a long history and continues to be highly active, with new compds. discovered daily. By contrast, the area of two-dimensional (2D) materials is young, but its expansion, although rapid, is limited by a severe lack of structural diversity and complexity. Here, we report a novel 2D semiconductor with a hierarchical structure composed of covalently linked Re6Se8 clusters. The material, a 2D structural analog of the Chevrel phase, is prepd. via mech. exfoliation of the van der Waals solid Re6Se8Cl2. Using scanning tunneling spectroscopy, photoluminescence and UPS, and first-principles calcns., we det. the electronic bandgap (1.58 eV), optical bandgap (indirect, 1.48 eV), and exciton binding energy (100 meV) of the material. The latter is consistent with the partially 2D nature of the exciton. Re6Se8Cl2 is the first member of a new family of 2D semiconductors whose structure is built from superat. building blocks instead of simply atoms; such structures will expand the conceptual design space for 2D materials research.
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911Miyazaki, T.; Kanayama, T. Ultrathin layered semiconductor: Si-rich transition metal silicide. Jpn. J. Appl. Phys. 2007, 46, L28– L30, DOI: 10.1143/JJAP.46.L28Google Scholar911https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXht1GgsLY%253D&md5=a5762cabd79bc499e4c0ddc5614a2e96Ultrathin layered semiconductor. Si-rich transition metal silicideMiyazaki, Takehide; Kanayama, ToshihikoJapanese Journal of Applied Physics, Part 2: Letters & Express Letters (2007), 46 (1-3), L28-L30CODEN: JAPLD8 ISSN:. (Japan Society of Applied Physics)By ab initio calcn., we predict an atomically thin, stable layered semiconducting crystal (ZrSi12)n, which may be a prototype candidate material for the thin film channels of ultimately scaled metal-oxide-semiconductor (MOS) transistors. This material is composed of 3 at. layers, in which a layer of Zr atoms is sandwiched by 2 layers of Si atoms. The Si atoms are arranged in graphene-like structures. This material is favorably formed from isolated ZrSi12 clusters. The energy band gap is of the indirect transition type and ∼0.3 eV in a generalized gradient approxn. to the d. functional theory. Both valence-band max. and conduction-band min. wavefunctions can be characterized by a hybrid of Zr d- and Si p-orbitals.
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912Liu, Z.; Wang, X.; Cai, J.; Zhu, H. Room-temperature ordered spin structures in cluster-assembled single V@Si12 sheets. J. Phys. Chem. C 2015, 119, 1517– 1523, DOI: 10.1021/jp508509eGoogle Scholar912https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFOgtr7K&md5=bfac71b498741a8f9343638781e3d0e9Room-Temperature Ordered Spin Structures in Cluster-Assembled Single V@Si12 SheetsLiu, Zhifeng; Wang, Xinqiang; Cai, Jiangtao; Zhu, HengjiangJournal of Physical Chemistry C (2015), 119 (3), 1517-1523CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Since most of the existing pristine two-dimensional (2D) materials are either intrinsically nonmagnetic or magnetic with small magnetic moment per unit cell and weak strength of magnetic coupling, introducing transition metal atoms in various nanosheets was widely used for achieving a desired 2-dimensional magnetic material. However, the problem of surface clustering for the doped transition metal atoms is still challenging. The authors demonstrate via 1st-principles calcns. that the recently exptl. characterized endohedral Si cage V@Si12 clusters can construct two types of single cluster sheets exhibiting hexagonal porous or honeycomb-like framework with regularly and sep. distributed V atoms. For the ground state of these two sheets, the preferred magnetic coupling is ferromagnetic due to a free-electron-mediated mechanism. By using external strain, the magnetic moments and strength of magnetic coupling for these two sheets can be deliberately tuned, which would be propitious to their advanced applications. More attractively, the authors' 1st-principles mol. dynamics simulations show that both the structure and strength of ferromagnetic coupling for the pristine porous sheet are stable enough to survive at room temp. The insights obtained in this work highlight a new avenue to achieve 2-dimensional Si-based spintronics nanomaterials.
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913Nie, Z.; Guo, P.; Zheng, J.; Zhao, P.; Wan, Y.; Jiang, Z. Electronic and magnetic properties of two dimensional cluster-assembled materials based on TM@Si12 (TM = 3d transition metal) clusters. Comput. Mater. Sci. 2018, 146, 134– 142, DOI: 10.1016/j.commatsci.2018.01.018Google Scholar913https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsF2gtLk%253D&md5=ed06c15cf2441b61c90b63987e6dc549Electronic and magnetic properties of two dimensional cluster-assembled materials based on TM@Si12 (TM = 3d transition metal) clustersNie, Zheng; Guo, Ping; Zheng, Jiming; Zhao, Puju; Wan, Yun; Jiang, ZhenyiComputational Materials Science (2018), 146 (), 134-142CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)Electronic and magnetic properties of two dimensional (2D) cluster-assembled materials based on TM@Si12 (TM = 3d transition metal) clusters were systematically investigated by using the d. functional method. Taking the hexagonal prism TM @Si12 as a building block, we constructed four different kinds of 2D crystal structures, each with a higher stability than the corresponding individual clusters. The hexagonal honeycomb and porous structures are proved to be thermodynamically stable at room temp. by first-principles mol. dynamics simulations, and the honeycomb structure is more favorable in energy than the porous structure. The magnetic coupling properties of the honeycomb and porous structures based on TM@Si12 were further studied in detail. The results show that almost all of the hexagonal TM@Si12 2D lattice exhibit a certain degree of magnetic ordering. These studies provide insights into the effective design of 2D spintronic materials.
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914Nakaya, M.; Iwasa, T.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Formation of a superatom monolayer using gas-phase-synthesized Ta@Si16 nanocluster ions. Nanoscale 2014, 6, 14702– 14707, DOI: 10.1039/C4NR04211EGoogle Scholar914https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhslaisrvE&md5=9e29d9327b0b2b610e3b27cbf8293672Formation of a superatom monolayer using gas-phase-synthesized Ta@Si16 nanocluster ionsNakaya, Masato; Iwasa, Takeshi; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiNanoscale (2014), 6 (24), 14702-14707CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The controlled assembly of superat. nanocluster ions synthesized in the gas phase is a key technol. for constructing a novel series of functional nanomaterials. However, it is generally difficult to immobilize them onto a conductive surface while maintaining their original properties owing to undesirable modifications of their geometry and charge state. In this study, it has been shown that this difficulty can be overcome by controlling the donor-acceptor interaction between nanoclusters and surfaces. Cations of Ta-atom-encapsulated Si16 cage nanoclusters (Ta@Si16) behaving as rare-gas-like superatoms are synthesized in the gas phase and deposited on conductive surfaces terminated with acceptor-like C60 and donor-like α-sexithiophene (6T) mols. Scanning tunneling microscopy and spectroscopy have demonstrated that Ta@Si16 cations can be densely immobilized onto C60-terminated surfaces while retaining their cage shape and pos. charge, which is realized by creating binary charge transfer complexes (Ta@Si16+-C60-) on the surfaces. The Ta@Si16 nanoclusters exhibit excellent thermal stability on C60-terminated surfaces similar to those in the gas phase, whereas the nanoclusters destabilize at room temp. on 6T-terminated surfaces owing to the loss of electronic closure via a change in the charge state.
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915Ohta, T.; Shibuta, M.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Charge transfer complexation of Ta-encapsulating Ta@Si16 superatom with C60. J. Phys. Chem. C 2016, 120, 15265– 15271, DOI: 10.1021/acs.jpcc.6b04955Google Scholar915https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFahur7E&md5=2672146545dfb246e45c70a73b02fde1Charge Transfer Complexation of Ta-Encapsulating Ta@Si16 Superatom with C60Ohta, Tsutomu; Shibuta, Masahiro; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiJournal of Physical Chemistry C (2016), 120 (28), 15265-15271CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The tantalum-encapsulating Si16 cage nanocluster superatom (Ta@Si16) has been a promising candidate for a building block of nanocluster-based functional materials. Its chem. states of Ta@Si16 deposited on an electron acceptable C60 fullerene film were evaluated by X-ray and UV photoelectron spectroscopies (XPS and UPS, resp.). XPS results for Si, Ta, and C showed that Ta@Si16 combines with a single C60 mol. to form the superat. charge transfer (CT) complex, (Ta@Si16)+C60-. The high thermal and chem. robustness of the superat. CT complex has been revealed by the XPS and UPS measurements conducted before and after heat treatment and oxygen exposure. Even when heated to 720 K or subjected to ambient oxygen, Ta@Si16 retained its original framework, forming oxides of Ta@Si16 superatom.
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916Nakaya, M.; Iwasa, T.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Heterodimerization via the covalent bonding of Ta@S16 nanoclusters and C60 molecules. J. Phys. Chem. C 2015, 119, 10962– 10968, DOI: 10.1021/jp511157nGoogle Scholar916https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXislSnsLs%253D&md5=1785876e0048069af5dc2e9bfa5a382aHeterodimerization via the Covalent Bonding of Ta@Si16 Nanoclusters and C60 MoleculesNakaya, Masato; Iwasa, Takeshi; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiJournal of Physical Chemistry C (2015), 119 (20), 10962-10968CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Initial products prepd. via the surface immobilization of Ta-atom-encapsulated Si16 cage (Ta@Si16) nanoclusters on solid surfaces terminated with monolayer films of C60 mols. were investigated using scanning tunneling microscopy (STM). The STM results indicated that marked aggregation and desorption of surface-immobilized Ta@Si16 nanoclusters were not induced, even after thermal annealing at ∼500 K, whereas the local vertical and lateral positions of the Ta@Si16 nanoclusters with respect to neighboring adsorption sites in the C60 film were modified. This local positional transition occurred on C60 monolayer films weakly bonded (via van der Waals forces) to substrates such as highly oriented pyrolytic graphite (HOPG) but did not occur on C60 monolayer films covalently bonded to substrates such as Si(111)7 × 7. These results indicated that the heterodimer consisting of a Ta@Si16 nanocluster and a C60 mol., Ta@Si16-C60, was formed as an initial product via covalent bonding, which inhibited wide-range surface migration of the Ta@Si16 nanoclusters but allowed them to locally change their positions via thermally activated precessional motion. In addn., the transition temp. of the local positional shift was found to decrease as the area d. of the surface-immobilized Ta@Si16 nanoclusters increased, indicating that the barrier height of the precessional motion of the Ta@Si16-C60 heterodimer was decreased due to accumulation of the elastic strain energy generated in the C60 films.
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917Seitsonen, A.; Puska, M. J.; Alatalo, M.; Nieminen, R. M.; Milman, V.; Payne, M. Crystals from metallic clusters: A first-principles calculation. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 48, 1981– 1983, DOI: 10.1103/PhysRevB.48.1981Google Scholar917https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXmtFWhsrY%253D&md5=ee8ad4de3185c803b3caafb53ade7931Crystals from metallic clusters: a first-principles calculationSeitsonen, A. P.; Puska, M. J.; Alatalo, M.; Nieminen, R. M.; Milman, V.; Payne, M. C.Physical Review B: Condensed Matter and Materials Physics (1993), 48 (3), 1981-3CODEN: PRBMDO; ISSN:0163-1829.The interactions of the "magic" Al12Si cluster are studied by first-principles electron-structure calcns. It is shown that clusters arranged into the fcc lattice do not conserve their sepd.-cluster icosahedral structure but coalesce to form a close-packed metal.
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918Liu, F.; Mostoller, M.; Kaplan, T.; Khanna, S.; Jena, P. Evidence for a new class of solids. First-principles study of K(Al13). Chem. Phys. Lett. 1996, 248, 213– 217, DOI: 10.1016/0009-2614(95)01339-3Google Scholar918https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XlvVKgsw%253D%253D&md5=75f3a3cdc4e27d9272f8972fb9c339c5Evidence for a new class of solids. First-principles study of K(Al13)Liu, Feng; Mostoller, Mark; Kaplan, Theodore; Khanna, S. N.; Jena, P.Chemical Physics Letters (1996), 248 (3,4), 213-17CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)The stability of the cryst. phase of a cluster-assembled solid K(Al13) was studied using 1st-principles total energy calcns. K(Al13) may form in the CsCl structure with a lattice const. of 6.52 Å. Unlike the gas phase, in which the ground state of the Al13 cluster is icosahedral, the Al13 becomes cuboctahedral in the solid phase due to crystal field effects. The system is metallic and is stable against lattice distortions. The calcns. suggest that a new metastable solid could be made from two immiscible elements through specially designed synthesis processes.
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919Ashman, C.; Khanna, S.; Liu, F.; Jena, P.; Kaplan, T.; Mostoller, M. (BAl12)Cs: A cluster-assembled solid. Phys. Rev. B: Condens. Matter Mater. Phys. 1997, 55, 15868– 15873, DOI: 10.1103/PhysRevB.55.15868Google Scholar919https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXktVWgu7Y%253D&md5=c10783f31069183f67ea6200abc88b47(BAl12)Cs: a cluster-assembled solidAshman, C.; Khanna, S. N.; Liu, Feng; Jena, P.; Kaplan, T.; Mostoller, M.Physical Review B: Condensed Matter (1997), 55 (23), 15868-15873CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)First-principles calcns. on the geometry and stability of AlnBm clusters have been carried out to examine the effect of size, compn., and electronic-shell filling on their relative stability. It is shown that although Al and B are both trivalent, a BAl12 cluster is more stable than an Al13 by 3.4 eV. The enhanced stability is shown to arise due to the relaxation of surface strain in the Al cage when the central Al is replaced by a smaller B atom. Replacement of an addnl. Al by B to produce B2Al11 results in deformation of the icosahedral BAl12 cage and reduces the stability. The possibility of forming crystals using BAl12 and Cs is examd. via total-energy calcns. It is shown that a solid with icosahedral or cuboctahedral BAl12 and Cs and having the CsCl structure is metastable and could be synthesized.
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920Gong, X. Structure and stability of cluster-assembled solid Al12C(Si): A first-principles study. Phys. Rev. B: Condens. Matter Mater. Phys. 1997, 56, 1091– 1094, DOI: 10.1103/PhysRevB.56.1091Google Scholar920https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXkvVWhsb0%253D&md5=3e15d30ce289d22c64bcb53c7bd07b86Structure and stability of cluster-assembled solid Al12C(Si): a first-principles studyGong, X. G.Physical Review B: Condensed Matter (1997), 56 (3), 1091-1094CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We have proposed a possible crystal structure for the cluster-assembled solids Al12C(Si), and their electronic structures and stabilities have been studied in the framework of d.-functional theory and ab-initio mol. dynamics. We find that Al12C(Si) clusters are condensed by van der Waals force, with a very small cohesive energy of ∼1.1 eV. The combined steepest descent on ions shows that upon the formation of solid the relaxation of at. distances in the Al12C(Si) clusters is very small. The stability of the Al12C solid is also confirmed by a dynamic simulation at low temp.
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921Zhu, Z.-z.; Tian, B. Electronic properties of solid (Al12B)Li in the CsCl structure. Solid State Commun. 1998, 108, 891– 894, DOI: 10.1016/S0038-1098(98)00400-1Google ScholarThere is no corresponding record for this reference.
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922Quan, H.-J.; Gong, X.-G. Electronic structure of cluster-assembled Al12C(Si) solid. Chin. Phys. 2000, 9, 656– 660, DOI: 10.1088/1009-1963/9/9/004Google ScholarThere is no corresponding record for this reference.
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923Mondolfo, L. F. Aluminum alloys: structure and properties; Elsevier: Amsterdam, 2013.Google ScholarThere is no corresponding record for this reference.
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924Reis, C.; Martins, J.; Pacheco, J. Stability analysis of a bulk material built from silicon cage clusters: A first-principles approach. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 76, 233406, DOI: 10.1103/PhysRevB.76.233406Google Scholar924https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtVWrtQ%253D%253D&md5=db4dd8f89d1af7dee631068e09b0be61Stability analysis of a bulk material built from silicon cage clusters: A first-principles approachReis, C. L.; Martins, J. L.; Pacheco, J. M.Physical Review B: Condensed Matter and Materials Physics (2007), 76 (23), 233406/1-233406/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We predict a stable bulk material whose constituent units are the exceptionally stable Ti@Si16 clusters. We use first-principles d. functional theory. Our results provide compelling evidence of a stable, wide-band-gap material crystg. in a hcp. structure in which cages bind weakly, similar to fullerite. We further characterize the structural and electronic properties of this material.
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925Reis, C.; Pacheco, J. Bulk materials made of silicon cage clusters doped with Ti, Zr, or Hf. J. Phys.: Condens. Matter 2010, 22, 035501, DOI: 10.1088/0953-8984/22/3/035501Google Scholar925https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkt12hs7o%253D&md5=1c5c17c442092bb1b50375015266d9a9Bulk materials made of silicon cage clusters doped with Ti, Zr, or HfReis, C. L.; Pacheco, J. M.Journal of Physics: Condensed Matter (2010), 22 (3), 035501/1-035501/7CODEN: JCOMEL; ISSN:0953-8984. (Institute of Physics Publishing)We investigate the feasibility of assembling the exceptionally stable isovalent X@Si16 (X = Ti, Zr and Hf) nanoparticles to form new bulk materials using first-principles d. functional theory. Our results predict the formation of stable, wide band-gap materials crystg. in HCP structures in which the cages bind weakly, similar to fullerite. This study suggests new pathways through which endohedral cage clusters may constitute a viable means toward the prodn. of synthetic materials with pre-defined phys. and chem. properties.
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926Gunnarsson, O. Superconductivity in fullerides. Rev. Mod. Phys. 1997, 69, 575– 606, DOI: 10.1103/RevModPhys.69.575Google Scholar926https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXivVaktL0%253D&md5=8bf26b6a4c41944b718964224a9c3778Superconductivity in fulleridesGunnarsson, O.Reviews of Modern Physics (1997), 69 (2), 575-606CODEN: RMPHAT; ISSN:0034-6861. (American Physical Society)Exptl. studies of the superconductive properties of fullerides are briefly reviewed. Theor. calcns. of the electron-phonon coupling, in particular for the intramol. phonons, are discussed extensively. The calcns. are compared with coupling consts. deduced from a no. of different exptl. techniques. It is discussed why A3C60 are not Mott-Hubbard insulators, in spite of the large Coulomb interaction. Ests. of the Coulomb pseudopotential μ*, describing the effect of the Coulomb repulsion on the supercond., as well as possible electronic mechanisms for the supercond., are reviewed. The calcn. of various properties within the Migdal-Eliashberg theory and attempts to go beyond this theory are described.
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927Laurrabaquio, G. L.; Torres, M. B.; Fernández, E. M.; Balbás, L. C. Trends in the formation of aggregates and crystals from M@Si16 clusters: A study from first principle calculations. J. Math. Chem. 2010, 48, 109– 117, DOI: 10.1007/s10910-009-9637-yGoogle Scholar927https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXnt1alt7k%253D&md5=d84769b24744ab9f86d89df40ad85d4bTrends in the formation of aggregates and crystals from M@Si16 clusters: a study from first principle calculationsLaurrabaquio, Guadalupe Lopez; Torres, M. Begona; Fernandez, Eva. M.; Balbas, L. CarlosJournal of Mathematical Chemistry (2010), 48 (1), 109-117CODEN: JMCHEG; ISSN:0259-9791. (Springer)We have shown recently that the ground state and low-lying energy isomers of the endohedral M@Si16 clusters (M = Sc-, Ti, V+) have a nearly spherical cage-like symmetry with a closed shell electronic structure which conforms them as exceptional stable entities. This is manifested, among other properties, by a large Homo-Lumo gap about 2 eV which suggest the possibility of using these clusters as basic units (superatoms) to construct optoelectronic materials. As a first step in that direction, we have studied in this work, by means of first principles calcns., the trends in the formation of [Ti@Si16]n , [Sc@Si16K]n , and [V@Si16F]n aggregates as their size increases, going from linear to planar to three dimensional arrangements. The most favorable configurations for n ≥ 2 are those formed from the fullerene-like D4d isomer of M@Si16, instead of the ground state Frank-Kasper Td structure of the isolated M@Si16 unit, joined by Si-Si bonds between the Si atoms of the square faces. In all cases the Homo-Lumo gap for the most favorable structure decrease with the size n. Trends for the binding energy, dipole moment, and other electronic properties are also discussed. Several crystal structures constructed from these superatom, supermols., and aggregates have been tested and preliminary results are summarily commented.
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928Pacheco, J.; Gueorguiev, G.; Martins, J. L. First-principles study of the possibility of condensed phases of endohedral silicon cage clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 66, 033401, DOI: 10.1103/PhysRevB.66.033401Google Scholar928https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmtVGgurs%253D&md5=21fbf65c29ff8326f07a61c7e476d855First-principles study of the possibility of condensed phases of endohedral silicon cage clustersPacheco, J. M.; Gueorguiev, G. K.; Martins, Jose LuisPhysical Review B: Condensed Matter and Materials Physics (2002), 66 (3), 033401/1-033401/3CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Recently, a new set of clusters in which twelve Si atoms encapsulate one transition metal atom were found to be esp. stable. Making use of MSi12 clusters (M = Nb,W) we carry out a first-principles study of the possibility of synthesizing a cryst. phase using such clusters as elementary building blocks. To this end we carry out an ab initio study of the interaction energy between two MSi12 clusters as a function of their sepn. We also perform an ab initio Langevin quantum mol. dynamics simulation of solid MSi12 at const. temp. and pressure. We find that the interaction energy between Si atoms in neighboring clusters is comparable to that found in bulk Si. In the solid phase, the cage structure of MSi12 disappears during the simulation. The clusters can not conserve their integrity in condensed phases.
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929Uchida, N.; Kintou, H.; Matsushita, Y.; Tada, T.; Kanayama, T. Synthesis of new amorphous semiconductors assembled from transition-metal-encapsulating Si clusters. Appl. Phys. Express 2008, 1, 121502, DOI: 10.1143/APEX.1.121502Google Scholar929https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXns1ejsA%253D%253D&md5=d6ac4871643e0797fcab880538c1f09bSynthesis of new amorphous semiconductors assembled from transition-metal-encapsulating Si clustersUchida, Noriyuki; Kintou, Hiroshi; Matsushita, Yusuke; Tada, Tetsuya; Kanayama, ToshihikoApplied Physics Express (2008), 1 (12), 121502/1-121502/3CODEN: APEPC4; ISSN:1882-0778. (Japan Society of Applied Physics)The authors synthesized amorphous films composed of transition-metal-encapsulating Si clusters (MSin: M = Mo or Nb) by deposition of hydrogenated MSinHx clusters onto SiO2 substrates followed by annealing at 500° for dehydrogenation. The MoSin (n = 7-16) cluster films are semiconductors with an optical gap > 0.6 eV and resistivity > 1 Ω cm. In particular, the MoSi12 cluster film has a large gap of 1.1 eV and resistivity of 120 Ω cm with high hole mobility of 32 cm2/(V s). In these films, Si atoms form amorphous networks similar to those in hydrogenated amorphous Si but the electronic disorder is reduced using MSin clusters as the building blocks.
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930Matxain, J. M.; Piris, M.; Lopez, X.; Ugalde, J. M. Thermally stable solids based on endohedrally doped ZnS clusters. Chem. - Eur. J. 2009, 15, 5138– 5144, DOI: 10.1002/chem.200802472Google Scholar930https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXls12ktro%253D&md5=1a4e0065cdf2e0da124bb1afc47839a1Thermally Stable Solids Based on Endohedrally Doped ZnS ClustersMatxain, Jon M.; Piris, Mario; Lopez, Xabier; Ugalde, Jesus M.Chemistry - A European Journal (2009), 15 (20), 5138-5144CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The existence of inorg., hollow, fullerene-like ZnS clusters was theor. predicted and then recently confirmed exptl. These clusters trap alkali metals and halogens because the ionization energies (IE) of alkali metals are very similar to the electron affinities (EA) of halogens. This opens the possibility of forming mol. solids composed of these fullerene building blocks because the energy released due to the difference between the IE and EA would be very small. Herein the authors have focused on assembling bare Zn12S12 and endohedral X@Zn12S12-Y@Zn12S12 dimers (X = Na, K; Y = Cl, Br) by considering the square-faces-square orientation of every two adjacent clusters, which leads to a fcc. cubic crystal structure in the solid. The structures were fully optimized in all cases, and their thermal stability was confirmed by ab initio thermal mol. dynamics calcns. The optimum lattice parameter of the solids is ∼13.8 Å, which corresponds to distances of ∼2.5 Å between monomers, which is typical of covalent Zn[bond]S bonds. The resulting solids are nanoporous materials similar to B12N12. Due to their nanoporous structure, these zeolite-shaped solids could be used in heterogeneous catalysis and as storage materials and mol. sieves.
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931Jimenez-Izal, E.; Matxain, J. M.; Piris, M.; Ugalde, J. M. Self-assembling endohedrally doped CdS nanoclusters: New porous solid phases of CdS. Phys. Chem. Chem. Phys. 2012, 14, 9676– 9682, DOI: 10.1039/c2cp41273jGoogle Scholar931https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XptVWmurg%253D&md5=b7514c1fbd365c69857cd8e734bae32fSelf-assembling endohedrally doped CdS nanoclusters: new porous solid phases of CdSJimenez-Izal, Elisa; Matxain, Jon M.; Piris, Mario; Ugalde, Jesus M.Physical Chemistry Chemical Physics (2012), 14 (27), 9676-9682CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Hollow CdS nanoclusters were predicted to trap alkali metals and halogen atoms inside their cavity. Furthermore, electron affinities (EA) of endohedrally halogen doped clusters and ionization potentials (IE) of endohedrally alkali doped clusters were predicted to be very similar. This makes them suitable to build cluster-assembled materials, in the same vein as do related ZnO, ZnS and MgO nanoclusters, which yield porous solid materials. With this aim in mind, we have focused on the assembly of bare CdiSi and endohedral K@CdiSi-X@CdiSi (i = 12, 16, X = Cl, Br) clusters in order to obtain solids with tailored semiconducting and structural properties. Since these hollow nanoclusters possess square and hexagonal faces, three different orientations have to be considered, namely, edge-to-edge (E-E), square-to-square (S-S) and hexagon-to-hexagon (H-H). These three orientations lead to distinct zeolite-like nanoporous bulk CdS solid phases denoted as SOD, LTA and FAU. These solids are low-d. cryst. nanoporous materials that might be useful in a wide range of applications ranging from mol. sieves for heterogeneous catalysis to gas storage templates.
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932Jadzinsky, P. D.; Calero, G.; Ackerson, C. J.; Bushnell, D. A.; Kornberg, R. D. Structure of a thiol monolayer-protected gold nanoparticle at 1.1 Å resolution. Science 2007, 318, 430– 433, DOI: 10.1126/science.1148624Google Scholar932https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtFOjtb%252FP&md5=8d0b844dcfdef488f021281f40da3a21Structure of a Thiol Monolayer-Protected Gold Nanoparticle at 1.1 Å ResolutionJadzinsky, Pablo D.; Calero, Guillermo; Ackerson, Christopher J.; Bushnell, David A.; Kornberg, Roger D.Science (Washington, DC, United States) (2007), 318 (5849), 430-433CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Structural information on nanometer-sized gold particles has been limited, due in part to the problem of prepg. homogeneous material. Here we report the crystn. and x-ray structure detn. of a p-mercaptobenzoic acid (p-MBA)-protected gold nanoparticle, which comprises 102 gold atoms and 44 p-MBAs. The central gold atoms are packed in a Marks decahedron, surrounded by addnl. layers of gold atoms in unanticipated geometries. The p-MBAs interact not only with the gold but also with one another, forming a rigid surface layer. The particles are chiral, with the two enantiomers alternating in the crystal lattice. The discrete nature of the particle may be explained by the closing of a 58-electron shell.
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933Joshi, C. P.; Bootharaju, M. S.; Alhilaly, M. J.; Bakr, O. M. [Ag25(SR)18]−: The “golden” silver nanoparticle. J. Am. Chem. Soc. 2015, 137, 11578– 11581, DOI: 10.1021/jacs.5b07088Google Scholar933https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVahs7%252FP&md5=0aedccfa13c28566d6b94432617e35cf[Ag25(SR)18]-: The "Golden" Silver NanoparticleJoshi, Chakra P.; Bootharaju, Megalamane S.; Alhilaly, Mohammad J.; Bakr, Osman M.Journal of the American Chemical Society (2015), 137 (36), 11578-11581CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Ag nanoparticles with an atomically precise mol. formula [Ag25(SR)18]- (-SR: thiolate) are synthesized, and their single-crystal structure is detd. This synthesized nanocluster is the only Ag nanoparticle that has a virtually identical analog in Au, i.e., [Au25(SR)18]-, in terms of no. of metal atoms, ligand count, superatom electronic configuration, and at. arrangement. Also, both [Ag25(SR)18]- and its Au analog share a no. of features in their optical absorption spectra. This unprecedented mol. analog in Ag to mimic Au offers the 1st model nanoparticle platform to study the centuries-old problem of understanding the fundamental differences between Ag and Au in terms of nobility, catalytic activity, and optical property.
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934Aikens, C. M. Electronic and geometric structure, optical properties, and excited state behavior in atomically precise thiolate-stabilized noble metal nanoclusters. Acc. Chem. Res. 2018, 51, 3065– 3073, DOI: 10.1021/acs.accounts.8b00364Google Scholar934https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1Smt7fF&md5=76013309796c7828faa5b685259dd813Electronic and Geometric Structure, Optical Properties, and Excited State Behavior in Atomically Precise Thiolate-Stabilized Noble Metal NanoclustersAikens, Christine M.Accounts of Chemical Research (2018), 51 (12), 3065-3073CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)Ligand-protected noble metal nanoclusters are of interest for their potential applications in areas such as bioimaging, catalysis, photocatalysis, and solar energy harvesting. These nanoclusters can be prepd. with at. precision, which means that their stoichiometries can be ascertained; the properties of these nanoclusters can vary significantly depending on the exact stoichiometry and geometric structure of the system. This leads to important questions such as: What are the general principles that underlie the phys. properties of these nanoclusters. Do these principles hold for all systems. What properties can be tuned by varying the size and compn. of the system. In this Account, the authors describe research that was performed to analyze the electronic structure, linear optical absorption, and excited state dynamics of thiolate-stabilized noble metal nanoclusters. The authors focus primarily on two systems, Au25(SR)18- and Au38(SR)24, as models for understanding the principles underlying the electronic structure, optical properties, luminescence, and transient absorption in these systems. In these nanoclusters, the orbitals near the HOMO-LUMO gap primarily arise from at. 6sp orbitals located on Au atoms in the Au core. The resulting nanocluster orbitals are delocalized throughout the core of these systems. Below the core-based orbitals lies a set of orbitals that are primarily composed of Au 5d and S 3p AOs from atoms located around the exterior Au-thiolate oligomer motifs. This set of orbitals has a higher d. of states than the set arising from the core 6sp orbitals. Optical absorption peaks in the near-IR and visible regions of the absorption spectrum arise from excitations between core orbitals (lowest energy peaks) and excitations from oligomer-based orbitals to core-based orbitals (higher energy peaks). Nanoclusters with different stoichiometries have varying gaps between the core orbitals themselves as well as between the band of oligomer-based orbitals and the band of core orbitals. These gaps can slow down nonradiative electron transfer between excited states that have different character; the excited state electron and hole dynamics depend on these gaps. Nanoclusters with different stoichiometries also exhibit different luminescence properties. Depending on factors that may include the symmetry of the system and the rigidity of the core, the nanocluster can undergo large or small nuclear changes upon photoexcitation, which affects the obsd. Stokes shift in these systems. This dependence on stoichiometry and compn. suggests that the size and the corresponding geometry of the nanocluster is an important variable that can be used to tune the properties of interest. How does doping affect these principles. Replacement of Au atoms with Ag atoms changes the energetics of the sp and d AOs that make up the nanocluster orbitals. Ag atoms have higher energy sp orbitals, and the resulting nanocluster orbitals are shifted in energy as well. This affects the HOMO-LUMO gap, the oscillator strength for transitions, the spacings between the different bands of orbitals, and, as a consequence, the Stokes shift and excited state dynamics of these systems. Probably nanocluster doping is one way to control and tune properties for use in potential applications.
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935Song, Y.; Lambright, K.; Zhou, M.; Kirschbaum, K.; Xiang, J.; Xia, A.; Zhu, M.; Jin, R. Large-scale synthesis, crystal structure, and optical properties of the Ag146Br2(SR)80 nanocluster. ACS Nano 2018, 12, 9318– 9325, DOI: 10.1021/acsnano.8b04233Google Scholar935https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsFagtrrL&md5=9148ac63309fc7f15f983991687e361bLarge-Scale Synthesis, Crystal Structure, and Optical Properties of the Ag146Br2(SR)80 NanoclusterSong, Yongbo; Lambright, Kelly; Zhou, Meng; Kirschbaum, Kristin; Xiang, Ji; Xia, Andong; Zhu, Manzhou; Jin, RongchaoACS Nano (2018), 12 (9), 9318-9325CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Solving the at. structure of large-sized metal nanoclusters is a highly challenging task yet critically important for understanding the properties and developing applications. Herein, we report a stable silver nanocluster-Ag146Br2(SR)80 (where SR = 4-isopropylbenzenethiolate)-with its structure solved by X-ray crystallog. Gram-scale synthesis with high yield has been achieved by a one-pot reaction, which offers opportunities for functionalization and applications. This silver nanocluster possesses a core-shell structure with a Ag51 core surrounded by a shell of Ag95Br2S80. The Ag51 core can be viewed as a distorted decahedron, endowing this nanocluster with quantized electronic transitions. In the surface-protecting layer, five different types of S-Ag coordination modes are obsd., ranging from the linear Ag-S-Ag to S-Ag3 (triangle) and S-Ag4 (square). Furthermore, temp.-dependent optical absorption and ultrafast electron dynamics are conducted to explore the relationship between the properties and structure, demonstrating that the distorted metal core and "flying saucer"-like shape of this nanocluster have significant effects on the electronic behavior. A comparison with multiple sizes of Ag nanoclusters also provides some insights into the evolution from mol. to metallic behavior.
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936Jin, S.; Du, W.; Wang, S.; Kang, X.; Chen, M.; Hu, D.; Chen, S.; Zou, X.; Sun, G.; Zhu, M. Thiol-induced synthesis of phosphine-protected gold nanoclusters with atomic precision and controlling the structure by ligand/metal engineering. Inorg. Chem. 2017, 56, 11151– 11159, DOI: 10.1021/acs.inorgchem.7b01458Google Scholar936https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVamsbrK&md5=5588a05ede0b7e24867fc286d6c28dd3Thiol-Induced Synthesis of Phosphine-Protected Gold Nanoclusters with Atomic Precision and Controlling the Structure by Ligand/Metal EngineeringJin, Shan; Du, Wenjun; Wang, Shuxin; Kang, Xi; Chen, Man; Hu, Daqiao; Chen, Shuang; Zou, Xuejuan; Sun, Guodong; Zhu, ManzhouInorganic Chemistry (2017), 56 (18), 11151-11159CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Efficient synthesis of atomically precise phosphine-capped Au nanocluster (with >10 metal atoms) is important to deeply understand the relation between structure and properties. Herein, the authors successfully use the thiol-induced synthesis method and obtain three atomically precise phosphine-protected Au nanoclusters. Single-crystal x-ray structural anal. reveals that the nanoclusters are [Au13(Dppm)6](BPh4)3, [Au18(Dppm)6Br4](BPh4)2, and [Au20(Dppm)6(CN)6] (Dppm is bis(diphenylphosphino)methane), which are further confirmed by electrospray ionization mass spectrometry, TGA, and XPS. Meanwhile, [Au18(Dppm)6Br4](BPh4)2 could be converted into [Au13(Dppm)6](BPh4)3 and [Au20(Dppm)6(CN)6] by engineering the surface ligands under excess PPh3 or moderate NaBH3CN, resp. Also, according to the different binding ability of Ag with halogen, the authors successfully achieved target metal exchange on [Au18(Dppm)6Br4](BPh4)2 with Ag-SAdm (HS-Adm is 1-adamantane mercaptan) complex and obtained [AgxAu18-x(Dppm)6Br4](BPh4)2 (x = 1, 2) alloy nanoclusters. The authors' work will contribute to more intensive understanding on synthesizing phosphine-protected nanoclusters as well as shedding light on the structure-property correlations in the nanocluster range.
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937Chakraborty, I.; Pradeep, T. Atomically precise clusters of noble metals: Emerging link between atoms and nanoparticles. Chem. Rev. 2017, 117, 8208– 8271, DOI: 10.1021/acs.chemrev.6b00769Google Scholar937https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpt1Cnu70%253D&md5=a4715fc394d2a15e47d448929ad223d7Atomically Precise Clusters of Noble Metals: Emerging Link between Atoms and NanoparticlesChakraborty, Indranath; Pradeep, ThalappilChemical Reviews (Washington, DC, United States) (2017), 117 (12), 8208-8271CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. Atomically precise pieces of matter of nanometer dimensions composed of noble metals are new categories of materials with many unusual properties. Over 100 mols. of this kind with formulas such as Au25(SR)18, Au38(SR)24, and Au102(SR)44 as well as Ag25(SR)18, Ag29(S2R)12, and Ag44(SR)30 (often with a few counterions to compensate charges) are known now. They can be made reproducibly with robust synthetic protocols, resulting in colored solns., yielding powders or crystals. They are distinctly different from nanoparticles in their spectroscopic properties such as optical absorption and emission, showing well-defined features, just like mols. They show isotopically resolved mol. ion peaks in mass spectra and provide diverse information when examd. through multiple instrumental methods. Most important of these properties is luminescence, often in the visible-near-IR window, useful in biol. applications. Luminescence in the visible region, esp. by clusters protected with proteins, with a large Stokes shift, has been used for various sensing applications, down to a few tens of mols./ions, in air and water. Catalytic properties of clusters, esp. oxidn. of org. substrates, have been examd. Materials science of these systems presents numerous possibilities and is fast evolving. Computational insights have given reasons for their stability and unusual properties. The mol. nature of these materials is unequivocally manifested in a few recent studies such as intercluster reactions forming precise clusters. These systems manifest properties of the core, of the ligand shell, as well as that of the integrated system. They are better described as protected mols. or aspicules, where aspis means shield and cules refers to mols., implying that they are "shielded mols.". In order to understand their diverse properties, a nomenclature has been introduced with which it is possible to draw their structures with positional labels on paper, with some training. Research in this area is captured here, based on the publications available up to Dec. 2016.
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938Jin, R.; Zeng, C.; Zhou, M.; Chen, Y. Atomically precise colloidal metal nanoclusters and nanoparticles: Fundamentals and opportunities. Chem. Rev. 2016, 116, 10346– 10413, DOI: 10.1021/acs.chemrev.5b00703Google Scholar938https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVeksLnJ&md5=aa1208c72c4e8de1be9a4a906a9bc6c9Atomically Precise Colloidal Metal Nanoclusters and Nanoparticles: Fundamentals and OpportunitiesJin, Rongchao; Zeng, Chenjie; Zhou, Meng; Chen, YuxiangChemical Reviews (Washington, DC, United States) (2016), 116 (18), 10346-10413CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. Colloidal nanoparticles are being intensely pursued in current nanoscience research. Nanochemists are often frustrated by the known fact that no two nanoparticles are the same, which precludes the deep understanding of many fundamental properties of colloidal nanoparticles in which the total structures (core plus surface) must be known. Therefore, controlling nanoparticles with at. precision and solving their total structures have long been major dreams for nanochemists. Recently, these goals are partially fulfilled in the case of gold nanoparticles, at least in the ultrasmall size regime (1-3 nm in diam., often called nanoclusters). This review summarizes the major progress in the field, including the principles that permit atomically precise synthesis, new types of at. structures, and unique phys. and chem. properties of atomically precise nanoparticles, as well as exciting opportunities for nanochemists to understand very fundamental science of colloidal nanoparticles (such as the stability, metal-ligand interfacial bonding, ligand assembly on particle surfaces, aesthetic structural patterns, periodicities, and emergence of the metallic state) and to develop a range of potential applications such as in catalysis, biomedicine, sensing, imaging, optics, and energy conversion. Although most of the research activity currently focuses on thiolate-protected gold nanoclusters, important progress also was achieved in other ligand-protected gold, silver, and bimetal (or alloy) nanoclusters. All of these types of unique nanoparticles will bring unprecedented opportunities, not only in understanding the fundamental questions of nanoparticles but also in opening up new horizons for scientific studies of nanoparticles.
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939Kang, X.; Zhu, M. Tailoring the photoluminescence of atomically precise nanoclusters. Chem. Soc. Rev. 2019, 48, 2422– 2457, DOI: 10.1039/C8CS00800KGoogle Scholar939https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkt1Wqt7k%253D&md5=a25d2e3afdc1a6d81551c0edc0d36b02Tailoring the photoluminescence of atomically precise nanoclustersKang, Xi; Zhu, ManzhouChemical Society Reviews (2019), 48 (8), 2422-2457CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Due to their atomically precise structures and intriguing chem./phys. properties, metal nanoclusters are an emerging class of modular nanomaterials. Photo-luminescence (PL) is one of their most fascinating properties, due to the plethora of promising PL-based applications, such as chem. sensing, bio-imaging, cell labeling, phototherapy, drug delivery, and so on. However, the PL of most current nanoclusters is still unsatisfactory-the PL quantum yield (QY) is relatively low (generally lower than 20%), the emission lifetimes are generally in the nanosecond range, and the emitted color is always red (emission wavelengths of above 630 nm). To address these shortcomings, several strategies have been adopted, and are reviewed herein: capped-ligand engineering, metallic kernel alloying, aggregation-induced emission, self-assembly of nanocluster building blocks into cluster-based networks, and adjustments on external environment factors. We further review promising applications of these fluorescent nanoclusters, with particular focus on their potential to impact the fields of chem. sensing, bio-imaging, and bio-labeling. Finally, scope for improvements and future perspectives of these novel nanomaterials are highlighted as well. Our intended audience is the broader scientific community interested in the fluorescence of metal nanoclusters, and our review hopefully opens up new horizons for these scientists to manipulate PL properties of nanoclusters. This review is based on publications available up to Dec. 2018.
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940Li, Y.-L.; Wang, Z.-Y.; Ma, X.-H.; Luo, P.; Du, C.-X.; Zang, S.-Q. Distinct photophysical properties in atom-precise silver and copper nanocluster analogues. Nanoscale 2019, 11, 5151– 5157, DOI: 10.1039/C9NR01058KGoogle Scholar940https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXktVCmurs%253D&md5=62b8c55baa888c0073a3fb1063e6563eDistinct photophysical properties in atom-precise silver and copper nanocluster analoguesLi, Yan-Ling; Wang, Zhao-Yang; Ma, Xiao-Hong; Luo, Peng; Du, Chen-Xia; Zang, Shuang-QuanNanoscale (2019), 11 (12), 5151-5157CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The synthesis of atom-precise analogs of homometallic nanoclusters remains a great challenge. Herein we report the first pair of atom-precise copper/silver-thiolate halide cluster analogs, namely [Cu17/Ag17I3S(C2B10H10S2)6(CH3CN)11] (Cu17 and Ag17), obtained by bottom-up self-assembly and complete-metal-exchange-induced cluster-to-cluster transformation, resp. The differences in optical absorption and emission of these analogs were fully elucidated by exptl. and theor. methods.
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941Nasaruddin, R. R.; Chen, T.; Yan, N.; Xie, J. Roles of thiolate ligands in the synthesis, properties and catalytic application of gold nanoclusters. Coord. Chem. Rev. 2018, 368, 60– 79, DOI: 10.1016/j.ccr.2018.04.016Google Scholar941https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXosFGrt7w%253D&md5=b762e9867a2f611d44d8d0c0212bc2fcRoles of thiolate ligands in the synthesis, properties and catalytic application of gold nanoclustersNasaruddin, Ricca Rahman; Chen, Tiankai; Yan, Ning; Xie, JianpingCoordination Chemistry Reviews (2018), 368 (), 60-79CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)Ultrasmall (<2 nm) ligand-protected metal nanoclusters (NCs) have been an emerging class of functional materials with rich coordination chem., finding increasing acceptance in both basic and applied research owing to their at. precision, well-defined mol. structure, and intriguing mol.-like properties. The presence of ligands on metal NCs is crucial not only for maintaining their at. precision and well-defined structure, but also for their rich coordination chem. with noble metals, influencing the synthesis, and physicochem. and catalytic properties of metal NCs. In this review, we discuss the important roles of ligands to metal NCs, taking water-sol. gold nanoclusters (Au NCs) as an example. The review covers the fundamental understandings (and advances) on the roles of ligands to water-sol. Au NCs in the synthesis (e.g., influencing the size and formation rate, and revealing the growth mechanisms), physicochem. properties (e.g., geometrical structure, chirality, stability, soly., and electronic, photoluminescence and biol. properties) and catalytic applications (e.g., accessibility, activity, selectivity, and coordination of catalytic mechanism of quasi-homogeneous catalysts and immobilization of heterogeneous catalysts). The review also highlights some challenging issues on how ligands and ligand engineering could expand the scope of metal NCs in the synthesis, physicochem. properties, and catalytic application.
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942Liu, X.; Astruc, D. Atomically precise copper nanoclusters and their applications. Coord. Chem. Rev. 2018, 359, 112– 126, DOI: 10.1016/j.ccr.2018.01.001Google Scholar942https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXht1Sjtrk%253D&md5=62152b449191eff83164aa40dca783c6Atomically precise copper nanoclusters and their applicationsLiu, Xiang; Astruc, DidierCoordination Chemistry Reviews (2018), 359 (), 112-126CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)A review. Although Cu nanoparticles (CuNPs) have been subjected to broad investigations, esp. viewing their easy access, low cost and rich catalytic properties, atomically precise copper nanoclusters (CuNCs) are less often examd. due to the difficulties of their isolation in pure form. Yet their study is essential for a better understanding of the mol., phys. and catalytic properties of CuNPs that are in fact mixts. of CuNCs. The review highlights the background and recent progress in CuNCs including the structural and physico-chem. properties and new applications to galvanic reactions, fluorescence and catalysis. Particular emphasis is placed on catalysis for which hydrogen evolution reaction, redn. of CO2 and recent comparative results from our group concerning 1,3-dipolar cycloaddn. of org. azides and alkynes (CuAAC, "click reaction") are detailed. In this latter sub-field the key role of the relative stabilities of the CuNCs on their performances is emphasized as shown with Clayborne and Chen's nanocluster anion [Cu6(SR)6]- [Na+, solvent], R=C7H4NO, solvent=acetone or THF, that shows excellent efficiency for the CuAAC reaction.
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943Fang, J.; Zhang, B.; Yao, Q.; Yang, Y.; Xie, J.; Yan, N. Recent advances in the synthesis and catalytic applications of ligand-protected, atomically precise metal nanoclusters. Coord. Chem. Rev. 2016, 322, 1– 29, DOI: 10.1016/j.ccr.2016.05.003Google Scholar943https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XotlCkurk%253D&md5=efeaba33202118deaed818837d25a0b1Recent advances in the synthesis and catalytic applications of ligand-protected, atomically precise metal nanoclustersFang, Jun; Zhang, Bin; Yao, Qiaofeng; Yang, Yang; Xie, Jianping; Yan, NingCoordination Chemistry Reviews (2016), 322 (), 1-29CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)A review. Due to their excellent catalytic properties under mild reaction conditions, well-defined, nanosized noble metal catalysts have potential applications in the manuf. of fine chems., pharmaceuticals, and food additives. Ligand stabilized MnLm NCs (M: noble metal; n: no. of metal atoms, n < 150; L: ligand; m: no. of ligands) have a long history in catalysis, but recent advances in synthetic strategies and instrumental characterization have led to a renaissance in the catalytic applications of MnLm NCs. Thus, NCs can serve as model catalysts for understanding fundamental aspects of catalysis, but they also exhibit interesting properties in practical applications. MnLm NCs such as the recently investigated thiolated capped Au NCs have unique geometric structures with ultra-small size and strong quantum confinement, both of which are lacking in larger noble metal nanoparticles (>2 nm). The correlations among the catalytic performance of MnLm NCs with the size, structure, and compn. of individual NCs at the at. level can be demonstrated in realistic ambient reaction conditions, thereby contributing to the rational design of highly active catalysts with novel properties. Our current understanding of these newly emerging catalytic NCs is still in its infancy, but some studies have shown their potential for promoting new types of reactions. This review summarizes recent exciting advances in this field (since 2010), esp. the catalytic properties of noble metal NCs in the presence of the ligand shell and after removing the ligand.
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944Kang, X.; Chong, H.; Zhu, M. Au25(SR)18: The captain of the great nanocluster ship. Nanoscale 2018, 10, 10758– 10834, DOI: 10.1039/C8NR02973CGoogle Scholar944https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXpvVChtbg%253D&md5=bb905f0c5cc71c68584323669ca7a4cdAu25(SR)18: the captain of the great nanocluster shipKang, Xi; Chong, Hanbao; Zhu, ManzhouNanoscale (2018), 10 (23), 10758-10834CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Noble metal nanoclusters are in the intermediate state between discrete atoms and plasmonic nanoparticles and are of significance due to their atomically accurate structures, intriguing properties, and great potential for applications in various fields. In addn., the size-dependent properties of nanoclusters construct a platform for thoroughly researching the structure (compn.)-property correlations, which is favorable for obtaining novel nanomaterials with enhanced physicochem. properties. Thus far, more than 100 species of nanoclusters (mono-metallic Au or Ag nanoclusters, and bi- or tri-metallic alloy nanoclusters) with crystal structures have been reported. Among these nanoclusters, Au25(SR)18-the brightest mol. star in the nanocluster field-is capable of revealing the past developments and prospecting the future of the nanoclusters. Since being successfully synthesized (in 1998, with a 20-yr history) and structurally detd. (in 2008, with a 10-yr history), Au25(SR)18 has stimulated the interest of chemists as well as material scientists, due to the early discovery, easy prepn., high stability, and easy functionalization and application of this mol. star. In this review, the prepn. methods, crystal structures, physicochem. properties, and practical applications of Au25(SR)18 are summarized. The properties of Au25(SR)18 range from optics and chirality to magnetism and electrochem., and the property-oriented applications include catalysis, chem. imaging, sensing, biol. labeling, biomedicine and beyond. Furthermore, the research progress on the Ag-based M25(SR)18 counterpart (i.e., Ag25(SR)18) is included in this review due to its homologous compn., construction and optical absorption to its gold-counterpart Au25(SR)18. Moreover, the alloying methods, metal-exchange sites and property alternations based on the templated Au25(SR)18 are highlighted. Finally, some perspectives and challenges for the future research of the Au25(SR)18 nanocluster are proposed (also holding true for all members in the nanocluster field). This review is directed toward the broader scientific community interested in the metal nanocluster field, and hopefully opens up new horizons for scientists studying nanomaterials. This review is based on the publications available up to March 2018.
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945Yang, J.; Jin, R. New advances in atomically precise silver nanoclusters. ACS Mater. Lett. 2019, 1, 482– 489, DOI: 10.1021/acsmaterialslett.9b00246Google Scholar945https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhslWnurfJ&md5=fc5e6fcd73a15a1764206a2c126e7774New Advances in Atomically Precise Silver NanoclustersYang, Jie; Jin, RongchaoACS Materials Letters (2019), 1 (4), 482-489CODEN: AMLCEF; ISSN:2639-4979. (American Chemical Society)A review. Atomically precise noble metal nanoclusters are ultrasmall particles that are typically composed of tens to hundreds of metal atoms in the core (equiv. sizes 1-3 nm). This new class of nanomaterials is unique in that they are atomically precise and possess uniform structures, high stability, and attractive properties. Built on the significant success of Au nanoclusters, Ag nanoclusters have recently received increasing attention. The majority of reported silver nanocluster sizes exhibit mol.-like properties, whereas larger ones exhibit plasmons characteristic of metallic state (as opposed to mol. state in smaller sizes). Both mol. (i.e., nonmetallic) and metallic nanoclusters hold promise in a wide range of applications. To deepen the understanding of their phys. and chem. properties, precise control over size and detn. of the crystal structure are the top priorities. In recent developments, dozens of silver nanoclusters with definite formulas have been prepd. through various strategies, albeit the structural detn. still lags behind. In this short Review, we summarize the recent progress in ligand-protected silver nanoclusters, including the size-focusing synthetic methods, new sizes, structures, and properties.
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946Christensen, S. L.; MacDonald, M. A.; Chatt, A.; Zhang, P.; Qian, H.; Jin, R. Dopant location, local structure, and electronic properties of Au24Pt(SR)18 nanoclusters. J. Phys. Chem. C 2012, 116, 26932– 26937, DOI: 10.1021/jp310183xGoogle Scholar946https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslOls7jL&md5=235d33f67b95ebaa7d898195fb076b70Dopant Location, Local Structure, and Electronic Properties of Au24Pt(SR)18 NanoclustersChristensen, Stephen L.; MacDonald, Mark A.; Chatt, Amares; Zhang, Peng; Qian, Huifeng; Jin, RongchaoJournal of Physical Chemistry C (2012), 116 (51), 26932-26937CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We report element-specific X-ray spectroscopy results on the structure and bonding of Au24Pt, a thiolate-protected bimetallic nanocluster. Platinum L3-edge extended X-ray absorption fine-structure (EXAFS) data, in assocn. with XPS compositional anal., was used to identify the location of the Pt dopant to be in the center of the icosahedron Au13 core. Comparison of Au24Pt with the structure of Au25 by gold L3-edge EXAFS clearly shows contraction of both metal-thiolate and metal-metal bond distances, caused by Pt doping. The doping effect on the electronic properties of Au24Pt was further evaluated by high-resoln. Au 4f core-level XPS and ab initio calcns., which elucidate the importance of bimetallic (Pt-Au) bonding and bond contraction effects on the properties of Pt-doped thiolate-gold nanoclusters.
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947Faraday, M. X. The Bakerian Lecture.—Experimental relations of gold (and other metals) to light. Philos. Trans. 1857, 145– 181Google ScholarThere is no corresponding record for this reference.
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948Heaven, M. W.; Dass, A.; White, P. S.; Holt, K. M.; Murray, R. W. Crystal structure of the gold nanoparticle [N(C8H17)4][Au25(SCH2CH2Ph)18]. J. Am. Chem. Soc. 2008, 130, 3754– 3755, DOI: 10.1021/ja800561bGoogle Scholar948https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXivVSktLY%253D&md5=0240b5da3df098e66d93a8ed812a84feCrystal Structure of the Gold Nanoparticle [N(C8H17)4][Au25(SCH2CH2Ph)18]Heaven, Michael W.; Dass, Amala; White, Peter S.; Holt, Kennedy M.; Murray, Royce W.Journal of the American Chemical Society (2008), 130 (12), 3754-3755CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors report the crystal structure of the thiolate Au nanoparticle [TOA+][Au25(SCH2CH2Ph)18-], where TOA+ = N(C8H17)4+. Crystallog. data are given. The crystal structure reveals three types of Au atoms: (a) one central Au atom whose coordination no. is 12 (12 bonds to Au atoms); (b) 12 Au atoms that form the vertexes of an icosahedron around the central atom, whose coordination no. is 6 (five bonds to Au atoms and one to a S atom), and (c) 12 Au atoms that are stellated on 12 of the 20 faces of the Au13 icosahedron. The arrangement of the latter Au atoms may be influenced by aurophilic bonding. Together they form six orthogonal semirings, or staples, of -Au2(SCH2CH2Ph)3- in an octahedral arrangement around the Au13 core.
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949Liu, Z.; Zhu, M.; Meng, X.; Xu, G.; Jin, R. Electron transfer between [Au25(SC2H4Ph)18]− TOA+ and oxoammonium cations. J. Phys. Chem. Lett. 2011, 2, 2104– 2109, DOI: 10.1021/jz200925hGoogle Scholar949https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpvFCju74%253D&md5=2af37eba2812633b5a362ac5e7ce5c7dElectron Transfer between [Au25(SC2H4Ph)18]-TOA+ and Oxoammonium CationsLiu, Zhao; Zhu, Manzhou; Meng, Xiangming; Xu, Guoyong; Jin, RongchaoJournal of Physical Chemistry Letters (2011), 2 (17), 2104-2109CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)We report intermol. electron transfer between 2,2,6,6-tetramethylpiperidin-1-oxoammonium tetrafluoroborate (TEMPO+BF4-) and thiol-stabilized [Au25(SC2H4Ph)18]-TOA+ (abbreviated as Au25-) nanoclusters. The TEMPO+ cations are generated by single electron oxidn. of piperidine aminoxyl radical TEMPO (2,2,6,6-tetramethylpiperidinyl-oxy). Cyclic voltammetry (CV) and ESR explicitly indicate that two consecutive single-electron transfer reactions occur between TEMPO+ cations and Au25- nanoclusters. NMR (1H NMR) anal. demonstrates that the methylene proton resonances of the thiolate ligands can also be used to monitor the redox process. UV-vis spectroscopic anal. reveals the changes in the absorption peaks of Au25 nanoclusters upon consecutive single-electron transfers between the nanoclusters and TEMPO+ cations. The ease of control over the redox process involving TEMPO+ allows the prepn. of pure Au25(SC2H4Ph)18+ nanoclusters. The interesting electron-donating properties of Au25(SR)18 clusters may find some promising applications in future studies.
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950Walter, M.; Akola, J.; Lopez-Acevedo, O.; Jadzinsky, P. D.; Calero, G.; Ackerson, C. J.; Whetten, R. L.; Grönbeck, H.; Häkkinen, H. A unified view of ligand-protected gold clusters as superatom complexes. Proc. Natl. Acad. Sci. U. S. A. 2008, 105, 9157– 9162, DOI: 10.1073/pnas.0801001105Google Scholar950https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosFaksLY%253D&md5=16b25c17a60dc8916f92cc01c71d505dA unified view of ligand-protected gold clusters as superatom complexesWalter, Michael; Akola, Jaakko; Lopez-Acevedo, Olga; Jadzinsky, Pablo D.; Calero, Guillermo; Ackerson, Christopher J.; Whetten, Robert L.; Gronbeck, Henrik; Hakkinen, HannuProceedings of the National Academy of Sciences of the United States of America (2008), 105 (27), 9157-9162CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chem. of nanomaterials. Factors driving the thermodn. stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles protected by thiolate (SR) or phosphine and halide (PR3, X) ligands. The picture has emerged from anal. of large-scale d. functional theory calcns. of structurally characterized compds., namely Au102(SR)44, Au39(PR3)14X6-, Au11(PR3)7X3, and Au13(PR3)10X23+, where X is either a halogen or a thiolate. Attributable to a compact, sym. core and complete steric protection, each compd. has a filled spherical electronic shell and a major energy gap to unoccupied states. Consequently, the exceptional stability is best described by a "noble-gas superatom" analogy. The explanatory power of this concept is shown by its application to many monomeric and oligomeric compds. of precisely known compn. and structure, and its predictive power is indicated through suggestions offered for a series of anomalously stable cluster compns. which are still awaiting a precise structure detn.
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951Grönbeck, H. Correspondence: On the bonding in ligand-protected gold clusters. Nat. Commun. 2017, 8, 1612, DOI: 10.1038/s41467-017-01292-yGoogle Scholar951https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M3hs1Khtg%253D%253D&md5=01512e82bed86f7214c92f0e4296f3a6Correspondence: On the bonding in ligand-protected gold clustersGronbeck HenrikNature communications (2017), 8 (1), 1612 ISSN:.There is no expanded citation for this reference.
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952Zeng, C.; Qian, H.; Li, T.; Li, G.; Rosi, N. L.; Yoon, B.; Barnett, R. N.; Whetten, R. L.; Landman, U.; Jin, R. Total structure and electronic properties of the gold nanocrystal Au36(SR)24. Angew. Chem., Int. Ed. 2012, 51, 13114– 13118, DOI: 10.1002/anie.201207098Google Scholar952https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1OgtrfE&md5=4b4410495294e447b83023c22eb302d4Total Structure and Electronic Properties of the Gold Nanocrystal Au36(SR)24Zeng, Chenjie; Qian, Huifeng; Li, Tao; Li, Gao; Rosi, Nathaniel L.; Yoon, Bokwon; Barnett, Robert N.; Whetten, Robert L.; Landman, Uzi; Jin, RongchaoAngewandte Chemie, International Edition (2012), 51 (52), 13114-13118CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors report the discovery of an fcc.-type core structure in Au36(SR)24, where SR refers to 4-tert-butylbenzenethiolate. The emergence of an fcc. structure in Au36(SR)24 is surprising, given the small size of the cluster. The total structure was detd. and theor. insights into its bonding and electronic structure are given. The structures and stability of nanoclusters are detd. by a balance between maximization of the metal (gold) cohesive energy and the electronic effect of the conjugated thiolate. A large (approx. 1.7 eV) HOMO-LUMO energy gap confers extreme stability, and originates from the (superatom) shell-structure organization of the electronic energy levels of the cluster.
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953Jin, R.; Nobusada, K. Doping and alloying in atomically precise gold nanoparticles. Nano Res. 2014, 7, 285– 300, DOI: 10.1007/s12274-014-0403-5Google Scholar953https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXht12jsL8%253D&md5=4d9870aa12729870427d0a9aa592f239Doping and alloying in atomically precise gold nanoparticlesJin, Rongchao; Nobusada, KatsuyukiNano Research (2014), 7 (3), 285-300CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)A review. The recent success in the synthesis and total structure detn. of atomically precise gold nanoparticles has provided exciting opportunities for fundamental studies as well as the development of new applications. These unique nanoparticles are of mol. purity and possess well defined formulas (i.e., specific nos. of metal atoms and ligands), resembling org. compds. Crystn. of such molecularly pure nanoparticles into macroscopic single crystals allows for the detn. of total structures of nanoparticles (i.e., the arrangement of metal core atoms and surface ligands) by X-ray crystallog. In this perspective article, we summarize recent efforts in doping and alloying gold nanoparticles with other metals, including Pd, Pt, Ag and Cu. With atomically precise gold nanoparticles, a specific no. of foreign atoms (e.g., Pd, Pt) can be incorporated into the gold core, whereas a range of Ag and Cu substitutions is obsd. but, interestingly, the total no. of metal atoms in the homogold nanoparticle is preserved. The heteroatom substitution of gold nanoparticles allows one to probe the optical, structural, and electronic properties truly at the single-atom level, and thus provides a wealth of information for understanding the intriguing properties of this new class of nanomaterials. [Figure not available: see fulltext.].
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954Negishi, Y.; Munakata, K.; Ohgake, W.; Nobusada, K. Effect of copper doping on electronic structure, geometric structure, and stability of thiolate-protected Au25 nanoclusters. J. Phys. Chem. Lett. 2012, 3, 2209– 2214, DOI: 10.1021/jz300892wGoogle Scholar954https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFWhs7fM&md5=bf1bb140218d9f99b90cca66a513fae0Effect of Copper Doping on Electronic Structure, Geometric Structure, and Stability of Thiolate-Protected Au25 NanoclustersNegishi, Yuichi; Munakata, Kenta; Ohgake, Wataru; Nobusada, KatsuyukiJournal of Physical Chemistry Letters (2012), 3 (16), 2209-2214CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Several recent studies have attempted to impart [Au25(SR)18]- with new properties by doping with foreign atoms. The effect of Cu doping on the electronic and geometric structures and stability of [Au25(SR)18]- were studied, with the aim of studying the effect of foreign atom doping of [Au25(SR)18]-. CunAu25-n(SC2H4Ph)18 (n = 1-5) was synthesized by reducing complexes formed by the reaction between metal salts (Cu and Au salts) and PhC2H4SH with NaBH4. Mass anal. revealed that the products contained CunAu25-n(SC2H4Ph)18 (n = 1-5) in high purity. Exptl. and theor. anal. of the synthesized clusters revealed that Cu doping alters the optical properties and redox potentials of the cluster, greatly distorts its geometric structure, and reduces the cluster stability in soln. These findings are expected to be useful for developing design guidelines for functionalizing [Au25(SR)18]- through doping with foreign atoms.
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955Negishi, Y.; Iwai, T.; Ide, M. Continuous modulation of electronic structure of stable thiolate-protected Au25 cluster by Ag doping. Chem. Commun. 2010, 46, 4713– 4715, DOI: 10.1039/c0cc01021aGoogle Scholar955https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXnslSntbw%253D&md5=ccdf3f8b6934c858fd2e7e911e3c4db1Continuous modulation of electronic structure of stable thiolate-protected Au25 cluster by Ag dopingNegishi, Yuichi; Iwai, Takeyuki; Ide, MaoChemical Communications (Cambridge, United Kingdom) (2010), 46 (26), 4713-4715CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The effect of Ag doping on the electronic structure of a stable thiolate-protected Au25 cluster (Au25(SR)18) was studied by measuring the optical spectra of Au25-nAgn(SC12H25)18 (n = 0-11) and the electronic structure of Au25(SC12H25)18 is sensitive to Ag doping and is continuously modulated by incorporation of Ag atoms.
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956Ghosh, A.; Mohammed, O. F.; Bakr, O. M. Atomic-Level Doping of Metal Clusters. Acc. Chem. Res. 2018, 51, 3094– 3103, DOI: 10.1021/acs.accounts.8b00412Google Scholar956https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1Wlu7bO&md5=7257881c9d3a9f062a629f3c6b679228Atomic-Level Doping of Metal ClustersGhosh, Atanu; Mohammed, Omar F.; Bakr, Osman M.Accounts of Chemical Research (2018), 51 (12), 3094-3103CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)Atomically precise noble metal (mainly silver and gold) nanoclusters are an emerging category of promising functional materials for future applications in energy, sensing, catalysis, and nanoelectronics. These nanoclusters are protected by ligands such as thiols, phosphines, and hydride and have sizes between those of atoms and plasmonic nanoparticles. In metallurgy, the properties of a pure metal are modified by the addn. of other metals, which often offers augmented characteristics, making them more utilizable for real-life applications. In this Account, we discuss how the incorporation of various metal atoms into existing protected nanoclusters tunes their structure and properties.The process of incorporating metals into an existing cluster is known as doping; the product is known as a doped cluster, and the incorporated metal atom is called a dopant/foreign atom. We first present a brief historical overview of protected clusters and the need for doping and explain (with examples) the difference between an "alloy" and a "doped" cluster, which are two frequently confused terms. We then discuss several commonly obsd. challenges in the synthesis of doped clusters: (i) doping produces a mixt. of compns. that prevents the growth of single crystals; (ii) doping with foreign atoms sometimes changes the overall compn. and structure of the parent cluster; and (iii) doping beyond a certain no. of foreign atoms decomps. the doped cluster. After delineating the challenges, we review a few potential synthetic methods for doped clusters: (i) the co-redn. method, (ii) the galvanic exchange method, (iii) ligand-induced conversion of bimetallic clusters to doped clusters, and (iv) intercluster reactions.As a foreign atom is able to occupy different positions within the structure of the parent cluster, we examine the structural relationship between the parent clusters and their different foreign-atom-doped clusters. We then show how doping enhances the stability, luminescence, and catalytic properties of clusters. The enhancement factor highly depends on the no. and nature of the foreign atoms, which can also alter the charge state of the parent cluster.Atomic-level doping of foreign atoms in the parent cluster is confirmed by high-resoln. electrospray ionization and matrix-assisted laser desorption ionization mass spectrometry techniques and single-crystal X-ray diffraction methods. The photophys. properties of the doped clusters are investigated using both time-dependent and steady-state luminescence and optical absorption spectroscopies.After presenting an overview of at.-level doping in metal clusters and demonstrating its importance for enriching the chem. and photophysics of clusters and extending their applications, we conclude this Account with a brief perspective on the field's future.
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957Negishi, Y.; Kurashige, W.; Niihori, Y.; Iwasa, T.; Nobusada, K. Isolation, structure, and stability of a dodecanethiolate-protected Pd1Au24 cluster. Phys. Chem. Chem. Phys. 2010, 12, 6219– 6225, DOI: 10.1039/b927175aGoogle Scholar957https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvVWrs7o%253D&md5=497da89542b2b4d7359b52e818411e57Isolation, structure, and stability of a dodecanethiolate-protected Pd1Au24 clusterNegishi, Yuichi; Kurashige, Wataru; Niihori, Yoshiki; Iwasa, Takeshi; Nobusada, KatsuyukiPhysical Chemistry Chemical Physics (2010), 12 (23), 6219-6225CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)A dodecanethiolate-protected Pd1Au24(SC12H25)18 cluster, which is a mono-Pd-doped cluster of the well understood magic gold cluster Au25(SR)18, was isolated in high purity using solvent fractionation and high-performance liq. chromatog. (HPLC) after the prepn. of dodecanethiolate-protected palladium-gold bimetal clusters. The cluster thus isolated was identified as the neutral [Pd1Au24(SC12H25)18]0 from the retention time in reverse phase columns and by elemental analyses. The LDI mass spectrum of [Pd1Au24(SC12H25)18]0 indicates that [Pd1Au24(SC12H25)18]0 adopts a similar framework structure to Au25(SR)18, in which an icosahedral Au13 core is protected by six [-S-Au-S-Au-S-] oligomers. The optical absorption spectrum of [Pd1Au24(SC12H25)18]0 exhibits peaks at ∼690 and ∼620 nm, which is consistent with calcd. results on [Pd1Au24(SC1H3)18]0 in which the central gold atom of Au25(SC1H3)18 is replaced with Pd. These results strongly indicate that the isolated [Pd1Au24(SC12H25)18]0 has a core-shell [Pd1@Au24(SC12H25)18]0 structure in which the central Pd atom is surrounded by a frame of Au24(SC12H25)18. Expts. on the stability of the cluster showed that Pd1@Au24(SC12H25)18 is more stable against degrdn. in soln. and laser dissocn. than Au25(SC12H25)18. These results indicate that the doping of a central atom is a powerful method to increase the stability beyond the Au25(SR)18 cluster.
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958Kacprzak, K. A.; Lehtovaara, L.; Akola, J.; Lopez-Acevedo, O.; Häkkinen, H. A density functional investigation of thiolate-protected bimetal PdAu24(SR)18z clusters: Doping the superatom complex. Phys. Chem. Chem. Phys. 2009, 11, 7123– 7129, DOI: 10.1039/b904491dGoogle Scholar958https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXpslels70%253D&md5=6f938a77f85b0cfac037128e7f8849f7A density functional investigation of thiolate-protected bimetal PdAu24(SR)18z clusters: doping the superatom complexKacprzak, Katarzyna A.; Lehtovaara, Lauri; Akola, Jaakko; Lopez-Acevedo, Olga; Haekkinen, HannuPhysical Chemistry Chemical Physics (2009), 11 (33), 7123-7129CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Structure, electronic properties, optical absorption and charging properties of methylthiolate-protected bimetal PdAu24(SR)18z (R = Me) clusters with various charge states (-3 ≤z≤ +3) are investigated by using d. functional theory. The results are compared to properties of the well-understood singly anionic pure gold complex Au25(SR)18(-1). The at. structure of this all-gold complex can be written in a "divide-and-protect" way as Au13[Au2(SR)3]6(-1) where 6 v-shaped Au2(SR)3 ligands protect the close-to-icosahedral Au13 core and where eight delocalized metal electrons, derived from Au(6s) electrons, comprise a stable closed-shell 1S21P6"superatom" configuration in the core. We show that the di-anion PdAu24(SR)18(-2) is a corresponding eight-electron closed-shell species whereas the clusters PdAu24(SR)18z, -1 ≤z≤ +3, have holes in the 1P HOMO manifold. This indicates that the doping Pd atom remains close to the zero-valent 4d105s0 configuration and does not contribute electrons to the delocalized electron d. in the gold core. Structural optimization shows that the all-gold "divide-and-protect" structure motif is robust with respect to replacing the Au by Pd at the center of the core, at the surface of the core or in one of the protecting Au2(SR)3 ligands. However, optical absorption and the HOMO-LUMO and electrochem. gaps depend sensitively on the site of the doping Pd atom, which may turn out be useful for assigning the structure of PdAu24(SR)18 from exptl. data.
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959Jiang, D.-e.; Dai, S. From superatomic Au25(SR)18– to superatomic M@Au24(SR)18q core–shell clusters. Inorg. Chem. 2009, 48, 2720– 2722, DOI: 10.1021/ic8024588Google Scholar959https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitFymurg%253D&md5=caabf4b34c8fb0942609452f6b18c04dFrom Superatomic Au25(SR)18- to Superatomic M@Au24(SR)18q Core-Shell ClustersJiang, De-en; Da, ShengInorganic Chemistry (2009), 48 (7), 2720-2722CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Au25(SR)18- belongs to a new type of superatom that features an icosahedral Au13 core-shell structure and a protective layer of six RS(Au-SR)2 motifs. This superatom has a magic no. of 8 free electrons that fully fill the 1s and 1p levels of the electron-shell model. By applying this superatom concept to the core-substitution chem. of Au25(SR)18-, we first scanned the periodic table for the potential core atom M by applying a simple rule derived from the 8-electron count and then optimized the selected candidates by d. functional theory calcns. to create many series of M@Au24(SR)18q core-shell nanoclusters. We found that 16 elements from groups 1, 2, and 10-14 of the periodic table can maintain both electronic and geometric structures of the original Au25(SR)18- magic cluster, indicating that the electron-counting rule based on the superatom concept is powerful in predicting viable M@Au24(SR)18q clusters. Our work opens up a promising area for exptl. exploration.
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960Qian, H.; Jiang, D.-e.; Li, G.; Gayathri, C.; Das, A.; Gil, R. R.; Jin, R. Monoplatinum doping of gold nanoclusters and catalytic application. J. Am. Chem. Soc. 2012, 134, 16159– 16162, DOI: 10.1021/ja307657aGoogle Scholar960https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlygtLnL&md5=c84987ca82307cb22766c05382024719Monoplatinum Doping of Gold Nanoclusters and Catalytic ApplicationQian, Huifeng; Jiang, De-en; Li, Gao; Gayathri, Chakicherla; Das, Anindita; Gil, Roberto R.; Jin, RongchaoJournal of the American Chemical Society (2012), 134 (39), 16159-16162CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report single-atom doping of gold nanoclusters (NCs), and its drastic effects on the optical, electronic, and catalytic properties, using the 25-atom system as a model. In our synthetic approach, a mixt. of Pt1Au24(SC2H4Ph)18 and Au25(SC2H4Ph)18 was produced via a size-focusing process, and then Pt1Au24(SC2H4Ph)18 NCs were obtained by selective decompn. of Au25(SC2H4Ph)18 in the mixt. with concd. H2O2 followed by purifn. via size-exclusion chromatog. Exptl. and theor. analyses confirmed that Pt1Au24(SC2H4Ph)18 possesses a Pt-centered icosahedral core capped by six Au2(SC2H4Ph)3 staples. The Pt1Au24(SC2H4Ph)18 cluster exhibits greatly enhanced stability and catalytic activity relative to Au25(SC2H4Ph)18 but a smaller energy gap (Eg ≈ 0.8 eV vs 1.3 eV for the homogold cluster).
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961Fields-Zinna, C. A.; Crowe, M. C.; Dass, A.; Weaver, J. E.; Murray, R. W. Mass spectrometry of small bimetal monolayer-protected clusters. Langmuir 2009, 25, 7704– 7710, DOI: 10.1021/la803865vGoogle Scholar961https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnt1Wrsr0%253D&md5=569f1f37d5f513ec63deccc78d9cf882Mass Spectrometry of Small Bimetal Monolayer-Protected ClustersFields-Zinna, Christina A.; Crowe, Matthew C.; Dass, Amala; Weaver, Joshua E. F.; Murray, Royce W.Langmuir (2009), 25 (13), 7704-7710CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Monolayer-protected clusters were prepd. by procedures like those yielding Au25L18 (where L = -SCH2CH2Ph = -SC2Ph) but using, instead, mixts. of Au and Pd salts, as starting materials, with the intent of creating and characterizing Au25-xMxL18 clusters. Isolation of small nanoparticle product followed by partial ligand exchange to introduce thiolated poly(ethylene glycol) (SPEG = -S(CH2CH2O)5CH3) into the nanoparticle ligand shell enabled characterization of the Au25-xMxL18 content by pos. mode electrospray ionization mass spectrometry (ESI-MS). For synthetic feed mole ratios of Au:Pd of 9:1 and 13:12, electrospray spectra of the PEGylated MPCs showed that the reaction and isolation produce a mixt. of Au25(SC2Ph)18 and a mono-Pd nanoparticle Au24Pd(SC2Ph)18. A higher proportion of the mono-Pd nanoparticle is produced by the 13:12 mol ratio, and also when the thiol:metal ratio was lowered, according to ESI-MS and MALDI-TOF-MS. As the nanoparticle mixt. is enriched, by solvent fractionations, in Au24Pd(SC2Ph)18 relative to Au25(SC2Ph)18, the distinctive optical and electrochem. signatures of Au25(SC2Ph)18 are replaced by Au24Pd(SC2Ph)18 nanoparticle responses, which are very different, even though only one Au atom is replaced by a Pd atom.
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962Tofanelli, M. A.; Ni, T. W.; Phillips, B. D.; Ackerson, C. J. Crystal structure of the PdAu24(SR)180 superatom. Inorg. Chem. 2016, 55, 999– 1001, DOI: 10.1021/acs.inorgchem.5b02106Google Scholar962https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVGksr8%253D&md5=2e1ee7a93185d4cd252e3e67c68d792cCrystal Structure of the PdAu24(SR)180 SuperatomTofanelli, Marcus A.; Ni, Thomas W.; Phillips, Billy D.; Ackerson, Christopher J.Inorganic Chemistry (2016), 55 (3), 999-1001CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)The single-crystal X-ray structure of Pd-doped Au25(SR)18 was solved. The crystal structure reveals that in PdAu24(SR)18, the Pd atom is localized only to the centroid of the Au25(SR)18 cluster. This single-crystal X-ray structure shows that PdAu24(SR)180 is well conceptualized with the superatom theory. The PdAu24(SR)180 charge state is isoelectronic with Au25(SR)18+1 as detd. by a first order Jahn-Teller effect of similar magnitude and by electrochem. comparison. The previously reported increased stability of PdAu24(SR)18 can be rationalized in terms of Pd-Au bonds that are shorter than the Au-Au bonds in Au25(SR)18.
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963Negishi, Y.; Igarashi, K.; Munakata, K.; Ohgake, W.; Nobusada, K. Palladium doping of magic gold cluster Au38(SC2H4Ph)24: Formation of Pd2Au36(SC2H4Ph)24 with higher stability than Au38(SC2H4Ph)24. Chem. Commun. 2012, 48, 660– 662, DOI: 10.1039/C1CC15765EGoogle Scholar963https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1Srur%252FM&md5=1889c0736e65ab7a431cd1f1f57541cdPalladium doping of magic gold cluster Au38(SC2H4Ph)24: formation of Pd2Au36(SC2H4Ph)24 with higher stability than Au38(SC2H4Ph)24Negishi, Yuichi; Igarashi, Kozue; Munakata, Kenta; Ohgake, Wataru; Nobusada, KatsuyukiChemical Communications (Cambridge, United Kingdom) (2012), 48 (5), 660-662CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A phenylethanethiolate-protected Pd2Au36(SC2H4Ph)24 cluster, which is a two-Pd atom-doped cluster of the well studied magic gold cluster Au38(SC2H4Ph)24, was synthesized in high purity and its stability was studied. Pd2Au36(SC2H4Ph)24 is more stable than Au38(SC2H4Ph)24 against degrdn. in soln. and core etching by thiols.
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964Liu, X.; Yuan, J.; Yao, C.; Chen, J.; Li, L.; Bao, X.; Yang, J.; Wu, Z. Crystal and solution photoluminescence of MAg24(SR)18 (M = Ag/Pd/Pt/Au) nanoclusters and some implications for the photoluminescence mechanisms. J. Phys. Chem. C 2017, 121, 13848– 13853, DOI: 10.1021/acs.jpcc.7b01730Google Scholar964https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpsVeqt78%253D&md5=d73c920055df21ddaa3e1faa5fc43a16Crystal and Solution Photoluminescence of MAg24(SR)18(M = Ag/Pd/Pt/Au) Nanoclusters and Some Implications for the Photoluminescence MechanismsLiu, Xu; Yuan, Jinyun; Yao, Chuanhao; Chen, Jishi; Li, Lingling; Bao, Xiaoli; Yang, Jinlong; Wu, ZhikunJournal of Physical Chemistry C (2017), 121 (25), 13848-13853CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)MAg24(SR)18 (M = Ag/Pd/Pt/Au) nanoclusters (NCs) with similar core-inner shell-outer shell structures were prepd., and their crystal and soln. luminescence was studied. The core Ag atom replacement by the Pd/Pt/Au atom obviously tunes the geometric and electronic structures of Ag25(SR)18 NC. The crystal luminescence intensities sequence hints a core-atom-directing charge transfer from the ligands to the metal kernels. Both the calcd. NPA charge and the measured Aginnershell-Sterminal bond length support the proposed mechanism. Further expts. show the solvent influence on the NCs luminescence supported by the blue-shift of emissions of MAg24(SR)18 NCs and the solvent-dependent luminescence intensity sequences. Esp., for PtAg24(SR)18, the quantum yield is almost 100-fold greater in MeCN (18.6%) than in CH2Cl2 (0.2%). However, the emission wavelengths of NCs are barely influenced by the solvent type. This work indicates the importance of the core atom and the solvent to the luminescence of core-inner shell-outer shell Ag NCs, having important implications for the luminescence mechanisms and tuning of noble metal nanoparticles.
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965Yan, J.; Su, H.; Yang, H.; Malola, S.; Lin, S.; Häkkinen, H.; Zheng, N. Total structure and electronic structure analysis of doped thiolated silver [MAg24(SR)18]2– (M = Pd, Pt) clusters. J. Am. Chem. Soc. 2015, 137, 11880– 11883, DOI: 10.1021/jacs.5b07186Google Scholar965https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVygs7jK&md5=f3ce7b369dbd8949b1559419b3c6bc18Total Structure and Electronic Structure Analysis of Doped Thiolated Silver [MAg24(SR)18]2- (M = Pd, Pt) ClustersYan, Juanzhu; Su, Haifeng; Yang, Huayan; Malola, Sami; Lin, Shuichao; Hakkinen, Hannu; Zheng, NanfengJournal of the American Chemical Society (2015), 137 (37), 11880-11883CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)With the incorporation of Pd or Pt atoms, thiolated Ag-rich 25-metal-atom nanoclusters were successfully prepd. and structurally characterized for the first time. With a compn. of [PdAg24(SR)18]2- or [PtAg24(SR)18]2-, the obtained 25-metal-atom nanoclusters have a metal framework structure similar to that of widely investigated Au25(SR)18. In both clusters, a M@Ag12 (M = Pd, Pt) core is capped by six distorted dimeric -RS-Ag-SR-Ag-SR- units. However, the silver-thiolate overlayer gives rise to a geometric chirality at variance to Au25(SR)18. The effect of doping on the electronic structure was studied through measured optical absorption spectra and ab initio anal. This work demonstrates that modulating electronic structures by transition-metal doping is expected to provide effective means to manipulate electronic, optical, chem., and catalytic properties of thiolated noble metal nanoclusters.
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966Bootharaju, M. S.; Joshi, C. P.; Parida, M. R.; Mohammed, O. F.; Bakr, O. M. Templated atom-precise galvanic synthesis and structure elucidation of a [Ag24Au(SR)18]− nanocluster. Angew. Chem., Int. Ed. 2016, 55, 922– 926, DOI: 10.1002/anie.201509381Google Scholar966https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFenurvN&md5=f177df90293e32d87abcd52040997038Templated Atom-Precise Galvanic Synthesis and Structure Elucidation of a [Ag24Au(SR)18]- NanoclusterBootharaju, Megalamane S.; Joshi, Chakra P.; Parida, Manas R.; Mohammed, Omar F.; Bakr, Osman M.Angewandte Chemie, International Edition (2016), 55 (3), 922-926CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Synthesis of atom-precise alloy nanoclusters with uniform compn. is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag24Au(SR)18]- cluster (SR: thiolate) using a pure [Ag25(SR)18]- cluster as a template. Conversely, the direct synthesis of Ag24Au cluster leads to a mixt. of [Ag25-xAux(SR)18]-, x=1-8. Mass spectrometry and crystallog. of [Ag24Au(SR)18]- reveal the presence of the Au heteroatom at the Ag25 center, forming Ag24Au. The successful exchange of the central Ag of Ag25 with Au causes perturbations in the Ag25 crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag25 and Ag24Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single-atom level.
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967Bootharaju, M. S.; Joshi, C. P.; Parida, M. R.; Mohammed, O. F.; Bakr, O. M. Innentitelbild: Templated atom-precise galvanic synthesis and structure elucidation of a [Ag24Au(SR)18]− nanocluster (Angew. Chem. 3/2016). Angew. Chem. 2016, 128, 834– 834, DOI: 10.1002/ange.201511258Google ScholarThere is no corresponding record for this reference.
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968Van Der Linden, M.; Van Bunningen, A. J.; Amidani, L.; Bransen, M.; Elnaggar, H.; Glatzel, P.; Meijerink, A.; De Groot, F. M. Single Au atom doping of silver nanoclusters. ACS Nano 2018, 12, 12751– 12760, DOI: 10.1021/acsnano.8b07807Google Scholar968https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1CktrrL&md5=30b1a8ff037c73531341eab63e36ad05Single Au Atom Doping of Silver Nanoclustersvan der Linden, Marte; van Bunningen, Arnoldus J.; Amidani, Lucia; Bransen, Maarten; Elnaggar, Hebatalla; Glatzel, Pieter; Meijerink, Andries; de Groot, Frank M. F.ACS Nano (2018), 12 (12), 12751-12760CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Ag29 nanoclusters capped with lipoic acid (LA) can be doped with Au. The doped clusters show enhanced stability and increased luminescence efficiency. The authors attribute the higher quantum yield to an increase in the rate of radiative decay. With mass spectrometry, the Au-doped clusters consist predominantly of Au1Ag28(LA)123-. The clusters were characterized using x-ray absorption spectroscopy at the Au L3-edge. Both the extended absorption fine structure (EXAFS) and the near edge structure (XANES) in combination with electronic structure calcns. confirm that the Au dopant is preferentially located in the center of the cluster. A useful XANES spectrum can be recorded for lower concns., or in shorter time, than the more commonly used EXAFS. This makes XANES a valuable tool for structural characterization.
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969Khatun, E.; Bose, S.; Jash, M.; Pradeep, T. Atomically precise cluster-based white light emitters. J. Chem. Sci. 2018, 130, 147, DOI: 10.1007/s12039-018-1559-4Google ScholarThere is no corresponding record for this reference.
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970Mishra, D.; Lobodin, V.; Zhang, C.; Aldeek, F.; Lochner, E.; Mattoussi, H. Gold-doped silver nanoclusters with enhanced photophysical properties. Phys. Chem. Chem. Phys. 2018, 20, 12992– 13007, DOI: 10.1039/C7CP08682BGoogle Scholar970https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXnslSmtr8%253D&md5=135cc41f78b198c5636fe102ecb8f3a0Gold-doped silver nanoclusters with enhanced photophysical propertiesMishra, Dinesh; Lobodin, Vladislav; Zhang, Chengqi; Aldeek, Fadi; Lochner, Eric; Mattoussi, HediPhysical Chemistry Chemical Physics (2018), 20 (18), 12992-13007CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We detail the characterization of atomically precise, luminescent silver and gold bimetallic nanoclusters (Ag and AgAuNCs) grown in the presence of bidentate lipoic acid (LA, the oxidized form) and dihydrolipoic acid (DHLA, the reduced form) ligands. We found that while doping AuNCs with Ag or Cu precursors using up to a 50% molar fraction (during growth) did not lead to any photoluminescence enhancement, doping of AgNCs with Au resulted in a six-fold enhancement of the PL emission compared to undoped AgNCs. The effect of doping is also reflected in the optical absorption and PL excitation spectra of the gold-doped NCs (AgAuNCs), where a clear blue shift in the absorbance features with respect to the pure AgNCs has been measured. Mass spectrometry measurements using ESI-MS showed that the AgNCs and Au-doped AgNCs had the compns. Ag29(DHLA)12 and Ag28Au(DHLA)12, resp. The bimetallic nature of the AgAuNC cores was further supported by XPS measurements. Data showed that the binding energies of the Ag and Au atoms measured from the nanoclusters were shifted with respect to those of the Ag and Au metals. Furthermore, the change in the Ag binding energy was affected by the presence of Au atoms. DOSY-NMR measurements performed on both sets of nanoclusters yielded no change in the hydrodynamic radius measured for either set of NCs when capped with the same ligands.
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971Soldan, G.; Aljuhani, M. A.; Bootharaju, M. S.; AbdulHalim, L. G.; Parida, M. R.; Emwas, A. H.; Mohammed, O. F.; Bakr, O. M. Gold doping of silver nanoclusters: A 26-fold enhancement in the luminescence quantum yield. Angew. Chem., Int. Ed. 2016, 55, 5749– 5753, DOI: 10.1002/anie.201600267Google Scholar971https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XlvVagt7c%253D&md5=8e803fba2570f61d6cee38e140c7fedcGold Doping of Silver Nanoclusters: A 26-Fold Enhancement in the Luminescence Quantum YieldSoldan, Giada; Aljuhani, Maha A.; Bootharaju, Megalamane S.; AbdulHalim, Lina G.; Parida, Manas R.; Emwas, Abdul-Hamid; Mohammed, Omar F.; Bakr, Osman M.Angewandte Chemie, International Edition (2016), 55 (19), 5749-5753CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A high quantum yield (QY) of photoluminescence (PL) in nanomaterials is necessary for a wide range of applications. Unfortunately, the weak PL and moderate stability of atomically precise silver nanoclusters (NCs) suppress their utility. Herein, we accomplished a ≥26-fold PL QY enhancement of the Ag29(BDT)12(TPP)4 cluster (BDT: 1,3-benzenedithiol; TPP: triphenylphosphine) by doping with a discrete no. of Au atoms, producing Ag29-xAux(BDT)12(TPP)4, x=1-5. The Au-doped clusters exhibit an enhanced stability and an intense red emission around 660 nm. Single-crystal XRD, mass spectrometry, optical, and NMR spectroscopy shed light on the PL enhancement mechanism and the probable locations of the Au dopants within the cluster.
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972Kang, X.; Zhou, M.; Wang, S.; Jin, S.; Sun, G.; Zhu, M.; Jin, R. The tetrahedral structure and luminescence properties of Bi-metallic Pt1Ag28(SR)18(PPh3)4 nanocluster. Chem. Sci. 2017, 8, 2581– 2587, DOI: 10.1039/C6SC05104AGoogle Scholar972https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXksl2hug%253D%253D&md5=f6f3980086e5c40bb4d0b51e035dde2aThe tetrahedral structure and luminescence properties of bi-metallic Pt1Ag28(SR)18(PPh3)4 nanoclusterKang, Xi; Zhou, Meng; Wang, Shuxin; Jin, Shan; Sun, Guodong; Zhu, Manzhou; Jin, RongchaoChemical Science (2017), 8 (4), 2581-2587CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)The at.-structure characterization of alloy nanoclusters (NCs) remains challenging but is crucial in order to understand the synergism and develop new applications based upon the distinct properties of alloy NCs. Herein, we report the synthesis and X-ray crystal structure of the Pt1Ag28(S-Adm)18(PPh3)4 nanocluster with a tetrahedral shape. Pt1Ag28 was synthesized by reacting Pt1Ag24(SPhMe2)18 simultaneously with Adm-SH (1-adamantanethiol) and PPh3 ligands. A tetrahedral structure is found in the metal framework of Pt1Ag28 NC and an overall surface shell (Ag16S18P4), as well as discrete Ag4S6P1 motifs. The Pt1Ag12 kernel adopts a face-centered cubic (FCC) arrangement, which is obsd. for the first time in alloy nanoclusters in contrast to the commonly obsd. icosahedral structure of homogold and homosilver NCs. The Pt1Ag28 nanocluster exhibits largely enhanced photoluminescence (quantum yield QY = 4.9%, emission centered at ∼672 nm), whereas the starting material (Pt1Ag24 NC) is only weakly luminescent (QY = 0.1%). Insights into the nearly 50-fold enhancement of luminescence were obtained via the anal. of electronic dynamics. This study demonstrates the at.-level tailoring of the alloy nanocluster properties by controlling the structure.
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973Bootharaju, M. S.; Kozlov, S. M.; Cao, Z.; Harb, M.; Parida, M. R.; Hedhili, M. N.; Mohammed, O. F.; Bakr, O. M.; Cavallo, L.; Basset, J.-M. Direct versus ligand-exchange synthesis of [PtAg28(BDT)12(TPP)4]4– nanoclusters: Effect of a single-atom dopant on the optoelectronic and chemical properties. Nanoscale 2017, 9, 9529– 9536, DOI: 10.1039/C7NR02844JGoogle Scholar973https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXps1ensro%253D&md5=67fae01d8975685144d9c8e99e75a6e1Direct versus ligand-exchange synthesis of [PtAg28(BDT)12(TPP)4]4- nanoclusters: effect of a single-atom dopant on the optoelectronic and chemical propertiesBootharaju, Megalamane S.; Kozlov, Sergey M.; Cao, Zhen; Harb, Moussab; Parida, Manas R.; Hedhili, Mohamed N.; Mohammed, Omar F.; Bakr, Osman M.; Cavallo, Luigi; Basset, Jean-MarieNanoscale (2017), 9 (27), 9529-9536CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Heteroatom doping of atomically precise nanoclusters (NCs) often yields a mixt. of doped and undoped products of single-atom difference, whose sepn. is extremely difficult. To overcome this challenge, novel synthesis methods are required to offer monodisperse doped NCs. For instance, the direct synthesis of PtAg28 NCs produces a mixt. of [Ag29(BDT)12(TPP)4]3- and [PtAg28(BDT)12(TPP)4]4- NCs (TPP: triphenylphosphine; BDT: 1,3-benzenedithiolate). Here, we designed a ligand-exchange (LE) strategy to synthesize single-sized, Pt-doped, superat. Ag NCs [PtAg28(BDT)12(TPP)4]4- by LE of [Pt2Ag23Cl7(TPP)10] NCs with BDTH2 (1,3-benzenedithiol). The doped NCs were thoroughly characterized by optical and photoelectron spectroscopy, mass spectrometry, total electron count, and time-dependent d. functional theory (TDDFT). We show that the Pt dopant occupies the center of the PtAg28 cluster, modulates its electronic structure and enhances its photoluminescence intensity and excited-state lifetime, and also enables solvent interactions with the NC surface. Furthermore, doped NCs showed unique reactivity with metal ions - the central Pt atom of PtAg28 could not be replaced by Au, unlike the central Ag of Ag29 NCs. The achieved synthesis of single-sized PtAg28 clusters will facilitate further applications of the LE strategy for the exploration of novel multimetallic NCs.
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974Li, Q.; Lambright, K. J.; Taylor, M. G.; Kirschbaum, K.; Luo, T.-Y.; Zhao, J.; Mpourmpakis, G.; Mokashi-Punekar, S.; Rosi, N. L.; Jin, R. Reconstructing the surface of gold nanoclusters by cadmium doping. J. Am. Chem. Soc. 2017, 139, 17779– 17782, DOI: 10.1021/jacs.7b11491Google Scholar974https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVOit73P&md5=f91b82d39020d45a6eeec0caa113ae0bReconstructing surface of gold nanoclusters by cadmium dopingLi, Qi; Lambright, Kelly J.; Taylor, Michael G.; Kirschbaum, Kristin; Luo, Tian-Yi; Zhao, Jianbo; Mpourmpakis, Giannis; Mokashi-Punekar, Soumitra; Rosi, Nathaniel L.; Jin, RongchaoJournal of the American Chemical Society (2017), 139 (49), 17779-17782CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Atomically precise metal nanoclusters with tailored surface structures are important for both fundamental studies and practical applications. The development of new methods for tailoring the surface structure in a controllable manner has long been sought. In this work, we report surface reconstruction induced by cadmium doping into the [Au23(SR)16]- (R = cyclohexyl) nanocluster, in which two neighboring surface Au at. sites "coalesce" into one Cd at. site and, accordingly, a new bimetal nanocluster, [Au19Cd2(SR)16]-, is produced. Interestingly, a Cd(S-Au-S)3 "paw-like" surface motif is obsd. for the first time in nanocluster structures. In such a motif, the Cd atom acts as a junction which connects three monomeric -S-Au-S- motifs. D. functional theory calcns. are performed to understand the two unique Cd locations. Furthermore, we demonstrate different doping modes when the [Au23(SR)16]- nanocluster is doped with different metals (Cu, Ag), including (i) simple substitution and (ii) total structure transformation, as opposed to surface reconstruction for Cd doping. This work greatly expands doping chem. for tailoring the structures of nanoclusters and is expected to open new avenues for designing nanoclusters with novel surface structures using different dopants.
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975Liao, L.; Zhou, S.; Dai, Y.; Liu, L.; Yao, C.; Fu, C.; Yang, J.; Wu, Z. Mono-mercury doping of Au25 and the HOMO/LUMO energies evaluation employing differential pulse voltammetry. J. Am. Chem. Soc. 2015, 137, 9511– 9514, DOI: 10.1021/jacs.5b03483Google Scholar975https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtF2ltrrE&md5=f13e2e8eb1f42c7f7fb583dd9cfa8410Mono-Mercury Doping of Au25 and the HOMO/LUMO Energies Evaluation Employing Differential Pulse VoltammetryLiao, Lingwen; Zhou, Shiming; Dai, Yafei; Liu, Liren; Yao, Chuanhao; Fu, Cenfeng; Yang, Jinlong; Wu, ZhikunJournal of the American Chemical Society (2015), 137 (30), 9511-9514CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Controlling the bimetal nanoparticle with at. monodispersity is still challenging. Herein, a monodisperse bimetal nanoparticle was synthesized in 25% yield (on gold atom basis) by an unusual replacement method. The formula of the nanoparticle is Au24Hg1(PET)18 (PET: phenylethanethiolate) by high-resoln. ESI-MS spectrometry in conjunction with multiple analyses including XPS and TGA. X-ray single-crystal diffraction reveals that the structure of Au24Hg1(PET)18 remains the structural framework of Au25(PET)18 with one of the outer-shell gold atoms replaced by one Hg atom, which is further supported by theor. calcns. and exptl. results as well. Importantly, differential pulse voltammetry (DPV) is 1st employed to est. the highest occupied mol. orbit (HOMO) and the lowest unoccupied mol. orbit (LUMO) energies of Au24Hg1(PET)18 based on previous calcns.
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976Yao, C.; Lin, Y.-j.; Yuan, J.; Liao, L.; Zhu, M.; Weng, L.-h.; Yang, J.; Wu, Z. Mono-cadmium vs mono-mercury doping of Au25 nanoclusters. J. Am. Chem. Soc. 2015, 137, 15350– 15353, DOI: 10.1021/jacs.5b09627Google Scholar976https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFSmtb7F&md5=2cfde4145db071971db70f1ddfe93d5fMono-cadmium vs Mono-mercury Doping of Au25 NanoclustersYao, Chuanhao; Lin, Yue-jian; Yuan, Jinyun; Liao, Lingwen; Zhu, Min; Weng, Lin-hong; Yang, Jinlong; Wu, ZhikunJournal of the American Chemical Society (2015), 137 (49), 15350-15353CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Controlling the dopant type, no., and position in doped metal nanoclusters (nanoparticles) is crucial but challenging. In the work described herein, the authors successfully achieved the mono-cadmium doping of Au25 nanoclusters, and revealed using x-ray crystallog. (of [Au24Cd(SCH2CH2Ph)18]·2C7H8) in combination with theor. calcns. that one of the inner-shell gold atoms of Au25 was replaced by a Cd atom. The doping mode is distinctly different from that of mono-mercury doping, where one of the outer-shell Au atoms was replaced by a Hg atom. Au24Cd is readily transformed to Au24Hg, while the reverse (transformation from Au24Hg to Au24Cd) is forbidden under the investigated conditions.
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977Wang, Y.; Liu, Y.-H.; Zhang, Y.; Wang, F.; Kowalski, P. J.; Rohrs, H. W.; Loomis, R. A.; Gross, M. L.; Buhro, W. E. Isolation of the Magic-Size CdSe Nanoclusters [(CdSe)13(n-octylamine)13] and [(CdSe)13(oleylamine)13]. Angew. Chem., Int. Ed. 2012, 51, 6154– 6157, DOI: 10.1002/anie.201202380Google Scholar977https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XmvVCjsrk%253D&md5=4f53bfc77613289f37a489f5bc8328cfIsolation of the Magic-Size CdSe Nanoclusters [(CdSe)13(n-octylamine)13] and [(CdSe)13(oleylamine)13]Wang, Yuanyuan; Liu, Yi-Hsin; Zhang, Ying; Wang, Fudong; Kowalski, Paul J.; Rohrs, Henry W.; Loomis, Richard A.; Gross, Michael L.; Buhro, William E.Angewandte Chemie, International Edition (2012), 51 (25), 6154-6157, S6154/1-S6154/15CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)(CdSe)13 nanoclusters have been recently reported as intermediates in the synthesis of CdSe quantum belts (nano-ribbons). A lamellar intermediate phase collected from the quantum-belt synthesis is [(CdSe)13(M-OCtylamine)13], the smallest, discrete, magic-size nanocluster of CdSe that has been obsd. Free, sol. [(CdSe)13(Oleylamine)13] nanoclusters are released from the insol. [(CdSe)13(n-octylamine)13] upon ligand exchange. Nanoclusters of (CdSe)13 are generated by reaction of cadmium acetate dihydrate, [Cd(OAc)2(H2O)2], with selenourea [H2NC(Se)NH2] in n-octylamine solvent at room temp. Combination of CdX2 compds. (X = halide,'1'13' OAc'1') with n-octylamine results in the spontaneous formation of lamellar mesophases consisting of CdX2 layers sepd. by n-octylamine bilayers. Addn. of selenourea generates a mixt. of CdSe nanoclusters that converts completely into (CdSe)13,. A white ppt. is deposited, which we now show to be [(CdSe)13(/i-octylamine)13].
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978Liu, Y. H.; Wang, F.; Wang, Y.; Gibbons, P. C.; Buhro, W. E. Lamellar assembly of cadmium selenide nanoclusters into quantum belts. J. Am. Chem. Soc. 2011, 133, 17005– 17013, DOI: 10.1021/ja206776gGoogle Scholar978https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1ClsbvP&md5=af6c47a939df2bfba4e688c2b3438cc2Lamellar Assembly of Cadmium Selenide Nanoclusters into Quantum BeltsLiu, Yi-Hsin; Wang, Fudong; Wang, Yuanyuan; Gibbons, Patrick C.; Buhro, William E.Journal of the American Chemical Society (2011), 133 (42), 17005-17013CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Here, we elucidate a double-lamellar-template pathway for the formation of CdSe quantum belts. The lamellar templates form initially by dissoln. of the CdX2 precursors in the n-octylamine solvent. Exposure of the precursor templates to selenourea at room temp. ultimately affords (CdSe)13 nanoclusters entrained within the double-lamellar templates. Upon heating, the nanoclusters are transformed to CdSe quantum belts having widths, lengths, and thicknesses that are predetd. by the dimensions within the templates. This template synthesis is responsible for the excellent optical properties exhibited by the quantum belts. We propose that the templated-growth pathway is responsible for the formation of the various flat, colloidal nanocrystals recently discovered, including nanoribbons, nanoplatelets, nanosheets, and nanodisks.
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979Hsieh, T.-E.; Yang, T.-W.; Hsieh, C.-Y.; Huang, S.-J.; Yeh, Y.-Q.; Chen, C.-H.; Li, E. Y.; Liu, Y.-H. Unraveling the structure of magic-size (CdSe)13 cluster pairs. Chem. Mater. 2018, 30, 5468– 5477, DOI: 10.1021/acs.chemmater.8b02468Google Scholar979https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtlCnsbbM&md5=af47530237d2cf870922909732f24d86Unraveling the Structure of Magic-Size (CdSe)13 Cluster PairsHsieh, Tzung-En; Yang, Ta-Wei; Hsieh, Cheng-Yin; Huang, Shing-Jong; Yeh, Yi-Qi; Chen, Ching-Hsiang; Li, Elise Y.; Liu, Yi-HsinChemistry of Materials (2018), 30 (15), 5468-5477CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)Cadmium selenide is a II-VI semiconductor model system known for its nanoparticle prepn., growth mechanism, luminescence properties, and quantum confinement studies. For the past 2 decades, various thermodynamically stable "magic-size nanoclusters (MSCs)" of CdSe have been obsd., isolated, and theor. calcd. Nevertheless, none of the proposed structures were exptl. confirmed due to the small crystal domains beyond the diffraction limit. With a combination of nondestructive SAXS, WAXS, XRD, XPS, EXAFS, and MAS NMR techniques, we were able to verify the phase transformation, shape, size dimension, local bonding, and chem. environments of (CdSe)13 nanoclusters, which are indicative of a paired cluster model. These exptl. results are consistent with the size, shape, bond lengths, dipole moment, and charge densities of the proposed "paired-tubular geometry" predicted by computational approaches. In this article, we revisit the formation pathway of the mysterious (CdSe)13 nanoclusters and propose a paired cluster structure model for better understanding of II-VI semiconductor nanoclusters.
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980Yu, J. H.; Liu, X.; Kweon, K. E.; Joo, J.; Park, J.; Ko, K.-T.; Lee, D. W.; Shen, S.; Tivakornsasithorn, K.; Son, J. S. Giant Zeeman splitting in nucleation-controlled doped CdSe:Mn2+ quantum nanoribbons. Nat. Mater. 2010, 9, 47– 53, DOI: 10.1038/nmat2572Google Scholar980https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFOnsrrF&md5=e4c63402a3665377e1e141b4bd302229Giant Zeeman splitting in nucleation-controlled doped CdSe:Mn2+ quantum nanoribbonsYu, Jung Ho; Liu, Xinyu; Kweon, Kyoung Eun; Joo, Jin; Park, Jiwon; Ko, Kyung-Tae; Lee, Dong Won; Shen, Shaoping; Tivakornsasithorn, Kritsanu; Son, Jae Sung; Park, Jae-Hoon; Kim, Young-Woon; Hwang, Gyeong S.; Dobrowolska, Margaret; Furdyna, Jacek K.; Hyeon, TaeghwanNature Materials (2010), 9 (1), 47-53CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Doping of semiconductor nanocrystals by transition-metal ions has attracted tremendous attention owing to their nanoscale spintronic applications. Such doping is, however, difficult to achieve in low-dimensional strongly quantum confined nanostructures by conventional growth procedures. The incorporation of manganese ions up to 10% into CdSe quantum nanoribbons can be readily achieved by a nucleation-controlled doping process. The cation-exchange reaction of (CdSe)13 clusters with Mn2+ ions governs the Mn2+ incorporation during the nucleation stage. This highly efficient Mn2+ doping of the CdSe quantum nanoribbons results in giant exciton Zeeman splitting with an effective g-factor of ∼600, the largest value seen so far in dild. magnetic semiconductor nanocrystals. Also, the sign of the s-d exchange is inverted to neg. owing to the exceptionally strong quantum confinement in the authors' nanoribbons. The nucleation-controlled doping strategy demonstrated here thus opens the possibility of doping various strongly quantum confined nanocrystals for diverse applications.
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981Yang, J.; Fainblat, R.; Kwon, S. G.; Muckel, F.; Yu, J. H.; Terlinden, H.; Kim, B. H.; Iavarone, D.; Choi, M. K.; Kim, I. Y. Route to the smallest doped semiconductor: Mn2+-doped (CdSe)13 clusters. J. Am. Chem. Soc. 2015, 137, 12776– 12779, DOI: 10.1021/jacs.5b07888Google Scholar981https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1ajsb7O&md5=46556fbec1ac8be691dfa5bda43cbb6aRoute to the Smallest Doped Semiconductor: Mn2+-Doped (CdSe)13 ClustersYang, Jiwoong; Fainblat, Rachel; Kwon, Soon Gu; Muckel, Franziska; Yu, Jung Ho; Terlinden, Hendrik; Kim, Byung Hyo; Iavarone, Dino; Choi, Moon Kee; Kim, In Young; Park, Inchul; Hong, Hyo-Ki; Lee, Jihwa; Son, Jae Sung; Lee, Zonghoon; Kang, Kisuk; Hwang, Seong-Ju; Bacher, Gerd; Hyeon, TaeghwanJournal of the American Chemical Society (2015), 137 (40), 12776-12779CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Doping semiconductor nanocrystals with magnetic transition-metal ions has attracted fundamental interest to obtain a nanoscale dil. magnetic semiconductor, which has unique spin exchange interaction between magnetic spin and exciton. So far, the study on the doped semiconductor NCs has usually been conducted with NCs with larger than 2 nm because of synthetic challenges. Herein, we report the synthesis and characterization of Mn2+-doped (CdSe)13 clusters, the smallest doped semiconductors. In this study, single-sized doped clusters are produced in large scale. Despite their small size, these clusters have semiconductor band structure instead of that of mols. Surprisingly, the clusters show multiple excitonic transitions with different magneto-optical activities, which can be attributed to the fine structure splitting. Magneto-optically active states exhibit giant Zeeman splittings up to elevated temps. (128 K) with large g-factors of 81(±8) at 4 K. Our results present a new synthetic method for doped clusters and facilitate the understanding of doped semiconductor at the boundary of mols. and quantum nanostructure.
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982Muckel, F.; Yang, J.; Lorenz, S.; Baek, W.; Chang, H.; Hyeon, T.; Bacher, G.; Fainblat, R. Digital doping in magic-sized CdSe clusters. ACS Nano 2016, 10, 7135– 7141, DOI: 10.1021/acsnano.6b03348Google Scholar982https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFKrsL%252FF&md5=7589e98e346f78bb92875ec65085bc04Digital Doping in Magic-Sized CdSe ClustersMuckel, Franziska; Yang, Jiwoong; Lorenz, Severin; Baek, Woonhyuk; Chang, Hogeun; Hyeon, Taeghwan; Bacher, Gerd; Fainblat, RachelACS Nano (2016), 10 (7), 7135-7141CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Magic-sized semiconductor clusters represent an exciting class of materials located at the boundary between quantum dots and mols. It is expected that replacing single atoms of the host crystal with individual dopants in a 1-by-one fashion can lead to unique modifications of the material properties. Here, the authors demonstrate the dependence of the magneto-optical response of (CdSe)13 clusters on the discrete no. of Mn2+ ion dopants. Using time-of-flight mass spectrometry, the authors are able to distinguish undoped, monodoped, and bidoped cluster species, allowing for an extn. of the relative amt. of each species for a specific av. doping concn. A giant magneto-optical response is obsd. up to room temp. with clear evidence that exclusively monodoped clusters are magneto-optically active, whereas the Mn2+ ions in bidoped clusters couple antiferromagnetically and are magneto-optically passive. Mn2+-doped clusters therefore represent a system where magneto-optical functionality is caused by solitary dopants, which might be beneficial for future solotronic applications.
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983Palencia, C.; Yu, K.; Boldt, K. The future of colloidal semiconductor magic-size clusters. ACS Nano 2020, 14, 1227– 1235, DOI: 10.1021/acsnano.0c00040Google Scholar983https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhvFegs70%253D&md5=9b81d754f839c9d8be278d473855fc9bThe Future of Colloidal Semiconductor Magic-Size ClustersPalencia, Cristina; Yu, Kui; Boldt, KlausACS Nano (2020), 14 (2), 1227-1235CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. Atomically defined, zero-dimensional magic-size clusters play pivotal roles in the nucleation and growth of semiconductor nanocrystals. Thus, they provide new opportunities to understand and to control nucleation and growth reactions beyond classical nucleation theory and to employ these reactions in the colloidal synthesis of increasingly complex and anisotropic nanomaterials with at. level monodispersity. Both challenges require reliable detn. of the exact structure and size of these ultrasmall and metastable nanoclusters. In this Perspective, we review and discuss the current challenges in analytics of magic-size clusters, in elucidating their formation mechanism, and in using them as next-generation reagents in colloidal chem.
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984Lebon, A.; Aguado, A.; Vega, A. A new magnetic superatom:. Phys. Chem. Chem. Phys. 2015, 17, 28033– 28043, DOI: 10.1039/C4CP03753GGoogle Scholar984https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhslOisLzI&md5=1b28f3009f79d4b2f9ea7ba65ee3400eA new magnetic superatom: Cr@Zn17Lebon, Alexandre; Aguado, Andres; Vega, AndresPhysical Chemistry Chemical Physics (2015), 17 (42), 28033-28043CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We demonstrate, by means of fully unconstrained d. functional theory calcns., that cluster Zn17 endohedrally doped with a Cr impurity can be qualified as a magnetic superalkali cluster. We explain the origin of its high stability, its low vertical ionization potential and its high total spin magnetic moment which amts. to 6 μB, exactly the same value as that of the isolated Cr atom. With the aim of exploring the possibility of designing a bistable magnetic nanoparticle, with a corresponding inter-unit exchange coupling, we also consider the assembling of two such units through different contact regions and in different magnetic configurations. Furthermore, we analyze up to which extent is the Zn shell able to preserve the electronic properties of the embedded Cr atom, both against coalescence of the two superatoms forming the magnetically bistable nanoparticle, and upon the adsorption of an O2 mol. or even under an oversatd. O2 atmosphere. Our results are discussed not only emphasizing the fundamental phys. and chem. aspects, but also with an eye on the new prospects that those Cr@Zn17 magnetic superalkali clusters (and others of similar kind) may open in spintronics-, mol. electronics- or biomedical-applications.
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985Kumar, V. High symmetry Nbn and Tan (n = 12, 15, and 17) clusters: High magnetic moments and the finding of superatoms with doping. Comput. Theor. Chem. 2013, 1021, 149– 154, DOI: 10.1016/j.comptc.2013.07.003Google Scholar985https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVWqs7%252FO&md5=3cbeb0a1792329d2d8c34c7e411d1878High symmetry Nbn and Tan (n = 12, 15, and 17) clusters: High magnetic moments and the finding of superatoms with dopingKumar, VijayComputational & Theoretical Chemistry (2013), 1021 (), 149-154CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)Using ab initio calcns., we study Nbn and Tan clusters with n = 12, 15, and 17 and find superatoms made of transition metals. Nb12 and Ta12 have an empty cage icosahedral structure. Neutral Ta12 has icosahedral symmetry and 2 μB magnetic moments while the cage for Nb12 is slightly distorted and has no magnetic moment. These clusters behave like a divalent superatom. Accordingly an oxygen atom interacts exohedrally on a 3-fold site of the icosahedral cage like an MgO mol. and leaves the cage intact while Fe, Ru, and Os atoms can be endohedrally doped in Ta12 to produce electronically closed shell clusters with large highest occupied-LUMO (HOMO-LUMO) gap. Also isoelectronic Co@X12 and Rh@X12 (X = Nb and Ta) cations have a large HOMO-LUMO gap of up to about 1 eV. In these cases the magnetic moment is quenched. On the other hand doping with Ni leaves the magnetic behavior of Ta12 the same. Further anions of Nb15 and Ta15 have a closed electronic shell structure and a singlet ground state with a large HOMO-LUMO gap. We show that isoelectronic Nb14Mo, Nb14W, Ta14Mo, Ta14W, Nb14Mn+, Nb14Re+, Ta14Mn+, and Ta14Re+ all have a large HOMO-LUMO gap of up to about 1.0 eV and are magic clusters. Most interestingly Ta17 has a tetrahedrally sym. Z16 Frank-Kasper polyhedral structure with a large magnetic moment of 5 μB. On the other hand the magnetic moment on Nb17 cluster is 1 μB. The magnetic moment on Ta17 is surprisingly large and it is counter intuitive as normally the magnetic moments decrease as one goes down in a column in the periodic table but some tantalum clusters behave differently. Doping of the n = 17 clusters with Zr at the center leaves Zr@Ta16 magnetic with 2 μB and 6 μB magnetic moments nearly degenerate while Zr@Nb16 has zero magnetic moment.
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This article references 985 other publications.
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1De Heer, W. A. The physics of simple metal clusters: experimental aspects and simple models. Rev. Mod. Phys. 1993, 65, 611– 676, DOI: 10.1103/RevModPhys.65.6111https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsVCgu70%253D&md5=ba77ebdb31643f78f19a6183aa62c3deThe physics of simple metal clusters: experimental aspects and simple modelsde Heer, Walt A.Reviews of Modern Physics (1993), 65 (3, Pt. 1), 611-76CODEN: RMPHAT; ISSN:0034-6861.A review with many refs. The study of simple metal clusters has burgeoned in the last decade, motivated by the growing interest in the evolution of phys. properties from the atom to the bulk solid, a progression passing through the domain of at. clusters. On the exptl. side, the rapid development of new techniques for producing the clusters and for probing and detecting them has resulted in a phenomenal increase in the knowledge of these systems. For clusters of the simplest metals (the alkali and noble metals), the electronic structure is dominated by the no. of valence electrons, and the ionic cores are of secondary importance. These electrons are delocalized, and the electronic system exhibits a shell structure that is closely related to the well-known nuclear shell structure. The results from a broad range of expts. are compared with theory. The properties discussed include: behavior of the mass-abundance spectra; polarizabilities; ionization potentials; photoelectron spectra; optical spectra; and fragmentation phenomena.
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2Castleman, A.; Bowen, K. Clusters: Structure, energetics, and dynamics of intermediate states of matter. J. Phys. Chem. 1996, 100, 12911– 12944, DOI: 10.1021/jp961030k2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xkt1altb0%253D&md5=5d7da2f1be8addb21abe4a461a51e78eClusters: Structure, Energetics, and Dynamics of Intermediate States of MatterCastleman, A. W., Jr.; Bowen, K. H., Jr.Journal of Physical Chemistry (1996), 100 (31), 12911-12944CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)A review with 692 refs.; the field of cluster research can trace its origins back to the mid-nineteenth century when early studies of colloids, aerosols, and nucleation phenomena were reported. The field underwent a resurgence of interest several decades ago when well-defined clusters were obsd. in supersonic expansions that could be investigated using mass spectrometers. The advent of the laser provided a new dimension, enabling detailed spectroscopic observations through the probing of systems of varying size and degree of solvation. Modern interest derives from recognition that interrogating clusters provides a way of studying the energetics and dynamics of intermediate states of matter as cluster systems evolve from the gas toward the condensed state. Herein, we endeavor to highlight some of the significant advances which have been made during the past several decades that have led to a nearly explosive growth of interest in the field of cluster science. Finally, we conclude that the field will continue to expand through interests in basic phenomena, as well as through numerous applications of cluster research to fields ranging from catalysis to the quest for new cluster-assembled materials.
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3Alonso, J. Electronic and atomic structure, and magnetism of transition-metal clusters. Chem. Rev. 2000, 100, 637– 678, DOI: 10.1021/cr980391o3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXksFyhug%253D%253D&md5=b6242dac72711b7f9674c54bd5899d08Electronic and Atomic Structure, and Magnetism of Transition-Metal ClustersAlonso, J. A.Chemical Reviews (Washington, D. C.) (2000), 100 (2), 637-677CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review is presented with 291 refs. with discussion on noble metal clusters, general bonding properties and electronic structure of clusters of transition metals, thermionic emission from refractory metal clusters, nonmetal-metal transition, icosahedral model of Ni clusters and its relation to reactivity, size and temp. dependence of magnetic moments and their measurement, magnetic shell models, DFT study of magnetic properties of clusters of 3d elements, magnetism in clusters of 4d elements, noncollinear magnetism in iron clusters.
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4Janssens, E.; Neukermans, S.; Lievens, P. Shells of electrons in metal doped simple metal clusters. Curr. Opin. Solid State Mater. Sci. 2004, 8, 185– 193, DOI: 10.1016/j.cossms.2004.09.0024https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtlSrsLc%253D&md5=e11690246370b01b65e94b5c77b80ae8Shells of electrons in metal doped simple metal clustersJanssens, Ewald; Neukermans, Sven; Lievens, PeterCurrent Opinion in Solid State & Materials Science (2005), 8 (3-4), 185-193CODEN: COSSFX; ISSN:1359-0286. (Elsevier Ltd.)A review. Recent studies of electronic and structural properties of small doped metal clusters are reviewed. Both theor. and exptl. investigations of size and compn. dependent cluster properties have emphasized the importance of the interplay between geometry and electronic structure. The conceptually simple phenomenol. shell models, which have been used extensively to describe bare simple metal clusters, are extended towards different types of doped cluster species by choosing appropriate ad hoc potentials. More detailed fundamental understanding is gained by investigating the delocalized MOs as computed with ab initio d. functional theory.
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5Baletto, F.; Ferrando, R. Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effects. Rev. Mod. Phys. 2005, 77, 371– 423, DOI: 10.1103/RevModPhys.77.3715https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXkvVCmtL0%253D&md5=f0c919972406ca61cf22e8dc64b3dec3Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effectsBaletto, Francesca; Ferrando, RiccardoReviews of Modern Physics (2005), 77 (1), 371-423CODEN: RMPHAT; ISSN:0034-6861. (American Physical Society)A review. The structural properties of free nanoclusters are reviewed. Special attention is paid to the interplay of energetic, thermodn., and kinetic factors in the explanation of cluster structures that are actually obsd. in expts. The review starts with a brief summary of the exptl. methods for the prodn. of free nanoclusters and then considers theor. and simulation issues, always discussed in close connection with the exptl. results. The energetic properties are treated first, along with methods for modeling elementary constituent interactions and for global optimization on the cluster potential-energy surface. After that, a section on cluster thermodn. follows. The discussion includes the anal. of solid-solid structural transitions and of melting, with its size dependence. The last section is devoted to the growth kinetics of free nanoclusters and treats the growth of isolated clusters and their coalescence. Several specific systems are analyzed.
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6Ferrando, R.; Jellinek, J.; Johnston, R. L. Nanoalloys: from theory to applications of alloy clusters and nanoparticles. Chem. Rev. 2008, 108, 845– 910, DOI: 10.1021/cr040090g6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtVCkt7w%253D&md5=58cba8c4e8af59b6e765a54be5bb1926Nanoalloys: From Theory to Applications of Alloy Clusters and NanoparticlesFerrando, Riccardo; Jellinek, Julius; Johnston, Roy L.Chemical Reviews (Washington, DC, United States) (2008), 108 (3), 845-910CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The topics discussed are: types and structures of nanoalloys (NA), their application, methods for generating NA, exptl. techniques for characterization and modeling potential energy surface of NA. Further topics include: structural optical, and magnetic properties, catalysis of NA, melting, intermixing kinetics, freezing, growth, and coalescence of NA, ternary NA clusters.
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7Jena, P.; Castleman, A., Jr Mass spectrometry and its role in advancing cluster science. Int. J. Mass Spectrom. 2015, 377, 235– 247, DOI: 10.1016/j.ijms.2014.08.0337https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVCju73K&md5=9f48dcdcde71c606e100c8cde57c4a12Mass spectrometry and its role in advancing cluster scienceJena, P.; Castleman, A. W.International Journal of Mass Spectrometry (2015), 377 (), 235-247CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)Clusters composed of a few to a few hundred atoms are the ultimate nanoparticles where every atom and every electron count. Over the past 50 years clusters have evolved as a new field of matter intermediate between atoms and bulk. In this retrospective we trace the role mass spectrometry has played in this emerging field with emphasis on how extremely intense mass peaks indicating a high abundance of clusters led to the discovery of magic nos. in alkali metal clusters, the fullerenes in carbon clusters, and "Met-Cars" in transition-metal carbide clusters. Magic nos. in alkali metal clusters in turn helped bridge the gap between two disparate fields, at. physics and nuclear physics. Studies of mass spectra combined with theory and a variety of other exptl. techniques have since led to a fundamental understanding of the structure-property relationships of clusters, thus broadening the scope of cluster science. Clusters not only serve as a bridge between atoms and bulk and between at. and nuclear physics, but also as a bridge across many disciplines. Although this retrospective is focused on at. clusters, briefly discussed is the solvation phenomenon, a subject to which mass spectrometry has and continues to make a large contribution.
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8Zhao, J.; Huang, X.; Jin, P.; Chen, Z. Magnetic properties of atomic clusters and endohedral metallofullerenes. Coord. Chem. Rev. 2015, 289, 315– 340, DOI: 10.1016/j.ccr.2014.12.0138https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmvF2lsA%253D%253D&md5=76e70bc6b019cea2517546b26fc74b89Magnetic properties of atomic clusters and endohedral metallofullerenesZhao, Jijun; Huang, Xiaoming; Jin, Peng; Chen, ZhongfangCoordination Chemistry Reviews (2015), 289-290 (), 315-340CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)Magnetic clusters are aggregates of a few to thousands of atoms or mols. that exhibit magnetism. Understanding the evolution of magnetism from individual atom to bulk solid is fundamentally important, and combining different types and no. of atoms would lead to many opportunities in tuning magnetic properties of an alloy cluster. The magnetic behaviors of a cluster can be measured by the Stern-Gerlach deflections or the X-ray magnetic CD spectroscopy in a mol. beam and calcd. by ab initio methods. Herein we present a comprehensive review on the exptl. and theor. progresses on the magnetic properties of the ligand-free gas-phase clusters up to a few hundred atoms, including elemental metal clusters, alloy clusters, metal-doped semiconductor clusters, magnetic superatom clusters. Endohedral metallofullerenes, a special kind of magnetic clusters, are also briefly illustrated.
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9Luo, Z.; Castleman, A., Jr; Khanna, S. N. Reactivity of metal clusters. Chem. Rev. 2016, 116, 14456– 14492, DOI: 10.1021/acs.chemrev.6b002309https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFelu7nE&md5=7f53c625aea3fd14116584bf25c08ca8Reactivity of Metal ClustersLuo, Zhixun; Castleman, A. W.; Khanna, Shiv N.Chemical Reviews (Washington, DC, United States) (2016), 116 (23), 14456-14492CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)We summarize here the research advances on the reactivity of metal clusters. After a simple introduction of apparatuses used for gas-phase cluster reactions, we focus on the reactivity of metal clusters with various polar and nonpolar mols. in the gas phase and illustrate how elementary reactions of metal clusters proceed one-step at a time under a combination of geometric and electronic reorganization. The topics discussed in this study include chem. adsorption, addn. reaction, cleavage of chem. bonds, etching effect, spin effect, the harpoon mechanism, and the complementary active sites (CAS) mechanism, among others. Insights into the reactivity of metal clusters not only facilitate a better understanding of the fundamentals in condensed-phase chem. but also provide a way to dissect the stability and reactivity of monolayer-protected clusters synthesized via wet chem.
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10Claridge, S. A.; Castleman, A., Jr; Khanna, S. N.; Murray, C. B.; Sen, A.; Weiss, P. S. Cluster-assembled materials. ACS Nano 2009, 3, 244– 255, DOI: 10.1021/nn800820e10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVyksrk%253D&md5=92e6025e94ae3884c8ca7a098859acabCluster-Assembled MaterialsClaridge, Shelley A.; Castleman, A. W., Jr.; Khanna, Shiv N.; Murray, Christopher B.; Sen, Ayusman; Weiss, Paul S.ACS Nano (2009), 3 (2), 244-255CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. Cluster-assembled materials offer the ability to tune component properties, lattice parameters, and thus coupling of phys. properties through the careful selection and assembly of building blocks. Multi-atom clusters have been found to exhibit phys. properties beyond those available from the std. elements in the periodic table; classification of the properties of such clusters effectively enables expansion of the periodic table to a third dimension. Using clusters as superat. building blocks for hierarchically assembled materials allows these properties to be incorporated into designer materials with tailored properties. Cluster-assembled materials are currently being explored and methods developed to control their design and function. Here, we discuss examples of building block syntheses, assembly strategies, and property control achieved to date.
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11Mandal, S.; Reber, A. C.; Qian, M.; Weiss, P. S.; Khanna, S. N.; Sen, A. Controlling the band gap energy of cluster-assembled materials. Acc. Chem. Res. 2013, 46, 2385– 2395, DOI: 10.1021/ar300297511https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXosFygsb0%253D&md5=515458133c6780a86848eff3b34768b1Controlling the Band Gap Energy of Cluster-Assembled MaterialsMandal, Sukhendu; Reber, Arthur C.; Qian, Meichun; Weiss, Paul S.; Khanna, Shiv N.; Sen, AyusmanAccounts of Chemical Research (2013), 46 (11), 2385-2395CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. Cluster-assembled materials combine the nanoscale size and compn.-dependent properties of clusters, which have highly tunable magnetic and electronic properties useful for a great variety of potential technologies. To understand the emergent properties as clusters are assembled into hierarchical materials, the authors synthesized 23 cluster-assembled materials composed of As73--based motifs and different countercations and measured their band gap energies. The band gap energy varies from 1.09 to 2.21 eV. The authors have carried out 1st principles electronic structure studies to identify the phys. mechanisms that enable control of the band gap edges of the cluster assemblies. The choice of counterion has a profound effect on the band gap energy in ionic clusterassemblies. The top of the valence band is localized on the arsenic cluster, while the conduction band edge is located on the alkali metal counterions. Changing the counterion changes the position of the conduction band edge, enabling control of the band gap energy. The authors can also vary the architecture of the ionic solid by incorporating cryptates as counterions, which provide charge but are sepd. from the clusters by bulky ligands. Higher dimensionality typically decreases the band gap energy through band broadening; however band gap energies increased upon moving from zero-dimensional (0D) to two-dimensional (2D) assemblies. This is because internal elec. fields generated by the counterion preferentially stabilize the adjacent lone pair orbitals that mark the top of the valence band. Thus, the choice of the counterion can control the position of the conduction band edge of ionic cluster assemblies. The dimensionality of the solid via internal elec. fields can control the valence band edge. Through covalently linking arsenic clusters into composite building blocks, the authors also were able to tune the band gap energy. The authors used a theor. description based on cluster orbital theory to provide microscopic understanding of the electronic character of the composite building blocks and the obsd. variations in the band gap energy. Also, dimeric linkers can be used to control the band gap energy. Lastly, the authors also studied the effects of charge transfer complexes of M(CO)3 on the band gap energy.
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12Jena, P.; Sun, Q. Super atomic clusters: design rules and potential for building blocks of materials. Chem. Rev. 2018, 118, 5755– 5870, DOI: 10.1021/acs.chemrev.7b0052412https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtVWku7vO&md5=b77bee290200e431d0d7af487cb3d596Super Atomic Clusters: Design Rules and Potential for Building Blocks of MaterialsJena, Puru; Sun, QiangChemical Reviews (Washington, DC, United States) (2018), 118 (11), 5755-5870CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)Atomic clusters, consisting of a few to a few thousand atoms, have emerged over the past 40 years as the ultimate nanoparticles, whose structure and properties can be controlled one atom at a time. One of the early motivations in studying clusters was to understand how the properties of matter evolve as a function of size, shape, and compn. Over the past few decades, more than 200,000 papers have been published in this field. These studies have not only led to a considerable understanding of this evolution from clusters to crystals, but also have revealed many unusual size-specific properties that make cluster science an interdisciplinary field on its own, bridging physics, chem., materials science, biol., and medicine. More importantly, the possibility of creating a new class of materials, composed of clusters instead of atoms as building blocks, has fueled the hope that one can synthesize materials from the bottom-up with unique and tailored properties. This Review focuses on the properties that set clusters apart from their corresponding bulk. Furthermore, this Review describes how different electron-counting rules can lead to the design of stable clusters, mimicking the chem. of atoms. We highlight the potential of these "superatoms" as building blocks of cluster-assembled materials. Specifically, we emphasize cluster-inspired materials for energy applications. The concluding section includes a summary of the salient features of clusters, potential challenges that remain, and an outlook for the future of cluster science.
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13Kumar, V. In Handbook of Nanophysics; CRC Press, 2010; pp 65– 87.There is no corresponding record for this reference.
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14Zhao, J.; Huang, X.; Shi, R.; Tang, L.; Su, Y.; Sai, L. Ab initio global optimization of clusters. Chemical Modelling 2015, 12, 249– 292, DOI: 10.1039/9781782622703-00249There is no corresponding record for this reference.
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15Kumar, V.; Esfarjani, K.; Kawazoe, Y. In Clusters and nanomaterials; Springer, 2002; pp 9– 88.There is no corresponding record for this reference.
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16Knight, W.; Clemenger, K.; de Heer, W. A.; Saunders, W. A.; Chou, M.; Cohen, M. L. Electronic shell structure and abundances of sodium clusters. Phys. Rev. Lett. 1984, 52, 2141– 2143, DOI: 10.1103/PhysRevLett.52.214116https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXktlSltbY%253D&md5=ad028b548afb0a39ba6fb29a7cbb50ddElectronic shell structure and abundances of sodium clustersKnight, W. D.; Clemenger, Keith; De Heer, Walt A.; Saunders, Winston A.; Chou, M. Y.; Cohen, Marvin L.Physical Review Letters (1984), 52 (24), 2141-3CODEN: PRLTAO; ISSN:0031-9007.Mass spectra are presented for Na clusters of N atoms per cluster (N = 4-100) produced in a supersonic expansion with Ar carrier gas. The spectra show large peaks or steps at N = 8, 20, 40, 58, and 92. These can be understood in terms of 1-electron shell model in which independent delocalized at. 3s electrons are bound in a spherically sym. potential well.
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17Frauendorf, S. G.; Guet, C. Atomic clusters as a branch of nuclear physics. Annu. Rev. Nucl. Part. Sci. 2001, 51, 219– 259, DOI: 10.1146/annurev.nucl.51.101701.13235417https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjtVCgsQ%253D%253D&md5=232fece073a366de3d7b29b298bf82ecAtomic clusters as a branch of nuclear physicsFrauendorf, Stefan G.; Guet, ClaudeAnnual Review of Nuclear and Particle Science (2001), 51 (), 219-259CODEN: ARPSDF; ISSN:0163-8998. (Annual Reviews Inc.)The conduction electrons in clusters of simple metal atoms are approximatively independent and free. Nucleons in nuclei also behave as delocalized and independent fermions. This generic behavior generates analogies between metal clusters and nuclei, such as the shell structure, the shapes, and the dipole vibration mode. However, there are also major differences that arise from the presence of ions in metal clusters. Fission of nuclei and clusters, and particle emission from them, reveal these differences.
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18Brack, M. The physics of simple metal clusters: self-consistent jellium model and semiclassical approaches. Rev. Mod. Phys. 1993, 65, 677– 732, DOI: 10.1103/RevModPhys.65.67718https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsVCgu7o%253D&md5=93737e9fadfb0414a790cae69ab2e8f1The physics of simple metal clusters: self-consistent jellium model and semiclassical approachesBrack, MatthiasReviews of Modern Physics (1993), 65 (3, Pt. 1), 677-732CODEN: RMPHAT; ISSN:0034-6861.A review with many refs. The topics discussed include: the hierarchy of theor. approxns. leading to the jellium model; detailed description of the jellium model, including various extensions; the local-d. approxn. to exchange and correlation effects, which greatly simplifies self-consistent calcns. of the electronic structure; the semiclassical approxn. to the single-particle d. matrix, which gives a theor. framework to relate the properties of large clusters to the bulk and macroscopic surface properties; phys. properties (including ground-state binding energies, ionization potentials, and dipole polarizabilities); and treatment of collective electronic excitations from the point of view of cluster response (including some useful sum rules).
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19Itoh, M.; Kumar, V.; Adschiri, T.; Kawazoe, Y. Comprehensive study of sodium, copper, and silver clusters over a wide range of sizes 2 ≤ N ≤ 75. J. Chem. Phys. 2009, 131, 174510, DOI: 10.1063/1.318793419https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtl2hs7nK&md5=f4cabf211f7cb45e3db417eba66444d3Comprehensive study of sodium, copper, and silver clusters over a wide range of sizes 2 ≤ N ≤ 75Itoh, Masahiro; Kumar, Vijay; Adschiri, Tadafumi; Kawazoe, YoshiyukiJournal of Chemical Physics (2009), 131 (17), 174510/1-174510/19CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometric and electronic structures of NaN, CuN, and AgN metal clusters are systematically studied based on the d. functional theory over a wide range of cluster sizes 2 ≤ N ≤ 75. A remarkable similarity is obsd. between the optimized geometric structures of alkali and noble metal clusters over all of the calcd. cluster sizes N. The most stable structures are the same for the three different metal clusters for approx. half the cluster sizes N considered in this study. Even if the most stable structures are different, the same types of structures are obtained when the metastable structures are also considered. For all of the three different metal clusters, the cluster shapes change in the order of linear, planar, opened, and closed structures with increasing N. This structural-type transition leads to a deviation from the monotonic increase in the sp. vol. with N. A remarkable similarity is also obsd. for the N dependence of the cluster energy E(N) for the most stable geometric structures. The amplitude of this energy difference is larger in the two noble metal clusters than in the alkali metal cluster. This is attributed to the contribution of d electrons to the bonds. The magic no. is explicitly defined with a new criterion in the framework of total energy calcns. In the case of NaN, a semiquant. comparison between the exptl. abundance spectra and the total energy calcns. is carried out. The changing aspect of the Kohn-Sham eigenvalues from N = 2 to N = 75 is presented for the three different metal clusters. The feature of the bulk d. of states already appears at N = 75 for all of three clusters. With increasing N, the HOMO-LUMO gap clearly exhibits an odd-even alternation and converges to 0. Although there is a similarity in the N dependence of the HOMO-LUMO gap between the three metal clusters, it is much stronger between the two noble metal clusters. The growth aspect of the d band below the Fermi level of the noble metal clusters with increasing N is presented. A good correspondence is obsd. in the d characteristic of the electronic states between the cluster composed of 75 atoms and the bulk metal. The similarities obsd. in the N dependence of the geometric structures and E(N)s originate from the similarity in that of the electronic structures. (c) 2009 American Institute of Physics.
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20Martin, T.; Bergmann, T.; Göhlich, H.; Lange, T. Observation of electronic shells and shells of atoms in large Na clusters. Chem. Phys. Lett. 1990, 172, 209– 213, DOI: 10.1016/0009-2614(90)85389-T20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXlslyluro%253D&md5=aed6875f56010d485d02a3a34dccdc20Observation of electronic shells and shells of atoms in large sodium clustersMartin, T. P.; Bergmann, T.; Goehlich, H.; Lange, T.Chemical Physics Letters (1990), 172 (3-4), 209-13CODEN: CHPLBC; ISSN:0009-2614.Intensity anomalies (magic nos.) have been obsd. in the mass spectra of sodium clusters contg. up to 22,000 atoms. For small clusters (Nan, n ≤ 1500) the anomalies appear to be due to the filling of electronic shells. The mass spectra of larger clusters are well explained by the completion of icosahedral or cuboctahedral shells of atoms.
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21Echt, O.; Sattler, K.; Recknagel, E. Magic numbers for sphere packings: experimental verification in free xenon clusters. Phys. Rev. Lett. 1981, 47, 1121– 1124, DOI: 10.1103/PhysRevLett.47.112121https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXlvFaksbw%253D&md5=acfec534d48a991573843edf80775ac5Magic numbers for sphere packings: experimental verification in free xenon clustersEcht, O.; Sattler, K.; Recknagel, E.Physical Review Letters (1981), 47 (16), 1121-4CODEN: PRLTAO; ISSN:0031-9007.The existence of magic nos. for the stability of at. microclusters was shown exptl. for the first time. The magic nos. n* were obsd. via the mass spectra of free Xe clusters, nucleated in the gas phase. The obsd. nos. n* = 13, 55, and 147 coincided with the nos. of hard spheres required for complete-shell icosahedra. The appearance of further magic nos. (19, 25, 71, and 87) was only partially explained by previous calcns.
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22Leuchtner, R.; Harms, A.; Castleman, A., Jr Thermal metal cluster anion reactions: Behavior of aluminum clusters with oxygen. J. Chem. Phys. 1989, 91, 2753– 2754, DOI: 10.1063/1.45698822https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXmt1Cjs7k%253D&md5=2bb6b90fdbc8ac4a3b3dac0d9c5f6948Thermal metal cluster anion reactions: behavior of aluminum clusters with oxygenLeuchtner, R. E.; Harms, A. C.; Castleman, A. W., Jr.Journal of Chemical Physics (1989), 91 (4), 2753-4CODEN: JCPSA6; ISSN:0021-9606.Aln- (n = 5-40) were produced by laser vaporization of an Al rod. Mass spectral data for the reaction of the clusters with O supports reactivity predictions of the electron droplet (jellium) model. Some anomalies suggest geometry may influence reactivity.
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23Leuchtner, R.; Harms, A.; Castleman, A., Jr Aluminum cluster reactions. J. Chem. Phys. 1991, 94, 1093– 1101, DOI: 10.1063/1.46071623https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXisFClur0%253D&md5=d934ef784876daa13139f82c465f4869Aluminum cluster reactionsLeuchtner, R. E.; Harms, A. C.; Castleman, A. W., Jr.Journal of Chemical Physics (1991), 94 (2), 1093-1101CODEN: JCPSA6; ISSN:0021-9606.Al clusters, both anion and cation, were produced by using laser vaporization and reacted under thermal conditions with O in a flow tube reactor. An etching reaction was obsd. and bimol. rate consts. are reported for Aln+, n = 1-33, and Aln-, n = 5-37. For Al7+, Al13-, and Al23- no apparent reactivity was obsd. (they are produced from larger species). These correspond to predicted jellium shell closings with 20, 40, and 70 electrons, resp. Besides these exceptions, and a small odd/even alternation in reaction rates, the overall reactivity is relatively insensitive to cluster size, and ranges between ∼1 × 10-12 and 5 × 10-12 cm3/s.
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24Gong, X.; Kumar, V. Enhanced stability of magic clusters: A case study of icosahedral Al12X, X = B, Al, Ga, C, Si, Ge, Ti, As. Phys. Rev. Lett. 1993, 70, 2078– 2081, DOI: 10.1103/PhysRevLett.70.207824https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXisVWitbo%253D&md5=ea6e57af771b455cd4e019d14ef59b91Enhanced stability of magic clusters: a case study of icosahedral X-doped aluminum clusters (Al12X, X = boron, aluminum, gallium, carbon, silicon, germanium, titanium, arsenic)Gong, X. G.; Kumar, VijayPhysical Review Letters (1993), 70 (14), 2078-81CODEN: PRLTAO; ISSN:0031-9007.The electronic structures and stabilities of some 40-valence-electron, icosahedral Al12X (X = B, Al, Ga, C, Si, Ge, Ti, and As) clusters were studied with the local-spin-d.-functional theory. The stability of the Al13 cluster can be substantially enhanced by proper doping. For neutral clusters, substitution of C at the center of the icosahedron leads to the largest gain in energy. However, Al12B- is the most strongly bound in this family. These results are in agreement with recent expts. that also found Al12B- to be highly abundant.
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25Wang, L.; Zhao, J.; Zhou, Z.; Zhang, S.; Chen, Z. First-principles study of molecular hydrogen dissociation on doped Al12X (X = B, Al, C, Si, P, Mg, and Ca) clusters. J. Comput. Chem. 2009, 30, 2509– 2514, DOI: 10.1002/jcc.2123925https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtF2ltLbM&md5=9fb68315f607903086837f215e72c8d0First-principles study of molecular hydrogen dissociation on doped Al12X (X = B, Al, C, Si, P, Mg, and Ca) clustersWang, Lu; Zhao, Jijun; Zhou, Zhen; Zhang, S. B.; Chen, ZhongfangJournal of Computational Chemistry (2009), 30 (15), 2509-2514CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)Inspired by the concept of superatom via substitutionally doping an Al13 magic cluster, the authors studied the H2 mol. dissocn. on the doped icosahedral Al12X (X = B, Al, C, Si, P, Mg, and Ca) clusters by d. functional theory. The computed reaction energies and activation barriers show that the concept of superatom is still valid for the catalysis behavior of doped metal clusters. The hydrogen dissocn. behavior on metal clusters characterized by the activation barrier and reaction energy can be tuned by controllable doping. Thus, doped Al12X clusters might serve as highly efficient and low-cost catalysts for hydrogen dissocn.
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26Castleman, A., Jr; Khanna, S. Clusters, superatoms, and building blocks of new materials. J. Phys. Chem. C 2009, 113, 2664– 2675, DOI: 10.1021/jp806850h26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXpsl2gsw%253D%253D&md5=894a99b3c61cd6c3cef6c9a2420e83beClusters, Superatoms, and Building Blocks of New MaterialsCastleman, A. W.; Khanna, S. N.Journal of Physical Chemistry C (2009), 113 (7), 2664-2675CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A review. The phys. and chem. properties of cluster systems at the subnano and nanoscale are often found to differ from those of the bulk and display a unique dependence on size, geometry, and compn. Indeed, most interesting are systems which have properties that vary discontinuously with the no. of atoms and compn., rather than scale linearly with size. This realm of cluster science where "one atom makes a difference" is undergoing an explosive growth in activity, and as a result of extensive collaborative activities through theory at VCU and expt. at PSU, our groups are recognized as pioneers in this area in which we have been active for many years. Herein we provide an overview of the field with primary focus on our joint undertakings which have spawned the superatom concept, giving rise to a 3-D periodic table of cluster elements and the prospect of using these as building blocks of new nanoscale materials with tailored properties.
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27Castleman, A., Jr From elements to clusters: The periodic table revisited. J. Phys. Chem. Lett. 2011, 2, 1062– 1069, DOI: 10.1021/jz200215s27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkvVSmt7c%253D&md5=2110113e2d8fb986bbb7e8bae183d114From Elements to Clusters: The Periodic Table RevisitedCastleman, A. W.Journal of Physical Chemistry Letters (2011), 2 (9), 1062-1069CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A review. Cluster science has given rise to the possibility of forming "superatoms", species that mimic elements of the periodic table but often display multiple functionalities. The ability to tailor the properties of these species opens up a new approach to forming nanoscale materials from the bottom up via cluster assembly. Recent success in designing these superatoms composing a "3D periodic table" and understanding the fundamentals governing their properties and stability are discussed, as well as prospects for the future of this field.
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28Luo, Z.; Castleman, A. W. Special and general superatoms. Acc. Chem. Res. 2014, 47, 2931– 2940, DOI: 10.1021/ar500158328https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhs1WhsL7I&md5=8d17921e2e1bb46d7a162197d88f0f43Special and General SuperatomsLuo, Zhixun; Castleman, A. WelfordAccounts of Chemical Research (2014), 47 (10), 2931-2940CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. Bridging the gap between atoms and macroscopic matter, clusters continue to be a subject of increasing research interest. Among the realm of cluster investigations, an exciting development is the realization that chosen stable clusters can mimic the chem. behavior of an atom or a group of the periodic table of elements. This major finding known as a superatom concept was originated exptl. from the study of aluminum cluster reactivity conducted in 1989 by noting a dramatic size dependence of the reactivity where cluster anions contg. a certain no. of Al atoms were unreactive toward oxygen while the other species were etched away. This observation was well interpreted by shell closings on the basis of the jellium model, and the related concept (originally termed "unified atom") spawned a wide range of pioneering studies in the 1990s pertaining to the understanding of factors governing the properties of clusters. Under the inspiration of a superatom concept, advances in cluster science in finding stable species not only shed light on magic clusters (i.e., superat. noble gas) but also enlightened the exploration of stable clusters to mimic the chem. behavior of atoms leading to the discovery of superhalogens, alk.-earth metals, superalkalis, etc. Among them, certain clusters could enable isovalent isomorphism of precious metals, indicating application potential for inexpensive superatoms for industrial catalysis, while a few superalkalis were found to validate the interesting "harpoon mechanism" involved in the superat. cluster reactivity; recently also found were the magnetic superatoms of which the cluster-assembled materials could be used in spin electronics. Up to now, extensive studies in cluster science have allowed the stability of superat. clusters to be understood within a few models, including the jellium model, also aromaticity and Wade-Mingos rules depending on the geometry and metallicity of the cluster. However, the scope of application of the jellium model and modification of the theory to account for nonspherical symmetry and nonmetal-doped metal clusters are still illusive to be further developed. It is still worth mentioning that a superatom concept has also been introduced in ligand-stabilized metal clusters which could also follow the major shell-closing electron count for a spherical, square-well potential. By proposing a new concept named as special and general superatoms, herein we try to summarize all these investigations in series, expecting to provide an overview of this field with a primary focus on the joint undertakings which have given rise to the superatom concept. To be specific, for special superatoms, we limit to clusters under a strict jellium model and simply classify them into groups based on their valence electron counts. While for general superatoms we emphasize on nonmetal-doped metal clusters and ligand-stabilized metal clusters, as well as a few isovalent cluster systems. Hopefully this summary of special and general superatoms benefits the further development of cluster-related theory, and lights up the prospect of using them as building blocks of new materials with tailored properties, such as inexpensive isovalent systems for industrial catalysis, semiconductive superatoms for transistors, and magnetic superatoms for spin electronics.
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29Jena, P. Beyond the periodic table of elements: The role of superatoms. J. Phys. Chem. Lett. 2013, 4, 1432– 1442, DOI: 10.1021/jz400156t29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXlslagtLY%253D&md5=36d3f2f3805cb14208bcb102e385aff9Beyond the Periodic Table of Elements: The Role of SuperatomsJena, PuruJournal of Physical Chemistry Letters (2013), 4 (9), 1432-1442CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A review. Atomic clusters composed of homo or heteroat. species constitute an intermediate phase of matter where every atom counts and whose properties depend on their size, shape, compn., and charge. If specific clusters mimicking the chem. of atoms can be produced, they can be thought of as man-made superatoms forming the building blocks of a new three-dimensional periodic table. Novel materials with tailored properties can then be synthesized by assembling these superatoms. This invited Perspective presents a brief summary of the pioneering works that led to this concept, and highlights the recent breakthroughs that hold promise for a new era in materials science.
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30Kroto, H. W.; Heath, J. R.; O’Brien, S. C.; Curl, R. F.; Smalley, R. E. C60: Buckminsterfullerene. Nature 1985, 318, 162– 163, DOI: 10.1038/318162a030https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XotVOktQ%253D%253D&md5=0ca5453a66ee1366682f56b357b40a10C60: buckminsterfullereneKroto, H. W.; Heath, J. R.; O'Brien, S. C.; Curl, R. F.; Smalley, R. E.Nature (London, United Kingdom) (1985), 318 (6042), 162-3CODEN: NATUAS; ISSN:0028-0836.Laser-induced vaporization of graphite produced a remarkably stable cluster, consisting of 60 C atoms. A truncated icosahedron is suggested, a polygon with 60 vertexes and 32 faces, 12 of which are pentagonal and 20 hexagonal. The C60 mol., which results when a C atom is placed at each vertex of this structure has all the valences satisfied by 2 single bonds and 1 double bond, has many resonance structures and appears to be arom.
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31Krätschmer, W.; Lamb, L. D.; Fostiropoulos, K.; Huffman, D. R. Solid C60: a new form of carbon. Nature 1990, 347, 354– 358, DOI: 10.1038/347354a0There is no corresponding record for this reference.
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32Hebard, A. F.; Rosseinsky, M. J.; Haddon, R. C.; Murphy, D. W.; Glarum, S. H.; Palstra, T. T. M.; Ramirez, A. P.; Kortan, A. R. Superconductivity at 18 K in Potassium-doped C60. Nature 1991, 350, 600– 601, DOI: 10.1038/350600a032https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXitF2htLk%253D&md5=d58148931e0f4d856eb82d45f8023f0cSuperconductivity at 18 K in potassium-doped fullerene (C60)Hebard, A. F.; Rosseinsky, M. J.; Haddon, R. C.; Murphy, D. W.; Glarum, S. H.; Palstra, T. T. M.; Ramirez, A. P.; Kortan, A. R.Nature (London, United Kingdom) (1991), 350 (6319), 600-1CODEN: NATUAS; ISSN:0028-0836.Low-temp. studies were made of potassium-doped C60 both as films and bulk samples. This material becomes superconducting. Supercond. is demonstrated by microwave, resistivity and Meissner-effect measurements. Both polycryst. powders and thin-film samples were studied. A thin film showed a resistance transition with an onset temp. of 16 K and essentially zero resistance near 5 K. Bulk samples show a well-defined Meissner effect and magnetic-field-dependent microwave absorption beginning at 18 K. The onset of supercond. at 18 K is the highest yet obsd. for a mol. superconductor.
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33Canham, L. T. Silicon quantum wire array fabrication by electrochemical and chemical dissolution of wafers. Appl. Phys. Lett. 1990, 57, 1046– 1048, DOI: 10.1063/1.10356133https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXmt1ahurc%253D&md5=7806af2e4e9274f981afaf5701503ef6Silicon quantum wire array fabrication by electrochemical and chemical dissolution of wafersCanham, L. T.Applied Physics Letters (1990), 57 (10), 1046-8CODEN: APPLAB; ISSN:0003-6951.Indirect evidence is presented that free-standing Si quantum wires can be fabricated without the use of epitaxial deposition or lithog. The novel approach uses electrochem. and chem. dissoln. steps to define networks of isolated wires out of bulk wafers. Mesoporous Si layers of high porosity exhibit visible (red) photoluminescence at room temps., observable with the naked eye under <1 mW unfocused (<0.1 W cm-2) green or blue laser line excitation. This is attributed to dramatic two-dimensional quantum size effects which can produce emission far above the band gap of bulk cryst. Si.
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34Uhlir, A., Jr Electrolytic shaping of germanium and silicon. Bell Syst. Tech. J. 1956, 35, 333– 347, DOI: 10.1002/j.1538-7305.1956.tb02385.x34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaG28XkslyhtA%253D%253D&md5=1934b9329e915ad3a4dfd6844e75494eElectrolytic shaping of germanium and siliconUhlir, Arthur, Jr.Bell System Technical Journal (1956), 35 (), 333-47CODEN: BSTJAN; ISSN:0005-8580.Electrolytic shaping (anodic soln.) techniques, making use of light sensitivity, rectifying barriers, appropriate voltage drops, masking, shaped cathodes, virtual cathodes, "thieves," jet impingement, injected carriers at p-n junctions, and various electrolytes permitted selection of these specialized factors to produce desired surface properties in Ge and Si intended for transistor or diode use. Voltage-current curves for both p and n Ge were given.
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35Bisi, O.; Ossicini, S.; Pavesi, L. Porous silicon: a quantum sponge structure for silicon based optoelectronics. Surf. Sci. Rep. 2000, 38, 1– 126, DOI: 10.1016/S0167-5729(99)00012-635https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXitl2hsLY%253D&md5=54c6700ca594f27656a54b483cac87fdPorous silicon: a quantum sponge structure for silicon based optoelectronicsBisi, O.; Ossicini, S.; Pavesi, L.Surface Science Reports (2000), 38 (1-3), 1-126CODEN: SSREDI; ISSN:0167-5729. (Elsevier Science B.V.)The striking photoluminescence properties of porous Si have attracted considerable research interest since their discovery in 1990. Luminescence is due to excitonic recombination quantum confined in Si nanocrystals which remain after the partial electrochem. dissoln. of Si. Porous Si is constituted by a nanocryst. skeleton (quantum sponge) immersed in a network of pores. As a result, porous Si was characterized by a very large internal surface area (of the order of 500 m2/cm3). This internal surface is passivated but remains highly chem. reactive which is one of the essential features of this new and complex material. The authors present an overview of the exptl. characterization and theor. modeling of porous Si, from the prepn. up to various applications. Emphasis is devoted to the optical properties of porous Si which are closely related to the quantum nature of the Si nanostructures. The characteristics of the various luminescence bands are analyzed and the underlying basic mechanisms are presented. In the quest of an efficient electroluminescent device, the authors survey the results for several porous Si contacts, with particular attention to the interface properties, to the stability requirement and to the carrier injection mechanisms. Other device applications are discussed as well. A review with 478 refs.
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36Beck, S. M. Studies of silicon cluster–metal atom compound formation in a supersonic molecular beam. J. Chem. Phys. 1987, 87, 4233– 4234, DOI: 10.1063/1.45287736https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXmslynug%253D%253D&md5=fd5c5e5f86786110bcaf4b478c1cf353Studies of silicon cluster-metal atom compound formation in a supersonic molecular beamBeck, Steven M.Journal of Chemical Physics (1987), 87 (7), 4233-4CODEN: JCPSA6; ISSN:0021-9606.MSi15 (M = Cr, Mo, W) were formed by seeding the He carrier gas with a small fraction of M(CO)6 which dissocd. during laser vaporization to form metal atoms in the nozzle throat which reacted with Si. Incorporation of the single metal atom in the Si15 and Si16 cluster stabilizes these clusters with respect to photofragmentation. The mechanisms involved in the formation of MSi15 and their structures are discussed.
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37Beck, S. M. Mixed metal–silicon clusters formed by chemical reaction in a supersonic molecular beam: implications for reactions at the metal/silicon interface. J. Chem. Phys. 1989, 90, 6306– 6312, DOI: 10.1063/1.45668437https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXkvV2gtLs%253D&md5=2d724a64fe8524caed019f7c12546e64Mixed metal-silicon clusters formed by chemical reaction in a supersonic molecular beam: implications for reactions at the metal/silicon interfaceBeck, Steven M.Journal of Chemical Physics (1989), 90 (11), 6306-12CODEN: JCPSA6; ISSN:0021-9606.A reaction was obsd. between a metal atom and Si in a supersonic jet to form metal atom-Si clusters. Using the technique of laser vaporization supersonic expansion with metal carbonyl seeded carrier gas, clusters of the form MSin were detected by ArF and F2 laser photoionization time-of-flight mass spectrometry. Three Group-VIB transition metals and Cu were investigated. The dominant product cluster peaks obsd. in the mass spectra obtained for all 3 Group VIB metals corresponds to identical but remarkable cluster stoichiometries. The dominant product peaks have formulas given by MSin (n = 16). Cu results are different than the other 3 metals, indicating the importance of the metal valence electronic structure to the chem. The metal-semiconductor clusters are relatively more stable towards photofragmentation than the bare Si-cluster of the same size. The observation of these new species may be relevant to reactions which occur at the interface between a Si wafer and deposited metals.
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38Heath, J.; O’brien, S.; Zhang, Q.; Liu, Y.; Curl, R.; Tittel, F.; Smalley, R. Lanthanum complexes of spheroidal carbon shells. J. Am. Chem. Soc. 1985, 107, 7779– 7780, DOI: 10.1021/ja00311a10238https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XhsVSkuw%253D%253D&md5=fa85fc7aec246351f0c1c9ec022bd730Lanthanum complexes of spheroidal carbon shellsHeath, J. R.; O'Brien, S. C.; Zhang, Q.; Liu, Y.; Curl, R. F.; Tittel, F. K.; Smalley, R. E.Journal of the American Chemical Society (1985), 107 (25), 7779-80CODEN: JACSAT; ISSN:0002-7863.La complexes with C clusters were prepd. in a mol. beam by laser vaporization of a La-impregnated graphite disk mounted in a pulsed supersonic nozzle. Detection was accomplished by photoionization with an excimer laser, followed by time-of-flight mass spectrometry. The major obsd. La complexes were of the form CnLa (n = 44, 46, 48, ... 76) with C60La being the dominant species. No complexes were obsd. contg. >1 La atom. The only abundant bare clusters of C under these conditions were C60 and C70 which are believed to be closed, hollow shells made up of 5- and 6-membered arom. rings. All the CnLa complexes probably have the metal atom strongly bound within a spheroidal C shell.
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39Lu, X.; Chen, Z. Curved pi-conjugation, aromaticity, and the related chemistry of small fullerenes (< C60) and single-walled carbon nanotubes. Chem. Rev. 2005, 105, 3643– 3696, DOI: 10.1021/cr030093d39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVGisrfM&md5=d395bd7e490810ad684705169068e3d9Curved Pi-Conjugation, Aromaticity, and the Related Chemistry of Small Fullerenes (<C60) and Single-Walled Carbon NanotubesLu, Xin; Chen, ZhongfangChemical Reviews (Washington, DC, United States) (2005), 105 (10), 3643-3696CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review.
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40Rodríguez-Fortea, A.; Balch, A. L.; Poblet, J. M. Endohedral metallofullerenes: a unique host–guest association. Chem. Soc. Rev. 2011, 40, 3551– 3563, DOI: 10.1039/c0cs00225a40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXns12nu7o%253D&md5=86e8417e506e62c3499052e45ab977a0Endohedral metallofullerenes: a unique host-guest associationRodriguez-Fortea, Antonio; Balch, Alan L.; Poblet, Josep M.Chemical Society Reviews (2011), 40 (7), 3551-3563CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. In this tutorial review taking x-ray crystallog. characterized compds. as a starting point a walk is taken through the electronic and structural properties of endohedral metallofullerenes. After classification of the fullerenes according to the encapsulated guest, particular attention is given to identifying factors that det. the selection of a particular carbon cage network by the internal metal cluster. Some of the phys. rules that det. which particular fullerene cage is formed is discussed. Concepts such as charge transfer between the cage and the guest metal ions, the topol. of the cage, the sepns. between the 12 pentagons on the fullerene surface, and the effect of entropic factors were used to rationalize the selection of a particular cage. The roles of electrochem. and vibrational spectroscopy in combination with theor. calcns. are considered in understanding the structures of the endohedral fullerenes.
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41Lu, X.; Feng, L.; Akasaka, T.; Nagase, S. Current status and future developments of endohedral metallofullerenes. Chem. Soc. Rev. 2012, 41, 7723– 7760, DOI: 10.1039/c2cs35214a41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38fptl2msg%253D%253D&md5=ff60dcf7aaa967055584a42b42eecef0Current status and future developments of endohedral metallofullerenesLu Xing; Feng Lai; Akasaka Takeshi; Nagase ShigeruChemical Society reviews (2012), 41 (23), 7723-60 ISSN:.Endohedral metallofullerenes (EMFs), a new class of hybrid molecules formed by encapsulation of metallic species inside fullerene cages, exhibit unique properties that differ distinctly from those of empty fullerenes because of the presence of metals and their hybridization effects via electron transfer. This critical review provides a balanced but not an exhaustive summary regarding almost all aspects of EMFs, including the history, the classification, current progress in the synthesis, extraction, isolation, and characterization of EMFs, as well as their physiochemical properties and applications in fields such as electronics, photovoltaics, biomedicine, and materials science. Emphasis is assigned to experimentally obtained results, especially the X-ray crystallographic characterizations of EMFs and their derivatives, rather than theoretical calculations, although the latter has indeed enhanced our knowledge of metal-cage interactions. Finally, perspectives related to future developments and challenges in the research of EMFs are proposed. (381 references).
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42Popov, A. A.; Yang, S.; Dunsch, L. Endohedral fullerenes. Chem. Rev. 2013, 113, 5989– 6113, DOI: 10.1021/cr300297r42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmvVylsLk%253D&md5=a62bdab20b10c9be7d071a394cb8d31cEndohedral FullerenesPopov, Alexey A.; Yang, Shangfeng; Dunsch, LotharChemical Reviews (Washington, DC, United States) (2013), 113 (8), 5989-6113CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review is given on endohedral fullerenes with topics including the synthesis, mol. structures, electronic structures, spectroscopic and photophys. properties, electrochem. and spectroelectrochem., chem. and magnetic properties and potential applications.
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43Garcia-Borras, M.; Osuna, S.; Luis, J. M.; Swart, M.; Solà, M. The role of aromaticity in determining the molecular structure and reactivity of (endohedral metallo) fullerenes. Chem. Soc. Rev. 2014, 43, 5089– 5105, DOI: 10.1039/C4CS00040D43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtValsrbN&md5=80afbc881b0a995c33a8704ae3d330d5The role of aromaticity in determining the molecular structure and reactivity of (endohedral metallo)fullerenesGarcia-Borras, Marc; Osuna, Silvia; Luis, Josep M.; Swart, Marcel; Sola, MiquelChemical Society Reviews (2014), 43 (14), 5089-5105CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)The encapsulation of metal clusters in endohedral metallofullerenes (EMFs) takes place in cages that in most cases are far from being the most stable isomer in the corresponding hollow fullerenes. There exist several possible explanations for the choice of the hosting cages in EMFs, although the final reasons are actually not totally well understood. Moreover, the reactivity and regioselectivity of (endohedral metallo)fullerenes have in the past decade been shown to be generally dependent on a no. of factors, such as the size of the fullerene cage, the type of cluster that is being encapsulated, and the no. of electrons that are transferred formally from the cluster to the fullerene cage. Different rationalizations of the obsd. trends had been proposed, based on bond lengths, pyramidalization angles, shape and energies of (un)occupied orbitals, deformation energies of the cages, or sepn. distances between the pentagon rings. Recently, in our group we proposed that the quest for the max. aromaticity (max. aromaticity criterion) dets. the most suitable hosting carbon cage for a given metallic cluster (i.e. EMF stabilization), including those cases where the IPR rule is not fulfilled. Moreover, we suggested that local aromaticity plays a detg. role in the reactivity of EMFs, which can be used as a criterion for understanding and predicting the regioselectivity of different reactions such as Diels-Alder cycloaddns. or Bingel-Hirsch reactions. This review highlights different aspects of the aromaticity of fullerenes and EMFs, starting from how this can be measured and ending by how it can be used to rationalize and predict their mol. structure and reactivity.
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44Yang, S.; Wei, T.; Jin, F. When metal clusters meet carbon cages: endohedral clusterfullerenes. Chem. Soc. Rev. 2017, 46, 5005– 5058, DOI: 10.1039/C6CS00498A44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFamsbvL&md5=cd358f606c5696cc06ad4a6ae3761f68When metal clusters meet carbon cages: endohedral clusterfullerenesYang, Shangfeng; Wei, Tao; Jin, FeiChemical Society Reviews (2017), 46 (16), 5005-5058CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Fullerenes have the characteristic of a hollow interior, and this unique feature triggers intuitive inspiration to entrap atoms, ions or clusters inside the carbon cage in the form of endohedral fullerenes. In particular, upon entrapping an otherwise unstable metal cluster into a carbon cage, the so-called endohedral clusterfullerenes fulfil the mutual stabilization of the inner metal cluster and the outer fullerene cage with a specific isomeric structure which is often unstable as an empty fullerene. A variety of metal clusters have been reported to form endohedral clusterfullerenes, including metal nitrides, carbides, oxides, sulfides, cyanides and so on, making endohedral clusterfullerenes the most variable and intriguing branch of endohedral fullerenes. In this review article, we present an exhaustive review on all types of endohedral clusterfullerenes reported to date, including their discoveries, syntheses, sepns., mol. structures and properties as well as their potential applications in versatile fields such as biomedicine, energy conversion, and so on. At the end, we present an outlook on the prospect of endohedral clusterfullerenes.
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45Guo, T.; Diener, M. D.; Chai, Y.; Alford, M. J.; Haufler, R. E.; McClure, S. M.; Ohno, T.; Weaver, J. H.; Scuseria, G. E.; Smalley, R. E. Uranium stabilization of C28: a tetravalent fullerene. Science 1992, 257, 1661– 1664, DOI: 10.1126/science.257.5077.166145https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXjt1SitQ%253D%253D&md5=7a8b09e735da3708d18554472a7ac412Uranium stabilization of C28: a tetravalent fullereneGuo, Ting; Diener, M. D.; Chai, Yan; Alford, M. J.; Haufler, R. E.; McClure, S. M.; Ohno, T.; Weaver, J. H.; Scuseria, G. E.; Smalley, R. E.Science (Washington, DC, United States) (1992), 257 (5077), 1661-4CODEN: SCIEAS; ISSN:0036-8075.Laser vaporization expts. with graphite in a supersonic cluster beam app. indicate that the smallest fullerene to form in substantial abundance is C28. Although ab initio quantum chem. calcns. predict that this cluster will favor a tetrahedral cage structure, it is electronically open shell. Further calcns. reveal that C28 in this structure should behave as a sort of hollow superatom with an effective valence of 4. This tetravalence should be exhibited toward chem. bonding both on the outside and on the inside of the cage. Stable closed-shell derivs. of C28 with large HOMO-LUMO gaps should be attainable either by reacting at the 4 tetrahedral vertices on the outside of the C28 cage to make, for example, C28H4, or by trapping a tetravalent atom inside the cage to make endohedral fullerenes such as Ti@C28. An example of this 2nd, inside route to C28 stabilization is reported here: the laser and C-arc prodn. of U@C28.
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46Jackson, K.; Nellermoe, B. Zr@Si20: a strongly bound Si endohedral system. Chem. Phys. Lett. 1996, 254, 249– 256, DOI: 10.1016/0009-2614(96)00315-646https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XjtlSksrg%253D&md5=83902e304da97e9b0919492f3e218c95Zr@Si20: a strongly bound Si endohedral systemJackson, Koblar; Nellermoe, BritaChemical Physics Letters (1996), 254 (3,4), 249-256CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)We present the results of local-d.-approxn. (LDA) calcns. for a novel Si endohedral system, Zr@Si20. We compute an LDA endohedral binding energy for this system of 11.2 eV with respect to an isolated Zr atom and the most stable Si20 isomer known. To understand the remarkable binding in this system, we compare the electronic structure of Zr@Si20 with that of the corresponding bare cluster and with other Si20 endohedral systems. We find that the bonding of all the endohedrals can be understood on the basis of a simple model previously used to explain endohedral bonding in small carbon fullerenes. Prospects for producing Zr@Si20 exptl. are discussed.
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47Hiura, H.; Miyazaki, T.; Kanayama, T. Formation of metal-encapsulating Si cage clusters. Phys. Rev. Lett. 2001, 86, 1733– 1736, DOI: 10.1103/PhysRevLett.86.173347https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXhsVWltrg%253D&md5=4a430bb1f6b302273818f6170e42f037Formation of Metal-Encapsulating Si Cage ClustersHiura, Hidefumi; Miyazaki, Takehide; Kanayama, ToshihikoPhysical Review Letters (2001), 86 (9), 1733-1736CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report the formation of a series of metal-contg. hydrogenated silicon clusters using an ion trap. Mass analyses reveal that many types of transition metal ions M+ (M = Hf, Ta, W, Re, Ir) react with silane (SiH4) to form dehydrogenated MSi+n cluster ions (n = 14, 13, 12, 11, 9, resp.) as an end product, indicating that the metal atom is endohedral and stabilizes the Si polyhedral cage. This finding is confirmed by our ab initio calcn. that WSi12 is a W-encapsulating Si12 cage cluster, and is very stable owing to both the electronic and the geometrical shell closures.
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48Kumar, V.; Kawazoe, Y. Metal-encapsulated fullerenelike and cubic caged clusters of silicon. Phys. Rev. Lett. 2001, 87, 045503, DOI: 10.1103/PhysRevLett.87.04550348https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXltFGntro%253D&md5=2a5661eacc13b7837a75e22d47d22fe6Metal-Encapsulated Fullerenelike and Cubic Caged Clusters of SiliconKumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2001), 87 (4), 045503/1-045503/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report metal-encapsulated caged clusters of silicon from ab initio pseudopotential plane wave calcns. using generalized gradient approxn. for the exchange-correlation energy. Depending upon the size of the metal (M) atom, silicon forms fullerenelike M@Si16, M = Hf, Zr, and cubic M@Si14, M = Fe, Ru, Os, caged clusters. The embedding energy of the M atom is ≈12 eV due to strong M-Si interactions that make the cage compact. Bonding in these clusters is predominantly covalent and the HOMO-LUMO gap is ≈1.5 eV. However, an exceptionally large gap (2.35 eV) was obtained for Ti@Si16 Frank-Kasper polyhedron. Interaction between these clusters is weak, making them attractive for cluster-assembled materials.
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49Kumar, V.; Kawazoe, Y. Erratum: Metal-Encapsulated Fullerenelike and Cubic Caged Clusters of Silicon [Phys. Rev. Lett. 87, 045503 (2001)]. Phys. Rev. Lett. 2003, 91, 199901, DOI: 10.1103/PhysRevLett.91.19990149https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVWjsro%253D&md5=55df60c904899b2ff6ccc79bef07f2f2Metal-encapsulated fullerenelike and cubic caged clusters of silicon. [Erratum to document cited in CA135:294195]Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2003), 91 (19), 199901/1CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)The fullerenelike (f) and the Frank-Kasper (FK) isomers of the Hf@Si16 cluster were reported to be nearly degenerate. The data of the binding energy, embedding energy, and the HOMO-LUMO gap presented in Table 1 for the FK isomer actually correspond to a slightly different FK isomer that was called tetracapped hexagonal antiprism [Figure 1(b)] for the metal-encapsulated Ge clusters in which one hexagon is capped by one Si atom while the other hexagon is capped by three Si atoms. This isomer and the FK isomer differ in the orientation of this capping trimer. Starting with the initial structure of the FIK isomer, a local shallow min. was obtained in which the FK isomer nearly converged with forces becoming ≈ 0.005 eV/Å or less on each ion. This lies about 0.075 eV higher in energy with the HOMO-LUMO gap of about 2.48 eV as compared to the hexagonal antiprism isomer. Starting with the coordinates of the FK local min. obtained in the optimization process, the structure was reoptimized and the FK isomer was found to have a min. with 0.07 eV higher energy than the hexagonal antiprism and 0.488 eV HOMO-LUMO gap. The energy difference between the two FK-type forms is quite small and the HOMO-LUMO gaps are similar, though the tetrahedral symmetry of the FK isomer is lowered to 3-fold symmetry in the hexagonal antiprism isomer that lifts the degeneracies of some of the levels. The differences in the bond lengths in the two isomers are small. These results also suggest low frequency modes in the vibrational spectra of the FK-type isomers of these and related clusters representing the slow rotational motion of the trimer. The overall conclusions of the paper are not affected.
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50O’brien, S.; Heath, J.; Curl, R.; Smalley, R. Photophysics of buckminsterfullerene and other carbon cluster ions. J. Chem. Phys. 1988, 88, 220– 230, DOI: 10.1063/1.45464050https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXosFWrsw%253D%253D&md5=4e46c8769ba31b4aad27c076012f123aPhotophysics of buckminsterfullerene and other carbon cluster ionsO'Brien, S. C.; Heath, J. R.; Curl, R. F.; Smalley, R. E.Journal of Chemical Physics (1988), 88 (1), 220-30CODEN: JCPSA6; ISSN:0021-9606.The laser-induced fragmentation behavior of pos. C cluster ions was investigated by tandem time-of-flight techniques for the jet-cooled clusters up to 80 atoms in size. Two distinct photophys. regimes were found. The first applies to clusters with 34 atoms or more, all of which dissoc. to produce even numbered fragments. Large even clusters fragment by the loss of the high energy species C2, odd ones lose a C atom. The second regime applies to clusters composed of 31 or less atoms, all of which fragment by the loss of C3. These 2 regimes are sharply sepd. by C32+ which fragments to produce smaller cluster ions in the 10-19 atom size range. Fragmentation of the large clusters occurs on a microsecond or faster time scale only at very high levels of excitation (>12.8 eV). These photophys. results are interpreted as consequences of the large clusters having edgeless, spheroidal cage structures while the small ones have linear chain or ring structures.
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51Zhu, X.; Zeng, X. C.; Lei, Y.; Pan, B. Structures and stability of medium silicon clusters. II. Ab initio molecular orbital calculations of Si12–Si20. J. Chem. Phys. 2004, 120, 8985– 8995, DOI: 10.1063/1.169075551https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjs1SmsLg%253D&md5=19c9070ce5f7a6d050ea2847ab9699a1Structures and stability of medium silicon clusters. II. Ab initio molecular orbital calculations of Si12-Si20Zhu, X. L.; Zeng, X. C.; Lei, Y. A.; Pan, B.Journal of Chemical Physics (2004), 120 (19), 8985-8995CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Ab initio all-electron mol.-orbital calcns. are carried out to study the structures and relative stability of low-energy silicon clusters (Sin,n=12-20). Selected geometric isomers include those predicted by Ho et al. [Nature (London) 392, 582 (1998)] based on an unbiased search with tight-binding/genetic algorithm, as well as those found by Rata et al. [Phys. Rev. Lett. 85, 546 (2000)] based on d.-functional tight-binding/single-parent evolution algorithm. These geometric isomers are optimized at the Moller-Plesset (MP2) MP2/6-31G(d) level. The single-point energy at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d) level for several low-lying isomers are further computed. Harmonic vibrational frequency anal. at the MP2/6-31G(d) level of theory is also undertaken to assure that the optimized geometries are stable. For Si12-Si17 and Si19 the isomer with the lowest-energy at the CCSD(T)/6-31G(d) level is the same as that predicted by Ho et al., whereas for Si18 and Si20, the same as predicted by Rata et al. However, for Si14 and Si15, the vibrational frequency anal. indicates that the isomer with the lowest CCSD(T)/6-31G(d) single-point energy gives rise to imaginary frequencies. Small structural perturbation onto the Si14 and Si15 isomers can remove the imaginary frequencies and results in new isomers with slightly lower MP2/6-31G(d) energy; however the new isomers have a higher single-point energy at the CCSD(T)/6-31G(d) level. For most Sin (n=12-18,20) the low-lying isomers are prolate in shape, whereas for Si19 a spherical-like isomer is slightly lower in energy at the CCSD(T)/6-31G(d) level than low-lying prolate isomers.
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52Yoo, S.; Zeng, X. C. Structures and stability of medium-sized silicon clusters. III. Reexamination of motif transition in growth pattern from Si15 to Si20. J. Chem. Phys. 2005, 123, 164303, DOI: 10.1063/1.204312752https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFyktb3F&md5=3273463d6f7d4538027915c866a40cd2Structures and stability of medium-sized silicon clusters. III. Reexamination of motif transition in growth pattern from Si15 to Si20Yoo, Soohaeng; Zeng, X. C.Journal of Chemical Physics (2005), 123 (16), 164303/1-164303/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)It has been established from expts. that stable medium-sized ionic clusters Si15-Si20 are prolate in shape. D.-functional theories (DFTs) also predict that nearly all low-lying neutral clusters in this size range are prolate in shape. Moreover, most of them are built onto two generic structural motifs, either the tricapped-trigonal-prism (TTP) Si9 motif or the six/six Si6/Si6 (sixfold-puckered hexagonal ring Si6 plus six-atom tetragonal bipyramid Si6) motif. However, it appears that the exact location of the TTP-to-six/six motif transition is dependent on the functional (e.g., PBE or BLYP) used in the DFT calcns. Here, we present total-energy calcns. for two series of clusters (one series contg. six/six motif and the other contg. the TTP motif) in the size range of Si16-Si20. The calcns. were based on all-electron DFT methods with a medium [6-311G (2d)] and a large (cc-pVTZ) basis sets, as well as coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] method with a modest (cc-pVDZ) basis set. In the DFT calcns., two popular hybrid d. functionals, the B3LYP and PBE1PBE, were selected. It is found that the B3LYP total-energy calcns. slightly favor the six/six motif, whereas the PBE1PBE calcns. slightly favor the TTP motif. The CCSD(T) total-energy calcns., however, show that isomers based on the six/six motif are energetically slightly favorable in the size range of Si16-Si20. Hence, the TTP-to-six/six motif transition is more likely to occur at Si16.
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53Kumar, V.; Kawazoe, Y. Metal-encapsulated caged clusters of germanium with large gaps and different growth behavior than silicon. Phys. Rev. Lett. 2002, 88, 235504, DOI: 10.1103/PhysRevLett.88.23550453https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktFGktrw%253D&md5=7957953eb0c806b2548aef1fdfd39426Metal-encapsulated caged clusters of germanium with large gaps and different growth behavior than siliconKumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2002), 88 (23), 235504/1-235504/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Metal (M)-encapsulated caged clusters of Ge are studied using the ab initio pseudopotential plane-wave method and the generalized gradient approxn. for the exchange-correlation energy. Depending upon the size of the M atom, we find Frank-Kasper polyhedral M@Ge16 for M = Ti, Zr, Hf, and capped decahedral or cubic M@Ge14 and M@Ge15 clusters for several M atoms. The growth behavior differs from the one found in M@Sin clusters. The HOMO-LUMO gaps are, however, similarly large or even higher in some cases. Cr@Ge16 and Fe@Ge15 are magnetic. The weak interaction between the clusters makes such species attractive for cluster assembled materials.
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54Ohara, M.; Koyasu, K.; Nakajima, A.; Kaya, K. Geometric and electronic structures of metal (M)-doped silicon clusters (M = Ti, Hf, Mo and W). Chem. Phys. Lett. 2003, 371, 490– 497, DOI: 10.1016/S0009-2614(03)00299-954https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXitlWkt70%253D&md5=5becb923578baf48e1073c69d91ece98Geometric and electronic structures of metal (M)-doped silicon clusters (M = Ti, Hf, Mo and W)Ohara, Michiaki; Koyasu, Kiichirou; Nakajima, Atsushi; Kaya, KojiChemical Physics Letters (2003), 371 (3,4), 490-497CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The authors have studied geometric and electronic structures of metal (M) atom doped Si clusters, MSin (M = Ti, Hf, Mo and W), using mass spectrometry, a chem.-probe method and photoelectron spectroscopy. In the mass spectra for all of the mixed cluster anions, MSin-, both MSi15- and MSi16- were abundantly produced compared to neighbors. Together with the result of the adsorption reactivity and photoelectron spectroscopy, one metal atom can be encapsulated inside a Sin cage at n ≥ 15.
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55Koyasu, K.; Akutsu, M.; Mitsui, M.; Nakajima, A. Selective formation of MSi16 (M = Sc, Ti, and V). J. Am. Chem. Soc. 2005, 127, 4998– 4999, DOI: 10.1021/ja045380t55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXisVyqurs%253D&md5=76d3de747d57b19477f76b148d78e678Selective Formation of MSi16 (M = Sc, Ti, and V)Koyasu, Kiichirou; Akutsu, Minoru; Mitsui, Masaaki; Nakajima, AtsushiJournal of the American Chemical Society (2005), 127 (14), 4998-4999CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Metal-encapsulated silicon cage clusters are a new class of clusters and are opening up new avenues for silicon-based nanoscale materials. We present exptl. evidence for a highly stable cluster corresponding to M@Si16 (M = Sc, Ti, and V). Mass spectrometry and anion photoelectron spectroscopy show that the cluster features an electronically closed TiSi16 neutral core which undergoes a change in the no. of valence electrons involving (i) substitution of neighboring metals with Sc and V, or (ii) addn. of a halogen atom to the TiSi16 anion, and that VSi16F is predicted to form an ionically bound superatom complex.
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56Lau, J.; Hirsch, K.; Klar, P.; Langenberg, A.; Lofink, F.; Richter, R.; Rittmann, J.; Vogel, M.; Zamudio-Bayer, V.; Möller, T. X-ray spectroscopy reveals high symmetry and electronic shell structure of transition-metal-doped silicon clusters. Phys. Rev. A: At., Mol., Opt. Phys. 2009, 79, 053201, DOI: 10.1103/PhysRevA.79.05320156https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXmvF2mtLY%253D&md5=1d2818be2c778d20965efdeb4ae27c18X-ray spectroscopy reveals high symmetry and electronic shell structure of transition-metal-doped silicon clustersLau, J. T.; Hirsch, K.; Klar, Ph.; Langenberg, A.; Lofink, F.; Richter, R.; Rittmann, J.; Vogel, M.; Zamudio-Bayer, V.; Moller, T.; von Issendorff, B.Physical Review A: Atomic, Molecular, and Optical Physics (2009), 79 (5, Pt. A), 053201/1-053201/5CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)Size-selected cationic transition-metal-doped Si clusters were studied with x-ray absorption spectroscopy at the transition-metal L2,3 edges to study the local electronic structure of the dopant atoms. For VSi16+, the x-ray absorption spectrum is dominated by sharp transitions which directly reveal the formation of a highly sym. Si cage around the V atom. In spite of their different no. of valence electrons, a nearly identical local electronic structure is found for the dopant atoms in TiSi16+, VSi16+, and CrSi16+. This indicates strongly interlinked electronic and geometric properties: while the transition-metal atom imposes a geometric rearrangement on the Si cluster, the interaction with the highly sym. Si cage dets. the local electronic structure of the transition-metal dopant.
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57Furuse, S.; Koyasu, K.; Atobe, J.; Nakajima, A. Experimental and theoretical characterization of MSi16–, MGe16–, MSn16–, and MPb16– (M = Ti, Zr, and Hf): The role of cage aromaticity. J. Chem. Phys. 2008, 129, 064311, DOI: 10.1063/1.296600557https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVShsbjP&md5=3ac612f41f0eaf33d2de5fd75a8f7710Experimental and theoretical characterization of MSi16-, MGe16-,MSn16-, and MPb16- (M=Ti, Zr, and Hf): The role of cage aromaticityFuruse, Shunsuke; Koyasu, Kiichirou; Atobe, Junko; Nakajima, AtsushiJournal of Chemical Physics (2008), 129 (6), 064311/1-064311/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Silicon (Si), germanium (Ge), tin (Sn), and lead (Pb) clusters mixed with a group-4 transition metal atom [M=titanium (Ti), zirconium (Zr), and hafnium (Hf)] were generated by a dual-laser vaporization method, and their properties were analyzed by means of time-of-flight mass spectroscopy and anion photoelectron spectroscopy together with theor. calcns. In the mass spectra, mixed neutral clusters of MSi16, MGe16, and MSn16 were produced specifically, but the yield of MPb16 was low. The anion photoelectron spectra revealed that MSi16, MGe16, and MSn16 neutrals have large HOMO-LUMO gaps of 1.5-1.9 eV compared to those of MPb16 (0.8-0.9 eV), implying that MSi16, MGe16, and MSn16 are evidently electronically stable clusters. Cage aromaticity appears to be an important determinant of the electronic stability of these clusters: Calcns. of nucleus-independent chem. shifts (NICSs) show that Si164-, Ge164-, and Sn164- have arom. characters with neg. NICS values, while Pb164- has an antiarom. character with a pos. NICS value. (c) 2008 American Institute of Physics.
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58Kumar, V.; Singh, A. K.; Kawazoe, Y. Smallest magic caged clusters of Si, Ge, Sn, and Pb by encapsulation of transition metal atom. Nano Lett. 2004, 4, 677– 681, DOI: 10.1021/nl049807658https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXit1SqtLg%253D&md5=c1bf16896d5acd3af214941e5956cb91Smallest magic caged clusters of Si, Ge, Sn, and Pb by encapsulation of transition metal atomKumar, Vijay; Singh, Abhishek Kumar; Kawazoe, YoshiyukiNano Letters (2004), 4 (4), 677-681CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Ten atom clusters of X = Si, Ge, Sn, and Pb are known to be magic, suggesting that addn. of an atom to such clusters is generally unfavorable. However, here the authors report using an ab initio ultrasoft pseudopotential method that these clusters can be further stabilized by doping of a Ni or Pt atom, leading to some of the smallest metal encapsulated clusters of these elements. For Si and Ge, doping of Ni is optimal while for Sn and Pb, Pt is the best. The results agree with the recent observations of strong abundances and magic nature of X10Co- clusters of these elements. These findings could lead to the development of novel cluster-based nanomaterials for optoelectronic and other nanoscale applications.
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59Neukermans, S.; Janssens, E.; Chen, Z.; Silverans, R.; Schleyer, P. v. R.; Lievens, P. Extremely stable metal-encapsulated AlPb10+ and AlPb12+ clusters: Mass-Spectrometric discovery and density functional theory study. Phys. Rev. Lett. 2004, 92, 163401, DOI: 10.1103/PhysRevLett.92.16340159https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjvFKiurk%253D&md5=4712b9d400cfc4fe67eab6d409c75681Extremely stable metal-encapsulated AlPb10+ and AlPb12+ clusters: Mass-spectrometric discovery and density functional theory studyNeukermans, S.; Janssens, E.; Chen, Z. F.; Silverans, R. E.; Schleyer, P. v. R.; Lievens, P.Physical Review Letters (2004), 92 (16), 163401/1-163401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report the exptl. discovery of extremely stable metal-encapsulated superatom clusters of a group IVA element: AlPb10+ and AlPb12+. Ab initio d. functional geometry optimizations at the B3LYP/LANL2DZ level result in a perfect icosahedron with an exceptionally large HOMO-LUMO gap of 3.1 eV for AlPb12+, and a related structure with D4d symmetry for AlPb10+, with a HOMO-LUMO gap of 2.6 eV. Their high stability is attributed to the reinforcing influence of the most favorable closed-packed structure and optimally filled electron shells.
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60Lv, J.; Wang, Y.; Zhang, L.; Lin, H.; Zhao, J.; Ma, Y. Stabilization of fullerene-like boron cages by transition metal encapsulation. Nanoscale 2015, 7, 10482– 10489, DOI: 10.1039/C5NR01659B60https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXotVKksb0%253D&md5=79b5f0726024ac47a37711ca216e7552Stabilization of fullerene-like boron cages by transition metal encapsulationLv, Jian; Wang, Yanchao; Zhang, Lijun; Lin, Haiqing; Zhao, Jijun; Ma, YanmingNanoscale (2015), 7 (23), 10482-10489CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The stabilization of fullerene-like boron (B) cages in the free-standing form has been long sought after and a challenging problem. Studies that have been carried out for more than a decade have confirmed that the planar or quasi-planar polymorphs are energetically favored ground states over a wide range of small and medium-sized B clusters. Recently, the breakthroughs represented by Nat.Chem., 2014, 6, 727 established that the transition from planar/quasi-planar to cage-like Bn clusters occurs around n = ∼38-40, paving the way for understanding the intriguing chem. of B-fullerene. We herein demonstrate that the transition demarcation, n, can be significantly reduced with the help of transition metal encapsulation. We explore via extensive first-principles swarm-intelligence based structure searches the free energy landscapes of B24 clusters doped by a series of transition metals and find that the low-lying energy regime is generally dominated by cage-like isomers. This is in sharp contrast to that of bare B24 clusters, where the quasi-planar and rather irregular polyhedrons are prevalent. Most strikingly, a highly sym. B cage with D3h symmetry is discovered in the case of Mo or W encapsulation. The endohedral D3h cages exhibit robust thermodn., dynamic and chem. stabilities, which can be rationalized in terms of their unique electronic structure of an 18-electron closed-shell configuration. Our results indicate that transition metal encapsulation is a feasible route for stabilizing medium-sized B cages, offering a useful roadmap for the discovery of more B fullerene analogs as building blocks of nanomaterials.
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61Pyykkö, P.; Runeberg, N. Icosahedral WAu12: A predicted closed-shell species, stabilized by aurophilic attraction and relativity and in accord with the 18-electron rule. Angew. Chem., Int. Ed. 2002, 41, 2174– 2176, DOI: 10.1002/1521-3773(20020617)41:12<2174::AID-ANIE2174>3.0.CO;2-861https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XltVWgtbk%253D&md5=8f35b742cc8f65f1f5aa2db92ab9f3b0Icosahedral WAu12: a predicted closed-shell species, stabilized by aurophilic attraction and relativity and in accord with the 18-electron rulePyykko, Pekka; Runeberg, NinoAngewandte Chemie, International Edition (2002), 41 (12), 2174-2176CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)The authors present ab initio HF-MP2-B3LYP studies of isoelectronic MAu12 clusters (M = Ta-, W, Re+, Au5+). Data are presented on bond length, force consts., Raman frequencies, orbital energies, HOMO-LUMO gaps.
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62Li, X.; Kiran, B.; Li, J.; Zhai, H. J.; Wang, L. S. Experimental observation and confirmation of icosahedral W@Au12 and Mo@Au12 molecules. Angew. Chem., Int. Ed. 2002, 41, 4786– 4789, DOI: 10.1002/anie.20029004862https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhtFCnsQ%253D%253D&md5=807cfe0412aa043f46aca3ff6f80b64eExperimental observation and confirmation of icosahedral WαAu12 and MoαAu12 moleculesLi, Xi; Kiran, Boggavarapu; Li, Jun; Zhai, Hua-Jin; Wang, Lai-ShengAngewandte Chemie, International Edition (2002), 41 (24), 4786-4789CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Icosahedral WαAu12 clusters were characterized using anion photoelectron spectroscopy (PES) and relativistic d. functional theory (DFT) calcns. Icosahedral MoαAu12 mols. were also characterized and were found to have a nearly identical structure and electronic spectrum as WαAu12, suggesting that a series of highly stable and sym. MαAu12 clusters with M= 4d elements might also exist. The WAu12- (MoAu12-) cluster was produced using laser vaporization of a mixed-Au/W (or Mo) target (approx. 10:1 at. ratio) and a helium carrier gas. The anion photoelectron spectra and theor. calcd. electron-detachment energies indicate that the WαAu12 cluster indeed has a highly sym. icosahedral structure with significant stability. The exptl. results of the MoαAu12 cluster suggest that MαAu12 clusters contg. a 4d-central atom are also stable.
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63Veldeman, N.; Höltzl, T.; Neukermans, S.; Veszprémi, T.; Nguyen, M. T.; Lievens, P. Experimental observation and computational identification of Sc@Cu16+, a stable dopant-encapsulated copper cage. Phys. Rev. A: At., Mol., Opt. Phys. 2007, 76, 011201, DOI: 10.1103/PhysRevA.76.01120163https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXpvFCltbc%253D&md5=3da1291ca21697807c6014441555548bExperimental observation and computational identification of Sc@Cu+16, a stable dopant-encapsulated copper cageVeldeman, Nele; Holtzl, Tibor; Neukermans, Sven; Veszpremi, Tamas; Nguyen, Minh Tho; Lievens, PeterPhysical Review A: Atomic, Molecular, and Optical Physics (2007), 76 (1, Pt. A), 011201/1-011201/4CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)We report a combined exptl. and computational study of scandium doped copper clusters. The clusters are studied with time-of-flight mass spectrometry after laser fragmentation. Enhanced stabilities for specific cluster sizes in the mass abundance spectra are discussed using both electronic (shell closing) and geometric (symmetry) arguments. The exceptional stability obsd. for Cu16Sc+ is investigated in detail computationally. D. functional geometry optimizations at the Becke-Perdew 1986-LANL 2-double-zeta (BP86/LANL2DZ) level result in a Frank-Kasper tetrahedron, encapsulating a scandium atom in a highly coordinated position. The high stability is therefore interpreted in terms of extremely stable dopant encapsulated structures featuring a closed electron shell. The thermodn. stability, as indicated by the stable backbone and large binding energy per atom, the relatively small ionization energy, and the moderate electron affinity of the neutral Cu16Sc cluster show that it has a superatom character, chem. similar to the alk.-metal atoms.
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64Hakkinen, H.; Yoon, B.; Landman, U.; Li, X.; Zhai, H. J.; Wang, L. S. On the electronic and atomic structures of small AuN- (N=4-14) clusters: A photoelectron spectroscopy and density-functional study. J. Phys. Chem. A 2003, 107, 6168– 6175, DOI: 10.1021/jp035437iThere is no corresponding record for this reference.
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65Huang, W.; Wang, L.-S. Probing the 2D to 3D structural transition in gold cluster anions using argon tagging. Phys. Rev. Lett. 2009, 102, 153401, DOI: 10.1103/PhysRevLett.102.15340165https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXkslKntrc%253D&md5=5c3879e2f87984c8e64711b0bc09d807Probing the 2D to 3D Structural Transition in Gold Cluster Anions Using Argon TaggingHuang, Wei; Wang, Lai-ShengPhysical Review Letters (2009), 102 (15), 153401/1-153401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Different physisorption properties by 2D and 3D isomers of Aun- clusters are obsd. and used to probe the 2D to 3D structural transition. Strong Ar clustering occurs on planar Aun- and the planar faces of the pyramidal Au20-. An abrupt change of Ar clustering at Au12- confirms the 2D to 3D structural transition at this size, where both isomers coexist. The minor 2D isomer can be titrated out by Ar to produce a clean 3D-Au12- beam and beams of Au12Arm- with enhanced 2D isomers. Using the Ar titrn. and tagging, isomer-specific photoelectron spectra for the 2D and 3D Au12- are obtained.
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66Jian, T.; Chen, X.; Li, S.-D.; Boldyrev, A. I.; Li, J.; Wang, L.-S. Probing the structures and bonding of size-selected boron and doped-boron clusters. Chem. Soc. Rev. 2019, 48, 3550– 3591, DOI: 10.1039/C9CS00233B66https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtVWktb3I&md5=a7d20fdc4510c8ed0d426f03ca9e883fProbing the structures and bonding of size-selected boron and doped-boron clustersJian, Tian; Chen, Xuenian; Li, Si-Dian; Boldyrev, Alexander I.; Li, Jun; Wang, Lai-ShengChemical Society Reviews (2019), 48 (13), 3550-3591CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Because of their interesting structures and bonding and potentials as motifs for new nanomaterials, size-selected boron clusters have received tremendous interest in recent years. In particular, boron cluster anions (Bn-) have allowed systematic joint photoelectron spectroscopy and theor. studies, revealing predominantly two-dimensional structures. The discovery of the planar B36 cluster with a central hexagonal vacancy provided the first exptl. evidence of the viability of 2D borons, giving rise to the concept of borophene. The finding of the B40 cage cluster unveiled the existence of fullerene-like boron clusters (borospherenes). Metal-doping can significantly extend the structural and bonding repertoire of boron clusters. Main-group metals interact with boron through s/p orbitals, resulting in either half-sandwich-type structures or substitutional structures. Transition metals are more versatile in bonding with boron, forming a variety of structures including half-sandwich structures, metal-centered boron rings, and metal-centered boron drums. Transition metal atoms have also been found to be able to be doped into the plane of 2D boron clusters, suggesting the possibility of metalloborophenes. Early studies of di-metal-doped boron clusters focused on gold, revealing ladder-like boron structures with terminal gold atoms. Recent observations of highly sym. Ta2B6- and Ln2Bn- (n = 7-9) clusters have established a family of inverse sandwich structures with monocyclic boron rings stabilized by two metal atoms. The study of size-selected boron and doped-boron clusters is a burgeoning field of research. Further investigations will continue to reveal more interesting structures and novel chem. bonding, paving the foundation for new boron-based chem. compds. and nanomaterials.
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67Kumar, V.; Kawazoe, Y. Metal-doped magic clusters of Si, Ge, and Sn: The finding of a magnetic superatom. Appl. Phys. Lett. 2003, 83, 2677– 2679, DOI: 10.1063/1.160966167https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXns1CgsrY%253D&md5=9574dc45155c06849f0aff57364cb149Metal-doped magic clusters of Si, Ge, and Sn: The finding of a magnetic superatomKumar, Vijay; Kawazoe, YoshiyukiApplied Physics Letters (2003), 83 (13), 2677-2679CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Studies on divalent-metal (M)-atom-doped XNM (X = Si, Ge, and Sn, N = 8-12 and 14) clusters, using ab initio pseudopotential plane wave method, show that the known nine- and ten-atom capped prism units as well as 12- and 14-atom clusters of these elements can transform to magic clusters with higher symmetries and larger highest occupied-LUMO gaps. Most strikingly doping of X12 with Mn leads to an icosahedral superatom, Mn@X12, X = Ge and Sn with a high magnetic moment of 5 μB, enriching the family of M-doped clusters of semiconductors for possible nanodevice applications.
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68Rohrmann, U.; Schäfer, R. Stern-Gerlach experiments on Mn@Sn12: Identification of a paramagnetic superatom and vibrationally induced spin orientation. Phys. Rev. Lett. 2013, 111, 133401, DOI: 10.1103/PhysRevLett.111.13340168https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1amtrrM&md5=63814b1f5fd6b637c846637bff53e0a9Stern-Gerlach experiments on Mn@Sn12: identification of a paramagnetic superatom and vibrationally induced spin orientationRohrmann, Urban; Schaefer, RolfPhysical Review Letters (2013), 111 (13), 133401/1-133401/5CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Beam deflection expts. in inhomogeneous magnetic fields reveal a new limiting case of the magnetization distribution of isolated clusters. Endohedrally doped clusters are produced in a temp. controlled, cryogenically cooled laser ablation source. Temp. dependent expts. indicate a crucial contribution of mol. vibrations to the spin dynamics of Mn@Sn12. In its vibrational ground state the cluster behaves magnetically like a paramagnetic atom, with quantized spin states. However, excited mol. vibrations induce spin orientation in the magnetic field.
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69Rohrmann, U.; Schwerdtfeger, P.; Schäfer, R. Atomic domain magnetic nanoalloys: interplay between molecular structure and temperature dependent magnetic and dielectric properties in manganese doped tin clusters. Phys. Chem. Chem. Phys. 2014, 16, 23952– 23966, DOI: 10.1039/C4CP02994A69https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVOhu7jL&md5=62a2f6bbf1441ba2205364e1eeac70bdAtomic domain magnetic nanoalloys: interplay between molecular structure and temperature dependent magnetic and dielectric properties in manganese doped tin clustersRohrmann, Urban; Schwerdtfeger, Peter; Schaefer, RolfPhysical Chemistry Chemical Physics (2014), 16 (43), 23952-23966CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The authors present extensive temp. dependent (16-70 K) magnetic and elec. mol. beam deflection measurements on neutral Mn doped Sn clusters Mn/SnN (N = 9-18). Cluster geometries are identified by comparison of elec. deflection profiles and quantum chem. data obtained from DFT calcns. Most clusters adopt endohedral cage structures and all clusters exhibit nonvanishing magnetic dipole moments. In the high temp. regime all species show exclusively high field seeking magnetic response and the magnetic dipole moments are extd. from the shift of the mol. beam. At low nozzle temps., some of the clusters show considerably broadened beam profiles due to nonuniform deflection in the magnetic field. The results reflect the influence of the chem. environment on the magnetic properties of the transition metal in at. domain magnetic nanoalloys. Different ground state spin multiplicities and coupling of rotational and vibrational degrees of freedom with the spin angular momentum of isolated clusters of different size apparently cause these variations of spin orientation. This is discussed by taking electronic and mol. structure data into account.
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70Zhang, M.; Zhang, J.; Feng, X.; Zhang, H.; Zhao, L.; Luo, Y.; Cao, W. Magnetic superatoms in VLin (n = 1–13) clusters: A first-principles prediction. J. Phys. Chem. A 2013, 117, 13025– 13036, DOI: 10.1021/jp410489g70https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslOmsrfL&md5=c1d5a9e26c9fe9adaf738c8ff3e28b5fMagnetic Superatoms in VLin (n = 1-13) Clusters: A First-Principles PredictionZhang, Meng; Zhang, Jianfei; Feng, Xiaojuan; Zhang, Hongyu; Zhao, Lixia; Luo, Youhua; Cao, WeiJournal of Physical Chemistry A (2013), 117 (48), 13025-13036CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The authors demonstrated a first-principles investigation to search for magnetic superatoms in the vanadium-doped lithium clusters VLin (n = 1-13). The stabilities of VLin clusters were detd. through geometrical and electronic optimizations. The growth pattern of VLin in 3-space follows adding a Li atom capped on VLin-1 clusters. All doped clusters show larger relative binding energies compared with pure Lin+1 partners and display tunable magnetic properties. When n = 8-13, the VLin clusters adopt a cage-like structure with an endohedral V atom and are identified as superatoms with their magnetic moments successively decreasing from 5 to 0 μB. The isolated VLi8 superatom is emphasized due to its robust magnetic moment as well as high structural and chem. stability analogous of a single Mn2+ ion. MOs anal. shows that VLi8 has an electronic configuration of 1S21P61D5, exhibiting Hund's filling rule of maximizing the spin-like atoms. Electronic shell structures of 1S2 and 1P6 are virtually unchanged in Li9 cluster as the V atom substitutes for the embedded Li atom, indicating that the electron-shell-closing model is valid for explaining its structures and stabilities. The results show that the tailored magnetic building blocks for nanomaterials can be formed by seeding magnetic dopants into alkali metal cluster cages.
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71Reveles, J. U.; Clayborne, P. A.; Reber, A. C.; Khanna, S. N.; Pradhan, K.; Sen, P.; Pederson, M. R. Designer magnetic superatoms. Nat. Chem. 2009, 1, 310– 315, DOI: 10.1038/nchem.24971https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnsFOjtbc%253D&md5=b6f34fdcdf807f64e46f6c856c8dd5c6Designer magnetic superatomsReveles, J. Ulises; Clayborne, Penee A.; Reber, Arthur C.; Khanna, Shiv N.; Pradhan, Kalpataru; Sen, Prasenjit; Pederson, Mark R.Nature Chemistry (2009), 1 (4), 310-315, S310/1-S310/8CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)The quantum states in metal clusters are grouped into bunches of close-lying eigenvalues, termed electronic shells, similar to those of atoms. Filling of the electronic shells with paired electrons results in local min. in energy to give stable species called magic clusters. Selected clusters mimic chem. properties of elemental atoms on the periodic table and can be classified as superatoms. So far the work on superatoms has focused on nonmagnetic species. Here the authors propose a framework for magnetic superatoms by invoking systems that have both localized and delocalized electronic states, in which localized electrons stabilize magnetic moments and filled nearly-free electron shells lead to stable species. An isolated VCs8 and a ligated MnAu24(SH)18 are such magnetic superatoms. The magnetic superatoms' assemblies could be ideal for mol. electronic devices, as the coupling could be altered by charging or weak fields.
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72Medel, V. M.; Reveles, J. U.; Khanna, S. N.; Chauhan, V.; Sen, P.; Castleman, A. W. Hund’s rule in superatoms with transition metal impurities. Proc. Natl. Acad. Sci. U. S. A. 2011, 108, 10062– 10066, DOI: 10.1073/pnas.110012910872https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXot1egtLc%253D&md5=6454824c981b5f89659604e3b2bd49eeHund's rule in superatoms with transition metal impuritiesMedel, Victor M.; Reveles, Jose Ulises; Khanna, Shiv N.; Chauhan, Vikas; Sen, Prasenjit; Castleman, A. WelfordProceedings of the National Academy of Sciences of the United States of America (2011), 108 (25), 10062-10066, S10062/1-S10062/5CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The quantum states in metal clusters bunch into supershells with assocd. orbitals having shapes resembling those in atoms, giving rise to the concept that selected clusters could mimic the characteristics of atoms and be classified as superatoms. Unlike atoms, the superatom orbitals span over multiple atoms and the filling of orbitals does not usually exhibit Hund's rule seen in atoms. Here, we demonstrate the possibility of enhancing exchange splitting in superatom shells via a composite cluster of a central transition metal and surrounding nearly free electron metal atoms. The transition metal d states hybridize with superatom D states and result in enhanced splitting between the majority and minority sets where the moment and the splitting can be controlled by the nature of the central atom. We demonstrate these findings through studies on TMMgn clusters where TM is a 3 d atom. The clusters exhibit Hund's filling, opening the pathway to superatoms with magnetic shells.
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73Ge, G.-X.; Han, Y.; Wan, J.-G.; Zhao, J.-J.; Wang, G.-H. First-principles prediction of magnetic superatoms in 4d-transition-metal-doped magnesium clusters. J. Chem. Phys. 2013, 139, 174309, DOI: 10.1063/1.482751573https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslWqtLbE&md5=289f227a187fd798b76954564a4415efFirst-principles prediction of magnetic superatoms in 4d-transition-metal-doped magnesium clustersGe, Gui-Xian; Han, Yan; Wan, Jian-Guo; Zhao, Ji-Jun; Wang, Guang-HouJournal of Chemical Physics (2013), 139 (17), 174309/1-174309/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The authors theor. predict magnetic superatoms in the 4d-transition-metal-doped Mg8 clusters using a spin-polarized d. functional theory method. TcMg8 is highly energetically stable in both structure and magnetic states, and identify it as a magnetic superatom with a magnetic moment as large as 5 μB. The magnetic TcMg8 with 23 valence electrons has a configuration of 1S21P61D10 closed shell and 2S12D4 open shell, complying with Hund's rule similar to the single atom. The authors elucidate the formation mechanism of the magnetic TcMg8 superatom based on the detailed anal. of MOs, and attribute it to the large exchange interaction and moderate crystal field effect. Finally, the authors predict that the magnetic TcMg8 may exhibit semiconductor-like property with spin polarization characteristics. (c) 2013 American Institute of Physics.
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74Chauhan, V.; Medel, V. M.; Reveles, J. U.; Khanna, S. N.; Sen, P. Shell magnetism in transition metal doped calcium superatom. Chem. Phys. Lett. 2012, 528, 39– 43, DOI: 10.1016/j.cplett.2012.01.03474https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XisVyhs7o%253D&md5=f6239afe44521519917da825e8ca6b24Shell magnetism in transition metal doped calcium superatomChauhan, Vikas; Medel, Victor M.; Ulises Reveles, J.; Khanna, Shiv N.; Sen, PrasenjitChemical Physics Letters (2012), 528 (), 39-43CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Clusters of metallic elements with valence electron counts 2, 8, 18, 20, ... are known to be stable with filled electronic shells and large gaps between shells. Through first principles DFT studies of TMCa8 (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) clusters we identify a stable magnetic FeCa8 cluster of 24 valence electrons distributed into a closed 1S2 1P6 1D10 2S2 shell sequence and with four electrons occupying the majority 2Dxy, 2Dx2-y2, 2Dxz and 2Dyz levels while the unfilled 2Dz2 level is sepd. by a large energy gap of 0.61 eV arising from at. deformation and exchange splitting.
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75Medel, V. M.; Reveles, J. U.; Islam, M. F.; Khanna, S. N. Robust magnetic moments on impurities in metallic clusters: Localized magnetic states in superatoms. J. Phys. Chem. A 2013, 117, 4297– 4303, DOI: 10.1021/jp401273575https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmtlekurw%253D&md5=2793cdf238b86adb0d96881a2e45d227Robust Magnetic Moments on Impurities in Metallic Clusters: Localized Magnetic States in SuperatomsMedel, Victor M.; Reveles, J. Ulises; Islam, M. Fhokrul; Khanna, Shiv N.Journal of Physical Chemistry A (2013), 117 (20), 4297-4303CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Introducing magnetic impurities into clusters of simple metals can create localized states for higher angular momentum quantum nos. (l = 2 or 3) that can breed magnetism analogous to that in virtual bound states in metallic hosts, offering a new recipe for magnetic superatoms. MnCan clusters contg. 6-15 Ca atoms show a spin magnetic moment of 5.0 μB irresp. of the cluster size. Theor. anal. reveals that the Mn d states hybridize only partially with superat. states and introduce extra majority and minority d states, largely localized at the Mn site, with a large gap. Successive addn. of Ca atoms introduces superat. states of varying angular momentum that are embedded in this gap, allowing control over the stability of the motifs without altering the moment. Assemblies of such clusters can offer novel electronic features due to the formation of localized magnetic quasibound states in a confined nearly free electron gas.
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76Medel, V.; Reveles, J. U.; Khanna, S. N. Magnetism of electrons in atoms and superatoms. J. Appl. Phys. 2012, 112, 064313, DOI: 10.1063/1.475247176https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlOlsLrN&md5=5cd1e1b7398e52fc2bdb05e13c277eadMagnetism of electrons in atoms and superatomsMedel, Victor; Reveles, J. Ulises; Khanna, Shiv N.Journal of Applied Physics (2012), 112 (6), 064313/1-064313/7CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)The quantum states of electrons in small sym. metallic clusters are grouped into shells similar to the electronic shells in free atoms, leading to the conceptual basis for defining superatoms. The filling of the electronic shells in clusters, however, do not follow Hund's rule and usually result in non-magnetic species. By embedding a transition metal in group II atoms, one can stabilize superatoms with unpaired electronic supershells. We demonstrate this intriguing effect through electronic structure studies of MnSrn (n = 6-12) clusters within first principles generalized gradient calcns. The studies identify an unusually stable magnetic MnSr9 species with a large exchange splitting of 1.82 eV of the superat. D-states. The exchange split d-states in the Mn atom induce exchange splitting in S and D superat. shells because of the hybridization between orbitals of selected parity. The magnetic MnSr9 cluster with 25 valence electrons has filled 1S2, 1P6, 1D10, 2S2 shells, making it highly stable, and an open shell of 5 unpaired D electrons breeding the magnetic moment. The stable cluster is resistant to collapse as two motifs are united to form a supermol. (c) 2012 American Institute of Physics.
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77Pradhan, K.; Reveles, J. U.; Sen, P.; Khanna, S. Enhanced magnetic moments of alkali metal coated Sc clusters: New magnetic superatoms. J. Chem. Phys. 2010, 132, 124302, DOI: 10.1063/1.336772277https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjvFGgt7o%253D&md5=bcfa8fe863d97ed12c8e861f6d9b8302Enhanced magnetic moments of alkali metal coated Sc clusters: New magnetic superatomsPradhan, Kalpataru; Reveles, J. Ulises; Sen, Prasenjit; Khanna, S. N.Journal of Chemical Physics (2010), 132 (12), 124302/1-124302/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The magnetic moments of Sc atoms can be significantly enhanced by combining them with alkali atoms. The authors results of first principles electronic structure calcns. of ScNan(1 ≤ n ≤ 12) clusters that indicate that a ScNa12 cluster consisting of a Sc atom surrounded by 12 Na atoms forming a compact icosahedral structure has a spin magnetic moment of 3μB that is three times that of an isolated Sc atom. This unusual behavior is analyzed in terms of the filling of the supershells 1S, 1P,... controlled by the nature and size of the alkali atoms and the more localized Sc 3d orbitals that hybridize weakly with Na sp orbitals. Even larger magnetic moments could be attained by controlling the relative position of 1S, 1P, and 3d states. Indeed, the studies indicate large magnetic moment five times that of an isolated Sc atom in the ScK12 and ScCs12 clusters, in which the 3d orbitals of Sc adopt a half-filled configuration, while the clusters are stabilized by filled 1S2, 1P6, and 2S2 shells, the features making them as new magnetic superatoms. (c) 2010 American Institute of Physics.
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78González-Ramírez, H.; Ulises Reveles, J.; Gómez-Sandoval, Z. High magnetic moments on binary yttrium-alkali superatoms. Chem. Phys. Lett. 2013, 583, 97– 102, DOI: 10.1016/j.cplett.2013.07.06278https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlSntbvK&md5=76ad407689058ee66dd44165cc5f84e3High magnetic moments on binary yttrium-alkali superatomsGonzalez-Ramirez, Henry; Ulises Reveles, J.; Gomez-Sandoval, Z.Chemical Physics Letters (2013), 583 (), 97-102CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)First principles electronic structure calcns. guided by energetic and magnetic principles of stability are conducted to predict and investigate a series of yttrium doped alkali clusters with a compact icosahedral structure and a large spin magnetic moment. The energetic stability of the YM12 (M = K, Rb and Cs) species lies on the nature of their electronic configuration and is a result of the controlled hybridization of the 4d-Y levels with the sp-alkali states. Further, the integrity of the YK12 is found to be conserved in a (YK12)2 dimer attesting for its potential as a magnetic building block for nanostructure materials.
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79Zhang, X.; Wang, Y.; Wang, H.; Lim, A.; Gantefoer, G.; Bowen, K. H.; Reveles, J. U.; Khanna, S. N. On the existence of designer magnetic superatoms. J. Am. Chem. Soc. 2013, 135, 4856– 4861, DOI: 10.1021/ja400830z79https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjsFakt7Y%253D&md5=3219b8f27465d8688f97a26afcea77c5On the Existence of Designer Magnetic SuperatomsZhang, Xinxing; Wang, Yi; Wang, Haopeng; Lim, Alane; Gantefoer, Gerd; Bowen, Kit H.; Reveles, J. Ulises; Khanna, Shiv N.Journal of the American Chemical Society (2013), 135 (12), 4856-4861CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The quantum states in small, compact metal clusters are bunched into electronic shells with electronic orbitals resembling those in atoms, enabling classification of stable clusters as superatoms. The filling of super at. orbitals, however, does not generally follow Hund's rule, and probably magnetic superatoms can should be stabilized by doping simple metal clusters with magnetic atoms. Here, the authors present evidence of the existence of a magnetic superatom and the detn. of its spin moment. The authors' approach combines 1st principles studies with neg. ion photoelectron expts. and enables a unique identification of the ground state and spin multiplicity. The studies indicate VNa8 to be a magnetic superatom with a filled d-subshell and a magnetic moment of 5.0 μB. Its low electron affinity is consistent with filled subshell and enhanced stability. The synthesis of this species opens the pathway to study the spin-dependent electronics of the new magnetic motifs.
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80Tsunoyama, H.; Akatsuka, H.; Shibuta, M.; Iwasa, T.; Mizuhata, Y.; Tokitoh, N.; Nakajima, A. Development of integrated Dry–Wet synthesis method for metal encapsulating silicon cage superatoms of M@Si16 (M = Ti and Ta). J. Phys. Chem. C 2017, 121, 20507– 20516, DOI: 10.1021/acs.jpcc.7b0644980https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtl2ls73P&md5=ba0f73e8bdac017a39b3a71ba1d82304Development of Integrated Dry-Wet Synthesis Method for Metal Encapsulating Silicon Cage Superatoms of M@Si16 (M = Ti and Ta)Tsunoyama, Hironori; Akatsuka, Hiroki; Shibuta, Masahiro; Iwasa, Takeshi; Mizuhata, Yoshiyuki; Tokitoh, Norihiro; Nakajima, AtsushiJournal of Physical Chemistry C (2017), 121 (37), 20507-20516CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Nanoclusters (NCs) of several to hundreds of atoms in size are prospective functional units for future nanomaterials originating in their unique, size-specific properties. To explore the field of NC-based materials science, the development of large-scale, size-exclusive synthesis methods is in high demand, as one can see from the successful evolution of fullerene science. The authors have developed a large-scale synthesis method for main group-based NC compds. by scaling up the clean dry-process with a high-power impulse magnetron sputtering. The 100 mg scale synthesis of binary NCs of M@Si16 (M = Ti and Ta) stabilized by poly(ethylene glycol) di-Me ether enables the authors to characterize their structures by an array of methods, for example, mass spectroscopy, x-ray photoemission spectroscopy, Raman spectroscopy, and 29Si NMR. Spectroscopic evidence indicates that the M@Si16 NCs are the metal-encapsulating tetrahedral silicon-cage structure satisfying the 68 electrons, closed-electronic-shell superatom.
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81Weinert, B.; Dehnen, S. Clusters–Contemporary Insight in Structure and Bonding; Springer, 2016; pp 99– 134.There is no corresponding record for this reference.
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82Mayer, K.; Weßing, J.; Fässler, T. F.; Fischer, R. A. Intermetalloid clusters: molecules and solids in a dialogue. Angew. Chem., Int. Ed. 2018, 57, 14372– 14393, DOI: 10.1002/anie.20180589782https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhslOltr3N&md5=daf88674f23e01fe73f0fba7f062d15cIntermetalloid Clusters: Molecules and Solids in a DialogueMayer, Kerstin; Wessing, Jana; Faessler, Thomas F.; Fischer, Roland A.Angewandte Chemie, International Edition (2018), 57 (44), 14372-14393CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Atom-precise, ligand-stabilized metalloid clusters have emerged as outstanding model systems to study fundamental structure and bonding situations of compositionally related mols. and extended solid phases. However, this fascinating field of research is still largely restricted to homometallic and pseudo-heterometallic systems of closely related d-block metals. In this review, we will highlight our own and others' efforts to project the structural and compositional diversity of intermetallics with dissimilar d- and p-block metal combinations, particularly the Zintl and Hume-Rothery phases, onto the mol. level in order to bridge the still gaping chasm between heterometallic mol. coordination chem. and solid-state intermetallics. Herein, fundamental synthetic approaches, as well as structural and electronic properties of thus accessible "mol. alloys" will be addressed, and placed against their exceptional position as intermediates on the way to nanomaterials.
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83Wilson, R. J.; Weinert, B.; Dehnen, S. Recent developments in Zintl cluster chemistry. Dalton Trans. 2018, 47, 14861– 14869, DOI: 10.1039/C8DT03174F83https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhslGns7rP&md5=da6f158313aff3bc38ff446293caac9bRecent developments in Zintl cluster chemistryWilson, Robert J.; Weinert, Bastian; Dehnen, StefanieDalton Transactions (2018), 47 (42), 14861-14869CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)A review. Zintl anions were known for more than a century and were studied systematically by Eduard Zintl in the 1930s. Since then, they were studied for their interesting structures, bonding, and phys. properties - in solid Zintl phases, in solvate salts, and in soln. While their popularity remained limited for several decades, Zintl ion chem. has recently experienced a renaissance as a result of breakthroughs regarding their modifications into multinary anions that include transition metal atoms, their org. derivatization, and their oxidative linkage. A plethora of reports from the past two decades - demonstrating the ever growing variety of Zintl ion chem. - were since summarized in several review articles. Herein, the authors intend to present the most recent developments, which also shed light on Zintl anions and clusters as useful precursors for materials development, as illustrated by one recent example.
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84Scharfe, S.; Kraus, F.; Stegmaier, S.; Schier, A.; Faessler, T. F. Zintl ions, cage compounds, and intermetalloid clusters of group 14 and group 15 elements. Angew. Chem., Int. Ed. 2011, 50, 3630– 3670, DOI: 10.1002/anie.20100163084https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkt12jtr0%253D&md5=682afff80519bbc8bbbb6a3c9e5c623aZintl Ions, Cage Compounds, and Intermetalloid Clusters of Group 14 and Group 15 ElementsScharfe, Sandra; Kraus, Florian; Stegmaier, Saskia; Schier, Annette; Faessler, Thomas F.Angewandte Chemie, International Edition (2011), 50 (16), 3630-3670CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Discussion focuses on the enormous progress that has been made in Group 14 and Group 15 element Zintl ion chem. with an emphasis on syntheses, properties, structures, and theor. treatments. For a long time, Zintl ions of Group 14 and 15 elements were considered to be remarkable species domiciled in solid-state chem. that have unexpected stoichiometries and fascinating structures, but were of limited relevance. The revival of Zintl ions was heralded by the observation that these species, preformed in solid-state Zintl phases, can be extd. from the lattice of the solids and dissolved in appropriate solvents, and thus become available as reactants and building blocks in soln. chem. The recent upsurge of research activity in this fast-growing field has now provided a rich plethora of new compds., for example by substitution of these Zintl ions with org. groups and organometallic fragments, by oxidative coupling reactions leading to dimers, oligomers, or polymers, or by the inclusion of metal atoms under formation of endohedral cluster species and intermetalloid compds.; some of these species have good prospects in applications in materials science.
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85Fässler, T. F.; Hoffmann, S. D. Endohedral Zintl ions: intermetalloid clusters. Angew. Chem., Int. Ed. 2004, 43, 6242– 6247, DOI: 10.1002/anie.20046042785https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFWrt7fF&md5=e3a61bbb0c7e1cd58c288d5deffe4fa8Endohedral clusters: Endohedral Zintl ions: Intermetalloid clustersFassler, Thomas F.; Hoffmann, Stephan D.Angewandte Chemie, International Edition (2004), 43 (46), 6242-6247CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. The close race between Zintl ions and fullerides has gone into the second round, initialized by the synthesis of the sol. endohedral cluster [Pt@Pb12]2-. The structural characterization of an anion with almost ideal icosahedral symmetry illustrates that many heteroat. clusters obsd. in the gas phase can, indeed, be regarded as endohedral clusters.
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86Liu, C.; Sun, Z.-M. Recent advances in structural chemistry of Group 14 Zintl ions. Coord. Chem. Rev. 2019, 382, 32– 56, DOI: 10.1016/j.ccr.2018.12.00386https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXis1WnsrnN&md5=91c88db6953bcd3aeb02d3386889f651Recent advances in structural chemistry of Group 14 Zintl ionsLiu, Chao; Sun, Zhong-MingCoordination Chemistry Reviews (2019), 382 (), 32-56CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)The soln. chem. of Group 14 Zintl-type clusters is of growing interest as a result of their potential to be used as mol. building blocks for the construction of nanoscale architectures. Here we review the synthesis of homoat. and heteroat. Group 14 Zintl anions, with particular emphasis on their direct coordination to org. species, main-group elements and transition metal fragments.
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87Wilson, R. J.; Lichtenberger, N.; Weinert, B.; Dehnen, S. Intermetalloid and Heterometallic Clusters Combining p-Block (Semi) Metals with d-or f-Block Metals. Chem. Rev. 2019, 119, 8506– 8554, DOI: 10.1021/acs.chemrev.8b0065887https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtVensb7E&md5=cfe3350077cbe5e05bde96049ab99a78Intermetalloid and Heterometallic Clusters Combining p-Block (Semi)Metals with d- or f-Block MetalsWilson, Robert J.; Lichtenberger, Niels; Weinert, Bastian; Dehnen, StefanieChemical Reviews (Washington, DC, United States) (2019), 119 (14), 8506-8554CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. Clusters have been the subject of intense investigations since their famous definition launched by Cotton in 1963, and the area has expanded ever since. One obvious development addresses the widening of the definition of what to call a cluster: from purely (transition) metal-metal linked assemblies, as per Cotton's early denomination, to nonmetal/metal clusters or purely nonmetal cages, like fullerenes, and even noncovalent aggregates such as water clusters. The other extension concerns the broadened spectrum of compns. within the aforementioned cluster types and their corresponding structures that range from trinuclear motifs to clusters with sizes in the range of the Hb unit. This review article reports on one cluster family that has its origins in traditional Zintl anion chem. but has undergone rapid development in recent years, namely, ligand-free clusters that combine main group and transition metal atoms. Depending on the position of the transition metal atom(s), one refers to such clusters as intermetalloid (endohedral) clusters or as a special type of heterometallic clusters. The predominant synthetic access makes use of sol. Zintl anions. Other pathways for their prepn. include traditional solid state reactions of according element combinations or bottom-up syntheses employing low valent organo-main group element sources. This survey will shed light on all of these approaches, with an emphasis on the syntheses that employ sol. Zintl anion compds. The article will give a comprehensive overview of the currently known compds., their different synthesis protocols, and analytic techniques for detn. of their compns., structures, and further properties. Addnl., this survey will report peculiarities of bonding situations found within some of the cluster mols., which were studied by means of sophisticated quantum chem. investigations.
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88Klemm, W. Metalloids and their compounds with the alkali metals. P. Chem. Soc. 1958, 329– 364There is no corresponding record for this reference.
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89Guloy, A. M.; Ramlau, R.; Tang, Z.; Schnelle, W.; Baitinger, M.; Grin, Y. A guest-free germanium clathrate. Nature 2006, 443, 320– 323, DOI: 10.1038/nature0514589https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xpslaks78%253D&md5=8c9ca3feff831cfa80e53b67a4f23a71A guest-free germanium clathrateGuloy, Arnold M.; Ramlau, Reiner; Tang, Zhongjia; Schnelle, Walter; Baitinger, Michael; Grin, YuriNature (London, United Kingdom) (2006), 443 (7109), 320-323CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)The challenges assocd. with synthesizing expanded semiconductor frameworks with cage-like crystal structures continue to be of interest. Filled low-d. germanium and silicon framework structures have distinct properties that address important issues in thermoelec. phonon glass-electron crystals, supercond. and the possibility of Kondo insulators. Interest in empty framework structures of silicon and germanium is motivated by their predicted wide optical band gaps of the same magnitude as quantum dots and porous silicon, making them and their alloys promising materials for silicon-based optoelectronic devices. Although almost-empty Na1-xSi136 has already been reported, the synthesis of guest-free germanium clathrate has so far been unsuccessful. Here we report the high-yield synthesis and characteristics of germanium with the empty clathrate-II structure through the oxidn. Ge49- of Zintl anions in ionic liqs. under ambient conditions. The approach demonstrates the potential of ionic liqs. as media for the reactions of polar intermetallic phases.
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90Bentlohner, M. M.; Waibel, M.; Zeller, P.; Sarkar, K.; Müller-Buschbaum, P.; Fattakhova-Rohlfing, D.; Fässler, T. F. Zintl clusters as wet-chemical precursors for germanium nanomorphologies with tunable composition. Angew. Chem., Int. Ed. 2016, 55, 2441– 2445, DOI: 10.1002/anie.20150824690https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFGms7zE&md5=0dfeb44d88cad13ed4b31dc0e28151edZintl Clusters as Wet-Chemical Precursors for Germanium Nanomorphologies with Tunable CompositionBentlohner, Manuel M.; Waibel, Markus; Zeller, Patrick; Sarkar, Kuhu; Mueller-Buschbaum, Peter; Fattakhova-Rohlfing, Dina; Faessler, Thomas F.Angewandte Chemie, International Edition (2016), 55 (7), 2441-2445CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)[Ge9]4- Zintl clusters are used as sol. germanium source for a bottom-up fabrication of Ge nanomorphologies such as inverse opal structures with tunable compn. The method is based on the assembly and oxidn. of [Ge9]4- clusters in a template mold using SiCl4, GeCl4, and PCl3 leading to Si and P-contg. Ge phases as shown by X-ray diffraction, Raman spectroscopy, and energy-dispersive X-ray anal. [Ge9]4- clusters are retained using ethylenediamine (en) as a transfer medium to a mold after removal of the solvent if water is thoroughly excluded, but are oxidized to amorphous Ge in presence of water traces. 1H NMR spectroscopy reveals the oxidative deprotonation of en by [Ge9]4-. Subsequent annealing leads to cryst. Ge. As an example for wet-chem. synthesis of complex Ge nanomorphologies, we describe the fabrication of undoped and P-doped inverse opal-structured Ge films with a rather low oxygen contents. The morphol. of the films with regular vol. porosity is characterized by SEM, TEM, and grazing incidence small-angle X-ray scattering.
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91Goicoechea, J. M.; Sevov, S. C. Deltahedral germanium clusters: Insertion of transition-metal atoms and addition of organometallic fragments. J. Am. Chem. Soc. 2006, 128, 4155– 4161, DOI: 10.1021/ja058652g91https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XitVOjtrs%253D&md5=c2872dcd3155be1e0566d447f3e9f935Deltahedral Germanium Clusters: Insertion of Transition-Metal Atoms and Addition of Organometallic FragmentsGoicoechea, Jose M.; Sevov, Slavi C.Journal of the American Chemical Society (2006), 128 (12), 4155-4161CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Reactions of nine-atom deltahedral clusters of germanium (K4Ge9) with Ni(COD)2 and/or Ni(PPh3)2(CO)2 in ethylenediamine yielded the Ni-centered heteroat. 10-atom clusters [Ni@(Ge9Ni-CO)]2- and [Ni@(Ge9Ni-en)]3-, as well as the empty 10-atom heteroat. cluster [Ge9Ni-CO]3-. A ligand exchange reaction between [Ni@(Ge9Ni-CO)]2- and potassium phenylacetylide produced the organically functionalized species [Ni@(Ge9Ni-CCPh)]3-. The empty cluster [Ge9Ni-CO]3- is a bicapped square antiprism where one of the capping vertexes is the Ni atom. The other three clusters are tricapped trigonal prisms where an addnl. tenth vertex of mono-ligated Ni caps a triangular base of the trigonal prism. As a result of this, that base opens up, and the distances within it become nonbonding. This ensures that all atoms of the cluster are equidistant from the central Ni atom, i.e., the cluster is very close to spherical. All species were structurally characterized in cryst. compds. with [K-(2,2,2-crypt)]+ countercations. They were also characterized in soln. by mass spectrometry, IR, and 13C NMR.
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92Hlukhyy, V.; He, H.; Jantke, L. A.; Fässler, T. F. The neat ternary solid K5–xCo1–xSn9 with endohedral [Co@Sn9]5– cluster units: a precursor for soluble intermetalloid [Co2@Sn17]5– clusters. Chem. - Eur. J. 2012, 18, 12000– 12007, DOI: 10.1002/chem.20120178692https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFOmt77M&md5=a1454a67b714e9153b95c527d00dd46cThe Neat Ternary Solid K5-xCo1-xSn9 with Endohedral [Co@Sn9]5- Cluster Units: A Precursor for Soluble Intermetalloid [Co2@Sn17]5- ClustersHlukhyy, Viktor; He, Haiyan; Jantke, Laura-Alice; Faessler, Thomas F.Chemistry - A European Journal (2012), 18 (38), 12000-12007, S12000/1-S12000/10CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)A new type of Zintl phase is presented that contains endohedrally filled clusters and that allows for the formation of intermetalloid clusters in soln. by a 1-step synthesis. The intermetallic compd. K5-xCo1-xSn9 was obtained by the reaction of a preformed Co-Sn alloy with potassium and tin at high temps. The diamagnetic saltlike ternary phase contains discrete [Co@Sn9]5- clusters that are sepd. by K+ ions. The intermetallic compd. K5-xCo1-xSn9 readily and incongruently dissolves in ethylenediamine and in the presence of 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (2.2.2-crypt), thereby giving cryst. [K([2.2.2]crypt)]5[Co2Sn17]. The novel polyanion [Co2Sn17]5- contains two Co-filled Sn9 clusters that share one vertex. Both compds. were characterized by single-crystal x-ray structure anal. The diamagnetism of K5-xCo1-xSn9 and the paramagnetism of [K([2.2.2]crypt)]5[Co2Sn17] were confirmed by superconducting quantum interference device (SQUID) and EPR measurements, resp. Quantum chem. calcns. reveal an endohedral Co1- atom in an [Sn9]4- nido cluster for [Co@Sn9]5- and confirm the stability of the paramagnetic [Co2Sn17]5- unit.
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93Hlukhyy, V.; Stegmaier, S.; van Wüllen, L.; Fässler, T. F. Endohedrally filled [Ni@Sn9]4– and [Co@Sn9]5– clusters in the neat solids Na12Ni1–xSn17 and K13–xCo1–xSn17: Crystal structure and 119Sn solid-state NMR spectroscopy. Chem. - Eur. J. 2014, 20, 12157– 12164, DOI: 10.1002/chem.20140231893https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXht1GrurrL&md5=110c30035b3fa8319455c845b1f10866Endohedrally Filled [Ni@Sn9]4- and [Co@Sn9]5- Clusters in the Neat Solids Na12Ni1-xSn17 and K13-xCo1-xSn17: Crystal Structure and 119Sn Solid-State NMR SpectroscopyHlukhyy, Viktor; Stegmaier, Saskia; van Wuellen, Leo; Faessler, Thomas F.Chemistry - A European Journal (2014), 20 (38), 12157-12164CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)A systematic approach to the formation of endohedrally filled atom clusters by a high-temp. route instead of the more frequent multistep syntheses in soln. is presented. Zintl phases Na12Ni1-xSn17 and K13-xCo1-xSn17, contg. endohedrally filled intermetalloid clusters [Ni@Sn9]4- or [Co@Sn9]5- beside [Sn4]4-, were obtained from high-temp. reactions. The arrangement of [Ni@Sn9]4- or [Co@Sn9]5- and [Sn4]4- clusters, which are present in the ratio 1:2, can be regarded as a hierarchical replacement variant of the hexagonal Laves phase MgZn2 on the Mg and Zn positions, resp. The alkali-metal positions are considered for the 1st time in the hierarchical relation, which leads to a comprehensive topol. parallel and a better understanding of the compn. of these compds. The positions of the alkali-metal atoms in the title compds. are related to the known inclusion of hydrogen atoms in the voids of Laves phases. The inclusion of Co atoms in the {Sn9} cages correlates strongly with the no. of K vacancies in K13-xCo1-xSn17 and K5-xCo1-xSn9, and consequently, all compds. correspond to diamagnetic valence compds. Owing to their diamagnetism, K13-xCo1-xSn17, and K5-xCo1-xSn9, as well as the d-block metal free binary compds. K12Sn17 and K4Sn9, were characterized for the 1st time by 119Sn solid-state NMR spectroscopy.
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94Scharfe, S.; Fässler, T. F.; Stegmaier, S.; Hoffmann, S. D.; Ruhland, K. [Cu@Sn9]3– and [Cu@Pb9]3–: Intermetalloid clusters with endohedral Cu atoms in spherical environments. Chem. - Eur. J. 2008, 14, 4479– 4483, DOI: 10.1002/chem.20080042994https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmslGiurw%253D&md5=d467d904ef0e07506a4b702db7df6895[Cu@Sn9]3- and [Cu@Pb9]3-: inter-metalloid clusters with endohedral Cu atoms in spherical environmentsScharfe, Sandra; Faessler, Thomas F.; Stegmaier, Saskia; Hoffmann, Stephan D.; Ruhland, KlausChemistry - A European Journal (2008), 14 (15), 4479-4483CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The inter-metalloid clusters [K[2.2.2](crypt)]3[Cu@E9](DMF)2 (E = Sn, Pb) were prepd. and contain nine E atoms arranged to give an almost perfect sphere around a Cu atom in the endohedrally filled Zintl ions [Cu@E9]3-. The rapid equilibration of the nine Sn atoms on the spectral NMR timescale in the Sn deriv. leads to an exceptionally sharp 63Cu NMR signal. The compds. were characterized using X-ray crystallog. and NMR (copper-63, tin-119), and their electronic structure and optimized geometry were investigated using DFT calcns.
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95Jin, X.; Espinoza-Quintero, G.; Below, B.; Arcisauskaite, V.; Goicoechea, J. M.; McGrady, J. E. Structure and bonding in a bimetallic endohedral cage, [Co2@Ge16]z–. J. Organomet. Chem. 2015, 792, 149– 153, DOI: 10.1016/j.jorganchem.2015.03.03295https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmslejt7w%253D&md5=d9f577787981006f3be8c0b7322042efStructure and bonding in a bimetallic endohedral cage, [Co2@Ge16]z-Jin, Xiao; Espinoza-Quintero, Gabriela; Below, Benjamin; Arcisauskaite, Vaida; Goicoechea, Jose M.; McGrady, John E.Journal of Organometallic Chemistry (2015), 792 (), 149-153CODEN: JORCAI; ISSN:0022-328X. (Elsevier B.V.)The authors report mass spectrometric evidence for the new bimetallic cluster, [Co2@Ge16]z- which is obsd. as a mono-anion in the mass spectrum but as a tetra-anion in the solid state. D. functional theory suggests that at both oxidn. levels it adopts a D2h-sym. structure based on two pentagonal bipyramids. The 3-connected vertexes of the cage are characteristic of an electron-precise (5n = 80) count, but assigning 80 of the 86 valence electrons to the cage would imply an unrealistic degree of charge sepn. The authors resolve this dilemma by showing that many of the electron pairs fulfill a dual role, contributing to the stable 80-electron count at the cage and to the 18-electron count at each metal. Thus it is not possible in this case to partition the charge into mutually exclusive subsets on the metal and on the cluster.
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96Liu, C.; Popov, I. [Co2@Ge16]4–: Localized versus delocalized bonding in two isomeric intermetalloid clusters. Chem. - Eur. J. 2018, 24, 699, DOI: 10.1002/chem.20170444496https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFegsb%252FJ&md5=f512b5397868181bceaf02a2cc215915[Co2@Ge16]4-: Localized versus Delocalized Bonding in Two Isomeric Intermetalloid ClustersLiu, Chao; Popov, Ivan A.; Li, Lei-Jiao; Li, Ning; Boldyrev, Alexander I.; Sun, Zhong-MingChemistry - A European Journal (2018), 24 (3), 699-705CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)We report the successful isolation and structural elucidation of two bimetallic doped [Co2@Ge16]4- clusters (α and β form), which were synthesized through the reaction of [{(ArN)2CtBu}Co(η6-toluene)] (Ar=2,6-diisopropylphenyl) and K4Ge9 in ethylenediamine (en) soln. and co-crystd. together in [K(2,2,2-crypt)]4[Co2@Ge16]·en. The α-[Co2@Ge16]4- isomer prefers a distinct D2h 3-connected architecture, whereas the deltahedral isomeric β-[Co2@Ge16]4- isomer adopts a quasi-C2h geometry and can be seen as coupling of two distorted arachno-[Co@Ge10] units. Chem. bonding analyses indicate that the skeleton of the α isomer is mainly composed of localized bonds, whereas only multicenter bonding interactions govern the geometry of the β isomer, which was further found to exhibit a fluxional behavior. The coexistence of both isomers within one unit cell links the 3-connected clusters with their deltahedral congeners, thus highlighting the structural and electronic flexibility of such discreet cluster systems.
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97Sun, Z.-M.; Xiao, H.; Li, J.; Wang, L.-S. Pd2@Sn184-: Fusion of two endohedral stannaspherenes. J. Am. Chem. Soc. 2007, 129, 9560– 9561, DOI: 10.1021/ja072867497https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXnvVSiurs%253D&md5=3b7ad6523b08afcf7836ffd1e5105de6Pd2@Sn184-: Fusion of Two Endohedral StannaspherenesSun, Zhong-Ming; Xiao, Hai; Li, Jun; Wang, Lai-ShengJournal of the American Chemical Society (2007), 129 (31), 9560-9561CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Stannaspherene refers to an icosahedral 12-atom Sn cage cluster (Sn122-) and has also been found to be able to trap all transition metals to form gaseous endohedral clusters (M@Sn12-). During exploratory soln. syntheses of endohedral stannaspherenes, a new closo-deltahedral cluster, Pd2@Sn184-, has been isolated as a (2,2,2-crypt)K+ salt through the reaction of K4Sn9 and Pd[P(C6H5)3]4 in ethylenediamine solns. and characterized via X-ray crystallog. The new Pd2@Sn184- cluster has pseudo-D3d symmetry and is composed of 18 Sn atoms encapsulating two Pd atoms. It can be viewed as the fusion of two endohedral stannaspherenes (Pd@Sn122-) along their C3 axis by removing a Sn3 triangle on each Sn12 unit at the cluster-cluster interface. Electronic structure calcns. show that Pd2@Sn184- consists of a Sn184- cage with two zero-valent Pd atoms and possesses a highly stable electronic configuration.
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98Kocak, F. S.; Zavalij, P.; Lam, Y.-F.; Eichhorn, B. W. Solution dynamics and gas-phase chemistry of Pd2@Sn184–. Inorg. Chem. 2008, 47, 3515– 3520, DOI: 10.1021/ic701699d98https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXktFShsLo%253D&md5=96de2e006098fb626f29871bdf4aa4f8Solution Dynamics and Gas-Phase Chemistry of Pd2@Sn184-Kocak, F. Sanem; Zavalij, Peter; Lam, Yiu-Fai; Eichhorn, Bryan W.Inorganic Chemistry (2008), 47 (9), 3515-3520CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Sn94- reacts with Pd(PPh3)4 in ethylenediamine/toluene solvent mixts. in the presence of 2,2,2-cryptand to give the Pd2@Sn184- cluster as the K(2,2,2,-crypt)+ salt. The cluster is isostructural with Pd2@Ge184- and has a nuclearity different from that of the Pt and Ni analogs, Ni2@Sn174- and Pt2@Sn174-. The Pd2@Sn184- ion has a deltahedral capsulelike structure with 40 cluster bonding electrons and is the largest free-standing polystannide characterized to date. Like Pt2@Sn174-, the Pd2@Sn184- complex is highly dynamic in soln., showing a single 119Sn NMR resonance indicative of an intramol. liquidlike dynamic exchange. LDI-MS studies of the cryst. sample show extensive fragmentation and the formation of five gas-phase cluster series: Snx- (1 < x < 12), PdSnx-1- (4 < x < 18), Pd2Snx-2- (6 < x < 21), Pd3Snx-3- (8 < x < 21), and Pd4Snx-4- (13 < x < 21). The most abundant ion in the gas phase is the PdSn10- cluster, which presumably has an Sn10 bicapped-square-antiprismatic structure with an endohedral Pd (e.g., Ni@Pb102-).
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99Moses, M. J.; Fettinger, J. C.; Eichhorn, B. W. Interpenetrating As20 fullerene and Ni12 icosahedra in the onion-skin [As@Ni12@As20]3– ion. Science 2003, 300, 778– 780, DOI: 10.1126/science.108234299https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjtlSkt7w%253D&md5=81528139b6832b3911664fac076bb028Interpenetrating As20 Fullerene and Ni12 Icosahedra in the Onion-Skin [As@Ni12@As20]3- IonMoses, Melanie J.; Fettinger, James C.; Eichhorn, Bryan W.Science (Washington, DC, United States) (2003), 300 (5620), 778-781CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The [As@Ni12@As20]3- ion was prepd. from As73- and Ni(COD)2 in ethylenediamine solns. and isolated as the Bu4P+ salt (Bu4P)4[As@Ni12@As20]·1.5en and its crystal structure was detd. The anion contains an icosahedral [Ni12(μ12-As)]3- fragment that resides at the center of an As20 dodecahedral (fullerene) cage to give an onion-skin-like [As@Ni12@As20]3- cluster with Ih point symmetry. The icosahedron and pentagonal dodecahedron are reciprocal platonic solids, and the 32 surface atoms form a dimpled geodesic sphere composed of 60 triangular faces. In the gas phase, the [As@Ni12@As20]3- ion sequentially loses all 21 As atoms to form Ni12As21-x clusters where 0 ≤ x ≤ 21, inclusively.
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100Stegmaier, S.; Fassler, T. F. A bronze matryoshka: the discrete intermetalloid cluster [Sn@Cu12@Sn20]12- in the ternary phases A12Cu12Sn21 (A = Na, K). J. Am. Chem. Soc. 2011, 133, 19758– 19768, DOI: 10.1021/ja205934p100https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsV2ju7zF&md5=3e105eb7cf0467a7612cf3dd21e94569A Bronze Matryoshka: The Discrete Intermetalloid Cluster [Sn@Cu12@Sn20]12- in the Ternary Phases A12Cu12Sn21 (A = Na, K)Stegmaier, Saskia; Faessler, Thomas F.Journal of the American Chemical Society (2011), 133 (49), 19758-19768CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The synthesis and crystal structure of the first ternary A-Cu-Sn intermetallic phases for the heavier alkali metals A = Na to Cs is reported. The title compds. A12Cu12Sn21 show discrete 33-atom intermetalloid Cu-Sn clusters {Sn@Cu12@Sn20}, which are composed of {Sn20} pentagonal dodecahedra surrounding {Cu12} icosahedra with single Sn atoms at the center. Na12Cu12Sn21 and K12Cu12Sn21 were characterized by single-crystal XRD studies, and the successful synthesis of analogous A-Cu-Sn compds. with A = Rb and Cs is deduced from powder XRD data. The isotypic A12Cu12Sn21 phases crystallize in the cubic space group Pn‾3m, with the Cu-Sn clusters adopting a fcc. arrangement. A formal charge of 12- can be assigned to the {Sn@Cu12@Sn20} cluster unit, and the interpretation of the title compds. as salt-like intermetallic phases featuring discrete anionic intermetalloid [Sn@Cu12@Sn20]12- clusters sepd. by alkali metal cations is supported by electronic structure calcns. For both Na12Cu12Sn21 and K12Cu12Sn21, DFT band structure calcns. (TB-LMTO-ASA) reveal a band gap. The discrete [Sn@Cu12@Sn20]12- cluster is analyzed in consideration of the MOs obtained from hybrid DFT calcns. (Gaussian 09) for the cluster anion. The [Sn@Cu12@Sn20]12- cluster MOs can be classified with labels indicating the nos. of radial and angular nodes, in the style of spherical shell models of cluster bonding.
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101Wang, Y.; Moses-DeBusk, M.; Stevens, L.; Hu, J.; Zavalij, P.; Bowen, K.; Dunlap, B. I.; Glaser, E. R.; Eichhorn, B. Sb@Ni12@Sb20-/+ and Sb@Pd12@Sb20n cluster anions, where n = +1, -1, -3, -4: Multi-oxidation-state clusters of interpenetrating platonic solids. J. Am. Chem. Soc. 2017, 139, 619– 622, DOI: 10.1021/jacs.6b12109101https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFCgs7nM&md5=932f5ede463745e7f6e903a417be5f75Sb@Ni12@Sb20-/+ and Sb@Pd12@Sb20n Cluster Anions, Where n = +1, -1, -3, -4: Multi-Oxidation-State Clusters of Interpenetrating Platonic SolidsWang, Yi; Moses-DeBusk, Melanie; Stevens, Lauren; Hu, Junkai; Zavalij, Peter; Bowen, Kit; Dunlap, Brett I.; Glaser, Evan R.; Eichhorn, BryanJournal of the American Chemical Society (2017), 139 (2), 619-622CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)K5Sb4 and K3Sb7 Zintl ion precursors react with Pd(PPh3)4 in ethylenediamine/toluene/PBu4+ solns. to give crystals of Sb@Pd12@Sb20n-/PBu4+ salts, where n = 3, 4. The clusters are structurally identical in the two charge states, with nearly perfect Ih point symmetry, and can be viewed as an Sb@Pd12 icosahedron centered inside of an Sb20 dodecahedron. The metric parameters suggest very weak Sb-Sb and Pd-Pd interactions with strong radial Sb-Pd bonds between the Sb20 and Pd12 shells. All-electron DFT anal. shows the 3- ion to be diamagnetic with Ih symmetry and a 1.33 eV HOMO-LUMO gap, whereas the 4- ion undergoes a Jahn-Teller distortion to an S = 1/2 D3d structure with a small 0.1 eV gap. The distortion is predicted to be small and is not discernible by crystallog. Laser desorption-ionization time-of-flight mass spectrometry (LDI-TOF MS) studies of the cryst. samples show intense parent Sb@Pd12@Sb20- ions (neg. ion mode) and Sb@Pd12@Sb20+ (pos. ion mode) along with series of Sb@Pd12-y@Sb20-x-/+ ions. Ni(cyclooctadiene)2 reacts with K3Sb7 in en/tol/Bu4PBr solvent mixts. to give black ppts. of Sb@Ni12@Sb20n- salts that give similar Sb@Ni12@Sb20-/+ parent ions and Sb@Ni12-y@Sb20-x-/+ degrdn. series in the resp. LDI-TOF MS studies. The solid-state and gas-phase studies of the icosahedral Sb@M12@Sb20n-/n+ ions show that the clusters can exist in the -4, -3, -1, +1 (M = Pd) and +1, -1 (M = Ni) oxidn. states. These multiple-charge-state clusters are reminiscent of redox-active fullerenes (e.g., C60n, where n = +1, 0, -1, -2, -3, -4, -5, -6).
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102Li, Z.; Ruan, H.; Wang, L.; Liu, C.; Xu, L. Counterion-induced crystallization of intermetalloid Matryoshka clusters [Sb@Pd12@Sb20]3-,4-. Dalton Trans. 2017, 46, 3453– 3456, DOI: 10.1039/C7DT00342K102https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXisVGhs7s%253D&md5=9c1e4c1c5dc7c5bdb5cc2cecacfd7812Counterion-induced crystallization of intermetalloid Matryoshka clusters [Sb@Pd12@Sb20]3-,4-Li, Zhenyu; Ruan, Huapeng; Wang, Lulu; Liu, Caiping; Xu, LiDalton Transactions (2017), 46 (11), 3453-3456CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)Two intermetalloid Matryoshka cluster anions [Sb@Pd12@Sb20]3-,4- obtained from the reaction of KSb and Pd(PPh3)4 were isolated as [K(2,2,2-cryptand)]+ and [K(18-crown-6)]+ salt, resp., and characterized by x-ray crystallog., EPR measurement and DFT theor. calcns.
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103Adamo, C.; Barone, V. Toward reliable density functional methods without adjustable parameters: The PBE0 model. J. Chem. Phys. 1999, 110, 6158– 6170, DOI: 10.1063/1.478522103https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXitVCmt7Y%253D&md5=cad4185c69f9232753497f5203d6dc9fToward reliable density functional methods without adjustable parameters: the PBE0 modelAdamo, Carlo; Barone, VincenzoJournal of Chemical Physics (1999), 110 (13), 6158-6170CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We present an anal. of the performances of a parameter free d. functional model (PBE0) obtained combining the so called PBE generalized gradient functional with a predefined amt. of exact exchange. The results obtained for structural, thermodn., kinetic and spectroscopic (magnetic, IR and electronic) properties are satisfactory and not far from those delivered by the most reliable functionals including heavy parameterization. The way in which the functional is derived and the lack of empirical parameters fitted to specific properties make the PBE0 model a widely applicable method for both quantum chem. and condensed matter physics.
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104Bruna, P. J.; Wright, J. S. Theoretical study of the ionization potentials of boron dimer. J. Phys. Chem. 1990, 94, 1774– 1781, DOI: 10.1021/j100368a014104https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXht1Gmtr4%253D&md5=d6f2f74cb8fd2a0e4e619542578ba862Theoretical study of the ionization potentials of boron dimerBruna, Pablo J.; Wright, James S.Journal of Physical Chemistry (1990), 94 (5), 1774-81CODEN: JPCHAX; ISSN:0022-3654.Extensive MRD-CI calcns. carried out with a contracted 6s5p2d1f Gaussian basis set indicate that B2+ has a X2Σg+ (σg2σu2σ9) ground and a low-lying I2Πu(σg2σu2πu) state (Te = 0.25 eV). The computed dissocn. energies De are 1.90 eV for X2Σg+ and 1.65 eV for 12Πu. The adiabatic ionization potentials (IP) of B2 from X3Σg3(σg2σu2πu2) into X2Σg+(πu2 → σg,∞) and into 1iΠu(πu → ∞) are 8.99 and 9.24 eV, resp.; both results are expected to underestimate the true values by about 0.15 eV. The present data do not support recent exptl. and ab initio results from Hanley, et al., (1988). Those authors reported a 2Πu ground state, with a De of 0.8 ± 0.6 eV (0.7 eV) and an adiabatic IP (X3Σg- → 2Πu) of 10.3 eV (8.9 eV), with values in parentheses corresponding to their ab initio results. Since the photoelectron spectrum of B2 (not yet recorded to our knowledge) represents a valuable and alternative exptl. technique for the spectroscopic characterization of low-lying states of B2+, the IP's are investigated here for one-electron ionization processes having X3Σg-, 15Σu-, and 13Πu of B2 as lower state. The corresponding Franck-Condon factors are also reported.
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105Rohlfing, C. M.; Martin, R. L. A theoretical study of the isovalent diatomics carbon dimer, silicon dimer, and silicon monocarbide. J. Phys. Chem. 1986, 90, 2043– 2046, DOI: 10.1021/j100401a014105https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XhvFGls7k%253D&md5=fe61f1206f7ba72981dba3689175854fA theoretical study of the isovalent diatomics carbon dimer, silicon dimer, and silicon monocarbideRohlfing, Celeste McMichael; Martin, Richard L.Journal of Physical Chemistry (1986), 90 (10), 2043-6CODEN: JPCHAX; ISSN:0022-3654.Ab initio calcns. on the mols. C2, Si2, and SiC are performed to det. equil. geometries (Re) and spectroscopic consts. (ωe, ωexi, and Ee) for various electronic states. A large basis set including 2 d functions on each atom is used, and electron correlation is treated by 2 different methods. The 1st approach is that of Moeller-Plesset perturbation theory based on a UHF ref. function. The 2nd approach is that of externally contracted CI based on a multireference function of the complete-active-space type. Good agreement between theory and expt. is achieved for the homonuclear diatomics. The best theor. value obtained for the ground-state harmonic frequency ωe of SiC is 940 cm-1. After consideration of the remaining basis set and correlation effects, an est. of 975 ± 10 cm-1 is made for ωe in the unobserved mol. SiC. Finally, a comparison is made between the 2 theor. approaches used in this study.
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106Bauschlicher, C. W., Jr; Barnes, L. A.; Taylor, P. R. Lowest ionization potentials of aluminum dimer. J. Phys. Chem. 1989, 93, 2932– 2935, DOI: 10.1021/j100345a017106https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXhs1Slt7c%253D&md5=e7639d9966abd60497f5c7b830171cceLowest ionization potentials of aluminum dimerBauschlicher, Charles W., Jr.; Barnes, Leslie A.; Taylor, Peter R.Journal of Physical Chemistry (1989), 93 (8), 2932-5CODEN: JPCHAX; ISSN:0022-3654.Potential curves for the lowest two electronic states (X2Σg+ and A2Πu) of Al2+ have been computed by using complete active space SCF/multireference CI wave functions and large Gaussian basis sets. The lowest observable vertical ionization potential (to Al2+ X2Σg+) of the Al2 X3Πu ground state is calcd. to occur around 6.1 eV, in excellent agreement with the exptl. range of 6.0-6.42 eV obtained in recent cluster ionization studies by Cox and co-workers. The second vertical ionization potential (to Al2+ A2Πu) occurs near 6.4 eV, also within the exptl. range. The adiabatic ionization potential of 5.90 eV is in good agreement with the value of 5.8-6.1 eV deduced by Hanley and co-workers from the difference in thresholds between collision-induced dissocn. processes of Al3+. The computed ionization potential values are somewhat larger than those deduced from branching ratio sin cluster fragmentation expts. by Jarroled and wo-workers. The observation of an ionization threshold below 6.42 eV is shown to be incompatible with an Al2 ground electronic state assignment of 3Σg-, but the sepn. between the two lowest states of Al2 is so small that it is likely that both are populated in the expts., so that this does not provide unambiguous support for the recent theor. assignment of the ground state as 3Πu.
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107Huber, K.-P.; Herzberg, G. Constants of diatomic molecules; Van Nostrand Reinhold Company: New York, 1979.There is no corresponding record for this reference.
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108Pacchioni, G. On the ground-state properties of the germanium dimer. Chem. Phys. Lett. 1984, 107, 70– 71, DOI: 10.1016/0009-2614(84)85358-0108https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXkt1ylsrc%253D&md5=055c77a6efc57055d45339954c61c367On the ground-state properties of the germanium dimerPacchioni, GianfrancoChemical Physics Letters (1984), 107 (1), 70-1CODEN: CHPLBC; ISSN:0009-2614.The bond length, vibrational frequency, and dissocn. energy of the Ge2 mol. were calcd. Effective-core-potential Hartree-Fock calcns. followed by extensive CI gave Re = 4.60 bohr, ωe = 217 cm-1, De = 2.54 eV. These values are discussed and compared with those of previous theor. work and with the available exptl. data.
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109Ho, J.; Polak, M. L.; Ervin, K. M.; Lineberger, W. C. Photoelectron spectroscopy of nickel group dimers: Ni2, Pd2, and Pt2. J. Chem. Phys. 1993, 99, 8542– 8551, DOI: 10.1063/1.465577109https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsVOktb4%253D&md5=4e58af3b448827ae92cbf6489a1198c6Photoelectron spectroscopy of nickel group dimers: the nickel palladium, and platinum diatomic mononegative ions (Ni2-, Pd2-, and Pt2-)Ho, Joe; Polak, Mark L.; Ervin, Kent M.; Lineberger, W. C.Journal of Chemical Physics (1993), 99 (11), 8542-51CODEN: JCPSA6; ISSN:0021-9606.Neg. ion photoelectron spectra of Ni2-, Pd2-, Pt2- are presented for electron binding energies up to 3.35 eV at an instrumental resoln. of 8-10 meV. The metal cluster anions are prepd. in a flowing afterglow ion source. Each dimer exhibits multiple low-lying electronic states and a vibrationally resolved ground state transition. Franck-Condon analyses yielded the anion and neutral vibrational frequencies and the bond length changes between anion and neutral. The electron affinities are detd. to be EA (Ni2) = 0.926 ± 0.010 eV, EA (Pd2) = 1.685 ± 0.008 eV, and EA (Pt2) = 1.898 ± 0.008 eV. The electronic configurations of the ground states are tentatively assigned. Comparison of the nickel group dimers to the coinage metal dimers sheds light on the d orbital contribution to the metal bonding in the nickel group dimers.
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110Ghosh, A.; Chaudhuri, R. K.; Chattopadhyay, S. Relativistic state-specific multireference coupled cluster theory description for bond-breaking energy surfaces. J. Chem. Phys. 2016, 145, 124303, DOI: 10.1063/1.4962911110https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsFOmsr3O&md5=bf91a14bb5032913b1e7c40769edf7a2Relativistic state-specific multireference coupled cluster theory description for bond-breaking energy surfacesGhosh, Anirban; Chaudhuri, Rajat K.; Chattopadhyay, SudipJournal of Chemical Physics (2016), 145 (12), 124303/1-124303/15CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A four-component (4c) relativistic state specific multireference coupled cluster (4c-SSMRCC) method has been developed and applied to compute the ground state spectroscopic consts. of Ag2, Cu2, Au2, and I2. The ref. functions used in these calcns. are obtained using computationally inexpensive improved virtual orbital-complete active space CI scheme. Rigorous size-extensivity and insensitivity towards the intruder state problem make our method an interesting choice for the calcn. of the dissocn. energy surface. To the best of our knowledge, this study is the first implementation of the SSMRCC within the relativistic framework. The overall agreement of our results, employing the smallest model space, with both theor. and exptl. ref. values indicates that the 4c-SSMRCC method can be fruitfully used to describe electronic structures and assocd. properties of systems contg. heavy elements. We observe a relativistic bond stabilization for the coinage metal dimers while the I-I bond is weakened by the relativistic effects. (c) 2016 American Institute of Physics.
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111Suzumura, T.; Nakajima, T.; Hirao, K. Ground-stale properties of MH, MCl, and M2 (M = Cu, Ag, and Au) calculated by a scalar relativistic density functional theory. Int. J. Quantum Chem. 1999, 75, 757– 766, DOI: 10.1002/(SICI)1097-461X(1999)75:4/5<757::AID-QUA42>3.0.CO;2-R111https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXntlyksrw%253D&md5=d91c1f41716c5b75ecb580e6ac71e981Ground-state properties of MH, MCl, and M2 (M = Cu, Ag, and Au) calculated by a scalar relativistic density functional theorySuzumura, Toshihisa; Nakajima, Takahito; Hirao, KimihikoInternational Journal of Quantum Chemistry (1999), 75 (4/5), 757-766CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)The effects of relativity on the bond lengths, vibrational frequencies, dissocn. energies, and dipole moments of the ground states of the group IB hydrides MH, chlorides MCl, and dimers M2 (M = Cu, Ag, and Au) have been studied by relativistic d. functional theory (DFT) with the B88 plus one-parameter progressive (BOP) exchange-correlation functional. The relativistic effects were included through a scalar relativistic scheme by the elimination of the small components (RESC) of the four-component Dirac spinors. Comparisons were made between all-electron results using the nonrelativistic Hamiltonian, results with quasi-relativistic effective core potentials (ECP), and results with a spin-free RESC scheme. The RESC approach clearly works very well. The bond distances, vibrational frequencies, and dissocn. energies show good agreement with the expt. The expected trends of bond length decrease, harmonic vibrational frequency increase, and dipole moment decrease with relativity are found. Although the dissocn. energy increases with the relativity for hydrides and dimers, the reverse trend is obsd. for chlorides. A quasi-relativistic ECP also works well for hydrides. However, ECP gives a rather poor description for chlorides and dimers.
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112Miralrio, A.; Sansores, L. E. On the search of stable, aromatic and ionic endohedral compounds of C28: A theoretical study. Comput. Theor. Chem. 2016, 1083, 53– 63, DOI: 10.1016/j.comptc.2016.03.010112https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XksFKktLY%253D&md5=457166fa9aa2bec6324575f7cc01eff1On the search of stable, aromatic and ionic endohedral compounds of C28: A theoretical studyMiralrio, Alan; Sansores, Luis EnriqueComputational & Theoretical Chemistry (2016), 1083 (), 53-63CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The X@C28 compds. form the family of the smallest endohedral fullerenes. Currently, they consist of C28, which is endohedrally doped with group-4 elements (Ti, Zr, Hf) and U. We have studied the electronic properties, equil. geometries, binding energies and other properties of several X@C28 at the PBE/def2-TZVP level. These were compared with the tetraanion C4-28. For this study we have chosen elements from groups 4, 14 and Sc as endohedral dopants for being many of them tetravalent. In addn., we studied by the first time the entire group-10 (Ni, Pd and Pt) as endohedral dopant of C28. To elucidate the stability of these ionic compds., we have studied their binding energies. Our results show that a big pos. binding energy is necessary but not enough to det. the stability of these endohedral fullerenes. We propose that a HOMO-LUMO gap around 2 eV results in less reactive compds., property only shown by group-4 compds. Some compds. have arom. character in all rings according with their NICS(0)iso and reparametrized HOMA indexes. In addn., the charge distribution have been studied with NBO and Hirshfeld population anal. as well as electrostatic potential maps in order to find similarities between them and that shown by the tetraanion C4-28. The most stable compds. are the group-4 X@C28 which form compds.: energetically favorable, less reactive, ionic and arom. Our results are compared with available exptl. information about the formation of these compds.
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113Chase, B.; Herron, N.; Holler, E. Vibrational spectroscopy of fullerenes (C60 and C70). Temperature dependant studies. J. Phys. Chem. 1992, 96, 4262– 4266, DOI: 10.1021/j100190a029113https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XisVCjtro%253D&md5=3053f64f8562419b6f032b810166da38Vibrational spectroscopy of fullerenes (C60 and C70). Temperature dependant studiesChase, Bruce; Herron, Norm; Holler, EddJournal of Physical Chemistry (1992), 96 (11), 4262-6CODEN: JPCHAX; ISSN:0022-3654.The Fourier-transform (FT)-Raman and FTIR spectra of C60 and C70 were obtained under high resoln. conditions, both for solid material and in soln. The very small differences in frequency and line width for soln. and solid-state spectra are interpreted in terms of minimal intermol. interactions. The temp. dependence of the IR modes shows a phase transition near 260 K, in agreement with x-ray results. Below the phase transition temp., fine structure develops on several of the IR modes, indicative of an increase in solid-state interactions.
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114Wu, X.; Liang, X.; Du, Q.; Zhao, J.; Chen, M.; Lin, M.; Wang, J.; Yin, G.; Ma, L.; King, R. B. Medium-sized (n = 14–20) clusters: a combined study of photoelectron spectroscopy and DFT calculations. J. Phys.: Condens. Matter 2018, 30, 354002, DOI: 10.1088/1361-648X/aad65a114https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvFKrtLvO&md5=4fb4dba4acd6c10c3a8a24c1357e806bMedium-sized Sin- (n = 14-20) clusters: a combined study of photoelectron spectroscopy and DFT calculationsWu, Xue; Liang, Xiaoqing; Du, Qiuying; Zhao, Jijun; Chen, Maodu; Lin, Miao; Wang, Jiashuai; Yin, Guangjia; Ma, Lei; King, R. Bruce; von Issendorff, BerndJournal of Physics: Condensed Matter (2018), 30 (35), 354002/1-354002/10CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Size-selected anionic silicon clusters, Sin- (n = 14-20), have been investigated by photoelectron spectroscopy and d. functional theory (DFT) calcns. Low-energy structures of the clusters are globally searched for by using a genetic algorithm based on DFT calcns. The electronic d. of states and vertical detachment energies have been simulated by using ten DFT functionals and compared to the exptl. results. We systematically evaluated the DFT functionals for the calcn. of the energetics of silicon clusters. CCSD(T) single-point energies based on MP2 optimized geometries for selected isomers of Sin- are also used as benchmark for the energy sequence. The HSE06 functional with aug-cc-pVDZ basis set is found to show the best performance. Our global min. search corroborates that most of the lowest-energy structures of Sin- (n = 14-20) clusters can be derived from assembling tricapped trigonal prisms in various ways. For most sizes previous structures are confirmed, whereas for Si20- a new structure has been found.
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115Zhao, J.; Huang, X.; Shi, R.; Liu, H.; Su, Y.; King, R. B. B28: The smallest all-boron cage from an ab initio global search. Nanoscale 2015, 7, 15086– 15090, DOI: 10.1039/C5NR04034E115https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlynsbzO&md5=32e05d6342b9a0da1fbb5be7e000fdd6B28: the smallest all-boron cage from an ab initio global searchZhao, Jijun; Huang, Xiaoming; Shi, Ruili; Liu, Hongsheng; Su, Yan; King, R. BruceNanoscale (2015), 7 (37), 15086-15090CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Our ab initio global searches reveal the lowest-energy cage for B28, which is built from two B12 units and prevails over the competing structural isomers such as planar, bowl, and tube. This smallest boron cage extends the scope of all-boron fullerene and provides a new structural motif of boron clusters and nanostructures.
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116Li, F.; Jin, P.; Jiang, D.-e.; Wang, L.; Zhang, S. B.; Zhao, J.; Chen, Z. B80 and B101–103 clusters: Remarkable stability of the core-shell structures established by validated density functionals. J. Chem. Phys. 2012, 136, 074302, DOI: 10.1063/1.3682776116https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XitlWmsbo%253D&md5=46fdb8f28ac0c4e3e42ac881eb8c35d4B80 and B101-103 clusters: Remarkable stability of the core-shell structures established by validated density functionalsLi, Fengyu; Jin, Peng; Jiang, De-en; Wang, Lu; Zhang, Shengbai B.; Zhao, Jijun; Chen, ZhongfangJournal of Chemical Physics (2012), 136 (7), 074302/1-074302/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Prompted by the very recent claim that the volleyball-shaped B80 fullerene is lower in energy than the B80 buckyball and core-shell structure, and inspired by the most recent finding of another core-shell isomer as the lowest energy B80 isomer, we carefully evaluated the performance of the d. functional methods in the energetics of boron clusters and confirmed that the core-shell construction (stuffed fullerene) is thermodynamically the most favorable structural pattern for B80. Our global min. search showed that both B101 and B103 also prefer a core-shell structure and that B103 can reach the complete core-shell configuration. We called for great attention to the theor. community when using d. functionals to investigate boron-related nanomaterials. (c) 2012 American Institute of Physics.
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117Olejniczak, A.; Cichy, B.; Stręk, W. DFT calculations of metal-organic I-III-VI semiconductor clusters: Benchmark of exchange-correlation functionals and localized basis sets. Comput. Mater. Sci. 2019, 163, 186– 195, DOI: 10.1016/j.commatsci.2019.03.036117https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlvFeksb4%253D&md5=ecd242602a277e38581361e9ec0b9cdbDFT calculations of metal-organic I-III-VI semiconductor clusters: Benchmark of exchange-correlation functionals and localized basis setsOlejniczak, Adam; Cichy, Bartlomiej; Strek, WieslawComputational Materials Science (2019), 163 (), 186-195CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)The primary objective of this work was to find the numerical methods suitable for DFT calcns. of ternary I-III-VI semiconductor quantum dots emerging as new functional materials which demonstrate an increasing need to comprehend their complex physicochem. properties. The benchmarking anal. of 8 exchange-correlation functionals and 11 basis sets including all-electron and effective core potential ones was performed. Four metal-org. mols., widely used as a single-precursor in the synthesis of A-In-X2 semiconductor quantum dots (A = Cu, Ag; X = S, Se) were considered as simple representatives of ternary semiconductor quantum dots. The geometrical parameters of the optimized structures were compared to the X-ray diffraction data. The hybrid PBE0 and B3PW91 functionals were found to be the best performing methods esp. when connected with cc-PVDZ or Def2-SVP basis sets. The methods widely used in the previous calcns. of II-VI semiconductor quantum dots, namely B3LYP functional and LANL2DZ or SBKJC basis sets, in this case resulted in lower agreement with the exptl. data.
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118Lousada, C. M.; Johansson, A. J.; Brinck, T.; Jonsson, M. Reactivity of metal oxide clusters with hydrogen peroxide and water–a DFT study evaluating the performance of different exchange–correlation functionals. Phys. Chem. Chem. Phys. 2013, 15, 5539– 5552, DOI: 10.1039/c3cp44559c118https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXkt1Gnsrw%253D&md5=aae4ff6dd76e2c755a726dd9bbf6c2f0Reactivity of metal oxide clusters with hydrogen peroxide and water - a DFT study evaluating the performance of different exchange-correlation functionalsLousada, Claudio M.; Johansson, Adam Johannes; Brinck, Tore; Jonsson, MatsPhysical Chemistry Chemical Physics (2013), 15 (15), 5539-5552CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We have performed a d. functional theory (DFT) investigation of the interactions of H2O2, H2O and HO radicals with clusters of ZrO2, TiO2 and Y2O3. Different modes of H2O adsorption onto the clusters were studied. In almost all the cases the dissociative adsorption is more exothermic than mol. adsorption. At the surfaces where H2O has undergone dissociative adsorption, the adsorption of H2O2 and the transition state for its decompn. are mediated by hydrogen bonding with the surface HO groups. Using the functionals B3LYP, B3LYP-D and M06 with clusters of 26 and 8 units of ZrO2, the M06 functional performed better than B3LYP in describing the reaction of decompn. of H2O2 and the adsorption of H2O. Addnl., we investigated clusters of the type (ZrO2)2, (TiO2)2 and (Y2O3) and the performance of the functionals B3LYP, B3LYP-D, B3LYP*, M06, M06-L, PBE0, PBE and PWPW91 in describing H2O2, H2O and HO√ adsorption and the energy barrier for decompn. of H2O2. The trends obtained for HO√ adsorption onto the clusters are discussed in terms of the ionization energy of the metal cation present in the oxide. In order to correctly account for the existence of an energy barrier for the decompn. of H2O2, the functional used must include Hartree-Fock exchange. Using minimal cluster models, the best performance in describing the energy barrier for H2O2 decompn. was obtained with the M06 and PBE0 functionals - the av. abs. deviations from expts. are 6 kJ mol-1 and 5 kJ mol-1 resp. With the M06 functional and a larger monoclinic (ZrO2)8 cluster model, the performance is in excellent agreement with exptl. data. For the different oxides, PBE0 was found to be the most effective functional in terms of performance and computational time cost.
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119Guo, L.; Zheng, X.; Zeng, Z.; Zhang, C. Spin orbital effect in lanthanides doped silicon cage clusters. Chem. Phys. Lett. 2012, 550, 134– 137, DOI: 10.1016/j.cplett.2012.08.076119https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVals7vL&md5=47c842c2b39fee40f5f7d24259ed539dSpin orbital effect in lanthanides doped silicon cage clustersGuo, Lingju; Zheng, Xiaohong; Zeng, Z.; Zhang, ChaoChemical Physics Letters (2012), 550 (), 134-137CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The stability of lanthanides (Ln) doped silicon cage clusters Ln@Si16 was studied using the DFT-PBE method. Fullerene-like Ln@Si16 structures are always more stable than Frank-Kasper structures, in contrast to transition metal doped Si16 clusters. By taking into account the spin-orbital coupling (SOC), some of the Ln@Si16 clusters show large total magnetic moments. The clusters with Pr, Nd, Sm and Tm have large orbital moments. The spin-orbit coupling effect may give useful information for further Stern-Gerlach magnetic deflection expts. and theor. simulations.
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120Li, T.; Feng, Z.; Jing, C.; Hong, F.; Cao, S.; Zhang, J. Importance of spin–orbit coupling in M@Pb12 clusters (M = 3d and 4d atoms).. Chem. Phys. Lett. 2012, 543, 106– 110, DOI: 10.1016/j.cplett.2012.06.034120https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFSrur3F&md5=c8f446cf785e1d2705407a7a3e907487Importance of spin-orbit coupling in M@Pb12 clusters (M = 3d and 4d atoms)Li, Tongwei; Feng, Zhenjie; Jing, Chao; Hong, Feng; Cao, Shixun; Zhang, JincangChemical Physics Letters (2012), 543 (), 106-110CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We investigated the effect of spin-orbit coupling (SOC) on symmetry and magnetism of M@Pb12 clusters (M = 3d and 4d transition-metal atoms) using the DFT-PBE method. The symmetry of geometrical configurations may be enhanced with SOC. The SOC marginally affects the local spin magnetic moments of 3d atoms encapsulated in the Pb12 cages, whereas for 4d series, the spin moments of most impurities will remarkably decrease when SOC is considered due to the strong hybridization between M-4d and Pb-6p states. The considerable orbital moments can be obtained. The variation trend of orbital moments can well be explained based on Hund's rule.
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121Sargolzaei, M.; Lotfizadeh, N. Spin and orbital magnetism of a single 3d transition-metal atom doped into icosahedral coinage-metal clusters X12 (X = Cu, Ag, Au). Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 83, 155404, DOI: 10.1103/PhysRevB.83.155404121https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXlsVynurw%253D&md5=38987f99a4b655d0d52fe4392707dacbSpin and orbital magnetism of a single 3d transition-metal atom doped into icosahedral coinage-metal clusters X12 (X=Cu, Ag, Au)Sargolzaei, Mahdi; Lotfizadeh, NedaPhysical Review B: Condensed Matter and Materials Physics (2011), 83 (15), 155404/1-155404/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors demonstrated the electronic structures and magnetic properties of single 3d transition metal (TM) atoms encapsulated in noble metal clusters with icosahedral symmetry in the framework of relativistic d. functional theory. Orbital polarization corrections were used to obtain an upper-estn. for orbital magnetic moments of all individual 3d atoms. The relativistic corrections are marginally affected the spin magnetic moments, whereas they induce significant orbital magnetism in TM@X12 icosahedra. A superat. picture has to be taken into account to explain the spin and orbital magnetism induced in TM@X12 icosahedron based on the Hund's rules.
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122Wales, D. J.; Doye, J. P. Global optimization by basin-hopping and the lowest energy structures of Lennard-Jones clusters containing up to 110 atoms. J. Phys. Chem. A 1997, 101, 5111– 5116, DOI: 10.1021/jp970984n122https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXktVGrurY%253D&md5=f40693ff24b5c84a8c482fa18ec1eb47Global Optimization by Basin-Hopping and the Lowest Energy Structures of Lennard-Jones Clusters Containing up to 110 AtomsWales, David J.; Doye, Jonathan P. K.Journal of Physical Chemistry A (1997), 101 (28), 5111-5116CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We describe a global optimization technique using "basin-hopping" in which the potential energy surface is transformed into a collection of interpenetrating staircases. This method has been designed to exploit the features that recent work suggests must be present in an energy landscape for efficient relaxation to the global min. The transformation assocs. any point in configuration space with the local min. obtained by a geometry optimization started from that point, effectively removing transition state regions from the problem. However, unlike other methods based upon hypersurface deformation, this transformation does not change the global min. The lowest known structures are located for all Lennard-Jones clusters up to 110 atoms, including a no. that have never been found before in unbiased searches.
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123Goedecker, S. Minima hopping: An efficient search method for the global minimum of the potential energy surface of complex molecular systems. J. Chem. Phys. 2004, 120, 9911– 9917, DOI: 10.1063/1.1724816123https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXktVehs7g%253D&md5=de03d696276ea3d433443c3139a674dfMinima hopping: An efficient search method for the global minimum of the potential energy surface of complex molecular systemsGoedecker, StefanJournal of Chemical Physics (2004), 120 (21), 9911-9917CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A method is presented that can find the global min. of very complex condensed matter systems. It is based on the simple principle of exploring the configurational space as fast as possible and of avoiding revisiting known parts of this space. Even though it is not a genetic algorithm, it is not based on thermodn. The efficiency of the method depends strongly on the type of moves that are used to hop into new local min. Moves that find low-barrier escape-paths out of the present min. generally lead into low energy min.
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124Heiles, S.; Johnston, R. L. Global optimization of clusters using electronic structure methods. Int. J. Quantum Chem. 2013, 113, 2091– 2109, DOI: 10.1002/qua.24462124https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnvVSiu7Y%253D&md5=91e62cbdee6f4d00a7d1e6ffa6315040Global optimization of clusters using electronic structure methodsHeiles, Sven; Johnston, Roy L.International Journal of Quantum Chemistry (2013), 113 (18), 2091-2109CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)A review. Over the past decade, there has been a significant growth in the development and application of methods for performing global optimization (GO) of cluster and nanoparticle structures using first-principles electronic structure methods coupled to sophisticated search algorithms. This has in part been driven by the desire to avoid the use of empirical potentials (EPs), esp. in cases where no reliable potentials exist to guide the search toward reasonable regions of configuration space. This has been facilitated by improvements in the reliability of the search algorithms, increased efficiency of the electronic structure methods, and the development of faster, multiprocessor high-performance computing architectures. In this review, we give a brief overview of GO algorithms, though concg. mainly on genetic algorithm and basin hopping techniques, first in combination with EPs. The major part of the review then deals with details of the implementation and application of these search methods to allow exploration for global min. cluster structures directly using electronic structure methods and, in particular, d. functional theory. Example applications are presented, ranging from isolated monometallic and bimetallic clusters to mol. clusters and ligated and surface supported metal clusters. Finally, some possible future developments are highlighted. © 2013 Wiley Periodicals, Inc.
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125Lyakhov, A. O.; Oganov, A. R.; Stokes, H. T.; Zhu, Q. New developments in evolutionary structure prediction algorithm USPEX. Comput. Phys. Commun. 2013, 184, 1172– 1182, DOI: 10.1016/j.cpc.2012.12.009125https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltlWgtg%253D%253D&md5=2e23099cbaa30f13f2c15bad849e144bNew developments in evolutionary structure prediction algorithm USPEXLyakhov, Andriy O.; Oganov, Artem R.; Stokes, Harold T.; Zhu, QiangComputer Physics Communications (2013), 184 (4), 1172-1182CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier B.V.)The authors present new developments of the evolutionary algorithm USPEX for crystal structure prediction and its adaptation to cluster structure prediction. To generate randomly sym. structures, and to introduce 'smart' variation operators, learning about preferable local environments. These and other developments substantially improve the efficiency of the algorithm and allow reliable prediction of structures with up to ∼200 atoms in the unit cell. An advanced version of the Particle Swarm Optimization (PSO) can be created from the authors' method, but PSO is strongly outperformed by USPEX. Also ideas from metadynamics can be used in the context of evolutionary structure prediction for escaping from local min. The authors' cluster structure prediction algorithm, using the ideas initially developed for crystals, also shows excellent performance and outperforms other state-of-the-art algorithms.
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126Zhao, J. J.; Shi, R. L.; Sai, L. W.; Huang, X. M.; Su, Y. Comprehensive genetic algorithm for ab initio global optimisation of clusters. Mol. Simul. 2016, 42, 809– 819, DOI: 10.1080/08927022.2015.1121386126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XlsFOntrY%253D&md5=e44ea50c1dd62073a1bd62a9858265b6Comprehensive genetic algorithm for ab initio global optimisation of clustersZhao, Jijun; Shi, Ruili; Sai, Linwei; Huang, Xiaoming; Su, YanMolecular Simulation (2016), 42 (10), 809-819CODEN: MOSIEA; ISSN:0892-7022. (Taylor & Francis Ltd.)A review. Cluster, as the aggregate of a few to thousands of atoms or mols., bridges the microscopic world of atoms and mols. and the macroscopic world of condensed matters. The phys. and chem. properties of a cluster are detd. by its ground state structure, which is significantly different from its bulk structure and sensitively relies on the cluster size. As a well-known nondeterministic polynomial-time hard problem, detg. the ground state structure of a cluster is a challenging task due to the extreme complexity of high-dimensional potential energy surface (PES). Genetic algorithm (GA) is an efficient global optimization method to explore the PES of clusters. Recently, we have developed a GA-based program, namely comprehensive genetic algorithm (CGA), and incorporated it with ab initio calcns. Using this program, the lowest energy structures of a variety of elemental and compd. clusters with different types of chem. bonding have been detd., and their phys. properties have been investigated and compared with exptl. data. In this article, we will describe the technique details of CGA program and present an overview of its successful applications.
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127Shang, C.; Liu, Z.-P. Stochastic surface walking method for structure prediction and pathway searching. J. Chem. Theory Comput. 2013, 9, 1838– 1845, DOI: 10.1021/ct301010b127https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFOlt7c%253D&md5=ff2585b886e8cc63d4443934f5317048Stochastic Surface Walking Method for Structure Prediction and Pathway SearchingShang, Cheng; Liu, Zhi-PanJournal of Chemical Theory and Computation (2013), 9 (3), 1838-1845CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)We propose an unbiased general-purpose potential energy surface (PES) searching method for both the structure and the pathway prediction of a complex system. The method is based on the idea of bias-potential-driven dynamics and Metropolis Monte Carlo. A central feature of the method is able to perturb smoothly a structural configuration toward a new configuration and simultaneously has the ability to surmount the high barrier in the path. We apply the method for locating the global min. (GM) of short-ranged Morse clusters up to 103 atoms starting from a random structure without using extra information from the system. In addn. to GM searching, the method can identify the pathways for chem. reactions with large dimensionality, as demonstrated in a nanohelix transformation contg. 222 degrees of freedoms.
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128Lv, J.; Wang, Y.; Zhu, L.; Ma, Y. Particle-swarm structure prediction on clusters. J. Chem. Phys. 2012, 137, 084104, DOI: 10.1063/1.4746757128https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xht1CgtLzP&md5=8a1a3cd99ae1c2bec4f2d258d509c253Particle-swarm structure prediction on clustersLv, Jian; Wang, Yanchao; Zhu, Li; Ma, YanmingJournal of Chemical Physics (2012), 137 (8), 084104/1-084104/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We developed an efficient method for cluster structure prediction based on the generalization of particle swarm optimization (PSO). A local version of PSO algorithm was implemented to utilize a fine exploration of potential energy surface for a given non-periodic system. We specifically devised a technique of so-called bond characterization matrix (BCM) to allow the proper measure on the structural similarity. The BCM technique was then employed to eliminate similar structures and define the desirable local search spaces. The introduction of point group symmetries into generation of cluster structures enables structural diversity and apparently avoids the generation of liq.-like (or disordered) clusters for large systems, thus considerably improving the structural search efficiency. We incorporated Metropolis criterion into our method to further enhance the structural evolution towards low-energy regimes of potential energy surfaces. Our method was extensively benchmarked on Lennard-Jones clusters with different sizes up to 150 atoms and applied into prediction of new structures of medium-sized Lin (n = 20, 40, 58) clusters. High search efficiency was achieved, demonstrating the reliability of the current methodol. and its promise as a major method on cluster structure prediction. (c) 2012 American Institute of Physics.
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129Lewis, G. N. The atom and the molecule. J. Am. Chem. Soc. 1916, 38, 762– 785, DOI: 10.1021/ja02261a002129https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaC28XlvFSl&md5=9f8b4fdf6c255a1c60dafaad766c9d3aThe atom and the moleculeLewis, G. N.Journal of the American Chemical Society (1916), 38 (), 762-85CODEN: JACSAT; ISSN:0002-7863.cf. C. A. 71 3865 and Bray and Branch, C. A. 7, 3865. Compds. should be classed as polar and nonpolar rather than inorg. and org. These classes are roughly the same. A nonpolar mol. is one in which the electrons belonging to the individual atom are held by such restraints that they do not move far from their normal positions, while in the polar mols. the electrons, being more mobile, so move as to sep. the mol. into positive and negative parts. In an extremely polar mol. such as NaCl it is probable that in the great majority of the mols. the Cl atom has acquired a unit negative charge and therefore the Na atom a unit positive charge, and the process of ionization probably consists only in a further sepn. of these charged parts. If a weakly polar mol. comes into the neighborhood of a more polar one it becomes itself more polar. In this process the weaker bipole stretches and its moment increases. A "cubical atom" is proposed as a basis of a new theory of atomic structure. Thus Li is a cube with a single electron on one corner, Be has 2 electrons, B 3, C 4, N 5, O 6, and F 7. This view is in harmony with the theory developed by Parson, C. A. 10, 406. An atom is considered as having an unalterable kernel which possesses an excess of positive charges corresponding in number to the ordinal number of the group in the periodic table to which the element belongs (cf. Thomson, C. A. 8, 824). There is a shell of electrons around the kernel which, in the case of a neutral atom, contains negative electrons equal in number to the excess of positive charges of the kernel, but the number of electrons in the shell may vary during chem. changes between zero and 8. The atom tends to hold an even number of electrons in the shell (especially 8 at the corners of the cube) but the electrons may ordinarily pass from one position to another in this shell. Two atomic shells are mutually interpenetrable. The paper is a discussion of these ideas applied to the structure of atoms and compds.
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130Langmuir, I. Types of valence. Science 1921, 54, 59– 67, DOI: 10.1126/science.54.1386.59130https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaB3MXhvFWqsg%253D%253D&md5=ec20c36dc54a6fdb48f37c579b6c4579Types of valenceLangmuir, IrvingScience (Washington, DC, United States) (1921), 54 (), 59-67CODEN: SCIEAS; ISSN:0036-8075.Three postulates are made. They are consistent with those previously proposed by L. in the Lewis-Langmuir theory of at. structure. This new method of deriving the relation of structure of the atom and types of valence is very much simpler. New ideas of the relationship between the different types of valence are brought out. Compds. are classified according to the types of valence of their atoms into (1) complete compds., (2) incomplete compds., (3) exceptional cases. The theory accounts for the structure of the first two classes of compds. This is an important paper in the development of the at. structure theory.
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131Pyykkö, P. Understanding the eighteen-electron rule. J. Organomet. Chem. 2006, 691, 4336– 4340, DOI: 10.1016/j.jorganchem.2006.01.064There is no corresponding record for this reference.
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132Dognon, J. P.; Clavaguéra, C.; Pyykkö, P. Towards a 32-electron principle: Pu@Pb12 and related systems. Angew. Chem., Int. Ed. 2007, 46, 1427– 1430, DOI: 10.1002/anie.200604198132https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXitleisLk%253D&md5=0d4b8d077fd40404adbaf2832f3b8730Towards a 32-electron principle: Pu@Pb12 and related systemsDognon, Jean-Pierre; Clabaguera, Carine; Pyykko, PekkaAngewandte Chemie, International Edition (2007), 46 (9), 1427-1430CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The predicted endohedral icosahedral clusters Pu@Pb12 and [Am@Pb12]+ have an outermost 32-electron system corresponding to formally occupied 7s, 7p, 6d, and 5f actinide orbitals, each of which interacts with a Pb 6p-based orbital of the [Pb12]2- cage. This study provides the first example of a formal 32-electron principle, and 32 is not a false magic no. Data are presented also on Pb122-, Yb@Pb12, [Th@Pb12]4-, [U@Pb12]2-, [Np@Pb12]-, and [Cm@Pb12]2+.
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133Hirsch, A.; Chen, Z.; Jiao, H. Spherical aromaticity in Ih symmetrical fullerenes: The 2(N+1)2 rule. Angew. Chem., Int. Ed. 2000, 39, 3915– 3917, DOI: 10.1002/1521-3773(20001103)39:21<3915::AID-ANIE3915>3.0.CO;2-O133https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXotF2jsL4%253D&md5=88f0ed0ac5ad731533a40dbe08d91145Spherical aromaticity in Ih symmetrical fullerenes: The 2(N+1)2 ruleHirsch, Andreas; Chen, Zhongfang; Jiao, HaijunAngewandte Chemie, International Edition (2000), 39 (21), 3915-3917CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)The authors demonstrate that the total diatropy of icosahedral fullerenes such as C20, C60, and C80, and their cluster distortion depend on the degree of the electron occupation in the valence shell. The resulting 2(N+1)2 rule for spherical aromaticity represents the spherical analog to the 4N+2 rule for the cyclic annulenes.
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134Chen, Z.; Jiao, H.; Hirsch, A.; Thiel, W. The 2(N+1)2 rule for spherical aromaticity: further validation. J. Mol. Model. 2001, 7, 161– 163, DOI: 10.1007/s008940100021134https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXms1OitLw%253D&md5=542548d93400d69d55e22b2782a8fb5dThe 2(N+1)2 rule for spherical aromaticity: further validationChen, Zhongfang; Jiao, Haijun; Hirsch, Andreas; Thiel, WalterJournal of Molecular Modeling [online computer file] (2001), 7 (5), 161-163CODEN: JMMOFK; ISSN:0948-5023. (Springer-Verlag)Max. spherical aromaticity occurs in icosahedral fullerenes when the valence π-shells are completely filled with 2(N+1)2 electrons. Ab initio calcns. of nucleus-independent chem. shifts show that this rule can also be applied to less sym. small fullerenes and H clusters.
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135Hückel, E. Quantentheoretische beiträge zum benzolproblem. Eur. Phys. J. A 1931, 70, 204– 286, DOI: 10.1007/BF01339530There is no corresponding record for this reference.
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136Chen, Z.; Wannere, C. S.; Corminboeuf, C.; Puchta, R.; Schleyer, P. V. R. Nucleus-independent chemical shifts (NICS) as an aromaticity criterion. Chem. Rev. 2005, 105, 3842– 3888, DOI: 10.1021/cr030088+136https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVGisrbF&md5=85a30c551bbbc0439ceab177216a14e3Nucleus-Independent Chemical Shifts (NICS) as an Aromaticity CriterionChen, Zhongfang; Wannere, Chaitanya S.; Corminboeuf, Clemence; Puchta, Ralph; Schleyer, Paul von RagueChemical Reviews (Washington, DC, United States) (2005), 105 (10), 3842-3888CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A comprehensive review is presented on nucleus-independent chem. shift as a criterion for aromaticity.
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137Hirsch, A.; Chen, Z.; Jiao, H. Spherical aromaticity of inorganic cage molecules. Angew. Chem., Int. Ed. 2001, 40, 2834– 2838, DOI: 10.1002/1521-3773(20010803)40:15<2834::AID-ANIE2834>3.0.CO;2-H137https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXmt1Wlsrs%253D&md5=9ab32d3386a23bd44d10c45fa36e0828Spherical aromaticity of inorganic cage moleculesHirsch, Andreas; Chen, Zhongfang; Jiao, HaijunAngewandte Chemie, International Edition (2001), 40 (15), 2834-2838CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)Recently the authors (ibidem 2000) demonstrated that the icosahedral fullerenes C20, C60, and C80 reach their max. spherical aromaticity if their π shells are completely filled. This treatment of spherical aromaticity is extended to a set of well-known inorg. cage compds., for which it is demonstrated that they are highly arom. because of the closed-shell nature of both their σ and π systems. The optimized bond lengths and nucleus-independent chem. shifts (NICS) were calcd. for the tetrahedral E4 clusters (E = N, P, As, Sb, and Bi), the E3H3 rings, and HE4+ with C3v symmetry. The same is done for the tetrahedral cluster ions E44- (E = Si, Ge, Sn, and Pb) as well as for the E94- (E = Si, Ge, Sn, Pb) and Bi95+ species with D3h and C4v symmetry, and the E92- (E = Ge, Sn, Pb) clusters and Bi97+ with D3h symmetry. In contrast to the fullerenes, the HOMOs within the highly sym. inorg. cage compds. are σ orbitals. The spherical (2Nπ + 1)2 aromaticity of the fullerenes is reached when the π shells are filled. The double spherical aromaticity of the inorg. cage compds. is also a consequence of the complete filling of the corresponding shells, but, here, the whole π and σ systems are involved.
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138Clemenger, K. Ellipsoidal shell structure in free-electron metal clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1985, 32, 1359– 1362, DOI: 10.1103/PhysRevB.32.1359138https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXkslyrtrk%253D&md5=9cf05451bd6b6a0ecafe77d0c67d935fEllipsoidal shell structure in free-electron metal clustersClemenger, KeithPhysical Review B: Condensed Matter and Materials Physics (1985), 32 (2), 1359-62CODEN: PRBMDO; ISSN:0163-1829.The possibility of ellipsoidal distortions in free-electron metal clusters, analogous to the shape variations among at. nuclei, was investigated with the use of a modified Nilsson Hamiltonian. In most cases, the predicted equil. shape is ellipsoidal rather than spherical, so that the spherical shells are divided into ellipsoidal subshells. A strong correlation was obsd. between the energy-level sequence of these subshells and the sequence of peaks in alkali-metal cluster mass spectra, indicating that metal clusters generally assume approx. ellipsoidal shapes.
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139Wade, K. The structural significance of the number of skeletal bonding electron-pairs in carboranes, the higher boranes and borane anions, and various transition-metal carbonyl cluster compounds. J. Chem. Soc. D 1971, 792– 793, DOI: 10.1039/c29710000792139https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE3MXkvFylsrs%253D&md5=977fd8681f8e0d395283e8e53b798064Structural significance of the number of skeletal bonding electron-pairs in carboranes, the higher boranes, and borane anions, and various transition metal carbonyl cluster compoundsWade, K.Journal of the Chemical Society [Section] D: Chemical Communications (1971), (15), 792-3CODEN: CCJDAO; ISSN:0577-6171.The skeletal structures of carboranes, the higher boranes and borane anions, and transition metal carbonyl cluster compds. [e.g., Ru6(CO)182-, Fe5(CO)15C, and Fe3(CO)9S2] are related to the no. of skeletal bonding electron pairs they contain; species with n skeletal atoms adopt closo structures if held together by (n + 1) pairs, nido structures if held together by (n + 2) pairs, and arachno structures if held together by (n + 3) pairs of skeletal bonding electrons.
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140Mingos, D. M. P. Polyhedral Skeletal Electron Pair Approach. Acc. Chem. Res. 1984, 17, 311– 319, DOI: 10.1021/ar00105a003140https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXltlOisb8%253D&md5=0587a193864cbb8a00468579c76ccb56Polyhedral skeletal electron pair approachMingos, D. Michael P.Accounts of Chemical Research (1984), 17 (9), 311-19CODEN: ACHRE4; ISSN:0001-4842.A review with numerous refs. with discussion of polyhedral mol. structures and their electron configurations.
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141Mingos, D. M. P.; Slee, T.; Zhenyang, L. Bonding models for ligated and bare clusters. Chem. Rev. 1990, 90, 383– 402, DOI: 10.1021/cr00100a003141https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXhsVGlurw%253D&md5=4fe459738498ba6eb5dd5b0bffb67645Bonding models for ligated and bare clustersMingos, D. Mike P.; Slee, Tom; Zhenyang, LinChemical Reviews (Washington, DC, United States) (1990), 90 (2), 383-402CODEN: CHREAY; ISSN:0009-2665.A review with 130 refs. of theor. methods applicable to gas-phase bare clusters and condensed-phase ligated clusters. The jellium and LCAO approaches are compared and the application of electron-counting rules to mol.-beam clusters is discussed.
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142Duncan, M. A. Invited review article: laser vaporization cluster sources. Rev. Sci. Instrum. 2012, 83, 041101, DOI: 10.1063/1.3697599142https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XlsVaisL0%253D&md5=2e77e119fbd87aaf5be7b9b757790326Invited Review Article: Laser vaporization cluster sourcesDuncan, Michael A.Review of Scientific Instruments (2012), 83 (4), 041101/1-041101/19CODEN: RSINAK; ISSN:0034-6748. (American Institute of Physics)A review. The laser vaporization cluster source was used for the prodn. of gas phase at. clusters and metal-mol. complexes for 30 years. Numerous expts. in the chem. and physics of clusters have employed this source. Its operation is simple in principle, but there are many subtle design features that influence the no. and size of clusters produced, as well as their compn., charge state, and temp. This article examines all aspects of the design of these cluster sources, discussing the relevant chem., physics, and mech. aspects of exptl. configurations employed by different labs. The principles detailed here provide a framework for the design and implementation of this source for new applications. (c) 2012 American Institute of Physics.
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143Cox, D.; Trevor, D.; Whetten, R.; Rohlfing, E.; Kaldor, A. Aluminum clusters: Magnetic properties. J. Chem. Phys. 1986, 84, 4651– 4656, DOI: 10.1063/1.449991143https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XitlGkur0%253D&md5=806a8f69f95348a65b48ef3d0645fb1cAluminum clusters: magnetic propertiesCox, D. M.; Trevor, D. J.; Whetten, R. L.; Rohlfing, E. A.; Kaldor, A.Journal of Chemical Physics (1986), 84 (8), 4651-6CODEN: JCPSA6; ISSN:0021-9606.The magnetic moments were measured of gas-phase Al clusters ranging in size from 2 to 25 atoms. Al clusters were produced by pulsed-laser vaporization of an Al rod inside the throat of a high-pressure pulsed nozzle. Al clusters <9 atoms in size have magnetic moments generally consistent with those predicted from spin and orbital moments of the ground electronic states. As expected, a general trend toward reduced magnetic moment per atom with increasing cluster size is obsd.
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144Kumar, V. Structure and electronic properties of Al14 and Al13Na clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1998, 57, 8827– 8829, DOI: 10.1103/PhysRevB.57.8827144https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXisVGju7k%253D&md5=e353a921dc2b33995310e98e7886f4cdStructure and electronic properties of Al14 and Al13Na clustersKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (1998), 57 (15), 8827-8829CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio mol. dynamics simulations on the Al14 cluster show that in the capped icosahedron structure of this cluster, the 3s electrons of the capping Al atom behave more like core electrons, giving rise to an electronic shell closure effect known for simple metal clusters with 40 valence electrons and which we also find for Al13Na. This makes the two clusters magic. Al14 has a higher binding energy than Al13. However, the HOMO-LUMO gap in Al14 is lower than in Al13 whereas in the case of Al13Na it increases. These results are in complete agreement with the observation of a lower ionization potential for Al14 and a higher ionization potential for Al13Na.
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145Jarrold, M. F.; Bower, J. E. The reactions of mass selected aluminum cluster ions, Al+n (n = 4–25), with oxygen. J. Chem. Phys. 1986, 85, 5373– 5375, DOI: 10.1063/1.451157145https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXhtF2hsg%253D%253D&md5=0f8b066d88b01f14d6db36bba8efc831The reactions of mass selected aluminum cluster ions, Aln+ (n = 4-25), with oxygenJarrold, Martin F.; Bower, J. EricJournal of Chemical Physics (1986), 85 (9), 5373-5CODEN: JCPSA6; ISSN:0021-9606.The reactions were studied of mass selected Aln+ (n = 4-25) with O2. The products and unreacted ions were analyzed with a quadrupole mass spectrometer. E.g. Al16+ gave Al12+ (90%) and Al11+ (10%) as detectable ions. No O-contg. product ions were obsd. for any of the clusters studied; the significance of this result is discussed.
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146Thomas, O. C.; Zheng, W.; Bowen, K. H., Jr Magic numbers in copper-doped aluminum cluster anions. J. Chem. Phys. 2001, 114, 5514– 5519, DOI: 10.1063/1.1349547146https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXitFKltrg%253D&md5=1615c636392710c8ffb98627a4da35dbMagic numbers in copper-doped aluminum cluster anionsThomas, Owen C.; Zheng, Weijun; Bowen, Kit H., Jr.Journal of Chemical Physics (2001), 114 (13), 5514-5519CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Copper-doped aluminum cluster anions, CuAln- were generated in a laser vaporization source and examd. via mass spectrometry (n=2-30) and anion photoelectron spectroscopy (n=2-15). The mass spectrum of the CuAln- series is dominated by CuAl13- with other magic nos. also appearing at n=6, 19, and 23. The electron affinity vs. cluster size trend shows a peak at n=6 and a dip at n=13. These results are discussed in terms of the reordering of shell model energy levels and the enhanced stability of neutral CuAl13. Reordering, which is a consequence of the copper atom residing in the central region of these clusters, provides an anion-oriented electronic rationale for the obsd. magic nos.
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147Taylor, K.; Pettiette, C.; Craycraft, M.; Chesnovsky, O.; Smalley, R. Ups of negative aluminum clusters. Chem. Phys. Lett. 1988, 152, 347– 352, DOI: 10.1016/0009-2614(88)80104-0147https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXkslygsQ%253D%253D&md5=49af372eb02d11473b4481ca8a687f3bUPS of negative aluminum clustersTaylor, K. J.; Pettiette, C. L.; Craycraft, M. J.; Chesnovsky, O.; Smalley, R. E.Chemical Physics Letters (1988), 152 (4-5), 347-52CODEN: CHPLBC; ISSN:0009-2614.UPS of neg. Al clusters in the size range of 3-32 atoms is presented. The clusters were prepd. in a supersonic beam by laser vaporization, and an ArF excimer laser (6.42 eV) was used for photodetachment. The electron affinities of the neutral clusters are peaked at cluster sizes of 6, 13, 19, and 23, which is consistent with a shell model of electronic structure. A size-dependent increase in the photoelectron yield at 5 eV binding energy in the UPS data was interpreted as the merging of the 3s and 3p valence bands.
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148Ma, L.; v. Issendorff, B.; Aguado, A. Photoelectron spectroscopy of cold aluminum cluster anions: Comparison with density functional theory results. J. Chem. Phys. 2010, 132, 104303, DOI: 10.1063/1.3352445148https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjt1aksbo%253D&md5=a65ea3e26a779a8da80e0134565e0b5cPhotoelectron spectroscopy of cold aluminum cluster anions: comparison with density functional theory resultsMa, Lei; von Issendorff, Bernd; Aguado, AndresJournal of Chemical Physics (2010), 132 (10), 104303/1-104303/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Photoelectron spectra of cold Al cluster anions Aln- were measured in the size range n = 13-75 and are compared to the results of d. functional theory calcns. Good agreement between the measured spectra and the calcd. d. of states is obtained for most sizes, which gives strong evidence that the correct structures were found. In particular the results confirm the occurrence of rather different structural motifs in this size range, from fcc.-like stacks over fragments of decahedrons to disordered structures. An anal. of the d. of states of representatives of the different structural motifs shows that the electronic structure is strongly influenced by the cluster geometry, and that a clear jelliumlike electron shell structure is present only in some exceptional cases. (c) 2010 American Institute of Physics.
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149Bergeron, D. E.; Castleman, A. W.; Morisato, T.; Khanna, S. N. Formation of Al13I-: Evidence for the superhalogen character of Al13. Science 2004, 304, 84– 87, DOI: 10.1126/science.1093902149https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXis1antro%253D&md5=1b0840ceb9dd79895511c15613508d98Formation of Al13I-: Evidence for the Superhalogen Character of Al13Bergeron, Denis E.; Castleman, A. Welford, Jr.; Morisato, Tsuguo; Khanna, Shiv N.Science (Washington, DC, United States) (2004), 304 (5667), 84-87CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Al13- is a cluster known for the pronounced stability that arises from coincident closures of its geometric and electronic shells. We present exptl. evidence for a very stable cluster corresponding to Al13I-. Ab initio calcns. show that the cluster features a structurally unperturbed Al13- core and a region of high charge d. on the aluminum vertex opposite from the iodine atom. This ionically bound magic cluster can be understood by considering that Al13 has an electronic structure reminiscent of a halogen atom. Comparisons to polyhalides provide a sound explanation for our chem. observations.
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150Kambe, T.; Haruta, N.; Imaoka, T.; Yamamoto, K. Solution-phase synthesis of Al13– using a dendrimer template. Nat. Commun. 2017, 8, 2046, DOI: 10.1038/s41467-017-02250-4150https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MzgsVWgtw%253D%253D&md5=a096ecdf7e092b8de4684962e2ab8593Solution-phase synthesis of Al13(-) using a dendrimer templateKambe Tetsuya; Imaoka Takane; Yamamoto Kimihisa; Kambe Tetsuya; Haruta Naoki; Imaoka Takane; Yamamoto Kimihisa; Imaoka TakaneNature communications (2017), 8 (1), 2046 ISSN:.Superatoms, clusters that mimic the properties of elements different to those of which they are composed, have the potential to serve as building blocks for unprecedented materials with tunable properties. The development of a method for the solution-phase synthesis of superatoms would be an indispensable achievement for the future progress of this research field. Here we report the fabrication of aluminum clusters in solution using a dendrimer template, producing Al13(-), which is the most well-known superatom. The Al13(-) cluster is identified using mass spectrometry and scanning transmission electron microscopy, and X-ray photoelectron spectroscopy is used to measure the binding energies. The superatomic stability of Al13(-) is demonstrated by evaluating its tendency toward oxidation. In addition, the synthesis of Al13(-) in solution enables electrochemical measurements, the results of which suggest oxidation of Al13(-). This solution-phase synthesis of Al13(-) superatoms has a significant role for the experimental development of cluster science.
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151Ko, Y. J.; Shakya, A.; Wang, H.; Grubisic, A.; Zheng, W.; Götz, M.; Ganteför, G.; Bowen, K. H.; Jena, P.; Kiran, B. Electronic structure and properties of isoelectronic magic clusters: Al13X (X = H, Au, Li, Na, K, Rb, Cs). J. Chem. Phys. 2010, 133, 124308, DOI: 10.1063/1.3490401151https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht1Slur3F&md5=3f5da6fce491c6afe3d7d88caf1021e4Electronic structure and properties of isoelectronic magic clusters: Al13X (X=H,Au,Li,Na,K,Rb,Cs)Ko, Yeon Jae; Shakya, Anisha; Wang, Haopeng; Grubisic, Andrej; Zheng, Weijun; Goetz, Matthias; Gantefoer, Gerd; Bowen, Kit H.; Jena, Puru; Kiran, BoggavarapuJournal of Chemical Physics (2010), 133 (12), 124308/1-124308/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The equil. structure, stability, and electronic properties of the Al13X (X = H,Au,Li,Na,K,Rb,Cs) clusters have been studied using a combination of photoelectron spectroscopy expt. and d. functional theory. All these clusters constitute 40 electron systems with 39 electrons contributed by the 13 Al atoms and 1 electron contributed by each of the X (X = H,Au,Li,Na,K,Rb,Cs) atom. A systematic study allows us to investigate whether all electrons contributed by the X atoms are alike and whether the structure, stability, and properties of all the magic clusters are similar. Furthermore, quant. agreement between the calcd. and the measured electron affinities and vertical detachment energies enable us to identify the ground state geometries of these clusters both in neutral and anionic configurations. (c) 2010 American Institute of Physics.
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152Khanna, S.; Jena, P. Assembling crystals from clusters. Phys. Rev. Lett. 1992, 69, 1664– 1667, DOI: 10.1103/PhysRevLett.69.1664152https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XlvFyqsbc%253D&md5=0aed03f093b373861ea47cf02638bb2eAssembling crystals from clustersKhanna, S. N.; Jena, P.Physical Review Letters (1992), 69 (11), 1664-7CODEN: PRLTAO; ISSN:0031-9007.The stability of a cluster can be substantially enhanced by changing its size and/or compn. so as to take advantage of the electronic shell filling as well as close at. packing. The interaction between two such clusters is found to be weak and can form the basis for synthesizing a new class of cluster-assembled crystals with uncommon properties.
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153Nakajima, A.; Kishi, T.; Sugioka, T.; Kaya, K. Electronic and geometric structures of aluminum-boron negative cluster ions (AlnB–m). Chem. Phys. Lett. 1991, 187, 239– 244, DOI: 10.1016/0009-2614(91)90419-AThere is no corresponding record for this reference.
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154Smith, J. C.; Reber, A. C.; Khanna, S. N.; Castleman, A., Jr Boron substitution in aluminum cluster anions: Magic clusters and reactivity with oxygen. J. Phys. Chem. A 2014, 118, 8485– 8492, DOI: 10.1021/jp501934t154https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXlvFCrtrw%253D&md5=7755f0dc2abda2852399a9f0125f8b42Boron Substitution in Aluminum Cluster Anions: Magic Clusters and Reactivity with OxygenSmith, Jordan C.; Reber, Arthur C.; Khanna, Shiv N.; Castleman, A. W.Journal of Physical Chemistry A (2014), 118 (37), 8485-8492CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We have studied the size-selective reactivity of AlnBm- clusters m = 1,2 with O2 to investigate the effect of congener substitution in energetic aluminum clusters. Mixed-metal clusters offer an addnl. strategy for tuning the electronic and geometric structure of clusters and by substituting an atom with a congener; we may investigate the effect of structural changes in clusters with similar electronic structures. Using a fast-flow tube mass spectrometer, we formed aluminum boride cluster anions and exposed them to mol. oxygen. We found multiple stable species with Al12B- and Al11B2- being highly resistant to reactivity with oxygen. These clusters behave in a similar manner as Al13-, which has previously been found to be stable in oxygen because of its icosahedral geometry and its filled electronic shell. Al13- and Al12B- have icosahedral structures, while Al11B2- forms a distorted icosahedron. All three of these clusters have filled electronic shells, and Al12B- has a larger HOMO-LUMO gap due to its compact geometry. Other cluster sizes are investigated, and the structures of the AlnB- series (n = 5-16) are found to have endohedrally doped B atoms, as do many of the AlnB2- (n = 4 - 15) clusters. The primary etching products are found to be a loss of two Al2O mols., with boron likely to remain in the cluster.
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155Pal, R.; Cui, L.-F.; Bulusu, S.; Zhai, H.-J.; Wang, L.-S.; Zeng, X. C. Probing the electronic and structural properties of doped aluminum clusters: MAl12– (M = Li, Cu, and Au). J. Chem. Phys. 2008, 128, 024305, DOI: 10.1063/1.2805386155https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosVKruw%253D%253D&md5=3da0ed0aa40cfe8976c4370939804582Probing the electronic and structural properties of doped aluminum clusters: MAl12- (M = Li, Cu, and Au)Pal, R.; Cui, Li-Feng; Bulusu, S.; Zhai, Hua-Jin; Wang, Lai-Sheng; Zeng, X. C.Journal of Chemical Physics (2008), 128 (2), 024305/1-024305/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Photoelectron spectroscopy (PES) is combined with theor. calcns. to study the electronic and at. structures of 3 doped Al clusters, MAl12- (M = Li, Cu, and Au). Well-resolved PES spectra were obtained at 2 detachment photon energies, 266 nm (4.661 eV) and 193 nm (6.424 eV). Basin-hopping global optimization method in combination with d.-functional theory calcns. was used for the structural searches. Good agreement between the measured PES spectra and theor. simulations helps to identify the global min. structures. LiAl12- (C5v) can be viewed as replacing a surface Al atom by Li on an icosahedral Al13-, whereas Cu prefers the central site to form the encapsulated D3d-Cu@Al12-. For AuAl12- (C1), Au also prefers the central site, but severely distorts the Al12 cage due to its large size. (c) 2008 American Institute of Physics.
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156Kawamata, H.; Negishi, Y.; Nakajima, A.; Kaya, K. Electronic properties of substituted aluminum clusters by boron and carbon atoms (AlnBm–/AlnCm–); new insights into s–p hybridization and perturbed shell structures. Chem. Phys. Lett. 2001, 337, 255– 262, DOI: 10.1016/S0009-2614(01)00198-1156https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXisFGmsLk%253D&md5=bd897c41f45aab0e29d67efaad462ec6Electronic properties of substituted aluminum clusters by boron and carbon atoms (AlnBm-/AlnCm-); new insights into s-p hybridization and perturbed shell structuresKawamata, H.; Negishi, Y.; Nakajima, A.; Kaya, K.Chemical Physics Letters (2001), 337 (4,5,6), 255-262CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Substituted Al clusters with B atom, which is trivalent but smaller than Al atom, or with covalent C atom were investigated using photoelectron spectroscopy (PES). In Aln-mBm- (n ≥ 5 for m = 1, n ≥ 10 for m = 2), three valence electrons of each B atom as well as Al atom contribute to electron shell structures, while the C atom strongly binds two free electrons from Aln- in AlnC- (n = 5-30). The substitution with B atom allowed us to det. that s-p mixing starts at n = 6 in pure Al clusters. Perturbed electron shells and the geometry of Al12B1-, Al11B2-, and Al12C- are discussed.
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157Lang, S. M.; Claes, P.; Neukermans, S.; Janssens, E. Cage structure formation of singly doped aluminum cluster cations AlnTM+(TM= Ti, V, Cr). J. Am. Soc. Mass Spectrom. 2011, 22, 1508, DOI: 10.1007/s13361-011-0181-1157https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFaqs7fF&md5=7d5807e1cab8589a35a863443d295e20Cage structure formation of singly doped aluminum cluster cations AlnTM+ (TM = Ti, V, Cr)Lang, Sandra M.; Claes, Pieterjan; Neukermans, Sven; Janssens, EwaldJournal of the American Society for Mass Spectrometry (2011), 22 (9), 1508-1514CODEN: JAMSEF; ISSN:1044-0305. (Springer)Structural information on free transition metal doped aluminum clusters, AlnTM+ (TM = Ti, V, Cr), was obtained by studying their ability for argon physisorption. Systematic size (n = 5 - 35) and temp. (T = 145 - 300 K) dependent investigations reveal that bare Aln+ clusters are inert toward argon, while AlnTM+ clusters attach one argon atom up to a crit. cluster size. This size is interpreted as the geometrical transition from surface-located dopant atoms to endohedrally doped aluminum clusters with the transition metal atom residing in an aluminum cage. The crit. size, ncrit, is found to be surprisingly large, namely ncrit = 16 and ncrit = 19 - 21 for TM = V, Cr, and TM = Ti, resp. Exptl. cluster-argon bond dissocn. energies were derived as function of cluster size from equil. mass spectra and are in the 0.1-0.3 eV range.
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158Akutsu, M.; Koyasu, K.; Atobe, J.; Miyajima, K.; Mitsui, M.; Tsunoyama, H.; Nakajima, A. Geometric and electronic properties of Si-atom doped Al clusters: robustness of binary superatoms against charging. Phys. Chem. Chem. Phys. 2017, 19, 20401– 20411, DOI: 10.1039/C7CP03409A158https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFCit7zP&md5=cea4af432850699dd1d8e10b1668e23eGeometric and electronic properties of Si-atom doped Al clusters: robustness of binary superatoms against chargingAkutsu, Minoru; Koyasu, Kiichirou; Atobe, Junko; Miyajima, Ken; Mitsui, Masaaki; Tsunoyama, Hironori; Nakajima, AtsushiPhysical Chemistry Chemical Physics (2017), 19 (31), 20401-20411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The geometric and electronic properties of silicon-atom-doped aluminum clusters, AlnSim (n = 7-30, m = 0-2), were investigated exptl. The size dependences of the ionization energy and electron affinity of AlnSim show that the stability of AlnSim is governed by the total no. of valence electrons in the clusters, where Al and Si atoms behave as trivalent and tetravalent atoms, resp. Together with theor. calcns., it has been revealed that neutral Al10Si and Al12Si have a cage-like geometry with central Si atom encapsulation and closed electronic structures of superat. orbitals (SAOs), and also that they both exhibit geometric robustness against reductive and oxidative changes as cage-like binary superatoms of Si@Al10 and Si@Al12. As well as the single-atom-doped binary superatoms, the effect of symmetry lowering was examd. by doping a second Si atom toward the electron SAO closing of 2P SAO, forming Al11Si2. The corresponding anion and cation clusters keep their geometry of the neutral intact, and the ionization energy is low compared to others, showing that Al11Si2 is characterized to be, Si@Al11Si as an alk.-like binary superatom. For Al21Si2, a face-sharing bi-icosahedral structure was identified to be the most stable as dimeric superatom clusters.
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159Akutsu, M.; Koyasu, K.; Atobe, J.; Hosoya, N.; Miyajima, K.; Mitsui, M.; Nakajima, A. Experimental and theoretical characterization of aluminum-based binary superatoms of Al12X and their cluster salts. J. Phys. Chem. A 2006, 110, 12073– 12076, DOI: 10.1021/jp065161p159https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVyrsb7O&md5=76e9faaeef775f9b41ddf1c0b5008304Experimental and Theoretical Characterization of Aluminum-Based Binary Superatoms of Al12X and Their Cluster SaltsAkutsu, Minoru; Koyasu, Kiichirou; Atobe, Junko; Hosoya, Natsuki; Miyajima, Ken; Mitsui, Masaaki; Nakajima, AtsushiJournal of Physical Chemistry A (2006), 110 (44), 12073-12076CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The geometric and electronic structures of aluminum binary clusters, AlnX (X = Si and P), have been investigated, using mass spectrometry, anion photoelectron spectroscopy, photoionization spectroscopy, and theor. calcns. Both exptl. and theor. results show that Al12Si has a high ionization energy and low electron affinity and Al12P has a low ionization energy, both with the icosahedral structure having a central Si or P atom, revealing that Al12Si and Al12P exhibit rare-gas-like and alkali superatoms, resp. Expts. confirmed the possibility that the change in the total no. of valence electrons on substitution could produce ionically bound binary superatom complexes, the binary cluster salts Al12P+F- and Al12B-Cs+.
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160Li, X.; Wang, L.-S. Experimental search and characterization of icosahedral clusters: Al12X– (X = C, Ge, Sn, Pb). Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 65, 153404, DOI: 10.1103/PhysRevB.65.153404160https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjtV2nsbg%253D&md5=3d4277a77db43d5febd6024a51e99901Experimental search and characterization of icosahedral clusters: Al12X- (X=C, Ge, Sn, Pb)Li, Xi; Wang, Lai-ShengPhysical Review B: Condensed Matter and Materials Physics (2002), 65 (15), 153404/1-153404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Photoelectron spectra of Al12X- (X=C, Ge, Sn, Pb) probe the electronic structure of Al12X. These clusters, all possessing 40 valence electrons, were expected to be magic nos. with Ih-X@Al12 structures, closed electron shells, and large energy gaps. For X = Ge, Sn, and Pb that was indeed the case, although non-Ih isomers were also obsd. The energy gaps of the 3 Ih-X@Al12 species range from 1.1 to 1.3 eV. The spectra of Al12C- were distinctly different from the other species, confirming that it does not possess an icosahedral structure.
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161Seitsonen, A. P.; Laasonen, K.; Nieminen, R. M.; Klein, M. L. Structure of CAl12. J. Chem. Phys. 1995, 103, 8075– 8080, DOI: 10.1063/1.470172161https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXptFWqurc%253D&md5=9ffcee77278f1ac7f21d7809de337c19Structure of CAl12Seitsonen, Ari P.; Laasonen, Kari; Nieminen, R. M.; Klein, Michael L.Journal of Chemical Physics (1995), 103 (18), 8075-80CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures of an isolated CAl12 cluster and a solid composed of CAl12 clusters have been studied using the Car-Parrinello method, based on the d. functional theory and the local d. approxn. We have compared the results of using the ultrasoft Vanderbilt pseudopotential with those of both a traditional pseudopotential and a LCAO method. We have confirmed the high stability of the cluster in its icosahedral structure. However, we show that the cluster-assembled solid is unstable against melting of the clusters, as previously found for SiAl12.
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162Li, S.; Gong, X. Neutral and negatively charged Al12X (X = Si, Ge, Sn, Pb) clusters studied from first principles. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 045432, DOI: 10.1103/PhysRevB.74.045432162https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XotFWntb4%253D&md5=b7729adf5cec953fa7700b19659b8345Neutral and negatively charged Al12X (X = Si, Ge, Sn, Pb) clusters studied from first principlesLi, S. F.; Gong, X. G.Physical Review B: Condensed Matter and Materials Physics (2006), 74 (4), 045432/1-045432/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The ground states properties of the title clusters were calcd. by DFT-GGA method. All clusters prefer icosahedral structure, in agreement with previous calcns. However, each of Al12X (X = Ge, Sn, Pb) neutral and ionic clusters shows C5v symmetry with atom X located on the cluster surface, contrary to the conclusion from the previous exptl. work [Phys. Rev. B 65, 153404 (2002)].
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163Kumar, V.; Sundararajan, V. Ab initio molecular-dynamics studies of doped magic clusters and their interaction with atoms. Phys. Rev. B: Condens. Matter Mater. Phys. 1998, 57, 4939– 4942, DOI: 10.1103/PhysRevB.57.4939163https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXhtFyju7s%253D&md5=7a2328cdd8241fc489196699cc2d9d1eAb initio molecular-dynamics studies of doped magic clusters and their interaction with atomsKumar, Vijay; Sundararajan, V.Physical Review B: Condensed Matter and Materials Physics (1998), 57 (8), 4939-4942CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We present results of the at. and electronic structures of icosahedral Al12X (X = Si, Ge, and Sn) clusters using the ab initio mol.-dynamics method within the local-d.-functional theory. Substitutional doping of a Al13 cluster by a tetravalent atom leads to a substantial gain in energy in all the cases studied. Tin is found to have a lower energy at a vertex site in contrast to the central site for Si and Ge, leading to surface segregation of Sn in these clusters. Also in the case of a Al13Si cluster, Si occupies the central site of a capped icosahedral structure. These results when interpreted in terms of the interaction of closed shell clusters with atoms leads to a relatively strong interaction of Al12Si with Al as compared to the weak interaction of rare gas atoms with other elements.
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164Kumar, V.; Bhattacharjee, S.; Kawazoe, Y. Silicon-doped icosahedral, cuboctahedral, and decahedral clusters of aluminum. Phys. Rev. B: Condens. Matter Mater. Phys. 2000, 61, 8541– 8547, DOI: 10.1103/PhysRevB.61.8541164https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhvVSnsrY%253D&md5=670c529946f603bb0207ac9ce5e4412aSilicon-doped icosahedral, cuboctahedral, and decahedral clusters of aluminumKumar, Vijay; Bhattacharjee, Satadeep; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2000), 61 (12), 8541-8547CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Most stable structures and phys. properties were studied for silicon-doped Al13, Al19, and Al23 clusters using the ab initio mol.-dynamics method within the framework of a plane-wave pseudopotential approach and the local d. as well as the generalized gradient approxns. The lowest energy structures of the undoped clusters were found to be Jahn-Teller distorted icosahedron, double icosahedron, and decahedron, resp. Substitutional doping with a Si impurity makes these clusters electronically closed shell and leads to a large gain in the binding energy, which decreases with an increase in the cluster size in a nonmonotonic way. The heat of soln. of a Si atom in clusters was found to be exothermic as compared to endothermic behavior in bulk aluminum. A Si impurity was found to stabilize the Al18Si cluster in cuboctahedral structure. However, a capped icosahedron as well as a double icosahedron were found to be nearly degenerate with about 1.77 eV higher binding energy. For Al22Si, the decahedral isomer has the lowest energy with a HOMO-LUMO gap of 0.82 eV. It is also found to be very stable when heated at 700 K. Similar results are likely to hold in the case of doping with germanium. We discuss the significance of these results for the understanding of the stability of silicon-doped quasicrystals.
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165Kumar, V.; Kawazoe, Y. Hund’s rule in metal clusters: Prediction of high magnetic moment state of Al12Cu from first-principles calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2001, 64, 115405, DOI: 10.1103/PhysRevB.64.115405165https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXmsFCjsbo%253D&md5=8b37b03ef7df2757af3e991b22b29349Hund's rule in metal clusters: Prediction of high magnetic moment state of Al12Cu from first-principles calculationsKumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2001), 64 (11), 115405/1-115405/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Using ab initio pseudopotential plane wave method and generalized gradient approxn. for the exchange and correlation energy, we report the finding of high spin ground state of Al12Cu cluster in accordance with the Hund's rule of max. spin at half-filling. It has perfect icosahedral symmetry and a magnetic moment of 3μB, forming an open shell superatom. Further studies of its interaction with an Al atom have led to an electronically closed shell magic cluster with 1.68 eV highest occupied-LUMO (HOMO-LUMO) gap such that the added Al atom is incorporated within the cage around the Cu atom.
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166Chen, G.; Kawazoe, Y. Structural and electronic properties of Al12X+ (X = C, Si, Ge, Sn, and Pb) clusters. J. Chem. Phys. 2007, 126, 014703, DOI: 10.1063/1.2429063166https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXosVCksg%253D%253D&md5=5693ce2c17aa4b279ae6f26503e32851Structural and electronic properties of Al12X+ (X = C, Si, Ge, Sn, and Pb) clustersChen, G.; Kawazoe, Y.Journal of Chemical Physics (2007), 126 (1), 014703/1-014703/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Using the DFT-GGA method (VASP code), the authors have studied the structural and electronic properties of Al12X+ (X = C, Si, Ge, Sn, and Pb) clusters. The ground state of Al12C+ is a low symmetry Cs structure instead of an icosahedron. However, for the Si, Ge, Sn, and Pb cases the icosahedral structure is favored. The ground states of Al12Si+ and Al12Ge+ have icosahedral structures, while the C5ν structures optimized from an icosahedron with a vertex capped by a tetravalent atom have the highest binding energy for Al12Sn+ and Al12Pb+ clusters. The Ih structure and the C5ν structure are almost degenerate for Al12Ge+ with binding energy difference of only 0.03 eV. The electronic properties are altered much by removing an electron from the neutral cluster. The binding strength of a valence electron is enhanced, while the binding energy of the cluster is reduced substantially. Due to the open electronic shell, the HOMO-LUMO gaps are ∼0.3 eV for these clusters.
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167Khanna, S.; Jena, P. Atomic clusters: Building blocks for a class of solids. Phys. Rev. B: Condens. Matter Mater. Phys. 1995, 51, 13705– 13716, DOI: 10.1103/PhysRevB.51.13705167https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXlvVGqtrg%253D&md5=40eea46e945f6802f25c4a3392bd447eAtomic clusters: building blocks for a class of solidsKhanna, S. N.; Jena, P.Physical Review B: Condensed Matter (1995), 51 (19), 13705-16CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)At. clusters with suitable size and compn. can be designed to mimic the chem. of atoms in the Periodic Table. These clusters which can be viewed as "super atoms" could then form the building blocks for a class of solids with unique structural, electronic, optical, magnetic, and thermodn. properties. Using d.-functional calcns., we outline the design principles for these clusters and describe the role of geometry and electronic shell structure on cluster-cluster interaction.
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168Kumar, V. Al10Li8: A magic compound cluster. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 60, 2916– 2920, DOI: 10.1103/PhysRevB.60.2916168https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksFyhsb4%253D&md5=cd5ba35c9864f83673f19452e3cb49e0Al10Li8: A magic compound clusterKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (1999), 60 (4), 2916-2920CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We report the finding of a layered Al10Li8 compd. cluster using the ab initio mol.-dynamics method. It has closed geometric as well as electronic shells and 1.62 eV highest occupied-LUMO (HOMO-LUMO) gap. With 38 valence electrons, it forms a class of magic clusters different from the known magic behavior of s-p-bonded metal clusters with 40 electrons. The bonding in this cluster is covalent between the aluminum atoms and ionic between the Al and Li shells. A similar result has been obtained for Al10Na8. However, the binding energy and HOMO-LUMO gap are smaller. A few other possibilities of larger layered clusters in this system are also discussed.
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169Thomas, O.; Zheng, W.-J.; Lippa, T.; Xu, S.-J.; Lyapustina, S.; Bowen, K., Jr In search of theoretically predicted magic clusters: Lithium-doped aluminum cluster anions. J. Chem. Phys. 2001, 114, 9895– 9900, DOI: 10.1063/1.1365110169https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjvFWhtLg%253D&md5=152ea05cbc590fb8ba16367c5da2136fIn search of theoretically predicted magic clusters: Lithium-doped aluminum cluster anionsThomas, O. C.; Zheng, W.-J.; Lippa, T. P.; Xu, S.-J.; Lyapustina, S. A.; Bowen, K. H., Jr.Journal of Chemical Physics (2001), 114 (22), 9895-9900CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Li-doped Al cluster anions, LiAln- were generated in a laser vaporization source and examd. via mass spectrometry and anion photoelectron spectroscopy (n = 3-15). The mass spectrum of the LiAln- series exhibits a local min. in intensity at n = 13. The electron affinity vs. cluster size trend also shows a dip at n = 13. Agreement is quite good between measured electron affinity values and those calcd. by Rao, Khanna, and Jena, suggesting that their predictions about the structure and bonding of LiAl13 and other clusters in this series are also largely valid.
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170Rao, B.; Jena, P. Energetics and electronic structure of carbon doped aluminum clusters. J. Chem. Phys. 2001, 115, 778– 783, DOI: 10.1063/1.1379973170https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXkslygtL4%253D&md5=493bff60e42563c47fd0a603274f0a92Energetics and electronic structure of carbon doped aluminum clustersRao, B. K.; Jena, P.Journal of Chemical Physics (2001), 115 (2), 778-783CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The energetics and the electronic structure of AlnC clusters (n = 3, 4, 5; 11, 12, 13) have been studied by a global optimization of their geometry without any symmetry constraint. The total energies of these clusters both in neutral and charged states are calcd. using an all-electron basis and the generalized gradient approxn. to the d. functional theory. While Al4C and Al12C clusters share some characteristic features of closed shell structures, namely enhanced stability and low electron affinity compared to their neighboring sizes, their ionization potentials exhibit different behavior. These decrease steadily from Al3C to Al5C while that of Al12C is higher than its neighbors. Carbon is found to form planar structures in small AlnC clusters (n = 3, 4, 5) irresp. of their charge state, although neutral Al4C possesses a nearly degenerate tetrahedral isomer lying slightly higher in energy from the planar configuration. The results agree well with exptl. and previous theor. data. In larger AlnC (n = 11, 12, 13) clusters, carbon occupies an interior site. In Al12C, carbon occupies the center of an icosahedron while it is off-centered in Al11C and Al13C. As an electron is attached, the near degeneracies of the neutral Al4C is lifted, whereas nondegenerate isomers of neutral Al12C yield nearly degenerate anions. Both these features produce complicated photoelectron spectra making identification of their adiabatic electron affinity a difficult problem. With the exception of neutral Al12C, the bonding of carbon to aluminum atoms is governed primarily by covalent interaction. The above calcns. were also performed with a simplified basis by freezing the at. cores of aluminum. In most cases, this simple basis yields results in good agreement with all electron calcns.
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171Khanna, S.; Ashman, C.; Rao, B.; Jena, P. Geometry, electronic structure, and energetics of copper-doped aluminum clusters. J. Chem. Phys. 2001, 114, 9792– 9796, DOI: 10.1063/1.1367381171https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjvFWht70%253D&md5=ffbab28f4a4eabef26f9df662f0d2732Geometry, electronic structure, and energetics of copper-doped aluminum clustersKhanna, S. N.; Ashman, C.; Rao, B. K.; Jena, P.Journal of Chemical Physics (2001), 114 (22), 9792-9796CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Using d. functional theory and generalized gradient approxn. for exchange-correlation potential, we have calcd. the equil. geometries and energetics of neutral and neg. charged AlnCu (n=11,12,13,14) clusters. Unlike the alkali atom-doped aluminum clusters in the same size range, the copper atom resides inside the aluminum cluster cage. Furthermore, the 3d and 4s energy levels of Cu hybridize with the valence electrons of Al causing a redistribution of the MO energy levels of the Aln clusters. However, this redistribution does not affect the magic nos. of AlnCu clusters that could be derived by assuming that Cu donates one electron to the valence levels of Aln clusters. This behavior, brought about by the smaller size and large ionization potential of the copper atom, contributes to the anomalous properties of AlnCu- anions: Unlike AlnX- (X=alkali atom), the mass ion intensities of AlnCu- are similar to those of Aln-. The calcd. adiabatic electron affinities are also in very good agreement with expt.
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172Rao, B.; Khanna, S.; Jena, P. Isomers of Al13 clusters and their interaction with alkali atoms. Phys. Rev. B: Condens. Matter Mater. Phys. 2000, 62, 4666– 4671, DOI: 10.1103/PhysRevB.62.4666172https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXls1Wrt7Y%253D&md5=6c31b6e14421182212a5784ef9ce8a88Isomers of Al13 clusters and their interaction with alkali atomsRao, B. K.; Khanna, S. N.; Jena, P.Physical Review B: Condensed Matter and Materials Physics (2000), 62 (7), 4666-4671CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Global optimization of the geometry of Al13 cluster using the d.-functional theory and generalized gradient approxn. yields two nearly degenerate isomers having Jahn-Teller distorted icosahedral and decahedral structures. As these two isomers of Al13 interact with alkali-atoms X (X=Li, Na, K, Rb, and Cs), the Jahn-Teller distortions in the bare cluster isomers disappear in all cases except in Cs. The binding energy of alkali atoms, X to Al13 systematically decreases from Li to Cs for both the isomers. This is shown to result from a competition between the size and the ionization potential of the alkali atoms. In addn., the difference in the total energies between icosahedral and decahedral structures contg. the alkali atoms becomes smaller than that between the bare Al13 isomers. The vertical ionization potentials of Al3X is larger than that of Al13 in the decahedral structure while the opposite is the case with the icosahedral isomer. The above results based on a frozen core approxn. were repeated using an all-electron basis. While there are quant. differences between these results, these are negligible at the present level of theory.
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173Majumder, C.; Das, G.; Kulshrestha, S.; Shah, V.; Kanhere, D. Ground state geometries and energetics of ALnLi (n = 1, 13) clusters using ab initio density-based molecular dynamics. Chem. Phys. Lett. 1996, 261, 515– 520, DOI: 10.1016/0009-2614(96)01028-7173https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XmslCltLk%253D&md5=b5171b47d12f5d93007365ee8c627a06Ground state geometries and energetics of AlnLi (n = 1, 13) clusters using ab initio density-based molecular dynamicsMajumder, C.; Das, G. P.; Kulshrestha, S. K.; Shah, Vaishali; Kanhere, D. G.Chemical Physics Letters (1996), 261 (4,5), 515-520CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)Based on orbital-free, ab-initio, mol.-dynamics calcns., the geometries and energetics of lithium-doped aluminum clusters (ALnLi, n = 1, 13) have been investigated. It is seen that, a single impurity of Li affects the geometries of small (n < 6) clusters, and this effect is less pronounced for larger clusters. The results suggest extra stability for the Al3Li, Al6Li and Al13Li clusters, which are in contrast with our earlier results on LinAl. The results indicate that the Li atom segregates to the surface of the aluminum cluster and prefers to form a tetrahedron, wherever possible, with one of the triangular faces of Al atoms. In particular, for Al13Li, the Al13 core takes the most sym. icosahedral form with the Li atom occupying the outer 'hollow-site'.
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174Vichare, A.; Kanhere, D. Surface coverage studies of the icosahedron by Li using density based molecular dynamics. Eur. Phys. J. D 1998, 4, 89– 94, DOI: 10.1007/s100530050188174https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXnvFOlt7w%253D&md5=1834e202f0fe30a2906466f5bc069eb2Surface coverage studies of the Al13 icosahedron by Li using density based molecular dynamicsVichare, A. M.; Kanhere, D. G.European Physical Journal D: Atomic, Molecular and Optical Physics (1998), 4 (1), 89-94CODEN: EPJDF6; ISSN:1434-6060. (Springer-Verlag)D. based mol. dynamics has been used to investigate the ground state structures of heterogeneous binary clusters Al13Lin; n = 1, 2, 3, 4, 10, 19, 20, 21. Some of these structures have also been investigated by full Kohn-Sham based calcns. Our earlier investigations have shown that in the Al-Li cluster, the ground state configurations are the ones where the Al atoms form a core around which the Li atoms form a "cage". In the present work, we have chosen the well-known Al13 icosahedron as the surface over which we study the evolution of the surface coverage as the no. of Li atoms increases. On the basis of the earlier work, we expect that the Al13Li20 cluster would be the most stable and indeed our simulations do yield such a novel fivefold sym. stable structure formed out of purely metal atoms. This icosahedral substrate is also used to study the coverage of the aluminum surface by lithium atoms. For a small no. of Li atoms, these studies suggest that the Li-Li dimerization is not particularly favored.
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175Chandrachud, P.; Joshi, K.; Kanhere, D. Thermodynamics of carbon-doped Al and Ga clusters: Ab initio molecular dynamics simulations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 76, 235423, DOI: 10.1103/PhysRevB.76.235423175https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtVahtg%253D%253D&md5=0471c7b8a9cddc5cdd1f46f3eaf96a93Thermodynamics of carbon-doped Al and Ga clusters: Ab initio molecular dynamics simulationsChandrachud, Prachi; Joshi, Kavita; Kanhere, D. G.Physical Review B: Condensed Matter and Materials Physics (2007), 76 (23), 235423/1-235423/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We have carried out extensive first principles thermodn. simulations for Al13, Ga13, Al12C, and Ga12C. The results are based on the simulation time of 2.4 ns for each of the clusters, and the heat capacity curves have been calcd. using multiple-histogram technique. Both clusters Al13 and Ga13 show higher than bulk melting temps. Upon doping, there is a substantial redn. in the melting temps. of the host clusters. In the case of Ga, the carbon atom changes the geometry from decahedral to icosahedral. This change in the geometry changes the heat capacity curve significantly, making the solidlike to liquidlike transition sharper. Our results bring out the fact that an impurity can be used to tune the finite temp. properties of small clusters.
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176Charkin, O.; Charkin, D.; Klimenko, N.; Mebel, A. A theoretical study of isomerism in doped aluminum XAl12 clusters (X = B, Al, Ga, C, Si, Ge) with 40 valence electrons. Chem. Phys. Lett. 2002, 365, 494– 504, DOI: 10.1016/S0009-2614(02)01512-9176https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XosVeks7w%253D&md5=0f1c4baf86eec1198bbc9e1fa0ea80bdA theoretical study of isomerism in doped aluminum XAl12 clusters (X = B, Al, Ga, C, Si, Ge) with 40 valence electronsCharkin, O. P.; Charkin, D. O.; Klimenko, N. M.; Mebel, A. M.Chemical Physics Letters (2002), 365 (5,6), 494-504CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)D. functional B3LYP calcns. with the 6-31G* and 6-311+G* basis sets have been employed in order to investigate the structure, vibrational frequencies, relative energies, and vertical ionization potentials of low-lying isomers in the family of doped aluminum clusters XAl12- (X = B, Al, Ga) and XAl12 (X = C, Si, Ge). Isomerization barriers have been also detd. The results are compared with the data of previous similar calcns. for endohedral and exohedral isomers of the alane salts Ln+[Al12H12]2- to analyze similarity and differences between the aluminides and alanes.
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177Wu, C.; Lu, P.; Yu, Z.; Ding, L.; Liu, Y.; Han, L. Structural and electronic properties of neutral clusters Al12X (X = P, As, Sb, and Bi) and their cations. J. Comput. Theor. Nanosci. 2013, 10, 1055– 1060, DOI: 10.1166/jctn.2013.2806177https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpsFGrtL8%253D&md5=acf93e1b305c6e61076cb084daa1045aStructural and electronic properties of neutral clusters Al12X (X = P, As, Sb, and Bi) and their cationsWu, Chengjie; Lu, Pengfei; Yu, Zhongyuan; Ding, Lu; Liu, Yumin; Han, LihongJournal of Computational and Theoretical Nanoscience (2013), 10 (5), 1055-1060CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)The structural and electronic properties of neutral clusters Al12X (X = P, As, Sb, and Bi) and their cations have been investigated within the d. functional theory (DFT) using the generalized gradient approxn. (GGA) for the exchange correlation potential. It is obsd. that the ground states of both neutral and cationic Al12P cluster tend to icosahedral structure, while the equil. geometries of Al12X (X = As, Sb, and Bi), either neutral or cationic clusters, favor the C5v structures with doped atom X occupied a peripheral position. The bonding character has been analyzed by calcg. the Mulliken charges and Al-X distances. We found that charge transfers from Al to doped-X site. Clusters possess same symmetry display a similar trend of DOS. Besides, from the PDOS figures, the s, p, d states of doped X atoms play different roles in Al12X (X = P, As, Sb, and Bi) clusters for their most stable structures.
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178Xie, R.-H.; Bryant, G. W.; Zhao, J.; Kar, T.; Smith, V. H., Jr Tunable optical properties of icosahedral, dodecahedral, and tetrahedral clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 125422, DOI: 10.1103/PhysRevB.71.125422178https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXivFensbo%253D&md5=2da6c6586629f17a8520b948fa7baedeTunable optical properties of icosahedral, dodecahedral, and tetrahedral clustersXie, Rui-Hua; Bryant, Garnett W.; Zhao, Jijun; Kar, Tapas; Smith, Vedene H., Jr.Physical Review B: Condensed Matter and Materials Physics (2005), 71 (12), 125422/1-125422/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using time-dependent d.-functional theory, the authors show that the first singlet excitations of a series of icosahedral, dodecahedral, and tetrahedral clusters are optically forbidden and that their optical absorption gaps and spectral properties are size, shape, and compn. dependent and can be tuned broadly in the UV-visible region. Taking icosahedral clusters Al@Al12 and Al@Pb12 as examples, the authors demonstrate that the optical gaps of icosahedral clusters can be tailored from the UV to near IR by properly doping them with (transition) metals, hydrogen, group VIIB atoms, and org. functional groups. Their study suggests icosahedral, dodecahedral, and tetrahedral clusters are suitable for tunable optical applications.
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179Li, S.; Gong, X. Charge-induced structural changes in Al12C clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 075404, DOI: 10.1103/PhysRevB.70.075404179https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnt1yrsrY%253D&md5=7bd3ecd0ec9a8ea2a0a333181c6e9158Charge-induced structural changes in Al12C clustersLi, S. F.; Gong, X. G.Physical Review B: Condensed Matter and Materials Physics (2004), 70 (7), 075404/1-075404/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The structures of Al12C and Al12C- clusters are studied by using the d. functional theory. We find that the charging on the icosahedral Al12C cluster drives the carbon atom from the center of the cluster to its surface. The optimized ground state structure of Al12C- cluster has a low symmetry, in agreement with exptl. observation.
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180Sun, Q.; Wang, Q.; Yu, J.; Kumar, V.; Kawazoe, Y. Real-space representation of electron localization and shell structure in jelliumlike clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2001, 63, 193408, DOI: 10.1103/PhysRevB.63.193408180https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjt1yqu7s%253D&md5=3beb4bceeaff0ccce09a342a2507f5f7Real-space representation of electron localization and shell structure in jelliumlike clustersSun, Q.; Wang, Q.; Yu, J. Z.; Kumar, V.; Kawazoe, Y.Physical Review B: Condensed Matter and Materials Physics (2001), 63 (19), 193408/1-193408/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Results of first-principles calcns. on pure and doped aluminum clusters are analyzed using the electron localization function (ELF) to obtain a real-space representation of the electronic shell structure. Our results provide a quant. anal. of the bonding nature and localization of charge in jelliumlike metal clusters and show that similar to atoms, ELF reproduces the electronic shell structure of clusters in real space.
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181Wang, B.; Zhao, J.; Shi, D.; Chen, X.; Wang, G. Density-functional study of structural and electronic properties of AlnN (n = 2–12) clusters. Phys. Rev. A: At., Mol., Opt. Phys. 2005, 72, 023204, DOI: 10.1103/PhysRevA.72.023204181https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpvFGhurw%253D&md5=0cca4d9e2cba9e0b721dd26c531ce31eDensity-functional study of structural and electronic properties of AlnN (n=2-12) clustersWang, Baolin; Zhao, Jijun; Shi, Daning; Chen, Xiaoshuang; Wang, GuanghouPhysical Review A: Atomic, Molecular, and Optical Physics (2005), 72 (2, Pt. B), 023204/1-023204/5CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)The lowest energy structures and electronic properties of AlnN (n = 2-12) clusters were studied using d.-functional theory. The equil. geometries of AlnN clusters with up to n = 12 were detd. from a no. of possible structural isomers at each size. The Al7N cluster was found be particularly stable with higher binding energy and larger electronic gap. For all the AlnN clusters studied, we found charge transfers from the Al to N site and co-existence of ionic and covalent bonding characteristics.
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182Molina, B.; Soto, J. R.; Castro, J. J. Stability and nonadiabatic effects of the endohedral clusters X@Al12 (X = B, C, N, Al, Si, P) with 39, 40, and 41 valence electrons. J. Phys. Chem. C 2012, 116, 9290– 9299, DOI: 10.1021/jp3004135182https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xks1Citrk%253D&md5=86df4c4528f69c459f6bb2f172709b05Stability and Nonadiabatic Effects of the Endohedral Clusters X@Al12 (X = B, C, N, Al, Si, P) with 39, 40, and 41 Valence ElectronsMolina, Bertha; Soto, Jorge R.; Castro, Jorge J.Journal of Physical Chemistry C (2012), 116 (16), 9290-9299CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Metallic nanoclusters, with 1 electron or hole difference from closed shell, might end up in a degenerate state undergoing a Jahn-Teller distortion as a result of nonadiabatic effects, which are a manifestation of the electron-vibron coupling. Here, the authors report a theor. study on the stability and nonadiabaticity of the neutral and charged endohedral clusters X@Al12 (X = B, C, N, Al, Si, P) around icosahedral symmetry, for 39, 40, and 41 valence electrons. The nonadiabatic effects are evaluated through the Jahn-Teller gain for the distorted cluster and their effect on the calcd. electronic d. of states is analyzed. For the 40 electron valence systems, the authors present the full vibrational spectra. Results are discussed within the framework of the superatom model, and show that not all systems are well described by the spherical jellium model and that nonadiabaticity is better represented by ellipsoidal models. The authors present a detail discussion of the Al13-1 electron detachment process and show how, through a comparison with available exptl. photoelectron spectroscopy data, the nonadiabaticity can be estd.
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183Jimenez-Izal, E.; Moreno, D.; Mercero, J. M.; Matxain, J. M.; Audiffred, M.; Merino, G.; Ugalde, J. M. Doped aluminum cluster anions: size matters. J. Phys. Chem. A 2014, 118, 4309– 4314, DOI: 10.1021/jp501496b183https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXotFCqs7o%253D&md5=cdbe74d3e74fdc64269d492da5e5fc4aDoped Aluminum Cluster Anions: Size MattersJimenez-Izal, Elisa; Moreno, Diego; Mercero, Jose M.; Matxain, Jon M.; Audiffred, Martha; Merino, Gabriel; Ugalde, Jesus M.Journal of Physical Chemistry A (2014), 118 (24), 4309-4314CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The global min. of the cluster anions with the generic chem. formula (XAl12)2-, where X = Be, Mg, Ca, Sr, Ba, and Zn, are detd. by an extensive search of their potential energy surfaces using the Gradient Embedded Genetic Algorithm (GEGA). All the characterized global min. have an icosahedral-like structure, resembling that of the Al13- cluster. These cages comprise closed-shell electronic configurations with 40 electrons, therefore, in accordance to the jellium model, they are predicted to be highly stable and amenable to exptl. detection. The two preferred sites for the dopant species, at the center and at surface of the icosahedral cage, are stabilized depending on the at. radius of X. Thus, while the small dopants (X = Be, Zn) sit preferably at the center of the cage, the preferred site for X = Mg, Ca, Sr, and Ba is at the surface. Since these dianions are not stable towards electron detachment, one Li cation is added in order to yield stable systems. Our computations show that in the global min. form of Li(XAl12)-, the lithium cation, ionically bonded to the Al atoms, does not change the structure of the (XAl12)2- core.
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184Lu, Q.; Jalbout, A.; Luo, Q.; Wan, J.; Wang, G. Theoretical study of hydrogenated Mg, Ca@Al12 clusters. J. Chem. Phys. 2008, 128, 224707, DOI: 10.1063/1.2937144184https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXntFyntLg%253D&md5=bcba057a88dfbfd7c9645adf4e107284Theoretical study of hydrogenated Mg, Ca@Al12 clustersLu, Q. L.; Jalbout, A. F.; Luo, Q. Q.; Wan, J. G.; Wang, G. H.Journal of Chemical Physics (2008), 128 (22), 224707/1-224707/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The studies on the structure and electronic properties of hydrogenated metal embedded Al12 cage clusters have been performed by d. functional theory calcns. We have investigated aluminum cluster hydrides with 12 and 14 hydrogen atoms, resp. Insertion of the Mg, Ca alkali metals remarkably enhances the stability of the aluminum clusters. The hydrogen atom prefers to occupy on-top sites along the surface of the clusters. Mulliken population anal. indicates that significant charge transfer occurs between the Mg and Ca atoms and the Al atoms. Our computations suggest that these clusters appear to be phys. and chem. stable. (c) 2008 American Institute of Physics.
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185Charkin, O.; Klimenko, N.; Charkin, D.; Mebel, A. Isomerism of Doped Aluminum Clusters with the Icosahedral [Al12] Cage. Russ. J. Inorg. Chem. 2005, 50, S17There is no corresponding record for this reference.
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186Charkin, O. P.; Charkin, D. O.; Klimenko, N. M.; Mebel, A. M. A theoretical study of isomerism in doped aluminum MAl12 and MAl12X12 clusters with 40 and 50 valence electrons. Faraday Discuss. 2003, 124, 215– 237, DOI: 10.1039/b211114d186https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmtFertrY%253D&md5=a2618732b80e930b80ac7fa106b65834A theoretical study of isomerism in doped aluminum MAl12 and MAl12X12 clusters with 40 and 50 valence electronsCharkin, Oleg P.; Charkin, Dmitry O.; Klimenko, Nina M.; Mebel, Alexander M.Faraday Discussions (2003), 124 (), 215-237CODEN: FDISE6; ISSN:1359-6640. (Royal Society of Chemistry)Systematic d. functional B3LYP calcns. with the 6-31G* and 6-311+G* basis sets have been employed in order to investigate the structure, vibrational frequencies, relative energies, vertical ionization potentials, and magnetic shielding consts. of endohedral and exohedral isomers in two related families of doped aluminum MAl12 and alane MAl12H12 clusters with 40 and 50 valence electrons, resp. Isomerization barriers have been also detd. Trends in these properties with changing heteroatom M in various series have been followed. The similarities and differences between the aluminides and alanes as well as between the alanes MAl12H12 and related boranes MB12H12 and gallanes MGa12H12 have been scrutinized.
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187Lei, X.-L. Geometrical and electronic properties of neutral and anionic AlnBm (n + m = 13) clusters. J. Cluster Sci. 2011, 22, 159– 172, DOI: 10.1007/s10876-011-0370-x187https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXms12ntLY%253D&md5=558c77846f8a57e8c987e58fb9dda850Geometrical and Electronic Properties of Neutral and Anionic Al n B m (n + m = 13) ClustersLei, Xue-LingJournal of Cluster Science (2011), 22 (2), 159-172CODEN: JCSCEB; ISSN:1040-7278. (Springer)Successively substituted Al13 cluster by B atom both neutral and anionic AlnBm (n + m = 13) clusters have been investigated by the d. functional theory (DFT) at B3LYP/6-31G (d) level, the aim is to understand the evolution of the structural and electronic properties as a function of compn. The results clearly show Al13 cluster as well as Al rich AlnBm clusters prefer the icosahedral geometries while increasing boron contents promote quasi-planar configurations. The geometrical structures of the optimized anionic AlnBm- clusters are very close to those of the neutral clusters with smaller structural modifications. Overall, the vertical ionization potential (VIP), the adiabatic electron affinity (AEA), and the energy gaps (Eg) of AlnBm clusters decrease with increasing of substitution. The largest values of second-order energy differences (Δ2E), VIP, and Eg of Al12B cluster indicate it possesses the most stability among all the investigated clusters, which accords to the exptl. results. The simulated photoelectron spectroscopies (PES) of AlnBm- clusters have also been discussed in this article.
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188Sun, W.-M.; Wu, D.; Li, X.-H.; Li, Y.; Chen, J.-H.; Li, C.-Y.; Liu, J.-Y.; Li, Z.-R. Quasi-Chalcogen characteristics of Al12Be: A new member of the three-dimensional periodic table. J. Phys. Chem. C 2016, 120, 2464– 2471, DOI: 10.1021/acs.jpcc.5b11917188https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltlKnug%253D%253D&md5=3bb0bf3deaa8e3733503c21a949f2d3bQuasi-Chalcogen Characteristics of Al12Be: A New Member of the Three-Dimensional Periodic TableSun, Wei-Ming; Wu, Di; Li, Xiang-Hui; Li, Ying; Chen, Jing-Hua; Li, Chun-Yan; Liu, Jia-Yuan; Li, Zhi-RuJournal of Physical Chemistry C (2016), 120 (4), 2464-2471CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The creative concept of superatom brings a new dimension to the conventional periodic table, which has been gradually enriched by both theor. and exptl. research. In this article, we propose a new member, namely, Al12Be, to the superatom family. The amazing similarity between the Al12Be cluster and the chalcogen elements makes the former an excellent superatom counterpart of the latter. In addn., Al12Be exhibits more exothermic first electron affinity (EA) and less endothermic second EA values due to its size advantage over the chalcogen atoms, showing the superatom superiority in this respect. The stable compds. formed between Al12Be and other atoms, such as carbon, beryllium, calcium, and lithium, provide further evidence to support the quasi-chalcogen identity of Al12Be.
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189Ouyang, Y.; Wang, P.; Xiang, P.; Chen, H.; Du, Y. Density-functional theory study of Aln and Aln–1Mg (n = 2–17) clusters. Comput. Theor. Chem. 2012, 984, 68– 75, DOI: 10.1016/j.comptc.2012.01.012189https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjt1Gnsr8%253D&md5=090eae9a2e1d26201bb58387c42f8f19Density-functional theory study of Aln and Aln -1Mg (n = 2-17) clustersOuyang, Yifang; Wang, Peng; Xiang, Peng; Chen, Hongmei; Du, YongComputational & Theoretical Chemistry (2012), 984 (), 68-75CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The equil. geometries, relative stabilities, both vertical and adiabatic of ionization potentials and electron affinities as well electronic properties of Aln and Aln -1Mg (n = 2-17) clusters have been systematically investigated by using B3LYP/6-311G(d). In general, the ground state structures of Aln -1Mg clusters have similar geometries as the host Aln clusters, except for Al4Mg. Starting from n = 7, the Mg atom prefers to stay away from the center of Aln clusters and locate on the site of the corresponding Aln clusters surface. The dissocn. energy of the Aln -1Mg clusters dissoc. into Aln -1 clusters with one Mg atom are lower than those dissoc. into Aln -2Mg clusters with one Al atom, which suggests that the Aln -1Mg clusters are likely to break into Aln -1 clusters with one Mg atom. The results of AEA and VEA, AIP and VIP and second-order difference energy indicate that the Aln -1Mg (n = 3, 5, 7, 9, 11, 13, 15, and 17) clusters are more stable than others, which reveals that the chem. activity of Aln -1Mg clusters are diminished. The electronic structure has been discussed and the results of natural charge population anal. shows that there is a charge transfer from 3s states of Mg atom to 3p states of Al atoms resulting in the strong s-p hybridization.
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190Zhang, J.; Sun, J.; Liu, Y.; Li, J.; Liang, X.; Duan, H. The first-principles study of Al12X (X = Sc-Zn) clusters and their adsorption of H, O and N. AIP Adv. 2016, 6, 075312, DOI: 10.1063/1.4959578190https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1Wmtr7O&md5=da67d4edf9c7c126e6b865bfdfd9f291The first-principles study of Al12X (X = Sc-Zn) clusters and their adsorption of H, O and NZhang, Jingjing; Sun, Jun; Liu, Yanqi; Li, Jiao; Liang, Xiaogang; Duan, HaimingAIP Advances (2016), 6 (7), 075312/1-075312/13CODEN: AAIDBI; ISSN:2158-3226. (American Institute of Physics)Started from the four types 13-atom high-sym. (Ih, Oh, D5h, D3h) close-packed structures and by replacing a 3d transition metal atom in the nonequivalent position, the geometrical and electronic properties of the doped Al12X (X = Sc-Zn) clusters are systematically studied by using the d.-functional theory. Close-packed (icosahedral-like) structures are found to be favorable for the ground state geometries and the degenerate isomers of Al12X (X = Sc, Ti, V, Ni, Cu) clusters. The magnetic moments of the doped Al12X (X = Cr, Mn and Fe) are substantially increased as compared with that of the pure Al13, which are mainly derived from the strong spin splitting of the d electrons of the doped atoms. For the absorption of H, O and N on the close-packed Al12X clusters, it is found that H atom tend to occupy the top or bridge site instead of the hollow site, but the adsorption sites of O and N atom are more complex. O and N are always adsorbed around the doped atom of the doped cluster with the doped atom on the surface and the adsorption energies of O and N on the doped clusters are all enhanced as compared with that on pure Al13, but it is quite different for the adsorption of H, which implies that the influences of the d electrons of the doped atoms on O and N are stronger than that on H. All doped clusters exhibit the same selective sequence of adsorption: O > N > H. (c) 2016 American Institute of Physics.
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191Castro, J.; Soto, J.; Molina, B. Jahn-Teller analysis of the electronic properties of the endohedral clusters M@Al12 (M = B, Al, Ga) and their anions. AIP Conf. Proc. 2011, 1420, 145– 150, DOI: 10.1063/1.3678625191https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XitFGrsrk%253D&md5=ddad6b12f9baa19a763f48583662582aJahn-Teller analysis of the electronic properties of the endohedral clusters MAl12 (M = B, Al, Ga) and their anionsCastro, J. J.; Soto, J. R.; Molina, B.AIP Conference Proceedings (2011), 1420 (Advanced Summer School in Physics), 145-150CODEN: APCPCS; ISSN:0094-243X. (American Institute of Physics)It is well established that several doped aluminum clusters (MAl12), with 40 valence electrons and the dopant M at the center of the icosahedral Al12 cage, present a highly stable icosahedral structure with electronic closed-shell and HOMO-LUMO gap comparable to C60 and Au20. It has also been shown that the 39 valence electrons cluster Al13 could be regarded as a superhalogen superatom, with an electron affinity close to the chlorine atom. However, when an electron is detached from an electronic closed-shell icosahedral system, we end up with a degenerated HOMO state, showing a Jahn-Teller instability, undergoing therefore a structural distortion to remove the electron degeneracy by lowering the symmetry. In this work we perform a Jahn-Teller anal. of the electronic properties of the endohedral clusters MAl12 (M = B, Al, Ga) under the symmetry breaking process, lowering their Ih symmetry to D2h for B and D3d for Al and Ga. We show the necessity of taking into account this symmetry breaking in order to obtain a proper estn. of their electron affinity. This study is based on an all-electron fully relativistic DFT calcn. (c) 2011 American Institute of Physics.
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192Zhao, J.; Liu, B.; Zhai, H.; Zhou, R.; Ni, G.; Xu, Z. Mass spectrometric and first principles study of AlnC– clusters. Solid State Commun. 2002, 122, 543– 547, DOI: 10.1016/S0038-1098(02)00210-7192https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XlvFelsb8%253D&md5=1562fb22fb7b13f17d9672eb6c92b579Mass spectrometric and first principles study of AlnC- clustersZhao, Jijun; Liu, Bingchen; Zhai, Huajin; Zhou, Rufang; Ni, Guoquan; Xu, ZhizhanSolid State Communications (2002), 122 (10), 543-547CODEN: SSCOA4; ISSN:0038-1098. (Elsevier Science Ltd.)The authors study Al-C mixed clusters by using time-of-flight mass spectrum expts. and ab initio calcns. Mass abundance distributions were obtained for anionic Al and Al-C mixed clusters. Besides the known magic Al clusters such as the Al13- and Al23-, the Al7C- cluster is particularly stable among those AlnC- clusters. D. functional calcns. were performed to det. the ground state structures of AlnC- clusters. The authors' results show that the Al7C- is a magic cluster with extremely high stability, which might serve as a building block for cluster-assembled materials.
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193Kumar, V. Ab initio molecular dynamics studies of metal clusters. Bull. Mater. Sci. 1997, 20, 745– 754, DOI: 10.1007/BF02747415193https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXmvFynur4%253D&md5=756dd6dd41e3275b90eb60377498768dAb initio molecular dynamics studies of metal clustersKumar, VijayBulletin of Materials Science (1997), 20 (6), 745-754CODEN: BUMSDW; ISSN:0250-4707. (Indian Academy of Sciences)A review with 32 refs. We present results of our ab-initio mol.-dynamics simulations on the at. and electronic structures of clusters of divalent metals (e.g., aluminum and antimony) which exhibit a range of bonding characteristics (e.g. nonmetal-metal transition, metallic and covalent, resp.). Results of these studies have been used to develop icosahedral Al12X (X = C, Si, and Ge) superatoms with 40 valence electrons which correspond to a filled electronic shell. It is found that the doping leads to a large gain in the binding energy as compared to Al13, suggesting this to be a novel way of developing species for cluster assembled materials. Further studies of adsorption of Li, Si, and Cl atoms on Al7 and Al13 clusters show marked variation in the adsorption behavior of clusters as a function of size and the adsorbate. Silicon reconstructs both the clusters and induces covalency in Al-Al bonds. We discuss the adsorption behavior in terms of the superatom-atom interactions.
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194Kumar, V. Icosahedral symmetry in clusters. Prog. Cryst. Growth Charact. Mater. 1997, 34, 95– 131, DOI: 10.1016/S0960-8974(97)00007-7194https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXjs1GgsL0%253D&md5=b053d9a1161c0e086593b1d2ed507fd7Icosahedral symmetry in clustersKumar, VijayProgress in Crystal Growth and Characterization of Materials (1997), 34 (1-4), 95-131CODEN: PCGMED; ISSN:0960-8974. (Elsevier)A review with 114 refs. First principles calcns. and simulations based on interat. potentials together with exptl. studies of abundance spectrum suggest icosahedral structures to be common for some magic clusters of diverse systems such as rare gases, metals, covalently bonded systems, and water. Close-packing models obtained from pair potentials are shown to be good representations of the structure of rare gas clusters. However, the electronic structure is found to play the important role in the at. structure and related properties of other clusters. Results of recent studies of fullerenes, their derivs. as well as some large icosahedral metal clusters contg. several thousand atoms are also presented. Further results on doped icosahedral clusters are discussed which hold promise for the development of new materials and for understanding the occurrence of icosahedral order in several aluminum alloys.
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195Frisch, M. J.; Trucks, G.; Schlegel, H.; Scuseria, G.; Robb, M.; Cheeseman, J.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. Gaussian 09, Revision D. 01. Gaussian. Inc.: Wallingford, CT 2009, 2, 4There is no corresponding record for this reference.
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196Li, X.; Wu, H.; Wang, X.-B.; Wang, L.-S. S-p hybridization and electron shell structures in aluminum clusters: A photoelectron spectroscopy study. Phys. Rev. Lett. 1998, 81, 1909– 1912, DOI: 10.1103/PhysRevLett.81.1909196https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXls1Wjs74%253D&md5=1814686081ac4111879b1e1bb7e7d039s-p Hybridization and electron shell structures in aluminum clusters: a photoelectron spectroscopy studyLi, Xi; Wu, Hongbin; Wang, Xue-Bin; Wang, Lai-ShengPhysical Review Letters (1998), 81 (9), 1909-1912CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Using photoelectron spectroscopy of size-selected Alx- (x = 1-162) clusters, we studied the electronic structure evolution of Alx and obsd. that the Al 3s- and 3p-derived bands evolve and broaden with cluster size and begin to overlap at Al9. Direct spectroscopic signatures were obtained for electron shell structures with spherical shell closings at Al11-, Al13-, Al19-, Al23-, Al35-, Al37-, Al46, Al52, Al55-, Al56, Al66, and Al73-. The electron shell effect diminishes above Al75 and new spectral features appearing in Alx- (x>100) suggest a possible geometrical packing effect in large clusters.
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197Tsunoyama, H.; Akutsu, M.; Koyasu, K.; Nakajima, A. The stability of binary Al12X nanoclusters (X = Sc and Ti): Superatom or Wade’s polyhedron. J. Phys.: Condens. Matter 2018, 30, 494004, DOI: 10.1088/1361-648X/aaebde197https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXktFCku7s%253D&md5=90847ec291978f6eb92ed6e4ac1e8aceThe stability of binary Al12X nanoclusters (X = Sc and Ti): superatom or Wade's polyhedronTsunoyama, Hironori; Akutsu, Minoru; Koyasu, Kiichirou; Nakajima, AtsushiJournal of Physics: Condensed Matter (2018), 30 (49), 494004/1-494004/7CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Binary nanoclusters (NCs) exhibit strong potential as building blocks for tailor-made scientific materials based on the precise tuning of their electron countings and spin states along with the synergistic effects that originate from the constituent elements. Herein, we studied the electronic and geometric structures of transition metal (TM) doped aluminum (Al) Al12X NCs (X = Sc and Ti), which are binary systems that extend from representative superatom Al13- anions. On the basis of the photoelectron spectroscopy (PES) and d. functional theory (DFT) calcns., Al12X anion and neutral structures are characterized as vertex-replaced icosahedron. The highly stable exohedral Al12X icosahedron is described based on an electron counting rule derived from the coupling of Wade-Mingos' rule and the jellium model.
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198Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 59, 1758– 1775, DOI: 10.1103/PhysRevB.59.1758198https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXkt12nug%253D%253D&md5=78a73e92a93f995982fc481715729b14From ultrasoft pseudopotentials to the projector augmented-wave methodKresse, G.; Joubert, D.Physical Review B: Condensed Matter and Materials Physics (1999), 59 (3), 1758-1775CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived. The total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addn., crit. tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed-core all-electron methods. These tests include small mols. (H2, H2O, Li2, N2, F2, BF3, SiF4) and several bulk systems (diamond, Si, V, Li, Ca, CaF2, Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
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199Kresse, G.; Furthermuller, J. Effect of Er doping on the electronic structure optical properties of ZnO. Phys. Rev. B 1996, 54, 11169– 11186199https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xms1Whu7Y%253D&md5=9c8f6f298fe5ffe37c2589d3f970a697Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis setKresse, G.; Furthmueller, J.Physical Review B: Condensed Matter (1996), 54 (16), 11169-11186CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The authors present an efficient scheme for calcg. the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrixes will be discussed. This approach is stable, reliable, and minimizes the no. of order Natoms3 operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special "metric" and a special "preconditioning" optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calcns. It will be shown that the no. of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order Natoms2 scaling is found for systems contg. up to 1000 electrons. If we take into account that the no. of k points can be decreased linearly with the system size, the overall scaling can approach Natoms. They have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable.
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200Leskiw, B. D.; Castleman, A. W. The interplay between the electronic structure and reactivity of aluminum clusters: Model systems as building blocks for cluster assembled materials. Chem. Phys. Lett. 2000, 316, 31– 36, DOI: 10.1016/S0009-2614(99)01295-6200https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXltlOjug%253D%253D&md5=d34c409e1f62d6e6cef7bf1f65231963The interplay between the electronic structure and reactivity of aluminum clusters: model systems as building blocks for cluster assembled materialsLeskiw, B. D.; Castleman, A. W.Chemical Physics Letters (2000), 316 (1,2), 31-36CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Reactions of aluminum-carbon cluster anions with oxygen were investigated under well-defined thermal conditions in a fast flow reactor. The resistance of particular species to the etching of oxygen is obsd. and is explained through the predicted shell closings of the Jellium model. The presence of Al7C-, in particular, is compatible with this cluster being a composite Jellium system stabilized by ion-polarizability interactions. This would be the first species of which we are aware that exits as a magic cluster in this context.
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201Sun, Q.; Wang, Q.; Gong, X. G.; Kumar, V.; Kawazoe, Y. Structures and stability of Al7C and Al7N clusters. Eur. Phys. J. D 2002, 18, 77– 81, DOI: 10.1140/e10053-002-0009-4201https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XitFyqu7w%253D&md5=2b8c5a9e1ede71a4f27407ecb6f69ffbStructures and stability of Al7C and Al7N clustersSun, Q.; Wang, Q.; Gong, X. G.; Kumar, V.; Kawazoe, Y.European Physical Journal D: Atomic, Molecular and Optical Physics (2002), 18 (1), 77-81CODEN: EPJDF6; ISSN:1434-6060. (Springer-Verlag)We report results of the at. and electronic structures of Al7C cluster using ab initio DFT-MD methods with ultrasoft pseudopotentials and generalized gradient approxn. The lowest energy structure was found to be the one in which carbon atom occupies an interstitial position in Al7 cluster. The recent observation of magic behavior of Al7C- cluster is due to a large HOMO-LUMO gap which makes Al7C- chem. inert. These results led us to the finding of a new neutral magic cluster, Al7N, which has the same no. of valence electrons as in Al7C- and a large HOMO-LUMO gap of 1.99 eV. Calcns. were carried out on (Al7N)2 to study interactions between magic clusters.
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202Bai, Q.; Song, B.; Hou, J.; He, P. First principles study of structural and electronic properties of AlnN (N = 1–19) clusters. Phys. Lett. A 2008, 372, 4545– 4552, DOI: 10.1016/j.physleta.2008.03.067202https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmsFelsro%253D&md5=5e87179040db258498c89db99b9248ecFirst principles study of structural and electronic properties of AlnN (n = 1-19) clustersBai, Qiugui; Song, Bin; Hou, Jinyu; He, PimoPhysics Letters A (2008), 372 (25), 4545-4552CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The structural and electronic properties of AlnN clusters were calcd. by the DFT-GGA method. The N atom tends to occupy an inside position for n ≤ 10 , but prefers a peripheral position with a bulk-like coordination for n > 10. As cluster size increases, an icosahedral-like motif emerges; the cluster grows by capping N and extra Al atoms on the Al13 icosahedron. Al3N and Al7N exhibit particularly high stability. The Al-N bonds may simultaneously possess ionic and covalent characteristics. The calcd. HOMO-LUMO gaps exhibit odd-even oscillations as n increases. The vertical ionization potential of the clusters tends to decrease with n increasing, while the vertical electron affinity shows the opposite trend.
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203Averkiev, B. B.; Call, S.; Boldyrev, A. I.; Wang, L.-M.; Huang, W.; Wang, L.-S. Photoelectron spectroscopy and Ab initio study of the structure and bonding of Al7N- and Al7N. J. Phys. Chem. A 2008, 112, 1873– 1879, DOI: 10.1021/jp7106236203https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtFylsbw%253D&md5=3ef95b0a8f78164082c6216075d4f657Photoelectron Spectroscopy and Ab Initio Study of the Structure and Bonding of Al7N- and Al7NAverkiev, Boris B.; Call, Seth; Boldyrev, Alexander I.; Wang, Lei-Ming; Huang, Wei; Wang, Lai-ShengJournal of Physical Chemistry A (2008), 112 (9), 1873-1879CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The electronic and geometrical structures of Al7N- are studied using photoelectron spectroscopy and ab initio calcns. Photoelectron spectra of Al7N- were obtained at 3 photon energies with 6 resolved spectral features at 193 nm. The spectral features of Al7N- are relatively broad, in particular for the ground state transition, indicating a large geometrical change from the ground state of Al7N- to that of Al7N. The ground state vertical detachment energy is 2.71 eV, whereas only an upper limit of ∼1.9 eV can be estd. for the ground state adiabatic detachment energy due to the broad detachment band. Global min. searches for A7N- and Al7N are performed using several theor. methods. Vertical electron detachment energies are calcd. using 3 different methods for the lowest energy structure and compared with the exptl. data. Calcd. results are in excellent agreement with the exptl. data. The global min. structure of Al7N- possesses C3v symmetry, which can be viewed as an Al atom capping a face of a N-centered Al6N octahedron. In the ground state of Al7N, the capping Al atom is pushed inward with the 3 adjacent Al-Al distances being stretched outward. Even though Al7N still possesses C3v symmetry, it is better viewed as a N-coordinated by 7 Al atoms in a cage-like structure. The chem. bonding in Al7N- is discussed from MO and natural bond anal.
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204Kumar, V. Chemical compositions at alloy surfaces. Phys. Rev. B: Condens. Matter Mater. Phys. 1981, 23, 3756– 3764, DOI: 10.1103/PhysRevB.23.3756204https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXhvVWhtL4%253D&md5=656d077cea1c42299b63c5a82b74fac1Chemical compositions at alloy surfacesKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (1981), 23 (8), 3756-64CODEN: PRBMDO; ISSN:0163-1829.A quasichem. formulation for chem. compn. at the surfaces of nonregular solid solns. is presented and applied to Ag-Au and Cu-Ni alloys. The results are compared with the existing exptl. values. It is obsd. that the use of the surface-energy data instead of the heat of vaporization gives good agreement with the expts. Surface relaxation effects are taken into account. The free energy of segregation is calcd. for several layers. The surface short-range order parameters are found to be quite different from the bulk values.
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205Kumar, V. Segregation at alloy surfaces. Surf. Sci. 1979, 84, L231– L234, DOI: 10.1016/0039-6028(79)90294-2205https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE1MXks1eisbY%253D&md5=698ef56ec5059bd56a710db735a5a712Segregation at alloy surfacesKumar, VijaySurface Science (1979), 84 (1), L231-L234CODEN: SUSCAS; ISSN:0039-6028.A theory is presented for segregation at alloy surfaces, where both the bond breaking and strain theories have been combined into one. The formulation can be applied to alloys of any concn. In addn., some ideas are described which should be considered while dealing with polycryst. samples. Good agreement is obtained with AES data on a Ni-Au system.
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206Guerra, C. F.; Snijders, J.; te Velde, G. t.; Baerends, E. Towards an order-N DFT method. Theor. Chem. Acc. 1998, 99, 391– 403, DOI: 10.1007/s002140050353206https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntl2lsL4%253D&md5=fbb6cec807384e9556f98d0485975efcTowards an order-N DFT methodGuerra, C. Fonseca; Snijders, J. G.; Te Velde, G.; Baerends, E. J.Theoretical Chemistry Accounts (1998), 99 (6), 391-403CODEN: TCACFW; ISSN:1432-881X. (Springer-Verlag)One of the most important steps in a Kohn-Sham (KS) type d. functional theory calcn. is the construction of the matrix of the KS operator (the Fock matrix). It is desirable to develop an algorithm for this step that scales linearly with system size. We discuss attempts to achieve linear scaling for the calcn. of the matrix elements of the exchange-correlation and Coulomb potentials within a particular implementation (the Amsterdam d. functional, ADF, code) of the KS method. In the ADF scheme the matrix elements are completely detd. by 3D numerical integration, the value of the potentials in each grid point being detd. with the help of an auxiliary function representation of the electronic d. Nearly linear scaling for building the total Fock matrix is demonstrated for systems of intermediate size (in the order of 1000 atoms). For larger systems further development is desirable for the treatment of the Coulomb potential.
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207Te Velde, G. t.; Bickelhaupt, F. M.; Baerends, E. J.; Fonseca Guerra, C.; van Gisbergen, S. J.; Snijders, J. G.; Ziegler, T. Chemistry with ADF. J. Comput. Chem. 2001, 22, 931– 967, DOI: 10.1002/jcc.1056207https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXjtlGntrw%253D&md5=314e7e942de9b28e664afc5adb2f574fChemistry with ADFTe Velde, G.; Bickelhaupt, F. M.; Baerends, E. J.; Fonseca Guerra, C.; Van Gisbergen, S. J. A.; Snijders, J. G.; Ziegler, T.Journal of Computational Chemistry (2001), 22 (9), 931-967CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)A review with 241 refs. We present the theor. and tech. foundations of the Amsterdam D. Functional (ADF) program with a survey of the characteristics of the code (numerical integration, d. fitting for the Coulomb potential, and STO basis functions). Recent developments enhance the efficiency of ADF (e.g., parallelization, near order-N scaling, QM/MM) and its functionality (e.g., NMR chem. shifts, COSMO solvent effects, ZORA relativistic method, excitation energies, frequency-dependent (hyper)polarizabilities, at. VDD charges). In the Applications section we discuss the phys. model of the electronic structure and the chem. bond, i.e., the Kohn-Sham MO (MO) theory, and illustrate the power of the Kohn-Sham MO model in conjunction with the ADF-typical fragment approach to quant. understand and predict chem. phenomena. We review the "Activation-strain TS interaction" (ATS) model of chem. reactivity as a conceptual framework for understanding how activation barriers of various types of (competing) reaction mechanisms arise and how they may be controlled, for example, in org. chem. or homogeneous catalysis. Finally, we include a brief discussion of exemplary applications in the field of biochem. (structure and bonding of DNA) and of time-dependent d. functional theory (TDDFT) to indicate how this development further reinforces the ADF tools for the anal. of chem. phenomena.
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208Sharma, H.; Garg, I.; Dharamvir, K.; Jindal, V. Ab Initio Study of Structural and Electronic Properties of AlnN (n = 1–22) Clusters. J. Comput. Theor. Nanosci. 2010, 7, 2297– 2307, DOI: 10.1166/jctn.2010.1611208https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtF2murzI&md5=6d4ac2262d3a35e37e3040a39cffb277Ab initio study of structural and electronic properties of AlnN (n = 1-22) clustersSharma, Hitesh; Garg, Isha; Dharamvir, Keya; Jindal, V. K.Journal of Computational and Theoretical Nanoscience (2010), 7 (11), 2297-2307CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)We have investigated the structural and electronic properties of AlnN clusters for n = 1-22 using ab initio calcns. based on d. functional theory. Nitrogen prefers to stay at inside position for n < 10 and at the surface for n > 10. The binding energy of Aln increases with N addn. However, the binding energy of AlnN cluster shows a steep increase from n = 1-3 and thereafter a gradual decline up to n = 12. For n > 12, the binding energy is found to be nearly const. With N doping, ionization potential (IP) and electron affinity (EA) shows a significant change in pattern w.r.t Aln clusters for n ≤ 10. For n > 10 the pattern is oscillatory which is similar to pure Aln. The electronic properties of Aln are altered to a great extent with HOMO-LUMO gap increasing from 0.1 eV-1.6 eV in Aln to 0.5 eV-3.0 eV in AlnN resp. The HOMO-LUMO gap variation over a wide range could be exploited for tuning optical gap in visible range. The spin multiplicities and the Mulliken charges of AlnN clusters indicate significant charge redistribution in the vicinity of N atom which may lead to change in the chem. reactivity at sites suitable for catalytic activities. The calcd. results are in agreement with existing exptl. and theor. results.
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209Parr, R. G.; Zhou, Z. Absolute hardness: Unifying concept for identifying shells and subshells in nuclei, atoms, molecules, and metallic clusters. Acc. Chem. Res. 1993, 26, 256– 258, DOI: 10.1021/ar00029a005209https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXit1SisLY%253D&md5=790e6db4b9a2907db669f6b6ca350ccbAbsolute hardness: unifying concept for identifying shells and subshells in nuclei, atoms, molecules, and metallic clustersParr, Robert G.; Zhou, ZhongxiangAccounts of Chemical Research (1993), 26 (5), 256-8CODEN: ACHRE4; ISSN:0001-4842.The abs. hardness η, defined as one-half of the second deriv. of the energy with respect to the no. of particles, is related to the shell structure of nuclei, clusters and atoms (η vs. the at. no. Z), to the HOMO-LUMO gap, the difference between the ionization potential and the electron affinity, and to the total d. of states et the Fermi energy in metals.
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210Reveles, J. U.; Khanna, S.; Roach, P.; Castleman, A. Multiple valence superatoms. Proc. Natl. Acad. Sci. U. S. A. 2006, 103, 18405– 18410, DOI: 10.1073/pnas.0608781103210https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xhtlalu7zE&md5=3f9abb91e96626bc2633ebbd1635e091Multiple valence superatomsReveles, J. U.; Khanna, S. N.; Roach, P. J.; Castleman, A. W., Jr.Proceedings of the National Academy of Sciences of the United States of America (2006), 103 (49), 18405-18410CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)We recently demonstrated that, in gas phase clusters contg. aluminum and iodine atoms, an Al13 cluster behaves like a halogen atom, whereas an Al14 cluster exhibits properties analogous to an alk. earth atom. These observations, together with our findings that Al-13 is inert like a rare gas atom, have reinforced the idea that chosen clusters can exhibit chem. behaviors reminiscent of atoms in the periodic table, offering the exciting prospect of a new dimension of the periodic table formed by cluster elements, called superatoms. As the behavior of clusters can be controlled by size and compn., the superatoms offer the potential to create unique compds. with tailored properties. In this article, we provide evidence of an addnl. class of superatoms, namely Al-7, that exhibit multiple valences, like some of the elements in the periodic table, and hence have the potential to form stable compds. when combined with other atoms. These findings support the contention that there should be no limitation in finding clusters, which mimic virtually all members of the periodic table.
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211Chauhan, V.; Singh, A.; Majumder, C.; Sen, P. Structural, electronic and magnetic properties of binary transition metal aluminum clusters: Absence of electronic shell structure. J. Phys.: Condens. Matter 2014, 26, 015006, DOI: 10.1088/0953-8984/26/1/015006211https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFejurg%253D&md5=1ea8a7e000929c46fb5da4a4dd5bf377Structural, electronic and magnetic properties of binary transition metal aluminum clusters: absence of electronic shell structureChauhan, Vikas; Singh, Akansha; Majumder, Chiranjib; Sen, PrasenjitJournal of Physics: Condensed Matter (2014), 26 (1), 015006/1-015006/8, 8 pp.CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Single Cr, Mn, Fe, Co and Ni doped Al clusters having up to 12 Al atoms are studied using d. functional methods. The global min. of structure for all the clusters are identified, and their relative stability and electronic and magnetic properties are studied. FeAl4 and CoAl3 are found to have enhanced stability and arom. behavior. In contrast to binary transition metal alkali and transition metal alk. earth clusters, spherical shell models cannot describe the electronic structure of transition metal Al clusters.
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212Tam, N. M.; Van Duong, L.; Cuong, N. T.; Nguyen, M. T. Structure, stability, absorption spectra and aromaticity of the singly and doubly silicon doped aluminum clusters AlnSim0/+ with n = 3–16 and m = 1, 2. RSC Adv. 2019, 9, 27208– 27223, DOI: 10.1039/C9RA04004H212https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1ylsLvK&md5=7da3198ca5a4666dc0b895fed03a545cStructure, stability, absorption spectra and aromaticity of the singly and doubly silicon doped aluminum clusters AlnSim0/+ with n = 3-16 and m = 1, 2Tam, Nguyen Minh; Duong, Long Van; Cuong, Ngo Tuan; Nguyen, Minh ThoRSC Advances (2019), 9 (47), 27208-27223CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Structures of the binary AlnSim clusters in both neutral and cationic states were investigated using DFT and TD-DFT (B3LYP/6-311+G(d)) and (U)CCSD(T)/cc-pvTZ calcns. Silicon-doped aluminum clusters are characterized by low spin ground states. For small sizes, the Si dopant prefers to be located at vertices having many edges. For larger sizes, the Si atom prefers to be endohedrally doped inside an Aln cage. Relative stability, adiabatic ionization energy and dissocn. energies of each cluster size were evaluated. A characteristic of most Si doped Al clusters is the energetic degeneracy of two lowest-lying isomers. Calcd. results confirm the high stability of the sizes Al4Si2, Al12Si and Al11Si2+ as "magic" clusters, that exhibit 20 or 40 shell electrons and are thermodynamically more stable as compared to their neighbors. Electronic absorption spectra of isoelectronic magic clusters Al13-, Al12Si, and Al11Si2+ that have two pronounced bands corresponding to blue and violet lights, have been rationalized by using the electron shell model. The magnetically included ring c.d. (MICD) analyses suggest that they are also arom. structures as a result of the "magic" 40 shell electrons.
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213Lu, Q.; Wan, J. Sc-coated Si@Al12 as high-capacity hydrogen storage medium. J. Chem. Phys. 2010, 132, 224308, DOI: 10.1063/1.3439689213https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXntlGnu78%253D&md5=902f54feda4a29e764ab86cf724edc56Sc-coated Si@Al12 as high-capacity hydrogen storage mediumLu, Q. L.; Wan, J. G.Journal of Chemical Physics (2010), 132 (22), 224308/1-224308/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)H mols. adsorption and storage in Sc coated Si@Al12 cluster were studied using d. functional theory methods. Sc atoms can bind strongly to the surfaces of Si@Al12 due to the charge transfer between Sc and Si@Al12, and do not suffer from clustering on the substrate. Si@Al12 cluster coated with 3 and 4 Sc atoms can adsorb 16 and 18 H2 mols. with a binding energy of 0.28-0.63 eV/H2, corresponding to H storage capacity of 6.0 and 6.3%, resp. The stable Si@Al12 can be applied as one of candidates for H storage materials at ambient conditions. (c) 2010 American Institute of Physics.
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214Lochan, R. C.; Head-Gordon, M. Computational studies of molecular hydrogen binding affinities: The role of dispersion forces, electrostatics, and orbital interactions. Phys. Chem. Chem. Phys. 2006, 8, 1357– 1370, DOI: 10.1039/b515409j214https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XitlKmurw%253D&md5=b872b2e4491c7ea0ebdde9b587195d02Computational studies of molecular hydrogen binding affinities: The role of dispersion forces, electrostatics, and orbital interactionsLochan, Rohini C.; Head-Gordon, MartinPhysical Chemistry Chemical Physics (2006), 8 (12), 1357-1370CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Intermol. interactions between H2 and ligands, metals, and metal-ligand complexes det. the binding affinities of potential H storage materials (HSM), and thus their potential for practical use. A brief survey of current activity on HSM is given. The key issue of binding strengths is examd. from a basic perspective by surveying the distinct classes of interactions (dispersion, electrostatics, orbital interactions) in a general way and then in the context of calcd. binding affinities for a range of model systems.
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215Gong, X. G.; Kumar, V. Metallic coverings of calcium on C60. Chem. Phys. Lett. 2001, 334, 238– 244, DOI: 10.1016/S0009-2614(00)01386-5215https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXhtFejtr4%253D&md5=7e4591d3d77483a055c532db7b2c4a71Metallic coverings of calcium on C60Gong, X. G.; Kumar, V.Chemical Physics Letters (2001), 334 (4,5,6), 238-244CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)We present results of the electronic structure and stability of calcium coverings on C60 using a LCAO and the local d. functional approxn. Calcns. on CaxC60 with x = 12, 20 and 32 show partial charge transfer from calcium atoms to C60 and hybridization of the calcium and fullerene states. This leads to (i) a large binding energy of Ca on C60 which decreases with an increasing coverage and (ii) formation of a metallic shell on C60. The large abundance of the Ca32C60 complex is shown to be due to geometric factors in agreement with expts.
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216Yoon, M.; Yang, S.; Hicke, C.; Wang, E.; Geohegan, D.; Zhang, Z. Calcium as the superior coating metal in functionalization of carbon fullerenes for high-capacity hydrogen storage. Phys. Rev. Lett. 2008, 100, 206806, DOI: 10.1103/PhysRevLett.100.206806216https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtlSlsrc%253D&md5=3f9088c8fe7ce4f161e0acbb5c8563d3Calcium as the superior coating metal in functionalization of carbon fullerenes for high-capacity hydrogen storageYoon, Mina; Yang, Shenyuan; Hicke, Christian; Wang, Enge; Geohegan, David; Zhang, ZhenyuPhysical Review Letters (2008), 100 (20), 206806/1-206806/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We explore theor. the feasibility of functionalizing carbon nanostructures for hydrogen storage, focusing on the coating of C60 fullerenes with light alk.-earth metals. Our first-principles d. functional theory studies show that both Ca and Sr can bind strongly to the C60 surface, and highly prefer monolayer coating, thereby explaining existing exptl. observations. The strong binding is attributed to an intriguing charge transfer mechanism involving the empty d levels of the metal elements. The charge redistribution, in turn, gives rise to elec. fields surrounding the coated fullerenes, which can now function as ideal mol. hydrogen attractors. With a hydrogen uptake of >8.4 wt % on Ca32C60, Ca is superior to all the recently suggested metal coating elements.
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217Reyhani, A.; Mortazavi, S.; Mirershadi, S.; Moshfegh, A.; Parvin, P.; Golikand, A. N. Hydrogen storage in decorated multiwalled carbon nanotubes by Ca, Co, Fe, Ni, and Pd nanoparticles under ambient conditions. J. Phys. Chem. C 2011, 115, 6994– 7001, DOI: 10.1021/jp108797p217https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjsVClu70%253D&md5=ac67a3bc8348e4286c51a8ad2ab6f1a2Hydrogen Storage in Decorated Multiwalled Carbon Nanotubes by Ca, Co, Fe, Ni, and Pd Nanoparticles under Ambient ConditionsReyhani, A.; Mortazavi, S. Z.; Mirershadi, S.; Moshfegh, A. Z.; Parvin, P.; Golikand, A. NozadJournal of Physical Chemistry C (2011), 115 (14), 6994-7001CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We report a study on hydrogen storage in Ca, Co, Fe, Ni, and Pd decorated multiwalled carbon nanotubes (MWCNTs) by using two techniques: volumetric and electrochem. The results showed that hydrogen mols. are adsorbed on the defect sites and transported to the spaces between adjacent carbon via diffusion through both defect sites and opened tips into the layers. Hydrogen storage capacity can be improved in the decorated MWCNT by Co, Fe, Ni, and Ca metals in two approaches: (i) H2 adsorption via Kubas interaction and (ii) dissocn. of H2 mols. on the metal particles. The results reveal that Pd are more effective catalyst for hydrogen storage process. It was found that dissocn. of H2 occurs on the Pd particle, and hydrogen atoms are entered into the spaces between adjacent carbon layers. They create loosely bonds of CHx species and Pd-C-Hx complex which can be decompd. easily at lower temps. as compared to C-H chem. bonds.
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218Sun, Q.; Wang, Q.; Jena, P.; Kawazoe, Y. Clustering of Ti on a C60 surface and its effect on hydrogen storage. J. Am. Chem. Soc. 2005, 127, 14582– 14583, DOI: 10.1021/ja0550125218https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVGqs7fL&md5=1199dab8a8e9f7785b44a3b1acd73e3aClustering of Ti on a C60 Surface and Its Effect on Hydrogen StorageSun, Qiang; Wang, Qian; Jena, Puru; Kawazoe, YoshiyukiJournal of the American Chemical Society (2005), 127 (42), 14582-14583CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Pure carbon nanotubes and fullerenes are unsuitable as high-capacity (large-gravimetric-d.) hydrogen storage materials because of the weak bonding of hydrogen mols. to the carbon frame. However, coating of such carbon nanostructures with isolated transition metal atoms (e.g., Sc and Ti) can increase the binding energy of hydrogen and lead to high hydrogen storage capacity (e.g., up to 8 wt.% hydrogen). However, this prediction depends on the assumption that the metal atoms coated on the fullerene surface will remain isolated. Using first-principles calcns. based on d. functional theory, it was shown that Ti atoms would prefer to cluster on the C surface, which can significantly alter the nature of hydrogen bonding, thus affecting not only the amt. of stored hydrogen but also their thermodn. and kinetics. Calcns. were made for such fullerides as TiC60 and Ti2C60. Clustering of Ti atoms on the surface, as shown by a T12-cluster on the C60 surface, decreased the hydrogen storage capacity, by removing bonding sites of internal Ti atoms within the cluster.
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219Delley, B. An all-electron numerical method for solving the local density functional for polyatomic molecules. J. Chem. Phys. 1990, 92, 508– 517, DOI: 10.1063/1.458452219https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXht1Ggu7o%253D&md5=89fa4df9819ef5714d3a872cc2e88bc8An all-electron numerical method for solving the local density functional for polyatomic moleculesDelley, B.Journal of Chemical Physics (1990), 92 (1), 508-17CODEN: JCPSA6; ISSN:0021-9606.A method for accurate and efficient local-d.-functional calcns. (LDF) on mols. is described. The method, Dmol for short, uses fast convergent three-dimensional numerical integrations to calc. the matrix elements occurring in the Ritz variation method. The flexibility of the integration technique opens the ways to use the most efficient variational basis sets. A practical choice of numerical basis sets is shown with a built-in capability to reach the LDF dissocn. limit exactly. Dmol includes also an efficient, exact approach for calcg. the electrostatic potential. Results on small mols. illustrate present accuracy and error properties of the method. Computational effort for this method grows to leading order with the cube of the mol. size. Except for the soln. of an algebraic eigenvalue problem, the method can be refined to quadratic growth for large mols.
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220Gong, X.; Kumar, V. Electronic structure and relative stability of icosahedral Al–transition-metal clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 50, 17701– 17704, DOI: 10.1103/PhysRevB.50.17701220https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXivVyltr4%253D&md5=a0ae49ff79f4d8265133f66892433ef3Electronic structure and relative stability of icosahedral Al-transition-metal clustersGong, X. G.; Kumar, VijayPhysical Review B: Condensed Matter (1994), 50 (23), 17701-4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The electronic structure and relative stability of icosahedral Al12M (M = transition metal) clusters have been studied using the d. functional theory within the local spin d. approxn. The calcns. predict large binding energies for clusters with M atom in the middle of a d-series in agreement with the occurrence of Al12W phase in these alloys and provide an insight into the understanding of the stability of Al-M quasicrystals.
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221Pearson, W. B. The crystal chemistry and physics of metals and alloys; Wiley-Interscience: New York, 1972.There is no corresponding record for this reference.
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222Lu, Q. L.; Chen, L. L.; Wan, J. G.; Wang, G. H. First principles studies on the interaction of O2 with X@Al12 (X = Al-, P+, C, Si) clusters. J. Comput. Chem. 2010, 31, 2804– 2809, DOI: 10.1002/jcc.21573222https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFGqtbzK&md5=321f62a8618d0608a39e67cfd6a5d6ceFirst principles studies on the interaction of O2 with X@Al12 (X = Al-, P+, C, Si) clustersLu, Qi liang; Chen, Li Li; Wan, Jian Guo; Wang, Guang HouJournal of Computational Chemistry (2010), 31 (15), 2804-2809CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)The interaction of O2 with the doped icosahedral X@Al12 (X = Al-, P+, C, Si) clusters with 40 valence electrons were investigated using d. functional theory methods. A different behavior exhibited between Al13- and X@Al12 (X = P+, C, Si) when they interact with O2. The dissocn. of O2 on Al13- is strongly dependent on spin state of oxygen mol. But X@Al12 (X = P+, C, and Si) is not the case. The transform of spin moment from O2 to Al13- is much faster. Small molecularly binding energy and relatively high energy barrier show that these clusters are all reluctant reacts with the ground state O2. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010.
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223Zhao, J.-Y.; Zhao, F.-Q.; Xu, S.-Y.; Ju, X.-H. DFT studies on doping effect of Al12X: adsorption and dissociation of H2O on Al12X clusters. J. Phys. Chem. A 2013, 117, 2213– 2222, DOI: 10.1021/jp309422p223https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXivVyhsLc%253D&md5=007263c993d19a97ff339c4c0bd242b4DFT Studies on Doping Effect of Al12X: Adsorption and Dissociation of H2O on Al12X ClustersZhao, Jian-Ying; Zhao, Feng-Qi; Xu, Si-Yu; Ju, Xue-HaiJournal of Physical Chemistry A (2013), 117 (10), 2213-2222CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The adsorption and reaction of H2O mol. on neutral X-centered icosahedronal Al12X clusters (X = Al, Mg, Zn, Ga, Ni, Fe, B, C, Si, P) were investigated by PW91, PBE, and PWC methods. Reaction energies and reaction barriers were detd. The spin states and the doped atoms have important influences on the Al12X geometries, d., electronic properties, and energy d. of reaction between Al12X with a single H2O mol. The energies of the neutral X-centered Al12X are lower than that of surface X-replaced Al12X with the exception of Al12Mg. The H2O dissocn. on the Al12X (X = Mg, Zn, Ga, Ni, Fe) clusters have relatively low activation barriers, but large activation barriers for Al12X (X = B, C, Si, P). The activation barrier of water dissocn. on the singlet Al12Fe cluster is the lowest, whereas the highest barrier is with the Al12C. The reaction of H2O with Al12Fe is the most exothermic. The center-Fe atom can move out to the surface after the adsorption and dissocn. of H2O with an energy barrier of 172 kJ/mol. The results showed that the water dissocn. on the Al12X cluster can be tuned by controllable X doping.
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224Zhao, J.-Y.; Zhao, F.-Q.; Xu, S.-Y.; Ju, X.-H. Theoretical study of the geometries and decomposition energies of CO2 on Al12X: Doping effect of Al12X. J. Mol. Graphics Modell. 2014, 48, 9– 17, DOI: 10.1016/j.jmgm.2013.11.002224https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFGrsLs%253D&md5=8a87ee9c1c301e776deb6d15ea194e6eTheoretical study of the geometries and decomposition energies of CO2 on Al12X: Doping effect of Al12XZhao, Jian-Ying; Zhao, Feng-Qi; Xu, Si-Yu; Ju, Xue-HaiJournal of Molecular Graphics & Modelling (2014), 48 (), 9-17CODEN: JMGMFI; ISSN:1093-3263. (Elsevier Ltd.)The adsorption and decompn. of CO2 mol. on X-centered icosahedronal Al12X clusters (doping atom X = Al, Be, Zn, Fe, Ni, Cu, B, C, Si, P) were investigated by the DFT methods of PW91 and PWC. Adsorption energies, chemisorption energies and energy barriers of physic- and chemisorptions for CO2 were detd. It was found that the doping atoms and spin states have important influences on the Al12X geometries, electronic properties and energies of the adsorption processes. CO2 chemisorption on the Al12C cluster is energetically and kinetically unfavorable. CO2 decompn. on the metallic doping Al12X (X = Fe, Ni, Cu) clusters has relatively low energy barriers. On contrary, the barriers are large when X = B, C, Si and P. The energy barriers for CO2 chemisorption and decompn. on the Al12Fe cluster are 5.23 kJ/mol and 38.53 kJ/mol, resp. These values are the lowest among all the clusters being discussed. The adsorption and decompn. of CO2 on the Al12X cluster can be tuned by X doping.
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225Zhao, J.-Y.; Zhang, Y.; Zhao, F.-Q.; Ju, X.-H. Adsorption of carbon dioxide on Al12X clusters studied by density functional theory: Effect of charge and doping. J. Phys. Chem. A 2013, 117, 12519– 12528, DOI: 10.1021/jp405934w225https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslaqu7zJ&md5=759fc07b1ef949a1533b114c737fa3b2Adsorption of Carbon Dioxide on Al12X Clusters Studied by Density Functional Theory: Effect of Charge and DopingZhao, Jian-Ying; Zhang, Yu; Zhao, Feng-Qi; Ju, Xue-HaiJournal of Physical Chemistry A (2013), 117 (47), 12519-12528CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The adsorption of a CO2 mol. on neutral and charged X-centered icosahedron Al12X±z clusters (X = Al, Be, Zn, Ni, Cu, B, P; z = 0, 1) was studied by the d. functional PW91 and PWC methods. Optimized configurations corresponding to physisorption and chemisorption of CO2 were identified. The adsorption energies, activation barriers, and binding energies involving both the physisorption (Al12X±z·CO2-I) and chemisorption (Al12X±z·CO2-II) for CO2 were detd. The chemisorption of a CO2 mol. on the Al12X clusters (X is a metallic doping element) requires relatively low activation barriers. The lowest barrier is with the Al12Be cluster. For the Al12X- clusters, the barriers are all higher than those of the neutral analogs. For the Al12X+ clusters, two corresponding configurations are linked by a low-energy barrier, and CO2 mol. chemisorption on the Al12Be+ cluster has the lowest barrier. The adsorption energies are larger than the energy barriers, which facilitates the chemisorption. Carbon dioxide adsorbed on the Al12X±z clusters can be tuned by controllable X doping and the total no. of valence electrons and suggest the potential application of Al12X±z nanostructures for carbon dioxide capture and activation.
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226Jin, P.; Chen, Y.; Zhang, S. B.; Chen, Z. Interactions between Al12X (X = Al, C, N and P) nanoparticles and DNA nucleobases/base pairs: Implications for nanotoxicity. J. Mol. Model. 2012, 18, 559– 568, DOI: 10.1007/s00894-011-1085-5226https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVCjsb8%253D&md5=0343e8e9edd3a00d89f9766f8034b1b1Interactions between Al12X (X = Al, C, N and P) nanoparticles and DNA nucleobases/base pairs: implications for nanotoxicityJin, Peng; Chen, Yongsheng; Zhang, Shengbai B.; Chen, ZhongfangJournal of Molecular Modeling (2012), 18 (2), 559-568CODEN: JMMOFK; ISSN:0948-5023. (Springer)The interactions between neutral Al12X(I h ) (X = Al, C, N and P) nanoparticles and DNA nucleobases, namely adenine (A), thymine (T), guanine (G) and cytosine (C), as well as the Watson-Crick base pairs (BPs) AT and GC, were investigated by means of d. functional theory computations. The Al12X clusters can tightly bind to DNA bases and BPs to form stable complexes with neg. binding Gibbs free energies at room temp., and considerable charge transfers occur between the bases/BPs and the Al12X clusters. These strong interactions, which are also expected for larger Al nanoparticles, may have potentially adverse impacts on the structure and stability of DNA and thus cause its dysfunction.
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227Gong, X.; Chiarotti, G. L.; Parrinello, M.; Tosatti, E. α-gallium: A metallic molecular crystal. Phys. Rev. B: Condens. Matter Mater. Phys. 1991, 43, 14277– 14280, DOI: 10.1103/PhysRevB.43.14277227https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXksFOlt78%253D&md5=da7aff90975e5a8c97726395a0747d85α-Gallium: a metallic molecular crystalGong, X. G.; Chiarotti, Guido L.; Parrinello, M.; Tosatti, E.Physical Review B: Condensed Matter and Materials Physics (1991), 43 (17), 14277-80CODEN: PRBMDO; ISSN:0163-1829.A first-principles theor. study is presented of the at. and electronic structures, and of the zero-temp. phases of Ga. The picture of α-Ga that emerges is of a metallic mol. crystal with a strong Ga2 covalent bond and weaker intermol. forces. The picture is supported in detail by the charge d., the electronic structure, and differential bond stretching under pressure. Anomalous features of α-Ga, such as the Knight shift, anisotropic Fermi-surface effects, and optical absorption find a consistent explanation. Accurate x-ray measurements should reveal the Ga2 covalent bonds.
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228Chacko, S.; Joshi, K.; Kanhere, D.; Blundell, S. Why do gallium clusters have a higher melting point than the bulk?. Phys. Rev. Lett. 2004, 92, 135506, DOI: 10.1103/PhysRevLett.92.135506228https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXivVegurY%253D&md5=b6ab14fe363bf9ba24a694190dd9bf7cWhy Do Gallium Clusters Have a Higher Melting Point than the Bulk?Chacko, S.; Joshi, Kavita; Kanhere, D. G.; Blundell, S. A.Physical Review Letters (2004), 92 (13), 135506/1-135506/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)D. functional mol. dynamical simulations have been performed on Ga17 and Ga13 clusters to understand the recently obsd. higher-than-bulk melting temps. in small gallium clusters [G. A. Breaux et al., Phys. Rev. Lett. 91, 215508 (2003)]. The specific-heat curve, calcd. with the multiple-histogram technique, shows the melting temp. to be well above the bulk m.p. of 303 K, viz., around 650 and 1400 K for Ga17 and Ga13, resp. The higher-than-bulk melting temps. are attributed mainly to the covalent bonding in these clusters, in contrast with the covalent-metallic bonding in the bulk.
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229Henry, D. J. Structures and stability of doped gallium nanoclusters. J. Phys. Chem. C 2012, 116, 24814– 24823, DOI: 10.1021/jp307555r229https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1ent77P&md5=caecb1311bb0bcbed379fc6d074ec273Structures and Stability of Doped Gallium NanoclustersHenry, David J.Journal of Physical Chemistry C (2012), 116 (46), 24814-24823CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The stability and reactivity of metal nanoclusters are critically dependent on the valence electronic configuration of the cluster. Many "magic" electronic configurations are inaccessible for pure trivalent metal clusters. However, doping is one method by which the electronic configuration and properties of a cluster can be significantly modified or even tailored. D. functional theory (DFT-PBE0) is used in this study to investigate the structures, stabilities and electronic properties of doped gallium nanoclusters, Ga12X (X = B, C, N, Al, Si, P, Ga, Ge, and As). In all cases doping of the cluster leads to increased stability relative to Ga13. Stabilization is largely due to electronic contributions, although for many of the clusters the dopant also induces a small increase in the stability of the Ga12 framework. Generally, the endohedrally doped isomers are either lower in energy or close in energy to the isomers with the dopant at the surface of the cluster. Endohedral Ga12C is the most stable cluster and exhibits the most jellium-like orbital structure. Trends in vertical ionization potentials and electron affinities can be explained in terms of the interactions in frontier orbitals and generally adhere to the predictions of the jellium model.
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230Guo, L. Computational investigation of GanAl (n = 1–15) clusters by the density-functional theory. Comput. Mater. Sci. 2009, 45, 951– 958, DOI: 10.1016/j.commatsci.2009.01.001230https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlslClurs%253D&md5=6251a70c909626773825f35e1dbd8cfdComputational investigation of GanAl (n =1-15) clusters by the density-functional theoryGuo, LingComputational Materials Science (2009), 45 (4), 951-958CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)Low-lying equil. geometric structures of aluminum-doped gallium cluster GanAl (n = 1-15) clusters obtained by an all-electron linear combination of AO approach, within spin-polarized d. functional theory, are reported. The binding energy, dissocn. energy, and stability of these clusters are studied with the three-parameter hybrid generalized gradient approxn. (GGA) due to Becke-Lee-Yang-Parr (B3LYP). Ionization potentials, electron affinities, hardness, and static polarizabilities are calcd. for the ground-state structures within the same method. The growth pattern for GanAl (n = 1-15) clusters is Al-substituted Gan + 1 clusters and it keeps the similar frameworks of the most stable Gan + 1 clusters except for Ga8Al and Ga13 Al clusters. The Al atom substituted the surface atom of the Gan + 1 clusters for n < 12. Starting from n = 12, the Al atom completely falls into the center of the Ga-frame. The Al atom substituted the center atom of the Gan + 1 clusters to form the Al-encapsulated Gan geometries for n > 12. The odd-even oscillations from GanAl (n = 5) in the dissocn. energy, the second-order energy differences, the HOMO-LUMO gaps, the ionization potential, the electron affinity, and the hardness are more pronounced. The stability anal. based on the energies clearly shows the clusters from n = 5 with an even no. of valence electrons are more stable than clusters with odd no. of valence electrons.
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231Yuan, G.; Lu, P.; Han, L.; Yu, Z.; Shen, Y.; Zhao, L.; Liu, Y. Structural and electronic properties of neutral clusters Ga12X (X = C, Si, Ge, Sn, and Pb) and their anions from first principles. Phys. B 2011, 406, 3498– 3501, DOI: 10.1016/j.physb.2011.06.034231https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXos1antbk%253D&md5=4a736bcc57ed4abda65dafab6a5ff909Structural and electronic properties of neutral clusters Ga12X (X=C, Si, Ge, Sn, and Pb) and their anions from first principlesYuan, Guifang; Lu, Pengfei; Han, Lihong; Yu, Zhongyuan; Shen, Yue; Zhao, Long; Liu, YuminPhysica B: Condensed Matter (Amsterdam, Netherlands) (2011), 406 (18), 3498-3501CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)The structural and electronic properties of neutral and neg. charged Ga12X (X=C, Si, Ge, Sn, and Pb) clusters are calcd. by the first-principles method. The results show that the most stable symmetry depends on the doped atom rather than the geometry structure. However, the geometry symmetry plays an important role in calcg. the energy gap. In addn., in the anionic clusters, the added electron would reduce the energy gap by about 0.4 eV. As for the d. of states (DOS), clusters with the same symmetry show a similar trend of DOS. The major impact on DOS by adding an electron is the occurrence of relative energy shift.
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232Song, B.; Yao, C.-H.; Cao, P.-L. Density-functional study of structural and electronic properties of GanN (n = 1–19) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 035306, DOI: 10.1103/PhysRevB.74.035306232https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XotFWhs7k%253D&md5=91b578c1ef1e92ead0d44125a9dfc6d1Density-functional study of structural and electronic properties of GanN (n = 1-19) clustersSong, Bin; Yao, Chang-Hong; Cao, Pei-linPhysical Review B: Condensed Matter and Materials Physics (2006), 74 (3), 035306/1-035306/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The lowest-energy geometries and electronic-structure properties were obtained for GanN (n = 1-19) clusters within the d.-functional theory using the generalized gradient approxn. for the exchange-correlation potential. The resulting geometries show that the nitrogen atom tends to occupy an inside position for n ≤ 10, but prefers a peripheral position with a bulk-like coordination beyond n = 10. The stability was investigated by analyzing the binding energy per atom and the second difference in energy. The clusters Ga3N, Ga7N, and Ga15N exhibit particularly higher stability. The bonding properties were analyzed by calcg. the Mulliken charges and Ga-N distances. The N in GanN clusters is less ionic than that in bulk GaN (wurtzite phase). The HOMO-LUMO gap, the vertical ionization potential, and the vertical electron affinity form an even-odd alternating pattern with increasing cluster size. In general, the vertical ionization potential tends to lower as the cluster size increases, while the vertical electron affinity tends to increase as the cluster size increases.
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233Akutsu, M.; Koyasu, K.; Atobe, J.; Miyajima, K.; Mitsui, M.; Nakajima, A. Electronic properties of Si and Ge atoms doped in clusters: InnSi m and InnGem. J. Phys. Chem. A 2007, 111, 573– 577, DOI: 10.1021/jp065921w233https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXjtVWqtQ%253D%253D&md5=a9aa7b25ac66ef14f1388311ccc2993eElectronic Properties of Si and Ge Atoms Doped In Clusters: InnSim and InnGemAkutsu, Minoru; Koyasu, Kiichirou; Atobe, Junko; Miyajima, Ken; Mitsui, Masaaki; Nakajima, AtsushiJournal of Physical Chemistry A (2007), 111 (4), 573-577CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Electronic properties of Si and Ge atom doped In clusters, InnSim and InnGem, were studied by photoionization spectroscopy of the neutrals and photoelectron spectroscopy of the anions. Size dependence of ionization energy and electron affinity for InnSi1 and InnGe1 exhibit pronounced even-odd alternation at cluster sizes of n = 10-16, as compared to those for pure Inn clusters. Symmetry lowering with the doped atom of Si or Ge results in undegeneration of electronic states in the 1d shell formed by monovalent In atoms.
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234Nakajima, A.; Hoshino, K.; Sugioka, T.; Naganuma, T.; Taguwa, T.; Yamada, Y.; Watanabe, K.; Kaya, K. Electronic shell structure of indium-sodium (InnNam) bimetallic clusters examined by their ionization potentials and mass distributions. J. Phys. Chem. 1993, 97, 86– 90, DOI: 10.1021/j100103a016234https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXis1Wiu7g%253D&md5=ada82c1f80a8f482d170e734da17ec67Electronic shell structure of indium-sodium (InnNam) bimetallic clusters examined by their ionization potentials and mass distributionsNakajima, Atsushi; Hoshino, Kuniyoshi; Sugioka, Tsuneyoshi; Naganuma, Takashi; Taguwa, Tetsuya; Yamada, Yoshiyuki; Watanabe, Katsura; Kaya, KojiJournal of Physical Chemistry (1993), 97 (1), 86-90CODEN: JPCHAX; ISSN:0022-3654.Indium-sodium (InnNam) bimetallic clusters were produced by two independent laser vaporization methods. Ionization potentials (IPs) of the InnNam clusters were measured up to m = 2 using a tunable UV laser combined with a time-of-flight (TOF) mass spectrometer. At small sizes (n = 3-15), the ionization potentials decrease by 0.1-0.8 eV with the addn. of Na atoms(s), whereas the IPs of larger Inn (15 ≤ n ≤ 27) clusters do not decrease with Na addn. Moreover, IPs of In7Na1 and In13Na1 clusters are higher than those of In7 and In13, and the IP increments can be explained by electronic shell closings of the 1p (8e) and 2p shell (40 e), where In atoms in the clusters are monovalent and trivalent, resp. The electronic shell structure was also examd. by a magic no. in mass distributions of InnNam- cluster anions; the In12Na3- cluster can be obsd. as magic nos., corresponding to the 2p shell closing. In contrast, no electronic shell structure is obsd. in pure Inn clusters around n = 13. These results indicate that Na atom addn. can induce s/p hybridization in the Inn clusters. We also present mass distributions of aluminum-sodium cluster anions, AlnNam-, whose feature can be understood by the electronic shell model.
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235Liu, Y.; Deng, K.; Yuan, Y.; Chen, X.; Wu, H.; Wang, X. Structural and electronic properties of neutral clusters In12X (X = C, Si, Ge, and Sn) and their anions from first principles. Chem. Phys. Lett. 2009, 469, 321– 324, DOI: 10.1016/j.cplett.2009.01.018235https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1antb4%253D&md5=8ca10cdfe9bf8ff5ed5f3bbac117c75aStructural and electronic properties of neutral clusters In12X (X=C, Si, Ge, and Sn) and their anions from first principlesLiu, Yuzhen; Deng, Kaiming; Yuan, Yongbo; Chen, Xuan; Wu, Haiping; Wang, XinChemical Physics Letters (2009), 469 (4-6), 321-324CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The structural and electronic properties of In12X (X = C, Si, Ge, Sn) and their anions were studied using the d. functional theory at BLYP and B3LYP levels. The equil. geometries of In 12 X (X = Si, Ge, and Sn) and their anions favor the pseudo D 5 h structures, while those of In 12 C and its anion tend to form C s ones. The calcd. adiabatic electron affinities of In 12 Si and In 12 Ge are 2.01 and 2.04 eV, resp., in good agreement with the available exptl. data. The magnetic moments of the ground state In 12 X are all zero, indicating that they have closed shell electronic structures. Thus, indium behaves as a trivalent atom in the clusters.
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236Henning, R. W.; Corbett, J. D. Formation of isolated nickel-centered gallium clusters in Na10Ga10Ni and a 2-D network of gallium octahedra in K2Ga3. Inorg. Chem. 1999, 38, 3883– 3888, DOI: 10.1021/ic990335l236https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXks12htbY%253D&md5=4a5c66fcbd1d20851613d518d80bfbedFormation of Isolated Nickel-Centered Gallium Clusters in Na10Ga10Ni and a 2-D Network of Gallium Octahedra in K2Ga3Henning, Robert W.; Corbett, John D.Inorganic Chemistry (1999), 38 (17), 3883-3888CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Exploration of the Na-Ga-Ni system revealed a new compd. contg. the isolated Ga clusters Ga10Ni10-. Single-crystal x-ray diffraction studies of Na10Ga10Ni (space group Pnma, Z = 12, a 13.908(3), b 28.146(6), c 16.286(4) Å) show it to be isostructural with K10In10Ni. The compd. contains two similar naked Ga clusters as distorted, tetracapped trigonal prismatic units that are centered by Ni. The Na atoms serve to isolate the clusters from each other as well as to provide the cluster with a closed shell configuration of electrons. This is the first isolated Ga cluster in an alkali-metal system that is centered. MO calcns. on the cluster are also reported. The crystal structure of K2Ga3 (space group I4/mmm, Z = 4, a 6.1382(3), c 14.815(1) Å) also is isostructural with A2In3 (A = Rb, Cs). This contains Ga64- octahedra interconnected through the waist atoms into layers ∞2[Ga64-], with octahedra in adjacent layers sitting in the depressions of the first. The K atoms have characteristic roles except for an unusually short K-K contact (3.242(4) Å) across the layer. Magnetic measurements indicate that both phases are diamagnetic and consistent with the Zintl formalism.
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237Sevov, S. C.; Corbett, J. D. Potassium indium zinc compound K8In10Zn: Interstitially-stabilized analogs of early-transition-metal halide clusters. Inorg. Chem. 1993, 32, 1059– 1061, DOI: 10.1021/ic00059a001237https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXhsF2qs7o%253D&md5=ca57c87ab34902a97f6cfde6942a941bPotassium indium zinc compound K8In10Zn: interstitially-stabilized analogs of early-transition-metal halide clustersSevov, Slavi C.; Corbett, John D.Inorganic Chemistry (1993), 32 (7), 1059-61CODEN: INOCAJ; ISSN:0020-1669.K8In10Zn was prepd. by fusion of the elements at 600°. X-ray single crystal anal. shows the structure to consist of Zn encapsulated in a bicapped square antiprism polyhedron of In with ∼D4d symmetry. The Zn atom is nearly equidistant from all In atoms (av. Zn-In = 2.836 Å). The In-In av. bond distance is 3.072 Å, with the In...In distances on the edges of the square faces 0.57 Å longer. The stability of the structure is explained using EHMO calcns. Magnetic susceptibility data was detd. and compared to K8In11.
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238Sevov, S. C.; Corbett, J. D. K10In10Z (Z = Ni, Pd, Pt): Zintl phases containing isolated decaindium clusters centered by transition elements. J. Am. Chem. Soc. 1993, 115, 9089– 9094, DOI: 10.1021/ja00073a026238https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlvFCnurc%253D&md5=523a394105fd463bf34d44bc6939d08dK10In10Z (Z = Ni, Pd, Pt): Zintl phases containing isolated decaindium clusters centered by transition elementsSevov, Slavi C.; Corbett, John D.Journal of the American Chemical Society (1993), 115 (20), 9089-94CODEN: JACSAT; ISSN:0002-7863.The isostructural K10In10Z (Z = Ni, Pd, Pt) are obtained in high yield by slowly cooling the appropriate fused mixt. in welded Ta. They occur as orthorhombic, space group Pnma, Z = 12, with a 15.948(6), 16.043(6), 16.056(3), b 32.565(6), 32.73(1), 32.692(1), and c 18.822(3) , 18.895(5), 18.896(3) Å for the Ni, Pd, and Pt derivs., resp. The structure of K10In10Ni was refined by single crystal means (R = 0.029, Rw = 0.033) and is constructed from close-packed layers of Ni-centered In10 clusters that are sepd. by K ions both within and between the cluster layers. The compds. have large resistivities at room temp. by 2-probe methods and are diamagnetic, with no moments on the transition metals. The geometry of the clusters can be derived from an ideal tetracapped trigonal prism (C3v) of In centered by Z through axial compression along the 3-fold axis and opening of the capped triangular face so as to yield substantially equal Ni-In distances. The clusters are related to Sb73-, etc. Charge-consistent EHMO calcns. show that the Ni-centered cluster has a closed shell with 2n = 20 skeletal electrons, only the s and p orbitals on the interstitial mixing with appropriate cluster orbitals. The d orbitals on Ni do not appear to participate significantly, presumably because they are fully reduced (lie too low) relative to In p (d(In-Ni) ∼ 2.8 Å). This means that Ni, Pd, and Pt behave as quasi-main-group elements.
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239Handschuh, H.; Ganteför, G.; Kessler, B.; Bechthold, P. S.; Eberhardt, W. Stable configurations of carbon clusters: Chains, rings, and fullerenes. Phys. Rev. Lett. 1995, 74, 1095– 1098, DOI: 10.1103/PhysRevLett.74.1095239https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjs1KisLw%253D&md5=6c0ffa3eda1e2034d83adc43e825595dStable configurations of carbon clusters: chains, rings, and fullerenesHandschuh, H.; Gantefoer, G.; Kessler, B.; Bechthold, P. S.; Eberhardt, W.Physical Review Letters (1995), 74 (7), 1095-8CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)A systematic study of the size dependence of the vibrational modes of carbon clusters with 5-70 atoms is presented. The vibrational frequencies are measured using photoelectron spectroscopy of mass-sepd. neg. charged clusters. The clusters are carefully annealed. Only the most stable isomers are present in the beam after the annealing. Obsd. vibrational modes can be assigned to four dominant isomeric structures: linear chains (C5-, C7-, and C9-), monocyclic rings (C10-, C12-, C14-, C16- and C18-), bicyclic rings (C20-, C24-, and C28-), and fullerenes (even n > C30-).
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240Martin, J. M. C28: The smallest stable fullerene?. Chem. Phys. Lett. 1996, 255, 1– 6, DOI: 10.1016/0009-2614(96)00354-5240https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XjsVOnu7c%253D&md5=f23c3e01cd6f9aa2f6fd28ed14745143C28: the smallest stable fullerene?Martin, Jan M. L.Chemical Physics Letters (1996), 255 (1,2,3), 1-6CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)The relative energies of different structures of C28 have been studied by d. functional theory using different exchange-correlation functionals, including two with exact exchange contributions. A fullerene structure with Td symmetry (5A2 state) is found to be by far the most stable structure, followed at 4-6 eV by a graphite sheet fragment and at 5-7 eV by a C14h ring. Other structures lie still higher in energy. An IR spectrum of fingerprint quality has been computed for the fullerene and should enable its exptl. identification.
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241Kroto, H. W. The stability of the fullerenes Cn, with n = 24, 28, 32, 36, 50, 60 and 70. Nature 1987, 329, 529– 531, DOI: 10.1038/329529a0241https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXksFCjsrg%253D&md5=a7bbb6ca1020565379654bce35af2dc3The stability of the fullerenes Cn, with n = 24, 28, 32, 36, 50, 60 and 70Kroto, H. W.Nature (London, United Kingdom) (1987), 329 (6139), 529-31CODEN: NATUAS; ISSN:0028-0836.Empirical chem. and geodesic rules are presented that relate the stability of carbon cage compds. mainly to the disposition of pentagonal rings or directly fused pentagonal ring configurations. The rules yield magic cluster nos. consistent with observation and in particular predict that fullerenes contg. 24, 28, 32, 36, 50, 60, and 70 carbons should have enhanced stability relative to near neighbors. These results support the proposals that closed hollow cages form when carbon nucleates in the vapor phase, and that C60 is a truncated icosahedron.
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242Chen, Z.; Jiao, H.; Bühl, M.; Hirsch, A.; Thiel, W. Theoretical investigation into structures and magnetic properties of smaller fullerenes and their heteroanalogues. Theor. Chem. Acc. 2001, 106, 352– 363, DOI: 10.1007/s002140100284242https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovFOisrw%253D&md5=9e4ca884ccfb2dbda7cc0076d58b265aTheoretical investigation into structures and magnetic properties of smaller fullerenes and their heteroanaloguesChen, Zhongfang; Jiao, Haijun; Buhl, Michael; Hirsch, Andreas; Thiel, WalterTheoretical Chemistry Accounts (2001), 106 (5), 352-363CODEN: TCACFW; ISSN:1432-881X. (Springer-Verlag)The smaller fullerenes, C20, C24, C28, C32, C36, C40 and C50, their hydrogenation products and selected B-, N- and P-doped analogs have been investigated systematically at the B3LYP/6-31G* d. functional level of theory. The degree of spherical electron delocalization is evaluated by using the computed nucleus-independent chem. shifts (NICS) at the cage center and the individual ring centers of interest. The calcd. NMR chem. shifts and the NICS values at the cage center, which can be accessed by endohedral 3He chem. shifts, should provide a basis for further exptl. characterization of these compds.
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243Diener, M. D.; Smith, C. A.; Veirs, D. K. Anaerobic preparation and solvent-free separation of uranium endohedral metallofullerenes. Chem. Mater. 1997, 9, 1773– 1777, DOI: 10.1021/cm960540o243https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXltV2qsbw%253D&md5=8248c84403f03b391f7f80de70153caeAnaerobic Preparation and Solvent-Free Separation of Uranium Endohedral MetallofullerenesDiener, Michael D.; Smith, Coleman A.; Veirs, D. KirkChemistry of Materials (1997), 9 (8), 1773-1777CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)Safe prodn., handling, and sepn. of depleted uranium endohedral metallofullerenes in an oxygen-free environment is demonstrated. Films of C60, C70, and M@C60 are produced by subliming fullerenes from arc-produced soot onto a mass spectrometry target (with ∼1% impurities of higher fullerenes). Also, films consisting of higher fullerenes (empty and full) and mostly devoid of C60 or C70 are made by subliming at higher temps. The temp. of the soot must be uniform and held const. during sublimation to produce high-quality films. M@C60 requires a slightly higher temp. for sublimation than empty C60, the likely result of stronger interactions between M@C60 and its surroundings in the soot.
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244Akiyama, K.; Zhao, Y.; Sueki, K.; Tsukada, K.; Haba, H.; Nagame, Y.; Kodama, T.; Suzuki, S.; Ohtsuki, T.; Sakaguchi, M. Isolation and characterization of light actinide metallofullerenes. J. Am. Chem. Soc. 2001, 123, 181– 182, DOI: 10.1021/ja005618n244https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXoslKjs7w%253D&md5=2cfd64b33ea0bc339d8905d44506ff31Isolation and Characterization of Light Actinide MetallofullerenesAkiyama, Kazuhiko; Zhao, Yuliang; Sueki, Keisuke; Tsukada, Kazuaki; Haba, Hiromitsu; Nagame, Yuichirou; Kodama, Takeshi; Suzuki, Shinzou; Ohtsuki, Tsutomu; Sakaguchi, Masahiko; Kikuchi, Koichi; Katada, Motomi; Nakahara, HiromichiJournal of the American Chemical Society (2001), 123 (1), 181-182CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The arc-discharge prepn. of uranium, neptunium and americium metallofullerenes is reported. The major uranium species formed are U@C82 and U2@C80 which were isolated by a 2-step HPLC sepn. method and identified by TOF/MS measurements. The UV/vis/NIR absorption spectrum for U@C82 is also reported. Similarities in retention times suggest that the major neptunium and americium species are Np@C82 and Am@C82, resp.
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245Dunk, P. W.; Kaiser, N. K.; Mulet-Gas, M.; Rodríguez-Fortea, A.; Poblet, J. M.; Shinohara, H.; Hendrickson, C. L.; Marshall, A. G.; Kroto, H. W. The smallest stable fullerene, M@C28 (M = Ti, Zr, U): Stabilization and growth from carbon vapor. J. Am. Chem. Soc. 2012, 134, 9380– 9389, DOI: 10.1021/ja302398h245https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XlvV2ktLw%253D&md5=09c1e98a07115f099ace15d06c22b0edThe Smallest Stable Fullerene, M@C28 (M = Ti, Zr, U): Stabilization and Growth from Carbon VaporDunk, Paul W.; Kaiser, Nathan K.; Mulet-Gas, Marc; Rodriguez-Fortea, Antonio; Poblet, Josep M.; Shinohara, Hisanori; Hendrickson, Christopher L.; Marshall, Alan G.; Kroto, Harold W.Journal of the American Chemical Society (2012), 134 (22), 9380-9389CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The smallest fullerene to form in condensing carbon vapor has received considerable interest since the discovery of Buckminsterfullerene, C60. Smaller fullerenes remain a largely unexplored class of all-carbon mols. that are predicted to exhibit fascinating properties due to the large degree of curvature and resulting highly pyramidalized carbon atoms in their structures. However, that curvature also renders the smallest fullerenes highly reactive, making them difficult to detect exptl. Gas-phase attempts to investigate the smallest fullerene by stabilization through cage encapsulation of a metal were hindered by the complexity of mass spectra that result from vaporization expts. which include nonfullerene clusters, empty cages, and metallofullerenes. The authors use high-resoln. FT-ICR mass spectrometry to overcome that problem and investigate formation of the smallest fullerene using a pulsed laser vaporization cluster source. Here, the authors report that the C28 fullerene stabilized by encapsulation with an appropriate metal forms directly from carbon vapor as the smallest fullerene under the authors' conditions. Its stabilization is investigated, and M@C28 is formed by a bottom-up growth mechanism and is a precursor to larger metallofullerenes. In fact, apparently the encapsulating metal species may catalyze or nucleate endohedral fullerene formation.
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246Makurin, Y. N.; Sofronov, A. A.; Gusev, A. I.; Ivanovsky, A. L. Electronic structure and chemical stabilization of C28 fullerene. Chem. Phys. 2001, 270, 293– 308, DOI: 10.1016/S0301-0104(01)00342-1246https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXltFyrsbY%253D&md5=88f7826f38f7d6913f1c0f8d4a241c26Electronic structure and chemical stabilization of C28 fullereneMakurin, Y. N.; Sofronov, A. A.; Gusev, A. I.; Ivanovsky, A. L.Chemical Physics (2001), 270 (2), 293-308CODEN: CMPHC2; ISSN:0301-0104. (Elsevier Science B.V.)The ab initio d. functional theory (DFT) method was used to carry out self-consistent calcns. of the electronic structure of "mixed" C28-based fullerenes: (1) heterofullerenes C24N4, C24B4; (2) exohedral complexes C28M4 (M = H, F, Cl, Br); (3) endohedral complexes M28 with 2p-atoms (M = B, C, N, O); and (4) endohedral complexes M28 with 3d-atoms (M = Sc, Ti, V, Cr, Fe, Cu). The electronic structure, charge distributions, chem. bonding and comparative stability in the series of these complexes are analyzed. The optimum chem. stability conditions are met for: (1) C24B4 from the series of heterofullerenes; (2) C28F4 from the series of exocomplexes; (3) B28 from the series of endocomplexes with participation of 2p-atoms; (4) Ti28 from the series of endocomplexes with participation of 3d-atoms. Possible mechanisms of C28 stabilization are discussed depending on the method of functionalization and the type of a "guest" atom.
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247Pederson, M. R.; Laouini, N. Covalent container compound: Empty, endohedral, and exohedral C28 complexes. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 48, 2733– 2737, DOI: 10.1103/PhysRevB.48.2733247https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXmtFWhs7Y%253D&md5=dd7781fc1f0b4d02ce6b9438caaa3d22Covalent container compound: empty, endohedral, and exohedral C28 fullerene complexesPederson, Mark R.; Laouini, NozhaPhysical Review B: Condensed Matter and Materials Physics (1993), 48 (4), 2733-7CODEN: PRBMDO; ISSN:0163-1829.Results are given for quasidynamic local-d. simulations on a small fullerene complex (C28), three endohedral complexes (C28@C, C28@Zr, and C28@Ti), a C atom bound to the corner of the C28 mol., and C28H4. This mol. forms spontaneously from a 29-atom diamond crystallite, and, under proper circumstances, is a covalent container compd. Upon encapsulation of a Zr atom, 12.6 eV of energy is liberated leading to an unreactive closed-shell C28@Zr mol. The open-shell structure of the empty mol. leads to a reactive yet relatively stable building block, which might be useful for synthesis of new metastable forms of carbon-based materials. Electronic structures, ionization energies, electron affinities, equil. geometries, and bare Hubbard U interaction parameters are presented.
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248Jackson, K.; Kaxiras, E.; Pederson, M. R. Electronic states of group-IV endohedral atoms in C28. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 48, 17556– 17561, DOI: 10.1103/PhysRevB.48.17556248https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhtFOisbw%253D&md5=855b8aeba2bdc4f8fceeae251c2f7571Electronic states of group-IV endohedral atoms in C28Jackson, Koblar; Kaxiras, Efthimios; Pederson, Mark R.Physical Review B: Condensed Matter and Materials Physics (1993), 48 (23), 17556-61CODEN: PRBMDO; ISSN:0163-1829.The authors have systematically studied the interaction between the C28 fullerene mol. and the group-IVA endohedral atoms C, Si, Ge, and Sn, using state-of-the-art electronic structure and total-energy calcns. based on d.-functional theory. The authors find no covalent bonding between these atoms and the fullerene cage. The nature of the cage-atom interaction involves charge transfer from the endohedral atom the cage which produces weak, mostly ionic binding. The degree of charge transfer increases with the at. no. of the endohedral atom. By comparing the electronic structure of the group-IVA endohedral cage compds. to Zr@C28 (a group-IVB endohedral), the authors find that the latter bonds strongly to the cage due to covalent interaction between the Zr 4d states and the C28 states. The authors extrapolate the trends found for the group-IV endohedrals to suggest other possibly systems and to provide insight to the stability of the exptl. obsd. U@C28 complex.
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249Guo, T.; Smalley, R. E.; Scuseria, G. E. Ab initio theoretical predictions of C28, C28H4, C28F4,(Ti@C28)H4, and M@C28 (M = Mg, Al, Si, S, Ca, Sc, Ti, Ge, Zr, and Sn). J. Chem. Phys. 1993, 99, 352– 359, DOI: 10.1063/1.465758249https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlvVyqsrk%253D&md5=728482184666009e62dfa22f515bb82fAb initio theoretical predictions of C28 fullerene, hydrofullerene, fluorofullene, and endohedral titanium hydrofullerene (C28, C28H4, C28F4, and (Ti@C28)H4), and C28 endohedral metal or nonmetal fullerenes (M@C28 (M = Mg, Al, Si, S, Ca, Sc, Ti, Ge, Zr, and Sn))Guo, Ting; Smalley, Richard E.; Scuseria, Gustavo E.Journal of Chemical Physics (1993), 99 (1), 352-9CODEN: JCPSA6; ISSN:0021-9606.The authors studied the electronic structures, equil. geometries, and binding energies of the title mols. at the SCF-Hartree-Fock level of theory employing basis sets of double-zeta quality. The empty C28 fullerene has a 5A2 open-shell ground state and behaves as a sort of hollow super-atom with an effective valence of 4, both toward the outside and inside of the carbon cage. The C28H4 and C28F4 should be stable mols. The possibility of simultaneous bonding from the inside and outside of the C28 shell, as in (Ti@C28)H4, is also explored. The binding energy of the M@C28 species is a good indicator of the success in exptl. trapping the metal atoms (M) inside the fullerene cage. Elements with electronegativities smaller than 1.54 should form endohedral fullerenes larger than a min. size which depends on the ionic radius of the trapped atom. This qual. model, correctly reproduces the available exptl. evidence on endohedral fullerenes.
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250Jackson, K.; Kaxiras, E.; Pederson, M. R. Bonding of endohedral atoms in small carbon fullerenes. J. Phys. Chem. 1994, 98, 7805– 7810, DOI: 10.1021/j100083a010250https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXkvFansbY%253D&md5=2f0ce1c9b82ebe30a18a1b5837507539Bonding of Endohedral Atoms in Small Carbon FullerenesJackson, Koblar; Kaxiras, Efthimios; Pederson, Mark R.Journal of Physical Chemistry (1994), 98 (32), 7805-10CODEN: JPCHAX; ISSN:0022-3654.A simple model for understanding the bonding of endohedral atoms in small fullerene cages is presented, which is based on their approx. spherical shape. Previous work has shown that the one-electron wave functions of a fullerene cage can be assigned angular-momentum quantum nos., which describe their overall angular character. These quantum nos. form the basis for approx. selection rules, which govern the bonding with endohedral atoms. With this model, the authors successfully address the very different bonding of various tetravalent elements in C28, and the remarkably strong bonding of U in this small fullerene. The authors also make several specific predictions regarding the stability of other endohedral complexes.
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251Ryzhkov, M. V.; Medvedeva, N. I.; Delley, B. Electronic structures of endohedral fullerenes with scandium, titanium and iron atoms and metal-carbon clusters. Polyhedron 2017, 134, 376– 384, DOI: 10.1016/j.poly.2017.06.032251https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFartrzP&md5=4959355c0c2e3181730c323f17d1cb93Electronic structures of endohedral fullerenes with scandium, titanium and iron atoms and metal-carbon clustersRyzhkov, M. V.; Medvedeva, N. I.; Delley, B.Polyhedron (2017), 134 (), 376-384CODEN: PLYHDE; ISSN:0277-5387. (Elsevier Ltd.)The electronic structures of the endohedral forms of the C28, C40, C60 and C80 fullerenes encapsulating the 3d-atoms Sc, Ti and Fe, and in the case of C80 with M2C2 clusters (M = Sc, Ti, Fe) were investigated using the ab initio Dmol3 method. For the C60 and C80 cages, we found preferable positions of the metal atoms and their carbon clusters near the internal surface of the fullerene shell. The anal. of the formation energy variation and the role of the magnetic state of 3d-atoms is presented.
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252Dunlap, B. I.; Haeberlen, O. D.; Roesch, N. Asymmetric localization of titanium in carbon molecule (C28). J. Phys. Chem. 1992, 96, 9095– 9097, DOI: 10.1021/j100202a003252https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XmsVSis7g%253D&md5=85e82ee77be6c1908215422bfafa6541Asymmetric localization of titanium in carbon molecule (C28)Dunlap, Brett I.; Haeberlen, Oliver D.; Roesch, NotkerJournal of Physical Chemistry (1992), 96 (23), 9095-7CODEN: JPCHAX; ISSN:0022-3654.Linear combination of GTO (LCGTO) local d. functional (LDF) calcns. on the Ti.C28 endohedral fullerene complex suggest that the Ti atom is too small to fill completely the interior vol. of the tetrahedral C28 fullerene; the Ti atom is attracted a significant distance, 0.5 Å, toward one of the four corners of the tetrahedron. This may be one reason why Ti@C28 is exptl. less abundant and stable than U.C28, which has a larger endohedral atom.
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253Skwara, B.; Góra, R. W.; Zalesny, R.; Lipkowski, P.; Bartkowiak, W.; Reis, H.; Papadopoulos, M. G.; Luis, J. M.; Kirtman, B. Electronic structure, bonding, spectra, and linear and nonlinear electric properties of Ti@C28. J. Phys. Chem. A 2011, 115, 10370– 10381, DOI: 10.1021/jp206331n253https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtV2ntL3K&md5=23eb87d8cf5cf343333aa4ac047ca505Electronic Structure, Bonding, Spectra, and Linear and Nonlinear Electric Properties of Ti@C28Skwara, Bartlomiej; Gora, Robert W.; Zalesny, Robert; Lipkowski, Pawel; Bartkowiak, Wojciech; Reis, Heribert; Papadopoulos, Manthos G.; Luis, Josep M.; Kirtman, BernardJournal of Physical Chemistry A (2011), 115 (37), 10370-10381CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The potential energy surface (PES) of Ti@C28 has been revisited, and the stationary points have been carefully characterized. In particular, the C2v symmetry structure considered previously turns out to be a transition state lying 2.3 kcal/mol above the ground state of C3v symmetry at the MP2/6-31G(d) level. A large binding energy of 181.3 kcal/mol is found at the ROMP2/6-31G(d) level. Topol. anal. of the generalized Ti@C28 d. reveals four bond paths between Ti and carbon atoms of the host. The character of all four contacts corresponds to a partially covalent closed shell interaction. UV-vis, IR, and Raman spectra are calcd. and compared with C28H4. The dipole moment and the static electronic and double harmonic vibrational (hyper)polarizabilities have been obtained. Distortion of the fullerene cage due to encapsulation leads to nonzero diagonal components of the electronic first hyperpolarizability β, and to an increase in the diagonal components of the electronic polarizability α and second hyperpolarizability γ. However, introduction of the Ti atom causes a comparable or larger redn. in most cases due to localized bonding interactions. At the double harmonic level, the av. vibrational β is much larger than its electronic counterpart, but the opposite is true for α and for the contribution to γ that has been calcd. There is also a very large anharmonic (nuclear relaxation) contribution to β which results from a shallow PES with four min. sepd. by very low barriers. Thus, the vibrational γ (and α) may, likewise, become much larger when anharmonicity is taken into account.
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254Muñoz-Castro, A.; King, R. B. Formation of spherical aromatic endohedral metallic fullerenes. Evaluation of magnetic properties of M@C28 (M = Ti, Zr, and Hf) from DFT calculations. Inorg. Chem. 2017, 56, 15251– 15258, DOI: 10.1021/acs.inorgchem.7b02611254https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVent77J&md5=3294db1f499724674499e6639b6c3e17Formation of Spherical Aromatic Endohedral Metallic Fullerenes. Evaluation of Magnetic Properties of M@C28 (M = Ti, Zr, and Hf) from DFT calculationsMunoz-Castro, Alvaro; King, R. BruceInorganic Chemistry (2017), 56 (24), 15251-15258CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)The small C28 cage has been shown exptl. to encapsulate titanium, zirconium, and hafnium (M), among other elements. Here, we explore computationally its magnetic response properties accounting for both global and local shielding tensors. Our results exhibit a continuous shielding region for M@C28 for an orientation-averaged applied field thereby differing from that obsd. for the hollow C28 structure. Moreover, under a specific orientation of the applied field a long-ranged shielding cone is obtained supporting the spherical arom. behavior expected by the 2(N + 1)2 Hirsch rule for M@C28, standing for its particular abundance. The comparison between the hollow and endohedral C28 fullerenes exhibits a characteristic long-range behavior at the outside region of the structure. The particular shape of the local chem. shift anisotropy tensor at a representative carbon atom exhibits inherent patterns as a consequence of the spherical arom. behavior. This shows the capabilities from NMR expts. to account for the nonarom. → arom. variation. We envisage that the current approach will be beneficial in comparative studies of arom. and electronic structure properties, to gain a deeper understanding of the geometrical and electronic structure situation in other endohedral species beyond that available from the information provided by routine NMR measurements.
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255Garg, I.; Sharma, H.; Kapila, N.; Dharamvir, K.; Jindal, V. K. Transition metal induced magnetism in smaller fullerenes (Cn for n ≤ 36). Nanoscale 2011, 3, 217– 224, DOI: 10.1039/C0NR00475H255https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXitVChtLw%253D&md5=1bb807b2775c7f93003c3e95b35ad4e4Transition metal induced magnetism in smaller fullerenes (Cn for n ≤ 36)Garg, Isha; Sharma, Hitesh; Kapila, Neha; Dharamvir, Keya; Jindal, V. K.Nanoscale (2011), 3 (1), 217-224CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The magnetic properties of 3d transition metals (TM) encapsulated inside smaller fullerenes ranging from C20 to C36 have been investigated using spin polarized d. functional theory. The TM impurities stabilize asym. at an off-center position for n ≥ 28. The total magnetic moment (MM) of TM@Cn complexes are largely contributed by TMs and a small amt. of MM of 0.12-0.50 μB is induced on the cage carbon atoms. The 3d TM atoms interact with C atoms of C20 and C28 cage ferromagnetically (FM) except for Ni@C28 which shows antiferromagnetic (AFM) interaction. The magnetic interactions change from FM to AFM in C32 cage for Ti, V, Cr and Mn. The MM gets quenched in Ni@Cn for n ≥ 32. The total MM of Mn@Cn does not show any change although the nature of magnetic interactions changes from FM to AFM at n = 32. Ti and V are the only TMs which show pos. cohesive energy in all fullerenes considered. The smallest fullerene which can encapsulate all 3d TM are Cn for n ≥ 32, consistent with available exptl. and theor. results.
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256Mulet-Gas, M.; Abella, L.; Dunk, P. W.; Rodríguez-Fortea, A.; Kroto, H. W.; Poblet, J. M. Small endohedral metallofullerenes: Exploration of the structure and growth mechanism in the Ti@C2n (2n = 26–50) family. Chem. Sci. 2015, 6, 675– 686, DOI: 10.1039/C4SC02268H256https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFekt7bN&md5=008e74db07759e8b033680a27c84e7baSmall endohedral metallofullerenes: exploration of the structure and growth mechanism in the Ti@C2n (2n = 26-50) familyMulet-Gas, Marc; Abella, Laura; Dunk, Paul W.; Rodriguez-Fortea, Antonio; Kroto, Harold W.; Poblet, Josep M.Chemical Science (2015), 6 (1), 675-686CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)The formation of the smallest fullerene, C28, was recently reported using gas phase expts. combined with high-resoln. FT-ICR mass spectrometry. An internally located group IV metal stabilizes the highly strained non-IPR C28 cage by charge transfer (IPR = isolated pentagon rule). Ti@C44 also appeared as a prominent peak in the mass spectra, and U@C28 was demonstrated to form by a bottom-up growth mechanism. We report here a computational anal. using std. DFT calcns. and Car-Parrinello MD simulations for the family of the titled compds., aiming to identify the optimal cage for each endohedral fullerene and to unravel key aspects of the intriguing growth mechanisms of fullerenes. We show that all the optimal isomers from C26 to C50 are linked by a simple C2 insertion, with the exception of a few carbon cages that require an addnl. C2 rearrangement. The ingestion of a C2 unit is always an exergonic/exothermic process that can occur through a rather simple mechanism, with the most energetically demanding step corresponding to the closure of the carbon cage. The large formation abundance obsd. in mass spectra for Ti@C28 and Ti@C44 can be explained by the special electronic properties of these cages and their higher relative stabilities with respect to C2 reactivity. We further verify that extrusion of C atoms from an already closed fullerene is much more energetically demanding than forming the fullerene by a bottom-up mechanism. Independent of the formation mechanism, the present investigations strongly support that, among all the possible isomers, the most stable, smaller non-IPR carbon cages are formed, a conclusion that is also valid for medium and large cages.
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257Muñoz-Castro, A.; Bruce King, R. Evaluation of bonding, electron affinity, and optical properties of M@C28 (M = Zr, Hf, Th, and U): Role of d-and f-orbitals in endohedral fullerenes from relativistic DFT calculations. J. Comput. Chem. 2017, 38, 44– 50, DOI: 10.1002/jcc.24518257https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslamtbfE&md5=7a59cf17cabbe136bdf9c6c78db1c705Bonding, electron affinity, and optical properties of M@C28 (M = Zr, Hf, Th, and U): Role of d- and f-orbitals in endohedral fullerenes from relativistic DFT calculationsMunoz-Castro, Alvaro; Bruce King, R.Journal of Computational Chemistry (2017), 38 (1), 44-50CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)The exptl. characterized endohedral metallic fullerenes involving the small C28 cage, has shown to be able to encapsulate zirconium, hafnium, and uranium atoms, among other elements. Here, we explore the formation and nature of concentric bonds from purely d- to f-block elements, given by Zr, Hf, and uranium, along a borderline metal between such blocks, thorium. We explore the interplay of d- and f-orbitals in the chem. of the early actinides, where the features of a d- or f-block metal can be mixed. Our results indicate that the bonding of Th@C28 involves contributions from both d- and f-type bonds, as characteristic of this early actinide element. Even uranium in U@C28, also exhibits a contribution from d-type bonds in addn. to its relevant f-block character. Electron affinity and optical properties were evaluated to gain more insights into the variation of these mol. properties in this small endohedral fullerene, along Zr, Hf, Th, and U. The current results, allows to unravel the role of (n - 1)d and (n - 2)f orbitals in confined elements ranging from d- to f-blocks, which can be useful to gain a deeper understanding of the bonding situation in other endohedral species.
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258Tuan, D. F.-T.; Pitzer, R. M. Electronic Structure of Hf@C28 and Its Ions. 2. CI Calculations. J. Phys. Chem. 1995, 99, 15069– 15073, DOI: 10.1021/j100041a023258https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXotFWnt70%253D&md5=bc69d5c478bc68dd5cefde8dec2291dfElectronic Structure of Hf@C28 and Its Ions. 2. CI CalculationsTuan, Debbie Fu-Tai; Pitzer, Russell M.Journal of Physical Chemistry (1995), 99 (41), 15069-73CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)Ab initio CI calcns. were performed on the ground and excited state of Hf@C28 and its pos. and neg. ions. Relativistic core potentials, spin-orbit operators, and symmetry-adapted functions were included in the calcns. to take into account the relativistic effects of the heavy atom and to reduce the time and effort of the computation. Double-zeta basis sets were used. Single and double excitations were included in the CI calcns. A no. of excitation energies were obtained for the Hf@C28 and its ions. The ground states of Hf@C28+, Hf@C28, and Hf@C28- in Td symmetry were found to be 2A1, 1A1, and 2E. For Hf@C28, values found were the following: ionization potential, 8.08 eV; electron affinity, 0.66 eV; and first excitation energy (to 3E state), 5.26 eV. The binding energy for Hf and C28 to form Hf@C28 was obtained as 0.71 eV. These results were compared with those from our previous SCF calcns. and with exptl. data or other theor. values where available.
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259Zhao, K.; Pitzer, R. M. Electronic structure of C28, Pa@C28, and U@C28. J. Phys. Chem. 1996, 100, 4798– 4802, DOI: 10.1021/jp9525649259https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xhtleisb4%253D&md5=26af4fae8c78a00dd07670d7b44aff2bElectronic Structure of C28, Pa@C28, and U@C28Zhao, Ke; Pitzer, Russell M.Journal of Physical Chemistry (1996), 100 (12), 4798-802CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)Electronic structure calcns., including relativistic core potentials and the spin-orbit interaction, have been carried out on the C28, Pa@C28, and U@C28 species. Excitation energies, spin-orbit splittings, the electron affinity, and the ionization potential are computed for C28. The ground state of C28 is described well by the Hartree-Fock wave functions, but other states are not. The computed electron affinity and ionization potential are similar to those of C60. Strong metal-cage binding is found for Pa@C28 and U@C28, similar to that in U(C8H8)2. The ground electronic states depend on the order of the lowest-energy cage π* and metal 5f orbitals, with (π*)1 and (π*)1(5f)1 found to be the ground electronic configurations for the two complexes. U@C28 is found to be diamagnetic.
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260Dai, X.; Gao, Y.; Jiang, W.; Lei, Y.; Wang, Z. U@C28: The electronic structure induced by the 32-electron principle. Phys. Chem. Chem. Phys. 2015, 17, 23308– 23311, DOI: 10.1039/C5CP04127A260https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlejs7jK&md5=3716cc48c2543128ce8f66213b68f4fcU@C28: the electronic structure induced by the 32-electron principleDai, Xing; Gao, Yang; Jiang, Wanrun; Lei, Yanyu; Wang, ZhigangPhysical Chemistry Chemical Physics (2015), 17 (36), 23308-23311CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)First principles calcns. show that the neutral U@C28 has a (cage)2 ground state with Td symmetry instead of the long believed (5f)1(cage)1 ground state with D2 symmetry. Its 34 valence electrons preferentially obey the 32-electron principle which fills all the s-, p-, d-, and f-type valence shells of the uranium atom. The remaining two valence electrons cannot break the electronic configuration and thus are located on the cage.
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261Rösch, N.; Häberlen, O. D.; Dunlap, B. I. Bonding in endohedral metal–fullerene complexes: F-orbital covalency in Ce@C28. Angew. Chem., Int. Ed. Engl. 1993, 32, 108– 110, DOI: 10.1002/anie.199301081There is no corresponding record for this reference.
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262Dognon, J.-P.; Clavaguéra, C.; Pyykkö, P. A predicted organometallic series following a 32-electron principle: An@C28 (An = Th, Pa+, U2+, Pu4+). J. Am. Chem. Soc. 2009, 131, 238– 243, DOI: 10.1021/ja806811p262https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsVKlu73J&md5=572bde0b4e4d014ccbd3b12dbd825195A Predicted Organometallic Series Following a 32-Electron Principle: An@C28 (An = Th, Pa+, U2+, Pu4+)Dognon, Jean-Pierre; Clavaguera, Carine; Pyykko, PekkaJournal of the American Chemical Society (2009), 131 (1), 238-243CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The spectroscopic and thermodn. properties of the mols. M@C28 (M = Ce, Th, Pa+, U2+, Pu4+) are calcd. using d. functional theory. The systems have considerable energetic stability. It is shown that the actinide cases can be classified as "32-electron" systems, using the bonding s-, p-, d-, and f-type orbitals of the central metal. The rest of the valence MOs have purely carbon character.
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263Ryzhkov, M. V.; Ivanovskii, A. L.; Delley, B. Electronic structure of endohedral fullerenes An@C28 (An = Th–Md). Comput. Theor. Chem. 2012, 985, 46– 52, DOI: 10.1016/j.comptc.2012.01.037263https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjs1OlsLY%253D&md5=c889bb03c85a5696fc1225992e778d70Electronic structure of endohedral fullerenes An@C28 (An = Th - Md)Ryzhkov, Mikhail V.; Ivanovskii, Alexander L.; Delley, BernardComputational & Theoretical Chemistry (2012), 985 (), 46-52CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The geometry optimization of the neutral mols. An@C28 (An = Th - Md) was carried out using the DFT based Dmol3 method. For the calcns. of electronic structure of these complexes we used the fully relativistic discrete variational method (RDV). The systems contg. Th, Pa, U, Np and Pu have considerable energetic stability. It was found, that the 5f-orbitals contribution to chem. bonding is close to that of the 6d-states for the first half of An@C28 row. The effective charges on the atoms were calcd. using integral scheme incorporated in RDV and Hirshfeld procedure of DMol3.
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264Manna, D.; Ghanty, T. K. Prediction of a new series of thermodynamically stable actinide encapsulated fullerene systems fulfilling the 32-electron principle. J. Phys. Chem. C 2012, 116, 25630– 25641, DOI: 10.1021/jp308820z264https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1Wlt7vL&md5=e947187772237178bd300369a1cfae1bPrediction of a New Series of Thermodynamically Stable Actinide Encapsulated Fullerene Systems Fulfilling the 32-Electron PrincipleManna, Debashree; Ghanty, Tapan K.Journal of Physical Chemistry C (2012), 116 (48), 25630-25641CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)D. functional theory (DFT) within the framework of zeroth order regular approxn. has been used to predict a new class of stable clusters through encapsulation of an actinide or lanthanide atom/ion into the C26 cage. The electronic structures, bonding, stability, aromaticity and spectroscopic properties of these endohedral metallofullerenes, M@C26 (M = Pr-, Pa-, Nd, U, Pm+, Np+, Sm2+, Pu2+, Eu3+, Am3+, Gd4+, and Cm4+) have been investigated systematically using DFT and its time-dependent variant. On encapsulation of an f-block metal atom/ion with 6 valence electrons, the classical bare open shell C26 cage with D3h symmetry and ellipsoid shape is transformed to a more spherical closed shell D3h structures with high HOMO-LUMO gap (in the range of 2.44-3.99 eV for M@C26 clusters as compared to 1.62 eV for the bare C26 cage). Calcd. binding energy values imply that all of the M@C26 clusters are stable with respect to dissocn. into at. fragments. Moreover, thermodn. parameters indicate that the encapsulation process is highly favorable for all of the actinides and some of the lanthanides considered here. A higher stability and nearly spherical shape of M@C26 system is rationalized through the fulfillment of 32-electron principle corresponding to the fully occupied spdf at. shells for the encapsulated central atom, where considerable amt. of overlap between the metal and cage orbitals has been found. Thus, the calcd. structural and energetic parameters strongly suggest the possible formation of M@C26 species under appropriate exptl. conditions. Furthermore, the present work implies that the 32-electron principle might be important in designing of new materials involving lanthanides and actinides.
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265Manna, D.; Sirohiwal, A.; Ghanty, T. K. Pu@C24: A new example satisfying the 32-electron principle. J. Phys. Chem. C 2014, 118, 7211– 7221, DOI: 10.1021/jp500453v265https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjvFSjurk%253D&md5=2e1421f110f830f72f38db9483a5cb8dPu@C24: A New Example Satisfying the 32-Electron PrincipleManna, Debashree; Sirohiwal, Abhishek; Ghanty, Tapan K.Journal of Physical Chemistry C (2014), 118 (13), 7211-7221CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A transition in point group symmetry from C2 to D6d in the classical cage isomer of C24 cluster is obsd. after encapsulation of a plutonium atom within it. This encapsulation leads to highly stable Pu@C24 cluster, which is well supported by the structural, energetic, and thermodn. aspects. This study has been carried out with first five low-lying isomers of C24 fullerene, among which one is classical fullerene consisting of only five- and six-membered rings (MR) and remaining four isomers are nonclassical fullerene consisting of five and six MR along with varying no. of four MR. The structural and stability aspects are investigated extensively for the Pu@C24 cluster. For the purpose of comparison we have also considered some other lanthanides/actinides with 8 valence electrons (Cm2+, Sm, and Gd2+) and investigated the encapsulation process into different C24 isomers. The Pu@C24 cluster is the most stable one among all the metallofullerenes considered here. For Pu@C24, it has been obsd. that HOMO-LUMO gap is changed from 1.83 to 3.26 eV after encapsulation of a Pu atom into the bare classical C24 cage. The bare C24 nonclassical (C2 symmetry) cluster is the most stable one; however, after encapsulation, the classical isomer becomes the most stable with significant energy differences. The detail vibrational and electronic spectral studies have also been carried out for the classical Pu@C24 metallofullerene. High HOMO-LUMO gaps and pos. binding energy values for the Pu@C24 clusters and negatives values of reaction enthalpy and free energy corresponding to the encapsulation process indicate toward possible formation of Pu@C24 and subsequent exptl. detection. High stability of the Pu@C24 cluster can be rationalized through the fulfilment of 32 valence electron count corresponding to the fully occupied spdf shells for the central metal atom.
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266Peng, S.; Zhang, Y.; Li, X. J.; Ren, Y.; Zhang, D. X. DFT calculations on the structural stability and infrared spectroscopy of endohedral metallofullerenes. Spectrochim. Acta, Part A 2009, 74, 553– 557, DOI: 10.1016/j.saa.2009.06.051266https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtV2ktb3N&md5=c1ccb62c273e3ff628d54ad954227fabDFT calculations on the structural stability and infrared spectroscopy of endohedral metallofullerenesPeng, Sheng; Zhang, Yan; Li, Xiao Jun; Ren, Yan; Zhang, Deng XinSpectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy (2009), 74A (2), 553-557CODEN: SAMCAS; ISSN:1386-1425. (Elsevier B.V.)Endohedral metallofullerenes M@C24 (M = Li0/+, Na0/+, K0/+, Be0/2+, Mg0/2+ and Ca0/2+) with different spin configurations have been systematically investigated using the hybrid DFT-B3PW91 functional in conjunction with 6-31G(d) basis sets. Our theor. studies show that Li@C24, Be@C24, Be2+C@24, and Mg2+C@24 are energetically favorable. In these endohedral metallofullerenes, only the encapsulated Be and Ca atoms can donate the electrons to the cage. With exception of Be2+C@24, the energy gaps of other charged compds. are larger than that of corresponding neutral compds. We also find that some endohedral metallofullerenes have high energy gaps, but they are unlikely to show high thermodn. stability. Addnl., the vibrational frequencies and active IR intensities are also used as evidence to identify these endohedral metallofullerenes.
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267Sun, Z.; Li, X.; Tian, M.; Zhao, G.; Li, J.; Ma, B. Comparative study on metal-encapsulated TM@C24 and TM@C24H12 (TM = Ti, Zr and Hf). J. Mol. Struct.: THEOCHEM 2009, 913, 265– 269, DOI: 10.1016/j.theochem.2009.08.005267https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFOqtbbI&md5=6b00bffd0f9351c37e1f98a7cd744595Comparative study on metal-encapsulated TM@24 and TM@24H12 (TM=Ti, Zr and Hf)Sun, Zhicheng; Li, Xiaojun; Tian, Maosheng; Zhao, Guangjian; Li, Jincai; Ma, BingJournal of Molecular Structure: THEOCHEM (2009), 913 (1-3), 265-269CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)A comparative anal. of electronic structure and stability of endohedral metallofullerenes TM@24 and TM@24H12 (TM = Ti, Zr and Hf) is systematically performed with the aid of quantum chem. DFT-B3PW91 approach. Our calcd. results show that TM@24H12 display higher symmetry compared with TM@24, and all of endohedral metallofullerenes are in a singlet spin state. Thermodn. data reflect that endohedral metallofullerenes TM@24 are more stable than TM@24H12 and the Ti atom is energetically favorable to be encapsulated. However, these TM@24H12 have higher kinetic stability. The analyses of the vertical electron affinities (VEAs) and vertical ionization potentials (VIPs) indicate the possibilities of accepting electrons of TM@24H12 become weaker and the possibilities of denoting electrons become stronger. Addnl., natural population anal. presents that the natural charge on TM atoms dramatically increases along with increasing at. no., and the 5d orbitals of Zr atom and 6d orbitals of Hf atom are significantly involved in their chem. bonding.
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268Zhang, Y.; Peng, S.; Li, X. J.; Zhang, D. X. Structural stability, electronegativity and electronic property of endohedral TM@C24 and exohedral TMC24 (TM = Sc, Y and La) metallofullerene complexes: Density-functional theory investigations. J. Mol. Struct.: THEOCHEM 2010, 947, 16– 21, DOI: 10.1016/j.theochem.2010.01.030268https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjtFKlsbs%253D&md5=0e31335dbb1ca1b141753ac13d0337eeStructural stability, electronegativity and electronic property of endohedral TM@C24 and exohedral TMC24 (TM=Sc, Y and La) metallofullerene complexes: Density-functional theory investigationsZhang, Yan; Peng, Sheng; Li, Xiao Jun; Zhang, Deng XinJournal of Molecular Structure: THEOCHEM (2010), 947 (1-3), 16-21CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)The structural stability, electronegativity and electronic property of endohedral TM@C24 and exohedral TM-C24 (TM = Sc, Y and La) complexes have been systematically investigated using the hybrid DFT-(U)B3PW91 functional. The calcd. results show that the endohedral complexes do not undergo any major deformation in the structures, and the Sc atom is energetically favorable to be encapsulated into the center of the cage. But in the Y and La cases the exohedral structure is more stable than the endohedral structure. The frontier orbital analyses indicate that the exohedral TM-C24 complexes have the high kinetic stabilities, which are consistent with their thermodn. stabilities. Addnl., natural population analyses also tell us that the natural charges on TM atoms are obviously increased with the increasing at. radii except for the endohedral La@C24. In the La@C24, the La atom acts as an electron acceptor with the neg. charges. And its 4f orbitals are significantly involved in the formation of the chem. bonding.
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269Wu, J.; Sun, Z.; Li, X.; Chen, L.; Tian, M. Molecular geometries, electronic properties, and vibrational spectroscopic studies of endohedral metallofullerenes TM@C24 and TM@C24H12 (TM = Cr, Mo, and W). Struct. Chem. 2010, 21, 673– 680, DOI: 10.1007/s11224-010-9597-7269https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXosVWmtbg%253D&md5=f9158586176e4c1dcaa93af00f26494eMolecular geometries, electronic properties, and vibrational spectroscopic studies of endohedral metallofullerenes TM@C24 and TM@C24H12 (TM = Cr, Mo, and W)Wu, Julong; Sun, Zhicheng; Li, Xiaojun; Chen, Liang; Tian, MaoshengStructural Chemistry (2010), 21 (4), 673-680CODEN: STCHES; ISSN:1040-0400. (Springer)Mol. geometries, electronic properties, and vibrational spectroscopies of TM@CV24 and TM@C 24H12 (TM = Cr, Mo, and W) in their different spin configurations have been systematically investigated with the hybrid DFT-(U)B3PW91 functional. The results show that the TM atoms bind over the pentagon ring inside C24 cage, and they move gradually toward the center of C24 cage along with the increasing at. radii. The most stable Mo@C24H12 and W@C24H12 are in their spin-triplet states. The analyses of dissocn. energy and energy gap reveal that TM@C24 (TM = Cr, Mo, and W) and Cr@C24H12 are not only thermodynamically stable, but also considerably stable kinetically. Meanwhile, natural population analyses tell us that the two cages act as electron acceptors, and the transferred charge from the W atom to C24 cage is the largest in the endohedral metallofullerenes. Addnl., the vibrational frequencies and active IR intensities may be used as evidence to characterize these unknown species.
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270Yue, Y.; Li, X. J. Density functional investigations of endohedral metallofullerenes TM@C24 (TM = Mn, Fe, Co, Ni, Cu, and Zn. Int. J. Quantum Chem. 2011, 111, 96– 102, DOI: 10.1002/qua.22393270https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlaqt7%252FP&md5=2a8aa30e38f91a1e788adcb3e39ce90bDensity functional investigations of endohedral metallofullerenes TM@C24 (TM = Mn, Fe, Co, Ni, Cu, and Zn)Yue, Yun; Li, Xiao-JunInternational Journal of Quantum Chemistry (2011), 111 (1), 96-102CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)The theor. investigations on TM@C24 (TM = Mn, Fe, Co, Ni, Cu, and Zn) with different spin configurations have been performed by using the hybrid DFT-B3PW91 functional in conjunction with 6-31G(d) basis sets. The results show that the ground states of Fe@C24 and Ni@C24 are their spin triplet states, whereas the ground state of Co@C24 is spin quartet state. Moreover, three Fe@C24 isomers are favorable in energy. The HOMO and LUMO of Zn@C24 indicates that there is no hybridization between Zn AOs and the C24 cage orbitals. Natural population anal. shows that the charges always transfer from the TM atoms to the C24 cage. In going from isolated TM atom to TM@C24, the occupation of the 4s orbital is strongly reduced. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011.
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271Erkoç, Ş. Metal atom endohedrally doped C20 cage structure: (X@C20; X = Ni, Fe, Co. Int. J. Mod. Phys. C 2005, 16, 1553– 1560, DOI: 10.1142/S0129183105008138271https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFOrsb3I&md5=41ee6e9fd56c10ac28f02ad7212c50f8Metal atom endohedrally doped C20 cage structure: (X@C20; X = Ni, Fe, Co)Erkoc, SakirInternational Journal of Modern Physics C (2005), 16 (10), 1553-1560CODEN: IJMPCM; ISSN:0129-1831. (World Scientific Publishing Co. Pte. Ltd.)The C20 cage structure (X@C20; X = Fe, Co, Ni) endohedrally doped with a metal atom has been investigated theor. by performing mol.-mechanics optimizations, and semi-empirical PM3 level and d. functional theory B3LYP/6-31G* level calcns. within UHF formalism. Calcns. have been performed with different spin configurations for the neutral systems.
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272Poklonski, N. A.; Kislyakov, E. F.; Vyrko, S. A.; Hieu, N. N.; Bubel, O. N.; Siahlo, A. I.; Lebedeva, I. V.; Knizhnik, A. A.; Popov, A. M.; Lozovik, Y. E. Magnetically operated nanorelay based on two single-walled carbon nanotubes filled with endofullerenes Fe@C20. J. Nanophotonics 2010, 4, 041675, DOI: 10.1117/1.3417104There is no corresponding record for this reference.
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273Samah, M.; Boughiden, B. Structures, electronic and magnetic properties of C20 fullerenes doped transition metal atoms M@C20 (M = Fe, Co, Ti, V). Int. J. Mod. Phys. C 2010, 21, 1469– 1477, DOI: 10.1142/S0129183110015968273https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhs1SrtbjP&md5=19d69cfd5de68ee9f0e62ecc6c3d028cStructures, electronic and magnetic properties of C20 fullerenes doped transition metal atoms M@20 (M = Fe, Co, Ti, V)Samah, M.; Boughiden, B.International Journal of Modern Physics C: Computational Physics, Physical Computation (2010), 21 (12), 1469-1477CODEN: IJMPCM; ISSN:0129-1831. (World Scientific Publishing Co. Pte. Ltd.)Structures, binding energies, magnetic and electronic properties endohedrally doped C20 fullerenes by metallic atoms (Fe, Co, Ti and V) have been obtained by pseudopotential d. functional theory. All M@20, except Co@20, are more stable than the undoped C20 cage. The magnetic moment values are 1 and 2μB. These values and semiconductor behavior give to these compds. interesting feature in several technol. applications. Titanium doped C20 has a same magnetic moment than the isolated Ti atom. Hybridization process in the Co doped C20 fullerene is most strong than in other doped cages. Elec. and magnetic dipoles calcd. in the iron doped C20 are very strong compared with other clusters.
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274Baei, M. T.; Soltani, A.; Torabi, P.; Hosseini, F. Formation and electronic structure of C20 fullerene transition metal clusters. Monatsh. Chem. 2014, 145, 1401– 1405, DOI: 10.1007/s00706-014-1218-5274https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXovVWrtLc%253D&md5=eebd3b176194b37d8efd2a95890191cbFormation and electronic structure of C20 fullerene transition metal clustersBaei, Mohammad T.; Soltani, Alireza; Torabi, Parviz; Hosseini, FarzanehMonatshefte fuer Chemie (2014), 145 (9), 1401-1405CODEN: MOCMB7; ISSN:0026-9247. (Springer-Verlag GmbH)The structure and electronic properties of TM@C20 (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) complexes were investigated. The study revealed that the doping processes of Sc, Ti, V, Cr, Mn, and Fe atoms at the center of C20 fullerene are exothermic and those of Co, Ni, Cu, and Zn atoms are endothermic. In addn., the endohedral complexation with Sc, Ti, V, Cr, Mn, and Fe atoms significantly influence the electronic properties of the C20 clusters. The calcd. vibrational frequencies for the Ti, V, and Mn complexes were pos., confirming the complexes are stable and can stabilize the unstable C20 fullerene with Ih symmetry. The present results reveal details for the synthesis and structuring of C20 fullerene doped with Ti, V, and Mn and serves for the further developments of C20-based particles to generate new hybrid compds.
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275An, Y.-P.; Yang, C.-L.; Wang, M.-S.; Ma, X.-G.; Wang, D.-H. Ab initio investigations of the charge transport properties of endohedral M@C20 (M = Na and K) metallofullerenes. Chin. Phys. B 2010, 19, 113402, DOI: 10.1088/1674-1056/19/11/113402275https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisVCgt74%253D&md5=c26f5095f8a72302976df87f0990fa77Ab initio investigations of the charge transport properties of endohedral M@C20 (M = Na and K) metallofullerenesAn, Yi-Peng; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Wang, De-HuaChinese Physics B (2010), 19 (11), 113402/1-113402/6CODEN: CPBHAJ; ISSN:1674-1056. (Chinese Physical Society)Using d. functional theory and quantum transport calcns. based on nonequilibrium Green's function formalism, we investigate the charge transport properties of endohedral M@C20(M = Na and K) metallofullerenes. Our results show that the conductance of C20 fullerene can be obviously improved by insertion of alkali atom at its center. Both linear and nonlinear sections are found on the I-V curves of the Au-M@C20-Au two-probe systems. The novel neg. differential resistance behavior is also obsd. in Na@C20 mol. but not in K@C20.
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276An, Y.-P.; Yang, C.-L.; Wang, M.-S.; Ma, X.-G.; Wang, D.-H. Geometrical and electronic properties of the clusters of C20 cage doped with alkali metal atoms. J. Cluster Sci. 2011, 22, 31– 39, DOI: 10.1007/s10876-011-0354-x276https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjtFamtrs%253D&md5=b941e4f1b23f54622026633334eae753Geometrical and Electronic Properties of the Clusters of C20 Cage Doped with Alkali Metal AtomsAn, Yi-Peng; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Wang, De-HuaJournal of Cluster Science (2011), 22 (1), 31-39CODEN: JCSCEB; ISSN:1040-7278. (Springer)Using first-principles d.-functional theory based on the generalized gradient approxn., we have investigated the geometrical and electronic properties of the pure C20 cage with D3d symmetry and M@20(M = Li, Na, K, Rb, Cs) clusters with Ih symmetry. It is found that the interstitial M@20 clusters are energetically stable and have strong total magnetic moments. The stability is analyzed through charge distributions on the atoms and the magnetism is explained through the degeneracy and fractional occupation of the MOs.
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277Wu, J.; Sun, Z.; Li, X.; Ma, B.; Tian, M.; Li, S. Theoretical study on the smallest endohedral metallofullerenes: TM@C20 (TM = Ce and Gd). Int. J. Quantum Chem. 2010, 111, 3786– 3792, DOI: 10.1002/qua.22908There is no corresponding record for this reference.
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278Manna, D.; Ghanty, T. K. Theoretical prediction of icosahedral U@C20 and analogous systems with high HOMO–LUMO gap. J. Phys. Chem. C 2012, 116, 16716– 16725, DOI: 10.1021/jp302138p278https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XptF2nsLs%253D&md5=656141002733654e9a1f06aa0c6dd9ddTheoretical Prediction of Icosahedral U@C20 and Analogous Systems with High HOMO-LUMO GapManna, Debashree; Ghanty, Tapan K.Journal of Physical Chemistry C (2012), 116 (31), 16716-16725CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The electronic structures, bonding, stability, aromaticity, and spectroscopic properties of the endohedral metallofullerenes, M@C20 (M = Pr-, Pa-, Nd, U, Pm+, Np+, Sm2+, Pu2+, Eu3+, Am3+, Gd4+, and Cm4+), were investigated in a unified and systematic way using relativistic d. functional theory (DFT) within the framework of zeroth-order regular approxn. The bare C20 cage with D3d point group transforms to highly sym. Ih structure through encapsulation of an f-block metal atom/ion with 6 valence electrons. The calcd. values of HOMO-LUMO gap lie in the range of 2.5-4.9 eV (8.8-11.5 eV) at the B3LYP (HF) level. The stability of these metal encapsulated clusters can be attributed to the fulfillment of 26 valence electrons criteria corresponding to the fully occupied 2s2p1d at. shells, where strong participation of the central metal atom orbitals in the ag, t1u, gu, and hg valence MOs have been obsd.
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279Meng, F.; Zhou, Z.; Zhang, P.; Jiang, M.; Xu, X.; Wang, Y.; Gou, J.; Hui, D.; Die, D. Encapsulation of an f-block metal atom/ion to enhance the stability of C20 with the Ih symmetry. Phys. Chem. Chem. Phys. 2015, 17, 4328– 4336, DOI: 10.1039/C4CP03159H279https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvVWqug%253D%253D&md5=9c1fdc2da4a59129e2661b81d118f86aEncapsulation of an f-block metal atom/ion to enhance the stability of C20 with the Ih symmetryMeng, Fanchen; Zhou, Zuowan; Zhang, Pinliang; Jiang, Man; Xu, Xiaoling; Wang, Yong; Gou, Jihua; Hui, David; Die, DongPhysical Chemistry Chemical Physics (2015), 17 (6), 4328-4336CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Based on the d. functional theory, the geometric and electronic structures, chem. stability, and bonding properties of the endohedral metallofullerenes, M@C20 (M = Eu3-, Am3-, Gd2-, Cm2-, Tb-, Bk-, Dy, Cf, Ho+, Es+, Er2+, Fm2+, Tm3+, Md3+, Yb4+, No4+, Lu5+, and Lr5+), were investigated. Through encapsulation of an f-block metal atom/ion with 12 valence electrons, the bare C20 cage with the D2h point group could be stabilized to a highly sym. Ih structure. The calcd. values of HOMO-LUMO energy gaps using the B3lYP and BHHLYP functionals ranged from 2.22 to 5.39 eV and from 3.89 to 7.95 eV, resp. The stability of these metal-encapsulated clusters can be attributed to the 32-electron rule, where the central metal atom's orbitals strongly participated in the t2u, gu, t1u, hg, and ag valence MOs.
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280Muñoz-Castro, A.; King, R. B. On the formation of smaller p-block endohedral fullerenes: Bonding analysis in the E@C20 (E = Si, Ge, Sn, Pb) series from relativistic DFT calculations. J. Comput. Chem. 2017, 38, 1661– 1667, DOI: 10.1002/jcc.24809280https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXmsFantrY%253D&md5=067a7461acf5147cc3607513f6f3ca88On the formation of smaller p-block endohedral fullerenes: Bonding analysis in the E@C20 (E = Si, Ge, Sn, Pb) series from relativistic DFT calculationsMunoz-Castro, Alvaro; King, R. BruceJournal of Computational Chemistry (2017), 38 (19), 1661-1667CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)Exptl. characterized endohedral metallofullerenes are of current interest in expanding the range of viable fullerenic structures and their applications. Smaller metallofullerenes, such as M@C28, show that several d- and f-block elements can be efficiently confined in relatively small carbon cages. This article explores the potential capabilities of the smallest fullerene cage, i.e., C20, to encapsulate p-block elements from group 14, i.e., E = Si, Ge, Sn, and Pb. Our interest relates to the bonding features and optical properties related to E@C20. The results indicate both s- and p-type concentric bonds, in contrast to the well explored endohedral structures encapsulating f-block elements. Our results suggest the E@C20 series to be a new family of viable endohedral fullerenes. In addn., optical and vibrational spectroscopic properties and electron affinity were modeled to gain further information useful for characterization. Characteristic optical patterns were studied predicting a distinctive first peak located between 400 and 250 nm, which is red-shifted going to the heavier encapsulated Group 14 atoms. Electron affinity properties expose different patterns useful to differentiate the hollow C20 fullerene to the proposed p-block endohedral counterparts. © 2017 Wiley Periodicals, Inc.
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281Gonzalez, M.; Lujan, S.; Beran, K. A. Investigation into the molecular structure, electronic properties, and energetic stability of endohedral (TM@C20) and exohedral (TM-C20) metallofullerene derivatives of C20: TM = Group 11 and 12 transition metal atoms/ions. Comput. Theor. Chem. 2017, 1119, 32– 44, DOI: 10.1016/j.comptc.2017.09.013281https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFOltbbK&md5=11c23b5ffeb42a99040017b813a9fa5eInvestigation into the molecular structure, electronic properties, and energetic stability of endohedral (TM@C20) and exohedral (TM-C20) metallofullerene derivatives of C20: TM = Group 11 and 12 transition metal atoms/ionsGonzalez, Mariela; Lujan, Samantha; Beran, Kyle A.Computational & Theoretical Chemistry (2017), 1119 (), 32-44CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)D.-functional theory at the B3LYP/LanL2DZ level has been employed to probe the structure and electronic properties of the D2h-sym. C20 fullerene. The energetic stability of C20 is assessed as transition metals (TM) from Groups 11 and 12 are inserted at either endohedral (TM@C20) or exohedral (TM-C20) sites. The anal. encompasses various ionizations and spin states for each metal. The lowest-energy exohedral derivs. in Group 11 all favor the low spin-state, whereas the neutral Group 12 complexes favor the high spin-state. The energetic stability of the exohedral, as measured by the dissocn. energy, increases as the charge increases for a given metal. Significantly more interaction occurs between the TM and the C20 cage in the endohedral derivs. as is evidenced by elec. charge being transferred to the carbon cage from both the ns and (n-1)d AOs of the TM. There was not an obsd. preference of spin-state for the endohedrals since in many cases the relative energy difference between comparable spin-states ranged between 0.00 eV and 1.10 eV. Of the endohedrals only Zn@C2+20 and Cu@C2+20 yielded total energies that were less and therefore more stable than the isolated C20 and TM entities.
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282Szwacki, N. G.; Sadrzadeh, A.; Yakobson, B. I. B80 fullerene: An ab initio prediction of geometry, stability, and electronic structure. Phys. Rev. Lett. 2007, 98, 166804, DOI: 10.1103/PhysRevLett.98.166804There is no corresponding record for this reference.
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283Szwacki, N. G.; Sadrzadeh, A.; Yakobson, B. I. Erratum: B80 Fullerene: An ab initio prediction of geometry, stability, and electronic structure [Phys. Rev. Lett. 98, 166804 (2007)]. Phys. Rev. Lett. 2008, 100, 159901, DOI: 10.1103/PhysRevLett.100.159901There is no corresponding record for this reference.
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284Zhao, J.; Wang, L.; Li, F.; Chen, Z. B80 and other medium-sized boron clusters: Core–shell structures, not hollow cages. J. Phys. Chem. A 2010, 114, 9969– 9972, DOI: 10.1021/jp1018873284https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXpvFSntbo%253D&md5=92ced38cd00f048b6b723b692db50963B80 and Other Medium-Sized Boron Clusters: Core-Shell Structures, Not Hollow CagesZhao, Jijun; Wang, Lu; Li, Fengyu; Chen, ZhongfangJournal of Physical Chemistry A (2010), 114 (37), 9969-9972CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Unbiased search on the potential energy surface of medium-sized boron clusters, with B80, B74, and B68 as representatives, was carried out using simulated annealing incorporated with first-principles DFT-GGA-PBE mol. dynamics. These boron clusters thermodynamically prefer the B12-centered core-shell structures, which resemble the fragment of bulk boron solids. Though these core-shell clusters lack a descriptive symmetry and may not be the true global min.; the core-shell B80 is about 25 meV/atom lower in energy than the widely assumed highly stable "magic" B80 fullerene. The electronic states and photoelectron spectra of these clusters are closely correlated to the structural motif, which may be helpful for detecting the cluster configurations in expts.
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285De, S.; Willand, A.; Amsler, M.; Pochet, P.; Genovese, L.; Goedecker, S. Energy landscape of fullerene materials: A comparison of boron to boron nitride and carbon. Phys. Rev. Lett. 2011, 106, 225502, DOI: 10.1103/PhysRevLett.106.225502285https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXotVCgs70%253D&md5=5ac23fb09e9225c5a4bc9b8b784a292cEnergy Landscape of Fullerene Materials: A Comparison of Boron to Boron Nitride and CarbonDe, Sandip; Willand, Alexander; Amsler, Maximilian; Pochet, Pascal; Genovese, Luigi; Goedecker, StefanPhysical Review Letters (2011), 106 (22), 225502/1-225502/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Using the min. hopping global geometry optimization method on the d. functional potential energy surface we show that the energy landscape of boron clusters is glasslike. Larger boron clusters have many structures which are lower in energy than the cages. This is in contrast to carbon and boron nitride systems which can be clearly identified as structure seekers. The differences in the potential energy landscape explain why carbon and boron nitride systems are found in nature whereas pure boron fullerenes have not been found. We thus present a methodol. which can make predictions on the feasibility of the synthesis of new nanostructures.
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286Rahane, A. B.; Kumar, V. B84: A quasi-planar boron cluster stabilized with hexagonal holes. Nanoscale 2015, 7, 4055– 4062, DOI: 10.1039/C4NR06026A286https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVGjtbs%253D&md5=1f277aebc5053b4f48cfd32f8ae78170B84: a quasi-planar boron cluster stabilized with hexagonal holesRahane, Amol B.; Kumar, VijayNanoscale (2015), 7 (9), 4055-4062CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)We report the finding of a bowl-shaped quasi-planar structure of a B84 cluster with four hexagonal holes and a three-chain ring all around the edges using ab initio calcns. A large no. of other isomers including those explored earlier such as an empty cage, a filled cage, and a disordered structure, have been found to lie in a significantly higher energy band. A tubular structure, however, is only about 0.45 eV higher in energy. Calcns. of the IR and Raman spectra show that the quasi-planar structure is dynamically stable. These results suggest that quasi-planar structures may be among the low energy structures for larger clusters as well. Accordingly we have calcd. the optimal quasi-planar structures stabilized with 2, 3, 5, 6, and 7 hexagonal holes also. The stability of quasi-planar structures is discussed in terms of multi-center two-electron bonding and it is shown that with increasing size their binding energy tends to approach the value for an α-boron sheet.
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287Xu, S.-G.; Zhao, Y.-J.; Yang, X.-B.; Xu, H. A practical criterion for screening stable boron nanostructures. J. Phys. Chem. C 2017, 121, 11950– 11955, DOI: 10.1021/acs.jpcc.7b03359287https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXnvFCmt7k%253D&md5=6b550d34d8f600a23bfa8898b166a5ddA Practical Criterion for Screening Stable Boron NanostructuresXu, Shao-Gang; Zhao, Yu-Jun; Yang, Xiao-Bao; Xu, HuJournal of Physical Chemistry C (2017), 121 (21), 11950-11955CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Due to the electron deficiency, boron clusters evolve strikingly with the increasing size as confirmed by experimentalists and theorists. However, it is still a challenge to propose a model potential to describe the stabilities of boron. On the basis of the 2c-2e and 3c-2e bond models, we have found the constraints for stable boron clusters, which can be used for detg. the vacancy concn. and screening the candidates. Among numerous tubular structures and quasi-planar structures, we have verified that the stable clusters with lower formation energies bounded by the constraints, indicating the competition of tubular and planar structures. Notably, we have found a tubular cluster of B76 which is more stable than the B80 cage. We show that the vacancies, as well as the edge, are necessary for the 2c-2e bonds, which will stabilize the boron nanostructures. Therefore, the quasi-planar and tubular boron nanostructures could be as stable as the cages, which have no edge atoms. Our finding has shed light on understanding the complicated electron distributions of boron clusters and enhancing the efficiency of searching stable B nanostructures.
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288Pochet, P.; Genovese, L.; De, S.; Goedecker, S.; Caliste, D.; Ghasemi, S. A.; Bao, K.; Deutsch, T. Low-energy boron fullerenes: Role of disorder and potential synthesis pathways. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 83, 081403, DOI: 10.1103/PhysRevB.83.081403288https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXis1Oqsr4%253D&md5=daaa38cac0aec85cc9809d95797a4256Low-energy boron fullerenes: Role of disorder and potential synthesis pathwaysPochet, Pascal; Genovese, Luigi; De, Sandip; Goedecker, Stefan; Caliste, Damien; Ghasemi, S. Alireza; Bao, Kuo; Deutsch, ThierryPhysical Review B: Condensed Matter and Materials Physics (2011), 83 (8), 081403/1-081403/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We show by means of first-principles BigDFT-code calcns. that in boron nanostructures a large variety of two-dimensional structures can be obtained, all with similar energetic properties. Some of these new structures are more stable than both the B80 fullerenes initially proposed by Szwacki and boron nanotubes. At variance from other systems like carbon, disordered configurations are energetically comparable with ordered ones. Cage-like structures that are not ordered are thus comparable in energy to the more ordered original B80 fullerene. A comparison with other more disordered structures like bulk-like boron clusters is also presented. We found that in the presence of other seed structures (like Sc3 or Sc3N), some endohedral cage-like structures are energetically preferred over bulk-like clusters. This result opens a new pathway for the synthesis of the B80 fullerene as an endohedral fullerene as was done in the case of the C80 fullerene.
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289Li, J. L.; Yang, G. W. Iron endohedral-doped boron fullerene: A potential single molecular device with tunable electronic and magnetic properties. J. Phys. Chem. C 2009, 113, 18292– 18295, DOI: 10.1021/jp9064592289https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFyqsrnI&md5=ca78ad784bd1747cbb3e3fa9994fd859Iron Endohedral-Doped Boron Fullerene: A Potential Single Molecular Device with Tunable Electronic and Magnetic PropertiesLi, J. L.; Yang, G. W.Journal of Physical Chemistry C (2009), 113 (42), 18292-18295CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The authors have theor. performed that Fe endohedral-doped boron fullerene (B80) is a potential single mol. device with tunable electronic and magnetic properties. Both the energy gap and magnetic moment of the Fe endohedral-doped B80 can be greatly tuned, simultaneously by changing the position of the Fe atom inside the hollow cage of B80. In comparison with that of the Fe endohedral-doped B80 with Fe atom located at center-at, the energy gap decreases half and the magnetic moment decreases zero for the case of the Fe endohedral-doped B80 with the Fe atom located at hexagon-in in the hollow cage. These fascinating findings imply that the Fe endohedral-doped B80 with tunable electronic and magnetic properties can be expected to be applicable as a single mol. device.
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290Li, J. L.; Yang, G. W. Tuning electronic and magnetic properties of endohedral Co@B80 and exohedral Co-B80 metallofullerenes by positioning Co atom. J. Appl. Phys. 2010, 107, 113702, DOI: 10.1063/1.3431522290https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvVajtb4%253D&md5=cf9d13e3683aa56c017ef0de32e5732eTuning electronic and magnetic properties of endohedral Co@B80 and exohedral Co-B80 metallofullerenes by positioning Co atomLi, J. L.; Yang, G. W.Journal of Applied Physics (2010), 107 (11), 113702/1-113702/5CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)We have performed a systematical study of the structural configurations, electronic and magnetic properties of the single Co-doped endohedral Co@B80 and exohedral Co-B80 metallofullerene complexes using spin-polarized d. functional calcns. Our calcns. revealed that there are 4 stable configurations of the Co-doped metallofullerenes depending on different positions of the doping Co atoms as follows. In the case of the exohedral Co-B80 metallofullerene complexes, Co atom energetically prefers standing near the centers of pentagon (pentagon-out) and hexagon (hexagon-out) on the surface of B80. In the case of the endohedral Co@B80 metallofullerene complexes, the encapsulated Co atom energetically prefers standing near the centers of pentagon (pentagon-in) and hexagon (hexagon-in) on the inner surface of the hollow cage of B80. Electronically, the energy gaps of the hexagon-near adsorbed metallofullerenes were greatly modified compared with that of B80. At the same time, the magnetic moments of both of the exohedral Co-B80 metallofullerenes are 1/3 of that of the isolated Co atom. The tunable electronic and magnetic properties of the Co-doped B80 metallofullerenes clearly showed that this new type of metallofullerenes may be a promising candidate for mol. devices, esp. single mol. spin electronic devices. (c) 2010 American Institute of Physics.
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291Li, J. L.; Yang, G. W. Ni@B80: A single molecular magnetic switch. Appl. Phys. Lett. 2009, 95, 133115, DOI: 10.1063/1.3242362291https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1Wmt7jN&md5=9aa7d8e72409ea6f3530836f6b0c0c1cNi@B80: A single molecular magnetic switchLi, J. L.; Yang, G. W.Applied Physics Letters (2009), 95 (13), 133115/1-133115/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The authors theor. performed that the magnetic moment of Ni-encapsulated B80(Ni@B80) can be greatly tuned by changing the position of Ni atom inside the hollow cage of B80. There are three stable configurations of Ni@B80 with Ni atom located at center, pentagon, and hexagonal-in, resp. Compared with that of Ni @ B80 with Ni atom located at center, all the magnetic moments of Ni @ B80's with Ni atom located at pentagon and hexagon-in in the hollow cage of B80 are zero. These fascinating findings imply that Ni @ B80 may be a promising candidate for single mol. magnetic switch. (c) 2009 American Institute of Physics.
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292Li, C.; Liu, J.; Lefkidis, G.; Hübner, W. Reversible ultrafast spin switching on Ni@B80 endohedral fullerene. Phys. Chem. Chem. Phys. 2017, 19, 673– 680, DOI: 10.1039/C6CP06492B292https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFCjur%252FF&md5=b9bc0238a74d098b9816ce02c9a9f779Reversible ultrafast spin switching on Ni@B80 endohedral fullereneLi, Chun; Liu, Jing; Lefkidis, Georgios; Hubner, WolfgangPhysical Chemistry Chemical Physics (2017), 19 (1), 673-680CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We present the configurations and stability of the endohedral metallofullerene Ni@B80 by using strict and elaborate geometric modeling. The ultrafast spin switching on Ni@B80 is explored through ab initio calcns. It is shown that there are three stable configurations of Ni@B80 endohedral fullerene with the encaged Ni atom located at different sites. The ultrafast spin switching on Ni@B80via Λ processes can be achieved through at least eight paths with different laser pulses. Among them, the fastest one can be accomplished within 100 fs. In particular, it is found that all the spin-switching processes achieved on the H-type structure are reversible with the use of the same or different laser pulses. Considering the obtained high fidelities of these switching processes, the present theor. prediction could lead to promising applications in the design of integrated spin-logic devices through appropriate spin manipulation in endohedral boron fullerenes.
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293Mahdavifar, Z.; Poulad, M. Theoretical prediction of ozone sensing using pristine and endohedral metalloboron B80 fullerenes. Sens. Actuators, B 2014, 205, 26– 38, DOI: 10.1016/j.snb.2014.08.059293https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVOhsbnJ&md5=19066847ae611e03e7983605341be0e3Theoretical prediction of ozone sensing using pristine and endohedral metalloboron B80 fullerenesMahdavifar, Zabiollah; Poulad, MarziyehSensors and Actuators, B: Chemical (2014), 205 (), 26-38CODEN: SABCEB; ISSN:0925-4005. (Elsevier B.V.)The adsorption of ozone on B80 and endohedral Be@B80 fullerenes is ascertained with d. functional theory. The potential energy curve of ozone adsorption on pristine and endohedral B80 fullerenes is investigated. Obtained data indicate that the behavior of O3 adsorption on investigated fullerenes can be better described by Cor.-Morse potential equation. On the basis of results, the ozone can be adsorbed onto the outer surface of pristine B80 mol. with adsorption energy of -327.34 kJ mol-1. The tangible adsorption energy of O3 onto the B80 and relatively bond length of B-O (∼1.45 Å) in B80/O3 system imply that this structure is of highly stability. Compared the calcd. adsorption energy of O3 adsorbed on Be@B80 system (-498.87 kJ mol-1) with pristine B80, indicate that when the metal atom encapsulated into the B80 fullerene, the adsorption of ozone on Be@B80 is more favorable than pristine B80. Also, the presence of Be metal atom can be improved the oxidn. process of B80 fullerene. During the oxidn. process of Be@B80 fullerene using ozone, the Be metal atom translated from the center to wall of the B80 and strongly bonded to the boron atoms of inner walls. Based on our results, it seems that ozone tends to be chemisorbed onto the B80 and Be@B80 fullerenes with appreciable adsorption energy, whereas the Be@B80 fullerene is more favorable than pristine B80. Furthermore, due to the disappeared some energy level near the LUMO and decreased the Eg, the elec. conductance of the B80/O3 and Be@B80/O3 systems are increased. In conclusion, pristine B80 and Be@B80 fullerenes can be converted the presence of O3 mol. directly to an elec. signal, and therefore, it can be potentially used as ozone sensor.
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294Jin, P.; Hao, C.; Gao, Z.; Zhang, S. B.; Chen, Z. Endohedral metalloborofullerenes La2@B80 and Sc3N@B80: A density functional theory prediction. J. Phys. Chem. A 2009, 113, 11613– 11618, DOI: 10.1021/jp9019848294https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXos1Cgsb4%253D&md5=42c9a4fbf44ed9526b6404474a1e9dd8Endohedral Metalloborofullerenes La2@B80 and Sc3N@B80: A Density Functional Theory PredictionJin, Peng; Hao, Ce; Gao, Zhanxian; Zhang, Shengbai B.; Chen, ZhongfangJournal of Physical Chemistry A (2009), 113 (43), 11613-11618CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The geometries, electronic and spectroscopic properties of two representative endohedral derivs. of B80 fullerene, namely, La2@B80 and Sc3N@B80, and the possibility for their prodn. were investigated by means of d. functional computations. The very favorable binding energies suggest a considerable possibility to exptl. realize these novel endohedral metalloborofullerenes. IR absorption spectra and 11B NMR spectra were also computed to assist future exptl. characterization.
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295Liu, C.; Yang, L.; Jin, P.; Hou, Q.; Li, L. Computational prediction of endohedral dimetalloborofullerenes M2@B80 (M = Sc, Y). Chem. Phys. Lett. 2017, 676, 89– 94, DOI: 10.1016/j.cplett.2017.03.054295https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXltl2ksbY%253D&md5=01a20630de792572efc461d8baacd14cComputational prediction of endohedral dimetalloborofullerenes M2@B80 (M = Sc, Y)Liu, Chang; Yang, Le; Jin, Peng; Hou, Qinghua; Li, LanlanChemical Physics Letters (2017), 676 (), 89-94CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometries and electronic properties of two new endohedral metalloborofullerenes M2@B80 (M = Sc, Y) were investigated by means of d. functional theory computations. The two complexes feature favorable binding energies, suggesting a considerable possibility to be achieved. Sc2@B80 exhibits a flexible metal motion with tunable magnetic moment and may be a promising single mol. magnetic switch. The metal-metal and metal-cage bonding natures were thoroughly disclosed by using various theor. approaches. Their excellent stabilities were confirmed by the Born-Oppenheimer mol. dynamics simulations at different temps. Finally, IR spectra and 11B NMR spectra were simulated to assist exptl. characterization.
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296Jin, P.; Liu, C.; Hou, Q.; Li, L.; Tang, C.; Chen, Z. Scandium carbides/cyanides in the boron cage: Computational prediction of X@B80 (X = Sc2C2, Sc3C2, Sc3CN and Sc3C2CN). Phys. Chem. Chem. Phys. 2016, 18, 21398– 21411, DOI: 10.1039/C6CP02884E296https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVyhsLjE&md5=6c330946e327f2a41285db221bea335dScandium carbides/cyanides in the boron cage: computational prediction of X@B80 (X = Sc2C2, Sc3C2, Sc3CN and Sc3C2CN)Jin, Peng; Liu, Chang; Hou, Qinghua; Li, Lanlan; Tang, Chengchun; Chen, ZhongfangPhysical Chemistry Chemical Physics (2016), 18 (31), 21398-21411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)As the first study on metal carbide/cyanide boron clusterfullerenes, the geometries, energies, stabilities and electronic properties of four novel scandium cluster-contg. B80 buckyball derivs., namely Sc2C2@B80, Sc3C2@B80, Sc3CN@B80 and Sc3C2CN@B80, were investigated by means of d. functional theory computations. The rather favorable binding energies, which are very close to those of the exptl. abundant carbon fullerene analogs, suggest a considerable possibility to realize these doped boron clusterfullerenes. Their intra-cluster and cluster-cage bonding natures were thoroughly revealed by various theor. approaches. In contrast to carbon clusterfullerenes, in which the encaged non-metal atoms mainly play a stabilizing role in the metal clusters, the encapsulated carbon and nitrogen atoms inside the B80 cage covalently bond to the boron framework, resulting in strong cluster-cage interactions. Furthermore, IR spectra and 11B NMR spectra were simulated and fingerprint peaks were proposed to assist future exptl. characterization.
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297Mahdavifar, Z.; Ershadifar, M.; Farrokhnia, A. Electro-optical properties and structural stability perspectives of M3N and M2C2 (M = Sc, La) clusters encapsulated in B80 fullerene: A density functional theory study. J. Electron. Mater. 2018, 47, 550– 565, DOI: 10.1007/s11664-017-5813-1297https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVaju77F&md5=40dc243e7e37716d63287fc669f76eecElectro-Optical Properties and Structural Stability Perspectives of M3N and M2C2 (M = Sc, La) Clusters Encapsulated in B80 Fullerene: A Density Functional Theory StudyMahdavifar, Zabiollah; Ershadifar, Mina; Farrokhnia, AbdolhadiJournal of Electronic Materials (2018), 47 (1), 550-565CODEN: JECMA5; ISSN:0361-5235. (Springer)In this work, the stability of metal nitride/carbide cluster borofullerenes, namely M3N@B80/M2C2@B80, by means of d. functional theory (DFT) were evaluated. Detailed studies on M3N@B80/M2C2@B80 (M = Sc, La) series indicate that these structures have high thermodn. and kinetic stability due to the large value of calcd. embedding energies and HOMO-LUMO (H-L) energy gaps which indicate that the Sc3N, Sc2C2, La3N and La2C2 clusters can form viable stable complexes with B80 fullerene. Our computations show the Sc3N@B80 borofullerene has the highest thermodn. and kinetic stability and the obtained trend for thermodn. stability is Sc3N@B80 > Sc2C2@B80 > La2C2@B80 > La3N@B80. This trend is nearly the same as obtained for the kinetic stability trend; Sc3N@B80 > Sc2C2@B80 > La3N@B80 > La2C2@B80. The H-L energy gap of Sc3N@B80 and Sc2C2@B80 are 1.45 eV and 1.39 eV resp., much larger than La3@B80 (1.18 eV) and La2C2@B80 (1.13 eV), confirming that the nitride and carbide cluster borofullerenes have relatively high kinetic stability and could be isolated exptl. Also, substitution of Sc with La metal in the nitride and carbide clusters imposes a noticeable influence on the stability and electronic properties of M3N@B80/M2C2@B80 structures. Analyses of electronic structure and nearest distance between clusters and fullerene reveal that both covalent and ionic interactions coexist between cluster and boron atoms. Esp. in the case of La2C2@B80, the plausible electron configuration of it is [(La2C2)2-@B802+]. Addnl., the simulated adsorption spectra considered by means of time-dependent DFT calcns. as well as CD spectra show some different absorption bands in a broad region, which is helpful to further exptl. characterization. These results can promise some valuable assistance for the exptl. synthesis of M3N/M2C2@B80 structures because of high thermodn. and kinetic stability.
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298Muya, J. T.; Lijnen, E.; Nguyen, M. T.; Ceulemans, A. Encapsulation of small base molecules and tetrahedral/cubane-like clusters of group V atoms in the boron buckyball: A density functional theory study. J. Phys. Chem. A 2011, 115, 2268– 2280, DOI: 10.1021/jp107630q298https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisFWlsrg%253D&md5=505798be5e61811e4af364129cfd7562Encapsulation of Small Base Molecules and Tetrahedral/Cubane-Like Clusters of Group V Atoms in the Boron Buckyball: A Density Functional Theory StudyMuya, Jules Tshishimbi; Lijnen, Erwin; Nguyen, Minh Tho; Ceulemans, ArnoutJournal of Physical Chemistry A (2011), 115 (11), 2268-2280CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)A d. functional theory study of small base mols. and tetrahedral and cubane-like group V clusters encapsulated in B80 shows that the boron buckyball is a hard acid and prefers hard bases like NH3 or N2H4 to form stable off-centered complexes. In contrast, tetrahedral and cubane-like clusters of this family are metastable in the cage. The most favorable clusters are the mixed tetrahedral and cubane clusters formed by nitrogen and phosphorus atoms such as P2N2@B80, P3N@B80, and P4N4@B80. The boron cap atoms are electrophilic centers, and prefer mainly to react with electron rich nucleophilic sites. The stability of the complexes will be governed by the size and electron donating character of the encapsulated clusters. B80 forms stable complexes with hard materials where a bidentate interaction of the encapsulated mol. with two boron cap atoms is preferred over a single direct complex toward a single endohedral boron.
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299Wang, J.-T.; Chen, C.; Wang, E. G.; Wang, D.-S.; Mizuseki, H.; Kawazoe, Y. Highly stable and symmetric boron caged B@Co12@B80 core-shell cluster. Appl. Phys. Lett. 2009, 94, 133102, DOI: 10.1063/1.3111444299https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXksVeksrk%253D&md5=27290419a0a6e1bb234cd2cbb0e7c0ceHighly stable and symmetric boron caged B@Co12@B80 core-shell clusterWang, Jian-Tao; Chen, Changfeng; Wang, E. G.; Wang, Ding-Sheng; Mizuseki, H.; Kawazoe, Y.Applied Physics Letters (2009), 94 (13), 133102/1-133102/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The geometry, stability, and electronic properties of B@Co12@Bn and Co13@Bn clusters with a wide range n=55 up to 92 are studied by ab initio calcns. We find that B@Co12@B80 and Co13@B80 with closed B80 shell are two stable magic clusters with nearly perfect icosahedral symmetry, and B@Co12@B80 is more stable than Co13@B80 energetically. The strong core-shell bonding yields a very large energy gain of ∼30 eV. This high stability is attributed to the favorable closed-shell at. and electronic structures. The B@Co12@B80 exhibits a large highest occupied and lowest unoccupied energy gap (0.96 eV) that is close to the value for isolated B80 fullerene. (c) 2009 American Institute of Physics.
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300Zhai, H.-J.; Zhao, Y.-F.; Li, W.-L.; Chen, Q.; Bai, H.; Hu, H.-S.; Piazza, Z. A.; Tian, W.-J.; Lu, H.-G.; Wu, Y.-B. Observation of an all-boron fullerene. Nat. Chem. 2014, 6, 727– 731, DOI: 10.1038/nchem.1999300https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFygs7bJ&md5=740edf096553b09227c842cb3cbff427Observation of an all-boron fullereneZhai, Hua-Jin; Zhao, Ya-Fan; Li, Wei-Li; Chen, Qiang; Bai, Hui; Hu, Han-Shi; Piazza, Zachary A.; Tian, Wen-Juan; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Wei, Guang-Feng; Liu, Zhi-Pan; Li, Jun; Li, Si-Dian; Wang, Lai-ShengNature Chemistry (2014), 6 (8), 727-731CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)After the discovery of fullerene-C60, it took almost two decades for the possibility of boron-based fullerene structures to be considered. So far, there has been no exptl. evidence for these nanostructures, in spite of the progress made in theor. investigations of their structure and bonding. Here we report the observation, by photoelectron spectroscopy, of an all-boron fullerene-like cage cluster at B40- with an extremely low electron-binding energy. Theor. calcns. show that this arises from a cage structure with a large energy gap, but that a quasi-planar isomer of B40- with two adjacent hexagonal holes is slightly more stable than the fullerene structure. In contrast, for neutral B40 the fullerene-like cage is calcd. to be the most stable structure. The surface of the all-boron fullerene, bonded uniformly via delocalized σ and π bonds, is not perfectly smooth and exhibits unusual heptagonal faces, in contrast to C60 fullerene.
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301Chen, Q.; Li, W.-L.; Zhao, Y.-F.; Zhang, S.-Y.; Hu, H.-S.; Bai, H.; Li, H.-R.; Tian, W.-J.; Lu, H.-G.; Zhai, H.-J. Experimental and theoretical evidence of an axially chiral borospherene. ACS Nano 2015, 9, 754– 760, DOI: 10.1021/nn506262c301https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFeiu7nE&md5=fcf2a14cc55c04476918cb1bbce491ecExperimental and Theoretical Evidence of an Axially Chiral BorosphereneChen, Qiang; Li, Wei-Li; Zhao, Ya-Fan; Zhang, Su-Yan; Hu, Han-Shi; Bai, Hui; Li, Hai-Ru; Tian, Wen-Juan; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-Dian; Li, Jun; Wang, Lai-ShengACS Nano (2015), 9 (1), 754-760CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Chirality plays an important role in chem., biol., and materials science. The recent discovery of the B40-/0 borospherenes marks the onset of a class of boron-based nanostructures. Here we report the observation of axially chiral borospherene in the B39- nanocluster on the bases of photoelectron spectroscopy, global min. searches, and electronic structure calcns. Extensive structural searches in combination with d. functional and CCSD(T) calcns. show that B39- has a C3 cage global min. with a close-lying C2 cage isomer. Both the C3 and C2 B39- cages are chiral with degenerate enantiomers. The C3 global min. consists of three hexagons and three heptagons around the vertical C3 axis. The C2 isomer is built on two hexagons on the top and at the bottom of the cage with four heptagons around the waist. Both the C3 and C2 axially chiral isomers of B39- are present in the expt. and contribute to the obsd. photoelectron spectrum. The chiral borospherenes also exhibit three-dimensional aromaticity, featuring σ and π double delocalization for all valence electrons. Mol. dynamics simulations reveal that these chiral B39- cages are structurally fluxional above room temp., compared to the highly robust D2d B40 borospherene. The current findings add chiral members to the borospherene family and indicate the structural diversity of boron-based nanomaterials.
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302Wang, Y.-J.; Zhao, Y.-F.; Li, W.-L.; Jian, T.; Chen, Q.; You, X.-R.; Ou, T.; Zhao, X.-Y.; Zhai, H.-J.; Li, S.-D. Observation and characterization of the smallest borospherene, B28– and B28. J. Chem. Phys. 2016, 144, 064307, DOI: 10.1063/1.4941380302https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XisVansro%253D&md5=443d6f22cd9243c4b7af3ec212f80711Observation and characterization of the smallest borospherene, B28- and B28Wang, Ying-Jin; Zhao, Ya-Fan; Li, Wei-Li; Jian, Tian; Chen, Qiang; You, Xue-Rui; Ou, Ting; Zhao, Xiao-Yun; Zhai, Hua-Jin; Li, Si-Dian; Li, Jun; Wang, Lai-ShengJournal of Chemical Physics (2016), 144 (6), 064307/1-064307/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Free-standing boron nanocages or borospherenes have been obsd. recently for B40- and B40. There is evidence that a family of borospherenes may exist. However, the smallest borospherene is still not known. Here, we report exptl. and computational evidence of a seashell-like borospherene cage for B28- and B28. Photoelectron spectrum of B28- indicated contributions from different isomers. Theor. calcns. showed that the seashell-like B28- borospherene is competing for the global min. with a planar isomer and it is shown to be present in the cluster beam, contributing to the obsd. photoelectron spectrum. The seashell structure is found to be the global min. for neutral B28 and the B28- cage represents the smallest borospherene obsd. to date. It is composed of two triangular close-packed B15 sheets, interconnected via the three corners by sharing two boron atoms. The B28 borospherene was found to obey the 2(n + 1)2 electron-counting rule for spherical aromaticity. (c) 2016 American Institute of Physics.
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303Lv, J.; Wang, Y.; Zhu, L.; Ma, Y. B38: An all-boron fullerene analogue. Nanoscale 2014, 6, 11692– 11696, DOI: 10.1039/C4NR01846J303https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFSgtLnO&md5=266ad562f1ec6aca93205054e82d6d68B38: an all-boron fullerene analogueLv, Jian; Wang, Yanchao; Zhu, Li; Ma, YanmingNanoscale (2014), 6 (20), 11692-11696CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Fullerene-like structures formed by elements other than carbon have long been sought. Finding all-boron (B) fullerene-like structures is challenging due to the geometrical frustration arising from competitions among various structural motifs. We report here the prediction of a B38 fullerene analog found through first-principles swarm structure searching calcns. The structure is highly sym. and consists of 56 triangles and four hexagons, which provide an optimal void in the center of the cage. Energetically, it is more favorable than the planar and tubular structures, and possesses an unusually high chem. stability: a large energy gap (∼2.25 eV) and a high double aromaticity, superior to those of most arom. quasi-planar B12 and double-ring B20 clusters. Our findings represent a key step forward towards to the understanding of structures of medium-sized B clusters and map out the exptl. direction of the synthesis of an all-B fullerene analog.
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304BaáTai, T.; ThoáNguyen, M. A new chiral boron cluster B44 containing nonagonal holes. Chem. Commun. 2016, 52, 1653– 1656, DOI: 10.1039/C5CC09111JThere is no corresponding record for this reference.
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305Xu, Q.; Liu, C.; Yang, L.; Jin, P.; Tang, C.; Chen, Z. Computational investigation on MBn (M = Li-Cs, Be-Ba, Sc-La and Ti; n = 28 and 38). J. Mol. Model. 2016, 22, 184, DOI: 10.1007/s00894-016-3055-4305https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2s3hsVaqsQ%253D%253D&md5=e5b2f3ef9129942bf9ce1184a4223055Computational investigation on MB n (M = Li-Cs, Be-Ba, Sc-La and Ti; n = 28 and 38)Xu Qianhui; Liu Chang; Yang Le; Jin Peng; Tang Chengchun; Chen ZhongfangJournal of molecular modeling (2016), 22 (8), 184 ISSN:.Differing from the weakly antiaromatic B80 buckyball, the medium-sized C 1-B28 and D 2h -B38, as well as their mono- to tetra-anions, are highly aromatic, as indicated by the negative nucleus-independent chemical shifts (NICSs) at their cage centers. The interior cavities and high aromaticity of the B28 and B38 cages render them very promising hosts to accommodate diverse metal atoms. Accordingly, we carried out systematic density functional theory (DFT) computations on the structures, stabilities and electronic properties of metalloborofullerenes MB n (M = Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Sc, Y, La and Ti; n = 28 and 38). Among them, besides the recently reported M@B38(M = Sc, Y and Ti) [Lu et al. (2015) Phys Chem Chem Phys 17:20897-20902], Ti@B28 and M@B38 (M = Ca and La) also favor endohedral structures with large binding energies, and are suggested promising targets for experimental applications. Note that Ti@B28 is the first endohedral derivative based on the new B28 fullerene, and La@B38 features the largest metal size inside a B38 cage thus far. These endohedral derivatives, as exemplified by Ca@B38, may exhibit σ and π double aromaticity over the whole cage surface, indicating their considerable stability. In contrast, the other metals prefer to reside at the exterior cage surface, due mainly to the mismatch of their sizes with the boron cages, though the size match is not the only factor to determine their doping form. Furthermore, the infrared absorption spectra and (11)B nuclear magnetic resonance spectra of the three new M@B n complexes were computed to assist future experimental characterization. Graphical Abstract Putting more metals into medium-sized boron cages!
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306Bai, H.; Chen, Q.; Zhai, H. J.; Li, S. D. Endohedral and exohedral metalloborospherenes: M@B40 (M = Ca, Sr) and M&B40 (M = Be, Mg). Angew. Chem., Int. Ed. 2015, 54, 941– 945, DOI: 10.1002/anie.201408738306https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFKmtLnF&md5=26b2441461fee9e44098c193df5633ceEndohedral and Exohedral Metalloborospherenes: M@B40 (M = Ca, Sr) and M&B40 (M = Be, Mg)Bai, Hui; Chen, Qiang; Zhai, Hua-Jin; Li, Si-DianAngewandte Chemie, International Edition (2015), 54 (3), 941-945CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The recent discovery of the all-boron fullerenes or borospherenes, D2d B40-/0, paves the way for borospherene chem. Here we report a d. functional theory study on the viability of metalloborospherenes: endohedral M@B40 (M = Ca, Sr) and exohedral M and B40 (M = Be, Mg). Extensive global structural searches indicate that Ca@B40 (1, C2v, 1A1) and Sr@B40 (3, D2d, 1A1) possess almost perfect endohedral borospherene structures with a metal atom at the center, while Be and B40 (5, Cs, 1A') and Mg and B40 (7, Cs, 1A') favor exohedral borospherene geometries with a η7-M atom face-capping a heptagon on the waist. Metalloborospherenes provide indirect evidence for the robustness of the borospherene structural motif. The metalloborospherenes are characterized as charge-transfer complexes (M2+B402-), where an alk. earth metal atom donates two electrons to the B40 cage. The high stability of endohedral Ca@B40 (1) and Sr@B40 (3) is due to the match in size between the host cage and the dopant. Bonding analyses indicate that all 122 valence electrons in the systems are delocalized as σ or π bonds, being distributed evenly on the cage surface, akin to the D2d B40 borospherene.
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307Jin, P.; Hou, Q.; Tang, C.; Chen, Z. Computational investigation on the endohedral borofullerenes M@B40 (M = Sc, Y, La). Theor. Chem. Acc. 2015, 134, 13, DOI: 10.1007/s00214-014-1612-4There is no corresponding record for this reference.
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308Fa, W.; Chen, S.; Pande, S.; Zeng, X. C. Stability of metal-encapsulating boron fullerene B40. J. Phys. Chem. A 2015, 119, 11208– 11214, DOI: 10.1021/acs.jpca.5b07173308https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1yltrfP&md5=dfbbe68e8613fbd2bbfd2d2b389f7c5bStability of Metal-Encapsulating Boron Fullerene B40Fa, Wei; Chen, Shuang; Pande, Seema; Zeng, Xiao ChengJournal of Physical Chemistry A (2015), 119 (45), 11208-11214CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The structural stability of MB40 (M = Li, Na, K, Ba, and Tl) is investigated on the basis of d.-functional theory calcns. at the PBE0 level. Particular attention is placed on the relative stability between the endohedral and exohedral configurations of metalloborospherenes. It is found that the Na and Ba atoms can be stably encapsulated inside the B40 cage, whereas the Li, K, and Tl atoms favor the exohedral configuration where the dopant caps one of heptagons of B40 cage. In-depth anal. of the endohedral vs. exohedral configurations with different dopants suggests that besides the comparable at. size with the cage size, another key factor that can affect stability of endohedral vs. exohedral configuration is the interaction between the dopant and B atoms. The IR spectra of the endohedral C2v Na@B40 and exohedral Cs Na&B40 clusters are also computed, from which some useful spectral indicators may be used for identification of the structures in the future expts.
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309Shah, E. V.; Roy, D. R. Sc3N and Sc2C2 encapsulated B40: Smarter than its carbon analogue. Phys. E 2016, 84, 354– 360, DOI: 10.1016/j.physe.2016.08.002309https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhtlegs7vI&md5=d908e2eb88e70a9b2755af3f7b5b8773Sc3N and Sc2C2 encapsulated B40: Smarter than its carbon analogueShah, Esha V.; Roy, Debesh R.Physica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2016), 84 (), 354-360CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)A detailed comparative investigation on the recently synthesized B40 and C40 along with their metal nitride (Sc3N)and carbide (Sc2C2) encapsulated endohedral fullerenes, is performed under d. functional theory for the first time. The structures, electronic, thermodn. and magnetic properties of all the considered compds. are explored in detail. The present study identifies borospherene (B40) and its encapsulated nitride (Sc3N@B40) and carbide (Sc2C2@B40) endohedral borofullerenes as the better candidates for future novel nano-applications compared to their carbon bucky ball analogs.
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310Shakerzadeh, E.; Biglari, Z.; Tahmasebi, E. M@B40 (M = Li, Na, K) serving as a potential promising novel NLO nanomaterial. Chem. Phys. Lett. 2016, 654, 76– 80, DOI: 10.1016/j.cplett.2016.05.014310https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XnvFaisb4%253D&md5=974937c96f3d733c328a5a324104bba2M@B40 (M = Li, Na, K) serving as a potential promising novel NLO nanomaterialShakerzadeh, Ehsan; Biglari, Zeinab; Tahmasebi, ElhamChemical Physics Letters (2016), 654 (), 76-80CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)D. functional theory (DFT) calcns. have carried out to investigate the nonlinear optical response of the B40 fullerene by interaction with the alkali metals (Li, Na, K). The results reveal that the interacted fullerenes are energetically favorable. The B40 electronic properties are strongly sensitive to the interaction with the alkali metals. Furthermore, the adsorption of the alkali metals over the B40 hexagonal ring remarkably enhances the first hyperpolarizability up to 23111.72 a.u. Therefore, the B40 fullerene interacted with the alkali metals could be introduced as a promising innovative nonlinear optical boron-based nanomaterial.
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311Li, S.-X.; Zhang, Z.-P.; Long, Z.-W.; Qin, S.-J. Structures, stabilities and spectral properties of metalloborospherenes MB0/–40 (M = Cu, Ag, and Au). RSC Adv. 2017, 7, 38526– 38537, DOI: 10.1039/C7RA05932A311https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1yhsL3K&md5=4835c9398413c9f0065dcc587c9f379cStructures, stabilities and spectral properties of metalloborospherenes MB0/-40 (M = Cu, Ag, and Au)Li, Shi-Xiong; Zhang, Zheng-Ping; Long, Zheng-Wen; Qin, Shui-JieRSC Advances (2017), 7 (61), 38526-38537CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The discovery of borospherene B40 marks the onset of a new class of boron fullerenes and it is of current interest in chem. physics and, in particular, boron chem. In this work, d. functional theory (DFT) and time-dependent d. functional theory (TD-DFT) calcns. are carried out to study the structures, stabilities, photoelectron spectra, IR spectra, Raman spectra and electronic absorption spectra of metalloborospherenes MB0/-40 (M = Cu, Ag, and Au). It is found that Cu, Ag and Au atoms can form stable exohedral metalloborospherenes M&B0/-40 (M = Cu, Ag, and Au) and endohedral metalloborospherenes M@B0/-40 (M = Cu, Ag, and Au). In addn., the relative energies of these metalloborospherenes suggest that Cu, Ag and Au atoms favor the exohedral configuration. The Cu atom favors an exohedral geometry with the dopant face-capping a heptagon on the side surface (η7-Cu), whereas Ag and Au atoms favor exohedral geometries with the dopant bonding a side boron atom of the hexagonal ring. The calcd. spectra suggest that doping of metal atoms in borospherene B40 can change the spectral features since the extra metal atoms can modify the electronic structure of borospherene B40. The addn. of metal atoms can lead to more IR and Raman active modes and red shift the electronic absorption spectra. The calcd. results also show that metalloborospherenes MB0/-40 (M = Cu, Ag, and Au) have different and meaningful spectral features, insight into the spectral properties is important to understand the compds. and reveal their potential applications. These spectral features can be readily compared with future spectroscopy measurements and used as fingerprints to identify and distinguish the metalloborospherenes MB0/-40 (M = Cu, Ag, and Au).
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312Jin, P.; Yang, L.; Liu, C.; Hou, Q.; Li, L. Computational prediction of the endohedral metalloborofullerenes Tin@B40 (n = 1, 2). Theor. Chem. Acc. 2017, 136, 56, DOI: 10.1007/s00214-017-2087-xThere is no corresponding record for this reference.
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313Xi, C.; Yang, L.; Liu, C.; You, P.; Li, L.; Jin, P. Lanthanide metals in the boron cages: Computational prediction of M@Bn (M = Eu, Gd; n = 38, 40). Int. J. Quantum Chem. 2018, 118, e25576 DOI: 10.1002/qua.25576There is no corresponding record for this reference.
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314Yong, Y.; Su, X.; Kuang, Y.; Li, X.; Lu, Z. B40 and M@B40 (M = Li and Ba) fullerenes as potential molecular sensors for acetone detection A first-principles study. J. Mol. Liq. 2018, 264, 1– 8, DOI: 10.1016/j.molliq.2018.05.046314https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXpsVajsb4%253D&md5=a335b7e0ea6029863f2713bd639211e7B40 and M@B40 (M=Li and Ba) fullerenes as potential molecular sensors for acetone detection: A first-principles studyYong, Yongliang; Su, Xiangying; Kuang, Yanmin; Li, Xiaohong; Lu, ZhanshengJournal of Molecular Liquids (2018), 264 (), 1-8CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)The adsorption of acetone on B40 and M@B40 (M=Li and Ba) has been studied by means of d. functional theory calcns. It is demonstrated that the acetone mol. can easily chemisorb on the B40 and M@B40 from physisorption states with very small energy barriers. The adsorption strength is moderate and the charge transfer between acetone and B40 (or M@B40) is apparent. Moreover, the M-doping can slightly enhance the adsorption strength. The elec. cond. of B40 (or M@B40) changes obviously due to the acetone adsorption. The recovery times for B40 or M@B40, in particular for B40 at T = 300 K are quite short, very different from NH3 or NO2 adsorbed on B40. Our results suggest that the B40 and M@B40 (M=Li and Ba) can be viewed as high sensitive mol. sensors for acetone detection with short recovery time.
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315Yu, T.; Gao, Y.; Xu, D.; Wang, Z. Actinide endohedral boron clusters: A closed-shell electronic structure of U@B40. Nano Res. 2018, 11, 354– 359, DOI: 10.1007/s12274-017-1637-9315https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtlygurvF&md5=84944c022eb618519902981e6cdd6f53Actinide endohedral boron clusters: A closed-shell electronic structure of U@B40Yu, Tianrong; Gao, Yang; Xu, Dexuan; Wang, ZhigangNano Research (2018), 11 (1), 354-359CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)The distinctive electronic bonding properties of actinide-contg. clusters have made them the subject of increased attention. Herein, we use d. functional theory calcns. to examine a unique actinide-encapsulated U@B40 cage structure, revealing that it exhibits a 32-electron (1S21P61D101F14) closed-shell singlet configuration in which all s, p, d, and f shells of the U atom are filled. Furthermore, the binding energy of 8.22 eV calcd. for this cluster implies considerable stability, and the simulated IR and Raman spectra feature U-B40 stretching and pure B40 breathing vibration modes, resp. These spectral characteristics may aid future exptl. investigations. Thus, this work not only describes a new member of the superat. family, but also provides a method of encapsulating radioactive actinides. [Figure not available: see fulltext.].
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316Chojecki, M.; Yourdkhani, S.; Rutkowska-Zbik, D.; Korona, T. Stability of endo-and exohedral complexes of all-boron fullerene B40. Comput. Theor. Chem. 2018, 1133, 7– 17, DOI: 10.1016/j.comptc.2018.04.007316https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXotlGntr8%253D&md5=99d610fb0d8685fc65e1db3ada9c963fStability of endo- and exohedral complexes of all-boron fullerene B40Chojecki, Michal; Yourdkhani, Sirous; Rutkowska-Zbik, Dorota; Korona, TatianaComputational & Theoretical Chemistry (2018), 1133 (), 7-17CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)In a recent publication [Nature Chem., 6, 727 (2014)] the synthesis and properties of a new all-boron fullerene analog, B40, have been reported, and a possibility of utilizing the B40 mol. as a hydrogen storage has been postulated. Therefore, in this contribution we study the stability of endo- and exohedral complexes with the hydrogen mol. and several other small mols., such as N2, H2O, and CO2. The examn. of binding and interaction energies obtained by symmetry-adapted perturbation theory and by supermol. approaches shows that among the studied endohedral complexes only the one with H2 inside the cage is possibly weakly stabilized by the complexation, while all other mols. clearly exhibit too large repulsion, which cannot be counterweighted by attractive components of the interaction energy. An addn. of the zero-point vibrational correction to the H2@B40 binding energy changes the balance of the attractive and repulsive contributions in favor of repulsion, so that finally also this endohedral complex is thermodynamically unstable at zero Kelvin. The exohedral min. are stable in all the cases, and are mostly bound by dispersion.
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317Maniei, Z.; Shakerzadeh, E.; Mahdavifar, Z. Theoretical approach into potential possibility of efficient NO2 detection via B40 and Li@B40 fullerenes. Chem. Phys. Lett. 2018, 691, 360– 365, DOI: 10.1016/j.cplett.2017.11.045317https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVygtb3P&md5=e929619105180d608ddf1a2ce99da717Theoretical approach into potential possibility of efficient NO2 detection via B40 and Li@B40 fullerenesManiei, Zeinab; Shakerzadeh, Ehsan; Mahdavifar, ZabiollahChemical Physics Letters (2018), 691 (), 360-365CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The potential applicability of B40 and Li@B40 fullerenes as chem. sensors for NO2 pollutant detection was studied by employing DFT calcns. NO2 mol. is remarkably chemisorbed on the surface of both B40 and Li@B40 fullerenes. Electronic properties of B40 and Li@B40 fullerenes change after NO2 chemisorption. Although the HOMO-LUMO energies gap (HLG) of B40 is considerably decreased after NO2 chemisorption, the HLG of Li@B40 are significantly enhanced after NO2 adsorption. B40 and Li@B40 fullerenes are introduced as novel promising chem. sensor for NO2 pollutant.
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318An, Y.; Zhang, M.; Wu, D.; Fu, Z.; Wang, T.; Xia, C. Electronic transport properties of the first all-boron fullerene B40 and its metallofullerene Sr@B40. Phys. Chem. Chem. Phys. 2016, 18, 12024– 12028, DOI: 10.1039/C6CP01096B318https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XkvFOnurw%253D&md5=5b7dba58890b5043711fb12d9eed5902Electronic transport properties of the first all-boron fullerene B40 and its metallofullerene Sr@B40An, Yipeng; Zhang, Mengjun; Wu, Dapeng; Fu, Zhaoming; Wang, Tianxing; Xia, CongxinPhysical Chemistry Chemical Physics (2016), 18 (17), 12024-12028CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The newly-discovered B40 is the first exptl. obsd. all-boron fullerene and has potential applications in mol. devices. Herein, we report the electronic transport properties of B40 and its metallofullerene, Sr@B40, using the first-principles technique. We obtain the conductance of B40 fullerene, which is about 130 μS and can be increased by embedding a strontium metal atom in the cage due to the decreased energy gap. Both the current-voltage (I-V) curves of B40 and Sr@B40 present perfect linear characteristics. Intuitively, it is assumed that the electron currents pass through the B40 fullerene mainly along the surface B-B bonds, while two types of new B-Sr-B bond currents and B→Sr→B hopping currents are presented for Sr@B40 due to Sr acting as a bridge. This study provides valuable information for the potential applications of future borospherene-based mol. devices.
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319Wang, W.; Guo, Y.-D.; Yan, X.-H. The spin-dependent transport of transition metal encapsulated B40 fullerene. RSC Adv. 2016, 6, 40155– 40161, DOI: 10.1039/C6RA00179C319https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmsF2gurw%253D&md5=aaffc7c58fd759ea8faaee262f098c34The spin-dependent transport of transition metal encapsulated B40 fullereneWang, Wei; Guo, Yan-Dong; Yan, Xiao-HongRSC Advances (2016), 6 (46), 40155-40161CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The all-boron fullerene, B40, has been successfully exptl. synthesized [Zhai et al., Nat. Chem.,6, 727 (2014)]. Compared with C60, the smaller cage-like structure is more suitable to dope with metal atoms. Based on d. functional theory and nonequil. Green's function method, we investigate the spin-dependent transport of transition metal atom-encapsulated B40 fullerene, i.e., X@B40 (X = Fe, Mn, Ni, and Co), which are contacted with Au electrodes. The transmission spectra of Fe- and Mn-doped systems are spin-polarized, and those of Ni-doped ones are spin-unpolarized. Interestingly, in Co-doped systems, the transmission is highly spin-polarized for the hexagonal doping case, but spin-unpolarized for the heptagonal doping case. Further investigation shows that the screening effect of the electrodes on the magnetism of Co is the underlying phys. mechanism, which is found to be robust to the electrode material. We believe that these findings are very useful for developing spintronic devices.
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320Mahdavifar, Z.; Poulad, M. Stability prediction of pristine and metal endohedral borofullerenes: Computational approach. J. Mol. Liq. 2016, 219, 1144– 1156, DOI: 10.1016/j.molliq.2016.03.027320https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xot1SgsbY%253D&md5=4071ab97b4461b205ccfb6ec41d70d43Stability prediction of pristine and metal endohedral borofullerenes: Computational approachMahdavifar, Zabiollah; Poulad, MarziyehJournal of Molecular Liquids (2016), 219 (), 1144-1156CODEN: JMLIDT; ISSN:0167-7322. (Elsevier B.V.)Based on DFT calcns., the structure, stability and electronic properties of pristine borofullerenes (Bn with n = 20, 30, 40, 50, 60) and their endohedral Zn@Bn fullerenes were investigated. The binding energy per atom has been calcd. for pristine Bn, showing that the stability grows with increasing fullerene size, where the most stable structure is related to the B50 fullerene with Eb = - 5.65 eV/atom. The stability of these structures are predicted in the order B50 ∼ B60 > B40 > B30 > B20. On the other hand, the largest H-L energy gap is belonging to the smallest cluster, B20, with energy gap about 1.15 eV. This is an interesting result since it means that the most stable structure for the Bn fullerenes does not necessary have to be a large H-L energy gap. To testify the effect of Zn encapsulation on the stability of Bn fullerenes, the Zn@Bn fullerene are also considered. Due on stabilization energy, the stability of Zn@Bn fullerenes are predicted in the order Zn@B30 > Zn@B20 > Zn@B60 > Zn@B40 > Zn@B50. Based on these results, the encapsulating process has the most influence on B30 and B50 fullerenes. As results, the method of Zn encapsulating is very successful to stabilize small Bn fullerene. In the case of Zn@B50, this structure is extremely unstable whereas the pristine B50 is favorable structure. On the other hand, when the Zn metal atom encapsulated into the fullerenes, a dramatically mutation in Fermi level is occurred which imply to change in energy gap.
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321Wang, C.-Z.; Bo, T.; Lan, J.-H.; Wu, Q.-Y.; Chai, Z.-F.; Gibson, J. K.; Shi, W.-Q. Ultrastable actinide endohedral borospherenes. Chem. Commun. 2018, 54, 2248– 2251, DOI: 10.1039/C7CC09837E321https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit12gsr4%253D&md5=751c5ab59619520c687b2a918f80eda8Ultrastable actinide endohedral borospherenesWang, Cong-Zhi; Bo, Tao; Lan, Jian-Hui; Wu, Qun-Yan; Chai, Zhi-Fang; Gibson, John K.; Shi, Wei-QunChemical Communications (Cambridge, United Kingdom) (2018), 54 (18), 2248-2251CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Since the discovery of the first all-boron fullerenes B40-/0, metal-doped borospherenes have received extensive attention. So far, in spite of theor. efforts on metalloborospherenes, the feasibility of actinide analogs remains minimally explored. Here we report a series of actinide borospherenes AnBn (An = U, Th; n = 36, 38, and 40) using DFT-PBE0 calcns. All the AnBn complexes are found to possess endohedral structures (An@Bn) as the global min. In particular, U@B36 (C2h, 3Ag) and Th@B38 (D2h, 1Ag) exhibit nearly ideal endohedral borospherene structures. The C2h U@B36 and D2h Th@B38 complexes are predicted to be highly robust both thermodynamically and dynamically. In addn. to the actinide size match to the cage, the covalent character of the metal-cage bonding in U@B36 and Th@B38 affords further stabilization. Bonding anal. indicates that U@B36 and Th@B38 can be qualified as 32-electron systems, and Th@B38 exhibits 3D aromaticity with σ plus π double delocalization bonding. The results demonstrate that doping with appropriate actinide atoms is promising to stabilize diverse borospherenes, and may provide routes for borospherene modification and functionalization.
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322Chen, Q.; Li, H.-R.; Tian, W.-J.; Lu, H.-G.; Zhai, H.-J.; Li, S.-D. Endohedral charge-transfer complex Ca@B37–: Stabilization of a B373– borospherene trianion by metal-encapsulation. Phys. Chem. Chem. Phys. 2016, 18, 14186– 14190, DOI: 10.1039/C6CP02369J322https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XntlSmsrg%253D&md5=a702de1ccbed2cade0ccabc0ee5011b0Endohedral charge-transfer complex Ca@B37-: stabilization of a B373- borospherene trianion by metal-encapsulationChen, Qiang; Li, Hai-Ru; Tian, Wen-Juan; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-DianPhysical Chemistry Chemical Physics (2016), 18 (21), 14186-14190CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Based on extensive first-principles theory calcns., DFT-PBE0 and CCSD(T), the authors present results on the endohedral charge-transfer complex, Cs Ca@B37-, which contains a 3D arom. fullerene-like Cs B373- trianion composed of interwoven boron double chains with twelve delocalized multicenter π bonds (12 mc-2e π, m = 5, 6) over a σ skeleton, completing the Bnq borospherene family (q = n - 40) in the size range of n = 36-42.
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323Lu, Q. L.; Luo, Q. Q.; De Li, Y.; Huang, S. G. DFT study on endohedral and exohedral B38 fullerenes: M@B38 (M = Sc, Y, Ti) and M&B38 (M = Nb, Fe, Co, Ni). Phys. Chem. Chem. Phys. 2015, 17, 20897– 20902, DOI: 10.1039/C5CP03378K323https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtF2mtLrL&md5=ed48052dba12354dc15df38823e918edDFT study on endohedral and exohedral B38 fullerenes: M@B38 (M = Sc, Y, Ti) and M&B38 (M = Nb, Fe, Co, Ni)Lu, Qi Liang; Luo, Qi Quan; Li, Yi De; Huang, Shou GuoPhysical Chemistry Chemical Physics (2015), 17 (32), 20897-20902CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures, stabilities and electronic properties of endohedral and exohedral B38 fullerenes with transition metal atoms (M = Sc, Y, Ti, Nb, Fe, Co, Ni) are studied using all-electron d. functional theory. M@B38 (M = Sc, Y, Ti) possess endohedral structures as their lowest energy structures, while Nb, Fe, Co and Ni atoms favor the coordination of B38 fullerenes in an exohedral manner. Sizable HOMO-LUMO gaps and high binding energies imply the viability of M@B38 towards exptl. realization. The distributions of electron d. and frontier orbitals are analyzed in detail. The anal. of vertical ionization potential and vertical electron affinity indicates that M@B38 are good electron acceptors and bad electron donors.
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324Chen, Q.; Li, H.-R.; Miao, C.-Q.; Wang, Y.-J.; Lu, H.-G.; Mu, Y.-W.; Ren, G.-M.; Zhai, H.-J.; Li, S.-D. Endohedral Ca@B38: Stabilization of a B382– borospherene dianion by metal encapsulation. Phys. Chem. Chem. Phys. 2016, 18, 11610– 11615, DOI: 10.1039/C5CP06169E324https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVGgt7nJ&md5=765424a907e795682d6fe7f466d7cbdaEndohedral Ca@B38: stabilization of a B382- borospherene dianion by metal encapsulationChen, Qiang; Li, Hai-Ru; Miao, Chang-Qing; Wang, Ying-Jin; Lu, Hai-Gang; Mu, Yue-Wen; Ren, Guang-Ming; Zhai, Hua-Jin; Li, Si-DianPhysical Chemistry Chemical Physics (2016), 18 (17), 11610-11615CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Based on extensive global-min. searches and first-principles electronic structure calcns., we present the viability of an endohedral metalloborospherene Cs Ca@B38 (1) which contains a Cs B382- (2) dianion composed of interwoven boron double chains with a σ + π double delocalization bonding pattern, extending the Bnq (q = n - 40) borospherene family from n = 39-42 to n = 38. Transition metal endohedral complexes Cs M@B38 (M = Sc, Y, Ti) (3, 5, 7) based on Cs B382-(2) are also predicted.
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325Chen, Q.; Gao, T.; Tian, W.-J.; Bai, H.; Zhang, S.-Y.; Li, H.-R.; Miao, C.-Q.; Mu, Y.-W.; Lu, H.-G.; Zhai, H.-J. Endohedral C3Ca@B39+ and C2Ca@B39+: Axially chiral metalloborospherenes based on B39–. Phys. Chem. Chem. Phys. 2015, 17, 19690– 19694, DOI: 10.1039/C5CP03178H325https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFaiu7vO&md5=2af8055cd0ece518a07e048304b48036Endohedral C3 Ca@B39+ and C2 Ca@B39+: axially chiral metalloborospherenes based on B39-Chen, Qiang; Gao, Ting; Tian, Wen-Juan; Bai, Hui; Zhang, Su-Yan; Li, Hai-Ru; Miao, Chang-Qing; Mu, Yue-Wen; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-DianPhysical Chemistry Chemical Physics (2015), 17 (30), 19690-19694CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Using the newly discovered borospherenes C3 B39- and C2 B39- as mol. devices and based on extensive global-min. searches and first-principles calcns., we present herein the possibility of the first axially chiral metalloborospherenes C3 Ca@B39+ (1, 1A) and C2 Ca@B39+ (2, 1A), which are the global min. and the second lowest-lying isomer of CaB39+, resp. These metalloborospherene species turn out to be charge-transfer complexes Ca2+@B39- in nature, with the Ca center on the C3 or C2 mol. axis donating one electron to the B39 cage which behaves like a superhalogen. MO analyses indicate that C3/C2 Ca2+@B39- possess the universal bonding pattern of σ plus π double delocalization, similar to their C3/C2 B39- parents. Mol. dynamics simulations show that both C3 Ca@B39+ (1) and C2 Ca@B39+ (2) are dynamically stable at 200 K, with the former starting to fluctuate structurally at 300 K and the latter at 400 K, again similar to C3/C2 B39-. The IR and Raman spectra of C3/C2 Ca@B39+ (1/2) are simulated and compared with those of C3/C2 B39- to facilitate their forthcoming exptl. characterization.
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326Stasyuk, A. J.; Solà, M. Does the endohedral borospherene supersalt FLi2@B39 maintain the “super” properties of its subunits?. Phys. Chem. Chem. Phys. 2017, 19, 21276– 21281, DOI: 10.1039/C7CP02550E326https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1WhtrrL&md5=bd2f0664cc66cff5cc9f1f75900d87eaDoes the endohedral borospherene supersalt FLi2@B39 maintain the "super" properties of its subunits?Stasyuk, A. J.; Sola, M.Physical Chemistry Chemical Physics (2017), 19 (32), 21276-21281CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The behavior of the entirely unique system represented by superalkaline species incorporated into a superhalogen cage has been studied using d. functional theory with hybrid functionals and the triple-ξ quality basis set level of theory. The singlet ground state and triplet excited state of an FLi2@B39 borospherene complex as well as its cationic and anionic doublet ground states have been investigated. Only the encapsulation of FLi2+ into B39 in FLi2@B39+ is a thermodynamically unfavorable process. All other systems are stabilized during encapsulation most likely via an unpaired electron delocalization process and electrostatic interaction. The calcns. revealed that superhalogen and superalkaline properties inherent in the sepd. fragments are lost in FLi2@B39 complexes. The applicability of vertically estd. ionization potentials and electron affinities instead of adiabatic ones for description of such systems has been demonstrated.
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327Yang, L.; Jin, P.; Hou, Q.; Li, L. Endohedral metalloborofullerenes M@B44 (M = Ca, Sr, Ba): A computational investigation. J. Mol. Model. 2016, 22, 297, DOI: 10.1007/s00894-016-3170-2327https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sjhtlCmuw%253D%253D&md5=7535d5fced4c87abef0a622b0d7e5988Endohedral metalloborofullerenes M@B44 (M = Ca, Sr, Ba): a computational investigationYang Le; Jin Peng; Hou Qinghua; Li LanlanJournal of molecular modeling (2016), 22 (12), 297 ISSN:.For the first time, the structures, stabilities and electronic properties of alkaline-earth metal doped B44 fullerenes were investigated by means of density functional theory calculations. Our results reveal that M@B44 (M = Ca, Sr, Ba) possess endohedral configurations as their lowest energy structures, whereas the exohedral form is favored when metal is Be or Mg. The large binding energies and sizable HOMO-LUMO gap energies of Ca@B44, Sr@B44 and Ba@B44 suggest the considerable possibility to achieve these novel endohedral borofullerenes experimentally. Born-Oppenheimer molecular dynamics (BO-MD) simulations at various temperatures further confirmed the extreme dynamic stabilities of these endohedral complexes. Their bonding patterns were also analyzed in detail. Finally, we simulated their infrared absorption spectra and (11)B nuclear magnetic resonance spectra to help future structural characterization. Graphical Abstract Stuffing B44 fullerene with metals.
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328Zhao, R.-N.; Yuan, Y.-H.; Han, J.-G.; Duan, Y. Geometries, stabilities, and electronic properties of tungsten encapsulated nanosize irregular Bn (n = 20, 24, 28, and 32) fullerenes: A density functional investigation. Chem. Phys. Lett. 2016, 648, 41– 46, DOI: 10.1016/j.cplett.2016.01.052328https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhtl2rs7o%253D&md5=470beb36f4d1c00ba25a7d57545edda7Geometries, stabilities, and electronic properties of tungsten encapsulated nanosize irregular Bn (n = 20, 24, 28, and 32) fullerenes: A density functional investigationZhao, Run-Ning; Yuan, Yan-Hong; Han, Ju-Guang; Duan, YuhuaChemical Physics Letters (2016), 648 (), 41-46CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Geometries, relative stabilities, and HOMO-LUMO gaps of W@Bn clusters were calcd. using the DFT-mPW3PBE method. The calcd. averaged at. binding energies reveal that the W@B20 has enhanced stability over other clusters. Interestingly, the irregular W@B24 fullerene with bigger HOMO-LUMO gap is supposed to have stronger chem. activity. Moreover, the interactions between W and B24 cage is strongest one based upon the calcd. binding energy between W and B cage. The irregular W@B24 cage is a nonpolar mol.
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329Liu, L.; Osorio, E.; Heine, T. The importance of dynamics studies on the design of sandwich structures: A CrB24 case. Phys. Chem. Chem. Phys. 2016, 18, 18336– 18341, DOI: 10.1039/C6CP02445A329https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xps1amsbs%253D&md5=8ad64f29bd9e0b56d65a1c502e0cecdeThe importance of dynamics studies on the design of sandwich structures: a CrB24 caseLiu, Lei; Osorio, Edison; Heine, ThomasPhysical Chemistry Chemical Physics (2016), 18 (27), 18336-18341CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Computational prediction and design of sandwich structures have drawn a lot of attention because of their interesting bond characteristics and broad applications. Most studies focus on the thermodn. stability. In this study, we performed a series of Born-Oppenheimer mol. dynamics (BO-MD) simulations to investigate the dynamic stability of the well-known sandwich structure CrB24. The aim was to find at which temp. the sandwich structure is stable. The MD results showed that the sandwich structure has an extremely poor dynamic stability. Addnl., one highly sym. endohedral structure with a chromium atom at the center of a B24 cage was found. As a demonstration, we attempted to point out the importance of dynamics studies on the future design of sandwich structures.
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330Li, H.-R.; Liu, H.; Tian, X.-X.; Zan, W.-Y.; Mu, Y.-W.; Lu, H.-G.; Li, J.; Wang, Y.-K.; Li, S.-D. Structural transition in metal-centered boron clusters: From tubular molecular rotors Ta@B21 and Ta@B22+ to cage-like endohedral metalloborospherene Ta@B22–. Phys. Chem. Chem. Phys. 2017, 19, 27025– 27030, DOI: 10.1039/C7CP05179D330https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVOhtbrP&md5=7b2ba443c1dae6f595efd6d11c055c2eStructural transition in metal-centered boron clusters: from tubular molecular rotors Ta@B21 and Ta@B22+ to cage-like endohedral metalloborospherene Ta@B22-Li, Hai-Ru; Liu, Hui; Tian, Xin-Xin; Zan, Wen-Yan; Mu, Yue-Wen; Lu, Hai-Gang; Li, Jun; Wang, Yue-Kui; Li, Si-DianPhysical Chemistry Chemical Physics (2017), 19 (39), 27025-27030CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Inspired by the recent discovery of the metal-centered tubular mol. rotor Cs B2-Ta@B18- with the record coordination no. of CN = 20 and based on extensive first-principles theory calcns., we present herein the possibility of the largest tubular mol. rotors Cs B3-Ta@B18 (1) and C3v B4-Ta@B18+ (2) and smallest axially chiral endohedral metalloborospherenes D2 Ta@B22- (3 and 3'), unveiling a tubular-to-cage-like structural transition in metal-centered boron clusters at Ta@B22- via effective spherical coordination interactions. The highly stable Ta@B22- (3) as an elegant superatom, which features two equiv. corner-sharing B10 boron double chains interconnected by two B2 units with four equiv. B7 heptagons evenly distributed on the cage surface, conforms to the 18-electron configuration with a bonding pattern of σ + π double delocalization and follows the 2(n + 1)2 electron counting rule for spherical aromaticity (n = 2). Its calcd. adiabatic detachment energy of ADE = 3.88 eV represents the electron affinity of the cage-like neutral D2 Ta@B22 which can be viewed as a superhalogen. The IR, Raman, VCD, and UV-vis spectra of the concerned species are computationally simulated to facilitate their spectral characterizations.
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331Li, H.-R.; Liu, H.; Lu, X.-Q.; Zan, W.-Y.; Tian, X.-X.; Lu, H.-G.; Wu, Y.-B.; Mu, Y.-W.; Li, S.-D. Cage-like Ta@Bqn complexes (n = 23–28, q = −1 – + 3) in 18-electron configurations with the highest coordination number of twenty-eight. Nanoscale 2018, 10, 7451– 7456. DOI: 10.1039/C8NR01087K331https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXltFWqsbc%253D&md5=03989b4a840d2c0cd6eef7d395492fa7Cage-like Ta@Bqn complexes (n = 23-28, q = -1-+ 3) in 18-electron configurations with the highest coordination number of twenty-eightLi, Hai-Ru; Liu, Hui; Lu, Xiao-Qin; Zan, Wen-Yan; Tian, Xin-Xin; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Li, Si-DianNanoscale (2018), 10 (16), 7451-7456CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Inspired by recent observations of the highest coordination nos. of CN = 10 in planar wheel-type complexes in D10h Ta@B10- and CN = 20 in double-ring tubular species in D10d Ta@B20- and theor. prediction of the smallest endohedral metalloborospherene D2 Ta@B22- (1) with CN = 22, we present herein the possibility of larger endohedral metalloborospherenes C2 Ta@B23 (2), C2 Ta@B24+ (3), C2v Ta@B24- (4), C1 Ta@B25 (5), D2d Ta@B26+ (6), C2 Ta@B272+ (7), and C2 Ta@B283+ (8) based on extensive first-principles theory investigations. These cage-like Ta@Bqn complexes with B6 pentagonal or B7 hexagonal pyramids on their surface turn out to be the global min. of the systems with CN = 23, 24, 24, 25, 26, 27, and 28, resp., unveiling the highest coordination no. of CN = 28 in spherical environments known in chem. Detailed bonding analyses show that 1-8 as superatoms conform to the 18-electron configuration with a universal σ + π double delocalization bonding pattern. They are effectively stabilized via spd-π coordination interactions between the Ta center and ηn-Bn ligand which match both geometrically and electronically. Such complexes may serve as embryos of novel metal-boride nanomaterials.
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332Rahane, A. B.; Saha, P.; Sukumar, N.; Kumar, V. Smallest Fullerene-like Structures of Boron with Cr, Mo, and W Encapsulation. arXiv:1907.12611 2019.There is no corresponding record for this reference.
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333Minh Tam, N.; Tan Pham, H.; Van Duong, L.; Phuong Pham-Ho, M.; Tho Nguyen, M. Fullerene-like boron clusters stabilized by an endohedrally doped iron atom: BnFe with n = 14, 16, 18 and 20. Phys. Chem. Chem. Phys. 2015, 17, 3000– 3003, DOI: 10.1039/C4CP04279DThere is no corresponding record for this reference.
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334Zhao, L.; Qu, X.; Wang, Y.; Lv, J.; Zhang, L.; Hu, Z.; Gu, G.; Ma, Y. Effects of manganese doping on the structure evolution of small-sized boron clusters. J. Phys.: Condens. Matter 2017, 29, 265401, DOI: 10.1088/1361-648X/aa7190334https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFSjtbjN&md5=aedbf2f1d230bd41df6f068d0876abf4Effects of manganese doping on the structure evolution of small-sized boron clustersZhao, Lingquan; Qu, Xin; Wang, Yanchao; Lv, Jian; Zhang, Lijun; Hu, Ziyu; Gu, Guangrui; Ma, YanmingJournal of Physics: Condensed Matter (2017), 29 (26), 265401/1-265401/7CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Atomic doping of clusters is known as an effective approach to stabilize or modify the structures and properties of resulting doped clusters. We herein report the effect of manganese (Mn) doping on the structure evolution of small-sized boron (B) clusters. The global min. structures of both neutral and charged Mn doped B cluster MnBQn (n = 10-20 and Q = 0, ±1) have been proposed through extensive first-principles swarm-intelligence based structure searches. It is found that Mn doping has significantly modified the grow behaviors of B clusters, leading to two novel structural transitions from planar to tubular and then to cage-like B structures in both neutral and charged species. Half-sandwich-type structures are most favorable for small MnB-/0/+n (n ≤ 13) clusters and gradually transform to Mn-centered double-ring tubular structures at MnB-/0/+16 clusters with superior thermodn. stabilities compared with their neighbors. Most strikingly, endohedral cages become the ground-state structures for larger MnB-/0/+n (n ≥ 19) clusters, among which MnB+20 adopts a highly sym. structure with superior thermodn. stability and a large HOMO-LUMO gap of 4.53 eV. The unique stability of the endohedral MnB+20 cage is attributed to the geometric fit and formation of 18-electron closed-shell configuration. The results significantly advance our understanding about the structure and bonding of B-based clusters and strongly suggest transition-metal doping as a viable route to synthesize intriguing B-based nanomaterials.
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335Wang, Y.; Wu, X.; Zhao, J. Structural evolution and superatoms in molybdenum atom stabilized boron clusters: MoBn (n = 10–24). J. Cluster Sci. 2018, 29, 847– 852, DOI: 10.1007/s10876-018-1369-3335https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmvFKjurc%253D&md5=a1135c202259fef27e7c33590e073516Structural Evolution and Superatoms in Molybdenum Atom Stabilized Boron Clusters: MoBn (n = 10-24)Wang, Yuqing; Wu, Xue; Zhao, JijunJournal of Cluster Science (2018), 29 (5), 847-852CODEN: JCSCEB; ISSN:1040-7278. (Springer)A review. Doping transition metal atom is known as an effective approach to stabilize an at. cluster and modify its structure and electronic properties. We herein report the effect of molybdenum doping on the structural evolution of medium-sized boron clusters. The lowest-energy structures of MoBn (n = 10, 12, 14, 16, 18, 20, 22, 24) clusters are globally searched using genetic algorithm combined with d. functional theory calcns. We found that Mo doping has significantly affected the grow behaviors of Bn clusters, leading to a structural evolution from bowl-like to tubular and finally endohedral cage. The size-dependent binding energy, HOMO-LUMO gap, vertical ionization potential and vertical electron affinity show that MoB12, MoB22 and MoB24 clusters have relatively higher stability and enhanced chem. inertness. More interestingly, the endohedral MoB22 cage is identified as an elegant superatom, which satisfies 18-electron closed shell configuration well.
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336Chen, B.; Sun, W.; Kuang, X.; Lu, C.; Xia, X.; Shi, H.; Gutsev, G. L. Insights into the effects produced by doping of medium-sized boron clusters with ruthenium. Phys. Chem. Chem. Phys. 2018, 20, 30376– 30383, DOI: 10.1039/C8CP05725G336https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitF2qurrJ&md5=947d1cbcb4c3c1bc4ee9ac0bc5e6c407Insights into the effects produced by doping of medium-sized boron clusters with rutheniumChen, Bole; Sun, Weiguo; Kuang, Xiaoyu; Lu, Cheng; Xia, Xinxin; Shi, Hongxiao; Gutsev, Gennady L.Physical Chemistry Chemical Physics (2018), 20 (48), 30376-30383CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Modification of properties of boron nanoparticles by doping with transition metals presents a challenging problem because the no. of isomers of both doped and un-doped nanoparticles rapidly increases with the nanoparticle size. Here, we perform a study of neutral and anionic Ru-doped boron clusters RuBn (n = 9-20) using the unbiased CALYPSO structural search method in combination with d. functional theory calcns. Our results show that the neutral RuB9 cluster possesses a perfect planar wheel-like geometrical structure, whereas the RuBn clusters prefer structures of the half-sandwich type in the range of 10 ≤ n ≤ 14, drum-like type in the range of 15 ≤ n ≤ 18 and cage-like structures for larger n values. The geometrical structures of the lowest total energy states of the RuBn- anions are similar to those of the corresponding neutrals, except for RuB10-, RuB11-, RuB14-, RuB15- and RuB20-. The neutral RuB12 and RuB14 clusters are found to exhibit enhanced stability with respect to the rest of the RuBn clusters due to the delocalized bonding between the Ru atom and the boron host.
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337Shao, X.; Qu, X.; Liu, S.; Yang, L.; Yang, J.; Liu, X.; Zhong, X.; Sun, S.; Vaitheeswaran, G.; Lv, J. Structure evolution of chromium-doped boron clusters: Toward the formation of endohedral boron cages. RSC Adv. 2019, 9, 2870– 2876, DOI: 10.1039/C8RA09143A337https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1Sjtbo%253D&md5=2239e70786af0be43956a0483992381dStructure evolution of chromium-doped boron clusters: toward the formation of endohedral boron cagesShao, Xuecheng; Qu, Xin; Liu, Siyu; Yang, Lihua; Yang, Jinghai; Liu, Xiaohui; Zhong, Xin; Sun, Shuai; Vaitheeswaran, G.; Lv, JianRSC Advances (2019), 9 (5), 2870-2876CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The electron-deficient nature of boron endows isolated boron clusters with a variety of interesting structural and bonding properties that can be further enriched through metal doping. In the current work, we report the structural and electronic properties of a series of chromium-doped boron clusters. The global min. structures for CrBn clusters with an even no. of n ranging from 8 to 22 are proposed through extensive first-principles swarm-intelligence structure searches. Half-sandwich structures are found to be preferred for CrB8, CrB10, CrB12 and CrB14 clusters and to transform to a drum-like structure at CrB16 cluster. Endohedral cage structures with the Cr atom located at the center are energetically most favorable for CrB20 and CrB22 clusters. Notably, the endohedral CrB20 cage has a high symmetry of D2d and a large HOMO-LUMO gap of 4.38 eV, whose stability is attributed to geometric fit and formation of an 18-electron closed-shell configuration. The current results advance our understanding of the structure and bonding of metal-doped boron clusters.
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338Chen, B. L.; Sun, W. G.; Kuang, X. Y.; Lu, C.; Xia, X. X.; Shi, H. X.; Maroulis, G. Structural stability and evolution of medium-sized tantalum-doped boron clusters: A half-sandwich-structured TaB12– cluster. Inorg. Chem. 2018, 57, 343– 350, DOI: 10.1021/acs.inorgchem.7b02585There is no corresponding record for this reference.
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339Saha, P.; Rahane, A. B.; Kumar, V.; Sukumar, N. Electronic origin of the stability of transition-metal-doped B14 drum-shaped boron clusters and their assembly into a nanotube. J. Phys. Chem. C 2017, 121, 10728– 10742, DOI: 10.1021/acs.jpcc.6b10838339https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs12rtLg%253D&md5=ae444ba859944ada9b891e76fd6d3ff0Electronic Origin of the Stability of Transition-Metal-Doped B14 Drum-Shaped Boron Clusters and Their Assembly into a NanotubeSaha, Pinaki; Rahane, Amol B.; Kumar, Vijay; Sukumar, N.Journal of Physical Chemistry C (2017), 121 (20), 10728-10742CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We study the stability of drum-shaped transition metal (TM) doped boron clusters, M@Bn with n = 14 and 16, and M = 3d, 4d, and 5d TM atom using ab initio calcns. Our results show that drum-shaped M@B14 clusters are favored for M = Cr, Mn, Fe, Co, and Ni, while in other cases, open conical or bowl shaped structures become more favorable. The isoelectronic Ni@B14 and Co@B14- clusters have large HOMO-LUMO gaps and these are magic clusters. Their stability has been correlated with the occurrence of magic behavior with 24 valence electrons in a disk jellium model while for Fe@B14 case, the drum structure is deformed and the stability occurs at 22 delocalized valence electrons. The bonding nature in these clusters has been studied by analyzing the electron d. at bond and ring crit. points, the Laplacian distribution of the electron d., the electron localization function, the source function, and electron localization-delocalization indexes, all of which suggest two and three-center σ bonding within and between the two B7 rings, resp., and hybridization between the TM d orbitals and the π bonded MOs of the drum. The IR and Raman spectra of these magic clusters show all real frequencies, suggesting the dynamical stability of the drum-shaped structures. There is a low frequency mode assocd. with the M atom. Results of the electronic spectra of the anion clusters are also presented that may help to identify these species in future expts. Further, we discuss the stability of 24 delocalized valence electron systems Mn@B16 anion, Fe@B16, Co@B16 cation, and other related clusters. Assembly of Co@B14 clusters has been shown to stabilize a carbon nanotube-like nanotube of boron with Co at. nanowire inside while a nanotube of boron with triangular network has been obtained with the assembly of Fe@B16 drum-shaped clusters. Both the nanotubes are metallic.
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340Saha, P.; Rahane, A.; Kumar, V.; Sukumar, N. Analysis of the electron density features of small boron clusters and the effects of doping with C, P, Al, Si, and Zn: Magic B7P and B8Si clusters. Phys. Scr. 2016, 91, 053005, DOI: 10.1088/0031-8949/91/5/053005340https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslChs7%252FF&md5=e657372dcf917ec4b458a19820dfd4a6Analysis of the electron density features of small boron clusters and the effects of doping with C, P, Al, Si, and Zn: Magic B7P and B8Si clustersSaha, P.; Rahane, A. B.; Kumar, V.; Sukumar, N.Physica Scripta (2016), 91 (5), 053005/1-053005/15CODEN: PHSTBO; ISSN:0031-8949. (IOP Publishing Ltd.)Boron at. clusters show several interesting and unusual size-dependent features due to the small covalent radius, electron deficiency, and higher coordination no. of boron as compared to carbon. These include aromaticity and a diverse array of structures such as quasi-planar, ring or tubular shaped, and fullerene-like. In the present work, we have analyzed features of the computed electron d. distributions of small boron clusters having up to 11 boron atoms, and investigated the effect of doping with C, P, Al, Si, and Zn atoms on their structural and phys. properties, in order to understand the bonding characteristics and discern trends in bonding and stability. We find that in general there are covalent bonds as well as delocalized charge distribution in these clusters. We assoc. the strong stability of some of these planar/ quasiplanar disk-type clusters with the electronic shell closing with effectively twelve delocalized valence electrons using a disk-shaped jellium model. B9-, B10, B7P, and B8Si, in particular, are found to be exceptional with very large gaps between the HOMO and the LUMO, and these are suggested to be magic clusters.
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341Popov, I. A.; Jian, T.; Lopez, G. V.; Boldyrev, A. I.; Wang, L.-S. Cobalt-centred boron molecular drums with the highest coordination number in the CoB16– cluster. Nat. Commun. 2015, 6, 8654, DOI: 10.1038/ncomms9654341https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1Gks7bL&md5=975ebfb8e3ecf64dae58346b555ce1e6Cobalt-centered boron molecular drums with the highest coordination number in the CoB16- clusterPopov, Ivan A.; Jian, Tian; Lopez, Gary V.; Boldyrev, Alexander I.; Wang, Lai-ShengNature Communications (2015), 6 (), 8654CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)The electron deficiency and strong bonding capacity of boron led to a vast variety of mol. structures in chem. and materials science. Here the authors report the observation of highly sym. cobalt-centered boron drum-like structures of CoB16- (1), characterized by photoelectron spectroscopy and ab initio calcns. The photoelectron spectra display a relatively simple spectral pattern, suggesting a high symmetry structure. Two nearly degenerate isomers with D8d (i) and C4v (ii) symmetries are found computationally to compete for the global min. These drum-like structures consist of two B8 rings sandwiching a cobalt atom, which has the highest coordination no. known heretofore in chem. Doping of boron clusters with a transition metal atom induces an earlier two-dimensional to three-dimensional structural transition. The CoB16- cluster is tested as a building block in a triple-decker sandwich, suggesting a promising route for its realization in the solid state.
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342Jian, T.; Li, W.-L.; Popov, I. A.; Lopez, G. V.; Chen, X.; Boldyrev, A. I.; Li, J.; Wang, L.-S. Manganese-centered tubular boron cluster–MnB16–: A new class of transition-metal molecules. J. Chem. Phys. 2016, 144, 154310, DOI: 10.1063/1.4946796342https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xms1KmtL4%253D&md5=00228d0798fb62cb2300b930703405d2Manganese-centered tubular boron cluster - MnB16-: A new class of transition-metal moleculesJian, Tian; Li, Wan-Lu; Popov, Ivan A.; Lopez, Gary V.; Chen, Xin; Boldyrev, Alexander I.; Li, Jun; Wang, Lai-ShengJournal of Chemical Physics (2016), 144 (15), 154310/1-154310/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report the observation of a manganese-centered tubular boron cluster (MnB16-), which is characterized by photoelectron spectroscopy and ab initio calcns. The relatively simple pattern of the photoelectron spectrum indicates the cluster to be highly sym. Ab initio calcns. show that MnB16- has a Mn-centered tubular structure with C4v symmetry due to first-order Jahn-Teller effect, while neutral MnB16 reduces to C2v symmetry due to second-order Jahn-Teller effect. In MnB16-, two unpaired electrons are obsd., one on the Mn 3dz2 orbital and another on the B16 tube, making it an unusual biradical. Strong covalent bonding is found between the Mn 3d orbitals and the B16 tube, which helps to stabilize the tubular structure. The current result suggests that there may exist a whole class of metal-stabilized tubular boron clusters. These metal-doped boron clusters provide a new bonding modality for transition metals, as well as a new avenue to design boron-based nanomaterials. (c) 2016 American Institute of Physics.
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343Li, W.; Jian, T.; Chen, X.; Li, H.; Chen, T.; Luo, X.; Li, S.; Li, J.; Wang, L. Observation of a metal-centered B2-Ta@B18– tubular molecular rotor and a perfect Ta@B20– boron drum with the record coordination number of twenty. Chem. Commun. 2017, 53, 1587– 1590, DOI: 10.1039/C6CC09570D343https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFamu7fJ&md5=767c1c68ff585f02edfbad859e7cbd28Observation of a metal-centered B2-Ta@B18- tubular molecular rotor and a perfect Ta@B20- boron drum with the record coordination number of twentyLi, Wan-Lu; Jian, Tian; Chen, Xin; Li, Hai-Ru; Chen, Teng-Teng; Luo, Xue-Mei; Li, Si-Dian; Li, Jun; Wang, Lai-ShengChemical Communications (Cambridge, United Kingdom) (2017), 53 (10), 1587-1590CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A tubular mol. rotor B2-Ta@B18- (1) and boron drum Ta@B20- (2) with the highest coordination no. of twenty in chem. are obsd. via a joint photoelectron spectroscopy and first-principles theory investigation.
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344Li, W.-L.; Chen, X.; Jian, T.; Chen, T.-T.; Li, J.; Wang, L.-S. From planar boron clusters to borophenes and metalloborophenes. Nat. Rev. Chem. 2017, 1, 0071, DOI: 10.1038/s41570-017-0071344https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtVyksbzL&md5=083b9d32bad110ab0f46a60b54b4f469From planar boron clusters to borophenes and metalloborophenesLi, Wan-Lu; Chen, Xin; Jian, Tian; Chen, Teng-Teng; Li, Jun; Wang, Lai-ShengNature Reviews Chemistry (2017), 1 (10), 0071CODEN: NRCAF7; ISSN:2397-3358. (Nature Research)A review. Elemental boron and its compds. exhibit unusual structures and chem. bonding owing to the electron deficiency of boron. Joint photoelectron spectroscopy and theor. studies over the past decade have revealed that boron clusters possess planar or quasi-planar (2D) structures up to relatively large sizes, laying the foundations for the discovery of boron-based nanostructures. The observation of the 2D B36 cluster provided the first exptl. evidence that extended boron monolayers with hexagonal vacancies were potentially viable and led to the proposition of 'borophenes' - boron analogs of 2D carbon structures such as graphene. Metal-doping can expand the range of potential nanostructures based on boron. Recent studies have shown that the CoB18- and RhB18- clusters possess unprecedented 2D structures, in which the dopant metal atom is part of the 2D boron network. These doped 2D clusters suggest the possibilities of creating metal-doped borophenes with potentially tunable electronic, optical and magnetic properties. Here, we discuss the recent exptl. and theor. advances in 2D boron and doped boron clusters, as well as their implications for metalloborophenes.
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345Romanescu, C.; Galeev, T. R.; Li, W.-L.; Boldyrev, A. I.; Wang, L.-S. Transition-metal-centered monocyclic boron wheel clusters (M@Bn): A new class of aromatic borometallic compounds. Acc. Chem. Res. 2013, 46, 350– 358, DOI: 10.1021/ar300149a345https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslOltr7I&md5=bed7702b3865542e2b48d08a274fbf9cTransition-Metal-Centered Monocyclic Boron Wheel Clusters (MBn): A New Class of Aromatic Borometallic CompoundsRomanescu, Constantin; Galeev, Timur R.; Li, Wei-Li; Boldyrev, Alexander I.; Wang, Lai-ShengAccounts of Chemical Research (2013), 46 (2), 350-358CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. Atomic clusters have intermediate properties between that of individual atoms and bulk solids, which provide fertile ground for the discovery of new mols. and novel chem. bonding. In addn., the study of small clusters can help researchers design better nanosystems with specific phys. and chem. properties. From recent exptl. and computational studies, we know that small boron clusters possess planar structures stabilized by electron delocalization both in the σ and π frameworks. An interesting boron cluster is B9-, which has a D8h mol. wheel structure with a single boron atom in the center of a B8 ring. This ring in the D8h-B9- cluster is connected by eight classical two-center, two-electron bonds. In contrast, the cluster's central boron atom is bonded to the peripheral ring through three delocalized σ and three delocalized π bonds. This bonding structure gives the mol. wheel double aromaticity and high electronic stability. The unprecedented structure and bonding pattern in B9- and other planar boron clusters have inspired the designs of similar mol. wheel-type structures. But these mimics instead substitute a heteroatom for the central boron. Through recent expts. in cluster beams, chemists have demonstrated that transition metals can be doped into the center of the planar boron clusters. These new metal-centered monocyclic boron rings have variable ring sizes, MBn and MBn- with n = 8-10. Using size-selected anion photoelectron spectroscopy and ab initio calcns., researchers have characterized these novel borometallic mols. Chemists have proposed a design principle based on σ and π double aromaticity for electronically stable borometallic cluster compds., featuring a highly coordinated transition metal atom centered inside monocyclic boron rings. The central metal atom is coordinatively unsatd. in the direction perpendicular to the mol. plane. Thus, chemists may design appropriate ligands to synthesize the mol. wheels in the bulk. In this Account, we discuss these recent exptl. and theor. advances of this new class of arom. borometallic compds., which contain a highly coordinated central transition metal atom inside a monocyclic boron ring. Through these examples, we show that at. clusters can facilitate the discovery of new structures, new chem. bonding, and possibly new nanostructures with specific, advantageous properties.
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346Zhai, H. J.; Alexandrova, A. N.; Birch, K. A.; Boldyrev, A. I.; Wang, L. S. Hepta-and octacoordinate boron in molecular wheels of eight-and nine-atom boron clusters: Observation and confirmation. Angew. Chem., Int. Ed. 2003, 42, 6004– 6008, DOI: 10.1002/anie.200351874346https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXltlWi&md5=75eff3a71dfa30a2414d5e60b5e0a3e0Hepta- and octacoordinate boron in molecular wheels of eight- and nine-atom boron clusters: Observation and confirmationZhai, Hua-Jin; Alexandrova, Anastassia N.; Birch, K. Alexander; Boldyrev, Alexander I.; Wang, Lai-ShengAngewandte Chemie, International Edition (2003), 42 (48), 6004-6008CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Exptl. and theor. evidence shows that eight- and nine-atom boron clusters are perfectly planar mol. wheels, with a hepta- or octacoordinated central boron atom, resp. (B green). The radii of the miniature mol. wheels are found to be 1.8 and 2.0 Å. Analyses of their chem. bonding reveal that they possess double (σ and π) aromaticity, which is responsible for the wheel structures and the extreme coordination environments.
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347Ito, K.; Pu, Z.; Li, Q.-S.; Schleyer, P. V. R. Cyclic boron clusters enclosing planar hypercoordinate cobalt, iron, and nickel. Inorg. Chem. 2008, 47, 10906– 10910, DOI: 10.1021/ic800993b347https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlSqtLfL&md5=b3c06e5de92b5720f5f040c463a5a84fCyclic Boron Clusters Enclosing Planar Hypercoordinate Cobalt, Iron, and NickelIto, Keigo; Pu, Zhifeng; Li, Qian-Shu; Schleyer, Paul von RagueInorganic Chemistry (2008), 47 (23), 10906-10910CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Planar cyclic boron clusters with cobalt, iron, and nickel atoms at their centers - singlet D8h CoB8-, D9h FeB9-, CoB9, and NiB9+ - were computed to be stable min. at the BP86/TZVPP DFT level. Stochastic searches of the singlet and triplet potential energy surfaces show the planar hypercoordinate D8h CoB8- (1) and D9h FeB9- (2) singlet isomers to be the global min. Their double arom. character with 6 π and 10 radial electrons is documented by detailed NICSzz grid and CMO-NICSzz analyses at PW91/TZVPP. These results encourage gas phase investigations of these two exotic anions. Although isoelectronic with D9h FeB9- (2), CoB9 and NiB9+ prefer nonplanar structures.
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348Chen, T.-T.; Li, W.-L.; Bai, H.; Chen, W.-J.; Dong, X.-R.; Li, J.; Wang, L.-S. Re@B8- and Re@B9-: New members of the transition-metal-centered borometallic molecular wheel family. J. Phys. Chem. A 2019, 123, 5317– 5324, DOI: 10.1021/acs.jpca.9b03942348https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtV2mu7fO&md5=ce17c867b4c78712162a9e06069eeff9ReB8- and ReB9-: New Members of the Transition-Metal-Centered Borometallic Molecular Wheel FamilyChen, Teng-Teng; Li, Wan-Lu; Bai, Hui; Chen, Wei-Jia; Dong, Xin-Ran; Li, Jun; Wang, Lai-ShengJournal of Physical Chemistry A (2019), 123 (25), 5317-5324CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Transition-metal-centered monocyclic boron wheel clusters (MBnq) represent a family of interesting borometallic compds. with double aromaticity. A variety of early and late transition metal atoms have been found to form such structures with high symmetries and various Bn ring sizes. Here we report a combined photoelectron spectroscopy and quantum-chem. theor. study of two MBn- clusters from the middle of the transition metal series: ReB8- and ReB9-. Global min. structure searches revealed that ReB8- adopts a pseudo-C8v structure while ReB9- is a perfectly planar D9h mol. wheel. Chem. bonding analyses showed that both clusters exhibit σ and π double aromaticity and obey the electronic design principle for metal-centered borometallic mol. wheels. The central Re atoms are found to possess unusually low oxidn. states of +I in ReB8- and +II in ReB9-, i.e., the Re atom behaves similarly to late transition metal elements (Ru, Fe, Co, Rh, Ir) in the MBn- mol. wheels. These two clusters become new members of the family of transition-metal-centered monocyclic borometallic mol. wheels, which may be viable for chem. syntheses with appropriate ligands.
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349Galeev, T. R.; Romanescu, C.; Li, W.-L.; Wang, L.-S.; Boldyrev, A. I. Observation of the highest coordination number in planar species: Decacoordinated Ta@B10- and Nb@B10- anions. Angew. Chem., Int. Ed. 2012, 51, 2101– 2105, DOI: 10.1002/anie.201107880349https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslCks7o%253D&md5=bacc5848ef010a6ae3f1c67abf8da7baObservation of the Highest Coordination Number in Planar Species: Decacoordinated Ta©B10- and Nb©B10- AnionsGaleev, Timur R.; Romanescu, Constantin; Li, Wei-Li; Wang, Lai-Sheng; Boldyrev, Alexander I.Angewandte Chemie, International Edition (2012), 51 (9), 2101-2105, S2101/1-S2101/6CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors present photoelectron spectroscopy and theor. (ZORA DFT-PBE0/LANDL2DZ and RCCSD(T)) study of Ta©B10- and Nb©B10- cluster anions. Data are presented on photoelectron spectra, vibrational frequencies of neutral TaB10, isomer geometries, HOMOs and LUMOs, and bonding pattern.
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350Li, W.-L.; Ivanov, A. S.; Federic, J.; Romanescu, C.; Cernusak, I.; Boldyrev, A. I.; Wang, L.-S. On the way to the highest coordination number in the planar metal-centred aromatic Ta@B10- cluster: Evolution of the structures of TaBn- (n = 3-8). J. Chem. Phys. 2013, 139, 104312, DOI: 10.1063/1.4820401350https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVeht7nO&md5=29a5fc0fb58ecba7913be33675551172On the way to the highest coordination number in the planar metal-centred aromatic Ta©B10- cluster: Evolution of the structures of TaBn- (n = 3-8)Li, Wei-Li; Ivanov, Alexander S.; Federic, Jozef; Romanescu, Constantin; Cernusak, Ivan; Boldyrev, Alexander I.; Wang, Lai-ShengJournal of Chemical Physics (2013), 139 (10), 104312/1-104312/13CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures and chem. bonding of TaBn- (n = 3-8) clusters are investigated systematically to elucidate the formation of the planar metal-centered arom. borometallic cluster, Ta©B10- (the © sign is used to designate the central position of the doped atom in monocyclic structures in M©Bn-type planar clusters), which was found previously to have the highest coordination no. for a metal atom in a planar geometry. Photoelectron spectroscopy is combined with ab initio calcns. to det. the global min. of the TaBn- clusters. We find that from TaB3- to TaB5- the boron atoms nucleate around the central Ta atom to form fan-like structures. A structural transition occurs at TaB6-, which is found to have a hexagonal structure, but with a boron atom in the center and the Ta atom on the periphery. TaB7- is shown to have a three-dimensional boat-like structure, which can be viewed as a Ta atom coordinated to an elongated B7 cluster from above. The global min. of the TaB8- cluster is found to be pyramidal with the Ta atom interacting with a B8 monocyclic ring. Starting from this structure, addnl. boron atoms simply enlarge the boron ring to form the slightly pyramidal TaB9- cluster and eventually the perfectly planar Ta-centered B10-ring arom. cluster, Ta©B10-. It is shown that boron atoms do not nucleate smoothly around a Ta atom on the way to the decacoordinated Ta©B10- mol. wheel, but rather the competition between B-B interactions and Ta-B interactions dets. the most stable structures of the smaller TaBn- (n = 3-8) clusters. (c) 2013 American Institute of Physics.
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351Pu, Z.; Ito, K.; Schleyer, P. v. R.; Li, Q.-S. Planar hepta-, octa-, nona-, and decacoordinate first row d-block metals enclosed by boron rings. Inorg. Chem. 2009, 48, 10679– 10686, DOI: 10.1021/ic901377h351https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1yntLzK&md5=4bf04bb869dcc6b6279da5a2ec662fedPlanar Hepta-, Octa-, Nona-, and Decacoordinate First Row d-Block Metals Enclosed by Boron RingsPu, Zhifeng; Ito, Keigo; Schleyer, Paul v. R.; Li, Qian-ShuInorganic Chemistry (2009), 48 (22), 10679-10686CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Possible planar hypercoordinate mols. with first row d-block metal atoms in the centers of boron rings are explored comprehensively by d.-functional theory (DFT) computations. Many optimized MBn (n = 7, 8, 9, and 10) neutral and charged clusters have local Dnh min., although these may not be the most stable isomers. The larger B9 and B10 rings are versatile in accommodating first row d-block metals, whereas the more compact B8 ring only can enclose smaller transition metals (such as Mn, Fe, and Co) effectively. Delocalized π and radial MOs involving boron are crucial in stabilizing these highly sym. planar hypercoordinate mols. Early and middle transition metal d-orbitals participate in metal-boron covalent bonding, whereas partial ionic bonding is more important for the late d-block elements. Potential energy surface scans established several of these species to have planar hypercoordinate global min.: D8h FeB82- was identified here, and D8h CoB8- and D9h FeB9- were identified in an earlier complementary study.
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352Romanescu, C.; Galeev, T. R.; Li, W.-L.; Boldyrev, A. I.; Wang, L.-S. Aromatic metal-centered monocyclic boron rings: Co@B8- and Ru@B9-. Angew. Chem., Int. Ed. 2011, 50, 9334– 9337, DOI: 10.1002/anie.201104166352https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFSltbvF&md5=3a42a6f0494d91f8db2102c6323131c3Aromatic Metal-Centered Monocyclic Boron Rings: CoB8 and RuB9Romanescu, Constantin; Galeev, Timur R.; Li, Wei-Li; Boldyrev, Alexander I.; Wang, Lai-ShengAngewandte Chemie, International Edition (2011), 50 (40), 9334-9337, S9334/1-S9334/4CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Aromaticity is obsd. in the photoelectron spectra of CoB8 and RuB9. This is confirmed in model calcns. of the electron detachment energies.
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353Li, W.-L.; Romanescu, C.; Galeev, T. R.; Piazza, Z. A.; Boldyrev, A. I.; Wang, L.-S. Transition-metal-centered nine-membered boron rings: M@B9 and M@B9- (M = Rh, Ir). J. Am. Chem. Soc. 2012, 134, 165– 168, DOI: 10.1021/ja209808k353https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1SlsrvO&md5=cd0a31e18ba7f04b5d2e69dd5286f921Transition-Metal-Centered Nine-Membered Boron Rings: M©B9 and M©B9- (M = Rh, Ir)Li, Wei-Li; Romanescu, Constantin; Galeev, Timur R.; Piazza, Zachary A.; Boldyrev, Alexander I.; Wang, Lai-ShengJournal of the American Chemical Society (2012), 134 (1), 165-168CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report the observation of two transition-metal-centered nine-atom boron rings, Rh©B9- and Ir©B9-. These two doped-boron clusters are produced in a laser-vaporization supersonic mol. beam and characterized by photoelectron spectroscopy and ab initio calcns. Large HOMO-LUMO gaps are obsd. in the anion photoelectron spectra, suggesting that neutral Rh©B9 and Ir©B9 are highly stable, closed shell species. Theor. calcns. show that Rh©B9 and Ir©B9 are of D9h symmetry. Chem. bonding analyses reveal that these complexes are doubly arom., each with six completely delocalized π and σ electrons, which describe the bonding between the central metal atom and the boron ring. This work establishes firmly the metal-doped B rings as a new class of novel arom. mol. wheels.
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354Kumar, V. Nanosilicon; Elsevier: Amsterdam, 2008.There is no corresponding record for this reference.
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355Zhu, X.; Zeng, X. C. Structures and stabilities of small silicon clusters: Ab initio molecular-orbital calculations of Si7–Si11. J. Chem. Phys. 2003, 118, 3558– 3570, DOI: 10.1063/1.1535906355https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhtVKju7k%253D&md5=de93d12a411f2f535a4437ddf7f8ab15Structures and stabilities of small silicon clusters: Ab initio molecular-orbital calculations of Si7-Si11Zhu, Xiaolei; Zeng, X. C.Journal of Chemical Physics (2003), 118 (8), 3558-3570CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Ab initio all-electron mol.-orbital calcns. have been carried out to study the structure and relative stability of small silicon clusters (Sin, n = 7-11). A no. of low-energy geometric isomers are optimized at the second-order Moller-Plesset (MP2) MP2/6-31G(d) level. Harmonic vibrational anal. has been performed to assure that the optimized geometries are stable. The total energies of stable isomers are computed at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d) level. The calcd. binding energies per atom at both the MP2/6-31G(d) and CCSD(T)/6-31G(d) levels agree with the expts. For Si7, Si8, and Si10, the lowest-energy structures are the same as those predicted previously from the all-electron optimization at the Hartree-Fock (HF) HF/6-31G(d) level [Raghavachari and Rohlfing, J. Chem. Phys. 89, 2219 (1988)]. For Si9, the lowest-energy isomer is same as that predicted based on d.-functional plane-wave pseudopotential method [Vasiliev, Ogut, and Chelikowsky, Phys. Rev. Lett. 78, 4805 (1997)]. Particular attention has been given to Si11 because several low-energy geometric isomers were found nearly isoenergetic. On the basis of MP2/6-311G(2d)//CCSD(T)/6-311G(2d) calcn., we identified that the C2v isomer, a tricapped trigonal prism with two addnl. caps on side trigonal faces, is most likely the global-min. structure. However, another competitive geometric isomer for the global min. is also found on basis of the MP2/6-311G(2d)//CCSD(T)/6-311G(2d) calcn. Addnl., calcns. of the binding energy and the cluster polarizability offer more insights into relatively strong stability of two magic-no. clusters Si6 and Si10.
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356Götz, D.; Heiles, S.; Johnston, R.; Schäfer, R. Note: Gas phase structures of bare Si8 and Si11 clusters from molecular beam electric deflection experiments. J. Chem. Phys. 2012, 136, 186101, DOI: 10.1063/1.4717708356https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38jks1Sgtw%253D%253D&md5=2570e60bb6a7af957afe2eb063f345d5Note: gas phase structures of bare Si8 and Si11 clusters from molecular beam electric deflection experimentsGotz D A; Heiles S; Johnston R L; Schafer RThe Journal of chemical physics (2012), 136 (18), 186101 ISSN:.There is no expanded citation for this reference.
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357Zhao, J.; Ma, L.; Tian, D.; Xie, R. Fullerene-like cage clusters from non-carbon elements. J. Comput. Theor. Nanosci. 2008, 5, 7– 22357https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhvFaqu7w%253D&md5=adc21fe7dd272474c03c259bd4af8228Fullerene-like cage clusters from non-carbon elementsZhao, Jijun; Ma, Li; Tian, Dongxu; Xie, RuihuaJournal of Computational and Theoretical Nanoscience (2008), 5 (1), 7-22CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)A review of recent exptl. and theor. progresses on the search of the fullerene-like nanocages from non-carbon elements. The systems we discussed include medium-sized silicon clusters with endohedral fullerene structures, transition-metal doped silicon cage clusters, fullerene-like nanocages by group V elements (N, P, As, etc.), clusters with nesting doll structures (e.g., [As @ Ni12As20]3-), heterofullerene nanocages by III-V (BN, AlN, GaAs) and II-VI (ZnO, ZnS, ZnSe) compds., and gold fullerene cages at Au32 and Au50, and so on. The stability of each type of non-carbon fullerene nanocages can be understood by some specific mechanism. These non-carbon fullerenes not only represent novel spheroid mols. with interesting structures and properties, but also are potential building blocks for nanostructured materials and devices.
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358Kumar, V.; Kawazoe, Y. Magic behavior of Si15M and Si16M (M = Cr, Mo, and W) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 65, 073404, DOI: 10.1103/PhysRevB.65.073404358https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XhtFSqs70%253D&md5=f0287d16dc8254fc41619d90e2657b8dMagic behavior of Si15M and Si16M (M=Cr, Mo, and W) clustersKumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2002), 65 (7), 073404/1-073404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio electronic-structure calcns. based on pseudopotential plane-wave method and generalized gradient approxn. for the exchange-correlation energy are performed on SinM (n=14-17 and M=Cr, Mo, and W) clusters. We find an M-encapsulated silicon cage M@Si15 derived from a cubic structure to be the optimally close packed for these elements. There are competing growth modes so that a fullerenelike capped cage of Si16M has the lowest energy leading to their simultaneous magic behavior in agreement with expts. The binding energy, the highest occupied-LUMO gap and the embedding energy of M are large, giving rise to their strong stability and complete quenching of the magnetic moment of M. Similar cubic M@Si15 structures are predicted for M=Ti, Hf, Zr, Ru, and Os.
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359Kumar, V.; Majumder, C.; Kawazoe, Y. M@Si16, M = Ti, Zr, Hf: π conjugation, ionization potentials and electron affinities. Chem. Phys. Lett. 2002, 363, 319– 322, DOI: 10.1016/S0009-2614(02)01184-3359https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmvVCms7c%253D&md5=082f853747280d9b29f69938f28cbc0fM@Si16, M = Ti, Zr, Hf: π conjugation, ionization potentials and electron affinitiesKumar, Vijay; Majumder, C.; Kawazoe, YoshiyukiChemical Physics Letters (2002), 363 (3,4), 319-322CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The bonding nature in the fullerene and Frank-Kasper (FK) polyhedral isomers of M@Si16, M = Ti, Zr, and Hf clusters has been studied using ab initio calcns. based on the Gaussian 98 program as well as a ultrasoft pseudopotential plane wave method. The fullerene isomer is found to have double bonds between some Si atoms such that each silicon has two single bonds and a double bond on the cage of these endohedral clusters very similar to C60. There is a mixed sp2-sp3 bonding character between Si atoms and only a small charge transfer from M to the Si cage. The sp2 bonding gives rise to π conjugation. On the other hand in the FK isomer, about three electrons are transferred from M to the Si cage making the bonding nature in this isomer quite different. The ionization potentials of these clusters are large (≈7.5 eV) similar to C60 and the electron affinities are small that make these clusters behave like superatoms.
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360Kumar, V.; Kawazoe, Y. Hydrogenated silicon fullerenes: Effects of H on the stability of metal-encapsulated silicon clusters. Phys. Rev. Lett. 2003, 90, 055502, DOI: 10.1103/PhysRevLett.90.055502360https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXht1ygsLw%253D&md5=c3ad0e9ab0b64f1377bfd4b33b970204Hydrogenated Silicon Fullerenes: Effects of H on the Stability of Metal-Encapsulated Silicon ClustersKumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2003), 90 (5), 055502/1-055502/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Ab initio calcns. of H interaction on Si12M, Si18M2 (M=Cr, Mo, and W), and Zr@Si16 fullerene (f) show relatively weak binding of H in agreement with exptl. results of H free Si12M and Si18M2 clusters. Adsorption of H enhances sp3 bonding between the Si atoms, weakens the M-Si cage interactions, and leads to distortions in the cages. Si12CrH12 has 4μB magnetic moment in contrast to zero for Si12Cr. Removal of the M atom leads to stable empty cages of Si12H12, f-Si16H16, and f-Si20H20 with large highest occupied-LUMO gaps of 2.5-3.0 eV, making them attractive for optoelectronic applications.
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361Kumar, V.; Briere, T. M.; Kawazoe, Y. Ab initio calculations of electronic structures, polarizabilities, Raman and infrared spectra, optical gaps, and absorption spectra of M@Si16 (M = Ti and Zr) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 155412, DOI: 10.1103/PhysRevB.68.155412361https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVSrurc%253D&md5=4a5af3d897b7570d6ea400d177ad820fAb initio calculations of electronic structures, polarizabilities, Raman and infrared spectra, optical gaps, and absorption spectra of M@Si16 (M=Ti and Zr) clustersKumar, Vijay; Briere, Tina M.; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2003), 68 (15), 155412/1-155412/9CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio calcns. were performed using d.-functional theory with the B3PW91 hybrid exchange-correlation functional and the Gaussian method to obtain the electronic and vibrational properties of the fullerene (f) and Frank-Kasper (FK) isomers of the metal-encapsulated Si clusters M@Si16, M = Ti and Zr. The electron affinities of the two isomers differ significantly and the authors' result for FK-Ti@Si16 is in good agreement with recent expts. The Raman and IR vibrational spectra of the f and FK isomers show marked differences, due to their distinct bonding natures and structural features, that can be used unambiguously to identify the structures of these clusters exptl. The polarizabilities, however, have similar values and lie above the bulk limit of Si. The optical gaps and absorption spectra were calcd. using time-dependent d.-functional theory. The lowest electronic excitation for the FK isomer lies in the deep blue region, while the one for the f isomer lies in the red region, making them attractive for optoelectronic applications.
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362Kawamura, H.; Kumar, V.; Kawazoe, Y. Growth, magic behavior, and electronic and vibrational properties of Cr-doped Si clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 245433, DOI: 10.1103/PhysRevB.70.245433362https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXislOqsQ%253D%253D&md5=18ac85e54e947b6e5ab0ee9b5369c788Growth, magic behavior, and electronic and vibrational properties of Cr-doped Si clustersKawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 70 (24), 245433/1-245433/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Silicon clusters doped with a Cr atom have been studied using ab initio plane-wave ultrasoft pseudopotential and Gaussian methods. The most stable structures and magic clusters have been detd. for SinCr (n=8-17) starting from many initial configurations. Our results show that for n=8-11 the no. of Si atoms is not enough to surround a Cr atom fully and therefore the structures of these clusters are basket type in which the Cr atom has a bare part. A cage structure is formed for n = 12 Cr@i12 and Cr@i15 show magic behavior. Among the charged clusters, anion of Cr@i12 and cation of Cr@i13 have high stability. The ionization potentials and electron affinities have been calcd. The dynamical stability of clusters is studied from vibrational calcns. The results of Raman activities and IR intensities are presented for selected clusters. These can be used to identify the structures from expts. The bonding nature in Cr@in clusters is found to change depending on the structure even when the cluster size is the same.
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363Sun, Q.; Wang, Q.; Briere, T.; Kumar, V.; Kawazoe, Y.; Jena, P. First-principles calculations of metal stabilized Si20 cages. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 65, 235417, DOI: 10.1103/PhysRevB.65.235417363https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XltlSkt7k%253D&md5=4e9a26b457d122454b35d680eea99109First-principles calculations of metal stabilized Si20 cagesSun, Q.; Wang, Q.; Briere, T. M.; Kumar, V.; Kawazoe, Y.; Jena, P.Physical Review B: Condensed Matter and Materials Physics (2002), 65 (23), 235417/1-235417/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)It is well known that sp2 bonding in carbon can result in stable cage structures, but pure Si clusters with similar cage structures are unstable. Using first-principles B3LYP-DFT calcns., we show that a dodecahedral cage of silicon can be stabilized dynamically as well as energetically by doping with Ba, Sr, Ca, Zr, and Pb atoms to create structures of silicon similar to that of the smallest carbon fullerene. The stability and bonding in such cages shed light on Si clathrates in which Si20 is the basic building block of the structure. Moreover, the charge distributions and HOMO-LUMO gaps for these cage structures can be tuned by changing the metal atom. This allows addnl. freedom for the design of nanomaterials involving Si.
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364Kawamura, H.; Kumar, V.; Kawazoe, Y. Growth and magic behavior of metal encapsulated silicon clusters. Mater. Trans. 2004, 45, 1429– 1432, DOI: 10.2320/matertrans.45.1429364https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXkvFyjtrs%253D&md5=94682891455ed2b7c0e056a541418243Growth and magic behavior of metal encapsulated silicon clustersKawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiMaterials Transactions (2004), 45 (5), 1429-1432CODEN: MTARCE; ISSN:1345-9678. (Japan Institute of Metals)Metal encapsulated silicon clusters M@Sin (M = Ti and Cr and n = 8-16) were studied using DFT ab-initio ultrasoft pseudopotential method. Several structures for each cluster were optimized to obtain the lowest energy isomers. Cage structures begin to form at size n=12 for Cr@Sin and n=13 for Ti@Sin. For Ti@Sin our results are in excellent agreement with the available exptl. results. For smaller n, metal doped silicon clusters have basket structures which have the lowest energy. The bonding nature in these clusters is discussed from the electronic charge distribution.
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365Kawamura, H.; Kumar, V.; Kawazoe, Y. Growth behavior of metal-doped silicon clusters SinM (M = Ti, Zr, Hf; n = 8–16). Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 075423, DOI: 10.1103/PhysRevB.71.075423365https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXitVKhsLk%253D&md5=c1f29675e411c7545c1cf6b6bf3d3e00Growth behavior of metal-doped silicon clusters SinM (M = Ti,Zr,Hf; n = 8-16)Kawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (7), 075423/1-075423/12CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The growth behavior of metal-doped silicon clusters MSin, M = Ti, Zr, and Hf and n = 8-16 is studied using an ab initio ultrasoft pseudopotential plane wave method and the generalized gradient approxn. for the exchange-correlation energy. For n = 8-12, we find basketlike open structures to be most favorable, while for n = 13-16, the metal atom is completely surrounded by silicon atoms. These results are in excellent agreement with the obsd. reactivity of these clusters. Our results suggest continuous aggregation until n = 16, which is the optimal cage for the metal-encapsulated silicon clusters with these elements. Further calcns. have been done on cation and anion clusters using the Gaussian method. The calcd. electron affinities agree well with exptl. results in the range of n = 12-16 while the calcd. values for smaller clusters are higher. Raman activity and IR spectra have been calcd. for selected clusters. These could help in the identification of the structures of these clusters from expts.
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366Singh, A. K.; Kumar, V.; Kawazoe, Y. Stabilizing the silicon fullerene Si20 by thorium encapsulation. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 115429, DOI: 10.1103/PhysRevB.71.115429366https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXivFehsrc%253D&md5=a4c20bd47a7efadfb22d8c81c0b77eaaStabilizing the silicon fullerene Si20 by thorium encapsulationSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (11), 115429/1-115429/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We show using ab initio electronic structure calcns. that the dodecahedral fullerene of silicon Si20 is stabilized by thorium encapsulation. Thorium is found to be the only element in the Periodic Table that stabilizes this fullerene with icosahedral symmetry in the neutral state. The preference for sp3 bonding in silicon makes it an optimal cage with all pentagonal faces in contrast to carbon for which C20 is difficult to stabilize. Similar to C60, this is the highest symmetry cluster of silicon and should be abundant. It could lead to the possibilities of novel new phases and derivs. of silicon.
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367Kumar, V.; Singh, A. K.; Kawazoe, Y. Charged and magnetic fullerenes of silicon by metal encapsulation: Predictions from ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 125411, DOI: 10.1103/PhysRevB.74.125411367https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVyksrzI&md5=ec4d3ea112031d5caa40fcb5ba362d1fCharged and magnetic fullerenes of silicon by metal encapsulation: Predictions from ab initio calculationsKumar, Vijay; Singh, Abhishek Kumar; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2006), 74 (12), 125411/1-125411/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using ab initio calcns., the encapsulation of Y, La, and Ac metal (M) atom stabilizes the dodecahedral fullerene anion M@Si20- in the icosahedral symmetry. Similar to C60, it is the ideal cage of silicon and the largest that can be stabilized by an M atom. Doping of other rare earths is further shown to stabilize magnetic dodecahedral fullerenes La@Si20, Sm@Si20, Pu@Si20, and Tm@Si20 with 1 μB, 4 μB, 4 μB, and 3 μB spin magnetic moments, resp., in contrast to most previous studies on M-encapsulated Si clusters in which the magnetic moment is completely quenched. The highest spin magnetic moment of 7 μB is achieved for Gd@Si20- with half-filled 4f states. The orbital magnetic moment is also calcd. and it is ∼1 μB in most cases. Neutral M@Si20 (M = Y, La, Ac, and Gd) behaves like superhalogen and interaction with a noble or alkali metal atom leads to salt like behavior. These findings could pave way for the realization of silicon fullerenes by doping of several elements.
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368Hongo, K.; Kumar, V.; Kawazoe, Y.; Yasuhara, H. Quantum monte carlo study of electron correlation in chromium-doped silicon cluster Cr@Si12. Mater. Trans. 2006, 47, 2617– 2619, DOI: 10.2320/matertrans.47.2617368https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntVCisw%253D%253D&md5=777730390d862c621e133efcfdd9de08Quantum monte carlo study of electron correlation in chromium-doped silicon cluster Cr@Si12Hongo, Kenta; Kumar, Vijay; Kawazoe, Yoshiyuki; Yasuhara, HiroshiMaterials Transactions (2006), 47 (11), 2617-2619CODEN: MTARCE; ISSN:1345-9678. (Japan Institute of Metals)Electron correlation in chromium-doped silicon cluster (Cr@Si12) in its neutral, pos., and neg. charged states with different nuclear configurations is investigated by means of quantum Monte Carlo methods. The correlation energy per electron is independent of whether the state is charged or not and about-1 eV for each of these three states. The total binding energy of the neutral state per atom is 3.5 eV, which is divided into the Hartree-Fock contribution nearly equal to 1.2 eV and the correlation contribution as large as 2.3 eV. In the Hartree-Fock approxn., the ionization energy is 6.9 eV and the electron affinity is 2.7 eV. Correlation increases the ionization energy by 1.7 eV and the electron affinity by 1.4 eV.
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369Kumar, V. Alchemy at the nanoscale: Magic heteroatom clusters and assemblies. Comput. Mater. Sci. 2006, 36, 1– 11, DOI: 10.1016/j.commatsci.2005.06.004369https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XislWmsL4%253D&md5=d50b55a67685d83ad35019978600397cAlchemy at the nanoscale: magic heteroatom clusters and assembliesKumar, VijayComputational Materials Science (2006), 36 (1-2), 1-11CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)A review. Mixing of elements at the nanoscale can offer exciting possibilities of novel materials with compns., structures, and properties quite different from those known in bulk. Ab initio calcns. are expected to play a major role in understanding their properties as well as in predicting and designing such materials. Here, we briefly review recent progress where encapsulation of an atom A or a group of atoms G or exohedral atom(s) have been used to stabilize cage-like nanoclusters/fullerenes of material B. The encapsulation enhances the stability of nanoclusters and can lead to striking preference for a specific size. This can facilitate the design and prodn. of nanoclusters with specific properties in high abundances and the development of assemblies of such species. We discuss the electronic origin of the stability of such species as well as assemblies of size selected nanoparticles that have led to the formation of nanowires and nanotubes. Several examples of such clusters of semiconductors and metals are presented.
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370Jaiswal, S.; Babar, V. P.; Kumar, V. Growth behavior, electronic structure, and vibrational properties of SinY anion clusters (n = 4–20): Metal atom as linker and endohedral dopant. Phys. Rev. B: Condens. Matter Mater. Phys. 2013, 88, 085412, DOI: 10.1103/PhysRevB.88.085412370https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsF2kt7vF&md5=e27c6734f0c6ea8870a2cda7337d16f6Growth behavior, electronic structure, and vibrational properties of SinY anion clusters (n = 4-20): metal atom as linker and endohedral dopantJaiswal, S.; Babar, Vasudeo P.; Kumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2013), 88 (8), 085412/1-085412/14CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We report results of ab initio calcns. on Y-doped anion Sin clusters with n = 4-20. Our results suggest two growth behaviors in the intermediate range of n = 8 and 20: (1) There is the formation of linked clusters in which a metal atom links two subclusters and (2) where silicon atoms form a cage structure and the metal atom is inside the cage to produce endohedral cages of silicon clusters. The cluster structures have been identified by comparing the calcd. spectra of the electronic states with the photoemission spectra on anion clusters. Our results suggest that in some cases a higher energy isomer may be present in expts. We report the calcns. of the IR and Raman spectra as well as the dipole moments, electron affinity, and polarizability that could provide other ways of identifying the growth behavior in these clusters.
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371Khanna, S.; Rao, B.; Jena, P. Magic numbers in metallo-inorganic clusters: Chromium encapsulated in silicon cages. Phys. Rev. Lett. 2002, 89, 016803, DOI: 10.1103/PhysRevLett.89.016803371https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XkslCitb4%253D&md5=b884a566eb5ad69cc920df7a672258c1Magic numbers in metallo-inorganic clusters: chromium encapsulated in silicon cagesKhanna, S. N.; Rao, B. K.; Jena, P.Physical Review Letters (2002), 89 (1), 016803/1-016803/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)A systematic DFT-GGA study is presented of the equil. geometries and total energies of Sin and Cr@Sin clusters (n=11-14); Cr@Si12 is more stable than the others. The origin of this enhanced stability is consistent with the 18-electron sum rule commonly used in the synthesis of stable chem. complexes, and may provide a criterion for a systematic search of magic nos. in metallo-inorg. clusters. The 6μB magnetic moment of the caged Cr atom, the largest among the 3d transition metal atoms, is completely quenched. This effect of caging on the properties of transition metal atoms may lead to the synthesis of novel cluster based materials.
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372Xiao, C.; Hagelberg, F.; Lester, W. A., Jr Geometric, energetic, and bonding properties of neutral and charged copper-doped silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 66, 075425, DOI: 10.1103/PhysRevB.66.075425372https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XntVWju7o%253D&md5=974424f95c5f20a22ed29adccabc002aGeometric, energetic, and bonding properties of neutral and charged copper-doped silicon clustersXiao, Chuanyun; Hagelberg, Frank; Lester, William A., Jr.Physical Review B: Condensed Matter and Materials Physics (2002), 66 (7), 075425/1-075425/23CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The authors studied properties of CuSin clusters (n = 4, 6, 8, 10, and 12) in neutral and charged states using the B3LYP-DFT method. The Sin frameworks in most isomers of CuSin adopt the geometries of the ground-state or low-lying isomers of Sin or Sin+1, with Cu at various substitutional or adsorption sites. Several cage-like structures with Cu at the center site were found for CuSi10 and CuSi12. A hexagonal double-chair structure with Cu at the center, which bears a similarity to the structure of a regular hexagonal prism recently reported for WSi12+ [H. Hiura et al., Phys. Rev. Lett. 86, 1733 (2001)], was identified as the best candidate for the ground state of CuSi12. The Cu-Si bond in CuSin is strong for the substitutional and the center-site structures, but weak for the adsorption structures where charge transfer and resulting ionic interaction play a more important role. The Cu atom reveals a similar bonding character to the replaced Si atom in the substitutional structures except for CuSi12, where the Cu atom both in the substitutional and in the center-site structures forms multicenter bonds with as many as nine (substitutional) to 12 (center-site) Si atoms. Various energetic properties, including binding and dissocn. energies, ionization potentials, electron affinities, and vertical detachment energies are reported for CuSin.
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373Han, J.-G.; Xiao, C.; Hagelberg, F. Geometric and electronic structure of WSiN (N = 1–6, 12) clusters. Struct. Chem. 2002, 13, 173– 191, DOI: 10.1023/A:1015712717153373https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XksFCju7c%253D&md5=b5fc18abb0b4a87737ec7df79eb73f20Geometric and Electronic Structure of WSiN(N = 1-6, 12) ClustersHan, Ju-Guang; Xiao, Chuanyun; Hagelberg, FrankStructural Chemistry (2002), 13 (2), 173-191CODEN: STCHES; ISSN:1040-0400. (Kluwer Academic/Plenum Publishers)Geometry optimizations of WSiN (n = 1-6, 12) clusters were performed using the B3LYP/ LanL2DZ method for a sequence of different spin states, changing from spin singlet to spin septet conditions. The resulting equil. structures are discussed in relation to internal charge transfer and magnetic properties. The W impurity in the SiN environment generally acts as an electron acceptor. However, the charge on the W atom, as obtained by natural population anal., can be sensitively tuned through the variation of the spin constraint from S = 0 to S = 3. The resulting geometries of WSin (N = 3-6) are compared with the known ground state structures of SiN+1 (N = 3-6); substitutional geometries are identified for N = 3 and N = 5. The nonzero spin states of WSiN display different patterns of magnetic order, corresponding to uniform and to alternating at. spin orientations within the cluster. Highly compact Oh and D6h structures were identified as stable geometries of WSi6 and of the exptl. detected unit WSi12, resp. Comparison is made with the cluster series MoSiN(N = 1-6) and CuSiN(N = 1-6,12).
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374Miyazaki, T.; Hiura, H.; Kanayama, T. Topology and energetics of metal-encapsulating Si fullerenelike cage clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 66, 121403, DOI: 10.1103/PhysRevB.66.121403374https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvVahtbo%253D&md5=8725646a1420b89d1b71e05070cb6c8eTopology and energetics of metal-encapsulating Si fullerenelike cage clustersMiyazaki, Takehide; Hiura, Hidefumi; Kanayama, ToshihikoPhysical Review B: Condensed Matter and Materials Physics (2002), 66 (12), 121403/1-121403/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)On the basis of a topol. discussion as well as an ab initio calcn., we show that it is possible to construct a fullerenelike Si cage by doping a transition metal atom in the cage center. The cage is a simple 3-polytope which maximizes the no. of its inner diagonals close to the metal atom. Our topol. argument also reveals how closely the structure of the fullerenelike Si cages studied is related to that of fullerenes themselves.
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375Gueorguiev, G.; Pacheco, J. Silicon and metal nanotemplates: Size and species dependence of structural and electronic properties. J. Chem. Phys. 2003, 119, 10313– 10317, DOI: 10.1063/1.1617977375https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXos1Sjtro%253D&md5=9d85abf47879be7a775108db81b0083fSilicon and metal nanotemplates: size and species dependence of structural and electronic propertiesGueorguiev, G. K.; Pacheco, J. M.Journal of Chemical Physics (2003), 119 (19), 10313-10317CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We utilize first-principles computer simulations to study the dependence on size (n) and species (M) of structural and electronic properties of clusters with stoichiometry M Sin. We investigate a total of 168 clusters comprising from 1 to 14 silicon atoms together with one transition metal atom among 12 different elements. It is found that all elements exhibit a very similar size-dependence for the cohesive energy, in which clusters with n=7, 12 appear as local maxima, with shapes which are found to be essentially independent of the transition metal atom. It is also found that the electronic properties of structurally equiv. clusters depend sensitively on the transition metal atom involved, providing the means to tailor specific properties when designing cluster assembled materials.
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376Lu, J.; Nagase, S. Structural and electronic properties of metal-encapsulated silicon clusters in a large size range. Phys. Rev. Lett. 2003, 90, 115506, DOI: 10.1103/PhysRevLett.90.115506376https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXitlelt70%253D&md5=90973920b3456bf4df6bd12580d85295Structural and Electronic Properties of Metal-Encapsulated Silicon Clusters in a Large Size RangeLu, Jing; Nagase, ShigeruPhysical Review Letters (2003), 90 (11), 115506/1-115506/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Structural and electronic properties of metal-doped silicon clusters MSin (M = W, Zr, Os, Pt, Co, etc.) in a large size range of 8 ≤ n≤ 20 are investigated via ab initio calcns. Different from a recent exptl. suggestion that the metal atom is endohedral in MSin, we reveal that the formation of endohedral structure strongly depends on the size of the Sin cluster. Two novel structures of the chem. stable endohedral species are manifested. The suitable M@Sin building blocks of self-assembly materials vary in the range of 10 ≤ n ≤16. The thermodynamical magic nos. are found to coincide with the chem. magic nos. for five clusters.
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377Khanna, S.; Rao, B.; Jena, P.; Nayak, S. Stability and magnetic properties of iron atoms encapsulated in Si clusters. Chem. Phys. Lett. 2003, 373, 433– 438, DOI: 10.1016/S0009-2614(03)00511-6377https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXktFGnur0%253D&md5=6d1cf00e67dd1740fbab4c50a90e6498Stability and magnetic properties of iron atoms encapsulated in Si clustersKhanna, S. N.; Rao, B. K.; Jena, P.; Nayak, S. K.Chemical Physics Letters (2003), 373 (5,6), 433-438CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Equil. geometries, total energies, ionization potentials, electronic structure, and magnetic properties of Fe encapsulated Sin clusters contg. 9-11 Si atoms were calcd. using the d. functional theory and generalized gradient approxn. for exchange and correlation. The geometries of bare Sin clusters are substantially modified due to Fe, which occupies an endohedral position. The Si10Fe cluster is more stable than its neighbors even though not all Si atoms are 4-fold coordinated. The stability of Si10Fe, however, is consistent with the 18-electron rule. The magnetic moment of Fe is quenched in all the clusters studied.
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378Miyazaki, T.; Hiura, H.; Kanayama, T. Electronic properties of transition-metal-atom doped Si cage clusters. Eur. Phys. J. D 2003, 24, 241– 244, DOI: 10.1140/epjd/e2003-00121-x378https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXntFehtrk%253D&md5=15bb1951ad9a70560c7fc3b46fd57204Electronic properties of transition-metal-atom doped Si cage clustersMiyazaki, T.; Hiura, H.; Kanayama, T.European Physical Journal D: Atomic, Molecular and Optical Physics (2003), 24 (1-3), 241-244CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)We present a d.-functional study of electronic structures of convex-caged Si clusters doped with transition-metal (TM) atoms. First, we show the reason for their peculiar geometries in terms of interplay among the electron orbitals of Si and TM atoms. Then we describe the potential ability of the clusters to serve as charge sources to other objects such as Si crystal surfaces.
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379Hagelberg, F.; Xiao, C.; Lester, W. A., Jr Cagelike Si12 clusters with endohedral Cu, Mo, and W metal atom impurities. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 67, 035426, DOI: 10.1103/PhysRevB.67.035426379https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXht1yju78%253D&md5=74d63c4a12c2930016e479e91fb7f710Cagelike Si12 clusters with endohedral Cu, Mo, and W metal atom impuritiesHagelberg, F.; Xiao, C.; Lester, William A.Physical Review B: Condensed Matter and Materials Physics (2003), 67 (3), 035426/1-035426/9CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)In a recent series of mass-spectrometric ion trap measurements [H. Hiura et al., Phys. Rev. Lett. 86, 1733 (2001)], the formation of silicon clusters with endohedral transition-metal impurities was obsd. Particular stability was assigned to the exptl. detected species WSi12+, which has been shown by ab initio geometry optimization to adopt the shape of a regular hexagonal Si12 prism with the W atom in the center. A similar geometry-namely, a Si12 double-chair structure surrounding the metal atom impurity-has emerged from our extensive investigations of silicon clusters in combination with a Cu atom (CuSiN) as the likely ground-state structure of CuSi12. These results suggest the systematic importance of Si12 cages derived from regular structures with D6h geometry for the architecture of silicon clusters contg. metal atom impurities. In the present comparative study, we discuss the salient features of endohedral MSi12 clusters with M = Cu, Mo, W, as well as several cationic and anionic species of these systems, with regard to their geometric and electronic structure. The interaction between the Si12 cage and the enclosed metal impurity is characterized as strongly delocalized bonding for M=Mo, W, while Cu tends to form directed bonds with selected atoms of the cage. Linear extension of the MSi12 (Me=Mo,W) cells along their principal axes leads to units of the form M2Si18.
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380Mpourmpakis, G.; Froudakis, G. E.; Andriotis, A. N.; Menon, M. Fe encapsulation by silicon clusters: Ab initio electronic structure calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 125407, DOI: 10.1103/PhysRevB.68.125407380https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXotVOnur8%253D&md5=66e12a8eda95cd5c7cd212dfb276e7c2Fe encapsulation by silicon clusters: Ab initio electronic structure calculationsMpourmpakis, Giannis; Froudakis, George E.; Andriotis, Antonis N.; Menon, MadhuPhysical Review B: Condensed Matter and Materials Physics (2003), 68 (12), 125407/1-125407/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Ab initio electronic structure calcns. based on d. functional theory are performed for SinFe clusters to det. stable structures. These clusters can form the building block for Fe-encapsulated Si-nanotubes. The Si10Fe and Si12Fe clusters are found to be very stable, exhibiting large charge transfer, and can lead to Si-based nanotubes of the types Si5nFen-1 and Si6nFen-1, resp. The effect of Si encapsulation on the magnetic properties of the Fe atom is also investigated.
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381Sen, P.; Mitas, L. Electronic structure and ground states of transition metals encapsulated in a Si12 hexagonal prism cage. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 155404, DOI: 10.1103/PhysRevB.68.155404381https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVSrtLk%253D&md5=2cab5df5739c4713d903d6923bb1433dElectronic structure and ground states of transition metals encapsulated in a Si12 hexagonal prism cageSen, Prasenjit; Mitas, LubosPhysical Review B: Condensed Matter and Materials Physics (2003), 68 (15), 155404/1-155404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We report on a computational study of the electronic structure of recently discovered clusters with an encapsulated transition metal (TM) atom in a Si12 hexagonal prism cage. The cage geometry is remarkably stable regardless of the type of doping TM atom from 3d, 4d, and 5d series. We predict and quantify the stability for several other TM dopings besides the exptl. obsd. ones. The multiplicity of the ground states can be "tuned" between singlets and triplets by varying the type of TM atom (even no. of electrons), while they are doublets for odd no. of electrons. We also explore the possibility of forming solids with hexagonal structure from selected clusters.
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382Guo, P.; Ren, Z.-Y.; Wang, F.; Bian, J.; Han, J.-G.; Wang, G.-H. Structural and electronic properties of TaSin (n = 1–13) clusters: A relativistic density functional investigation. J. Chem. Phys. 2004, 121, 12265– 12275, DOI: 10.1063/1.1809609382https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFSnsrzM&md5=158dc89c9ce63429813244e6cb4cb7edStructural and electronic properties of TaSin (n=1-13) clusters: A relativistic density functional investigationGuo, Ping; Ren, Zhao-Yu; Wang, Fan; Bian, Jiang; Han, Ju-Guang; Wang, Guang-HouJournal of Chemical Physics (2004), 121 (24), 12265-12275CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The TaSin (n = 1-13) clusters with doublet, quartet, and sextet spin configurations have been systematically investigated by a relativistic d. functional theory with the generalized gradient approxn. available in Amsterdam d. functional program. The total bonding energies, equil. geometries, Mulliken populations as well as Hirshfeld charges of TaSin (n = 1-13) clusters are calcd. and presented. The emphasis on the stabilities and electronic properties is discussed. The most stable structures of the small TaSin (n = 1-6) clusters and the evolutional rule of low-lying geometries of the larger TaSin (n = 7-13) clusters are obtained. Theor. results indicate that the most stable structure of TaSin (n = 1-6) clusters keeps the similar framework as the most stable structure of Sin+1 clusters except for TaSi3 cluster. The Ta atom in the lowest-energy TaSin (n = 1-13) isomers occupies a gradual sinking site, and the site moves from convex, to flatness, and to concave with the no. of Si atom varying from 1 to 13. When n = 12, the Ta atom in TaSi12 cluster completely falls into the center of the Si frame, and a cagelike TaSi12 geometry is formed. Meanwhile, the net Mulliken and Hirsheld populations of the Ta atom in the TaSin (n = 1-13) clusters vary from pos. to neg., manifesting that the charges in TaSin (n ≥ 12) clusters transfer from Si atoms to Ta atom. Addnl., the contribution of Si-Si and Si-Ta interactions to the stability of TaSin clusters is briefly discussed. Furthermore, the investigations on at. averaged binding energies and fragmentation energies show that the TaSin (n = 2,3,5,7,10,11,12) clusters have enhanced stabilities. Compared with pure silicon clusters, a universal narrowing of HOMO-LUMO gap in TaSin clusters is found.
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383Andriotis, A. N.; Mpourmpakis, G.; Froudakis, G. E.; Menon, M. Magnetic enhancement and magnetic reduction in binary clusters of transition metal atoms. J. Chem. Phys. 2004, 120, 11901– 11904, DOI: 10.1063/1.1752878383https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXkvVantrc%253D&md5=fb17bb75316172a94ed0864958b75034Magnetic enhancement and magnetic reduction in binary clusters of transition metal atomsAndriotis, Antonis N.; Mpourmpakis, Giannis; Froudakis, George E.; Menon, MadhuJournal of Chemical Physics (2004), 120 (24), 11901-11904CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Electronic and magnetic properties of small binary clusters contg. one or two transition metal atoms are investigated using ab initio calcns. with a view to explain the exptl. obsd. magnetic enhancement/redn. in these systems. As the present investigations do not rely on spin-orbit effects, our results reveal the enhancement or redn. in the magnetic moment to depend on two main factors; namely geometry and, most importantly, the d-band filling. The results can be used as a guide in the exptl. synthesis of high d. magnetic grains.
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384Han, J.-G.; Ren, Z.-Y.; Lu, B.-Z. Geometries and stabilities of Re-doped Sin (n = 1– 12) clusters: A density functional investigation. J. Phys. Chem. A 2004, 108, 5100– 5110, DOI: 10.1021/jp031006o384https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjvFCnsro%253D&md5=fcbcb4db465ac7674b5559f7e8d4dafcGeometries and Stabilities of Re-Doped Sin (n = 1-12) Clusters: A Density Functional InvestigationHan, Ju-Guang; Ren, Zhao-Yu; Lu, Ben-ZuoJournal of Physical Chemistry A (2004), 108 (23), 5100-5110CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The possible ReSin (n = 1-12) clusters are investigated systematically at the UB3LYP level employing LanL2DZ basis sets for a sequence of different spin states. The total energies and equil. geometries, as well as natural populations and natural electron configurations, are calcd. The emphasis on the stabilities and fragmentation energies as well as on electronic properties is presented and discussed. Theor. results on natural populations reveal that the natural populations of 5d and 6s orbitals of the Re atom in ReSin (n = 1-12) clusters are assocd. with the no. of silicon atoms and spin of this species considered, that the natural population of the Re atom in the most stable ReSin (n = 1-12) clusters is recorded as neg., and that the charges in the most stable ReSin (n = 1-12) transfer from Si atoms and 6s orbitals of the Re atom to 5d orbitals of the Re atom. Therefore, the Re atom, which acts as an acceptor, plays an important role in the stability of ReSin (n = 1-12) clusters. Furthermore, the charge-transfer of ReSin (n = 1-12) depends on the spin of the species considered. Theor. results of equil. geometries on ReSin (n = 1-12) clusters show that the Re atom of the most stable ReSin (n = 1-7) occupies a surface site and absorbs on the surface site of the Si cluster; however, the Re atom of the most stable ReSin (n = 8-12) clusters is trapped in the center site of the Si cluster and directly interacts with all atoms simultaneously with nonequivalent bond lengths; this observation of transition metal (TM) behavior in TM-silicon clusters being favorable to the center site of the silicon frame when n > 7 is in good agreement with exptl. measurement on TbSix- (x = 6-16) clusters. Growth patterns of ReSin (n = 9-12) clusters are discussed showing the sandwichlike structure as the favorable structure. Relative stability is discussed upon removing one silicon atom, showing that ReSi2 and the sandwichlike ReSi12, ReSi11, and ReSi9 clusters have enhanced stability which is regarded as the abundance of the mass spectrometric observation on ReSin+ (n = 1-11). These theor. results are consistent with the at. averaged binding energies also. Comparisons of ReSin (n = 1-12) with available theor. results of MSin (n = 1-6, M = Cr, Mo, W, Ir) cluster series and exptl. measurements are made.
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385Reveles, J. U.; Khanna, S. N. Nearly-free-electron gas in a silicon cage. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 72, 165413, DOI: 10.1103/PhysRevB.72.165413There is no corresponding record for this reference.
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386Wang, J.; Han, J.-G. Geometries, stabilities, and electronic properties of different-sized ZrSin (n = 1–16) clusters: A density-functional investigation. J. Chem. Phys. 2005, 123, 064306, DOI: 10.1063/1.1998887386https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpsVaitrw%253D&md5=a827004253f5ddb21200ee75d13b2ae0Geometries, stabilities, and electronic properties of different-sized ZrSin (n=1-16) clusters: A density-functional investigationWang, Jin; Han, Ju-GuangJournal of Chemical Physics (2005), 123 (6), 064306/1-064306/16CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The ZrSin (n = 1-16) clusters with different spin configurations have been systematically investigated by using the UB3LYP-DFT method. The total energies, equil. geometries, growth-pattern mechanisms, natural population anal., etc., are discussed. The equil. structures of different-sized ZrSin clusters can be detd. by two evolution patterns. The most stable ZrSin (n = 1-7) geometries, except ZrSi3, keep the analogous frameworks as the lowest-energy or the second lowest-energy Sin+1 clusters. However, for large ZrSin (n = 8-16) clusters, Zr atom obviously disturbs the framework of silicon clusters, and the localized position of the transition-metal (TM) Zr atom gradually varies from the surface insertion site to the concave site of the open silicon cage and to the encapsulated site of the sealed silicon cage. The lowest-energy sandwich-like ZrSi12 geometry is not a sealed structure and appears irregular as compared with other TM@Si12 (TM = Re,Ni). The growth patterns of ZrSin (n = 1-16) clusters show Zr-encapsulated structures as favorable geometries. The calcd. fragmentation energies of the ZrSin (n = 1-16) clusters manifest that the magic nos. of stabilities are 6, 8, 10, 14, and 16, and that the fullerenelike ZrSi16 is the most stable structure, which is in good agreement with the calcd. at. binding energies of ZrSin (n = 8-16) and with available exptl. and theor. results. The natural charge population of Zr atom in the most stable ZrSin (n = 1-16) structures varies from pos. to neg. at the crit.-sized ZrSi8 cluster; the charge distribution around the Zr atom appears clearly covalent in character for the small- or middle-sized clusters and metallic in character for the large-sized clusters. The properties of frontier orbitals and polarizabilities of ZrSin are also discussed.
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387Ma, L.; Zhao, J.; Wang, J.; Lu, Q.; Zhu, L.; Wang, G. Structure and electronic properties of cobalt atoms encapsulated in Sin (n = 1–13) clusters. Chem. Phys. Lett. 2005, 411, 279– 284, DOI: 10.1016/j.cplett.2005.06.062387https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXms1OrtL0%253D&md5=6f14ec1617d3d3ea762cbf83b1de4af1Structure and electronic properties of cobalt atoms encapsulated in Sin (n=1-13) clustersMa, Li; Zhao, Jijun; Wang, Jianguang; Lu, Qiliang; Zhu, Lianzhong; Wang, GuanghouChemical Physics Letters (2005), 411 (4-6), 279-284CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)A systematic theor. study of the equil. geometries and energetics of cobalt atoms encapsulated in Sin (n = 1-13) clusters in comparison with pure Sin clusters were done by DFT-GGA method combined with a genetic algorithm. The geometries of bare Sin clusters are substantially modified upon doping with Co atom; Co-doping improves the stability of the clusters for n ≥ 7. In general, the stability of SinCo clusters increases with increasing size n. The Si9Co was found to be magic-no. cluster; the enhanced stability was explained by the 18-electron rule. The magnetic moment on Co atom inside SinCo cluster is quenched in all clusters with n ≥ 4.
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388Guo, P.; Ren, Z.-Y.; Yang, A.-P.; Han, J.-G.; Bian, J.; Wang, G.-H. Relativistic computational investigation: The geometries and electronic properties of TaSin+ (n = 1–13, 16) clusters. J. Phys. Chem. A 2006, 110, 7453– 7460, DOI: 10.1021/jp060130f388https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XkslKhtbg%253D&md5=6814e3be3029aea42df63af5b0a5b1bdRelativistic Computational Investigation: The Geometries and Electronic Properties of TaSin+ (n = 1-13, 16) ClustersGuo, Ping; Ren, Zhao-Yu; Yang, A-Ping; Han, Ju-Guang; Bian, Jiang; Wang, Guang-HouJournal of Physical Chemistry A (2006), 110 (23), 7453-7460CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The equil. geometries, stabilities, and electronic properties of the TaSin+ (n = 1-13, 16) clusters are investigated systematically by using the relativistic d. functional method with generalized gradient approxn. The small-sized TaSin+ clusters with slight geometrical adjustments basically keep the frameworks that are analogous to the neutrals while the medium-sized charged clusters significantly deform the neutral geometries, which are confirmed by the calcd. AIP and VIP values. The optimized geometries of the charged clusters agree with the exptl. results of H. Hiura and co-workers (Phys. Rev. Lett. 2001, 86, 1733). The HOMO-LUMO gaps of the charged clusters are generally increased as the cluster size goes from n = 1 to 13; the large HOMO-LUMO gaps of charged clusters resulting from the pos. charge indicate that their chem. stabilities are stronger than their neutral counterparts, esp. for n = 4, 6, and 7 clusters. The contributions of the d orbitals of the Ta atom to the HOMO and LUMO reveal that the chem. activity of the d orbitals of the Ta atom decreases gradually as the no. of silicon atoms increases. This interesting finding is in good agreement with the recent exptl. results on the reactive activities of the H2O and transition-metal silicon clusters (Koyasu, K.; Akutsu, M.; Mitsui, M.; Nakajima, A. J. Am. Chem. Soc. 2005, 127, 4998). Generally, the pos. charge significantly influences the electronic and geometric structures of the charged clusters. The most stable neutral and charged TaSi16 clusters are found to be fullerene-like structures and the HOMO-LUMO gap in charged form is detectable exptl.
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389Ma, L.; Zhao, J.; Wang, J.; Wang, B.; Lu, Q.; Wang, G. Growth behavior and magnetic properties of SinFe (n = 2–14) clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 73, 125439, DOI: 10.1103/PhysRevB.73.125439389https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjslGqtrc%253D&md5=2260f99f1f879fb8831ad7ba298c8f8eGrowth behavior and magnetic properties of SinFe (n=2-14) clustersMa, Li; Zhao, Jijun; Wang, Jianguang; Wang, Baolin; Lu, Qiliang; Wang, GuanghouPhysical Review B: Condensed Matter and Materials Physics (2006), 73 (12), 125439/1-125439/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The growth behavior and magnetic properties of SinFe (n = 2-14) clusters were studied using the d. functional theory (DFT) within the generalized gradient approxn. (GGA). Extensive search of the lowest-energy structures was conducted by considering a no. of structural isomers for each cluster size. In the ground state structures of SinFe clusters, the equil. site of Fe atom gradually moves from convex, to a surface, and to a concave site as the no. of Si atoms increases from 2 to 14. Starting from n = 10, the Fe atom completely falls into the center of the Si outer frame, forming metal-encapsulated Si cages. Maximum peaks were obsd. for SinFe clusters at n = 5, 7, 10, 12 on the size-dependence of 2nd-order energy difference, implying that these clusters possess relatively higher stability. The electronic structures and magnetic properties of SinFe clusters are discussed. The magnetic moment of the Fe atom in SinFe clusters is quenched around the size of n = 9-10, due to strong hybridization between the 4s and 3d states of Fe and the 3s and 3p states of Si.
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390Uchida, N.; Miyazaki, T.; Kanayama, T. Stabilization mechanism of Si12 cage clusters by encapsulation of a transition-metal atom: A density-functional theory study. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 205427, DOI: 10.1103/PhysRevB.74.205427390https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xhtleju73M&md5=c133a192ca2c1fe0ba83c3abdad03663Stabilization mechanism of Si12 cage clusters by encapsulation of a transition-metal atom: A density-functional theory studyUchida, Noriyuki; Miyazaki, Takehide; Kanayama, ToshihikoPhysical Review B: Condensed Matter and Materials Physics (2006), 74 (20), 205427/1-205427/9CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We systematically studied the geometrical and electronic structures of transition-metal (M) encapsulated in Si12 cage clusters, MSi12 (M = Hf, Ta, W, Re, Os, Ir, Pt, and Au), mainly focusing on their outstanding stability, using the B3PW91 and B3LYP DFT methods. The MSi12 clusters except HfSi12 belong to either of two distinct structural classes, the D6h-sym. hexagonal prism (HP; for M = Ta, W, Re, and Os; total no. of valence electrons per cluster, Nν, ranging from 53 to 56) and less-sym. four pentagonal face (FPF; M = Re, Os, Ir, Pt, and Au; Nν ranging from 55 to 59) structures. The HP structure is particularly stabilized at Nν = 54, which is understood in terms of the electronic shell closure of the M atoms due to the 18-electron rule, and the geometrical symmetry is maintained for Nν = 53, 55, and 56 by the covalent bonding between the M atom and the Si cage accompanied by the cage-to-M charge transfer. The FPF structure is lowest in energy for Nν = 56 and is maintained by the same covalent-bond/charge-transfer mechanism for other values of Nν. We propose that all these results originate from the electronic "rigidness" of the HP and FPF Si cages against the variation of Nν, which is the leading factor governing the stability of MSi12.
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391Reveles, J. U.; Khanna, S. N. Electronic counting rules for the stability of metal-silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 74, 035435, DOI: 10.1103/PhysRevB.74.035435There is no corresponding record for this reference.
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392Chen, Z.; Neukermans, S.; Wang, X.; Janssens, E.; Zhou, Z.; Silverans, R. E.; King, R. B.; Schleyer, P. v. R.; Lievens, P. To achieve stable spherical clusters: General principles and experimental confirmations. J. Am. Chem. Soc. 2006, 128, 12829– 12834, DOI: 10.1021/ja062868g392https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xptlelsbs%253D&md5=d09d1c28a715b5206633a593e9e21385To Achieve Stable Spherical Clusters: General Principles and Experimental ConfirmationsChen, Zhongfang; Neukermans, Sven; Wang, Xin; Janssens, Ewald; Zhou, Zhen; Silverans, Roger E.; King, R. Bruce; Schleyer, Paul von Rague; Lievens, PeterJournal of the American Chemical Society (2006), 128 (39), 12829-12834CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)General principles for designing stable highly sym. clusters are proposed. This approach takes advantage of both the extra stability of cage aromaticity and the good geometrical balance between the outer cage and the endohedral atom. The applicability of these design principles was confirmed by gas-phase exptl. observations on group 14 element cages with endohedral Al's and also is illustrated by many literature examples of diverse systems.
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393Koukaras, E. N.; Garoufalis, C. S.; Zdetsis, A. D. Structure and properties of the Ni@Si12 cluster from all-electron ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2006, 73, 235417, DOI: 10.1103/PhysRevB.73.235417393https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmvFChtL4%253D&md5=432291d75450d05c8541ef41eff8ecd5Structure and properties of the Ni@Si12 cluster from all-electron ab initio calculationsKoukaras, Emmanuel N.; Garoufalis, Christos S.; Zdetsis, Aristides D.Physical Review B: Condensed Matter and Materials Physics (2006), 73 (23), 235417/1-235417/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The structural, electronic, and vibrational properties of the Ni@Si12 cluster have been studied using all-electron ab initio calcns. in the framework of the d. functional theory (DFT) with the hybrid nonlocal exchange and correlation functional of Becke-Lee-Yang-Parr (B3LYP). Perturbation theory was also used for the lowest energy competing structures in order to unambiguously identify the ground state in view of marginal total energy differences at the DFT/B3LYP level of theory. To facilitate possible future exptl. identification and to check the stability of the structures, we have performed vibrational analyses that include Raman and IR spectra for the stable structures. Through the vibrational anal., we have found that the C5v sym. Frank-Kasper structure, based on an icosahedral structural motif, which for some time was believed as the ground state, is unstable. Our calcns. reveal a ground state of "cubic" D2d symmetry, which at the fourth order of perturbation theory is about 1.3 eV lower than the alternative suggested ground state, based on a hexagonal structural motif. This distorted hexagonal structure of CS symmetry at the DFT/B3LYP level of theory is practically isoenergetic to our cubic D2d structure, with a marginal energy difference of about 0.04 eV. In addn. to IR and Raman spectra, we have examd. in detail electronic (bonding and binding), structural, and chem. characteristics that could be important for possible future applications of these or derived from these materials. Such characteristics include total and partial d. of states, crystal orbital overlap populations, binding energies, ionization potentials, electron affinities, "chem. hardness," and embedding energies.
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394Gueorguiev, G. K.; Pacheco, J.; Stafström, S.; Hultman, L. Silicon–metal clusters: Nano-templates for cluster assembled materials. Thin Solid Films 2006, 515, 1192– 1196, DOI: 10.1016/j.tsf.2006.07.114394https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtFKktLbK&md5=2020596c93d107b5cf568c1a35ffcf70Silicon-metal clusters: Nano-templates for cluster assembled materialsGueorguiev, G. K.; Pacheco, J. M.; Stafstroem, S.; Hultman, L.Thin Solid Films (2006), 515 (3), 1192-1196CODEN: THSFAP; ISSN:0040-6090. (Elsevier B.V.)The structure, cohesive energy and electronic properties of MSin clusters were studied by 1st-principles calcns. as a function of size (n) and (M). The authors studied 168 different clusters, contg. from 1 to 14 Si atoms together with one transition metal atom among 12 different elements: Ti, Zr, Hf, V, Nb, Ta, Ni, Pd, Pt, Cu, Ag, Au. Clusters with n = 7, 10, 12 appear as local maxima in cohesive energy, independently of the metal involved. This, together with previous findings for MSin (contg. 12 other transition metal elements), establishes a systematic behavior. For most metals, MSi12 and MSi10 (the smallest endohedral species) are highly sym. and exhibit local (with respect to their neighbors in size) stability. Thus, besides practically all MSi12 clusters (exceptions being HfSi12, ZrSi12), also some MSi10 such as VSi10, NiSi10, PdSi10, NbSi10 and AgSi10, are promising candidates as building blocks for cluster assembled materials. Electronic properties of structurally equiv. clusters depend markedly on the transition metal involved, providing the means to tailor pre-defined properties when designing extended phases.
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395Kumar, V. Novel metal-encapsulated caged clusters of silicon and germanium. Eur. Phys. J. D 2003, 24, 227– 232, DOI: 10.1140/epjd/e2003-00194-5395https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXntFehtro%253D&md5=edde3d7a8d4122f999b47cab625273b2Novel metal-encapsulated caged clusters of silicon and germaniumKumar, V.European Physical Journal D: Atomic, Molecular and Optical Physics (2003), 24 (1-3), 227-232CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)A review. We report the recent findings of metal (M) encapsulated clusters of silicon from computer expts. based on ab initio total energy calcns. and a cage shrinkage and atom removal approach. Our results show that using a guest atom, it is possible to wrap silicon in fullerenelike (f) structures, as sp2 bonding is not favorable to produce empty cages unlike for carbon. Transition M atoms have a strong bonding with the silicon cage that are responsible for the compact structures. The size and structure of the cage change from 14 to 20 Si atoms depending upon the size and valence of the M atom. Fewer Si atoms lead to relatively open structures. We find cubic, f, Frank-Kasper (FK) polyheral type, decahedral, icosahedral and hexagonal structures for M@Sin with n = 12-16 and several different M atoms. The magic behavior of 15 and 16 atom Si cages is in agreement with expts. The FK polyhedral cluster, M@Si16 has an exceptionally large d. functional gap of about 2.35 eV calcd. within the generalized gradient approxn. It is likely to give rise to visible luminescence in these clusters. The cluster-cluster interaction is weak that makes such clusters attractive for cluster assembled materials. Further studies to stabilize Si20 cage with M = Zr, Ba, Sr, and Pb show that in all cases there is a distortion of the f cage. Similar studies on M encapsulated germanium clusters show FK polyhedral and decahedral isomers to be more favorable. Also perfect icosahedral M@Ge12 and M@Sn12 clusters have been obtained with large gaps by doping with divalent M atoms. Recent results of the H interaction with these clusters, hydrogenated silicon fullerenes as well as assemblies of clusters such as nanowires and nanotubes are briefly presented.
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396Zorriasatein, S.; Joshi, K.; Kanhere, D. Dopant-induced stabilization of silicon clusters at finite temperature. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 045117, DOI: 10.1103/PhysRevB.75.045117396https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhs1ertLY%253D&md5=c3c7e6c98f489f811b2965f2cb558affDopant-induced stabilization of silicon clusters at finite temperatureZorriasatein, Shahab; Joshi, Kavita; Kanhere, D. G.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (4), 045117/1-045117/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)With the recent advances in miniaturization, understanding and controlling the properties of technol. significant materials such as Si in the nano regime assumes considerable importance. The Si clusters in the size range of 15-20 atoms are known to be unstable upon heating. For example, Si20 does not melt but fragments around 1250 K, whereas Si15 has a liq.-like phase spread over a short temp. range and undergoes fragmentation at approx. 1800 K. It is possible to suppress such a fragmentation process by introducing the appropriate dopant (in this case Ti). Specifically, by using the first-principles d. functional simulations we show that Ti-doped Si16, having the Frank-Kasper polyhedral, remains stable till at least 2200 K and fragments only above 2600 K. The obsd. melting transition is a 2-step process. The first step is initiated by the surface melting at approx. 600 K. In the second step, the destruction of the cage takes place at approx. 2250 K, giving rise to a peak in the heat capacity curve.
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397Zdetsis, A. D. Bonding and structural characteristics of Zn-, Cu-, and Ni-encapsulated Si clusters: Density-functional theory calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 085409, DOI: 10.1103/PhysRevB.75.085409397https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXislartb4%253D&md5=ac42491205e62fd78060d4915249ee0cBonding and structural characteristics of Zn-, Cu-, and Ni-encapsulated Si clusters: Density-functional theory calculationsZdetsis, Aristides D.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (8), 085409/1-085409/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The bonding and structural characteristics of metal (M) embedded silicon clusters M@Si12 and M@Si10, M=Zn,Cu,Ni have been studied in parallel within the framework of the d. functional theory with the hybrid nonlocal exchange and correlation functional of Becke and Lee, Yang and Parr (B3LYP). It is illustrated that for Zn and Cu, which are characterized by filled d shells the bonding and structure are largely characterized by the valence metal electrons, contrary to Ni and other transition metals where the bonding is dominated by the filling of the empty d shells by cage electrons. In M@S|i12 clusters there is a strong competition between cubic, icosahedral, and hexagonal prismatic structures. However, with the possible exception of Zn@Si12, the corresponding fully sym. Oh, Ih, and D6h structures for all three metals are statically and/or dynamically unstable due to Jahn-Teller distortions. In addn. to M@Si12, hydrogenated M@Si12H12, M=Ni,Zn clusters have been studied in order to examine the changes in the bonding and structural properties induced by satg. the dangling bonds with surface-hydrogen. In these clusters the effect of hydrogen consists in weakening considerable (up to zero) the metal-cage interactions, enhancing the sp3 cage interactions. This leads in many cases to empty hydrogenated silicon cages, after the removal of the metal atom, which are very stable and sym. with large highest occupied-LUMO (HOMO-LUMO) energy and optical gaps.
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398Wang, J.; Ma, Q.-M.; Xie, Z.; Liu, Y.; Li, Y.-C. From SinNi to Ni@Sin: An investigation of configurations and electronic structure. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 76, 035406, DOI: 10.1103/PhysRevB.76.035406398https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXos1ars7Y%253D&md5=97c6f1566b17b6e715e5be88b6bc95e6From SinNi to Ni@Sin: An investigation of configurations and electronic structureWang, Jing; Ma, Qing-Min; Xie, Zun; Liu, Ying; Li, You-ChengPhysical Review B: Condensed Matter and Materials Physics (2007), 76 (3), 035406/1-035406/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The configurations and electronic structure of SinNi (n = 1 - 14) clusters have been calcd. in the framework of all-electron d.-functional theory. The calcd. results reveal that the Ni atom prefers to occupy the surface site when n < 9 and for the clusters with n ≥ 9, the Ni atom starts to encapsulate in the cage. Furthermore, in the size dependence of embedding energy, max. peak is obsd. for SinNi clusters at n = 12, implying that the Si12Ni cluster is the most stable structure. The doped Ni atom enhances the stability of silicon clusters and helps to form the Ni-encapsulated Si cage. Consequently, all the calcd. results provide a further understanding of structural transformation and relative stabilities of metal-encapsulated Si cages.
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399Wang, J.; Zhao, J.; Ma, L.; Wang, B.; Wang, G. Structure and magnetic properties of cobalt doped Sin (n = 2–14) clusters. Phys. Lett. A 2007, 367, 335– 344, DOI: 10.1016/j.physleta.2007.01.093399https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXnvFyktL8%253D&md5=0738e9c36c1dd4d8ffdf4b4076928759Structure and magnetic properties of cobalt doped Si n (n = 2 - 14) clustersWang, Jianguang; Zhao, Jijun; Ma, Li; Wang, Baolin; Wang, GuanghouPhysics Letters A (2007), 367 (4-5), 335-344CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The structure and magnetic properties of Co-doped Sin (n = 2 - 14) clusters were systematically studied using d. functional theory (DFT). For each cluster size, extensive search of the lowest-energy structure was conducted by considering a no. of structural isomers. The equil. site of the Co atom in the ground-state structures of SinCo clusters gradually moves from convex, surface, to interior sites as the no. of Si atom increases from 2-14. Starting from Si10Co, Co atom is fully encapsulated by the Si outer cages. The magnetic moment of Co atom in SinCo clusters is completely quenched at n = 7 , due to charge transfer and strong hybridization between 4s and 3d states of Co and 3s and 3p states of Si.
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400Torres, M.; Balbás, L. Relative stability of Sin and SinSc- clusters in the range n = 14–18). Eur. Phys. J. D 2007, 43, 217– 220, DOI: 10.1140/epjd/e2007-00086-8400https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXls1KhtLc%253D&md5=f4ccacc33758d84fbcb3b06b2ede3427Relative stability of Sin and SinSc- clusters in the range n = 14-18Torres, M. B.; Balbas, L. C.European Physical Journal D: Atomic, Molecular, Optical and Plasma Physics (2007), 43 (1-3), 217-220CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)We present a first-principles DFT-GGA pseudopotential optimization of the lower energy equil. structure of SinSc- anions for n = 14-18. We find that Si16Sc- is more stable than its neighbors clusters, in agreement with recent exptl. mass spectra. We also optimize the geometry of pure Sin neutral clusters in the range n = 14-18, and compare our results with those from previous first-principles calcns.
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401Torres, M.; Fernández, E.; Balbás, L. Theoretical study of isoelectronic SinM clusters (M = Sc–, Ti, V+; n = 14–18. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 205425, DOI: 10.1103/PhysRevB.75.205425401https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntV2ntbY%253D&md5=4708604e2782535d0be343778d321788Theoretical study of isoelectronic SinM clusters (M = Sc-, Ti, V+; n = 14-18)Torres, M. B.; Fernandez, E. M.; Balbas, L. C.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (20), 205425/1-205425/12CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We study, from first-principles quantum mech. calcns., the structural and electronic properties of several low-lying energy equil. structures of isoelectronic SinM clusters (M = Sc-, Ti, V+) for n = 14-18. The main result is that those clusters with n = 16 are more stable than its neighbors, in agreement with recent exptl. mass spectra. By analyzing the orbital charge distribution and the partial orbital d. of states, that special stability is rationalized as a combination of geometrical (near spherical cagelike structure for n = 16) and electronic effects (l-selection rule of the spherical potential model). The structures of the two lowest energy isomers of Si16M are nearly degenerate, and consist of the Frank-Kasper polyhedron and a distortion of that polyhedron. The first structure is the ground state for M = V+, and the second is the ground state for Ti and Sc-. For the lowest energy isomers of clusters SinM with n = 14-18, we analyze the changes with size n, and impurity M of several quantities: binding energy, second difference of total energy, HOMO-LUMO gap, adiabatic electron affinity, addn. energy of a Si atom, and addn. energy of an M impurity to a pure Sin cluster. We obtain good agreement with available measured adiabatic electron affinities for SinTi.
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402Han, J.-G.; Zhao, R.-N.; Duan, Y. Geometries, stabilities, and growth patterns of the bimetal Mo2-doped Sin (n = 9–16) clusters: A density functional investigation. J. Phys. Chem. A 2007, 111, 2148– 2155, DOI: 10.1021/jp0661903402https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhvF2ru7Y%253D&md5=ffc0df94c129de887fc3933dfc549302Geometries, Stabilities, and Growth Patterns of the Bimetal Mo2-doped Sin (n = 9-16) Clusters: A Density Functional InvestigationHan, Ju-Guang; Zhao, Run-Ning; Duan, YuhuaJournal of Physical Chemistry A (2007), 111 (11), 2148-2155CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The authors studied bimetal Mo-Mo doped cage-like silicon clusters Mo2Sin using the DFT-B3LYP method. The growth-pattern, relative stabilities, and charge-transfer in these clusters are presented and discussed. The optimized geometries reveal that the dominant growth patterns of the bimetal Mo-Mo doped on opened cage-like silicon clusters (n = 9-13) are based on pentagon prism MoSi10 and hexagonal prism MoSi12; the Mo2 encapsulated Sin(n = 14-16) frames are dominant in the growth of larger clusters. The Mo2 dimer in the Sin frames is dissocd. due to interaction with the Sin frames. The calcd. fragmentation energies show that the stable clusters are Mo2-doped Si10 and Si12 clusters; the Mo2-doped Si10 is the most stable cluster. Natural population anal. shows that the charge-transfer in Mo2-doped Sin clusters is analogous to the charge transfer in Sin doped with Re or W single atoms. The frontier orbitals of Mo2-doped Sin (n = 10 and 12) clusters show that the Mo2Si10 and Mo2Si12 isomers have enhanced chem. stabilities due to larger HOMO-LUMO gaps. The geometry of the most stable Mo2Si9 cluster has the framework which is analogous to that of Ni2Ge9 cluster confirmed by recent exptl. observation (Goicoechea, J. M.; Sevov, S. C. J. Am Chem. Soc. 2006, 128, 4155).
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403Guo, L.-J.; Liu, X.; Zhao, G.-F.; Luo, Y.-H. Computational investigation of TiSin (n = 2–15) clusters by the density-functional theory. J. Chem. Phys. 2007, 126, 234704, DOI: 10.1063/1.2743412403https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntF2iuro%253D&md5=b601b683920b3b5eab62db0f139abfaaComputational investigation of TiSin (n = 2-15) clusters by the density-functional theoryGuo, Ling-Ju; Liu, Xia; Zhao, Gao-Feng; Luo, You-HuaJournal of Chemical Physics (2007), 126 (23), 234704/1-234704/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometries, stabilities, and electronic properties of TiSin (n = 2-15) clusters with different spin configurations were systematically investigated by using d.-functional theory approach at B3LYP/LanL2DZ level. The equil. site of Ti atom gradually moves from convex to surface, and to a concave site as the no. of Si atom increases from 2 to 15. The Ti atom in TiSi12 completely falls into the center of the Si outer frame, forming metal-encapsulated Si cages, which can be explained by using 16-electron rule. On the basis of the optimized geometries, various energetic properties were calcd. for the most stable isomers of TiSin clusters, including the av. binding energy, the HOMO and LUMO (HOMO-LUMO) gap, fragmentation energy, and the second-order difference of energy. For n = 6,8,12 the clusters are more stable than neighboring ones. According to the Mulliken charge population anal., charges always transfer from Si atoms to Ti atom. Furthermore, the HOMO-LUMO gaps of the most stable TiSin clusters are usually smaller than those of Sin clusters.
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404Chuang, F.-C.; Hsieh, Y.-Y.; Hsu, C.-C.; Albao, M. A. Geometries and stabilities of Ag-doped Sin (n = 1–13) clusters: A first-principles study. J. Chem. Phys. 2007, 127, 144313, DOI: 10.1063/1.2775447404https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtF2msbvM&md5=4f10917a6a6b5012a1279b3d0cd4590cGeometries and stabilities of Ag-doped Sin (n = 1-13) clusters: A first-principles studyChuang, Feng-Chuan; Hsieh, Yun-Yi; Hsu, Chih-Chiang; Albao, Marvin A.Journal of Chemical Physics (2007), 127 (14), 144313/1-144313/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures of AgSin (n = 1-13) clusters are investigated using first-principles calcns. Our studies suggest that AgSin clusters with n = 7 and 10 are relatively stable isomers and that these clusters prefer to be exohedral rather than endohedral. Moreover, doping leaves the inner core structure of the clusters largely intact. Addnl., the plot of fragmentation energies as a function of silicon atoms shows that the AgSin are favored to dissoc. into one Ag atom and Sin clusters. Alternative pathways exist for n > 7 (except n = 11) in which the Ag-Si cluster dissocs. into a stable Si7 and a smaller fragment AgSin-7. The AgSi11 cluster dissocs. into a stable Si10 and a small fragment AgSi. Lastly, our anal. indicates that doping of Ag atom significantly decreases the gaps between the HOMO and the LUMO for n > 7.
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405Guo, L.-j.; Zhao, G.-f.; Gu, Y.-z.; Liu, X.; Zeng, Z. Density-functional investigation of metal-silicon cage clusters MSin (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn; n = 8–16). Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 195417, DOI: 10.1103/PhysRevB.77.195417405https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmslOgsrs%253D&md5=dd975f43d31614b1b1b3ebb3c7d38277Density-functional investigation of metal-silicon cage clusters MSin (M=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn; n=8-16)Guo, Ling-ju; Zhao, Gao-feng; Gu, Yu-zong; Liu, Xia; Zeng, ZhiPhysical Review B: Condensed Matter and Materials Physics (2008), 77 (19), 195417/1-195417/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The geometries, stabilities, electronic, and magnetic properties of the transition metal encapsulated MSin (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn; n = 8-16) clusters have been systematically investigated by using d. functional theory with generalized gradient approxn. It is shown that every transition metal atom (TMA) will fall into the center of Si outer frame and form a metal-encapsulated Si cage at a certain size (ScSi14, TiSi12, VSi12, CrSi12, MnSi11, FeSi10, CoSi10, NiSi10 CuSi12, and ZnSi14). The size of the smallest cagelike structures cannot be detd. by the radius of the TMA alone; the bonding properties and the orbital hybridization between TMA and Si atoms also play an important role. The stability of the cagelike MSin clusters cannot be understood by electron shell filling (18 or 20 electrons) rule; it depends on other factors. The total magnetic moments of MSin clusters and the magnetic moments of TMA in MSin clusters are not always quenched when the TMA falls into the center of the Si outer frame.
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406Hossain, D.; Pittman, C. U., Jr; Gwaltney, S. R. Structures and stabilities of copper encapsulated within silicon nano-clusters: Cu@Sin (n = 9–15). Chem. Phys. Lett. 2008, 451, 93– 97, DOI: 10.1016/j.cplett.2007.11.067406https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXit1ansQ%253D%253D&md5=84c98e5c171665a04fb51da9caa91c52Structures and stabilities of copper encapsulated within silicon nano-clusters: Cu@Sin (n =9-15)Hossain, Delwar; Pittman, Charles U.; Gwaltney, Steven R.Chemical Physics Letters (2007), 451 (1-3), 93-97CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)D. functional electronic-structure calcns. were performed for Cu@Sin (n = 9-15) clusters. The lowest-energy endohedral structure and its stability for each Cu@in cluster were detd. The encapsulation of Cu within silicon clusters generates stable neutral Cu@in clusters. The binding energies and embedding energies of these clusters indicate that they are likely to be chem. stable. The relative cluster stabilities and other thermodn. properties alternate with cluster size, with an apparent preference existing for clusters with an even no. of Si atoms.
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407Yang, A.-P.; Ren, Z.-Y.; Guo, P.; Wang, G.-H. Geometries, stabilities, and electronic properties of Y-doped Sin (n = 1–16) clusters: A relativistic density functional investigation. J. Mol. Struct.: THEOCHEM 2008, 856, 88– 95, DOI: 10.1016/j.theochem.2008.01.016407https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXkvVGrt78%253D&md5=a8956206625747c06bed75ccb6884e23Geometries, stabilities, and electronic properties of Y-doped Sin (n =1-16) clusters: A relativistic density functional investigationYang, A.-Ping; Ren, Zhao-Yu; Guo, Ping; Wang, Guang-HouJournal of Molecular Structure: THEOCHEM (2008), 856 (1-3), 88-95CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)The geometries, stabilities, and electronic properties of YSin (n = 1-16) clusters are investigated systematically via a relativistic d. functional theory with the generalized gradient approxn. For n = 1-14, the most stable YSin geometries generally are analogous to the low-lying Sin+1 clusters; in the size range n = 11-14, they are prolate in shape and form sandwich structures with Y atom occupying a surface site. When the cluster size goes up to 15, the Y atom abruptly drops into the silicon cage, together with the alteration in the direction of charge transfer revealed by the Hirshfeld charge anal. The calcd. at. averaged binding energies and fragmentation energies manifest that the YSin (n = 2, 5, 8, 11, and 14) clusters have remarkably enhanced stabilities. Moreover, the HOMO-LUMO gaps of YSin clusters are universally narrow, compared with those of pure silicon clusters. The calcd. HOMO and LUMO energies for Y-encapsulated YSin (n = 15, 16) are evidently lower than those of the small-sized YSin (n = 1-14) clusters.
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408Peng, Q.; Shen, J. Growth behavior of La@Sin (n = 1–21) metal-encapsulated clusters. J. Chem. Phys. 2008, 128, 084711, DOI: 10.1063/1.2834691408https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtVGqu78%253D&md5=6119a4aa2b48bd9cbe5bd9af05b12b3dGrowth behavior of La@Sin (n = 1-21) metal-encapsulated clustersPeng, Qi; Shen, JiangJournal of Chemical Physics (2008), 128 (8), 084711/1-084711/11CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)D. functional theory involving generalized gradient approxn. correlation functional is used to investigate the cluster series La@Sin (n = 1-21). We find that the growth process of La@Sin (n = 1-21) could be divided into three stages: First, La atom adheres to other Si atoms in the size range of 1 ≤ n ≤ 10; then, La atom is surrounded by Si atoms with basketlike structures in the size range of 11 ≤ n ≤ 15; finally, La atom is completely encapsulated into the fullerene cage structures in the size range of 16 ≤ n ≤ 21. The growth of fullerene cage starts from La@Si16 and stops at La@Si20. By studying La@Sin+ cations and La@Sin- anions, we find that the La atom charge curves of neutral clusters, cations, and anions have a cross point at La@Si12. Adiabatic ionization potential and electron affinity are studied too. Lastly, based on the ground state geometries of La@Sin clusters, we simulate the chem. reaction in which La@SinH2n+ cation has been produced and explain why Hiura et al. only obsd. La@SinH2n+ (n = 1-4) cations in their expt. (c) 2008 American Institute of Physics.
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409Wang, J.; Liu, J. H. Investigation of size-selective Zr2@Sin (n = 16–24) caged clusters. J. Phys. Chem. A 2008, 112, 4562– 4567, DOI: 10.1021/jp801828b409https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXltVyjsb8%253D&md5=c2223110b8b027e21e394d5f1bd6bca2Investigation of Size-Selective Zr2@Sin (n = 16-24) Caged ClustersWang, Jin; Liu, Jin HuaiJournal of Physical Chemistry A (2008), 112 (20), 4562-4567CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The size-selective Zr2Sin (n = 16-24) caged clusters were investigated by DFT methods. Their geometries, relative stabilities, electronic properties and ionization potentials are been discussed. The dominant structures of bimetallic Zr2 doped silicon caged clusters gradually transform to Zr2 totally encapsulated structures with increase of the cluster size from 16 to 24, which is good agreement with the recent exptl. result (J. Phys. Chem. A. 2007, 111, 42). Two novel isomers, i.e., naphthalene-like and dodecahedral Zr2Si20 clusters, were found. Novel quasi-1D naphthalene-like ZrnSim nanotubes are reported. The second-order energy differences reveal that magic nos. of the different sized neutral Zr2Sin clusters appear at n = 18, 20 and 22, which are attributed to the fullerene-like, dodecahedral and polyhedral structures, resp. The HOMO-LUMO gaps ( > 1 eV) of all the size-selective Zr2Sin clusters suggest that encapsulation of the bimetallic zirconium atoms is favorable for increasing the stabilities of silicon cages.
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410Bandyopadhyay, D. A density functional theory–based study of the electronic structures and properties of cage like metal doped silicon clusters. J. Appl. Phys. 2008, 104, 084308, DOI: 10.1063/1.3000657410https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlWks7vL&md5=db035739c73279180debd5d8759cb340A density functional theory-based study of the electronic structures and properties of cage like metal doped silicon clustersBandyopadhyay, DebashisJournal of Applied Physics (2008), 104 (8), 084308/1-084308/7CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Ab initio electronic-structure calcns. were performed by using d. functional theory with polarized basis set (LanL2DZ) within the spin polarized generalized gradient approxn. for metal (M = Ti,Zr,Hf) doped Sin clusters where n varies from 9 to 20. In the first step of the calcn., geometrical optimizations of the nanoclusters have been done. In the next step, these optimized geometries have been used to calc. the binding energy (BE) and HOMO-LUMO gap (ΔEg) of the clusters. In order to check the stability of the clusters, the second order energy differences of the optimized geometries have been calcd. To study the optical behavior of the clusters, IR and Raman spectra calcn. have been done. Further calcns. on cation and anion clusters have been done to obtain their ionization potential (IP), electron affinity (EA), and chem. potential. (c) 2008 American Institute of Physics.
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411Bandyopadhyay, D.; Kumar, M. The electronic structures and properties of transition metal-doped silicon nanoclusters: A density functional investigation. Chem. Phys. 2008, 353, 170– 176, DOI: 10.1016/j.chemphys.2008.08.017411https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht12jurbN&md5=f7f592b0698ec6a1ccd40c426a07954fThe electronic structures and properties of transition metal-doped silicon nanoclusters: A density functional investigationBandyopadhyay, Debashis; Kumar, ManishChemical Physics (2008), 353 (1-3), 170-176CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)We report an ab initio all electron mol.-orbital electronic-structure calcn. by using d. functional theory (DFT) and with polarized basis set (LanL2DZ) within the spin polarized generalized gradient approxn. for metal-doped silicon clusters, SinM (n = 14-20 and M = Ti, Zr, Hf). As the first step of calcn., geometrical optimizations of the nanoclusters were done. These optimized geometries were used to calc. the binding energy and HOMO-LUMO gap (band gap) of the clusters. In order to check the dynamical stability of the clusters, IR and Raman spectra were calcd. Further calcns. were done on cation and anion clusters to obtain ionization potential (IP), electron affinity (EA), chem. potential and chem. hardness of the optimized clusters.
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412Bandyopadhyay, D. The study of the electronic structures and properties of pure and transition metal-doped silicon nanoclusters: A density functional theory approach. Mol. Simul. 2009, 35, 381– 394, DOI: 10.1080/08927020802603598412https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjsFensL0%253D&md5=54e41f1e02dbeeb1d35fffb961362361The study of the electronic structures and properties of pure and transition metal-doped silicon nanoclusters: a density functional theory approachBandyopadhyay, DebashisMolecular Simulation (2009), 35 (5), 381-394CODEN: MOSIEA; ISSN:0892-7022. (Taylor & Francis Ltd.)This report presents the study of ab initio electronic structure and properties of pure and transition metal (TM = Ti, Zr and Hf)-doped silicon clusters, TM@i(n), by using d. functional theory with a polarized basis set (LanL2DZ) within the spin-polarised generalized gradient approxn. for different values of n varying from 8 to 20. As the first step of the study, different optimized geometries of pure and doped clusters are calcd. These optimized clusters are then used to calc. different structural and phys. parameters of the clusters, like binding energy, HOMO - LUMO (HOMO-LUMO) gap, charge transfer, etc. In order to check the stability of the clusters, the second-order difference in the energy of the optimized structures is calcd. To study the optical behavior of the clusters, IR and Raman spectra are also calcd. Further calcns. are also done on cation and anion clusters of both pure and doped nanoclusters to obtain their ionization potential, electron affinity and chem. potential. An effort has been made to correlate the variation of different calcd. parameters with the size of the clusters to explain the real existence and stabilities of different TM-doped clusters.
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413Zhao, G.-f.; Sun, J.-m.; Gu, Y.-z.; Wang, Y.-x. Density-functional study of structural, electronic, and magnetic properties of the EuSin (n = 1–13) clusters. J. Chem. Phys. 2009, 131, 114312, DOI: 10.1063/1.3232009413https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFGrsb%252FL&md5=0b33b799fe4a76e0d579b4c874c5af56Density-functional study of structural, electronic, and magnetic properties of the EuSin (n = 1-13) clustersZhao, Gao-feng; Sun, Jian-min; Gu, Yu-zong; Wang, Yuan-xuJournal of Chemical Physics (2009), 131 (11), 114312/1-114312/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometries, stabilities, and electronic and magnetic properties of europium encapsulated EuSin (n = 1-13) clusters were studied systematically by using relativistic d. functional theory with generalized gradient approxn. Starting from n = 12, the Eu atom completely falls into the center of the Si frame, i.e., EuSi12 is the smallest fully endohedral Eu silicon cluster. The interesting finding is in good agreement with the recent exptl. results on the photoelectron spectroscopy of the europium silicon clusters. The magnetic moments of the EuSin (n = 1-13) clusters are also studied, and the total magnetic moments of the EuSin clusters and the magnetic moments on Eu do not quench when the Eu is encapsulated in the Si outer frame cage. Most of the 4f electrons of the Eu atom in the EuSi12 cluster do not interact with the silicon cage and the total magnetic moments are overwhelming majority contributed by the 4f electrons of the Eu atom. According to the binding energy per atom, the 2nd difference in energy (Δ2E), and vertical ionization potential, the EuSin (n = 4, 9, 12) clusters are very stable. (c) 2009 American Institute of Physics.
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414Lan, Y.-Z.; Feng, Y.-L. Comparative study on the geometric and energetic properties, absorption spectra, and polarizabilities of charged and neutral Cu@Sin clusters (n = 9–14). Phys. Rev. A: At., Mol., Opt. Phys. 2009, 79, 033201, DOI: 10.1103/PhysRevA.79.033201414https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXktVymsr0%253D&md5=7c72e240f68503d3efa5da5f51a2fe37Comparative study on the geometric and energetic properties, absorption spectra, and polarizabilities of charged and neutral Cu @ Sin clusters (n=9-14)Lan, You-Zhao; Feng, Yun-LongPhysical Review A: Atomic, Molecular, and Optical Physics (2009), 79 (3, Pt. B), 033201/1-033201/9CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)The comparative study on the geometric and energetic properties, absorption spectra, and polarizabilities of cagelike CuSin clusters (n = 9-14; indicated by Cu @ Sin) was performed using the d.-functional theory. The influence of a charge on these properties was studied. The charge has more effect on the geometry of Cu @ Sin (n = 9, 11, and 13) than Cu @ Sin (n = 10, 12, and 14). For n = 10-13, the charge directly leads the neutral geometry to the transition state geometry with 1 imaginary frequency. The influence of a charge on the overall and relative stabilities of the neutral and charged Cu @ Sin clusters was analyzed based on the binding energy, energy gap, adiabatic electron affinity, adiabatic ionization potential, and 2nd-order energy difference. The charge slightly increases the binding energy by ∼0.13 eV. For the charged clusters, those with n = 10, 12, and 14 still have a higher relative stability than those with n = 9, 11, and 13. In the visible range, the shape of the absorption spectra is not influenced by a charge. However, the charge results in a blueshift of the absorption spectra. The order of anion°neutral°cation for the static isotropic polarizabilities does not apply to the dynamic isotropic polarizabilities at some optical-field frequencies due to the 1-photon resonance, which is based on the absorption spectra and the sum-over-states formula of the polarizabilities. The charge significantly affects the static anisotropic polarizabilities because the charge influences the geometry of the clusters. The charge also influences the resonant behavior of the dynamic polarizabilities due to its effect on the absorption spectra.
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415Wang, J.; Liu, J. H. Novel bi-transition metallic encapsulated naphthalene-like Si20 prismatic cage: A DFT investigation. J. Comput. Chem. 2009, 30, 1103– 1110, DOI: 10.1002/jcc.21137415https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXltFSlsrc%253D&md5=f3718b2e7676852af248c180c25b72f2Novel bi-transition metallic encapsulated naphthalene-like Si20 prismatic cage: a DFT investigationWang, Jin; Liu, Jin HuaiJournal of Computational Chemistry (2009), 30 (7), 1103-1110CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)A theor. investigation of stabilities and electronic properties of novel transition bimetallic atoms (BTMAs) encapsulated naphthalene-like Si20 prismatic cage is being reported for the first time. The symmetry and electronic state of naphthalene-like TMA2@Si20 is significantly affected by the type of encapsulated TMA from 3d, 4d to 5d series. Because of high binding energies, relative high HOMO-LUMO gaps, large charge-reverse transferring from naphthalene-like Si20 cage to BTMAs at the center of the 5d series, the most stable species of TMA2@Si20 cage is favorable to form new 1D-TMAn@Sim nanotube, which is based on array of the novel naphthalene-like structure.
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416Li, J.-r.; Yao, C.-h.; Mu, Y.-w.; Wan, J.-g.; Han, M. Structures and magnetic properties of SinNi (n = 1–17) clusters. J. Mol. Struct.: THEOCHEM 2009, 916, 139– 146, DOI: 10.1016/j.theochem.2009.09.027416https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlOks7rE&md5=06d759cced8cc6fc4a91f7c1c0e3e92cStructures and magnetic properties of SinNi (n =1-17) clustersLi, Jian-rong; Yao, Chang-hong; Mu, Yue-wen; Wan, Jian-guo; Han, MinJournal of Molecular Structure: THEOCHEM (2009), 916 (1-3), 139-146CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)The structure, electronic and magnetic properties of SinNi clusters up to n = 17 are systematically investigated using the d.-functional theory (DFT) within the generalized gradient approxn. (GGA). In the ground configurations of SinNi clusters, the equil. site of Ni atom gradually moves from convex, to a surface, and to a concave site as the no. of Si atoms varying from 1 to 17. Starting from n = 8, the Ni atom completely falls into the center of the Si outer frame, forming Ni-encapsulated Si cages. Maximum peaks of second-order energy difference are found at n = 5, 7, 10, 12 and 14, indicating that these clusters possess relatively higher stability. Esp., Si10Ni cluster is more stable. The electronic structures and magnetic properties of SinNi clusters are discussed. The strong hybridization between Ni 4s, 3d, 4p and Si 3s, 3p states leads to the decrease of the gaps between highest-occupied and lowest-unoccupied MOs of SinNi clusters compared with corresponding those of Sin clusters and may be one of important factors which result in SinNi clusters magnetic moment quenched except for Si2Ni cluster.
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417He, J.; Wu, K.; Liu, C.; Sa, R. Stabilities of 3d transition-metal doped Si14 clusters. Chem. Phys. Lett. 2009, 483, 30– 34, DOI: 10.1016/j.cplett.2009.10.052417https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVaisb3F&md5=ff68a0d009f52de40664ad5c65f1ac1aStabilities of 3d transition-metal doped Si14 clustersHe, Jiangang; Wu, Kechen; Liu, Caiping; Sa, RongjianChemical Physics Letters (2009), 483 (1-3), 30-34CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometries, electronic structures, and stabilities of MSi14 clusters (M = Sc-Ni) were studied by using the DFT-B3LYP method. The cage composed of 14 Si atoms can completely encapsulate a 3d transition-metal atom. The binding forces of MSi14 clusters mainly originate from the electrostatic and orbital interactions. In binding (or embedding) energy calcn., the Wigner-Witmer spin conservation rule is needed in the cases of CrSi14 and MnSi14. Only CrSi14 shows simultaneously the highest stability and chem. inertness indicating that only 20-electron rule can be applied to MSi14 species.
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418Wang, J.; Ma, Q.-M.; Xu, R.-P.; Liu, Y.; Li, Y.-C. 3d transition metals: Which is the ideal guest for Sin (n = 15, 16) cages?. Phys. Lett. A 2009, 373, 2869– 2875, DOI: 10.1016/j.physleta.2009.05.072418https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXosVWqtL8%253D&md5=ddee616e2cef0ff9fddde792e1a6b94e3d transition metals: Which is the ideal guest for Sin ( n = 15 , 16 ) cages?Wang, Jing; Ma, Qing-Min; Xu, Rui-Ping; Liu, Ying; Li, You-ChengPhysics Letters A (2009), 373 (32), 2869-2875CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The configurations, stability, and electronic structures of Si15 and Si16 cages with encapsulated 3d transition metal atoms, M@Si15 and M@Si16 (M = Sc, Ti, V, Cr, Mn, Fe, Co, or Ni), have been investigated within the framework of all-electron d. functional theory. The results show that Ti@Si16 and Ti@Si15 have the largest embedding energies in this series and relatively large HOMO-LUMO gaps. This suggests that the titanium atom is an ideal guest for Sin ( n = 15 , 16 ) cages as far as stability is concerned. The Mn atom is found to have a large spin moment even when encapsulated, while the spin moments of Ti, Cr, Fe, and Ni are entirely quenched upon doping into the Si15 and Si16 cage clusters.
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419Zdetsis, A.; Koukaras, E.; Garoufalis, C. A parallel study of Ni@Si12 and Cu@Si12 nanoclusters. J. Math. Chem. 2009, 46, 971– 980, DOI: 10.1007/s10910-009-9549-x419https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVGgsrjP&md5=9f0037ac4bf0417746171210968da44fA parallel study of Ni@Si12 and Cu@Si12 nanoclustersZdetsis, A. D.; Koukaras, E. N.; Garoufalis, C. S.Journal of Mathematical Chemistry (2009), 46 (3), 971-980CODEN: JMCHEG; ISSN:0259-9791. (Springer)The Ni@Si12 and Cu@Si12 clusters are studied in parallel within the framework of the d. functional theory using the hybrid functional of Becke-Lee, Parr and Yang (B3LYP), emphasizing the differences and similarities in structural and electronic properties. The dominant structures for both clusters are a distorted hexagonal structure of Cs symmetry and a distorted octahedral structure of D2d. For Ni@Si12 the two structures are practically isoenergetic whereas for Cu@Si12 the energy difference of the D2d structure from the lowest Cs structure of hexagonal origin is about 0.7 eV, at the B3LYP/TZVP level of theory. Contrary to Cu@Si12 for which the well known Frank-Kasper (FK) structure of C5v symmetry is a real local min. of the energy hyper-surface (although higher by more than 1.6 eV from the global min.), for Ni@Si12 the FK structure is dynamically unstable. The HOMO-LUMO gaps, the binding energies per atom and the embedding energies for Cu@Si12 clusters are smaller by 0.5, 0.1 and 1.1 eV, resp. compared to the Ni@Si12 clusters. This is attributed to different type of bonding in the two clusters.
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420Li, J.-r.; Wang, G.-h.; Yao, C.-h.; Mu, Y.-w.; Wan, J.-g.; Han, M. Structures and magnetic properties of SinMn (n = 1–15) clusters. J. Chem. Phys. 2009, 130, 164514, DOI: 10.1063/1.3123805420https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlsVGnu70%253D&md5=c90d9fcc6449287eb83a4c7f53901f06Structures and magnetic properties of SinMn (n=1-15) clustersLi, Jian-rong; Wang, Guang-hou; Yao, Chang-hong; Mu, Yue-wen; Wan, Jian-guo; Han, MinJournal of Chemical Physics (2009), 130 (16), 164514/1-164514/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structure, electronic, magnetic properties of SinMn clusters up to n=15 are systematically investigated using the d. functional theory within the generalized gradient approxn. In the most stable configurations of SinMn clusters, the equil. site of Mn atom gradually moves from convex, to a surface, and to a concave site as the no. of Si atoms varying from 1 to 15. Starting from n=11, the Mn atom completely falls into the center of the Si outer frame, forming Mn-encapsulated Si cages. Maximum peaks of second-order energy difference are found at n=6, 8, 10, and 12, indicating that these clusters possess relatively higher stability. The electronic structures and magnetic properties of SinMn clusters are discussed. The magnetic moment of SinMn clusters mainly is located on Mn atom. The 3d electrons in Mn atom play a dominant role in the detn. of the magnetism of Mn atom in SinMn clusters. Furthermore, the moment of Mn atom in SinMn clusters exhibits oscillatory behavior and are quenched at n>7 except for n=12, mainly due to the charge transfer, strong hybridization between Mn 4s, 3d, 4p and Si 3s, 3p states. (c) 2009 American Institute of Physics.
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421Reis, C.; Pacheco, J. Vibrational spectra of silicon cage clusters doped with Ti, Zr, or Hf. Phys. Rev. B: Condens. Matter Mater. Phys. 2010, 82, 155440, DOI: 10.1103/PhysRevB.82.155440421https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlKlt7%252FP&md5=84f67f239b9c0e9eebf362a6f98108c8Vibrational spectra of silicon cage clusters doped with Ti, Zr, or HfReis, C. L.; Pacheco, J. M.Physical Review B: Condensed Matter and Materials Physics (2010), 82 (15), 155440/1-155440/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors study the vibrational modes and IR spectra of the exceptionally stable isovalent X @ Si16 (X = Ti, Zr, and Hf) nanoparticles, making use of 1st-principles d.-functional theory. The results predict the existence of high-intensity modes of low frequency. An est. of the electron-phonon coupling strength λ is also provided based on a single-mol. method introduced recently. The large value of λ combined with predicted stability of bulk materials assembled with these nanoparticles suggest that these materials, when appropriately doped, may exhibit high-temp. superconducting properties.
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422Wang, J.; Liu, Y.; Li, Y.-C. Magnetic silicon fullerene. Phys. Chem. Chem. Phys. 2010, 12, 11428– 11431, DOI: 10.1039/b923865d422https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFartb%252FM&md5=d99f5b69a1bd93aae2a510f4dae9b2aeMagnetic silicon fullereneWang, Jing; Liu, Ying; Li, You-ChengPhysical Chemistry Chemical Physics (2010), 12 (37), 11428-11431CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)A metal-encapsulating silicon fullerene, Eu@Si20, was predicted by d. functional theory to be by far the most stable fullerene-like silicon structure. The Eu@Si20 structure is a dodecahedron with D2h symmetry in which the europium atom occupies the center site. The calcd. results show that the europium atom has a large magnetic moment of nearly 7.0 μB. A stable pearl necklace nanowire, constructed by concatenating Eu@Si20 units, with the central europium atom, retains the high spin moment. The magnetic structure of the nanowire indicates potential applications in the fields of spintronics and high-d. magnetic storage.
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423Wang, J.; Liu, Y.; Li, Y.-C. Au@Sin: Growth behavior, stability and electronic structure. Phys. Lett. A 2010, 374, 2736– 2742, DOI: 10.1016/j.physleta.2010.04.068423https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmtlCqtbc%253D&md5=b243d518ac167f15f942bf36670bd537Au@Sin: Growth behavior, stability and electronic structureWang, Jing; Liu, Ying; Li, You-ChengPhysics Letters A (2010), 374 (27), 2736-2742CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The configurations, stability, and electronic structure of Au@Sin (n=1-16) clusters have been investigated within the framework of the d. functional theory at the B3PW91/LanL2DZ and PW91/DNP levels. The results show that the Au atom begins to occupy the interior site for cages as small as Si11 and for Si12 the Au atom completely falls into the interior site forming Au@Si12 cage. A relatively large embedding energy and small HOMO-LUMO gap are also found for this Au@Si12 structure indicating enhanced chem. activity and good electronic transfer properties. All these make Au@Si12 attractive for cluster-assembled materials.
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424Willand, A.; Gramzow, M.; Ghasemi, S. A.; Genovese, L.; Deutsch, T.; Reuter, K.; Goedecker, S. Structural metastability of endohedral silicon fullerenes. Phys. Rev. B: Condens. Matter Mater. Phys. 2010, 81, 201405, DOI: 10.1103/PhysRevB.81.201405424https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvVOisL8%253D&md5=fc8a908cbe44f3a011c937cd1eff60c3Structural metastability of endohedral silicon fullerenesWilland, Alex; Gramzow, Matthias; Alireza Ghasemi, S.; Genovese, Luigi; Deutsch, Thierry; Reuter, Karsten; Goedecker, StefanPhysical Review B: Condensed Matter and Materials Physics (2010), 81 (20), 201405/1-201405/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Endohedrally doped Si20 fullerenes appear as appealing building blocks for nanoscale materials. We investigate their structural stability with an unbiased and systematic global geometry optimization method within d.-functional theory. For a wide range of metal-doping atoms, it was sufficient to explore the Born-Oppenheimer surface for only a moderate no. of local min. to find structures that clearly differ from the initial endohedral cages but are considerably more favorable in terms of energy. Previously proposed structures are thus all metastable.
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425Palagin, D.; Gramzow, M.; Reuter, K. On the stability of “non-magic” endohedrally doped Si clusters: A first-principles sampling study of MSi16+ (M = Ti, V, Cr). J. Chem. Phys. 2011, 134, 244705, DOI: 10.1063/1.3604565425https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXotV2ht78%253D&md5=468727ec4011161c306c8a83cb190d2aOn the stability of "non-magic" endohedrally doped Si clusters: A first-principles sampling study of MSi16+ (M = Ti,V,Cr)Palagin, Dennis; Gramzow, Matthias; Reuter, KarstenJournal of Chemical Physics (2011), 134 (24), 244705/1-244705/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)D.-functional theory is used to study the geometric and electronic structure of cationic Si16+ clusters with a Ti, V, or Cr dopant atom. Through unbiased global geometry optimization based on the basin-hopping approach, we confirm that a Frank-Kasper polyhedron, with the metal atom at the center, represents the ground-state isomer for all three systems. The endohedral cage geometry is thus stabilized even though only VSi16+ achieves electronic shell closure within the prevalent spherical potential model. Our anal. of the electronic structure traces this diminished role of shell closure for the stabilization back to the adaptive capability of the metal-Si bonding, which is more the result of a complex hybridization than the originally proposed mere formal charge transfer. The resulting flexibility of the metal-Si bond can also help to stabilize "non-magic" cage-dopant combinations, which suggests that a wider range of materials may eventually be cast into this useful geometry for cluster-assembled materials. (c) 2011 American Institute of Physics.
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426Cantera-López, H.; Balbás, L.; Borstel, G. First-principles calculations of structural and electronic properties of Ta-doped Si clusters, wires, and bulk systems. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 83, 075434, DOI: 10.1103/PhysRevB.83.075434426https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXis1Cntbs%253D&md5=8c3c5e7bbe422a493ccb291634f76bb9First-principles calculations of structural and electronic properties of Ta-doped Si clusters, wires, and bulk systemsCantera-Lopez, H.; Balbas, L. C.; Borstel, G.Physical Review B: Condensed Matter and Materials Physics (2011), 83 (7), 075434/1-075434/9CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Recent expts. have shown that Ta@Si16+ is a very stable cation from which it should be possible to create Si-based cluster assembled materials. In this paper we have studied, by means of first-principles spin-dependent generalized gradient approxn. calcns., the structural and electronic properties of the following systems: (i) Ta@Sin+ clusters in the range n=14-18; (ii) (Ta@Si16F)m aggregates with sizes m=1-8 formed by Ta@Si16F mols.; (iii) infinite wires formed by stacking triangular (Ta@Si16F)3 aggregates twisted 60° to each other along the vertical axis; and (iv) the fcc phase of bulk Ta@Si16F. The min.-energy Ta@Si16+ cluster shows C3v symmetry, having 40 meV smaller total energy than a fullerenelike D4d isomer. However, the mol. Ta@Si16F formed with that D4d isomer is 40 meV more stable than that formed with the C3v one. We have optimized several [Ta@Si16F]n aggregates (n=1-8) which contain the Ta@Si16 unit with D4d symmetry. The more bound (Ta@Si16F)6 aggregate is formed by stacking vertically two triangular (Ta@Si16F)3 aggregates which are twisted 60° to each other. The infinite wire formed with that (Ta@Si16F)6 aggregate as the unit cell has a cohesive energy 1.88 eV and a small HOMO-lowest occupied MO gap. We have optimized also a metastable fcc bulk phase having the Ta@Si16F supermol. as the unit cell. A Birch-Murnaghan fit to that phase produces a cohesive energy 0.84 eV at lattice const. 12.27 A, with bulk modulus 7.55 GPa and a phase stability to isotropic compression smaller than 0.75 GPa. That phase is nonmagnetic and shows a band gap of 0.20 eV. Using the values of hardness of Ta@Si16F mols., we estd. a correction enhancement factor ∼3 to that small band gap. For that metastable solid we performed a 13.5-ps run of first-principles mol. dynamics annealing at 300 K and const. vol., and we found that the Ta@Si16F supermol. in the fcc cell becomes severely distorted after the first 5 ps.
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427Oña, O. B.; Ferraro, M. B.; Facelli, J. C. Transition from exo to endo Cu absorption in CuSin clusters: A genetic algorithms density functional theory study. Mol. Simul. 2011, 37, 678– 688, DOI: 10.1080/08927020903583830427https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXovFGgsro%253D&md5=9001fc69da19d68cd4b595a666a7b33cTransition from exo to endo Cu absorption in CuSin clusters: a genetic algorithms density functional theory studyOna, Ofelia B.; Ferraro, Marta B.; Facelli, Julio C.Molecular Simulation (2011), 37 (8), 678-688CODEN: MOSIEA; ISSN:0892-7022. (Taylor & Francis Ltd.)The characterization and prediction of the structures of metal silicon clusters is important for nanotechnol. research because these clusters can be used as building blocks for nanodevices, integrated circuits and solar cells. Several authors have postulated that there is a transition between exo and endo absorption of Cu in Sin clusters and showed that, for n larger than 9, it is possible to find endohedral clusters. Unfortunately, no global searches have confirmed this observation, which is based on local optimizations of plausible structures. Here, we use parallel genetic algorithms (GAs), as implemented in our modified genetic algorithms (MGAC) software, directly coupled with d. functional theory energy calcns. to show that the global search of CuSin cluster structures does not find endohedral clusters for n < 8 but finds them for n ≥ 10.
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428Liu, T.-g.; Zhao, G.-f.; Wang, Y.-x. Structural, electronic and magnetic properties of GdSin (n = 1–17) clusters: A density functional study. Phys. Lett. A 2011, 375, 1120– 1127, DOI: 10.1016/j.physleta.2011.01.023428https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1Cju7c%253D&md5=8f04062dcba3f9b1ddeda5be0c834c96Structural, electronic and magnetic properties of GdSin (n=1-17) clusters: A density functional studyLiu, Tai-gang; Zhao, Gao-feng; Wang, Yuan-xuPhysics Letters A (2011), 375 (7), 1120-1127CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The geometries, stabilities, electronic and magnetic properties of GdSin (n=1-17) clusters have been investigated systematically by using d. functional theory (DFT) with the generalized gradient approxn. (GGA). We find that the Gd atom in the lowest-energy configuration gradually moves from convex to surface, and to the interior site as the no. of Si atom varies from 1 to 17. Furthermore, from GdSi16, Gd atom in GdSi16 cluster completely falls into the center of the Si framework and forms a fullerene cage. On the basis of the at. av. binding energy [Eb(n)], the second difference in energy (Δ2E) and VIP, we predict that the magic no. of GdSin (n=1-17) clusters should be 5, 11 and 16, and these clusters should be abundant in the mass spectra when n=5, 11 and 16. The magnetic moments of the GdSin clusters are also studied. It is found that the total magnetic moments and the magnetic moments on Gd of GdSin clusters are large, and they do not quench when Gd is encapsulated in Si outer framework cage, which is to a large extent due to the fact that the Gd 4f electrons hardly interact with the silicon cage.
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429Ziella, D. H.; Caputo, M. C.; Provasi, P. F. Study of geometries and electronic properties of AgSin clusters using DFT/TB. Int. J. Quantum Chem. 2011, 111, 1680– 1693, DOI: 10.1002/qua.22815429https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvVKju74%253D&md5=4884311930675114359412228e7b18efStudy of geometries and electronic properties of AgSin clusters using DFT/TBZiella, D. H.; Caputo, M. C.; Provasi, P. F.International Journal of Quantum Chemistry (2011), 111 (7/8), 1680-1693CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)We present a theor. study of the structures of silver silicon clusters, AgSin, n = 1-15, using d. functional tight binding methods. We discuss in detail the search for silicon clusters stabilized by silver dopage, their dissocn. paths, and electronic properties. We also investigate the properties of silver encapsulated structures and compare them with those obtained when replacing the silver atom by different metals. Our results are checked against exptl. measurements when available. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010.
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430Dognon, J.-P.; Clavaguéra, C.; Pyykkö, P. A new, centered 32-electron system: The predicted [U@Si20]6–-like isoelectronic series. Chem. Sci. 2012, 3, 2843– 2848, DOI: 10.1039/c2sc20448g430https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFWns7zI&md5=69933fdb50e4df9cc594ce9cfb8431b6A new, centered 32-electron system: the predicted [U@Si20]6--like isoelectronic seriesDognon, Jean-Pierre; Clavaguera, Carine; Pyykkoe, PekkaChemical Science (2012), 3 (9), 2843-2848CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)In addn. to Lewis' octets and Langmuir's 18-electron principle, 32-electron centered systems are possible. We now propose a new, third example on 32e-bonding between a central metal atom and a ligand cage. Moreover, these actinide-filled Si20 clusters could lead to novel silicon nanostructures.
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431Xu, H.-G.; Wu, M. M.; Zhang, Z.-G.; Yuan, J.; Sun, Q.; Zheng, W. Photoelectron spectroscopy and density functional calculations of CuSin– (n = 4–18) clusters. J. Chem. Phys. 2012, 136, 104308, DOI: 10.1063/1.3692685431https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjvVers7w%253D&md5=013852c946bd74ee90ebc1ecb24081c5Photoelectron spectroscopy and density functional calculations of CuSin- (n = 4-18) clustersXu, Hong-Guang; Wu, Miao Miao; Zhang, Zeng-Guang; Yuan, Jinyun; Sun, Qiang; Zheng, WeijunJournal of Chemical Physics (2012), 136 (10), 104308/1-104308/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We conducted a combined anion photoelectron spectroscopy and DFT-B3LYP study on the structural evolution of copper-doped silicon clusters, CuSin- (n = 4-18). Based on the comparison between the expts. and theor. calcns., CuSi12- is suggested to be the smallest fully endohedral cluster. The low-lying isomers of CuSin- with n ≥ 12 are dominated by endohedral structures, those of CuSin- with n < 12 are dominated by exohedral structures. The most stable structure of CuSi12- is a double-chair endohedral structure with the copper atom sandwiched between two chair-style Si6 rings or, in another word, encapsulated in a distorted Si12 hexagonal prism cage. CuSi14- has an interesting C3h symmetry structure, in which the Si14 cage is composed by three four-membered rings and six five-membered rings. (c) 2012 American Institute of Physics.
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432Kong, X.; Xu, H.-G.; Zheng, W. Structures and magnetic properties of CrSin– (n = 3–12) clusters: Photoelectron spectroscopy and density functional calculations. J. Chem. Phys. 2012, 137, 064307, DOI: 10.1063/1.4742065432https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFKms7zE&md5=c68b8938c05b0cb92a42bce80f300a70Structures and magnetic properties of CrSin- (n = 3-12) clusters. Photoelectron spectroscopy and density functional calculationsKong, Xiangyu; Xu, Hong-Guang; Zheng, WeijunJournal of Chemical Physics (2012), 137 (6), 064307/1-064307/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Cr-doped Si clusters, CrSin- (n = 3-12), were investigated with anion photoelectron spectroscopy and d. functional theory calcns. The combination of exptl. measurement and theor. calcns. reveals that the onset of endohedral structure in CrSin- clusters occurs at n = 10 and the magnetic properties of the CrSin- clusters are correlated to their geometric structures. The most stable isomers of CrSin- from n = 3-9 have exohedral structures with magnetic moments of 3-5 μB while those of CrSi10-, CrSi11-, and CrSi12- have endohedral structures and magnetic moments of 1μB. (c) 2012 American Institute of Physics.
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433Kong, X.-Y.; Deng, X.-J.; Xu, H.-G.; Yang, Z.; Xu, X.-L.; Zheng, W.-J. Photoelectron spectroscopy and density functional calculations of AgSin– (n = 3–12) clusters. J. Chem. Phys. 2013, 138, 244312, DOI: 10.1063/1.4811659433https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVaitL%252FI&md5=d5197cdd035b437f085f23ebc867a398Photoelectron spectroscopy and density functional calculations of AgSin- (n = 3-12) clustersKong, Xiang-Yu; Deng, Xiao-Jiao; Xu, Hong-Guang; Yang, Zheng; Xu, Xi-Ling; Zheng, Wei-JunJournal of Chemical Physics (2013), 138 (24), 244312/1-244312/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We investigated the structural evolution and electronic properties of AgSin- (n = 3-12) clusters using anion photoelectron spectroscopy and d. functional theory calcns. The vertical detachment energies and adiabatic detachment energies of AgSin- (n = 3-12) clusters were estd. from their photoelectron spectra. The structures of the AgSin- (n = 3-12) clusters were tentatively assigned based on the comparison of theor. calcns. and exptl. measurements. The studies show that the structures of AgSin- (n = 3-12) clusters are dominated by exohedral structures with the Ag atom occupying the low coordinated sites. No endohedral structure has been found for AgSin- clusters with n ≤ 12. (c) 2013 American Institute of Physics.
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434Ma, L.; Wang, J.; Wang, G. Site-specific analysis of dipole polarizabilities of heterogeneous systems: Iron-doped Sin (n = 1–14) clusters. J. Chem. Phys. 2013, 138, 094304, DOI: 10.1063/1.4793276434https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtlOisbg%253D&md5=404e908e6bfbfb27c0175c94bd494801Site-specific analysis of dipole polarizabilities of heterogeneous systems: Iron-doped Sin (n = 1-14) clustersMa, Li; Wang, Jianguang; Wang, GuanghouJournal of Chemical Physics (2013), 138 (9), 094304/1-094304/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Following the recent work of decompg. the total dipole moment and polarizability of a homogeneous system into site-specific contributions, we extend the study to the heterogeneous systems of iron-doped Sin (n = 1-14) clusters by introducing a weighting function. The structure-/shape- and size-specific aspects of the dipole moments and polarizabilities of SinFe (n = 1-14) clusters are analyzed and compared with pure silicon clusters. It is shown that the polarizabilities assocd. with the individual constituent atoms vary considerably with the structure/shape of the cluster and the location of the atom or site within a given structure. For atoms at peripheral sites, the polarizabilities are substantially larger than atoms at the interior sites, and the more peripheral an atom is, the larger is its polarizability. The polarizability of the Fe atom in SinFe clusters decreases as the cluster size increases. This is related to the position of Fe atom in SinFe clusters and indicates significant screening of the interior of the cluster by its surface. The correlation between the anisotropy of the total polarizability and the anisotropy of the cluster shape is also analyzed. Comparing with pure Sin clusters, the polarizabilities of Si atoms are increased after Fe atom doping. The structures are more compact for SinFe than the same sizes of Sin+1 clusters and the polarizabilities of SinFe are smaller than Sin+1 for the sizes of n = 7-14. (c) 2013 American Institute of Physics.
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435Oliveira, M.; Rivelino, R.; de Brito Mota, F.; Gueorguiev, G. K. Optical properties and quasiparticle band gaps of transition-metal atoms encapsulated by silicon cages. J. Phys. Chem. C 2014, 118, 5501– 5509, DOI: 10.1021/jp409967a435https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXis1ensr4%253D&md5=6bc9ad4eb6c37c76e5defc88aa197429Optical Properties and Quasiparticle Band Gaps of Transition-Metal Atoms Encapsulated by Silicon CagesOliveira, M. I. A.; Rivelino, R.; de Brito Mota, F.; Gueorguiev, G. K.Journal of Physical Chemistry C (2014), 118 (10), 5501-5509CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Semiconductors assembled upon nanotemplates consisting of metal-encapsulating Si cage clusters (M@Si) have been proposed as prospective materials for nanodevices. To make an accurate and systematic prediction of the optical properties of such M@Si clusters, which represent a new type of metal-silicon hybrid material for components in nanoelectronics, we have performed first-principles calcns. of the electronic properties and quasiparticle band gaps for a variety of M@Si12 (M = Ti, Cr, Zr, Mo, Ru, Pd, Hf, and Os) and M@Si16 (M = Ti, Zr, and Hf) clusters. At first stage, the electronic structure calcns. have been performed within plane-wave d. functional theory in order to predict equil. geometries, polarizabilities, and optical absorption spectra of these endohedral cagelike clusters. The quasiparticle calcns. were performed within the GW approxn., which predict that all of these systems are semiconductors exhibiting large band gaps. The present results have demonstrated that the independent-particle absorption spectra of M@Si, calcd. within the local d. or generalized gradient approxns. to d. functional theory, are dramatically influenced by many-body effects. On av., the quasiparticle band gaps were significantly increased, in comparison with the independent-particle gaps, giving values in the 2.45-5.64 eV range. Consequently, the inclusion of many-body effects in the electron-electron interaction, and going beyond the mean-field approxn. of independent particles, might be essential to realistically describe the optical spectra of isolated M@Si clusters, as well as their cluster-assembled materials.
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436Oliveira, M. J.; Medeiros, P. V.; Sousa, J. R.; Nogueira, F.; Gueorguiev, G. K. Optical and magnetic excitations of metal-encapsulating Si cages: A systematic study by time-dependent density functional theory. J. Phys. Chem. C 2014, 118, 11377– 11384, DOI: 10.1021/jp4096562436https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXns1Cnsb0%253D&md5=7cee1d64d3e750103d5898317b2cbea5Optical and Magnetic Excitations of Metal-Encapsulating Si Cages: A Systematic Study by Time-Dependent Density Functional TheoryOliveira, Micael J. T.; Medeiros, Paulo V. C.; Sousa, Jose R. F.; Nogueira, Fernando; Gueorguiev, Gueorgui K.Journal of Physical Chemistry C (2014), 118 (21), 11377-11384CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A systematic study of the optical and magnetic excitations of 12 MSi12 and four MSi10 transition metal encapsulating Si cages has been carried out by employing real time time-dependent d. functional theory. Criteria for the choice of transition metals (M) are clusters' stability, synthesizability, and diversity. It was found that both the optical absorption and the spin-susceptibility spectra are mainly detd. by, in decreasing order of importance, (1) the cage shape, (2) the group in the Periodic Table to which M belongs, and (3) the period of M in the Periodic Table. Cages with similar structures and metal species that are close to each other in the Periodic Table possess spectra sharing many similarities; for example, the optical absorption spectra of the MSi12 (M = V, Nb, Ta, Cr, Mo, and W), which are highly sym. and belong to groups 4 and 5 of the Periodic Table, all share a very distinctive peak at around 4 eV. In all cases, although some of the obsd. transitions are located at the Si skeleton of the cages, the transition metal species is always significant for the optical absorption and the spin-susceptibility spectra. Our results provide fingerprint data for identification of gas-phase MSi12 and MSi10 by optical absorption spectroscopy.
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437Liu, T.-G.; Zhang, W.-Q.; Li, Y.-L. First-principles study on the structure, electronic and magnetic properties of HoSin (n = 1–12, 20) clusters. Front. Phys. 2014, 9, 210– 218, DOI: 10.1007/s11467-013-0398-5There is no corresponding record for this reference.
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438Zhao, R.-N.; Han, J.-G.; Duan, Y. Density functional theory investigations on the geometrical and electronic properties and growth patterns of Sin (n = 10–20) clusters with bimetal Pd2 impurities. Thin Solid Films 2014, 556, 571– 579, DOI: 10.1016/j.tsf.2014.02.019438https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtlGgtLc%253D&md5=9e545173800b955252ee5ed85a0227eaDensity Functional theory investigations on the geometrical and electronic properties and growth patterns of Sin (n = 10-20) clusters with bimetal Pd2 impuritiesZhao, Run-Ning; Han, Ju-Guang; Duan, YuhuaThin Solid Films (2014), 556 (), 571-579CODEN: THSFAP; ISSN:0040-6090. (Elsevier B.V.)The geometrical and electronic properties and growth patterns of the bimetal Pd2 doped Sin (n = 10-20) clusters have been studied systematically by d. functional theory. The growth-pattern behaviors, relative stabilities, and chem. bonding of these clusters are presented and discussed. The optimized geometries exhibit that the dominant growth patterns of Pd2Sin (n = 10-20) are based on the pentagonal prism PdSi10. The bimetal Pd2 is doped on the opened cage-like silicon clusters (Sin) with the range of size n = 10-15, while doped on bigger silicon clusters (Sin, n = 16-20), the Pd2 are completely encapsulated inside Sin frames. The geometrical configurations of the encapsulated Pd2 in the Sin frames are varied due to the interactions between Pd2 and Sin frames. The calcd. fragmentation energies reveal that the remarkable stable Pd2Sin clusters with n = 11, 13, 16, 18, and 20 are obsd. Among all different-size clusters, the Pd2-doped Si16 is the most stable cluster. Particularly, the cage-like Pd2Si16 geometry is obviously distinct as compared to the single transition metal doped silicon cluster. Interestingly, the crit. size of geometry transition is explored at n = 16. Natural population anal. manifests that the charge-transfer phenomena in the Pd2-doped Sin clusters are similar to those of the single TM doped silicon clusters. In addn., the Pd2Sin (n = 10, 13, 14, 16, and 17) isomers have enhanced chem. stabilities because of their larger gaps between the highest occupied orbital and the lowest unoccupied orbital.
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439Borshch, N.; Kurganskii, S. Geometric structure, electron-energy spectrum, and growth of anionic scandium-silicon clusters ScSin- (n = 6–20). J. Appl. Phys. 2014, 116, 124302, DOI: 10.1063/1.4896528439https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsF2lsL%252FO&md5=c5ed331024b80da940b5f46f60ff5a53Geometric structure, electron-energy spectrum, and growth of anionic scandium-silicon clusters ScSin- (n = 6-20)Borshch, N.; Kurganskii, S.Journal of Applied Physics (Melville, NY, United States) (2014), 116 (12), 124302/1-124302/8CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)Results of the geometric structure optimization and calcd. electron spectra of anion ScSi-n clusters (n = 6-20) are presented. Calcns. were carried out within the d. functional theory DFT-B3LYP framework. Real geometric structures of ScSin- clusters were established by the comparison of calcd. and known exptl. data. Formation of stable endohedral clusters is possible for n ≥ 14, for clusters with smaller no. of silicon atoms exohedral or longitudinal structures are preferable. (c) 2014 American Institute of Physics.
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440Abreu, M. B.; Reber, A. C.; Khanna, S. N. Does the 18-electron rule apply to CrSi12?. J. Phys. Chem. Lett. 2014, 5, 3492– 3496, DOI: 10.1021/jz501868t440https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhs1Cit7bM&md5=97cc238911272a0e7f146524f1976e13Does the 18-Electron Rule Apply to CrSi12?Abreu, Marissa Baddick; Reber, Arthur C.; Khanna, Shiv N.Journal of Physical Chemistry Letters (2014), 5 (20), 3492-3496CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Understanding the bonding between silicon and transition metals is valuable for devising strategies for incorporating magnetic species into silicon. CrSi12 is the std. example of a cluster whose apparent high stability has been explained by the 18-electron rule. We critically examine the bonding and nature of stability of CrSi12 and show that its electronic structure does not conform to the 18-electron rule. Through theor. studies, we find that CrSi12 has 16 effective valence electrons assigned to the Cr atom and an unoccupied 3dz2 orbital. We demonstrate that the cluster's apparent stability is rooted in a crystal field-like splitting of the 3d orbitals analogous to that of square planar complexes. CrSi14 is shown to follow the 18-electron rule and exhibits all conventional markers characteristic of a magic cluster.
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441Zhao, R.-N.; Han, J.-G. Geometrical stabilities and electronic properties of Sin (n = 12–20) clusters with rare earth holmium impurity: A density functional investigation. RSC Adv. 2014, 4, 64410– 64418, DOI: 10.1039/C4RA11828F441https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVGhsbrF&md5=b6a0a1c32ed45af3396a7d013bb241b1Geometrical stabilities and electronic properties of Sin (n = 12-20) clusters with rare earth holmium impurity: a density functional investigationZhao, Run-Ning; Han, Ju-GuangRSC Advances (2014), 4 (110), 64410-64418CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)HoSin (n = 12-20) clusters with different spin states have been systematically investigated by using d. functional theory with the generalized gradient approxn. The total energies, growth-pattern and equil. geometries as well as the APT charges of the HoSin (n = 12-20) clusters are calcd. The relative stabilities in terms of the calcd. at. averaged binding energies and fragmentation energies are discussed, revealing that the cake-like HoSin (n = 16, 18, 20) clusters have enhanced stabilities. Furthermore, the HOMO - LUMO (HOMO-LUMO) gaps of the HoSin (n = 12-17) are above 1.55 eV while HoSi16 has the largest one (1.95 eV). Interestingly, the calcd. dipole moments of the cake-like HoSin (n = 16, 18, 20) clusters are very small, corresponding to the global min. According to the calcd. APT charges of the Ho atom in the HoSin (n = 12-20) clusters, the contribution of charge-transfer to the stability of HoSin clusters is briefly discussed, manifesting that the charges in HoSin clusters transfer from the Si atoms to the Ho atom. Addnl., the optimized geometries show that the rare earth Ho atom is completely encapsulated into the center of the Si frame at n = 15. This finding is in good agreement with the available exptl. results.
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442Xu, H.-G.; Kong, X.-Y.; Deng, X.-J.; Zhang, Z.-G.; Zheng, W.-J. Smallest fullerene-like silicon cage stabilized by a V2 unit. J. Chem. Phys. 2014, 140, 024308, DOI: 10.1063/1.4861053442https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmtlSluw%253D%253D&md5=957ddd12a06a3426cb17b8356480b5b7Smallest fullerene-like silicon cage stabilized by a V2 unitXu, Hong-Guang; Kong, Xiang-Yu; Deng, Xiao-Jiao; Zhang, Zeng-Guang; Zheng, Wei-JunJournal of Chemical Physics (2014), 140 (2), 024308/1-024308/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The authors conducted a combined anion photoelectron spectroscopy and d. functional theory study on V2Si20 cluster. The V2Si20 cluster has an elongated dodecahedron cage structure with a V2 unit encapsulated inside the cage. It is the smallest fullerene-like silicon cage and can be used as a building block to make cluster-assembled materials, such as pearl-chain style nanowires. (c) 2014 American Institute of Physics.
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443Huang, X.; Xu, H.-G.; Lu, S.; Su, Y.; King, R.; Zhao, J.; Zheng, W. Discovery of a silicon-based ferrimagnetic wheel structure in VxSi12– (x = 1–3) clusters: Photoelectron spectroscopy and density functional theory investigation. Nanoscale 2014, 6, 14617– 14621, DOI: 10.1039/C4NR03130J443https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFeisb3N&md5=9a5a1cc90ad64b700b8b60dfca34f4a5Discovery of a silicon-based ferrimagnetic wheel structure in VxSi12- (x = 1-3) clusters: photoelectron spectroscopy and density functional theory investigationHuang, Xiaoming; Xu, Hong-Guang; Lu, Shengjie; Su, Yan; King, R. B.; Zhao, Jijun; Zheng, WeijunNanoscale (2014), 6 (24), 14617-14621CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Our studies show that VSi12- adopts a V-centered hexagonal prism with a singlet spin state. The addn. of the second V atom leads to a capped hexagonal antiprism for V2Si12- in a doublet spin state. Most interestingly, V3Si12- exhibits a ferrimagnetic, bicapped hexagonal antiprism wheel-like structure with a total spin of 4μB.
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444Huang, X.; Lu, S.-J.; Liang, X.; Su, Y.; Sai, L.; Zhang, Z.-G.; Zhao, J.; Xu, H.-G.; Zheng, W. Structures and electronic properties of V3Sin– (n = 3–14) clusters: A combined ab Initio and experimental study. J. Phys. Chem. C 2015, 119, 10987– 10994, DOI: 10.1021/jp5112845444https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFOgsbjJ&md5=322d1228decdbd72b683b2e73a696d48Structures and Electronic Properties of V3Sin- (n = 3-14) Clusters: A Combined Ab Initio and Experimental StudyHuang, Xiaoming; Lu, Sheng-Jie; Liang, Xiaoqing; Su, Yan; Sai, Linwei; Zhang, Zeng-Guang; Zhao, Jijun; Xu, Hong-Guang; Zheng, WeijunJournal of Physical Chemistry C (2015), 119 (20), 10987-10994CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Vanadium-doped silicon cluster anions, V3Sin- (n = 3-14), have been generated by laser vaporization and investigated by anion photoelectron spectroscopy. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) of these clusters were obtained. Meanwhile, genetic algorithm (GA) combined with d. functional theory (DFT) calcns. are employed to det. their ground-state structures systematically. Excellent agreement is found between theory and expt. Among the V3Sin- clusters, V3Si5-, V3Si9-, and V3Si12- are relatively more stable. Generally speaking, three V atoms prefer to stay close with others and form strong V-V bonds. Starting from V3Si11-, cage configurations with one interior V atom emerge.
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445Lin, L.; Yang, J. Small copper-doped silicon clusters CuSin (n = 4–10) and their anions: Structures, thermochemistry, and electron affinities. J. Mol. Model. 2015, 21, 155, DOI: 10.1007/s00894-015-2702-5445https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2MfntlWhuw%253D%253D&md5=bd65012a857b93cd3f70a54385c362f3Small copper-doped silicon clusters CuSin (n = 4-10) and their anions: structures, thermochemistry, and electron affinitiesLin Lin; Yang JucaiJournal of molecular modeling (2015), 21 (6), 155 ISSN:.The structures and energies of copper-doped small silicon clusters CuSi n (n = 4-10) and their anions were investigated systematically using CCSD(T)/aug-cc-pVTZ-DK//MP2/6-31G(2df,p), G4//MP2/6-31G(2df,p), and the B3LYP/6-311+G* basis set. The performance of the methods used for the prediction of energetic and thermodynamic properties was evaluated. Comparing experimental [Xu et al. (2012) J Chem Phys 136:104308] and theoretical calculations, it was concluded that the CCSD(T) results are very accurate and exhibit the best performance; the mean absolute deviation from experimental data was 0.043 eV. The excellent agreement of vertical detachment energy (VDE) between experimental results and CCSD(T) calculations indicates that the ground state structures of CuSi n (-) (n = 4-10) presented in this paper are reliable. For CuSi10, assigning 2.90±0.08 eV to the experimental adiabatic electron affinity (AEA) and 3.90±0.08 eV to the VDE is more reasonable than to 3.46±0.08 eV and 3.62±0.08 eV, respectively, based on the CCSD(T) calculations and the previous photoelectron spectrum of CuSi10 (-) (Xu et al., op. cit.). The AEAs of CuSi n (n = 4-10), excluding CuSi7, are in excellent agreement with experimental data, showing that the ground state structures of CuSi n (n = 4-6, 8-10) reported in this paper are reliable. CuSi10 is suggested to be the smallest endohedral ground state structure. However, adding an additional electron to CuSi10 pulls out the Cu atom from the center location, forming an exohedral ground state structure of CuSi10 (-). The charge transfer and dissociation energy of Cu from CuSi n and their anions determined to examine the nature of bonding and their relative stabilities.
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446Abreu, M. B.; Reber, A. C.; Khanna, S. N. Making sense of the conflicting magic numbers in WSin clusters. J. Chem. Phys. 2015, 143, 074310, DOI: 10.1063/1.4928755446https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlOgsb7K&md5=99f99de65fd50391b94260c3a684d59cMaking sense of the conflicting magic numbers in WSin clustersAbreu, Marissa Baddick; Reber, Arthur C.; Khanna, Shiv N.Journal of Chemical Physics (2015), 143 (7), 074310/1-074310/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)First principles studies on the geometric structure, stability, and electronic structure of WSin clusters, n = 6-16, have been carried out to show that the obsd. differing "magic sizes" for WSin clusters are assocd. with the nature of the growth processes. The WSi12 cluster, obsd. as a magic species in expts. reacting transition metal ions with silane, is not stable due to a filled shell of 18 electrons, as previously proposed, but due to its at. structure that arrests further growth because of an endohedral transition metal site. In fact, it is found that all of these clusters, n = 6-16, have filled 5d shells except for WSi12, which has a 5d8 configuration that is caused by crystal field splitting. The stability of WSi15+, obsd. as highly stable in clusters generated by vaporizing silicon and metal carbonyls, is shown to be assocd. with a combination of geometric and electronic features. The findings are compared with previous results on CrSin clusters. (c) 2015 American Institute of Physics.
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447Chauhan, V.; Abreu, M. B.; Reber, A. C.; Khanna, S. N. Geometry controls the stability of FeSi14. Phys. Chem. Chem. Phys. 2015, 17, 15718– 15724, DOI: 10.1039/C5CP01386K447https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXosFKksbw%253D&md5=c45fb58bfe4d0a4db679ee6bfbc820ddGeometry controls the stability of FeSi14Chauhan, Vikas; Abreu, Marissa Baddick; Reber, Arthur C.; Khanna, Shiv N.Physical Chemistry Chemical Physics (2015), 17 (24), 15718-15724CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)First-principles DFT-PBE theor. studies have been carried out to investigate the stability of Sin cages impregnated with a Fe atom. It is shown that FeSi9, FeSi11, and FeSi14 clusters exhibit enhanced local stability as seen through an increase in Si binding energy, Fe embedding energy, the gap between the HOMO and the LUMO, and the Ionization Potential (IP). The conventional picture for the stability of such species combines an assumption of electron precise bonding with the 18-electron rule; however, we find this to be inadequate to explain the enhanced stability in FeSi11 and FeSi14 because the d-band is filled for all FeSin clusters for n ≥ 9. FeSi14 is shown to be the most stable due to a compact and highly sym. Si14 cage with octahedral symmetry that allows better mixing between Fe 3d- and Si 3p-electronic states.
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448Goicoechea, J. M.; McGrady, J. E. On the structural landscape in endohedral silicon and germanium clusters, M@Si12 and M@Ge12. Dalton Trans. 2015, 44, 6755– 6766, DOI: 10.1039/C4DT03573A448https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVWms70%253D&md5=ae6d46d385fd6bfe6641af51c2559a79On the structural landscape in endohedral silicon and germanium clusters, M@Si12 and M@Ge12Goicoechea, Jose M.; McGrady, John E.Dalton Transactions (2015), 44 (15), 6755-6766CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)Amongst the endohedral clusters of the tetrel elements, M@En, the 12-vertex species are unique in that three completely different geometries, the icosahedron (Ih, [Ni@Pb12]2-), the hexagonal prism (HP, Cr@Si12) and the bicapped pentagonal prism (BPP, [Ru@Ge12]3-) have been identified in stable mols. We explore here the origins of this structural diversity by comparing stability patterns across isovalent and isoelectronic series, M@Si12, M@Ge12 and [M@Ge12]3-. The BPP structure dominates the structural landscape for high valence electron counts (57-60) while the HP has a rather narrower window of stability around the 54-56 count. Moreover the preference for an HP structure is unique to silicon: in no case is a rigorously D6h-sym. structure the global min. for M@Ge12. Distortions from the high-symmetry limits, where present, can be traced to degeneracies or near-degeneracies in the frontier orbital domains. In all cases the structure adopted is that which maximizes the delocalization of electron d. between the metal and the cluster cage, such that both components attain stable electronic configurations.
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449Arcisauskaite, V.; Fijan, D.; Spivak, M.; de Graaf, C.; McGrady, J. E. Biradical character in the ground state of [Mn@Si12]+: A DFT and CASPT2 study. Phys. Chem. Chem. Phys. 2016, 18, 24006– 24014, DOI: 10.1039/C6CP03534E449https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht12ks7vN&md5=9837f6574d60270998e2b6b4753feff1Biradical character in the ground state of [Mn@Si12]+: a DFT and CASPT2 studyArcisauskaite, Vaida; Fijan, Domagoj; Spivak, Mariano; Graaf, Coen de; McGrady, John E.Physical Chemistry Chemical Physics (2016), 18 (34), 24006-24014CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Both d. functional theory and multi-configurational ab initio (CASPT2) calcns. are used to explore the potential energy surface of the hexagonal prismatic cluster [Mn@Si12]+. Unlike isoelectronic Cr@Si12, the ground state is a biradical, with triplet and open-shell singlet states lying very close in energy. The results are discussed in the context of recent exptl. studies using infra-red multiple photon dissocn. spectroscopy and X-ray MCD spectroscopy.
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450Xia, X. X.; Hermann, A.; Kuang, X. Y.; Jin, Y. Y.; Lu, C.; Xing, X. D. Study of the structural and electronic properties of neutral and charged niobium-doped silicon clusters: Niobium encapsulated in silicon cages. J. Phys. Chem. C 2016, 120, 677– 684, DOI: 10.1021/acs.jpcc.5b09453450https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVGrsLvK&md5=14a5645da017969b053621dc48b5c585Study of the Structural and Electronic Properties of Neutral and Charged Niobium-Doped Silicon Clusters: Niobium Encapsulated in Silicon CagesXia, Xin Xin; Hermann, Andreas; Kuang, Xiao Yu; Jin, Yuan Yuan; Lu, Cheng; Xing, Xiao DongJournal of Physical Chemistry C (2016), 120 (1), 677-684CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We performed systematic structure searches for low energy structures of neutral and singly charged niobium-doped silicon clusters NbSinQ (n = 2-20; Q = 0, ± 1) by means of the CALYPSO structure searching method. A large population of low energy clusters is collected from the unbiased structure search. Subsequent geometry optimizations using d.-functional theory with the B3LYP exchange-correlation functional are carried out to det. structural patterns and relative stabilities of various low energy candidates for Nb-doped silicon clusters. Based on the calcd. binding energies along with measured photoelectron spectroscopy data, we are able to confirm that our lowest energy structures are the true min. It is shown that the localized position of the Nb impurity atom in NbSin0/±1 clusters gradually moves from the convex capping position, to surface-substituted, to the concave, and in the end to the encapsulated state as the no. of Si atoms increases from 2 to 20. The lowest energy isomer of both neutral and anionic NbSi12 cluster is very stable in a high-symmetry endohedral D6h structure in which the Nb atom is placed at the center of a regular hexagonal prism of Si atoms. This makes it an attractive building block for cluster-assembled materials.
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451Phi, N. D.; Trung, N. T.; Janssens, E.; Ngan, V. T. Electron counting rules for transition metal-doped Si12 clusters. Chem. Phys. Lett. 2016, 643, 103– 108, DOI: 10.1016/j.cplett.2015.11.025451https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFWqtrzI&md5=180087763a0945263ac46ef7e59e3498Electron counting rules for transition metal-doped Si12 clustersPhi, Nguyen Duy; Trung, Nguyen Tien; Janssens, Ewald; Ngan, Vu ThiChemical Physics Letters (2016), 643 (), 103-108CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Application of the phenomenol. shell model (PSM) provides an explanation for the enhanced stability of Si12Cr and Si12Fe clusters and relative cluster stability along the Si12M (M = Sc-Ni) series. Sequence of orbital shells in PSM is mostly detd. by the confining potential, which depends on the cluster shape. In D6h hexagonal prism geometry, degenerate 2P and 2D shells undergo splitting, and the energy levels of 2Pz and 2Dz2 orbitals become higher than those of (2Px, 2Py) and (2Dxy,2Dyz,2Dxz,2Dx2-y2), resp. Therefore, stability of the most stable Si12Cr and Si12Fe clusters is attributed to the filling of the 2S22P62D8 and 2S22P62D10 closed shells.
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452Hou, L.; Yang, J.; Liu, Y. Reexamination of structures, stabilities, and electronic properties of holmium-doped silicon clusters HoSin (n = 12–20). J. Mol. Model. 2016, 22, 193, DOI: 10.1007/s00894-016-3058-1452https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2s3lslyrtQ%253D%253D&md5=48aeb265a2d5d86b42e7743070a03817Reexamination of structures, stabilities, and electronic properties of holmium-doped silicon clusters HoSi n (n = 12-20)Hou Liyuan; Yang Jucai; Yang Jucai; Liu YumingJournal of molecular modeling (2016), 22 (8), 193 ISSN:.The total energies, growth patterns, equilibrium geometries, relative stabilities, hardnesses, intramolecular charge transfer, and magnetic moments of HoSi n (n = 12-20) clusters have been reexamined theoretically using two different density functional schemes in combination with relativistic small-core Stuttgart effective core potentials (ECP28MWB) for the Ho atoms. The results show that when n = 12-15, the most stable structures are predicted to be exohedral frameworks with a quartet ground state, but when n = 16-20, they are predicted to be endohedral frameworks with a sextuplet ground state. These trend in stability across the clusters (gauged from their dissociation energies) was found to be approximately the same regardless of the DFT scheme used in the calculations, with HoSi13, HoSi16, HoSi18, and HoSi20 calculated to be more stable than the other clusters. The results obtained for cluster hardness indicated that doping the Ho atom into Si13 and Si16 leads to the most stable HoSi n clusters, while doping Ho into the other Si n clusters increases the photochemical sensitivity of the cluster. Analyses of intracluster charge transfer and magnetic moments revealed that charge always shifts from the Ho atom to the Si n cluster during the creation of exohedral HoSi n (n = 12-15) structures. However, the direction of charge transfer is reversed during the creation of endohedral HoSi n (n = 16-20) structures, which implies that Ho acts as an electron acceptor when it is encapsulated in the Si n cage. Furthermore, when the most stable exohedral HoSi n (n = 12-15) structures are generated, the 4f electrons of Ho are virtually unchanged and barely participate in intracluster bonding. However, in the most stable endohedral HoSi n (n = 16-20) frameworks, a 4f electron does participate in bonding. It does this by transferring to the 5d orbital, which hybridizes with the 6s and 6p orbitals and then interacts with Si valence sp orbitals. Meanwhile, the total magnetic moments of the HoSi n (n = 16-20) clusters are considerably higher than those of HoSi n (n = 12-15). Interestingly, the endohedral HoSi16 and HoSi20 clusters can be viewed as the most suitable building blocks for novel high-density magnetic storage nanomaterials and for novel optical and optoelectronic photosensitive nanomaterials, respectively.
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453Lu, S.-J.; Cao, G.-J.; Xu, X.-L.; Xu, H.-G.; Zheng, W.-J. The structural and electronic properties of NbSin–/0 (n = 3–12) clusters: Anion photoelectron spectroscopy and ab initio calculations. Nanoscale 2016, 8, 19769– 19778, DOI: 10.1039/C6NR07480D453https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVWmtrjL&md5=455af6389689e9328f8bc9773f5775fcThe structural and electronic properties of NbSin-/0 (n = 3-12) clusters: anion photoelectron spectroscopy and ab initio calculationsLu, Sheng-Jie; Cao, Guo-Jin; Xu, Xi-Ling; Xu, Hong-Guang; Zheng, Wei-JunNanoscale (2016), 8 (47), 19769-19778CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Niobium-doped silicon clusters, NbSin- (n = 3-12), were generated by laser vaporization and investigated by anion photoelectron spectroscopy. The structures and electronic properties of NbSin- anions and their neutral counterparts were investigated with ab initio calcns. and compared with the exptl. results. It is found that the Nb atom in NbSin-/0 prefers to occupy the high coordination sites to form more Nb-Si bonds. The most stable structures of NbSi3-7-/0 are all exohedral structures with the Nb atom face-capping the Sin frameworks. At n = 8, both the anion and neutral adopt a boat-shaped structure and the openings of the boat-shaped structures remain unclosed in NbSi9-10-/0 clusters. The most stable structure of the NbSi11- anion is endohedral, while that of neutral NbSi11 is exohedral. The global min. of both the NbSi12- anion and neutral NbSi12 are D6h sym. hexagonal prisms with the Nb atom at the center. The perfect D6h sym. hexagonal prism of NbSi12- is electronically stable as it obeys the 18-electron rule and has a shell-closed electronic structure with a large HOMO-LUMO gap of 2.70 eV. The MO anal. of NbSi12- suggests that the delocalized Nb-Si12 ligand interactions may contribute to the stability of the D6h sym. hexagonal prism. The AdNDP anal. shows that the delocalized 2c-2e Si-Si bonds and multicenter-2e NbSin bonds are important for the structural stability of the NbSi12- anion.
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454Lu, S.-J.; Xu, X.-L.; Feng, G.; Xu, H.-G.; Zheng, W.-J. Structural and electronic properties of AuSin– (n = 4–12) clusters: Photoelectron spectroscopy and ab initio calculations. J. Phys. Chem. C 2016, 120, 25628– 25637, DOI: 10.1021/acs.jpcc.6b08598454https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1ylurfO&md5=9982875b6c75e822369800a01032db2eStructural and Electronic Properties of AuSin- (n = 4-12) Clusters: Photoelectron Spectroscopy and Ab Initio CalculationsLu, Sheng-Jie; Xu, Xi-Ling; Feng, Gang; Xu, Hong-Guang; Zheng, Wei-JunJournal of Physical Chemistry C (2016), 120 (44), 25628-25637CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)AuSin- (n = 4-12) clusters were produced with a laser vaporization source and investigated by photoelectron spectroscopy. The swarm-intelligence-based CALYPSO structure search method and ab initio DFT-B3LYP calcns. were employed to det. their ground-state structures. The results revealed that the most stable isomers of AuSin- (n = 4-12) cluster anions are all exohedral structures, in which the Au atom caps the vertex, edge, or surface of the bare Sin clusters. The endohedral and exohedral structures of neutral AuSi11 are nearly degenerate in energy. The most stable structure of neutral AuSi12 is endohedral. The growth mechanism of AuSin- cluster anions is compared with those of AuGen-, AgSin-, and CuSin- clusters. It implies that the bond strengths of Au-Si and Au-Ge play important roles in the formation of cage structures for AuSi12- and AuGe12-, while the different at. radii of coinage metals, different bond strengths, and the strong relativistic effect in Au atom are responsible for the different growth mechanisms of Si clusters doped with different coinage metals.
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455Feng, Y.; Yang, J. Stability and electronic properties of praseodymium-doped silicon clusters PrSin (n = 12–21). J. Mol. Model. 2017, 23, 180, DOI: 10.1007/s00894-017-3352-6455https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1crltlClug%253D%253D&md5=ded7d3450b7a7b5416af962b9a1f0c43Stability and electronic properties of praseodymium-doped silicon clusters PrSin (n = 12-21)Feng Yutong; Yang JucaiJournal of molecular modeling (2017), 23 (6), 180 ISSN:.The neutral PrSi n (n = 12-21) species considering various spin configurations were systematically studied using PBE0 and B3LYP schemes in combination with relativistic small-core potentials (ECP28MWB) for Pr atoms and cc-pVTZ basis set for Si atoms. The total energy, growth-pattern, equilibrium geometry, relative stability, hardness, charge transfer, and magnetic moments are calculated and discussed. The results reveal that when n < 20, the ground-state structure of PrSi n evaluated to be prolate clusters. Starting from n = 20, the ground-state structures of PrSi n are evaluated to be endohedral cagelike clusters. Although the relative stabilities based on various binding energies and different functional is different from each other, the consensus is that the PrSi13, PrSi16, PrSi18, and PrSi20 are more stable than the others, especially the PrSi20. Analyses of hardness show that introducing Pr into Si n (n = 12-21) elevates the photochemical sensitivity, especially for PrSi20. Calculated result of magnetic moment and charge transfer shows that the 4f electrons of Pr in the clusters are changed, especially in endohedral structures such as PrSi20, in which one electron transfers from 4f to 5d orbital. That is, the 4f electron of Pr in the clusters participates in bonding. The way to participate in bonding is that a 4f electron transfers to 5d orbital. Although the 4f electron of Pr atom participates in bonding, the total magnetic moment of PrSi n is equal to that of isolated Pr atom. The charge always transfers from Pr atom to Si n cluster for the ground state structures of PrSin (n = 12-19), but charge transfer is reverse for n ≥ 20. The largest charge transfer for endohedral structure reveals that the bonding between Pr and Si n is ionic in nature and very strong. The fullerenelike structure of PrSi20 is the most stable among all of these clusters and can act as the building blocks for novel functional nanotubes.
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456Jin, X.; Arcisauskaite, V.; McGrady, J. E. The structural landscape in 14-vertex clusters of silicon, M@Si14: When two bonding paradigms collide. Dalton Trans. 2017, 46, 11636– 11644, DOI: 10.1039/C7DT02257C456https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1yns7zL&md5=92a7ef20ad80819831be090e377bca10The structural landscape in 14-vertex clusters of silicon, M@Si14: when two bonding paradigms collideJin, Xiao; Arcisauskaite, Vaida; McGrady, John E.Dalton Transactions (2017), 46 (35), 11636-11644CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)The structural chem. of the title clusters has been the source of controversy in the computational literature because the identity of the most stable structure appears to be pathol. dependent on the chosen theor. model. The candidate structures include a D3h-sym. 'fullerene-like' isomer with 3-connected vertices (A), an 'arachno' architecture (B) and an octahedral isomer with high vertex connectivities typical of 'closo' electron-deficient clusters (C). The key to understanding these apparently very different structures is the fact that they make use of the limited electron d. available from the endohedral metal in very different ways. Early in the transition series the favored structure is the one that maximizes transfer of electron d. from the electropos. metal to the cage whereas for later metals it is the one that minimizes repulsions with the increasingly core-like d electrons. The varying role of the d electrons across the transition series leads directly to strong functional dependency, and hence to the controversy in the literature.
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457Zhao, R.-N.; Chen, R.; Lu, Z.-C.; Han, J.-G. Geometrical and electronic properties of nanosize semiconductor Pt2Sin (n = 10–20) material: A density functional theory investigation. Mater. Sci. Eng., B 2017, 226, 151– 157, DOI: 10.1016/j.mseb.2017.09.011457https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFCqsb3O&md5=be70481b24b749caeb4adb28207967e8Geometrical and electronic properties of nanosize semiconductor Pt2Sin (n = 10-20) material: A density functional theory investigationZhao, Run-Ning; Chen, Rui; Lu, Zi-Chen; Han, Ju-GuangMaterials Science & Engineering, B: Advanced Functional Solid-State Materials (2017), 226 (), 151-157CODEN: MSBTEK; ISSN:0921-5107. (Elsevier B.V.)Growth-pattern behaviors, relative stabilities, geometrical and electronic properties of nanosize Pt2Sin (n = 10-20) semiconductor material are investigated by using d. functional methods. Optimized geometries exhibit that transition metal Pt2 is doped on small-size opened cage-like silicon frame with n = 10-15 while Pt2 is encapsulated into close cage-like Si frame with n = 16-20; Based upon the calcd. relative stabilities, the particular stable Pt2Si16 unit is discovered. Furthermore, the dominant growth patterns of Pt2Sin (n = 10-20) are based upon the stable pentagonal prism PtSi10 unit. Interestingly, the crit. size of geometry transition with bimetal atoms being completely encapsulated into silicon frame is detd. to be 15. The calcd. natural population anal. shows that charges are transferred from Sin frames to Pt2 atoms. Addnl., Pt2Si19 cluster has the smallest HOMO-LUMO gap and the strongest chem. activity.
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458Liu, Y.; Yang, J.; Cheng, L. Structural stability and evolution of scandium-doped silicon clusters: Evolution of linked to encapsulated structures and its influence on the prediction of electron affinities for ScSin (n = 4–16) clusters. Inorg. Chem. 2018, 57, 12934– 12940, DOI: 10.1021/acs.inorgchem.8b02159458https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVSqtbnF&md5=ef420a6ef605d178d23484be09405231Structural Stability and Evolution of Scandium-Doped Silicon Clusters: Evolution of Linked to Encapsulated Structures and Its Influence on the Prediction of Electron Affinities for ScSin (n = 4-16) ClustersLiu, Yuming; Yang, Jucai; Cheng, LinInorganic Chemistry (2018), 57 (20), 12934-12940CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Sc-doped semiconductor clusters are the simplest transition metal- and rare-earth metal-doped semiconductor clusters. In this work, the structural evolution behavior and electronic properties of Sc-doped neutral and anionic Sin (n = 4-16) clusters were studied using the ABCluster global search technique coupled with a hybrid d. functional method. The results revealed that although neutral and anionic configurations are different for ScSin (n = 6-14) clusters, the evolution pattern of the ground-state structures is consistent (evolution of linked to encapsulated structures starting from n = 14). The good agreement between the theor. and exptl. photoelectron spectra demonstrated that the obtained anionic global min. structures are reasonable. The excellent agreement between the adiabatic electron affinities cor. by considering the structural correction factor and the exptl. data indicated that the structural correction factor is important for reproducing the exptl. data and that the obtained ground-state structures for the neutral ScSin clusters reported herein are reliable. The relative stability and chem. bonding anal. showed that the fully encapsulated ScSi16- cluster is a magic cluster with good thermodn. and chem. stability.
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459Bista, D.; Reber, A. C.; Chauhan, V.; Khanna, S. N. Electronic and magnetic properties of Fe2Sin (1 ≤ n ≤ 12)+/0/– clusters. Chem. Phys. Lett. 2018, 706, 113– 119, DOI: 10.1016/j.cplett.2018.05.079459https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtVyjsLrJ&md5=6d98ea3f581d0c227a83d121ad71db02Electronic and magnetic properties of Fe2Sin (1 ≤ n ≤ 12)+/0/- clustersBista, Dinesh; Reber, Arthur C.; Chauhan, Vikas; Khanna, Shiv N.Chemical Physics Letters (2018), 706 (), 113-119CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)First principles studies on the geometry, electronic structure and magnetic properties of neutral, cationic, and anionic Fe2Sin (1 ≤ n ≤ 12) have been performed to better understand magnetic dopants in silicon. The doubly-Fe doped clusters in the size range 1 ≤ n ≤ 12 are marked by finite spin moments at the Fe sites, and Fe2Si3, Fe2Si4, and Fe2Si7 are found to exhibit antiferromagnetic coupling. Fe2Si3 and Fe2Si12 are relatively stable. We find that short Fe-Fe bond distances correlate with ferromagnetic coupling due to the destabilization of antibonding orbitals between the iron sites, while longer Fe-Fe bond distances lead to nonbonding AOs that favor antiferromagnetic coupling.
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460Yang, B.; Xu, H.; Xu, X.; Zheng, W. Photoelectron spectroscopy and theoretical study of CrnSi15–n– (n = 1–3): Effects of doping Cr atoms on the structural and magnetic properties. J. Phys. Chem. A 2018, 122, 9886– 9893, DOI: 10.1021/acs.jpca.8b10588460https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlylt7rO&md5=5138f3745330c6e6139245064d061a53Photoelectron Spectroscopy and Theoretical Study of CrnSi15-n- (n = 1-3): Effects of Doping Cr Atoms on the Structural and Magnetic PropertiesYang, Bin; Xu, Hongguang; Xu, Xiling; Zheng, WeijunJournal of Physical Chemistry A (2018), 122 (51), 9886-9893CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)CrnSi15-n- (n = 1-3) clusters were investigated by using size-selected anion photoelectron spectroscopy combined with d. functional theory calcns. The results show that the most stable structure of CrSi14- is of C2v symmetry with the Cr atom encapsulated in a Si14 cage which can be viewed as a boat-shaped Si10 unit capped by four addnl. silicon atoms. A large HOMO-LUMO gap of neutral CrSi14 is confirmed based on the photoelectron spectrum of CrSi14- anion. Cr2Si13- has two isomers nearly degenerate in energy: one can be characterized as one Si atom interacting with a Cr2Si12 hexagonal prism while the other can be viewed as one Si atom capping a distorted Cr2Si12 hexagonal antiprism. Cr3Si12- has a D6d sym. wheel structure in which three Cr atoms form an axle surrounded by 12 Si atoms. The magnetic moments of CrSi14-, Cr2Si13-, and Cr3Si12- increase from 1 to 3μB and then to 7μB with the increasing no. of Cr atoms in the clusters. The magnetic moments of Cr2Si13- and Cr3Si12- are mainly contributed by the surface Cr atoms.
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461Wu, X.; Zhou, S.; Huang, X.; Chen, M.; Bruce King, R.; Zhao, J. Revisit of large-gap Si16 clusters encapsulating group-IV metal atoms (Ti, Zr, Hf). J. Comput. Chem. 2018, 39, 2268– 2272, DOI: 10.1002/jcc.25545461https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhslWju7vP&md5=8c3a547f0adda9d697e851e31218143fRevisit of large-gap Si16 clusters encapsulating group-IV metal atoms (Ti, Zr, Hf)Wu, Xue; Zhou, Si; Huang, Xiaoming; Chen, Maodu; Bruce King, R.; Zhao, JijunJournal of Computational Chemistry (2018), 39 (27), 2268-2272CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)Doped clusters by Si16 cage encapsulating group-IV metal atoms (M@Si16, M = Ti, Zr and Hf) are computationally investigated by both d. functional theory (DFT) and high-level CCSD(T) method. Their low-energy structures are globally searched using a genetic algorithm based on DFT. The ground state structures of neutral and anionic M@Si16 are detd. by calcg. the vertical and adiabatic detachment energies and comparing them with the exptl. data. For neutral Ti@Si16, the Frank-Kasper (FK) deltahedron with Td symmetry and distorted FK isomer with C3v symmetry are nearly degenerate as the ground state and may coexist in lab., while the distorted FK isomer is the most probable structure for Ti@Si16- anion. For neutral and anionic Zr@Si16 and Hf@Si16 clusters, the ground states at finite temps. up to 300 K are the fullerene-like D4d bitruncated square trapezohedron. These theor. results establish a more complete picture for the most stable structures of M@Si16 clusters, which possess large gaps and may serve as building blocks for electronic and optoelectronic applications.
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462Lu, S.-J.; Wu, L.-S.; Lin, F. Probing the structures and properties of Ti2Si20–/0 clusters by density functional theory calculations. Chem. Phys. Lett. 2018, 707, 108– 112, DOI: 10.1016/j.cplett.2018.07.048462https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsVSms7vK&md5=6ecaae956c4137f9aa1033a952c4f6b8Probing the structures and properties of Ti2Si-/020 clusters by density functional theory calculationsLu, Sheng-Jie; Wu, Li-Shun; Lin, FengChemical Physics Letters (2018), 707 (), 108-112CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We present a theor. investigation on the structures and properties of Ti2Si-/020 clusters using d. functional theory calcns. The results showed that the global min. of both anionic and neutral Ti2Si20 adopt a C2h sym. double hexagonal prisms stacked structure with the two Ti atoms encapsulated inside the silicon cage. Bond length, Wiberg bond order, const. electronic charge d., and MO analyses suggest that the Ti-Ti interactions in Ti2Si-/020 are weak. Interestingly, Ti2Si-/020 exhibit significant 3D aromaticity, which play important roles in their structural stability.
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463Lu, S.-J. Exploring the structural evolution and electronic properties of medium-sized Nb2Sin–/0 (n= 13–20) clusters by density functional theory calculations. Chem. Phys. Lett. 2018, 713, 58– 64, DOI: 10.1016/j.cplett.2018.10.028463https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvFWqu73F&md5=06f95ebc604b34247dfa9583d222f6a5Exploring the structural evolution and electronic properties of medium-sized Nb2Sin-/0 (n = 13-20) clusters by density functional theory calculationsLu, Sheng-JieChemical Physics Letters (2018), 713 (), 58-64CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We present a theor. investigation on the structural evolution and electronic properties of Nb2Sin-/0 (n = 13-20) clusters. The two Nb atoms tend to stay close and occupy the high coordination sites. Their most stable structures can be described as a central axis of Nb-Nb bond surrounded by the Sin frameworks. The structural evolution between Nb2Sin- anions and Nb2Sin neutrals is markedly different. Nb2Si19- is found to be the crit. size of forming Nb2-endohedral structure for anionic clusters, whereas the Nb2-endohedral structure forms at n = 20 for neutral clusters.
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464Lu, S.-J.; Wu, L.-S.; Lin, F. Probing the geometric structures and bonding properties in Nb2Si20–/0 clusters by density functional theory calculations. Chem. Phys. Lett. 2018, 709, 60– 64, DOI: 10.1016/j.cplett.2018.08.041464https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsF2gsbvO&md5=de58ada367efab737dc9ad9a028fb47dProbing the geometric structures and bonding properties in Nb2Si-/020 clusters by density functional theory calculationsLu, Sheng-Jie; Wu, Li-Shun; Lin, FengChemical Physics Letters (2018), 709 (), 60-64CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We present a theor. investigation on the geometric structures and bonding properties of Nb2Si20-/0 clusters using d. functional theory calcns. The results showed that Nb2Si20- anion has an irregular Nb2-doped endohedral structure, whereas Nb2Si20 neutral adopts C2h sym. elongated dodecahedron cage structure, which is composed of twelve pentagonal faces. Bond length, Wiberg bond order, const. electronic charge d., and MO analyses suggest that the Nb-Nb interactions in Nb2Si20-/0 are strong. Interestingly, Nb2Si20-/0 exhibit significant 3D aromaticity.
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465Lu, S.-J. Exploring the structural and electronic properties of double-Fe atom-doped Si20 cluster by quantum chemical calculations. Theor. Chem. Acc. 2019, 138, 48, DOI: 10.1007/s00214-019-2438-xThere is no corresponding record for this reference.
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466Yang, B.; Xu, X.-L.; Xu, H.-G.; Farooq, U.; Zheng, W.-J. Structural evolution and electronic properties of CoSin– (n = 3–12) clusters: Mass-selected anion photoelectron spectroscopy and quantum chemistry calculations. Phys. Chem. Chem. Phys. 2019, 21, 6207– 6215, DOI: 10.1039/C8CP07734G466https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXjtlWgur4%253D&md5=c934f8dcdefd6ceac7a5c641c8569ed3Structural evolution and electronic properties of CoSin- (n = 3-12) clusters: mass-selected anion photoelectron spectroscopy and quantum chemistry calculationsYang, Bin; Xu, Xi-Ling; Xu, Hong-Guang; Farooq, Umar; Zheng, Wei-JunPhysical Chemistry Chemical Physics (2019), 21 (11), 6207-6215CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structural and electronic properties of cobalt-doped silicon clusters, CoSin- (n = 3-12), are investigated using mass-selected anion photoelectron spectroscopy combined with quantum chem. calcns. The crit. size from an exohedral to an endohedral structure of the anionic clusters is n = 9 and that of the neutral ones is n = 10. Natural population anal. shows transfer of electrons from the silicon framework to the Co atom. The total magnetic moments of CoSi3- and CoSi4- clusters are 2μB, while those of CoSin- (n = 5-12) clusters are 0μB. The exptl. measurements show that CoSi10- has the highest vertical detachment energy among all the CoSin- (n = 3-12) clusters in the current study. The theor. calcns. show that CoSi10- has a C3v sym. tetracapped trigonal prism structure and very large HOMO-LUMO gap. Both exptl. and theor. results imply that CoSi10- has unusual stability. Its special stability is attributed to its highly sym. structure and closed-shell MO configuration. The structure of neutral CoSi10 has relatively lower symmetry as compared to that of CoSi10- due to Jahn-Teller distortion.
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467Majumder, C.; Kulshreshtha, S. Impurity-doped Si10 cluster: Understanding the structural and electronic properties from first-principles calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 245426, DOI: 10.1103/PhysRevB.70.245426467https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXislOlug%253D%253D&md5=c0629e5e81430a526851dc786cfa3021Impurity-doped Si10 cluster: understanding the structural and electronic properties from first-principles calculationsMajumder, Chiranjib; Kulshreshtha, S. K.Physical Review B: Condensed Matter and Materials Physics (2004), 70 (24), 245426/1-245426/7CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Structural and electronic properties of metal-doped silicon clusters (MSi10, M = Li, Be, B, C, Na, Mg, Al, and Si) have been investigated via ab initio mol. dynamics simulation under the formalism of the d. functional theory. The exchange-correlation energy has been calcd. using the generalized gradient approxn. method. Several stable isomers of MSi10 clusters have been identified based on different initial configurations and their relative stabilities have been analyzed. The location of the impurity atom depends on the nature of interaction between the impurity atom and the host cluster and the size of the impurity atom. Whereas Be and B atoms form stable isomers, the impurity atom being placed at the center of the bicapped tetragonal antiprism structure of the Si10 cluster, all other elements diffuse outside the cage of Si10 cluster. To understand the stability and the chem. bonding, the LCAO-MO based all electron calcns. have been carried out for the lowest energy isomers using the hybrid B3LYP energy functional. Based on the interaction energy of the M atoms with Si10 clusters it is found that p-p interaction dominates over the s-p interaction and smaller size atoms interact more strongly. Based on the binding energy, the relative stability of MSi10 clusters is found to follow the order of CSi10 > BSi10 > BeSi10 > Si11 > AlSi10 > LiSi10 > NaSi10 > MgSi10, leading one to infer that while the substitution of C, B and Be enhances the stability of the Si11 cluster, others have an opposite effect. The extra stability of the BeSi10 clusters is due to its encapsulated close packed structure and large energy gap between the HOMO and LUMO energy levels.
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468Sporea, C.; Rabilloud, F. Stability of alkali-encapsulating silicon cage clusters. J. Chem. Phys. 2007, 127, 164306, DOI: 10.1063/1.2790018468https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXht12jsLjN&md5=b83b9112801e558709e6a534e3449910Stability of alkali-encapsulating silicon cage clustersSporea, C.; Rabilloud, F.Journal of Chemical Physics (2007), 127 (16), 164306/1-164306/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report a DFT-B3LYP computational study of the possibility to form alkali-encapsulating Si clusters A@Sin with n = 10-20. We predict and quantify the stability for lithium, sodium, and potassium atoms encapsulated in silicon cage. The structure and electronic properties are discussed. An electronic charge transfer from the alkali atom to the Sin cage is obsd. The A@Sin cluster is formed of a pos. charge located on the alkali surrounded by a neg. one distributed on the whole Si cage. For each size the predicted stability of such structure is discussed and compared with that of surface-bound alkali isomers. The alkali-encapsulating Si clusters A@Sin are found to be stable but lying much higher in energy as compared to surface-bound alkali isomers.
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469Hossain, D.; Hagelberg, F.; Pittman, C. U.; Saebo, S. Structures and stabilities of clusters of Si12, Si18, and Si20 containing endohedral charged and neutral atomic species. J. Phys. Chem. C 2007, 111, 13864– 13871, DOI: 10.1021/jp0735839469https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXpsFyhsbY%253D&md5=91b663136b1cc58ff59be99e29e8d663Structures and Stabilities of Clusters of Si12, Si18, and Si20 Containing Endohedral Charged and Neutral Atomic SpeciesHossain, Delwar; Hagelberg, Frank; Pittman, Charles U., Jr.; Saebo, SveinJournal of Physical Chemistry C (2007), 111 (37), 13864-13871CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Electronic structure calcns. based on DFT-B3LYP and MP2 methods were performed on three isomers of Si12 and on the endohedral clusters Si12 contg. neutral or charged at. species. The existence of endohedral clusters depends on the Si12 cage shape and the nature of the embedding species. Endohedral clusters of Li0,1,-1, Na0,1,-1, and He in Si12 cages were found. In contrast, K+, Ne, F-, or Cl- do not form endohedral clusters with Si12 due to their large size. All endohedral clusters that are min. on the potential energy surfaces are stable and have large HOMO-LUMO gaps ( > 1 eV). The stability order for the lithium and sodium clusters is: anionic clusters > neutral clusters > cationic clusters. The endohedral complex of two Li atoms with the Si18 cage is lower in energy than the sum of the empty Si18 cage and two Li atoms. In contrast, doping two Na atoms into the Si18 cage forms an exohedral Na2Si18 cluster. An endohedral cluster of Li2 with Si20 was also investigated and characterized. The stability of the endohedral complexes of two Li atoms in Si18 and Si20 suggest that silicon nanotubes, which are unstable, might be stabilized by an internal string of Li atoms.
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470Avaltroni, F.; Steinmann, S. N.; Corminboeuf, C. How are small endohedral silicon clusters stabilized?. Phys. Chem. Chem. Phys. 2012, 14, 14842– 14849, DOI: 10.1039/c2cp42097j470https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFersrrK&md5=ed91d06eb503e9d5d616ecda05ef271bHow are small endohedral silicon clusters stabilized?Avaltroni, Fabrice; Steinmann, Stephan N.; Corminboeuf, ClemencePhysical Chemistry Chemical Physics (2012), 14 (43), 14842-14849CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Clusters in the (Be, B, C)@Sin(0,1,2+) (n = 6-10) series, isoelectronic to Sin2-, present multiple sym. structures, including rings, cages and open structures, which the doping atom stabilizes using contrasting bonding mechanisms. The most striking feature of these clusters is the absence of electron transfer (for Be) or even the inversion (for B and C) in comparison to classic endohedral metallofullerenes (e.g. from the outer frameworks towards the enclosed atom). The relatively small cavity of the highly sym. Si8 cubic cage benefits more strongly from the encapsulation of a boron atom than from the insertion of a too large beryllium atom. Overall, the maximization of multicenter-type bonding, as visualized by the Localized Orbital Locator (LOL), is the key to the stabilization of the small Sin cages. Boron offers the best balance between size, electronegativity and delocalized bonding pattern when compared to beryllium and carbon.
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471Lu, S.-J.; Xu, X.-L.; Cao, G.-J.; Xu, H.-G.; Zheng, W.-J. Structural evolution of B2Sin–/0 (n = 3–12) clusters: Size-selected anion photoelectron spectroscopy and theoretical calculations. J. Phys. Chem. C 2018, 122, 2391– 2401, DOI: 10.1021/acs.jpcc.7b10906471https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjsVKhug%253D%253D&md5=40a504c850fc6c04700c805e43e1236eStructural Evolution of B2Sin-/0 (n = 3-12) Clusters: Size-Selected Anion Photoelectron Spectroscopy and Theoretical CalculationsLu, Sheng-Jie; Xu, Xi-Ling; Cao, Guo-Jin; Xu, Hong-Guang; Zheng, Wei-JunJournal of Physical Chemistry C (2018), 122 (4), 2391-2401CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structural evolution of B2Sin-/0 (n = 3-12) clusters were studied by anion photoelectron spectroscopy and ab initio calcns. The 2 B atoms in B2Si3-12-/0 incline to form a B-B bond and more B-Si bonds. The lowest-lying isomers of B2Si3-/0 have planar structures, while those of B2Si4-7-/0 primarily adopt bowl-shaped based geometries. The 2 B atoms in B2Si8-9-/0 are not completely encapsulated into the Sin cages. For B2Si10-/0, the 2 B atoms are completely encapsulated inside the Si10 cage to form a distorted pentagonal prismatic structure. B2Si10-/0 exhibits 3D aromaticity and B2Si10 neutral has σ + π double delocalized bonding patterns. B2Si11- anion has an endohedral polyhedral cage-like structure, whereas B2Si11 neutral adopts a bicapped pentagonal prismatic structure with only one interior B atom. The structures of anionic and neutral B2Si12 are endohedral tetracapped tetragonal prisms. It is interesting that 2 Si5 5-membered rings are stabilized by 2 B atoms in B2Si10-/0, while the stabilization of 2 Si6 6-membered rings by 2 B atoms is not obsd. in B2Si12-/0.
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472Borshch, N.; Berestnev, K.; Pereslavtseva, N.; Kurganskii, S. Geometric structure and electron spectrum of YSin– clusters (n = 6–17). Phys. Solid State 2014, 56, 1276– 1281, DOI: 10.1134/S1063783414060080472https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXpvFGqur4%253D&md5=1181d59a28af085fb0ecb69db6f37123Geometric structure and electron spectrum of YSi-n clusters (n = 6-17)Borshch, N. A.; Berestnev, K. S.; Pereslavtseva, N. S.; Kurganskii, S. I.Physics of the Solid State (2014), 56 (6), 1276-1281CODEN: PSOSED; ISSN:1063-7834. (SP MAIK Nauka/Interperiodica)Results of the optimization of the geometric structure of YSi-n anion clusters (n = 6-17) have been presented and their electron spectra have been calcd. Calcns. have been performed by the d. functional theory method. Actual geometric structures of clusters have been established by comparing the calcd. and known exptl. data.
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473Trivedi, R.; Bandyopadhyay, D. Evolution of electronic and vibrational properties of M@Xn (M = Ag, Au, X = Ge, Si, n = 10, 12, 14) clusters: A density functional modeling. J. Mater. Sci. 2018, 53, 8263– 8273, DOI: 10.1007/s10853-018-2002-4473https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjvVOmurk%253D&md5=cfd4e33c0bf4b24d44f343b5c8834542Evolution of electronic and vibrational properties of M@Xn (M = Ag, Au, X = Ge, Si, n = 10, 12, 14) clusters: a density functional modelingTrivedi, Ravi; Bandyopadhyay, DebashisJournal of Materials Science (2018), 53 (11), 8263-8273CODEN: JMTSAS; ISSN:0022-2461. (Springer)Evolution of electronic and vibrational properties of M@Xn (M = Ag, Au, X = Ge, Si, n = 10, 12, 14) nanoclusters is investigated by using first-principle d. functional theory (DFT)-based calcns. with effective core potentials. To explain the thermodn. and chem. stability of the ground state cluster in each size, variation of different thermodn. and chem. parameters, like, binding energy (BE), HOMO-LUMO gap (ΔE), vertical ionization potential (VIP) and vertical electron affinity (VEA) was studied with the variation of the size of the clusters for emphasizing the differences and similarities in the clusters. It is found that Au doping in Ge and Si cages prefers endohedral position, whereas Ag prefers to take the position at the surface of the cages. In addn., IR and Raman spectra of the clusters are also studied to understand the vibrational nature of the stable clusters. At the end, present theor. results are compared with existing exptl. data. Theor. knowledge of the thermodn., chem. and vibrational properties of these specific ground state structures is important for understanding its potential application in the field of optoelectronic science.
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474Ngan, V. T.; Pierloot, K.; Nguyen, M. T. Mn@Si14+: A singlet fullerene-like endohedrally doped silicon cluster. Phys. Chem. Chem. Phys. 2013, 15, 5493– 5498, DOI: 10.1039/c3cp43390k474https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXkt1GgtLs%253D&md5=2917f3d717838e3c769e3b76f809c62cMn@Si14+: a singlet fullerene-like endohedrally doped silicon clusterNgan, Vu Thi; Pierloot, Kristine; Nguyen, Minh ThoPhysical Chemistry Chemical Physics (2013), 15 (15), 5493-5498CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The electronic structure of Mn@Si14+ is detd. using DFT and CASPT2/CASSCF(14,15) computations with large basis sets. The endohedrally Mn-doped Si cationic cluster has a D3h fullerene-like structure featuring a closed-shell singlet ground state with a singlet-triplet gap of ∼1 eV. A strong stabilizing interaction occurs between the 3d(Mn) and the 2D-shell(Si14) orbitals, and a large amt. of charge is transferred from the Si14 cage to the Mn dopant. The 3d(Mn) orbitals are filled by encapsulation, and the magnetic moment of Mn is completely quenched. Full occupation of [2S, 2P, 2D] shell orbitals by 18 delocalized electrons confers the doped Mn@Si14+ cluster a spherically arom. character.
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475Li, Y.; Tam, N. M.; Woodham, A. P.; Lyon, J. T.; Li, Z.; Lievens, P.; Fielicke, A.; Nguyen, M. T.; Janssens, E. Structure dependent magnetic coupling in cobalt-doped silicon clusters. J. Phys. Chem. C 2016, 120, 19454– 19460, DOI: 10.1021/acs.jpcc.6b06320475https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht12jsLjF&md5=d6903790e6be51602e2454e41a41bd56Structure Dependent Magnetic Coupling in Cobalt-Doped Silicon ClustersLi, Yejun; Tam, Nguyen Minh; Woodham, Alex P.; Lyon, Jonathan T.; Li, Zhe; Lievens, Peter; Fielicke, Andre; Nguyen, Minh Tho; Janssens, EwaldJournal of Physical Chemistry C (2016), 120 (34), 19454-19460CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structure of cobalt-doped silicon clusters, SinCo+ (n = 5-8) and SinCo2+ (n = 8-12), is investigated in a combined IR multiple photon dissocn. spectroscopy and d. functional theory study. The singly doped clusters have exohedral structures in which the Co atom substitutes an atom of bare Sin+1+ clusters. In the doubly doped SinCo2+ clusters, the second Co atom is adsorbed to the singly doped counterparts and, for n ≥ 9, one of the Co atoms is encapsulated by a silicon cage. Computational anal. of the electronic and magnetic properties of the identified isomers indicates a distance dependent magnetic coupling between the Co atoms in the SinCo2+ clusters.
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476Gao, Y.; Zeng, X. C. M4@Si28 (M = Al, Ga): Metal-encapsulated tetrahedral silicon fullerene. J. Chem. Phys. 2005, 123, 204325, DOI: 10.1063/1.2121568476https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtlGiu7%252FN&md5=51c4ca0336ac80a0ad6e073cd7f60a9bM4@Si28 (M = Al, Ga): Metal-encapsulated tetrahedral silicon fullereneGao, Yi; Zeng, X. C.Journal of Chemical Physics (2005), 123 (20), 204325/1-204325/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)It is known that silicon fullerenes cannot maintain perfect cage structures like carbon fullerenes. Previous d.-functional theory calcns. have shown that even with encapsulated species, nearly all endohedral silicon fullerenes exhibit highly puckered cage structures in comparison with their carbon counterparts. In this work, we present theor. evidences that the tetrahedral fullerene cage Si28 can be fully stabilized by encapsulating a tetrahedral metallic cluster (Al4 or Ga4). To our knowledge, this is the first predicted endohedral silicon fullerene that can retain perfectly the same cage structure (without puckering) as the carbon fullerene counterpart (Td-C28 fullerene). D.-functional theory calcns. also suggest that the two endohedral metallo-silicon fullerenes Td-M4@Si28 (M = Al and Ga) can be chem. stable because both clusters have a large HOMO-LUMO energy gap (∼0.9 eV), strong spherical aromaticity (nucleus-independent chem. shift value of -36 and -44), and large binding and embedding energies.
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477Hagelberg, F.; Yanov, I.; Leszczynski, J. Theoretical investigations on closed-shell silicon clusters doped with Cu atoms. J. Mol. Struct.: THEOCHEM 1999, 487, 183– 192, DOI: 10.1016/S0166-1280(99)00153-0477https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXlslelt7s%253D&md5=c89b488d5837f435c6e2b5869112686fTheoretical investigations on closed-shell silicon clusters doped with Cu atomsHagelberg, F.; Yanov, I.; Leszczynski, J.Journal of Molecular Structure: THEOCHEM (1999), 487 (1-2), 183-192CODEN: THEODJ; ISSN:0166-1280. (Elsevier Science B.V.)Silicon clusters doped with a single Cu impurity (CuSin), which were detected previously by mass spectrometric expt., were explored by means of ab initio ROHF anal. Features related to geometries, stabilities and adsorption energies of the species CuSin, n = 4, 6, 8, 10, 12, 14, are discussed. The sensitive dependence of the phys. properties of CuSin clusters on the geometric arrangement of the resp. Sin subsystem is emphasized.
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478Pederson, M. R.; Jackson, K. A. Variational mesh for quantum-mechanical simulations. Phys. Rev. B: Condens. Matter Mater. Phys. 1990, 41, 7453– 7461, DOI: 10.1103/PhysRevB.41.7453478https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sfkvFyjtA%253D%253D&md5=5aa04fa8685ae5d3e40b350f850396d7Variational mesh for quantum-mechanical simulationsPederson; JacksonPhysical review. B, Condensed matter (1990), 41 (11), 7453-7461 ISSN:0163-1829.There is no expanded citation for this reference.
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479Porezag, D.; Pederson, M. R. Optimization of Gaussian basis sets for density-functional calculations. Phys. Rev. A: At., Mol., Opt. Phys. 1999, 60, 2840– 2847, DOI: 10.1103/PhysRevA.60.2840479https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmt1Ohs70%253D&md5=79c70934d1b43f39816b4ad83ddee42bOptimization of Gaussian basis sets for density-functional calculationsPorezag, Dirk; Pederson, Mark R.Physical Review A: Atomic, Molecular, and Optical Physics (1999), 60 (4), 2840-2847CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)We introduce a scheme for the optimization of Gaussian basis sets for use in d.-functional calcns. It is applicable to both all-electron and pseudopotential methodologies. In contrast to earlier approaches, the no. of primitive Gaussians (exponents) used to define the basis functions is not fixed but adjusted, based on a total-energy criterion. Furthermore, all basis functions share the same set of exponents. The numerical results for the scaling of the shortest-range Gaussian exponent as a function of the nuclear charge are explained by anal. derivations. We have generated all-electron basis sets for H, B through F, Al, Si, Mn, and Cu. They efficiently and accurately reproduce structural properties and binding energies for a variety of clusters and mols. for both local and gradient-cor. d. functionals.
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480Jaeger, J.; Jaeger, T.; Duncan, M. Photodissociation of metal–silicon clusters: Encapsulated versus surface-bound metal. J. Phys. Chem. A 2006, 110, 9310– 9314, DOI: 10.1021/jp0629947480https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmslGrs7Y%253D&md5=4e06d5e93ab1beeb94aa54aaa9ecd5b5Photodissociation of Metal-Silicon Clusters: Encapsulated versus Surface-Bound MetalJaeger, J. B.; Jaeger, T. D.; Duncan, M. A.Journal of Physical Chemistry A (2006), 110 (30), 9310-9314CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Metal-silicon cluster cations of the form MSin+ (M = Cu, Ag, Cr) are produced in a mol. beam with pulsed laser vaporization. These species are mass-selected in a reflectron time-of-flight spectrometer and studied with laser photodissocn. at 532 and 355 nm. For the noble metals copper and silver, photodissocn. of the n = 7 and 10 clusters proceeds primarily by the loss of metal atoms, indicating that the metal is not located within the interior of silicon cages, and that metal-silicon bonding is weaker than silicon-silicon bonding. Chromium-silicon clusters for n = 7 also lose primarily the metal atom, but at n = 15 and 16 these dissoc. via the loss of silicon, producing smaller metal-silicon species. This behavior is consistent with stronger metal-silicon bonding and encapsulated metal structures, as suggested previously by theory. MSi6+ cations are produced efficiently in all of these photodissocn. processes, indicating that these species have enhanced stability compared to other small clusters. Improved values are obtained for the ionization potentials of Si7 and Si10.
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481Negishi, A.; Kariya, N.; Sugawara, K.-i.; Arai, I.; Hiura, H.; Kanayama, T. Size-selective formation of tungsten cluster-containing silicon cages by the reactions of Wn+ (n = 1–5) with SiH4. Chem. Phys. Lett. 2004, 388, 463– 467, DOI: 10.1016/j.cplett.2004.03.036481https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjtVShsrg%253D&md5=786a3e4818cd5668e617542c44f9a3feSize-selective formation of tungsten cluster-containing silicon cages by the reactions of Wn+ (n = 1-5) with SiH4Negishi, Akihiro; Kariya, Naoki; Sugawara, Ko-ichi; Arai, Ichiro; Hiura, Hidefumi; Kanayama, ToshihikoChemical Physics Letters (2004), 388 (4-6), 463-467CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The reactions of tungsten clusters, W+n (n = 1-5), with silane and their sequential reactions were investigated using FTICR mass spectrometry. It was found that the Si or SiH2 addn. to the clusters, accompanied by H2 release, occurred for every collision with silane and then suddenly stopped at the specific silicon atom nos. of m: m = 12 for n = 1, m = 17 and 18 for n = 2, m = 22 for n = 3, m = 25 and 26 for n = 4 and m = 29 for n = 5. These values coincide with the surrounding atom nos. of a simple close packing model, suggesting the formation of stable silicon cages encapsulating tungsten clusters.
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482Kaneko, T.; Takaya, H.; Hatakeyama, R. Generation of argon-ion mixed silicon plasmas forming argon encapsulated silicon clusters. Appl. Phys. Lett. 2006, 89, 241501, DOI: 10.1063/1.2404606482https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXislGktg%253D%253D&md5=6d13e2633ba5189a43cb89ccab8ddfddGeneration of argon-ion mixed silicon plasmas forming argon encapsulated silicon clustersKaneko, T.; Takaya, H.; Hatakeyama, R.Applied Physics Letters (2006), 89 (24), 241501/1-241501/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)An inductively coupled argon (Ar) plasma is superimposed on a silicon (Si) plasma generated by an electron beam gun to realize the formation of gas-atom encapsulated Si cage clusters. The Si clusters, which are formed and deposited on a substrate, are analyzed by laser-desorption time-of-flight mass spectrometry and have the mass spectra of not only pure Si cluster (Sin; n = 1-17) but also Si cluster doped with Ar atom (ArSin; n = 10-20) in the case that the large amt. of Ar ions is generated in addn. to the Si plasma. Together with the anal. of XPS, the Ar atom is included in the Si cluster, forming the structure of endohedral Ar@Sin complexes. Also, the mass spectrum of Ar@Sin indicates the existence of the magic numbered cluster size n = 15, 16 similar to the metal encapsulated Si clusters.
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483Neukermans, S.; Wang, X.; Veldeman, N.; Janssens, E.; Silverans, R.; Lievens, P. Mass spectrometric stability study of binary MSn clusters (S = Si, Ge, Sn, Pb, and M = Cr, Mn, Cu, Zn). Int. J. Mass Spectrom. 2006, 252, 145– 150, DOI: 10.1016/j.ijms.2005.12.056483https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XktVygtbg%253D&md5=86163df1a62d249b6fd37e96e3a577e0Mass spectrometric stability study of binary MSn clusters (S=Si, Ge, Sn, Pb, and M=Cr, Mn, Cu, Zn)Neukermans, S.; Wang, X.; Veldeman, N.; Janssens, E.; Silverans, R. E.; Lievens, P.International Journal of Mass Spectrometry (2006), 252 (2), 145-150CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)The authors present a mass spectrometric stability study of metal doped Group IVA (semi-) metal clusters. Binary metal (M) doped semi-metal (S) MSn (S = Si, Ge, Sn, Pb, and M = Cr, Mn, Cu, Zn) clusters are produced using a dual-target, dual-laser vaporization source and mass analyzed using a reflectron time-of-flight mass spectrometer. The resulting abundance spectra reveal host and dopant dependent stability information for the different systems studied. From a comparison between the exptl. abundance information and computational studies available in literature, the enhanced abundance of several sizes is interpreted in terms of peculiarly stable dopant-encapsulated cagelike structures.
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484Janssens, E.; Gruene, P.; Meijer, G.; Wöste, L.; Lievens, P.; Fielicke, A. Argon physisorption as structural probe for endohedrally doped silicon clusters. Phys. Rev. Lett. 2007, 99, 063401, DOI: 10.1103/PhysRevLett.99.063401484https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXovFGrtLc%253D&md5=bc31e8ef470ac5fd73b74bb0b91b1778Argon Physisorption as Structural Probe for Endohedrally Doped Silicon ClustersJanssens, Ewald; Gruene, Philipp; Meijer, Gerard; Woste, Ludger; Lievens, Peter; Fielicke, AndrePhysical Review Letters (2007), 99 (6), 063401/1-063401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report on an element-dependent crit. size for argon physisorption at 80 K on transition-metal-doped silicon clusters. Argon does not attach to elemental silicon clusters but only to surface-located transition-metal atoms. Thus physisorption provides structural information. Specifically, the minimal cluster size for the formation of endohedral singly metal-doped silicon cages has been detd. The obsd. crit. size for doubly doped silicon clusters indicates that larger caged mols. can be formed, eventually leading to the growth of metal-doped silicon nanorods.
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485Ohara, M.; Miyajima, K.; Pramann, A.; Nakajima, A.; Kaya, K. Geometric and electronic structures of terbium–silicon mixed clusters (TbSin; 6 ≤ n ≤ 16). J. Phys. Chem. A 2002, 106, 3702– 3705, DOI: 10.1021/jp012952c485https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XhvVGrsb8%253D&md5=ab317874d4e2b8ad2c2f12393050a3f3Geometric and Electronic Structures of Terbium-Silicon Mixed Clusters (TbSin; 6 ≤ n ≤ 16)Ohara, M.; Miyajima, K.; Pramann, A.; Nakajima, A.; Kaya, K.Journal of Physical Chemistry A (2002), 106 (15), 3702-3705CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The geometric and the electronic structures of terbium-silicon anions, TbSin- (6 ≤ n ≤ 16) were investigated by using photoelectron spectroscopy (PES) and a chem.-probe method. The clusters were produced by a double-rod laser vaporization technique. From trends obsd. in the electron affinities (EAs), the TbSin- clusters were categorized into three groups of (I) 6 ≤ n ≤ 9, (II) n = 10, 11, and (III) n ≥ 12. Together with adsorption reactivity toward H2O it is concluded that a Tb atom is encapsulated inside a Sin cage at n ≥ 10; Tb@Sin.
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486Koyasu, K.; Atobe, J.; Akutsu, M.; Mitsui, M.; Nakajima, A. Electronic and geometric stabilities of clusters with transition metal encapsulated by silicon. J. Phys. Chem. A 2007, 111, 42– 49, DOI: 10.1021/jp066757f486https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlSgs7jN&md5=cb52754f7efb8dae369a13c27ecf6bf8Electronic and Geometric Stabilities of Clusters with Transition Metal Encapsulated by SiliconKoyasu, Kiichirou; Atobe, Junko; Akutsu, Minoru; Mitsui, Masaaki; Nakajima, AtsushiJournal of Physical Chemistry A (2007), 111 (1), 42-49CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Silicon clusters mixed with a transition metal atom, MSin, were generated by a double-laser vaporization method, and the electronic and geometric stabilities for the resulting clusters with transition metal encapsulated by silicon were examd. exptl. By means of a systematic doping with transition metal atoms of groups 3, 4, and 5 (M = Sc, Y, Lu, Ti, Zr, Hf, V, Nb, and Ta), followed by changes of charge states, we explored the use of an electronic closing of a silicon caged cluster and variations in its cavity size to facilitate metal-atom encapsulation. Results obtained by mass spectrometry, anion photoelectron spectroscopy, and adsorption reactivity toward H2O show that the neutral cluster doped with a group 4 atom features an electronic and a geometric closing at n = 16. The MSi16 cluster with a group 4 atom undergoes an electronic change in (i) the no. of valence electrons when the metal atom is substituted by the neighboring metals with a group 3 or 5 atom and in (ii) at. radii with the substitution of the same group elements of Zr and Hf. The reactivity of a halogen atom with the MSi16 clusters reveals that VSi16F forms a superatom complex with ionic bonding.
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487Koyasu, K.; Atobe, J.; Furuse, S.; Nakajima, A. Anion photoelectron spectroscopy of transition metal-and lanthanide metal-silicon clusters: MSin– (n= 6–20). J. Chem. Phys. 2008, 129, 214301, DOI: 10.1063/1.3023080487https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsVKqsr3P&md5=d72830880fc9e49d2f80ab73b85f679cAnion photoelectron spectroscopy of transition metal- and lanthanide metal-silicon clusters: MSin- (n = 6-20)Koyasu, Kiichirou; Atobe, Junko; Furuse, Shunsuke; Nakajima, AtsushiJournal of Chemical Physics (2008), 129 (21), 214301/1-214301/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic properties of Si clusters contg. a transition or lanthanide metal atom from Group 3, 4, or 5, MSin, (M = Sc, Ti, V, Y, Zr, Nb, Lu, Tb, Ho, Hf, and Ta) were studied by anion photoelectron spectroscopy at 213 nm. In the case of the group 3 elements Sc, Y, Lu, Tb, and Ho, the threshold energy of electron detachment exhibits local maxima at n = 10 and 16, while in case of the group 4 elements Ti, Zr, and Hf, the threshold energy exhibits a local min. at n = 16, assocd. with the presence of a small bump in the spectrum. These electronic characteristics of MSin are closely related to a cooperative effect between their geometric and electronic structures, which is discussed, together with the results of expts. that probe their geometric stability via their reactivity to H2O adsorption, and with theor. calcns. (c) 2008 American Institute of Physics.
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488Shibuta, M.; Ohta, T.; Nakaya, M.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Chemical characterization of an alkali-like superatom consisting of a Ta-encapsulating Si16 cage. J. Am. Chem. Soc. 2015, 137, 14015– 14018, DOI: 10.1021/jacs.5b08035488https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhslOrt77O&md5=a5a3521c93079e4ccc0de7aa88c0d065Chemical Characterization of an Alkali-Like Superatom Consisting of a Ta-Encapsulating Si16 CageShibuta, Masahiro; Ohta, Tsutomu; Nakaya, Masato; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiJournal of the American Chemical Society (2015), 137 (44), 14015-14018CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Chem. characterization was performed for an alkali-like superatom consisting of a Ta-encapsulating Si16 cage, Ta@Si16, deposited on a graphite substrate using XPS to element-specifically clarify the local electronic structure of the cage atoms. The XPS spectra derived from Ta 4f and Si 2p core levels were well modeled with a single chem. component, revealing the formation of a sym. Si cage around the Ta atom in the deposited nanoclusters. On chem. treatments by heating or O2 exposure, the deposited Ta@Si16 is thermally stable up to 700 K and is also exceptionally less reactive toward O2 compared to other Ta-Si nanoclusters, although some heat degrdn. and oxidn. accompany the treatments. These results show the promising possibility of applying Ta@Si16 as a building block to fabricate cluster-assembled materials consisting of naked nanoclusters.
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489Tsunoyama, H.; Shibuta, M.; Nakaya, M.; Eguchi, T.; Nakajima, A. Synthesis and characterization of metal-encapsulating Si16 cage superatoms. Acc. Chem. Res. 2018, 51, 1735– 1745, DOI: 10.1021/acs.accounts.8b00085489https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXosFKhsb8%253D&md5=2d2edfd1250704f9f9d473b293408cc9Synthesis and characterization of metal-encapsulating Si16 cage superatomsTsunoyama, Hironori; Shibuta, Masahiro; Nakaya, Masato; Eguchi, Toyoaki; Nakajima, AtsushiAccounts of Chemical Research (2018), 51 (8), 1735-1745CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)Nanoclusters, aggregates of several to hundreds of atoms, have been one of the central issues of nanomaterials sciences owing to their unique structures and properties, which could be found neither in nanoparticles with several nanometer diams. nor in organometallic complexes. Along with the chem. nature of each element, properties of nanoclusters change dramatically with size parameters, making nanoclusters strong potential candidates for future tailor-made materials; these nanoclusters are expected to have attractive properties such as redox activity, catalysis, and magnetism. Alloying of nanoclusters addnl. gives designer functionality by fine control of their electronic structures in addn. to size parameters. Among binary nanoclusters, binary cage superatoms (BCSs) composed of transition metal (M) encapsulating silicon cages, M@Si16, have unique cage structures of 16 silicon atoms, which have not been found in elemental silicon nanoclusters, organosilicon compds., and silicon based clathrates. The unique compn. of these BCSs originates from the simultaneous satisfaction of geometric and electronic shell-closings in terms of cage geometry and valence electron filling, where a total of 68 valence electrons occupy the superat. orbitals of (1S)2(1P)6(1D)10(1F)14(2S)2(1G)18(2P)6(2D)10 for M = group 4 elements in neutral ground state. The most important issue for M@Si16 BCSs is fine-tuning of their characters by replacement of the central metal atoms, M, based on one-by-one adjustment of valence electron counts in the same structure framework of Si16 cage; the replacement of M yields a series of M@Si16 BCSs, based on their superat. characteristics. So far, despite these unique features probed in the gas-phase mol. beam and predicted by quantum chem. calcns., M@Si16 have not yet been isolated.In this Account, we have focused on recent advances in synthesis and characterizations of M@Si16 BCSs (M = Ti and Ta). A series of M@Si16 BCSs (M = groups 3 to 5) was found in gas-phase mol. beam expts. by photoelectron spectroscopy and mass spectrometry: formation of halogen-, rare-gas-, and alkali-like superatoms was identified through one-by-one tuning of no. of total valence electrons. Toward future functional materials in the solid state, we have developed an intensive, size-selected nanocluster source based on high-power impulse magnetron sputtering coupled with a mass spectrometer and a soft-landing app. With scanning probe microscopy and photoelectron spectroscopy, the structure of surface-immobilized BCSs has been elucidated; BCSs can be dispersed in an isolated form using C60 fullerene decoration of the substrate. The intensive nanocluster source also enables the synthesis of BCSs in the 100-mg scale by coupling with a direct liq.-embedded trapping method into org. dispersants, enabling their structure characterization as a highly sym. "metal-encapsulating tetrahedral silicon-cage" (METS) structure with Frank-Kasper geometry.
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490Zheng, W.; Nilles, J. M.; Radisic, D.; Bowen, K. H., Jr Photoelectron spectroscopy of chromium-doped silicon cluster anions. J. Chem. Phys. 2005, 122, 071101, DOI: 10.1063/1.1851984490https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhsFWgtbs%253D&md5=b8d8ba782eca04ab4aa852117719ee60Photoelectron spectroscopy of chromium-doped silicon cluster anionsZheng, Weijun; Nilles, J. Michael; Radisic, Dunja; Bowen, Kit H., Jr.Journal of Chemical Physics (2005), 122 (7), 071101/1-071101/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The photoelectron spectra of Cr-doped Si cluster anions, CrSin-, were measured over the size range, n = 8-12. Their vertical detachment energies are 2.71, 2.88, 2.87, 2.95, and 3.18 eV, resp. The results support theor. calcns. by S.N. Khanna et al. (2002) which found CrSi12 to be an enhanced stability (magic) cluster with its Cr atom encapsulated inside a Si cage and with its magnetic moment completely quenched by the effects of the surrounding cage.
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491Grubisic, A.; Wang, H.; Ko, Y. J.; Bowen, K. H. Photoelectron spectroscopy of europium-silicon cluster anions, EuSin– (3 ⩽ n ⩽ 17). J. Chem. Phys. 2008, 129, 054302, DOI: 10.1063/1.2963500491https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXpslSrsrk%253D&md5=cfa4c29190eac71b7897b99d85b151ddPhotoelectron spectroscopy of europium-silicon cluster anions, EuSin- (3≤n≤17)Grubisic, Andrej; Wang, Haopeng; Ko, Yeon Jae; Bowen, Kit H.Journal of Chemical Physics (2008), 129 (5), 054302/1-054302/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The photoelectron spectra are reported of EuSin- cluster anions (3≤n≤17). They reveal dramatic electronic rearrangements over the size range n = 10-12. In particular, a marked increase in the adiabatic electron affinity of EuSi12 (2.8 eV) compared to its stoichiometric neighbor, EuSi11 (1.9 eV), is obsd. Probably a significant geometric reorganization due to the encapsulation of a Eu atom occurs in this size range and is responsible for the detected changes in the electronic structure. In light of this interpretation, EuSi12 is the smallest fully endohedral Eu-Si cluster. (c) 2008 American Institute of Physics.
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492Grubisic, A.; Ko, Y. J.; Wang, H.; Bowen, K. H. Photoelectron spectroscopy of lanthanide–silicon cluster anions LnSin– (3 ≤ n ≤ 13; Ln = Ho, Gd, Pr, Sm, Eu, Yb): Prospect for magnetic silicon-based clusters. J. Am. Chem. Soc. 2009, 131, 10783– 10790, DOI: 10.1021/ja805205r492https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXotFKnsbg%253D&md5=ef63566d6275627065e204b3a2fdb45aPhotoelectron Spectroscopy of Lanthanide-Silicon Cluster Anions LnSin- (3 ≤ n ≤ 13; Ln = Ho, Gd, Pr, Sm, Eu, Yb): Prospect for Magnetic Silicon-Based ClustersGrubisic, Andrej; Ko, Yeon Jae; Wang, Haopeng; Bowen, Kit H.Journal of the American Chemical Society (2009), 131 (30), 10783-10790CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Photoelectron spectroscopy was used to study a variety of LnSin- cluster anions (Ln = Yb, Eu, Sm, Gd, Ho, Pr; 3 ≤ n ≤ 13). For a particular size n, the measured valence electronic transitions of all these systems fall into either one of two categories, reflecting the influence of the different oxidn. states of the lanthanide atoms involved. In one, the spectra of YbSin- and EuSin- are nearly identical to each other, while in the other the spectra of GdSin-, HoSin-, and PrSin- are essentially identical. SmSin- clusters exhibit an intermediate behavior with smaller clusters resembling the former category and larger clusters resembling the latter category. In the intermediate size range, 7 ≤ n ≤ 10, for SmSin- both categories appear to be present, with one matching the EuSin--like systems and the other HoSin--like clusters. The distinction between LnSin- categories strongly correlates with the oxidn. state of the particular lanthanide as usually found in its compds. Among the Ln-Si clusters studied herein, Yb, Eu, and in case of Sm, sizes n ≥ 10, adopt a nominal +2 oxidn. state while Ho, Pr, Gd, and in case of Sm, sizes n ≤ 7, exhibit a nominal +3 oxidn. state. Also, dramatic increases in adiabatic electron affinity values obsd. at n = 10 for the LnIIISin series and at n = 12 for the LnIISin series were attributed to an inherent electronic stabilization of those particular clusters, rather than to the lanthanides' encapsulation. The obsd. limited effect of f-electrons on the valence electronic structure and thus on bonding in LnSin- clusters may leave these electrons available for inducing magnetism. Consequently, Ln@Sin clusters may hold promise as building blocks of Si-based cluster materials with magnetic properties.
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493Zamudio-Bayer, V.; Leppert, L.; Hirsch, K.; Langenberg, A.; Rittmann, J.; Kossick, M.; Vogel, M.; Richter, R.; Terasaki, A.; Möller, T. Coordination-driven magnetic-to-nonmagnetic transition in manganese-doped silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2013, 88, 115425, DOI: 10.1103/PhysRevB.88.115425493https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslCjtb7I&md5=04da0052e860fb119c3c38a2197092cbCoordination-driven magnetic-to-nonmagnetic transition in manganese-doped silicon clustersZamudio-Bayer, V.; Leppert, L.; Hirsch, K.; Langenberg, A.; Rittmann, J.; Kossick, M.; Vogel, M.; Richter, R.; Terasaki, A.; Moeller, T.; Issendorff, B. V.; Kuemmel, S.; Lau, T.Physical Review B: Condensed Matter and Materials Physics (2013), 88 (11), 115425/1-115425/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The interaction of a single manganese impurity with silicon is analyzed in a combined exptl. and theor. study of the electronic, magnetic, and structural properties of manganese-doped silicon clusters. The structural transition from exohedral to endohedral doping coincides with 3d electron delocalization and a quenching of high-spin states. For all geometric structures investigated, we find a correlation of the magnetic moment with the manganese coordination no. and nearest-neighbor distance. This observation can be generalized to manganese point defects in bulk silicon, whose magnetic moments fall within the obsd. magnetic-to-nonmagnetic transition, and therefore react very sensitively to changes in the local geometry. The results indicate that high-spin states in manganese-doped silicon could be stabilized by an appropriate lattice expansion.
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494Lau, J.; Vogel, M.; Langenberg, A.; Hirsch, K.; Rittmann, J.; Zamudio-Bayer, V.; Möller, T.; Issendorff, B. v. Communication: Highest occupied molecular orbital–lowest unoccupied molecular orbital gaps of doped silicon clusters from core level spectroscopy. J. Chem. Phys. 2011, 134, 041102, DOI: 10.1063/1.3547699494https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVOhu7o%253D&md5=cd30c4b54a8ba0e1e8f9c1f820abe87cHighest occupied molecular orbital-lowest unoccupied molecular orbital gaps of doped silicon clusters from core level spectroscopyLau, J. T.; Vogel, M.; Langenberg, A.; Hirsch, K.; Rittmann, J.; Zamudio-Bayer, V.; Moeller, T.; von Issendorff, B.Journal of Chemical Physics (2011), 134 (4), 041102/1-041102/3CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A method to det. band gaps of size-selected and isolated nanoparticles by combination of valence band and core-level photoionization spectroscopy is presented. This approach is widely applicable and provides a convenient alternative to current std. techniques for the detn. of band gaps by optical or photoelectron spectroscopy. A 1st application to V doped Si clusters confirms a striking size-dependence of their HOMO-LUMO gaps. (c) 2011 American Institute of Physics.
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495Ngan, V. T.; Gruene, P.; Claes, P.; Janssens, E.; Fielicke, A.; Nguyen, M. T.; Lievens, P. Disparate effects of Cu and V on structures of exohedral transition metal-doped silicon clusters: A combined far-infrared spectroscopic and computational study. J. Am. Chem. Soc. 2010, 132, 15589– 15602, DOI: 10.1021/ja105099u495https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlWmtLnI&md5=f87ef1c6f559f14b034fcb85418bd2ffDisparate Effects of Cu and V on Structures of Exohedral Transition Metal-Doped Silicon Clusters: A Combined Far-Infrared Spectroscopic and Computational StudyNgan, Vu Thi; Gruene, Philipp; Claes, Pieterjan; Janssens, Ewald; Fielicke, Andre; Nguyen, Minh Tho; Lievens, PeterJournal of the American Chemical Society (2010), 132 (44), 15589-15602CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The growth mechanisms of small cationic silicon clusters contg. up to 11 Si atoms, exohedrally doped by V and Cu atoms, are described. We find that as dopants, V and Cu follow two different paths: while V prefers substitution of a silicon atom in a highly coordinated position of the cationic bare silicon clusters, Cu favors adsorption to the neutral or cationic bare clusters in a lower coordination site. The different behavior of the two transition metals becomes evident in the structures of SinM+ (n = 4-11 for M = V, and n = 6-11 for M = Cu), which are investigated by d. functional theory and, for several sizes, confirmed by comparison with their exptl. vibrational spectra. The spectra are measured on the corresponding SinM+·Ar complexes, which can be formed for the exohedrally doped silicon clusters. The comparison between exptl. and calcd. spectra indicates that the BP86 functional is suitable to predict far-IR spectra of these clusters. In most cases, the calcd. IR spectrum of the lowest-lying isomer fits well with the expt., even when various isomers and different electronic states are close in energy. However, in a few cases, namely Si9Cu+, Si11Cu+, and Si10V+, the exptl. verified isomers are not the lowest in energy according to the d. functional theory calcns., but their structures still follow the described growth mechanism. The different growth patterns of the two series of doped Si clusters reflect the role of the transition metal's 3d orbitals in the binding of the dopant atoms.
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496Claes, P.; Janssens, E.; Ngan, V.; Gruene, P.; Lyon, J. T.; Harding, D. J.; Fielicke, A.; Nguyen, M.; Lievens, P. Structural identification of caged vanadium doped silicon clusters. Phys. Rev. Lett. 2011, 107, 173401, DOI: 10.1103/PhysRevLett.107.173401496https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVWks77O&md5=d8499d24e44c5f191810042b974e852eStructural Identification of Caged Vanadium Doped Silicon ClustersClaes, P.; Janssens, E.; Ngan, V. T.; Gruene, P.; Lyon, J. T.; Harding, D. J.; Fielicke, A.; Nguyen, M. T.; Lievens, P.Physical Review Letters (2011), 107 (17), 173401/1-173401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)The geometry of cationic silicon clusters doped with vanadium, SinV+ (n=12-16), is investigated by using IR multiple photon dissocn. of the corresponding rare gas complexes in combination with ab initio calcns. It is shown that the clusters are endohedral cages, and evidence is provided that Si16V+ is a fluxional system with a sym. Frank-Kasper geometry.
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497Ngan, V. T.; Janssens, E.; Claes, P.; Lyon, J. T.; Fielicke, A.; Nguyen, M. T.; Lievens, P. High magnetic moments in manganese-doped silicon clusters. Chem. - Eur. J. 2012, 18, 15788– 15793, DOI: 10.1002/chem.201201839497https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFGktrvO&md5=bfea1498f58aaf3b222e7652b4f9a05bHigh Magnetic Moments in Manganese-Doped Silicon ClustersNgan, Vu Thi; Janssens, Ewald; Claes, Pieterjan; Lyon, Jonathan T.; Fielicke, Andre; Nguyen, Minh Tho; Lievens, PeterChemistry - A European Journal (2012), 18 (49), 15788-15793, S15788/1-S15788/27CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors report on the structural, electronic, and magnetic properties of manganese-doped silicon clusters cations, SinMn+ with n = 6-10, 12-14, and 16, using mass spectrometry and IR spectroscopy in combination with d. functional theory computations. This combined exptl. and theor. study allows several structures to be identified. All the exohedral SinMn+ (n = 6-10) clusters are substitutive derivs. of the bare Sin+1+ cations, while the endohedral SinMn+ (n = 12-14 and 16) clusters adopt fullerene-like structures. The hybrid B3P86 functional is appropriate in predicting the ground electronic states of the clusters and in reproducing their IR spectra. The clusters turn out to have high magnetic moments localized on Mn. In particular the Mn atoms in the exohedral SinMn+ (n = 6-10) clusters have local magnetic moments of 4 μB or 6 μB and can be considered as magnetic copies of the silicon atoms. Opposed to other 3d transition-metal dopants, the local magnetic moment of the Mn atom is not completely quenched when encapsulated in a silicon cage.
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498Li, X.; Claes, P.; Haertelt, M.; Lievens, P.; Janssens, E.; Fielicke, A. Structural determination of niobium-doped silicon clusters by far-infrared spectroscopy and theory. Phys. Chem. Chem. Phys. 2016, 18, 6291– 6300, DOI: 10.1039/C5CP07298K498https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2gt7o%253D&md5=81196e72d0614b441554e50fc79c77f0Structural determination of niobium-doped silicon clusters by far-infrared spectroscopy and theoryLi, Xiaojun; Claes, Pieterjan; Haertelt, Marko; Lievens, Peter; Janssens, Ewald; Fielicke, AndrePhysical Chemistry Chemical Physics (2016), 18 (8), 6291-6300CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures of cationic clusters SinNb+ n = 4-12 are detd. using the combination of IR multiple photon dissocn., IR-MPD, and d. functional theory DFT calcns. The exptl. IR-MPD spectra of the argon complexes of SinNb+ are assigned by comparison to the calcd. IR spectra of low-energy structures of SinNb+ that are identified using the stochastic 'random kick' algorithm in conjunction with the BP86 GGA functional. It is found that the Nb dopant tends to bind in an apex position of the Sin framework for n = 4-9 and in surface positions with high coordination nos. for n = 10-12. For the larger doped clusters, it is suggested that multiple isomers coexist and contribute to the exptl. spectra. The structural evolution of SinNb+ clusters is similar to V-doped silicon clusters J. Am. Chem. Soc., 2010, 132, 15589-15602, except for the largest size investigated n = 12, since V takes an endohedral position in Si12V+. The interaction with a Nb atom, with its partially unfilled 4d orbitals leads to a significant stability enhancement of the Sin framework as reflected, e.g. by high binding energies and large HOMO-LUMO gaps.
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499Li, Y.; Tam, N. M.; Claes, P.; Woodham, A. P.; Lyon, J. T.; Ngan, V. T.; Nguyen, M. T.; Lievens, P.; Fielicke, A.; Janssens, E. Structure assignment, electronic properties, and magnetism quenching of endohedrally doped neutral silicon clusters, SinCo (n = 10–12). J. Phys. Chem. A 2014, 118, 8198– 8203, DOI: 10.1021/jp500928t499https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXms1Wgtbs%253D&md5=db4c69f5ca8ceff99f529da91c96870aStructure Assignment, Electronic Properties, and Magnetism Quenching of Endohedrally Doped Neutral Silicon Clusters, SinCo (n = 10-12)Li, Yejun; Tam, Nguyen Minh; Claes, Pieterjan; Woodham, Alex P.; Lyon, Jonathan T.; Ngan, Vu Thi; Nguyen, Minh Tho; Lievens, Peter; Fielicke, Andre; Janssens, EwaldJournal of Physical Chemistry A (2014), 118 (37), 8198-8203CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The structures of neutral cobalt-doped silicon clusters have been assigned by a combined exptl. and theor. study. Size-selective IR spectra of neutral SinCo (n = 10-12) clusters are measured using a tunable IR-UV two-color ionization scheme. The exptl. IR spectra are compared with calcd. spectra of low-energy structures predicted at the B3P86 level of theory. It is shown that the SinCo (n = 10-12) clusters have endohedral caged structures, where the silicon frameworks prefer double-layered structures encapsulating the Co atom. Electronic structure anal. indicates that the clusters are stabilized by an ionic interaction between the Co dopant atom and the silicon cage due to the charge transfer from the silicon valence sp orbitals to the cobalt 3d orbitals. Strong hybridization between the Co dopant atom and the silicon host quenches the local magnetic moment on the encapsulated Co atom.
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500Cheshnovsky, O.; Yang, S.; Pettiette, C.; Craycraft, M.; Liu, Y.; Smalley, R. Ultraviolet photoelectron spectroscopy of semiconductor clusters: Silicon and germanium. Chem. Phys. Lett. 1987, 138, 119– 124, DOI: 10.1016/0009-2614(87)80353-6There is no corresponding record for this reference.
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501Hoffmann, M. A.; Wrigge, G.; Issendorff, B. v.; Müller, J.; Ganteför, G.; Haberland, H. Ultraviolet photoelectron spectroscopy of Si4 to Si1000. Eur. Phys. J. D 2001, 16, 9– 11, DOI: 10.1007/s100530170048501https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXosV2gurk%253D&md5=0a8e383e449d3fc99936af63b003885fUltraviolet photoelectron spectroscopy of Si4- to Si1000-Hoffmann, M. Astruc; Wrigge, G.; von Issendorff, B.; Muller, J.; Gantefor, G.; Haberland, H.European Physical Journal D: Atomic, Molecular and Optical Physics (2001), 16 (1-3), 9-11CODEN: EPJDF6; ISSN:1434-6060. (Springer-Verlag)Using a new exptl. setup the authors have measured UV (hv = 6.4 eV) photoelectron spectra of cold Si cluster anions Sin- in a very broad size range. For sizes up to n = 46 the spectra exhibit rich structures. For larger sizes only smooth spectra were obtained. No trace of a bandgap was found even for clusters with >1000 atoms.
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502Meloni, G.; Ferguson, M. J.; Sheehan, S. M.; Neumark, D. M. Probing structural transitions of nanosize silicon clusters via anion photoelectron spectroscopy at 7.9 eV. Chem. Phys. Lett. 2004, 399, 389– 391, DOI: 10.1016/j.cplett.2004.10.030502https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVShsr3P&md5=d276e3824c872d1730b3981df152a6d1Probing structural transitions of nanosize silicon clusters via anion photoelectron spectroscopy at 7.9 eVMeloni, Giovanni; Ferguson, Michael J.; Sheehan, Sean M.; Neumark, Daniel M.Chemical Physics Letters (2004), 399 (4-6), 389-391CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Photoelectron spectra of silicon cluster anions as large as Si35- have been obtained with vacuum UV radiation at 157 nm (7.9 eV). The data show spectroscopic trends consistent with the structural transformation from prolate to more spherical clusters previously obsd. in ion mobility expts. In addn., we observe signal at high electron binding energy that may be analogous to the second band seen in the photoemission spectrum of bulk silicon.
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503Akola, J.; Manninen, M.; Häkkinen, H.; Landman, U.; Li, X.; Wang, L.-S. Photoelectron spectra of aluminum cluster anions: Temperature effects and ab initio simulations. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 60, R11297– R11300, DOI: 10.1103/PhysRevB.60.R11297503https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmvFOhu7g%253D&md5=3f597dd6157f3604bc0c37dd9f3a6cdePhotoelectron spectra of aluminum cluster anions: Temperature effects and ab initio simulationsAkola, Jaakko; Manninen, Matti; Hakkinen, Hannu; Landman, Uzi; Li, Xi; Wang, Lai-ShengPhysical Review B: Condensed Matter and Materials Physics (1999), 60 (16), R11297-R11300CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Photoelectron (PES) spectra from Al cluster anions, Aln- (12 ≤ n ≤ 15), at various temp. regimes, were studied using ab initio mol. dynamics simulations and exptl. The calcd. PES spectra, obtained via shifting of the simulated electronic densities of states by the self-consistently detd. values of the asymptotic exchange-correlation potential, agree well with the measured ones, allowing reliable structural assignments and theor. estn. of the clusters' temps.
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504Honea, E.; Ogura, A.; Peale, D.; Felix, C.; Murray, C.; Raghavachari, K.; Sprenger, W.; Jarrold, M.; Brown, W. Structures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopy. J. Chem. Phys. 1999, 110, 12161– 12172, DOI: 10.1063/1.479153504https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXjsFWjt78%253D&md5=d326e8fdd1574b7e2726c25dd053080bStructures and coalescence behavior of size-selected silicon nanoclusters studied by surface-plasmon-polariton enhanced Raman spectroscopyHonea, E. C.; Ogura, A.; Peale, D. R.; Felix, C.; Murray, C. A.; Raghavachari, K.; Sprenger, W. O.; Jarrold, M. F.; Brown, W. L.Journal of Chemical Physics (1999), 110 (24), 12161-12172CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures and coalescence behavior of size-selected, matrix-isolated silicon clusters have been studied using surface-plasmon-polariton (SPP) enhanced Raman spectroscopy. The cluster ions were produced in a laser vaporization source, mass selected then deposited into a co-condensed matrix of Ar, Kr or N2 on a liq. He cooled substrate. Raman spectra from monodisperse samples of the smaller clusters studied, Si4, Si6 and Si7, show sharp, well-resolved, vibrations which are in good agreement with predictions based on ab initio calcns. From these comparisons it was confirmed that Si4 is a planar rhombus, and assign Si6 as a distorted octahedron and Si7 as a pentagonal bipyramid. Si5 depositions down to 5 eV did not reveal a measurable Raman spectrum under our exptl. conditions. Evidence for cluster-cluster aggregation (or fragmentation) was obsd. under some conditions, even for a "magic no." cluster such as Si6. The spectra of the aggregated small clusters were identical to those obsd. for directly deposited larger cluster "bands," such as Si25-35. The Raman spectra of the aggregated clusters bear some similarity to those of bulk amorphous silicon. Cluster-deposited thin films were prepd. by sublimating the matrix material. Even under these "soft landing" conditions, changes in the Raman spectrum are obsd. with the thin films showing even greater similarity to amorphous silicon.
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505Pichierri, F.; Kumar, V.; Kawazoe, Y. Exohedral functionalization of the icosahedral cluster Si20H20: A density functional theory study. Chem. Phys. Lett. 2004, 383, 544– 548, DOI: 10.1016/j.cplett.2003.11.087505https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXpvF2ns78%253D&md5=1767bed9d7d2650e1e11e8925c45f457Exohedral functionalization of the icosahedral cluster Si20H20: a density functional theory studyPichierri, Fabio; Kumar, Vijay; Kawazoe, YoshiyukiChemical Physics Letters (2004), 383 (5,6), 544-548CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)D. functional theory calcns. on three derivs. of the recently predicted hydrogenated Si fullerene cluster Si20H20 using the B3PW91 hybrid exchange-correlation functional with the 6-311 + G(d) basis set is reported. The cluster was exohedrally functionalized by replacing one of its H atoms with -CH2OH, -COOH, and -CONH2. The resulting functionalized clusters have nearly the same HOMO-LUMO gaps as that of the perhydrogenated Si fullerene leading to the possibility of developing new Si fullerene-based mols. for medico-biol. applications. The deprotonated Si20H19(COO-) cluster displays a very large permanent dipole moment along with a strongly localized HOMO on its carboxyl group.
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506Pichierri, F.; Kumar, V.; Kawazoe, Y. Encapsulation of halide anions in perhydrogenated silicon fullerene: X–@Si20H20 (X= F, Cl, Br, I). Chem. Phys. Lett. 2005, 406, 341– 344, DOI: 10.1016/j.cplett.2005.02.121506https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjtF2gsbg%253D&md5=d48aa75c1c7c435252a9a8b900264364Encapsulation of halide anions in perhydrogenated silicon fullerene: X-@Si20H20 (X=F, Cl, Br, I)Pichierri, Fabio; Kumar, Vijay; Kawazoe, YoshiyukiChemical Physics Letters (2005), 406 (4-6), 341-344CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We report the results of a d. functional study of the encapsulation of halide anions into the dodecahedral cage of the perhydrogenated silicon fullerene Si20H20. The HOMO-LUMO energy gap of the endohedral complexes X-@Si20H20 (X = F, Cl, Br, I) is only ∼0.5 eV larger than that computed for the empty fullerene. The amt. of charge that is being transferred from the encapsulated anion to the fullerene increases from F- (∼10%) to I- ( > 70%). Only the encapsulation of Br- does not alter the cage thus indicating that this spherical anion might be employed in the anion-templated synthesis of the elusive Si20H20 cluster.
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507Tillmann, J.; Wender, J. H.; Bahr, U.; Bolte, M.; Lerner, H. W.; Holthausen, M. C.; Wagner, M. One-Step synthesis of a [20] silafullerane with an endohedral chloride ion. Angew. Chem., Int. Ed. 2015, 54, 5429– 5433, DOI: 10.1002/anie.201412050507https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkvF2ms7c%253D&md5=644a3970c6a0c5152dc3e18bb98dd94bOne-Step Synthesis of a [20]Silafullerane with an Endohedral Chloride IonTillmann, Jan; Wender, Josef Heinrich; Bahr, Ute; Bolte, Michael; Lerner, Hans-Wolfram; Holthausen, Max C.; Wagner, MatthiasAngewandte Chemie, International Edition (2015), 54 (18), 5429-5433CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Silicon analogs of the most prominent carbon nanostructures, namely, hollow spheroidals such as C60 and the fullerene family, have been unknown to date. Herein authors show that discrete Si20 dodecahedra, stabilized by an endohedral guest and valence satn., are accessible in preparative yields through a chloride-induced disproportionation reaction of hexachlorodisilane in the presence of tri(n-butyl)amine. X-ray crystallog. revealed that each silicon dodecahedron contains an endohedral chloride ion that imparts a net neg. charge. Eight chloro substituents and twelve trichlorosilyl groups are attached to the surface of each cluster in a strictly regioregular arrangement, a thermodynamically preferred substitution pattern according to quantum-chem. assessment. The results demonstrate that the wet-chem. self-assembly of a complex, monodisperse Si nanostructure is possible under mild conditions starting from simple Si2 building blocks.
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508Wigner, E.; Witmer, E. Über die struktur der zweiatomigen molekelspektren nach der quantenmechanik. Eur. Phys. J. A 1928, 51, 859– 886, DOI: 10.1007/BF01400247There is no corresponding record for this reference.
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509Nolas, G. S. The physics and chemistry of inorganic clathrates; Springer: Dordrecht, 2014.There is no corresponding record for this reference.
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510Emsley, J. The elements; Oxford University Press: New York, 1991.There is no corresponding record for this reference.
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511He, J.; Wu, K.; Sa, R.; Li, Q.; Wei, Y. (Hyper) polarizabilities and optical absorption spectra of MSi12 clusters (M = Sc–Zn): A theoretical study. Chem. Phys. Lett. 2010, 490, 132– 137, DOI: 10.1016/j.cplett.2010.03.038511https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkvVertLY%253D&md5=36f9f898236fa03461083e3d321bdf9d(Hyper)polarizabilities and optical absorption spectra of MSi12 clusters (M=Sc-Zn): A theoretical studyHe, Jiangang; Wu, Kechen; Sa, Rongjian; Li, Qiaohong; Wei, YongqinChemical Physics Letters (2010), 490 (4-6), 132-137CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The dipole polarizabilities, 2nd-order hyperpolarizabilities, and optical absorption spectra of MSi12 clusters (M = Sc-Zn) were studied by using the (time-dependent) d. functional theory. The correlation functional exerts more remarkable influence on the dipole polarizability and 2nd-order hyperpolarizability calcns. than the exchange term. Referring to MP2 results, B3LYP provides poorer dipole polarizabilities but more reliable 2nd-order hyperpolarizabilities than B3PW91 and mPW1PW91 functionals. Addnl., the tunable (hyper)polarizabilities and optical absorption spectra were evidently obsd., which are attributed to the strong hybridization between 3d orbitals of M and 3s, 3p states of Si.
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512Kong, L.; Chelikowsky, J. R. Transport properties of transition-metal-encapsulated Si cages. Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 073401, DOI: 10.1103/PhysRevB.77.073401512https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtFaqtrs%253D&md5=cfb9acc96819b25f6a70a67942e10c81Transport properties of transition-metal-encapsulated Si cagesKong, Lingzhu; Chelikowsky, James R.Physical Review B: Condensed Matter and Materials Physics (2008), 77 (7), 073401/1-073401/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We performed d. functional pseudopotential calcns. of the spin-dependent transport through transition-metal-atom-encapsulated Si cages Si12X (X = Mn, Fe, and Co). The effect of the metal atom on conductance is studied. Mn- and Fe-doped systems show highly spin-polarized transmission whereas the magnetization in Co-doped system is quenched. Electrons are transferred from Si atoms into the minority d orbitals of the metal atoms. The conductance decreases as these electrons become localized around the encapsulated atoms.
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513Kawamura, H.; Kumar, V.; Kawazoe, Y. Water adsorption on Ti-doped silicon clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 193402, DOI: 10.1103/PhysRevB.70.193402513https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVGhu77K&md5=05b1a2b0573369f608ca0b3b4c10df99Water adsorption on Ti-doped silicon clustersKawamura, Hiroaki; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 70 (19), 193402/1-193402/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Ab initio calcns. were performed on adsorption of H2O mols. on Ti-doped silicon clusters TiSin using the ultrasoft pseudopotential method within the generalized gradient approxn. For n = 13 and larger clusters adsorption of H2O on TiSin could be difficult due to low binding energies. All these clusters have cage structures with the metal atom surrounded by the silicon atoms. On the other hand, smaller clusters with n <13 have the metal atom partially covered by Si atoms in a basket structure so that it is available for reaction with a water mol. This leads to significantly higher binding energies of a water mol. on such clusters. These results are in excellent agreement with the available exptl. data, which show significant decrease of H2O adsorption on clusters with n >12.
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514Shibuta, M.; Kamoshida, T.; Ohta, T.; Tsunoyama, H.; Nakajima, A. Oxidative reactivity of alkali-like superatoms of group 5 metal-encapsulating Si16 cage nanoclusters. Comm. Chem. 2018, 1, 50, DOI: 10.1038/s42004-018-0052-9There is no corresponding record for this reference.
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515Shibuta, M.; Niikura, T.; Kamoshida, T.; Tsunoyama, H.; Nakajima, A. Nitric oxide oxidation of a Ta encapsulating Si cage nanocluster superatom (Ta@Si16) deposited on an organic substrate; a Si cage collapse indicator. Phys. Chem. Chem. Phys. 2018, 20, 26273– 26279, DOI: 10.1039/C8CP05580G515https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVamt7%252FE&md5=7b972c030f6c09326928f80d3eb38751Nitric oxide oxidation of a Ta encapsulating Si cage nanocluster superatom (Ta@Si16) deposited on an organic substrate; a Si cage collapse indicatorShibuta, Masahiro; Niikura, Toshiki; Kamoshida, Toshiaki; Tsunoyama, Hironori; Nakajima, AtsushiPhysical Chemistry Chemical Physics (2018), 20 (41), 26273-26279CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The chem. reaction kinetics of an alkali-like superatom comprising a tantalum encapsulating Si16 cage nanocluster (Ta@Si16) deposited on an n-type org. substrate composed of overlayered C60 fullerene upon exposure to nitric oxide (NO) as a reactive gas are investigated. Core level XPS reveals that Ta@Si16 oxidn. with NO proceeds stepwise from the outer Si16 cage to the central Ta atom; during the initial stage, NO is dissociatively chemisorbed by the cage surface of Ta@Si16 without penetrating the cage, while under extreme reaction conditions, the collapse of the Si16 cage leads to NO oxidn. of the central Ta atom. In particular, mol. NO adsorption is assocd. with Ta oxidn. only after the collapse of the Si16 cage of Ta@Si16. The reaction kinetics of M@Si16 with NO in the earlier stages of oxidn. are discussed in conjunction with d. functional theory calcns. Due to the superat. nature of the shell closure with valence electrons coupled with metal encapsulation, surface oxidn. of the caged Si in Ta@Si16 takes place gently compared to that of a naked Si surface, with molecularly physisorbed NO functioning as an indicator of Si cage collapse.
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516Belomoin, G.; Therrien, J.; Smith, A.; Rao, S.; Twesten, R.; Chaieb, S.; Nayfeh, M. H.; Wagner, L.; Mitas, L. Observation of a magic discrete family of ultrabright Si nanoparticles. Appl. Phys. Lett. 2002, 80, 841– 843, DOI: 10.1063/1.1435802516https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xpt1emsw%253D%253D&md5=6b6373a0bfd5687b50e7fe4648674fceObservation of a magic discrete family of ultrabright Si nanoparticlesBelomoin, G.; Therrien, J.; Smith, A.; Rao, S.; Twesten, R.; Chaieb, S.; Nayfeh, M. H.; Wagner, L.; Mitas, L.Applied Physics Letters (2002), 80 (5), 841-843CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Electrochem. etched, H capped SinHx clusters with n > 20 are obtained within a family of discrete sizes. These sizes are 1.0 (Si29), 1.67 (Si123), 2.15, 2.9, and 3.7 nm in diam. The particles were characterize via direct electron imaging, excitation and emission optical spectroscopy, and colloidal crystn. The band gaps and emission bands are measured. The smallest 4 are ultrabright blue, green, yellow and red luminescent particles. The availability of discrete sizes and distinct emission in the red, green and blue (RGB) range is useful for biomedical tagging, RGB displays, and flash memories.
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517Li, S.; Xue, X.; Zhai, H.; Nie, X.; Wang, F.; Sun, Q.; Jia, Y.; Guo, Z.; Shevlin, S. High inertness of W@Si12 cluster toward O2 molecule. Phys. Lett. A 2012, 376, 1454– 1459, DOI: 10.1016/j.physleta.2012.03.005517https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjvVajsr0%253D&md5=a338ff01fe2818456058f94cb7116cb8High inertness of W@Si12 cluster toward O2 moleculeLi, S. F.; Xue, Xinlian; Zhai, Hao; Nie, Xinchuang; Wang, Fei; Sun, Q.; Jia, Yu; Guo, Z. X.; Shevlin, S. A.Physics Letters A (2012), 376 (17), 1454-1459CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The geometry, electronic structure, and reactivity with O2 mols. of an isolated W@Si12 cluster have been investigated by first principles simulations. The results confirm that O2 can weakly adsorb on the HP-W@Si12 cage with a binding energy of 0.004 to 0.027 eV. O2 may dissoc. on the cluster by overcoming energy barrier of at least 0.593 eV. However, this is a spin-forbidden reaction, rendering the high inertness of the HP-W@Si12 cluster toward O2. These results confirm the high inertness of the W@Si12 cluster toward O2 mols. in ambient conditions, in close agreement with exptl. observations of magic cluster of W@Si12.
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518Yong, Y.; Lv, S.; Li, X.; Li, T.; Cui, H. W@Si12 cluster as a potential sensor for CO and NO detection. EPL 2015, 111, 10006, DOI: 10.1209/0295-5075/111/10006There is no corresponding record for this reference.
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519Zhou, S.; Yang, X.; Pei, W.; Zhao, J.; Du, A. Silicon nanocages for selective carbon dioxide conversion under visible light. J. Phys. Chem. C 2019, 123, 9973– 9980, DOI: 10.1021/acs.jpcc.9b01784519https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXmtlKntro%253D&md5=d90e926f8fab6b423d9d51ec665d7a37Silicon Nanocages for Selective Carbon Dioxide Conversion under Visible LightZhou, Si; Yang, Xiaowei; Pei, Wei; Zhao, Jijun; Du, AijunJournal of Physical Chemistry C (2019), 123 (15), 9973-9980CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Artificial photosynthesis for CO2 conversion to fuels and value-added chems. is a tactic to close the anthropogenic carbon cycle. To this end, developing efficient catalysts composed of earth-abundant, economic, and eco-friendly elements is desirable but challenging. By comprehensive ab initio calcns., wit is shown for the first time that caged silicon clusters doped by vanadium atom (VSin, n = 12-15) can catalyze CO2 hydrogenation to various C1 products (i.e., carbon monoxide, formic acid, formaldehyde, methanol, and methane) with kinetic barriers down to 0.67-1.53 eV and selectivity uniquely detd. by cluster size and geometry. These clusters, which can be produced in lab. with good stability, have suitable energy gap and can absorb sunlight from the visible to UV regime for driving the catalysis. Hence, these metal-doped Si clusters form a potential family of photocatalysts for selective CO2 hydrogenation. Their superior catalytic activity stems from the unsatd. states of the Si cage, which are mediated by sp-d hybridization and V-Si charge transfer. The CO2 adsorption strength is correlated with the coordination no. and p orbital center of Si atoms. Such geometry-electronic structure-activity correlation should be applicable to the atomically precise design of novel silicon-based nanocatalysts for various renewable energy applications.
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520Zhou, S.; Yang, X.; Pei, W.; Liu, N.; Zhao, J. Heterostructures of MXenes and N-doped graphene as highly active bifunctional electrocatalysts. Nanoscale 2018, 10, 10876– 10883, DOI: 10.1039/C8NR01090K520https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXksVelur0%253D&md5=2e7596e6f26ada6a3901ca94da0a755dHeterostructures of MXenes and N-doped graphene as highly active bifunctional electrocatalystsZhou, Si; Yang, Xiaowei; Pei, Wei; Liu, Nanshu; Zhao, JijunNanoscale (2018), 10 (23), 10876-10883CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)MXenes with versatile chem. and superior elec. cond. are prevalent candidate materials for energy storage and catalysts. Inspired by recent expts. of hybridizing MXenes with carbon materials, here we theor. design a series of heterostructures of N-doped graphene supported by MXene monolayers as bifunctional electrocatalysts for the oxygen redn. reaction (ORR) and hydrogen evolution reaction (HER). Our first-principles calcns. show that the graphitic sheet on V2C and Mo2C MXenes are highly active with an ORR overpotential down to 0.36 V and reaction free energies for the HER approaching zero, both with low kinetic barriers. Such outstanding catalytic activities originate from the electronic coupling between the graphitic sheet and the MXene, and can be correlated with the pz band center of surface carbon atoms and the work function of the heterostructures. Our findings screen a novel form of highly active electrocatalysts by taking advantage of the fast charge transfer kinetics and strong interfacial coupling of MXenes, and illuminate a universal mechanism for modulating the catalytic properties of two-dimensional hybrid materials.
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521Pei, W.; Zhou, S.; Bai, Y.; Zhao, J. N-doped graphitic carbon materials hybridized with transition metals (compounds) for hydrogen evolution reaction: Understanding the synergistic effect from atomistic level. Carbon 2018, 133, 260– 266, DOI: 10.1016/j.carbon.2018.03.043521https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXltlSnsbc%253D&md5=a6336494c5b80b1a300506ba7b0b0838N-doped graphitic carbon materials hybridized with transition metals (compounds) for hydrogen evolution reaction: Understanding the synergistic effect from atomistic levelPei, Wei; Zhou, Si; Bai, Yizhen; Zhao, JijunCarbon (2018), 133 (), 260-266CODEN: CRBNAH; ISSN:0008-6223. (Elsevier Ltd.)The hybrid nanostructures of nitrogen doped carbon materials and nonprecious transition metals are among the most promising electrocatalysts to replace noble metal catalysts for renewable energy applications. However, the fundamental principles governing the catalytic activity of such hybrid materials remain elusive. Herein, we systematically explore the electrocatalytic properties of transition metals, transition metal oxides and carbides substrates covered by nitrogen-doped graphitic sheets for hydrogen evolution reaction (HER). Our first-principles calcns. show that the graphitic sheet is prominently activated by the nitrogen doping and the coordinate bond with metal (compd.) substrate through intralayer and interlayer charge transfer. Such hybrid materials can provide optimal binding capability for HER catalysis with Tafel barrier down to 1.0 eV. The HER activity can be correlated to the C pz band center, which is in turn governed by the electronic coupling strength between the graphitic sheet and metal substrate, thus paving a way to rational design of graphitic carbon/transition metal hybrid electrocatalysts of high performance.
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522Hunter, J.; Fye, J.; Jarrold, M.; Bower, J. Structural transitions in size-selected germanium cluster ions. Phys. Rev. Lett. 1994, 73, 2063– 2066, DOI: 10.1103/PhysRevLett.73.2063522https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXmvFWiu7g%253D&md5=e91a3e242152c8fa7995d501cf0c3df2Structural transitions in size-selected germanium cluster ionsHunter, J. M.; Fye, J. L.; Jarrold, M. F.Physical Review Letters (1994), 73 (15), 2063-6CODEN: PRLTAO; ISSN:0031-9007.Injected ion drift tube techniques were used to probe the geometries of germanium cluster ions. Clusters with ∼(10-40) atoms appear to follow a 1-dimensional growth sequence to give prolate geometries. At ∼40 atoms the clusters stop following this growth sequence, and clusters with ∼(40-70) atoms appear to retain roughly the same aspect ratio. At ∼70 atoms the clusters abruptly reconstruct to a more spherical geometry. Dissocn. energies, measured for the germanium clusters, suggest that clusters with n < 70 can be thought of as loosely bound assemblies of small strongly bound fragments (such as Ge7 and Ge10). Apparently the structural transition at ∼70 atoms may reflect a change to a more bulklike bonding arrangement.
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523Burton, G. R.; Xu, C.; Arnold, C. C.; Neumark, D. M. Photoelectron spectroscopy and zero electron kinetic energy spectroscopy of germanium cluster anions. J. Chem. Phys. 1996, 104, 2757– 2764, DOI: 10.1063/1.471098523https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xht1Kru7g%253D&md5=50cc3a390d235a1f51588f5160c8ee1cPhotoelectron spectroscopy and zero electron kinetic energy spectroscopy of germanium cluster anionsBurton, Gordon R.; Xu, Cangshan; Arnold, Caroline C.; Neumark, Daniel M.Journal of Chemical Physics (1996), 104 (8), 2757-64CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Anion photoelectron spectra of Gen-, n = 2-15, have been measured using an incident photon energy of 4.66 eV. In addn., the spectra of Ge2-, Ge3-, and Ge4- have been measured at photon energies of 3.49 and 2.98 eV. From these spectra the electron affinity of the corresponding neutral cluster has been detd. Vibrational frequencies and term values for several electronic states of Ge2- and Ge3- have been detd. Vibrational structure in the 3B3u excited state of Ge4 has been resolved using zero electron kinetic energy (ZEKE) photoelectron spectroscopy. The assignment of the spectra of Ge3- and Ge4- is facilitated by a comparison to the similar spectra of Si3- and Si4-, resp. The spectra of the larger clusters, Gen-, n = 5-15, are characterized by many broad structureless features which indicate the presence of multiple electronic transitions. Several of these were assigned based on comparison with previous ab initio calcns. on germanium and silicon clusters.
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524Gingerich, K. A.; Schmude, R., Jr; Sai Baba, M.; Meloni, G. Atomization enthalpies and enthalpies of formation of the germanium clusters, Ge5, Ge6, Ge7, and Ge8 by Knudsen effusion mass spectrometry. J. Chem. Phys. 2000, 112, 7443– 7448, DOI: 10.1063/1.481343524https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXis1ans7Y%253D&md5=8f63475962c2ed46008e7677ce6a6f8cAtomization enthalpies and enthalpies of formation of the germanium clusters, Ge5, Ge6, Ge7, and Ge8 by Knudsen effusion mass spectrometryGingerich, K. A.; Schmude, R. W., Jr.; Sai Baba, M.; Meloni, G.Journal of Chemical Physics (2000), 112 (17), 7443-7448CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The high-temp. mass spectrometric method was employed to measure the equil. partial pressures of small germanium clusters above liq. germanium contained in a graphite Knudsen cell. These data were combined with new thermal functions, calcd. from recent theor. and spectroscopic mol. parameters, to evaluate the atomization enthalpies and enthalpies of formation of Ge5-Ge8. Mass spectrometric equil. data available in literature were also reevaluated. The following atomization enthalpies, ΔaH0o(Gen,g) and enthalpies of formation ΔfH298.15o(Gen,g), in kJ mol-1, have been obtained: Ge5, 1313±27 and 548±27, Ge6, 1649±33 and 583±33, Ge7, 2008±42 and 598±42, Ge8, 2359±60 and 618±60. The atomization energies are compared with available theor. values.
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525Schäfer, S.; Schäfer, R. Dielectric response of germanium clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 205211, DOI: 10.1103/PhysRevB.77.205211There is no corresponding record for this reference.
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526Wang, J.; Wang, G.; Zhao, J. Structure and electronic properties of Gen (n = 2–25) clusters from density-functional theory. Phys. Rev. B: Condens. Matter Mater. Phys. 2001, 64, 205411, DOI: 10.1103/PhysRevB.64.205411526https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXot1WiurY%253D&md5=4ee3951ff5bfe40aaeb405eaa7b1ca62Structure and electronic properties of Gen (n = 2-25) clusters from density-functional theoryWang, Jinlan; Wang, Guanghou; Zhao, JijunPhysical Review B: Condensed Matter and Materials Physics (2001), 64 (20), 205411/1-205411/5CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The geometrical and electronic structures of the germanium clusters with up to 25 atoms are studied by using d.-functional theory with the generalized gradient approxn. The Gen clusters follow a prolate growth pattern with n ≥ 13. For medium-sized clusters, we find two kinds of competing structures, stacked layered structures and compact structures. The stacked layered structures with capped tetrahedron Ge9 cluster are more stable than compact structures and other stacked structures. The size dependence of cluster binding energies, highest-occupied and lowest-unoccupied MO gap, and ionization potentials are discussed and compared with expts.
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527Bulusu, S.; Yoo, S.; Zeng, X. C. Search for global minimum geometries for medium sized germanium clusters: Ge12–Ge20. J. Chem. Phys. 2005, 122, 164305, DOI: 10.1063/1.1883647527https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXksFKhs70%253D&md5=bd5a0cc301aeab156bdeed28a62fee8aSearch for global minimum geometries for medium sized germanium clusters: Ge12-Ge20Bulusu, S.; Yoo, S.; Zeng, X. C.Journal of Chemical Physics (2005), 122 (16), 164305/1-164305/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We performed an unbiased search for the global min. geometries of small-to-medium sized germanium clusters Gen(12≤n≤18) as well as a biased search (using seeding method) for Gen(17≤n≤20). We employed the basin-hopping algorithm coupled with the plane-wave pseudopotential d. functional calcns. For each size, we started the unbiased search with using several structurally very different initial clusters, or we started the biased search with three different seeds. Irresp. of the initial structures of clusters we found that the obtained lowest-energy clusters of the size n = 12-16 and 18 are the same. Among them, the predicted global min. of Gen(12≤n≤16) are identical to those reported previously [Shvartsburg et al., Phys. Rev. Lett. 83, 167 (1999)]. For n = 17-20, we identified two or three nearly isoenergetic low-lying isomers (for each size) that compete for the global min. Nearly all the low-lying clusters in the size range of 12≤n≤20 contain the tri-capped trigonal prism motif and are all prolate in geometry, in agreement with the expt.
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528Kumar, V.; Kawazoe, Y. Metal-encapsulated icosahedral superatoms of germanium and tin with large gaps: Zn@Ge12 and Cd@Sn12. Appl. Phys. Lett. 2002, 80, 859– 861, DOI: 10.1063/1.1447315528https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xpt1emtQ%253D%253D&md5=b0bdb60c8de1a3644bfdab52feac1752Metal-encapsulated icosahedral superatoms of germanium and tin with large gaps: Zn@Ge12 and Cd@Sn12Kumar, Vijay; Kawazoe, YoshiyukiApplied Physics Letters (2002), 80 (5), 859-861CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Metal (M)-encapsulated clusters of Ge and Sn, Zn@Ge12 and Cd@Sn12, are obtained from total energy calcns. using ab initio pseudopotential plane wave method and generalized gradient approxn. for the exchange-correlation energy. These have perfect icosahedral symmetry and large highest occupied-LUMO gap of ∼2 eV. It lies in the optical region and makes these species attractive for cluster assembled optoelectronic materials. Calcns. on Si clusters doped with Be show a different behavior.
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529Singh, A. K.; Kumar, V.; Kawazoe, Y. Thorium encapsulated caged clusters of germanium: Th@Gen, n = 16, 18, and 20. J. Phys. Chem. B 2005, 109, 15187– 15189, DOI: 10.1021/jp053169d529https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmsFWntb0%253D&md5=b006d0b5a9eb1b59eb0f25512d9e54deThorium Encapsulated Caged Clusters of Germanium: Th@Gen, n = 16, 18, and 20Singh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiJournal of Physical Chemistry B (2005), 109 (32), 15187-15189CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)We report from ab initio calcns. that thorium encapsulation can be used to stabilize highly sym. cages of germanium with 16 and 20 atoms. The lowest energy structures of these clusters are different from the recently found silicon fullerenes and are similar to clusters found in bulk metallic alloys. The binding energies of these clusters are higher compared with the values for the elemental germanium clusters of comparable sizes, and this suggests a strong possibility of their exptl. realization in large quantities. Also, Th@Ge16 has a large highest occupied-LUMO (HOMO-LUMO) gap of 1.72 eV that makes it interesting for optoelectronic applications.
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530Zhang, X.; Li, G.; Gao, Z. Laser ablation of Co/Ge mixtures: A new type of endohedral structure, a semiconductor cage trapping a metal atom. Rapid Commun. Mass Spectrom. 2001, 15, 1573– 1576, DOI: 10.1002/rcm.408530https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXntFWntrs%253D&md5=eacf7acdc0e12d0aad4220f1be136a93Laser ablation of Co/Ge mixtures: a new type of endohedral structure, a semiconductor cage trapping a metal atomZhang, Xia; Li, Guoliang; Gao, ZhenRapid Communications in Mass Spectrometry (2001), 15 (17), 1573-1576CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)In expts. on Co/Ge binary clusters by laser vaporization, a remarkably strong signal in the mass spectrum was presented, which was assigned to the cluster anion consisting of ten Ge atoms and one Co atom, [CoGe10]-. For this cluster anion the authors suggest an endohedral structure - a Ge10 cage trapping a Co atom in its interior. Reactions between Co clusters and Ge clusters using a laser double ablation reactor also confirmed the endohedral structure. According to the electronic and geometrical shell closures, a bicapped tetragonal antiprism structure was predicted for this endohedral [CoGe10]- cluster anion.
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531Atobe, J.; Koyasu, K.; Furuse, S.; Nakajima, A. Anion photoelectron spectroscopy of germanium and tin clusters containing a transition-or lanthanide-metal atom; MGen– (n = 8–20) and MSnn– (n = 15–17)(M = Sc–V, Y–Nb, and Lu–Ta). Phys. Chem. Chem. Phys. 2012, 14, 9403– 9410, DOI: 10.1039/c2cp23247b531https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XosVWltrY%253D&md5=64d4a88016061ed3bb73c5903c87594dAnion photoelectron spectroscopy of germanium and tin clusters containing a transition- or lanthanide-metal atom; MGen- (n = 8-20) and MSnn- (n = 15-17) (M = Sc-V, Y-Nb, and Lu-Ta)Atobe, Junko; Koyasu, Kiichirou; Furuse, Shunsuke; Nakajima, AtsushiPhysical Chemistry Chemical Physics (2012), 14 (26), 9403-9410CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The electronic properties of Ge and Sn clusters contg. a transition- or lanthanide-metal atom from Group 3, 4, or 5, MGen (M = Sc, Ti, V, Y, Zr, Nb, Lu, Hf, and Ta) and MSnn (M = Sc, Ti, Y. Zr, and Hf), were studied by anion photoelectron spectroscopy at 213 nm. In the case of the group 3 elements Sc, Y, and Lu, the threshold energy of electron detachment of MGen- exhibits local max. at n = 10 and 16, while in the case of the group 4 elements Ti, Zr, and Hf, it exhibits a local min. only at n = 16, assocd. with the presence of a small bump in the spectrum. A similar behavior is obsd. for MSnn- around n = 16, and these electronic characteristics of MGen and MSnn are closely related to those of MSin. Compared to MSin, however, the larger cavity size of a Gen cage allows metal atom encapsulation at a smaller size n. A cooperative effect between the electronic and geometric structures of clusters with a large cavity of Ge16 or Sn16 is discussed together with the results of expts. that probe their geometric stability via their reactivity to H2O adsorption.
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532Deng, X. J.; Kong, X. Y.; Xu, X. L.; Xu, H. G.; Zheng, W. J. Structural and magnetic properties of CoGen– (n = 2–11) clusters: Photoelectron spectroscopy and density functional calculations. ChemPhysChem 2014, 15, 3987– 3993, DOI: 10.1002/cphc.201402615532https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVCrsbfI&md5=f20c13349b9f3b6810f9b9870d00180dStructural and Magnetic Properties of CoGen- (n=2-11) Clusters: Photoelectron Spectroscopy and Density Functional CalculationsDeng, Xiao-Jiao; Kong, Xiang-Yu; Xu, Xi-Ling; Xu, Hong-Guang; Zheng, Wei-JunChemPhysChem (2014), 15 (18), 3987-3993CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)A series of cobalt-doped germanium clusters, CoGen-/0 (n = 2-11), are investigated by using anion photoelectron spectroscopy combined with d. functional theory calcns. For both anionic and neutral CoGen (n = 2-11) clusters, the crit. size of the transition from exo- to endohedral structures is n = 9. Natural population anal. shows that there is electron transfer from the Gen framework to the Co atom at n = 7-11 for both anionic and neutral CoGen clusters. The magnetic moments of the anionic and neutral CoGen clusters decrease to the lowest values at n = 10 and 11. The transfer of electrons from the Gen framework to the Co atom and the minimization of the magnetic moments are related to the evolution of CoGen structures from exo- to endohedral.
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533Deng, X.-J.; Kong, X.-Y.; Xu, H.-G.; Xu, X.-L.; Feng, G.; Zheng, W.-J. Photoelectron spectroscopy and density functional calculations of VGen– (n = 3–12) clusters. J. Phys. Chem. C 2015, 119, 11048– 11055, DOI: 10.1021/jp511694c533https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFyhtLfL&md5=1e5c4f9d4d78c8b19233d6fb0f7d4403Photoelectron Spectroscopy and Density Functional Calculations of VGen- (n = 3-12) ClustersDeng, Xiao-Jiao; Kong, Xiang-Yu; Xu, Hong-Guang; Xu, Xi-Ling; Feng, Gang; Zheng, Wei-JunJournal of Physical Chemistry C (2015), 119 (20), 11048-11055CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structural, electronic and magnetic properties of VGen-/0(n = 3-12) clusters were investigated using anion photoelectron spectroscopy in combination with d. functional theory calcns. We found that the dominant geometries are exohedral for the VGen-/0 clusters with n ≤ 7. The VGe8-/0 clusters have half-encapsulated boat-shaped structures, and the opening of the boat-shaped structure is gradually covered by the addnl. Ge atoms to form Gen cage from n = 9-11. At n = 12, a D3d distorted hexagonal prism cage structure is formed. According to the natural population anal., for both anionic and neutral VGen clusters of n = 8-12, there is electron transfer from the Gen framework to the V atom and the total magnetic moments decrease to the min. The electron transfer pattern and the minimization of the magnetic moments for these clusters are related to their structural evolution.
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534Jin, Y.; Lu, S.; Hermann, A.; Kuang, X.; Zhang, C.; Lu, C.; Xu, H.; Zheng, W. Probing the structural evolution of ruthenium doped germanium clusters: Photoelectron spectroscopy and density functional theory calculations. Sci. Rep. 2016, 6, 30116, DOI: 10.1038/srep30116534https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXksFehs7o%253D&md5=d057a051edd65d6cbbf4ccff011df6e2Probing the structural evolution of ruthenium doped germanium clusters: Photoelectron spectroscopy and density functional theory calculationsJin, Yuanyuan; Lu, Shengjie; Hermann, Andreas; Kuang, Xiaoyu; Zhang, Chuanzhao; Lu, Cheng; Xu, Hongguang; Zheng, WeijunScientific Reports (2016), 6 (), 30116CODEN: SRCEC3; ISSN:2045-2322. (Nature Publishing Group)A review. We present a combined exptl. and theor. study of ruthenium doped germanium clusters, RuGen- (n = 3-12), and their corresponding neutral species. Photoelectron spectra of RuGen- clusters are measured at 266 nm. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) are obtained. Unbiased CALYPSO structure searches confirm the low-lying structures of anionic and neutral ruthenium doped germanium clusters in the size range of 3 ≤ n ≤ 12. Subsequent geometry optimizations using d. functional theory (DFT) at PW91/LANL2DZ level are carried out to det. the relative stability and electronic properties of ruthenium doped germanium clusters. It is found that most of the anionic and neutral clusters have very similar global features. Although the global min. structures of the anionic and neutral clusters are different, their resp. geometries are obsd. as the low-lying isomers in either case. In addn., for n > 8, the Ru atom in RuGen-/0 clusters is absorbed endohedrally in the Ge cage. The theor. predicted vertical and adiabatic detachment energies are in good agreement with the exptl. measurements. The excellent agreement between DFT calcns. and expt. enables a comprehensive evaluation of the geometrical and electronic structures of ruthenium doped germanium clusters.
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535Lu, S.-J.; Hu, L.-R.; Xu, X.-L.; Xu, H.-G.; Chen, H.; Zheng, W.-J. Transition from exohedral to endohedral structures of AuGen– (n = 2–12) clusters: Photoelectron spectroscopy and ab initio calculations. Phys. Chem. Chem. Phys. 2016, 18, 20321– 20329, DOI: 10.1039/C6CP00373G535https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XkvVSis7g%253D&md5=679da50e3cfa60b16278110b0a0fa20aTransition from exohedral to endohedral structures of AuGen- (n = 2-12) clusters: photoelectron spectroscopy and ab initio calculationsLu, Sheng-Jie; Hu, Lian-Rui; Xu, Xi-Ling; Xu, Hong-Guang; Chen, Hui; Zheng, Wei-JunPhysical Chemistry Chemical Physics (2016), 18 (30), 20321-20329CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Gold-doped germanium clusters, AuGen- (n = 2-12), were investigated by using anion photoelectron spectroscopy in combination with ab initio calcns. Their geometric structures were detd. by comparison of the theor. calcns. with the exptl. results. The results show that the most stable isomers of AuGen- with n = 2-10 are all exohedral structures with the Au atom capping the vertex, edge or face of Gen clusters, while AuGe11- is found to be the crit. size of the endohedral structure. Interestingly, AuGe12- has an Ih sym. icosahedral structure with the Au atom located at the center. The MO anal. of the AuGe12- cluster suggests that the interactions between the 5d orbitals of the Au atom and the 4s4p hybridized orbitals of the Ge atoms may stabilize the Ih sym. icosahedral cage and promote the Au atom to be encapsulated in the cage of Ge12. The NICS(0) and NICS(1) values are calcd. to be -143.7 ppm and -36.3 ppm, resp., indicating that the icosahedral AuGe12- cluster is significantly arom.
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536Deng, X.-j.; Kong, X.-y.; Xu, X.-l.; Xu, H.-g.; Zheng, W.-j. Photoelectron spectroscopy and density functional calculations of TiGen– (n = 7–12) clusters. Chin. J. Chem. Phys. 2016, 29, 123– 128, DOI: 10.1063/1674-0068/29/cjcp1511232536https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XkvVCisbs%253D&md5=dafe82a8df9fff5699f6bce3d1a63bfdPhotoelectron Spectroscopy and Density Functional Calculations of TiGen- (n=7-12) ClustersDeng, Xiao-jiao; Kong, Xiang-yu; Xu, Xi-ling; Xu, Hong-guang; Zheng, Wei-junChinese Journal of Chemical Physics (2016), 29 (1), 123-128CODEN: CJCPA6; ISSN:1674-0068. (Chinese Physical Society)The growth pattern and electronic properties of TiGen- (n=7-12) clusters were investigated using anion photoelectron spectroscopy and d. functional theory calcns. For both anionic and neutral TiGen clusters, a half-encapsulated boat-shaped structure appears at n=8, and the boat-shaped structure is gradually covered by the addnl. Ge atoms to form Gen cage at n=9-11. TiGe12- cluster has a distorted hexagonal prism cage structure. According to the natural population anal., the electron transfers from the Gen framework to the Ti atom for TiGen-/0 clusters at n=8-12, implying that the electron transfer pattern is related to the structural evolution.
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537Deng, X.-J.; Kong, X.-Y.; Liang, X.; Yang, B.; Xu, H.-G.; Xu, X.-L.; Feng, G.; Zheng, W.-J. Structural and magnetic properties of FeGen–/0 (n = 3-12) clusters: Mass-selected anion photoelectron spectroscopy and density functional theory calculations. J. Chem. Phys. 2017, 147, 234310, DOI: 10.1063/1.5000886537https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVejsLnL&md5=8868a9d2d23dd94d7a1988a2b1ab8fbcStructural and magnetic properties of FeGen-/0 (n = 3-12) clusters: Mass-selected anion photoelectron spectroscopy and density functional theory calculationsDeng, Xiao-Jiao; Kong, Xiang-Yu; Liang, Xiaoqing; Yang, Bin; Xu, Hong-Guang; Xu, Xi-Ling; Feng, Gang; Zheng, Wei-JunJournal of Chemical Physics (2017), 147 (23), 234310/1-234310/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structural, electronic, and magnetic properties of FeGen-/0 (n = 3-12) clusters were investigated by using anion photoelectron spectroscopy in combination with DFT-B3PW91 method. For both anionic and neutral FeGen (n = 3-12) clusters with n ≤ 7, the dominant structures are exohedral. The FeGe8-/0 clusters have half-encapsulated boat-shaped structures, and the opening of the boat-shaped structure is gradually covered by the addnl. Ge atoms to form Gen cage from n = 9 to 11. The structures of FeGe10-/0 can be viewed as two Ge atoms sym. capping the opening of the boat-shaped structure of FeGe8, and those of FeGe12-/0 are distorted hexagonal prisms with the Fe atom at the center. Natural population anal. shows that there is an electron transfer from the Ge atoms to the Fe atom at n = 8-12. The total magnetic moment of FeGen-/0 and local magnetic moment of the Fe atom have not been quenched. (c) 2017 American Institute of Physics.
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538Liang, X.-Q.; Deng, X.-J.; Lu, S.-J.; Huang, X.-M.; Zhao, J.-J.; Xu, H.-G.; Zheng, W.-J.; Zeng, X. C. Probing structural, electronic, and magnetic properties of iron-doped semiconductor clusters Fe2Gen–/0 (n = 3–12) via joint photoelectron spectroscopy and density functional study. J. Phys. Chem. C 2017, 121, 7037– 7046, DOI: 10.1021/acs.jpcc.7b00943538https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjs1Kmt78%253D&md5=19b8082bd592d59f0aa819b325eb8a3dProbing Structural, Electronic, and Magnetic Properties of Iron-Doped Semiconductor Clusters Fe2Gen-/0 (n = 3-12) via Joint Photoelectron Spectroscopy and Density Functional StudyLiang, Xiao-Qing; Deng, Xiao-Jiao; Lu, Sheng-Jie; Huang, Xiao-Ming; Zhao, Ji-Jun; Xu, Hong-Guang; Zheng, Wei-Jun; Zeng, Xiao ChengJournal of Physical Chemistry C (2017), 121 (12), 7037-7046CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The authors present a joint exptl. and theor. study on double Fe atom doped Ge clusters, Fe2Gen-/0 (n = 3-12). The exptl. photoelectron spectra of cluster anions are reasonably reproduced by theor. simulations. The low-lying structures of the Fe-doped semiconductor clusters are obtained by using an ab initio computation-based genetic-algorithm global optimization method. The smaller-sized Fe2Gen- (n = 3-8) clusters adopt bipyramid-based geometries, while the larger ones (n ≥ 9) adopt polyhedral cage-like structures with 1 interior Fe atom. Starting from n = 8, the most stable anionic clusters Fe2Gen- exhibit structures that are different from that of their neutral counterparts Fe2Gen. Robust ferromagnetic interaction is found between the 2 doped Fe atoms in the neutral clusters Fe2Gen, while the total spin moment always remains at 4 μB for all the neutral double Fe atom doped Ge clusters up to n = 12. This behavior is in Stark contrast to the magnetic quenching behavior typically obsd. in Ge clusters doped with a single Fe atom.
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539Liang, X.; Kong, X.; Lu, S.-J.; Huang, Y.; Zhao, J.; Xu, H.-G.; Zheng, W.; Zeng, X. C. Structural evolution and magnetic properties of anionic clusters Cr2Gen (n = 3–14): Photoelectron spectroscopy and density functional theory computation. J. Phys.: Condens. Matter 2018, 30, 335501, DOI: 10.1088/1361-648X/aad2bf539https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvFKrtL%252FM&md5=cadb0b1cca75198f0d0b9182819edf50Structural evolution and magnetic properties of anionic clusters Cr2Gen (n = 3 - 14): photoelectron spectroscopy and density functional theory computationLiang, Xiaoqing; Kong, Xiangyu; Lu, Sheng-Jie; Huang, Yingying; Zhao, Jijun; Xu, Hong-Guang; Zheng, Weijun; Zeng, Xiao ChengJournal of Physics: Condensed Matter (2018), 30 (33), 335501/1-335501/11CODEN: JCOMEL; ISSN:0953-8984. (IOP Publishing Ltd.)Structural, electronic, and magnetic properties of Cr2Gen- clusters were investigated by using photoelectron spectroscopy and DFT-PBE method using genetic algorithm optimization. For Cr2Gen- with n ≤ 8, the cluster have bipyramid-based structures. Cr2Ge9- cluster has an opening in its cage-like structure; for n = 10 to 14 this structure is gradually covered by addnl. Ge atoms to form closed-cage configuration with one interior Cr atom. The two Cr atoms in Cr2Gen- clusters tend to form a Cr-Cr bond rather than to be sepd. Interestingly, the magnetic moment of all anionic clusters considered is 1 μB. Almost all clusters exhibit antiferromagnetic Cr-Cr coupling, except for two clusters, Cr2Ge5- and Cr2Ge6. To the best of our knowledge, the Cr2Gen- clusters are the first kind of transition-metal doped semiconductor clusters that exhibit relatively stable antiferromagnetism within a wide size range. The exptl./theor. results suggest high potential to modify the magnetic behavior of semiconductor clusters through introducing different transition-metal dopant atoms.
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540Goicoechea, J. M.; Sevov, S. C. [(Pd–Pd)@Ge18]4-: A palladium dimer inside the largest single-cage deltahedron. J. Am. Chem. Soc. 2005, 127, 7676– 7677, DOI: 10.1021/ja051224q540https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvVehs70%253D&md5=c8839d8168f2b6932f2a90cc54fd08e0[(Pd-Pd)@Ge18]4-: A Palladium Dimer Inside the Largest Single-Cage DeltahedronGoicoechea, Jose M.; Sevov, Slavi C.Journal of the American Chemical Society (2005), 127 (21), 7676-7677CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The largest single-cage deltahedral cluster is made of 18 germanium atoms and is centered by a pair of palladium atoms. Its shape is very close to the ideal D3d symmetry expected and predicted for a cluster of this size.
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541Zhou, B.; Denning, M. S.; Kays, D. L.; Goicoechea, J. M. Synthesis and isolation of [Fe@Ge10]3–: A pentagonal prismatic zintl ion cage encapsulating an interstitial iron atom. J. Am. Chem. Soc. 2009, 131, 2802– 2803, DOI: 10.1021/ja900055j541https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFWns7Y%253D&md5=741a5ecf963fa530134de0595ad8a049Synthesis and Isolation of [Fe@Ge10]3-: A Pentagonal Prismatic Zintl Ion Cage Encapsulating an Interstitial Iron AtomZhou, Binbin; Denning, Mark S.; Kays, Deborah L.; Goicoechea, Jose M.Journal of the American Chemical Society (2009), 131 (8), 2802-2803CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Reaction of an ethylenediamine (en) soln. of the Zintl phase precursor K4Ge9 with FeAr2 (Ar = 2,6-Mes2C6H3) in the presence of 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) yielded the endohedral Zintl ion [Fe@Ge10]3- (1) which was crystallog. characterized as a [K(2,2,2-crypt)]+ salt in [K(2,2,2-crypt)]3[Fe@Ge10]•2en. This unprecedented Zintl ion exhibits a pentagonal prismatic 10-atom Ge cage with an interstitial Fe atom in the central cavity. Confirmation of the existence of the cluster anion in soln. was corroborated by pos. and neg. ion mode electrospray mass spectrometry.
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542Wang, J. Q.; Stegmaier, S.; Fässler, T. F. [Co@Ge10]3–: An intermetalloid cluster with Archimedean pentagonal prismatic structure. Angew. Chem., Int. Ed. 2009, 48, 1998– 2002, DOI: 10.1002/anie.200805511542https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjsFaksrc%253D&md5=19c33326dbb02761385c9a6e4a2479cf[Co@Ge10]3-: an intermetalloid cluster with Archimedean pentagonal prismatic structureWang, Jian-Qiang; Stegmaier, Saskia; Fassler, Thomas F.Angewandte Chemie, International Edition (2009), 48 (11), 1998-2002CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The unusual structure of [Co@Ge10]3-, which was obtained by the reaction of K4Ge9 with [Co(C8H12)(C8H13)] in ethylenediamine, raises questions about chem. bonding in the anion. The Zintl ion cluster has virtual Dsh symmetry and is a unique example of a ligand-free cluster that is not a deltahedron. The optimized geometry (DFT calcns.) and delocalized chem. bonding are discussed.
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543Espinoza-Quintero, G.; Duckworth, J. C.; Myers, W. K.; McGrady, J. E.; Goicoechea, J. M. Synthesis and characterization of [Ru@Ge12]3–: An endohedral 3-connected cluster. J. Am. Chem. Soc. 2014, 136, 1210– 1213, DOI: 10.1021/ja411280v543https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXksVKh&md5=d2f1fba93f171f833265d078fb6aea8cSynthesis and Characterization of [Ru@Ge12]3-: An Endohedral 3-Connected ClusterEspinoza-Quintero, Gabriela; Duckworth, Jack C. A.; Myers, William K.; McGrady, John E.; Goicoechea, Jose M.Journal of the American Chemical Society (2014), 136 (4), 1210-1213CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The 12-vertex endohedral cluster [Ru@Ge12]3- reveals an unprecedented D2d-sym. 3-connected polyhedral geometry. The structure contrasts dramatically with the known deltahedral or approx. deltahedral geometries of [M@Pb12]2- (M = Ni, Pd, Pt) and [Mn@Pb12]3- and is a result of extensive delocalization of electron d. from the transition-metal center onto the cage.
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544Li, G.; Zhang, X.; Tang, Z.; Gao, Z. Theoretical studies on the structure of the endohedral CoGe10– cluster anion. Chem. Phys. Lett. 2002, 359, 203– 212, DOI: 10.1016/S0009-2614(02)00736-4544https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XksVemt7c%253D&md5=f70c5d3a0b13b201edd02731eceff537Theoretical studies on the structure of the endohedral CoGe10- cluster anionLi, Guoliang; Zhang, Xia; Tang, Zichao; Gao, ZhenChemical Physics Letters (2002), 359 (3,4), 203-212CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)The structure was studied of the endohedral CoGe10- cluster anion using ab initio (HF) and d. functional theory (DFT-B3LYP) methods in conjunction with effective core potential basis sets (LanL2DZ and LanL2DZ*). For the important structures, all-electron basis sets plus polarization and diffuse functions (6-31+G*) were used. The bicapped tetragonal antiprism structure with D4d symmetry is the most stable. Compared with the fragments [Co+Ge10-(D4d)], this structure is 97.7 kcal/mol more stable at the B3LYP/LanL2DZ level. Other low-energy structures were also optimized.
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545Lu, J.; Nagase, S. Metal-doped germanium clusters MGens at the sizes of n = 12 and 10: Divergence of growth patterns from the MSin clusters. Chem. Phys. Lett. 2003, 372, 394– 398, DOI: 10.1016/S0009-2614(03)00415-9545https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjtFWksbg%253D&md5=d3e1e17950179dff51ae15496c03128fMetal-doped germanium clusters MGens at the sizes of n=12 and 10: divergence of growth patterns from the MSin clustersLu, Jing; Nagase, ShigeruChemical Physics Letters (2003), 372 (3,4), 394-398CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Structural and electronic properties of the metal-doped germanium clusters MGen (M = Hf, W, Os, Ni, and Zn) in the sizes of n = 12 and 10 are investigated via d. functional theory calcns. based on the hybrid exchange-correlation energy. Their growth patterns are found different from those of the MSin clusters although the pure Gen and Sin clusters have identical geometries in the two sizes. The MGe12 (M = W and Os) and ZnGe12 clusters, with an endohedral distorted hexagonal prismatic and an endohedral perfect icosahedral structure, resp., show higher chem. stability among these checked MGen clusters. This makes them attractive for cluster-assembled materials.
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546Wang, J.; Han, J.-G. A computational investigation of copper-doped germanium and germanium clusters by the density-functional theory. J. Chem. Phys. 2005, 123, 244303, DOI: 10.1063/1.2148949546https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xit1ersQ%253D%253D&md5=5ef77a0b7149f8a070640e27dbbd4836A computational investigation of copper-doped germanium and germanium clusters by the density-functional theoryWang, Jin; Han, Ju-GuangJournal of Chemical Physics (2005), 123 (24), 244303/1-244303/12CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometries, stabilities, and electronic properties of Gen and CuGen (n=2-13) clusters have been systematically investigated by using d.-functional approach. According to optimized CuGen geometries, growth patterns of Cu-capped Gen or Cu-substituted Gen+1 clusters for the small- or middle-sized CuGen clusters as well as growth patterns of Cu-concaved Gen or Ge-capped CuGen-1 clusters for the large-sized CuGen clusters are apparently dominant. The av. at. binding energies and fragmentation energies are calcd. and discussed; particularly, the relative stabilities of CuGe10 and Ge10 are the strongest among all different sized CuGen and Gen clusters, resp. These findings are in good agreement with the available exptl. results on CoGe10- and Ge10 clusters. Consequently, unlike some transition metal (TM)Si12, the hexagonal prism CuGe12 is only low-lying structure; however, the basketlike structure is located as the lowest-energy structure. Different from some TM-doped silicon clusters, charge always transfers from copper to germanium atoms in all different sized clusters. Furthermore, the calcd. HOMO and LUMO (HOMO-LUMO) gaps are obviously decreased when Cu is doped into the Gen clusters, together with the decrease of HOMO-LUMO gaps, as the size of clusters increases. Addnl., the contribution of the doped Cu atom to bond properties and polarizabilities of the Gen clusters is also discussed.
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547Wang, J.; Han, J.-G. A theoretical study on growth patterns of Ni-doped germanium clusters. J. Phys. Chem. B 2006, 110, 7820– 7827, DOI: 10.1021/jp0571675547https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XivVOktrs%253D&md5=eca48c850dce0f72fdbc311a18f5893aA Theoretical Study on Growth Patterns of Ni-Doped Germanium ClustersWang, Jin; Han, Ju-GuangJournal of Physical Chemistry B (2006), 110 (15), 7820-7827CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)Ni-doped germanium clusters have been systematically investigated by using the d. functional approach. The growth-pattern behaviors, stabilities, charge transfer, and polarities of these clusters are discussed in detail. Obviously different growth patterns appear between small-sized Ni-doped germanium clusters and middle- or larger-sized Ni-doped germanium clusters. The Ni-convex or substituted Gen frames for small-sized clusters as well as Ni-concaved or encapsulated Gen frames for middle- or large-sized clusters are dominant growth patterns. The calcd. fragmentation energies manifest that the magic nos. of stabilities are 5, 8, 10, and 13 for Ni-doped germanium clusters; the obtained relative stabilities exhibit that the Ni-encapsulated Ge10 cluster is the most stable species of all different-sized clusters, which is in good agreement with available exptl. observations of CoGe10-. Natural population anal. shows that different charge-transfer phenomena depend on the sizes of the Ni-doped Gen clusters. Addnl., the properties of frontier orbitals and the polarities of Ni-doped Gen clusters are also discussed.
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548Wang, J.; Han, J.-G. Geometries and electronic properties of the tungsten-doped germanium clusters: WGen (n = 1–17). J. Phys. Chem. A 2006, 110, 12670– 12677, DOI: 10.1021/jp0636219548https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtFertrbL&md5=101690b316299735e2327733b33c1e45Geometries and Electronic Properties of the Tungsten-Doped Germanium Clusters: WGen (n = 1-17)Wang, Jin; Han, Ju-GuangJournal of Physical Chemistry A (2006), 110 (46), 12670-12677CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Geometries assocd. with relative stabilities, energy gaps, and polarities of W-doped germanium clusters have been investigated systematically by using d. functional theory. The threshold size for the endohedral coordination and the crit. size of W-encapsulated Gen structures emerge as, resp., n = 8 and n = 12, while the fullerene-like W@Gen clusters appears at n = 14. The evaluated relative stabilities in term of the calcd. fragmentation energies reveal that the fullerene-like W@Ge14 and W@Ge16 structures as well as the hexagonal prism WGe12 have enhanced stabilities over their neighboring clusters. Furthermore, the calcd. polarities of the W@Gen reveal that the bicapped tetragonal antiprism WGe10 is a polar mol. while the hexagonal prism WGe12 is a nonpolar mol. Moreover, the recorded natural populations show that the charges transfer from the germanium framework to the W atom. Addnl., the WGe12 cluster with large HOMO-LUMO (HOMO-LUMO) gap, large fragmentation energy, and large binding energy is supposed to be suitable as a building block of assembly cluster material. It should be pointed out that the remarkable features of W@Gen clusters above are distinctly different from those of transition metal (TM) doped Gen (TM = Cu and Ni) clusters, indicating that the growth pattern of the TMGen depends on the kind of doped TM impurity.
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549Wang, J.; Han, J.-G. The growth behaviors of the Zn-doped different sized germanium clusters: A density functional investigation. Chem. Phys. 2007, 342, 253– 259, DOI: 10.1016/j.chemphys.2007.10.008549https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlOmt7vE&md5=722704f855c249794df2ab6fa36e022cThe growth behaviors of the Zn-doped different sized germanium clusters: A density functional investigationWang, Jin; Han, Ju-GuangChemical Physics (2007), 342 (1-3), 253-259CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)The growth of Zn-doped germanium clusters, ZnGen (n = 1-13) was investigated by the DFT-(U)B3LYP method. The growth patterns, relative stabilities, charge transfers, HOMO-LUMO gaps and polarities of these clusters are discussed in detail. The threshold size of the Gen clusters in order to encapsulate Zn atom is n = 10; the icosahedral ZnGe12 cluster shows the highest relative stability as compared to other clusters, which differs from the results for clusters doped by first-row transition metals. The calcd. fragmentation energies detd. the magic nos. of relative stabilities for the Zn-doped germanium clusters: n = 5, 9, and 12. Natural population analyses show charge transfer from Zn to Ge framework. The HOMO-LUMO gap of the icosahedral ZnGe12 is remarkably large (3.159 eV) in comparison with caged ZnGen clusters (n = 1-11, 13).
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550Jing, Q.; Tian, F.-y.; Wang, Y.-x. No quenching of magnetic moment for the GenCo (n = 1–13) clusters: First-principles calculations. J. Chem. Phys. 2008, 128, 124319, DOI: 10.1063/1.2898880550https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXktl2ntr4%253D&md5=671f75e74fcec57c5823e7d8d9d1d327No quenching of magnetic moment for the GenCo (n = 1-13) clusters: First-principles calculationsJing, Qun; Tian, Fu-yang; Wang, Yuan-xuJournal of Chemical Physics (2008), 128 (12), 124319/1-124319/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The authors predict that for the GenCo (n = 1-13) clusters the magnetic moment does not quench, which is dark contrast to the previous results with transition-metal-doped Sin clusters. It may be due to the unpaired electrons of the Co atom in the clusters. For the ground state structures of the GenCo (n ≥ 9) clusters, the Co atom completely falls into the center of the Ge outer frame, forming metal-encapsulated Gen cages. The doping of the Co atom enhances the stability of the host Gen clusters. The Ge10Co cluster with the bicapped tetragonal antiprism structure is more stable than others, which agrees very well with the results of the expt. of the Co/Ge binary clusters by the laser vaporization. (c) 2008 American Institute of Physics.
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551Wang, J.; Ma, L.; Zhao, J.; Wang, G. Structural growth sequences and electronic properties of manganese-doped germanium clusters: MnGen (2–15). J. Phys.: Condens. Matter 2008, 20, 335223, DOI: 10.1088/0953-8984/20/33/335223551https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtFCgsL%252FI&md5=cbe28ec40626373b03de3d79299e7f10Structural growth sequences and electronic properties of manganese-doped germanium clusters: MnGen (n = 2-15)Wang, Jianguang; Ma, Li; Zhao, Jijun; Wang, GuanghouJournal of Physics: Condensed Matter (2008), 20 (33), 335223/1-335223/8CODEN: JCOMEL; ISSN:0953-8984. (Institute of Physics Publishing)The structural growth sequences and electronic properties of MnGen (n = 2-15) clusters have been investigated using d. functional theory (DFT) within the generalized gradient approxn. (GGA). An extensive search of the lowest-energy structures was conducted by considering a no. of structural isomers for each cluster size. In the ground-state structures of MnGen clusters, the equil. site of the Mn atom gradually moves from the convex, surface to interior sites as the Ge cluster size varies from 2 to 15. The threshold size for the formation of caged MnGen and the sealed Mn-encapsulated Gen structure is n = 9 and n = 10, resp. Maximum peaks were obsd. for MnGen clusters at n = 3, 6, 10, 12 and 14 with the size dependent on the second-order energy difference, implying that these clusters are relatively more stable. The electronic structures and magnetic properties of MnGen in the ground-state structures are discussed. The doped Mn atom makes the HOMO-LUMO gap of the Gen clusters smaller, due to hybridization between the p states of the Ge atom and the d states of the Mn atom. Most of the Mn-doped Gen clusters carry a magnetic moment of about 1.0 μB, except that MnGe6 and MnGe11 have a magnetic moment of about 3.0 μB. Charge transfer between Mn and Ge was also obsd.
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552Wang, J.; Han, J.-G. Geometries, stabilities, and vibrational properties of bimetallic Mo2-doped Gen (n = 9–15) clusters: A density functional investigation. J. Phys. Chem. A 2008, 112, 3224– 3230, DOI: 10.1021/jp710238t552https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXislels7o%253D&md5=7ca3a930037247a61f6d81dc12abe628Geometries, Stabilities, and Vibrational Properties of Bimetallic Mo2-Doped Gen (n = 9-15) Clusters: A Density Functional InvestigationWang, Jin; Han, Ju-GuangJournal of Physical Chemistry A (2008), 112 (14), 3224-3230CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Geometries of Mo2Gen clusters were studied by the DFT-B3LYP method. The relative stabilities, charge-transfer, and vibrational properties of these clusters are presented and discussed. The dominant geometries these clusters for n = 9-12 show one Mo atom inside a Ge cage and another Mo atom on the surface. The stable geometry of Mo2Ge9 cluster is analogous to that obsd. in recent expt.. The calcd. fragmentation energies and the relative stabilities demonstrate that the Mo2-doped Ge12 is the most stable structure. The crit. size of Mo2-encapsulated cage-like germanium clusters is n = 15. The largest energy gap and highest stability of Mo2Ge12 enable this species to be a unit for multiple metal Mo-doped germanium nanotubes. Vibrational mode analyses of Mo2Gen clusters demonstrate that the Mo-Mo stretching vibrations are sensitive to the geometries of the germanium frame, and that the point-group symmetry of germanium clusters affects the Mo-Mo stretching vibration relative to the IR inactive vibration.
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553Zhao, W.-J.; Wang, Y.-X. Geometries, stabilities, and electronic properties of FeGen (n = 9–16) clusters: Density-functional theory investigations. Chem. Phys. 2008, 352, 291– 296, DOI: 10.1016/j.chemphys.2008.07.006553https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGltrjE&md5=394a265dc7b3d22499e0c85d0ebd0230Geometries, stabilities, and electronic properties of FeGen (n=9-16) clusters: Density-functional theory investigationsZhao, Wen-Jie; Wang, Yuan-XuChemical Physics (2008), 352 (1-3), 291-296CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)Fe-doped germanium clusters have been systematically investigated by using the d.-functional approach. It was found that doping of one Fe atom contributes to strengthening the stability of the germanium framework. Maximum peaks of the fragmentation energies, the second-order energy differences, and the HOMO and LUMO (HOMO-LUMO) gaps were obsd. for clusters of sizes n = 9, 11, 13, 14, and 16, implying their relative higher stability than other-sized FeGe n clusters. In addn., the strongest stability of FeGe14 might stem from its highest symmetry (Oh). The HOMO-LUMO gaps are obviously reduced when the Fe atom is doped into the Gen clusters. We also found that charge always transfers from iron to germanium atoms in all sized FeGen clusters and the magnetic moment of the Fe atom does not quench when embedded in large-sized Gen (n = 10, 11, 12, and 16) clusters.
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554Wang, J.; Chen, X.; Liu, J. H. Investigation of a size-selective single hafnium-encapsulated germanium cage. J. Phys. Chem. A 2008, 112, 8868– 8876, DOI: 10.1021/jp804433d554https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVaitL%252FP&md5=3ccd30f478825d7635f1fc6911da9dafInvestigation of a Size-Selective Single Hafnium-Encapsulated Germanium CageWang, Jin; Chen, Xing; Liu, Jin HuaiJournal of Physical Chemistry A (2008), 112 (37), 8868-8876CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The structures, relative stabilities, and electronic properties of Hf@Gen clusters (n = 9-24) were calcd. by the DFT-B3LYP method. The dominant growth behavior of Hf@Gen is based on a pentagonal prism instead of a hexagonal prism. Analogous to Hf@Sin, the encapsulated fullerene-like structure of Hf@Gen begins to appear at n = 14, which is consistent with the prediction from the reactivity toward water in a recent expt. Also, similar to Hf@Sin in the previous exptl. observation, the binding energy of Hf@Gen increases gradually up to n = 16 and tends to get lower for n > 16 suggesting that stabilization of large germanium cages needs to be realized by doping with more Hf atoms. The Hf atom will obviously move away from the center of the cage for n > 20. According to anal. of the electron d. of size-selective Hf@Gen, the covalent character in the germanium framework can be affected by the encapsulated position of Hf. In addn., comparison between typical low-lying Hf@Gen and Hf@Sin cages (n = 12, 16 and 20) indicates that large-scaled divergence exists in stabilities, growth behaviors, electronic properties, and so forth.
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555Zhao, W.-J.; Wang, Y.-X. Geometries, stabilities, and magnetic properties of MnGen (n = 2–16) clusters: Density-functional theory investigations. J. Mol. Struct.: THEOCHEM 2009, 901, 18– 23, DOI: 10.1016/j.theochem.2008.12.039555https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjslOlsr8%253D&md5=d9ff27398e4c0372537ff58b65dc118fGeometries, stabilities, and magnetic properties of MnGen (n =2-16) clusters: Density-functional theory investigationsZhao, Wen-Jie; Wang, Yuan-XuJournal of Molecular Structure: THEOCHEM (2009), 901 (1-3), 18-23CODEN: THEODJ; ISSN:0166-1280. (Elsevier B.V.)Mn-doped germanium clusters have been systematically investigated by using the d.-functional approach. It was found that doping of one Mn atom contributes to strengthening the stability of the germanium framework. Maximum peaks of the second-order energy differences were obsd. for clusters of sizes n = 5, 9, 12, and 14, implying their relative higher stability than other-sized MnGen clusters. The HOMO and LUMO (HOMO-LUMO) gaps of the MnGen clusters, with the exception of MnGe14, are generally lower than the corresponding pure germanium clusters. We also found that charge always transfers from manganese to germanium atoms in all sized MnGen clusters and the magnetic moment of the Mn atom does not quench when embedded in all sized Gen (n = 2-16) clusters.
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556King, R. B.; Silaghi-Dumitrescu, I.; Uţă, M. M. Polyhedral structures with three-, four-, and five fold symmetry in metal-centered ten-vertex germanium clusters. Chem. - Eur. J. 2008, 14, 4542– 4550, DOI: 10.1002/chem.200701582556https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmslGhsLg%253D&md5=9a06779755233736f330d6b905196086Polyhedral structures with three-, four-, and five fold symmetry in metal-centered ten-vertex germanium clustersKing, R. Bruce; Silaghi-Dumitrescu, Ioan; Uta, Matei-MariaChemistry - A European Journal (2008), 14 (15), 4542-4550CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Studies using d. functional theory (DFT) at the hybrid B3LYP level indicate that the relative energies of structures with three-fold, four-fold, and five-fold symmetry for centered 10-vertex bare germanium clusters of the general type M@Ge10z depend on the central metal atom M and the skeletal electron count. For M@Ge10 clusters with 20 skeletal electrons the DFT results agree with exptl. data on the isoelectronic centered 10-vertex bare metal clusters. Thus the lowest energy structure for Ni@Ge10, isoelectronic with the known Ni@In1010-, is a C3v polyhedron derived from the tetracapped trigonal prism. However, Zn@Ge102+ is isoelectronic with the known cluster Zn@In108-, which has the lowest energy structure, a D4d bicapped square antiprism. For the clusters Ni@Ge102-, Cu@Ge10-, and Zn@Ge10 that have 22 skeletal electrons the lowest energy structures are the D4d bicapped square antiprism predicted by the Wade-Mingos rules. For the clusters Ni@Ge104-, Cu@Ge103-, and Zn@Ge102- that have 24 skeletal electrons the lowest energy structures are C3v polyhedra with 10 triangular faces and 3 quadrilateral faces derived from a tetracapped trigonal prism by extreme lengthening of the edges of the capped triangular face of the underlying trigonal prism. For the clusters Cu@Ge105-, and Zn@Ge104- that have 26 skeletal electrons the lowest energy structures are the D5d pentagonal antiprisms predicted by the Wade-Mingos rules and the C3v tetracapped trigonal prism as a somewhat higher energy structure. However, for the isoelectronic Ni@Ge106- the relative energies of these two structure types are reversed so that the C3v tetracapped trigonal prism becomes the global min. The effects of electron count on the geometries of the D5d pentagonal prism and D4d bicapped square antiprism centered metal cluster structures are consistent with the bonding/antibonding characteristics of the corresponding HOMO and LUMO frontier MOs.
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557King, R.; Silaghi-Dumitrescu, I.; Uta, M. Endohedral nickel, palladium, and platinum atoms in 10-vertex germanium clusters: Competition between bicapped square antiprismatic and pentagonal prismatic structures. J. Phys. Chem. A 2009, 113, 527– 533, DOI: 10.1021/jp8066074557https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFChsbvO&md5=7fa495ee887cbcb7fe84131f75770b37Endohedral Nickel, Palladium, and Platinum Atoms in 10-Vertex Germanium Clusters: Competition between Bicapped Square Antiprismatic and Pentagonal Prismatic StructuresKing, R. B.; Silaghi-Dumitrescu, I.; Uta, M. M.Journal of Physical Chemistry A (2009), 113 (3), 527-533CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)D. functional theory (DFT-B3LYP) predicts significant differences in the preferred structures of endohedral M@Ge10z (M = Ni, Pd, Pt; z = 0, 2-, 4-, 6-) clusters upon a change of the central metal atom in otherwise isoelectronic systems. For the neutral clusters M@Ge10 the global min. are singlet bicapped square antiprisms. However, triplet regular pentagonal prismatic structures become increasingly energetically competitive in the series Ni → Pd → Pt. The pentagonal prismatic dianions M@Ge102- (M = Ni, Pd, Pt) appear to have closed shell structures and are the global min. for palladium and platinum. However, the global min. for Ni@Ge102- is the capped square antiprism suggested by the Wade-Mingos rules. A no. of singlet low-energy unsym. structures are found for the tetraanions M@Ge104-. However, for the palladium and platinum tetraanions triplet pentagonal prismatic structures are energetically competitive with the unsym. structures.
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558Li, X.-J.; Su, K.-H. Structure, stability and electronic property of the gold-doped germanium clusters: AuGen (n = 2–13). Theor. Chem. Acc. 2009, 124, 345, DOI: 10.1007/s00214-009-0618-9558https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlKrtbrO&md5=d27f80292b76ce0aeb76521030dc2323Structure, stability and electronic property of the gold-doped germanium clusters: AuGe n (n = 2-13)Li, Xiao-Jun; Su, Ke-HeTheoretical Chemistry Accounts (2009), 124 (5-6), 345-354CODEN: TCACFW; ISSN:1432-881X. (Springer)The structure, stability and electronic property of the AuGe n (n = 2-13) clusters with different spin configurations are systematically investigated with d.-functional theory approach at UB3LYP/LanL2DZ level. In examg. the lowest energy structures, it is found that the growth behaviors for the small-sized AuGe n (n = 2-9) clusters and relatively large-sized AuGe n (n = 10-13) clusters are different. As the no. of Ge atom increases, the Au atom would gradually move from convex to surface and to interior sites. For the most stable structures of AuGe n (n = 10-13) clusters, the Au atom would be completely surrounded by the Ge atoms to form Au-encapsulated Ge n cages. Natural population anal. shows that the charges always transfer from the Au atom to the Ge n framework except for the AuGe2 cluster. This indicates that the Au atom acts as electron donor even the 5d orbitals of the Au atom are not significantly involved in chem. bonding. The analyses of the av. at. binding energies as well as the dissocn. energies and the second-order differences of total energy show that the AuGe n clusters with n = 5, 9 and 12 are more stable than their neighboring ones, in which the bicapped pentagonal prism AuGe12 in D 2d symmetry is most stable. The HOMO-LUMO gaps are explored to be in the region of semiconductors and the more stable clusters have slightly smaller gaps. It could be expected that the stable clusters might be considered as the novel building blocks in practical applications, e.g., the cluster-assembled semiconductors or optoelectronic material.
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559Bandyopadhyay, D.; Sen, P. Density functional investigation of structure and stability of Gen and GenNi (n = 1–20) clusters: Validity of the electron counting rule. J. Phys. Chem. A 2010, 114, 1835– 1842, DOI: 10.1021/jp905561n559https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFKnsg%253D%253D&md5=737cb0bcecd1bab634dcaf40a15fca85Density Functional Investigation of Structure and Stability of Gen and GenNi (n = 1-20) Clusters: Validity of the Electron Counting RuleBandyopadhyay, Debashis; Sen, PrasenjitJournal of Physical Chemistry A (2010), 114 (4), 1835-1842CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Structure and electronic properties of neutral and cationic pure and Ni-doped Ge clusters contg. 1-20 Ge atoms are calcd. within the framework of LCAO d. functional theory. It is found that in clusters contg. more than 8 Ge atoms the Ni atom is absorbed endohedrally in the Ge cage. Relative stability of Ni-doped clusters at different sizes is studied by calcg. their binding energy, embedding energy of a Ni atom in a Ge cluster, highest-occupied MO to lowest-unoccupied MO gap, and the second-order energy difference. Clusters having 20 valence electrons turn out to be relatively more stable in both the neutral and the cationic series. There is, in fact, a sharp drop in IP as the valence electron count increases from 20 to 21, in agreement with predictions of shell models. Relevance of these results to the designing of Ge-based superatoms is discussed.
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560Tai, T. B.; Nguyen, M. T. Lithium atom can be doped at the center of a germanium cage: The stable icosahedral Ge12Li– cluster and derivatives. Chem. Phys. Lett. 2010, 492, 290– 296, DOI: 10.1016/j.cplett.2010.04.072560https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXms1ynt74%253D&md5=fe2d730b3a7213c8ca03503eada029c8Lithium atom can be doped at the center of a germanium cage: The stable icosahedral Ge12Li- cluster and derivativesTai, Truong Ba; Nguyen, Minh ThoChemical Physics Letters (2010), 492 (4-6), 290-296CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Structure and stability of the Ge12Mx clusters with M = Li, Na, Be, Mg, B, Al, and x from -1 to +1, each contg. 50 valence electrons are investigated using DFT calcns. The global min. turn to be the high symmetry icosahedral structures, with large HOMO-LUMO gaps and high detachment or ionization energies. In particular, Li is found for the first time to be located at the center of an icosahedron Ge12Li-. The high thermodn. stability of the icosahedra arises from a combination of their closed crystal field shells, spherical aromaticity and electrostatic attraction force.
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561Bandyopadhyay, D.; Kaur, P.; Sen, P. New insights into applicability of Electron-counting rules in transition metal encapsulating Ge cage clusters. J. Phys. Chem. A 2010, 114, 12986– 12991, DOI: 10.1021/jp106354d561https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVGktLjL&md5=b97c2aea2e62d8b9b05b774a83886cadNew Insights into Applicability of Electron-Counting Rules in Transition Metal Encapsulating Ge Cage ClustersBandyopadhyay, Debashis; Kaur, Prabhsharan; Sen, PrasenjitJournal of Physical Chemistry A (2010), 114 (50), 12986-12991CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The relative stability of Sc, Ti, and V encapsulating Gen clusters in the size range n = 14-20 has been studied through first-principles electronic structure calcns. based on d. functional theory. Variations of the embedding energy, gap between the highest occupied and the lowest occupied MOs, ionization potential, vertical detachment energy, and electron affinity with cluster size have been calcd. to identify clusters with enhanced stability. The enhanced stability of some clusters can be very well explained as due to the formation of a filled shell free-electron gas inside the Ge cages. For the first time, direct evidence of the formation of a free-electron gas is also presented. In some other clusters, enhanced stability is found to originate from geometric effects. Some clusters that may be expected to have enhanced stability from simple electron counting rules do not show that. These results provide new insights into the long-standing question of whether electron counting rules can explain the relative stability of transition metal encapsulated semiconductor clusters and show that these clusters are too complex for such simple generalizations.
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562Tang, C.; Liu, M.; Zhu, W.; Deng, K. Probing the geometric, optical, and magnetic properties of 3d transition-metal endohedral Ge12M (M = Sc–Ni) clusters. Comput. Theor. Chem. 2011, 969, 56– 60, DOI: 10.1016/j.comptc.2011.05.012562https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXps1aqtbo%253D&md5=e1cf18bb08851145c08cc27d43451f1fProbing the geometric, optical, and magnetic properties of 3d transition-metal endohedral Ge12M (M = Sc-Ni) clustersTang, Chunmei; Liu, Mingyi; Zhu, Weihua; Deng, KaimingComputational & Theoretical Chemistry (2011), 969 (1-3), 56-60CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The geometric, optical, and magnetic properties of the 3d transition-metal endohedral Ge12M (M = Sc-Ni) clusters are studied using the relativistic all-electron d. functional theory. The ground state geometry of the Ge12M cluster is probably pseudoicosahedron. The Eg shows that all Ge12M clusters are perhaps partial metallic. The optical gaps of Ge12M are blueshifted compared to that of Ge122- and can be tuned by doping different transition-metal atom. The magnetic moments of Ge12M vary from 1 to 5μ B, implying they have potential utility in new nanomaterials with tunable magnetic properties.
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563Tai, T. B.; Nguyen, M. T. Enhanced stability by three-dimensional aromaticity of endohedrally doped clusters X10M0/– with X = Ge, Sn, Pb and M = Cu, Ag. J. Phys. Chem. A 2011, 115, 9993– 9999, DOI: 10.1021/jp111324n563https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpvVerurs%253D&md5=7a504f5b89b0f7d84d0de03eebc62d00Enhanced Stability by Three-Dimensional Aromaticity of Endohedrally Doped Clusters X10M0/- with X = Ge, Sn, Pb and M = Cu, Ag, AuTai, Truong Ba; Nguyen, Minh ThoJournal of Physical Chemistry A (2011), 115 (35), 9993-9999CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The group 14 clusters encapsulated by coinage metals in neutral and anionic states X10M0/- (X = Ge, Sn, Pb and M = Cu, Ag, Au) are investigated using quantum chem. calcns. with the DFT/B3LYP functional and coupled-cluster CCSD(T) theory. Addn. of transition metals into the empty cages forms high symmetry endohedral structures, except for Ge10Ag0/-. In agreement with expts. available for X10Cu, the D4d global min. of the anions are calcd. to be magic clusters with large frontier orbital gaps, high vertical and adiabatic detachment energies, and large embedding energies and binding energies as compared to those of the empty cages X102-. The enhanced stability of these magic clusters can be rationalized by the three-dimensional aromaticity.
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564Tai, T. B.; Nguyen, H. M. T.; Nguyen, M. T. The group 14 cationic clusters by encapsulation of coinage metals X10M+, with X = Ge, Sn, Pb and M = Cu, Ag, Au: Enhanced stability of 40 valence electron systems. Chem. Phys. Lett. 2011, 502, 187– 193, DOI: 10.1016/j.cplett.2010.12.021564https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpsVGksw%253D%253D&md5=e9f6704b08c244ac081f4dc1da742d15The group 14 cationic clusters by encapsulation of coinage metals X10M+, with X = Ge, Sn, Pb and M = Cu, Ag, Au: Enhanced stability of 40 valence electron systemsTai, Truong Ba; Nguyen, Hue Minh Thi; Nguyen, Minh ThoChemical Physics Letters (2011), 502 (4-6), 187-193CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The coinage metal encapsulated group 14 cationic clusters X10M+ (X = Ge, Sn, Pb and M = Cu, Ag, Au) are investigated using quantum chem. calcns. While Cu- and Au-doped clusters have similar stability, Ag-doped counterparts are less stable. The D 4d global min. have large frontier orbital gaps and binding energies, and are magic clusters of 40 valence electrons that satisfy the jellium shell model. The concept of doubly spherical aromaticity, based on the no. of 2(N + 1)2 π and σ valence electrons, is proposed to account for the enhanced stability. Predictions are in good agreement with expt. for available X10Cu+ clusters.
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565King, R.; Silaghi-Dumitrescu, I.; Uta, M. Endohedral beryllium atoms in ten-vertex germanium clusters: Effect of a small interstitial atom on the cluster geometry. J. Phys. Chem. A 2011, 115, 2847– 2852, DOI: 10.1021/jp110673s565https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjt1Git7g%253D&md5=8c00a81b9a43f6005dcea5efc974568dEndohedral Beryllium Atoms in Ten-Vertex Germanium Clusters: Effect of a Small Interstitial Atom on the Cluster GeometryKing, R. B.; Silaghi-Dumitrescu, I.; Uta, M. M.Journal of Physical Chemistry A (2011), 115 (13), 2847-2852CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Ten-vertex clusters are unusually versatile because polyhedra with 3-, 4-, and 5-fold symmetry are possible and are found in exptl. known structures. Such clusters therefore provide useful probes for subtle effects on cluster structure such as changing the electron count or introducing an interstitial atom. In this connection, DFT shows that one of the smallest possible interstitial atoms, namely beryllium, has relatively little effect on the structures of Be@Ge10z (z = +2, 0, -2, -4) clusters. Thus the same C3v and D4d polyhedra are found as the lowest energy structures for the isoelectronic pairs Be@Ge102+/Ge10 and Be@Ge10/Ge102-. Even for the more complicated potential energy surfaces of the Be@Ge102-/Ge104- and Be@Ge104-/Ge106- systems, the lowest energy structures are remarkably similar. Thus the same C2v structures are the global min. for both Be@Ge102- and Ge104-. Similarly, the same slipped pentagonal prism structures are the global min. for both Be@Ge104- and Ge106-.
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566Kapila, N.; Jindal, V.; Sharma, H. Structural, electronic and magnetic properties of Mn, Co, Ni in Gen for (n = 1–13). Phys. B 2011, 406, 4612– 4619, DOI: 10.1016/j.physb.2011.09.038566https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlGgu7nF&md5=e26f6763a00d2a054cd962ae8c5a0116Structural, electronic and magnetic properties of Mn, Co, Ni in Gen for (n=1-13)Kapila, Neha; Jindal, V. K.; Sharma, HiteshPhysica B: Condensed Matter (Amsterdam, Netherlands) (2011), 406 (24), 4612-4619CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)The structural, electronic and magnetic properties of TMGen (TM = Mn, Co, Ni; n = 1-13) were studied using spin polarized d. functional theory. The transition metal (TM) atom prefers to occupy surface positions for n<9 and endohedral positions for n ≥ 9. The crit. size of the cluster to form endohedral complexes is at n = 9, 10 and 11 for Mn, Co and Ni, resp. The binding energy of TMGen clusters increases with increase in cluster size. The Ni doped Gen clusters showed higher stability as compared to Mn and Co doped Gen clusters. The HOMO-LUMO gap for spin up and down electronic states of Gen clusters is found to change significantly on TM doping. The magnetic moment in TMGen is introduced due to the presence of TM. The magnetic moment is mainly localized at the TM site and neighboring Ge atoms. The magnetic moment is quenched in NiGen clusters for all n except for n = 2, 4 and 8.
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567Uţă, M.; Cioloboc, D.; King, R. Cobalt-centered ten-vertex germanium clusters: The pentagonal prism as an alternative to polyhedra predicted by the Wade–Mingos rules. Inorg. Chem. 2012, 51, 3498– 3504, DOI: 10.1021/ic202226k567https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjt1SqtL0%253D&md5=56f4bdf02517d05ebaefb8b20a22adf0Cobalt-Centered Ten-Vertex Germanium Clusters: The Pentagonal Prism as an Alternative to Polyhedra Predicted by the Wade-Mingos RulesUta, M. M.; Cioloboc, D.; King, R. B.Inorganic Chemistry (2012), 51 (6), 3498-3504CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)One of the most exciting recent (2009) discoveries in metal cluster chem. is the pentagonal prismatic Co@Ge103- ion, found in [K(2,2,2-crypt)]4[Co@Ge10][Co(1,5-C8H12)2]·toluene and characterized structurally by X-ray diffraction. The complete absence of triangular faces in the pentagonal prismatic structure of Co@Ge103- contradicts expectations from the well-established Wade-Mingos rules, which predict polyhedral structures having mainly or entirely triangular faces. A theor. study on Co@Ge10z systems (z = -5 to +1) predicts a singlet D5h pentagonal prismatic global min. for the trianion Co@Ge103- in accord with this exptl. result. Redox reactions on this pentagonal prismatic Co@Ge103- trianion generate low-energy pentagonal prismatic structures for Co@Ge10z where z = 0, -1, -2, -4, and -5 having quartet, triplet, doublet, doublet, and triplet spin states, resp. Similar theor. methods predict a singlet C3v polyhedral structure for the monoanion Co@Ge10-, similar to previous theor. predictions on the isoelectronic neutral Ni@Ge10 and the structure realized exptl. in the isoelectronic Ni@In1010- found in the K10In10Ni intermetallic. Redox reactions on this C3v polyhedral Co@Ge10- monoanion generate low energy C3v polyhedral structures for Co@Ge10z where z = 0, -2, -3, and -4 having doublet, doublet, triplet, and quartet spin states, resp.
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568Uţă, M.; Cioloboc, D.; Silaghi-Dumitrescu, I.; King, R. The sphericity of the diverse 10-vertex polyhedra found in bare post-transition metal clusters: Germanium clusters with interstitial magnesium atoms as model systems. Theor. Chem. Acc. 2012, 131, 1196, DOI: 10.1007/s00214-012-1196-9There is no corresponding record for this reference.
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569Uţă, M.; King, R. Endohedral beryllium atoms in germanium clusters with eight and fewer vertices: How small can a cluster be and still encapsulate a central atom?. J. Phys. Chem. A 2012, 116, 5227– 5234, DOI: 10.1021/jp302052u569https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xms1yiu74%253D&md5=91d2dba680265a3af8103329aa0a1972Endohedral Beryllium Atoms in Germanium Clusters with Eight and Fewer Vertices: How Small Can a Cluster Be and Still Encapsulate a Central Atom?Uta, M. M.; King, R. B.Journal of Physical Chemistry A (2012), 116 (21), 5227-5234CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Structures of the beryllium-centered germanium clusters Be@Genz (n = 8, 7, 6; z = -4, -2, 0, +2) have been investigated by d. functional theory to provide some insight regarding the smallest metal cluster that can encapsulate an interstitial atom. The lowest energy structures of the eight-vertex Be@Ge8z clusters (z = -4, -2, 0, +2) all have the Be atom at the center of a closed polyhedron, namely, a D4d square antiprism for Be@Ge84-, a D2d bisdisphenoid for Be@Ge82-, an ideal Oh cube for Be@Ge8, and a C2v distorted cube for Be@Ge82+. The Be-centered cubic structures predicted for Be@Ge8 and Be@Ge82+ differ from the previously predicted lowest energy structures for the isoelectronic Ge82- and Ge8. This appears to be related to the larger internal vol. of the cube relative to other closed eight-vertex polyhedra. The lowest energy structures for the smaller seven- and six-vertex clusters Be@Genz (n = 7, 6; z = -4, -2, 0, +2) no longer have the Be atom at the center of a closed Gen polyhedron. Instead, either the Gen polyhedron has opened up to provide a larger vol. for the Be atom or the Be atom has migrated to the surface of the polyhedron. However, higher energy structures are found in which the Be atom is located at the center of a Gen (n = 7, 6) polyhedron. Examples of such structures are a centered C2v capped trigonal prismatic structure for Be@Ge72-, a centered D5h pentagonal bipyramidal structure for Be@Ge7, a centered D3h trigonal prismatic structure for Be@Ge64-, and a centered octahedral structure for Be@Ge6. Cluster buildup reactions of the type Be@Genz + Ge2 → Be@Gen+2z (n = 6, 8; z = -4, -2, 0, +2) are all predicted to be highly exothermic. This suggests that interstitial clusters having an endohedral atom inside a bare post transition element polyhedron with eight or fewer vertices are less than the optimum size. This is consistent with the exptl. observation of several types of 10-vertex polyhedral bare post transition element clusters with interstitial atoms but the failure to observe such clusters with external polyhedra having eight or fewer vertices.
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570Kapila, N.; Garg, I.; Jindal, V.; Sharma, H. First principle investigation into structural growth and magnetic properties in GenCr clusters for n = 1–13. J. Magn. Magn. Mater. 2012, 324, 2885– 2893, DOI: 10.1016/j.jmmm.2012.04.042570https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xntlymtrc%253D&md5=84e9a975589968b36e1f8af04be0035eFirst principle investigation into structural growth and magnetic properties in GenCr clusters for n = 1-13Kapila, Neha; Garg, Isha; Jindal, V. K.; Sharma, HiteshJournal of Magnetism and Magnetic Materials (2012), 324 (18), 2885-2893CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)The ground state structures and their magnetic properties were investigated for GenCr clusters (1 ≤ n ≤ 13) using spin polarized d. functional theory. The growth behavior of GenCr clusters for ≤13 shows preference of Cr atom to stabilize at the exohedral position. The binding energy increases with the increase in cluster size, but shows a small decrease w.r.t. pure Gen clusters. Interestingly, the magnetic moment in Cr doped Gen is found to be either 4 μB or 6 μB and shows no sign of magnetic quenching in any of the ground state structures and isomers investigated up to n = 13. The magnetic moment is mainly localized at the Cr atom along with small induced magnetic moment on surrounding Ge atoms. The results are consistent with the available theor. results for ≤5.
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571Hung, Y.-M.; Ho, G.-M.; Zhang, Z.-F. Bonding properties and isomeric conversion pathways from exohedral to endohedral BeGe8 clusters. Comput. Theor. Chem. 2012, 999, 154– 161, DOI: 10.1016/j.comptc.2012.08.029571https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1Gqs7rM&md5=ee0106c06ae813b39a16f6b18904e073Bonding properties and isomeric conversion pathways from exohedral to endohedral BeGe8 clustersHung, Yu-Ming; Ho, Gong-Ming; Zhang, Zhen-FengComputational & Theoretical Chemistry (2012), 999 (), 154-161CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The B3LYP/6-31G* method was employed to optimize the BeGe8 isomeric structures. Some adsorptive precursors can be formed without experiencing activation energy. Hirshfeld charges and Mayer total valences anal. show that a larger extent of back-donation leading to a higher Be negativity and hypervalency. All Be-Ge bonds are covalent, not ionic, according to charge partitions and M.O. anal. Cluster energies obtained by the 6-31G* and 6-311++G(3df) basis sets show significant difference and the 6-311++G(3df) energies correlate better with bonding properties. The 6-31G* ground state is a cubic Be@Ge8 that agrees with the literature. However, the 6-311++G(3df) ground state is a cube-distorted C2v Be@Ge8 with less cage strain. The Wade-Mingos rule was added to explain this change. Conversion pathways from the lowest-energetic adsorptive exohedrons to the lowest-energetic endohedrons have been explored and the Mayer bond orders assisted to describe part of the conversion progress.
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572Kumar, M.; Bhattacharyya, N.; Bandyopadhyay, D. Architecture, electronic structure and stability of TM@Gen (TM = Ti, Zr and Hf; n = 1-20) clusters: A density functional modeling. J. Mol. Model. 2012, 18, 405– 418, DOI: 10.1007/s00894-011-1122-4572https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XksVamtg%253D%253D&md5=0aa0d7ae61146a3f7556e41333d2a05cArchitecture, electronic structure and stability of TM@Ge(n) (TM = Ti, Zr and Hf; n = 1-20) clusters: a density functional modelingKumar, Manish; Bhattacharyya, Nilanjana; Bandyopadhyay, DebashisJournal of Molecular Modeling (2012), 18 (1), 405-418CODEN: JMMOFK; ISSN:0948-5023. (Springer)The present study reports the geometry, electronic structure and properties of neutral and anionic transition metal (TM = Ti, Zr and Hf) doped germanium clusters contg. 1 to 20 germanium atoms within the framework of LCAO d. functional theory under spin polarized generalized gradient approxn. Different parameters, like, binding energy (BE), embedding energy (EE), energy gap between the highest occupied and lowest unoccupied MOs (HOMO-LUMO), ionization energy (IP), electron affinity (EA), chem. potential etc. of the energetically stable clusters (ground state cluster) in each size are calcd. From the variation of these parameters with the size of the clusters the most stable cluster within the range of calcn. is identified. It is found that the clusters having 20 valence electrons turn out to be relatively more stable in both the neutral and the anionic series. The sharp drop in IP as the valence electron count increases from 20 to 21 in neutral cluster is in agreement with predictions of shell models. To study the vibrational nature of the clusters, IR and Raman spectrum of some selected TM@Gen (n = 15,16,17) clusters are also calcd. and compared. In the end, relevance of calcd. results to the design of Ge-based super-atoms is discussed.
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573Bandyopadhyay, D. Architectures, electronic structures, and stabilities of Cu-doped Gen clusters: Density functional modeling. J. Mol. Model. 2012, 18, 3887– 3902, DOI: 10.1007/s00894-012-1374-7573https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFSltrjO&md5=8911c47fc5710822b78f5458544848f2Architectures, electronic structures, and stabilities of Cu-doped Gen clusters: density functional modelingBandyopadhyay, DebashisJournal of Molecular Modeling (2012), 18 (8), 3887-3902CODEN: JMMOFK; ISSN:0948-5023. (Springer)The present study reports the geometries, electronic structures, growth behavior, and stabilities of neutral and ionized copper-doped germanium clusters contg. 1-20 Ge atoms within the framework of LCAO d. functional theory (DFT) under the spin-polarized generalized gradient approxn. It was found that Cu-capped Gen (or Cu-substituted Gen+1) and Cu-encapsulated Ge n clusters mostly occur in the ground state at a particular cluster size (n). In order to explain the relative stabilities of the ground-state clusters, parameters such as the av. binding energy per atom (BE), the embedding energy (EE), and the fragmentation energy (FE) of the clusters were calcd., and the resulting values are discussed. To explain the chem. stabilities of the clusters, parameters such as the energy gap between the highest occupied and the lowest unoccupied MOs (the HOMO-LUMO gap), the ionization energy (IP), the electron affinity (EA), the chem. potential (μ), the chem. hardness (η), and the polarizability were calcd., and the resulting values are also discussed. Natural AO (NAO) and natural bond orbital (NBO) analyses were also used to det. the electron-counting rule that should be applied to the most stable Ge10Cu cluster. Finally, the relevance of the calcd. results to the design of Ge-based superatoms is discussed.
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574Dhaka, K.; Trivedi, R.; Bandyopadhyay, D. Electronic structure and stabilities of Ni-doped germanium nanoclusters: A density functional modeling study. J. Mol. Model. 2013, 19, 1473– 1488, DOI: 10.1007/s00894-012-1690-y574https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXksF2mtrs%253D&md5=c8d0589e0b02c8215509b777b57104e1Electronic structure and stabilities of Ni-doped germanium nanoclusters: a density functional modeling studyDhaka, Kapil; Trivedi, Ravi; Bandyopadhyay, DebashisJournal of Molecular Modeling (2013), 19 (4), 1473-1488CODEN: JMMOFK; ISSN:0948-5023. (Springer)The present study reports the geometry, electronic structure, growth behavior and stability of neutral and ionized nickel encapsulated germanium clusters contg. 1-20 germanium atoms within the framework of a linear combination of AO d. functional theory (DFT) under a spin polarized generalized gradient approxn. In the growth pattern, Ni-capped Gen and Ni-encapsulated Gen clusters appear mostly as theor. ground state at a particular size. To explain the relative stability of the ground state clusters, variation of different parameters, such as av. binding energy per atom (BE), embedding energy (EE) and fragmentation energy (FE) of the clusters, were studied together with the size of the cluster. To explain the chem. stability of the clusters, different parameters, e.g., energy gap between the highest occupied and lowest unoccupied MOs (HOMO-LUMO gap), ionization energy (IP), electron affinity (EA), chem. potential (μ), chem. hardness (η), and polarizability etc. were calcd. and are discussed. Finally, natural bond orbital (NBO) anal. was applied to understand the electron counting rule applied in the most stable Ge10Ni cluster. The importance of the calcd. results in the design of Ge-based superatoms is discussed.
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575Li, X.; Su, K.; Yang, X.; Song, L.; Yang, L. Size-selective effects in the geometry and electronic property of bimetallic Au–Ge nanoclusters. Comput. Theor. Chem. 2013, 1010, 32– 37, DOI: 10.1016/j.comptc.2013.01.012575https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXktlCqsbg%253D&md5=e434dbcff05eb3c11e5ba66901085f18Size-selective effects in the geometry and electronic property of bimetallic Au-Ge nanoclustersLi, Xiaojun; Su, Kehe; Yang, Xiaohui; Song, Limei; Yang, LimingComputational & Theoretical Chemistry (2013), 1010 (), 32-37CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)We systematically investigated the size-selective effects of geometrical structures and electronic properties on anionic AuGe-n (n = 1-13) nanoclusters by using d. functional theory (DFT-B3LYP) calcns. with double-ξ LanL2DZ basis set. The lowest-energy structures and their low-lying isomers were identified. Compared with the neutral clusters, the ground state structures of AuGe-8 and AuGe-9 were obviously rearranged due to the addn. of an extra electron. The threshold no. of endohedral cage-like AuGe-n clusters was favored at n = 10, whereas the most stable cluster was found at n = 12, and reflected by the av. binding energies and second-order difference in the total energies. The present results demonstrated that the induced effects by an addnl. electron to the neutral clusters can enhance their stabilities. However, the values of HOMO-LUMO gaps have a decreasing tendency along with the increasing no. of Ge atoms. Adiabatic electron affinity (AEA), vertical electron affinity (VEA), and vertical detachment energy (VDE) were obtained and discussed in detail. The chem. bondings of some stable nanoclusters were also analyzed with the electron localization function (ELF).
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576Trivedi, R.; Dhaka, K.; Bandyopadhyay, D. Study of electronic properties, stabilities and magnetic quenching of molybdenum-doped germanium clusters: A density functional investigation. RSC Adv. 2014, 4, 64825– 64834, DOI: 10.1039/C4RA11825A576https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVGktbvP&md5=68b33bead7e4a0f5328d59e052bbfff3Study of electronic properties, stabilities and magnetic quenching of molybdenum-doped germanium clusters: a density functional investigationTrivedi, Ravi; Dhaka, Kapil; Bandyopadhyay, DebashisRSC Advances (2014), 4 (110), 64825-64834CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Evolution of electronic structures, properties and stabilities of neutral and cationic molybdenum encapsulated germanium clusters (Mo@Gen, n = 1 to 20) has been investigated using the linear combination of AO d. functional theory method with effective core potential. From the variation of different thermodn. and chem. parameters of the ground state clusters during the growth process, the stability and electronic structures of the clusters is explained. From the study of the distance-dependent nucleus-independent chem. shifts (NICS), we found that Mo@Ge12 with hexagonal prism-like structure is the most stable isomer and possesses strong arom. character. D. of states (DOS) plots of different clusters is then discussed to explain the role of d-orbitals of the Mo atom in hybridization. Quenching of the magnetic moment of the Mo atom with increase in the size of the cluster is also discussed. Finally, the validity of the 18-electron counting rule is applied to further explain the stability of the metallo-inorg. magic cluster Mo@Ge12 and the possibility of Mo-based cluster-assembled materials is discussed.
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577Borshch, N.; Pereslavtseva, N.; Kurganskii, S. Spatial and electronic structures of the germanium-tantalum clusters TaGen– (n = 8–17). Phys. Solid State 2014, 56, 2336– 2342, DOI: 10.1134/S1063783414110055577https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVyksrrE&md5=22c56d98b94e7d410d8b471f3ac8005bSpatial and electronic structures of the germanium-tantalum clusters TaGe-n (n = 8-17)Borshch, N. A.; Pereslavtseva, N. S.; Kurganskii, S. I.Physics of the Solid State (2014), 56 (11), 2336-2342CODEN: PSOSED; ISSN:1063-7834. (SP MAIK Nauka/Interperiodica)The results of optimizing the spatial structure and calcd. electronic spectra of the TaGe-n anion clusters (n = 8-17) have been presented. The calcns. have been performed in terms of the d. functional theory. The most probable spatial structures of clusters detected in the expt. have been detd. by comparing the calcd. and available exptl. data.
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578Borshch, N.; Pereslavtseva, N.; Kurganskii, S. Spatial structure and electron energy spectra of ScGen– (n = 6–16) clusters. Russ. J. Phys. Chem. B 2015, 9, 9– 18, DOI: 10.1134/S1990793115010030578https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXotVSkt7k%253D&md5=41bdf6a8957db1343107a412d9209c23Spatial structure and electron energy spectra of ScGe-n (n = 6-16) clustersBorshch, N. A.; Pereslavtseva, N. S.; Kurganskii, S. I.Russian Journal of Physical Chemistry B (2015), 9 (1), 9-18CODEN: RJPCCT; ISSN:1990-7923. (SP MAIK Nauka/Interperiodica)The results of optimization of the spatial structure and the calcd. electronic spectra of anionic ScGe-n (n = 6-16) clusters are presented. Calcns. were carried out in the framework of d. functional theory. By comparing the calcn. results and available exptl. data, the three-dimensional structures of the clusters detected in the expt. are detd.
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579Dhaka, K.; Bandyopadhyay, D. Study of the electronic structure, stability and magnetic quenching of CrGen (n= 1–17) clusters: A density functional investigation. RSC Adv. 2015, 5, 83004– 83012, DOI: 10.1039/C5RA13849C579https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsFShtrzP&md5=b0ab63238d337c4e7045bc52ebef6720Study of the electronic structure, stability and magnetic quenching of CrGen (n = 1-17) clusters: a density functional investigationDhaka, Kapil; Bandyopadhyay, DebashisRSC Advances (2015), 5 (101), 83004-83012CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)In the present report the evolution of the electronic structure, stability and magnetic quenching of CrGen nanoclusters has been carried out using d. functional theory (DFT). From the nature of the variation of the different thermodn. and chem. parameters, the CrGe10 and CrGe14 ground state clusters are identified as the most stable species. It is obsd. that the enhanced stability of CrGe10 and CrGe14 are due to the closed shell filled structure of the Cr-AOs and follow the 18-electron counting rule. It is found that the strong mixing of the Cr d-orbital with the s- and p-AOs of the Ge atoms in the cluster are mainly responsible for the stability and quenching of the Cr magnetic moment in the clusters. Calcd. CPs also give addnl. information about the bonding and its effect on the stability of the clusters. Calcd. IR and Raman spectra also support these results.
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580Borshch, N.; Kurganskii, S. Spatial structure and electron energy spectrum of HfGen– (n = 6–20) clusters. Inorg. Mater. 2015, 51, 870– 876, DOI: 10.1134/S0020168515080075580https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVChsbbJ&md5=04b9530b922e947413005f96c37288a2Spatial structure and electron energy spectrum of HfGe-n (n = 6-20) clustersBorshch, N. A.; Kurganskii, S. I.Inorganic Materials (2015), 51 (9), 870-876CODEN: INOMAF; ISSN:0020-1685. (SP MAIK Nauka/Interperiodica)This paper presents spatial structure optimization results and calcd. electronic spectra for HfGe-n (n = 6-20) anion clusters. Comparison of the calcn. results and available exptl. data makes it possible to identify the most likely spatial structures of clusters detected in expts. Cage structures of the clusters, with an encapsulated hafnium atom, are stable for n ≥ 12. The clusters with n ≥ 12, 14, 15, and 18 are "magic" in the series of germanium-hafnium anion clusters.
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581Uţă, M.; King, R. Manganese-centered ten-vertex germanium clusters: The strong field Ge10 ligand encapsulating a transition metal. J. Coord. Chem. 2015, 68, 3485– 3497, DOI: 10.1080/00958972.2015.1073267581https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlGnsrnL&md5=24dc86ef3fd773ca35e30e6a7513c418Manganese-centered ten-vertex germanium clusters: the strong field Ge10 ligand encapsulating a transition metalUta, M. M.; King, R. B.Journal of Coordination Chemistry (2015), 68 (19), 3485-3497CODEN: JCCMBQ; ISSN:0095-8972. (Taylor & Francis Ltd.)The exptl. realization of pentagonal prismatic structures for M@Ge103- (M = Co, Fe) contg. interstitial transition metal atoms makes of interest the chem. of corresponding manganese derivs. Mn@Ge10z. The neutral Mn@Ge10 may be regarded as a complex of a polyhedral ligand with an interstitial Mn in the +2 oxidn. state. However, the lowest energy Mn@Ge10 structure with the expected sextet spin state for high-spin d5 Mn(II) lies ∼23 kcal mol-1 in energy above the lowest energy isomer thereby suggesting that such germanium polyhedra function as strong field ligands for encapsulated transition metals. The lowest energy structures for the Mn@Ge10z anions (z = -1 to -5) are all centered pentagonal prisms. Higher energy Mn@Ge10z structures have outer Ge10 polyhedra based on the tetracapped trigonal prism similar to the lowest energy Co@Ge10- structure and on the bicapped square antiprism similar to the B10H102- deltahedron. Other Mn@Ge10z structures have outer Ge10 polyhedra with four or five quadrilateral faces as well as six or eight triangular faces, resp. Bioctahedral (Ge5)2Mn5- structures were also found for the pentaanion with a manganese vertex common to two MnGe5 octahedra. The cationic species Mn@Ge10+ was found to have a more complicated potential surface than the anions. Tetracapped trigonal prismatic and bicapped square antiprismatic structures as well as a variety of more open structures were found for Mn@.
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582Qin, W.; Lu, W.-C.; Xia, L.-H.; Zhao, L.-Z.; Zang, Q.-J.; Wang, C.; Ho, K. Structures and stability of metal-doped GenM (n = 9, 10) clusters. AIP Adv. 2015, 5, 067159, DOI: 10.1063/1.4923316582https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFCqsrjF&md5=dab35cb77a704baf154eda9d01b33e88Structures and stability of metal-doped GenM (n = 9, 10) clustersQin, Wei; Lu, Wen-Cai; Xia, Lin-Hua; Zhao, Li-Zhen; Zang, Qing-Jun; Wang, C. Z.; Ho, K. M.AIP Advances (2015), 5 (6), 067159/1-067159/9CODEN: AAIDBI; ISSN:2158-3226. (American Institute of Physics)The lowest-energy structures of neutral and cationic GenM (n = 9, 10; M = Si, Li, Mg, Al, Fe, Mn, Pb, Au, Ag, Yb, Pm and Dy) clusters were studied by genetic algorithm (GA) and first-principles calcns. The calcn. results show that doping of the metal atoms and Si into Ge9 and Ge10 clusters is energetically favorable. Most of the metal-doped Ge cluster structures can be viewed as adding or substituting metal atom on the surface of the corresponding ground-state Gen clusters. However, the neutral and cationic FeGe9,10,MnGe9,10 and Ge10Al are cage-like with the metal atom encapsulated inside. Such cage-like transition metal doped Gen clusters are shown to have higher adsorption energy and thermal stability. Our calcn. results suggest that Ge9,10Fe and Ge9Si would be used as building blocks in cluster-assembled nanomaterials because of their high stabilities. (c) 2015 American Institute of Physics.
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583Jaiswal, S.; Kumar, V. Growth behavior and electronic structure of neutral and anion ZrGen (n = 1–21) clusters. Comput. Theor. Chem. 2016, 1075, 87– 97, DOI: 10.1016/j.comptc.2015.11.013583https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFGnu7nF&md5=bcb052474b01b5a9756b11c804313ba1Growth behavior and electronic structure of neutral and anion ZrGen (n = 1-21) clustersJaiswal, S.; Kumar, VijayComputational & Theoretical Chemistry (2016), 1075 (), 87-97CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)A review. The at. and electronic structure of both neutral and neg. charged ZrGen (n = 1-21) clusters have been studied using ab initio calcns. The at. structures have been identified by comparing the calcd. results of the electronic spectra of the anion clusters with the available photoelectron spectroscopy data. We find that the at. structure of ZrGen cluster can be derived by adding one or more Ge atoms on smaller clusters. Our results show that in some cases a higher energy isomer of ZrGen anion cluster may be present in expts., but the neutral of such an anion is often the lowest energy isomer. This shows the importance of the lowest energy isomer of neutral clusters in expt. In some cases, it is found that two different isomers of the anion of a cluster converge to the identical isomer of the neutral. A large value of the HOMO-LUMO gap as well as binding energy per atom has been calcd. for ZrGe16 neutral cluster and hence, it is more stable and less reactive as compared to other clusters. This agrees with the high abundance of ZrGe16 cluster in expts. The Zr atom is encapsulated in a cage-like structure at a size of thirteen or more Ge atoms. This also agrees with the expts. Further, we have calcd. vertical and adiabatic detachment energies and obtained a low value for ZrGe16 also in agreement with expts. The addn. of an electron to a neutral ZrGe11 cluster, however, changes its at. structure drastically and thus, the calcd. adiabatic and vertical detachment energies for ZrGe11 anion differ very significantly.
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584Siouani, C.; Mahtout, S.; Safer, S.; Rabilloud, F. Structure, stability, and electronic and magnetic properties of VGen (n = 1–19) clusters. J. Phys. Chem. A 2017, 121, 3540– 3554, DOI: 10.1021/acs.jpca.7b00881584https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXmtFCgtbg%253D&md5=ca5ba13090f92490119d5edbac2b2caaStructure, Stability, and Electronic and Magnetic Properties of VGen (n = 1-19) ClustersSiouani, C.; Mahtout, S.; Safer, S.; Rabilloud, F.Journal of Physical Chemistry A (2017), 121 (18), 3540-3554CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We systematically study the equil. geometries and electronic and magnetic properties of Gen+1 and VGen (n = 1-19) clusters using the d. functional theory approach within the generalized gradient approxn. Endohedral structures in which the vanadium atom is encapsulated inside a Gen cage are predicted to be favored for n ≥ 10. The dopant V atom in the Gen clusters has not an immediate effect on the stability of small germanium clusters (n < 6), but it largely contributes to strengthen the stability for n ≥ 7. Our study enhances the large stability of the VGe14 cluster, which presents an Oh symmetry cagelike geometry and a peculiar electronic structure in which the valence electrons of V and Ge atoms are delocalized and exhibit a shell structure assocd. with the quasi-spherical geometry. Consequently, this cluster is proposed to be a good candidate to be used as the building blocks for developing new materials. The cluster size dependence of the stability, the vertical ionization potentials, and electron affinities of Gen+1 and VGen are presented. Magnetic properties and the partial d. of states of the most stable VGen clusters are also discussed.
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585Borshch, N.; Kurganskii, S. Anionic germanium–niobium clusters: atomic structure, mechanisms of cluster formation, and electronic spectra. Russ. J. Phys. Chem. A 2018, 92, 1720– 1726, DOI: 10.1134/S0036024418090078585https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhs1Kgu7fE&md5=4152dc6ff919bf10b4f0f0b39483fac4Anionic Germanium-Niobium Clusters: Atomic Structure, Mechanisms of Cluster Formation, and Electronic SpectraBorshch, N. A.; Kurganskii, S. I.Russian Journal of Physical Chemistry A (2018), 92 (9), 1720-1726CODEN: RJPCBS; ISSN:0036-0244. (Pleiades Publishing, Ltd.)Abstr.: Results from optimizing the at. structure of anionic clusters NbGe-n (n = 8-20) are presented, along with their calcd. electronic spectra. The calcns. are performed within the d. functional theory. The real spatial structures of the clusters are detd. by comparing the calcd. and known exptl. data.
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586Borshch, N.; Kurganskii, S. Atomic structure and electronic properties of anionic germanium–zirconium clusters. Inorg. Mater. 2018, 54, 1– 7, DOI: 10.1134/S0020168518010028586https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjslOqs7w%253D&md5=f8d1f7dcbc2468deb8613bf4fd0dc8d2Atomic Structure and Electronic Properties of Anionic Germanium-Zirconium ClustersBorshch, N. A.; Kurganskii, S. I.Inorganic Materials (2018), 54 (1), 1-7CODEN: INOMAF; ISSN:0020-1685. (Pleiades Publishing, Ltd.)A review. This paper presents spatial structure optimization results and calcd. electronic spectra for ZrGe-n (n = 8-20) anion clusters. Comparison of d.-functional calcn. results and available exptl. data allows us to identify real spatial structures of the clusters. The formation of stable endohedral ZrGe-n clusters is possible for n ≥ 12. The clusters with a smaller no. of germanium atoms predominantly have exohedral structures.
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587Mahtout, S.; Siouani, C.; Rabilloud, F. Growth behavior and electronic structure of noble metal-doped germanium clusters. J. Phys. Chem. A 2018, 122, 662– 677, DOI: 10.1021/acs.jpca.7b09887587https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVSntbjJ&md5=2c9646a512f3a5861fb8721e20bf95ebGrowth Behavior and Electronic Structure of Noble Metal-Doped Germanium ClustersMahtout, Sofiane; Siouani, Chaouki; Rabilloud, FranckJournal of Physical Chemistry A (2018), 122 (2), 662-677CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Structures, energetics and electronic properties of noble metal-doped germanium (MGen with M = Cu, Ag, Au; n = 1-19) clusters are systematically investigated by using the d.-functional theory (DFT) approach. The endohedral structures in which the metal atom is encapsulated inside a germanium cage appear at n = 10 when the dopant is Cu, and n = 12 for M = Ag and Au. While Cu doping enhances the stability of the corresponding germanium frame, the binding energies of AgGen and AuGen are always lower than those of pure germanium clusters. Our results highlight the great stability of the CuGe10 cluster in a D4d structure, and to a lesser extent that of AgGe15 and AuGe15 which exhibits a hollow cage-like geometry. The sphere-type geometries obtained for n = 10-15 present a peculiar electronic structure in which the valence electrons of the noble metal and Ge atoms are delocalized and exhibit a shell structure assocd. with the quasi-spherical geometry. It is found that the coinage metal is able to give both s- and d-type electrons to be reorganized together with the valence electrons of Ge atoms through a pooling of electrons. The cluster size dependence of the stability, the frontier orbital energy gap, the vertical ionization potentials, and electron affinities are given.
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588Triedi, R. K.; Bandyopadhyay, D. Insights of the role of shell closing model and NICS in the stability of NbGen (n = 7–18) clusters: A first-principles investigation. J. Mater. Sci. 2019, 54, 515– 528, DOI: 10.1007/s10853-018-2858-3588https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhs1CmurzN&md5=98c38a1044b50cdd8601f19a6df476bcInsights of the role of shell closing model and NICS in the stability of NbGen (n = 7-18) clusters: a first-principles investigationTriedi, Ravi Kumar; Bandyopadhyay, DebashisJournal of Materials Science (2019), 54 (1), 515-528CODEN: JMTSAS; ISSN:0022-2461. (Springer)The structures, energetics and electronic properties of neutral and cationic Nb-doped Gen (n = 7-18) clusters are systematically investigated using DFT-B3LYP method. The isomers in which the Nb atom is encapsulated inside a germanium cage are relatively stable compared to the exohedral surface doping. The thermodn. stability and chem. activity of the ground-state isomers are analyzed through various energetic parameters. The results highlight the enhanced stability of the neutral NbGe12 hexagonal prism-like structure with D6h symmetry and cationic NbGe16 fullerene isomers. The neg. nucleus-independent chem. shift can explain the enhanced stability of neutral NbGe12. However, the enhanced stability of cationic NbGe16 is explained by shell closing model assocd. with the quasi-spherical geometry with a sequence 1S21P61D101F61G122S22P6IF8IG62D10 following Hund's rule. To understand the effect of hybridization on stability, we have calcd. d. of states (DOS) and projected DOS (PDOS). From PDOS, it is clear that Nb-p and Ge-s and p orbitals are mainly take part in hybridization; however, near below Fermi level, the dominating contribution comes from Nb-d orbitals. In addn., IR and Raman spectra of clusters are also calcd. to explain their vibrational properties of the isomers. Specifically, IR spectrum of the clusters in the range of 12-16 shows the possible application of these clusters in the IR sensing device.
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589Jin, Y.; Tian, Y.; Kuang, X.; Lu, C.; Cabellos, J. L.; Mondal, S.; Merino, G. Structural and electronic properties of ruthenium-doped germanium clusters. J. Phys. Chem. C 2016, 120, 8399– 8404, DOI: 10.1021/acs.jpcc.6b02225589https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltlOmt7o%253D&md5=7f4b5b0a922deb8109742a72460a13eaStructural and Electronic Properties of Ruthenium-Doped Germanium ClustersJin, Yuanyuan; Tian, Yonghong; Kuang, Xiaoyu; Lu, Cheng; Cabellos, Jose Luis; Mondal, Sukanta; Merino, GabrielJournal of Physical Chemistry C (2016), 120 (15), 8399-8404CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We have performed a global min. search for the multicharged ruthenium-doped germanium clusters with the formula RuGenq (n = 2-12, q = -2, - 3) using a particle swarm optimization metaheuristic coupled with d. functional theory computations. Leading candidates for the lowest energy forms have been identified. Among the global min. geometries, going from the size of n = 2 to n = 12, it is perceived that the cluster growth is directed toward the formation of an endohedral aggregate. Particularly, the half-encapsulated structures of RuGe7q and RuGe8q made the bridge between small open-shell (n = 2-6) geometries and the endohedral (n = 9-12) geometries. The endohedral constructions contain the Ru atoms at their interstitial positions. Particularly, the 10-vertex endohedral cluster RuGe102- has an unprecedented 3-connected C3v polyhedral geometry. The pos. values of HOMO energies of global min. anions depict the electronic instability. The countercation effect is discussed to show the compensation of Coulomb repulsion among excess neg. charges. RuGe122- and RuGe123- have S4- and D2d-sym. endohedral shapes, resp., which match with the previous exptl. results. The natural population anal. charge is also examd. to understand the assocd. charge transfers.
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590Tan, Z.; Zhou, T.; Yang, Y. The role of TM’s (M’s) d valence electrons in TM@X12 and M@X12 clusters. AIP Adv. 2016, 6, 125123, DOI: 10.1063/1.4973636590https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXksleitQ%253D%253D&md5=e184120008f84f3c2c745c0572fe13ffThe role of TM's (M's) d valence electrons in TM@X12 and M@X12 clustersTan, Zhiyun; Zhou, Tingwei; Yang, YouchangAIP Advances (2016), 6 (12), 125123/1-125123/9CODEN: AAIDBI; ISSN:2158-3226. (American Institute of Physics)Using the d. functional theory method, the icosahedral TM@X12 (M@X12) clusters (TM=Mn, Tc, Re; M=Zn, Cd, Hg; and X=Sn, Ge), which are composed of Sn12 (Ge12) shell covering a single TM (M) atom, have been systematically examd. to explore the role of TM's (M's) d valence electrons playing in the clusters. The results show that the magnetism originate from the contribution of TM's d valence electrons to TM@X12 clusters, where TM's (M's) d valence electrons are not included in the superat. electronic states to TM@X12 (M@X12) clusters. Taking into account the structural stability (imaginary frequency, binding energy, embedding energy, and core-shell interaction) as well as the chem. stability (HOMO-LUMO gap) after, we proposed that TM@X12 and M@X12 clusters can be assigned as the protyle superatoms. Furthermore, the results suggest that M@C60 clusters can not be superatoms, because their neg. embedding energies and the distance from the center atom (M) to C atom is larger than the sum of their Van Waals radii. Interestingly enough, we may obtain a simple judging method: for a magnetic superatom, the smaller the energy gap between the highest occupied magnetic state (HOMS) and Fermi level or HOMO (MOgap, or MFgap), the easier on the change of its spin magnetic moment. (c) 2016 American Institute of Physics.
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591Middaugh, R.; Muetterties, E. Boron Hydride Chemistry; Academic Press: New York, NY, 1975.There is no corresponding record for this reference.
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592Liu, C.; Li, L. J.; Popov, I. A.; Wilson, R. J.; Xu, C. Q.; Li, J.; Boldyrev, A. I.; Sun, Z. M. Symmetry reduction upon size mismatch: The non-Icosahedral intermetalloid cluster [Co@Ge12]3–. Chin. J. Chem. 2018, 36, 1165– 1168, DOI: 10.1002/cjoc.201800434592https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhvVKqu7nN&md5=a78066c0602cd758ca62be47dd991a9cSymmetry Reduction upon Size Mismatch: The Non-Icosahedral Intermetalloid Cluster [Co@Ge12]3-Liu, Chao; Li, Lei-Jiao; Popov, Ivan A.; Wilson, Robert J.; Xu, Cong-Qiao; Li, Jun; Boldyrev, Alexander I.; Sun, Zhong-MingChinese Journal of Chemistry (2018), 36 (12), 1165-1168CODEN: CJOCEV; ISSN:1001-604X. (Wiley-VCH Verlag GmbH & Co. KGaA)A new complex comprising [Co@Ge12]3- cluster core was synthesized through the reaction of CoMe(PMe3)4 and K4Ge9 in ethylenediamine soln. The pseudo-D5d geometry of this cluster can be viewed as structurally derived from an icosahedral cage via Jahn-Teller effect, leading to notable bonding differences from Ih-[M@E12]q- clusters (E = Sn, Pb with q = 2, 3). The [Co@Ge12]3- cluster represents a structural conundrum. On the basis of the geometric considerations it could be viewed as a sandwich complex. However, chem. bonding anal. revealed that there is a direct covalent multicenter bonding between the two pentagons, thus indicating that the structure should be viewed as an elongated icosahedron. Further theor. calcns. on [M@Ge12]3- (M = Rh, Ir, Mt) indicate that similar compds. of larger-size metal atoms can drive the complete transformation of [M@Ge12]3- clusters from icosahedron structure to a sandwich one.
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593Zhou, S.; Yang, X.; Shen, Y.; King, R. B.; Zhao, J. Dual transition metal doped germanium clusters for catalysis of CO oxidation. J. Alloys Compd. 2019, 806, 698– 704, DOI: 10.1016/j.jallcom.2019.07.297593https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsVylsL%252FL&md5=2ef8c76095b475693be5afd0f0e26a7aDual transition metal doped germanium clusters for catalysis of CO oxidationZhou, Si; Yang, Xiaowei; Shen, Yuebo; King, R. Bruce; Zhao, JijunJournal of Alloys and Compounds (2019), 806 (), 698-704CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)CO oxidn. is a crucial reaction to combat environmental pollution caused by fossil fuel burning, industrial exhaust and vehicle emissions. Searching for efficient catalysts made of economical and earth-abundant elements is vital and remains challenging. Here, the authors show for the first time that dual transition metal doped germanium clusters M2Ge12 (M = Cr, Mn, Fe, Co and Ni), which are exptl. accessible, are promising catalysts for low-temp. CO oxidn. Their first-principles calcns. demonstrate that the reaction barrier has a linear relation with the O2 binding strength on the cluster, with the Ni2Ge12 cluster possessing the lowest barrier of 0.35 eV under the Eley-Rideal mechanism. The binding capability and activity are correlated to the d orbital center of two metal dopants in the cluster. Moreover, these M2Ge12 alloy clusters remain stable during the entire reaction process and exhibit satisfactory thermal stability and resistance to segregation. These theor. results not only extend the application area of germanium-based alloy clusters, but also provide useful guidelines for designing inexpensive catalysts for CO oxidn. and tuning their performance by electronic structure engineering.
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594Meloni, G.; Schmude, R., Jr; Kingcade, J., Jr; Gingerich, K. A. Thermodynamic stability of Sn4, Sn5, Sn6, and Sn7 clusters by Knudsen cell mass spectrometry. J. Chem. Phys. 2000, 113, 1852– 1856, DOI: 10.1063/1.481988594https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXltVWis74%253D&md5=8c7a906ad99b2a03cb7c535a973de2f4Thermodynamic stability of Sn4, Sn5, Sn6, and Sn7 clusters by Knudsen cell mass spectrometryMeloni, G.; Schmude, R. W., Jr.; Kingcade, J. E., Jr.; Gingerich, K. A.Journal of Chemical Physics (2000), 113 (5), 1852-1856CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The Knudsen cell mass spectrometric method has been employed to measure the partial pressures of Snn (n = 1-7) under equil. conditions above liq. tin or a tin-gold alloy, contained in a graphite Knudsen cell. From the all-gas analyzed equil. the following atomization enthalpies ΔaH0 (Snn), and enthalpies of formation, ΔfH298.15 (Snn), in kJ mol-1, have been obtained: Sn4, 750.2±14 and 450.6±14; Sn5, 990.2±22 and 512.3±22; Sn6, 1349.7±28 and 452.8±28; Sn7, 1644.2±37 and 460.0±37. The atomization energies are compared with available theor. values.
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595Schäfer, S.; Assadollahzadeh, B.; Mehring, M.; Schwerdtfeger, P.; Schäfer, R. Structure and electric properties of SnN clusters (N = 6–20) from combined electric deflection experiments and quantum theoretical studies. J. Phys. Chem. A 2008, 112, 12312– 12319, DOI: 10.1021/jp8030754595https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlGhs73E&md5=5160a34acb673277bc9974dfdf17ce9fStructure and Electric Properties of SnN Clusters (N = 6-20) from Combined Electric Deflection Experiments and Quantum Theoretical StudiesSchafer, Sascha; Assadollahzadeh, Behnam; Mehring, Max; Schwerdtfeger, Peter; Schafer, RolfJournal of Physical Chemistry A (2008), 112 (48), 12312-12319CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Elec. deflection expts. were performed on neutral SnN clusters (N = 6-20) at different nozzle temps. in combination with a systematic search for the global min. structures and the calcn. of the dielec. properties based on d. functional theory (DFT-B3P86). For smaller tin clusters (N = 6-11), a good agreement between theory and expt. was found. Taking theor. predicted moments of inertia and the body fixed dipole moment into account permits a quant. simulation of the deflected mol. beam profiles. For larger SnN clusters (N = 12-20), distinct differences between theory and expt. are obsd.; i.e., the predicted dipole moments from the quantum chem. calcns. are significantly larger than the exptl. values. The investigation of the elec. susceptibilities at different nozzle temps. indicates that this is due to the dynamical nature of the tin clusters, which increases with cluster size. As a result, even at the smallest nozzle temp. of 40 K, the dipole moments of Sn12-20 are partially quenched. This clearly demonstrates the limits of current elec. deflection expts. for structural detn. and demonstrates the need for stronger cooling of the clusters in future expts.
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596Oger, E.; Kelting, R.; Weis, P.; Lechtken, A.; Schooss, D.; Crawford, N. R.; Ahlrichs, R.; Kappes, M. M. Small tin cluster anions: Transition from quasispherical to prolate structures. J. Chem. Phys. 2009, 130, 124305, DOI: 10.1063/1.3094320596https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXjvVels7g%253D&md5=f60ebcb722b3c5f2084d5cea89f03396Small tin cluster anions: Transition from quasispherical to prolate structuresOger, Esther; Kelting, Rebecca; Weis, Patrick; Lechtken, Anne; Schooss, Detlef; Crawford, Nathan R. M.; Ahlrichs, Reinhart; Kappes, Manfred M.Journal of Chemical Physics (2009), 130 (12), 124305/1-124305/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The structures and energetics of small tin cluster Snn- anions up to n = 15 were detd. by a combination of d.-functional theory and three different exptl. methods: Ion mobility spectrometry, trapped ion electron diffraction, and collision induced dissocn. We find compact, quasispherical structures up to n = 12. Sn12- is a slightly distorted hollow icosahedron while Sn13- to Sn15- have prolate structures, consisting of merged, hollow, in part incomplete, deltahedral subunits: Sn13- consists of a face-sharing pentagonal bipyramid and tricapped trigonal bipyramid, Sn14- comprises a face-sharing dicapped trigonal prism and capped square-antiprism, and Sn15- consists of two face-sharing tricapped trigonal prisms. (c) 2009 American Institute of Physics.
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597Drebov, N.; Oger, E.; Rapps, T.; Kelting, R.; Schooss, D.; Weis, P.; Kappes, M. M.; Ahlrichs, R. Structures of tin cluster cations Sn3+ to Sn15+. J. Chem. Phys. 2010, 133, 224302, DOI: 10.1063/1.3514907597https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFCqurrF&md5=11e163abda6b186b2cf197cef13d8c93Structures of tin cluster cations Sn3+ to Sn15+Drebov, Nedko; Oger, Esther; Rapps, Thomas; Kelting, Rebecca; Schooss, Detlef; Weis, Patrick; Kappes, Manfred M.; Ahlrichs, ReinhartJournal of Chemical Physics (2010), 133 (22), 224302/1-224302/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We employ a combination of ion mobility measurements and an unbiased systematic structure search with d. functional theory methods to study structure and energetics of gas phase tin cluster cations, Snn+, in the range of n = 3-15. For Sn13+ we also carry out trapped ion electron diffraction measurements to ascertain the results obtained by the other procedures. The structures for the smaller systems are most easily described by idealized point group symmetries, although they are all Jahn-Teller distorted: D3h (trigonal bipyramid), D4h (octahedron), D5h (pentagonal bipyramid) for n = 5, 6, and 7. For the larger systems we find capped D5h for Sn8+ and Sn9+, D3h (tricapped trigonal prism) and D4d (bicapped squared antiprism) plus adatoms for n = 10, 11, 14, and 15. A centered icosahedron with a peripheral atom removed is the dominant motif in Sn12+. For Sn13+ the calcns. predict a family of virtually isoenergetic isomers, an icosahedron and slightly distorted icosahedra, which are about 0.25 eV below two C1 structures. The expts. indicate the presence of two structures, one from the Ih family and a prolate C1 isomer based on fused deltahedral moieties. (c) 2010 American Institute of Physics.
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598Lechtken, A.; Drebov, N.; Ahlrichs, R.; Kappes, M. M.; Schooss, D. Communications: Tin cluster anions (Snn–, n = 18, 20, 23, and 25) comprise dimers of stable subunits. J. Chem. Phys. 2010, 132, 211102, DOI: 10.1063/1.3442411598https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXntF2msrs%253D&md5=26f560c66153c0f59c77fc5b3cfc89d7Communications: Tin cluster anions (Snn-, n = 18, 20, 23, and 25) comprise dimers of stable subunitsLechtken, Anne; Drebov, Nedko; Ahlrichs, Reinhart; Kappes, Manfred M.; Schooss, DetlefJournal of Chemical Physics (2010), 132 (21), 211102/1-211102/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The gas phase structures of tin cluster anions Snn- were studied by a combination of trapped ion electron diffraction and d. functional theory calcns. In the size range of n = 18-25 these clusters comprise dimers of stable subunits. In particular Sn18- and Sn20- are homodimers of Sn9 and Sn10 subunits, resp. In Sn23- two Sn10 units are linked by three addnl. bridging atoms and Sn25- is a heterodimer of Sn10 and Sn15 subunits. This rather unexpected growth mode is rationalized by the extraordinary stability of the building blocks Sn9, Sn10 and Sn15. (c) 2010 American Institute of Physics.
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599Wiesel, A.; Drebov, N.; Rapps, T.; Ahlrichs, R.; Schwarz, U.; Kelting, R.; Weis, P.; Kappes, M. M.; Schooss, D. Structures of medium sized tin cluster anions. Phys. Chem. Chem. Phys. 2012, 14, 234– 245, DOI: 10.1039/C1CP22874A599https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFGmtbvO&md5=19ea7eb6b2a5a1d1b90eb393c2df599aStructures of medium sized tin cluster anionsWiesel, Anne; Drebov, Nedko; Rapps, Thomas; Ahlrichs, Reinhart; Schwarz, Ulrike; Kelting, Rebecca; Weis, Patrick; Kappes, Manfred M.; Schooss, DetlefPhysical Chemistry Chemical Physics (2012), 14 (1), 234-245CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures of medium sized tin cluster anions Snn- (n = 16-29) were detd. by a combination of d. functional theory, trapped ion electron diffraction and collision induced dissocn. (CID). Mostly prolate structures were found with a structural motif based on only three repeatedly appearing subunit clusters, the Sn7 pentagonal bipyramid, the Sn9 tricapped trigonal prism and the Sn10 bicapped tetragonal antiprism. Sn16- and Sn17- are composed of two face connected subunits. In Sn18--Sn20- the subunits form cluster dimers. For Sn21--Sn23- addnl. tin atoms are inserted between the building blocks. Sn24- and Sn25- are composed of a Sn9 or Sn10 connected to a Sn15 subunit, which closely resembles the ground state of Sn15-. Finally, in the larger clusters Sn26--Sn29- addnl. bridging atoms again connect the building blocks. The CID expts. reveal fission as the main fragmentation channel for all investigated cluster sizes. This rather unexpected "pearl-chain" cluster growth mode is rationalized by the extraordinary stability of the building blocks.
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600Cui, L.-F.; Wang, L.-M.; Wang, L.-S. Evolution of the electronic properties of Snn– clusters (n = 4–45) and the semiconductor-to-metal transition. J. Chem. Phys. 2007, 126, 064505, DOI: 10.1063/1.2435347600https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXitFKqsL4%253D&md5=5b08a929c7e938bef3e94c6ff8f067d4Evolution of the electronic properties of Sn-n clusters (n=4-45) and the semiconductor-to-metal transitionCui, Li-Feng; Wang, Lei-Ming; Wang, Lai-ShengJournal of Chemical Physics (2007), 126 (6), 064505/1-064505/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic structure of Snn- clusters (n = 4-45) was examd. using photoelectron spectroscopy at photon energies of 6.424 eV (193 nm) and 4.661 eV (266 nm) to probe the semiconductor-to-metal transition. Well resolved photoelectron spectra were obtained for small Snn- clusters (n ≤ 25), whereas more congested spectra were obsd. with increasing cluster size. A distinct energy gap was obsd. in the photoelectron spectra of Snn- clusters with n ≤ 41, suggesting the semiconductor nature of small neutral Sn clusters. For Snn- clusters with n ≥ 42, the photoelectron spectra became continuous and no well-defined energy gap was obsd., indicating the onset of metallic behavior for the large Snn clusters. The photoelectron spectra thus revealed a distinct semiconductor-to-metal transition for Snn clusters at n = 42. The spectra of small Sn-n clusters (n ≤ 13) were also compared with those of the corresponding Si-n and Ge-n clusters, and similarities were found between the spectra of Sn-n and those of Gen- in this size range, except for Sn-12, which led to the discovery of stannaspherene (the icosahedral Sn2-12) previously [L. F. Cui [et al.], J. Am. Chem. Soc. 128, 8391(2006)].
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601Majumder, C.; Kumar, V.; Mizuseki, H.; Kawazoe, Y. Atomic and electronic structures of neutral and cation Snn (n = 2–20) clusters: A comparative theoretical study with different exchange-correlation functionals. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 035401, DOI: 10.1103/PhysRevB.71.035401601https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVyrtLs%253D&md5=28521cca98c37a6920fff6df976b1d33Atomic and electronic structures of neutral and cation Snn (n = 2-20) clusters: A comparative theoretical study with different exchange-correlation functionalsMajumder, Chiranjib; Kumar, Vijay; Mizuseki, Hiroshi; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (3), 035401/1-035401/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The at. structures and energetics of neutral and singly pos. charged Snn+ (n = 2-20) clusters have been calcd. using a plane wave pseudopotential method under the framework of the generalized gradient approxn. of the d. functional theory as well as by using the hybrid exchange-correlation functionals viz., BLYP, B3LYP and B3PW91 under the LCAO-MO approach. From the results a systematic anal. has been carried out to obtain the physico-chem. properties such as atomization energies, ionization potentials and fragmentation behavior of the neutral and cation clusters. A comparison with the available exptl. data shows that the results obtained from the B3PW91 functional provide an overall good agreement for all the properties calcd. here. Our calcns. show that the dominant channel for the fragmentation of Snn+, n ≤ 11, clusters is the evapn. of an atom such that the charge remains on the rest of the cluster, while for larger clusters, fission into two subclusters becomes more favorable. Raman and IR vibrational spectra have been calcd. for a few selected clusters. These confirm the structural stabilities of the clusters and can provide a way to identify the at. structures from expts.
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602Wu, D.; Du, Q.; Wu, X.; Shi, R.; Sai, L.; Liang, X.; Huang, X.; Zhao, J. Evolution of atomic structures of SnN, and SnN-, and SnNCl- clusters (N = 4-20): Insight from ab initio calculations. J. Chem. Phys. 2019, 150, 174304, DOI: 10.1063/1.5095437602https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXptFGqsrs%253D&md5=00b589b6d40fc1b139dbda05923fd62bEvolution of atomic structures of SnN, SnN- , and SnNCl- clusters (N = 4-20): Insight from ab initio calculationsWu, Di; Du, Qiuying; Wu, Xue; Shi, Ruili; Sai, Linwei; Liang, Xiaoqing; Huang, Xiaoming; Zhao, JijunJournal of Chemical Physics (2019), 150 (17), 174304/1-174304/15CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)An unbiased global search was employed to explore the low-energy structures of SnN, SnN-, and SnNCl- clusters with N = 4-20 atoms based on the genetic algorithm combined with d. functional theory calcns. Some unprecedented low-energy isomers are reported for SnN and SnNCl- clusters. The theor. electronic properties such as binding energy per atom, ionization potential, adiabatic detachment energy, and vertical detachment energy compare well with the exptl. data. Based on the equil. structures, the simulated photoelectron spectra are in good agreement with the exptl. data in the range of N = 4-20. With addn. of a Cl atom on the SnN- cluster, which causes almost no rearrangement on the structural framework, the first peaks in all original photoelectron spectra of SnN- clusters disappear and other peaks nearly retain the original feature at most sizes. (c) 2019 American Institute of Physics.
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603Cui, L.-F.; Huang, X.; Wang, L.-M.; Zubarev, D. Y.; Boldyrev, A. I.; Li, J.; Wang, L.-S. J. Am. Chem. Soc. 2006, 128, 8390– 8391, DOI: 10.1021/ja062052f603https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlvFegtbY%253D&md5=af1cd64b098b0f2ce175ae98458d5693Sn122-: StannasphereneCui, Li-Feng; Huang, Xin; Wang, Lei-Ming; Zubarev, Dmitry Yu.; Boldyrev, Alexander I.; Li, Jun; Wang, Lai-ShengJournal of the American Chemical Society (2006), 128 (26), 8390-8391CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Stannaspherene. The Sn122- cluster is discovered to be a highly stable and highly sym. icosahedral cage bonded by four delocalized radial π bonds and nine delocalized on-sphere σ bonds from the 5p orbitals of the Sn atoms. It has a diam. of 6.1 Å, with a large empty interior vol., and can host most transition metal atoms inside, giving rise to a large class of endohedral chem. building blocks for cluster-assembled nanomaterials.
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604Chen, D.-L.; Tian, W. Q.; Feng, J.-K.; Sun, C.-C. Evidence for d-orbital aromaticity in Sn- and Pb-based clusters: Is Sn122- aromatic?. J. Phys. Chem. A 2007, 111, 8277– 8280, DOI: 10.1021/jp073646n604https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXot12gsr0%253D&md5=f8624d7332db67d31ac0e66ac0808a01Evidence for d-Orbital Aromaticity in Sn- and Pb-Based Clusters: Is Sn122- Aromatic?Chen, De-Li; Tian, Wei Quan; Feng, Ji-Kang; Sun, Chia-ChungJournal of Physical Chemistry A (2007), 111 (33), 8277-8280CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The electronic structures and stabilities of pure M12- and M122- were systematically investigated within d. functional theory. The nucleus-independent chem. shifts (NICSs) of Ih Sn122- and Pb122- are -5.0 and -20.7 ppm, resp., based on B3LYP/aug-cc-pVDZ-PP predictions, whereas the NICS of Sn122- is predicted to be 1.1 ppm by B3LYP/LanL2DZ. A startling conclusion is that the NICS4d of Sn122- and NICS5d of Pb122- are -5.0 and -7.5 ppm, resp., suggesting the significant contribution of the inner d orbitals to the total NICS values. This provides the first quant. evidence for the existence of "d-orbital aromaticity" in Sn- and Pb-based clusters with three-dimensional structures. The d orbitals also contribute to the total NICSs of the K-coordinated clusters. The NICS predictions suggest that larger basis sets including d-orbitals are needed to analyze the aromaticity of some main-group-metal-based clusters (e.g., Sn- and Pb-based clusters) to obtain accurate predictions.
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605Breaux, G. A.; Hillman, D. A.; Neal, C. M.; Jarrold, M. F. Stable copper-tin cluster compositions from high-temperature annealing. J. Phys. Chem. A 2005, 109, 8755– 8759, DOI: 10.1021/jp0501650605https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpvFCmsrw%253D&md5=eb8cccf837332cda06d3b7f890ae6f30Stable copper-tin cluster compositions from high-temperature annealingBreaux, Gary A.; Hillman, Damon A.; Neal, Colleen M.; Jarrold, Martin F.Journal of Physical Chemistry A (2005), 109 (39), 8755-8759CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Copper-doped tin clusters can be thermally annealed to give much more stable compns. with a substantially higher copper/tin ratio. The annealed clusters are only prominent over a narrow range of compns. as CuSn10-15+, Cu2Sn12-18+, Cu3Sn15-21+, Cu4Sn18-(24)+, and Cu5Sn21-(27)+. These compns. are close to those found for WmSin+ clusters and raise the possibility that the CumSnn+ clusters have core-shell geometries like those proposed for the WmSin+ clusters. Increasing the no. of copper atoms causes a change in the dissocn. pattern from the fission processes characteristic of semiconductor clusters to the expulsion of individual atoms, which usually occurs for metal clusters. The change in the fragmentation pattern may result because the clusters rich in copper melt before they dissoc., while the tin clusters dissoc. directly from a solid-like phase.
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606Cui, L. F.; Huang, X.; Wang, L. M.; Li, J.; Wang, L. S. Endohedral stannaspherenes M@Sn12–: A rich class of stable molecular cage clusters. Angew. Chem., Int. Ed. 2007, 46, 742– 745, DOI: 10.1002/anie.200603226606https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlersrw%253D&md5=3e1b46903ad72857470bfdc69a3297deEndohedral stannaspherenes M@Sn12-: a rich class of stable molecular cage clustersCui, Li-Feng; Huang, Xin; Wang, Lei-Ming; Li, Jun; Wang, Lai-ShengAngewandte Chemie, International Edition (2007), 46 (5), 742-745, S742/1-S742/5CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Trapped in a cage: Combined exptl. and theor. evidence shows that the stannaspherene Sn122- can trap a transition-metal or f-element atom (green) to form a stable endohedral cluster. The central metal atom induces very little distortion in the icosahedral cage. The clusters can be viewed as superatoms for use in materials with tunable magnetic, electronic, and chem. properties.
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607Rohrmann, U.; Schäfer, S.; Schäfer, R. Size- and temperature-dependent magnetic response of molecular cage clusters: Manganese-doped tin clusters. J. Phys. Chem. A 2009, 113, 12115– 12121, DOI: 10.1021/jp906140b607https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1eltrbE&md5=5c2792b03f6cbdda80a79f22a1704ec9Size- and Temperature-Dependent Magnetic Response of Molecular Cage Clusters: Manganese-Doped Tin ClustersRohrmann, Urban; Schaefer, Sascha; Schaefer, RolfJournal of Physical Chemistry A (2009), 113 (44), 12115-12121CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Endohedral clusters, formed by incorporating a single Mn atom into a cage of tin atoms, were generated in the gas phase. Mass spectrometry reveals that a cage size of 10 tin atoms is necessary for the efficient incorporation of one Mn atom. Some of the cluster compds. with one Mn atom attached to the tin clusters display large intensities compared to the pure tin clusters, indicating that the compd. clusters are particularly stable. The manganese-doped tin cluster assemblies Mn@Sn12, Mn@Sn13, and Mn@Sn15 were further analyzed within a mol. beam magnetic deflection expt. Although the effect of the magnetic field on the behavior of Mn@Sn12 is quite different from that of Mn@Sn13 and Mn@Sn15, the magnetic dipole moments are the same within the uncertainty of the measurements. Magnetic dipole moments were found in close agreement with the spin quantum no. S = 5/2 predicted by theory for Mn@Sn12, indicating that the magnetic moment of the Mn atom is not quenched. This supports the idea that within a tin cluster cage a single Mn atom can be encapsulated, giving endohedral clusters consisting of a central Mn2+ ion surrounded by a particularly stable Zintl-ion cage SnN2-. The obsd. mol. beam profiles indicate that at a nozzle temp. of 55 K the magnetic moment is strongly locked to the mol. framework of Mn@Sn12; in contrast, the magnetic moment of Mn@Sn13 and Mn@Sn15 tends to align with the magnetic field. The expts. therefore demonstrate that the size of a presumably nonmagnetic cluster cage might have a fundamental influence on the magnetization dynamics of paramagnetic species. The influence of vibrational excitation on the Stern-Gerlach profile of Mn@Sn12 is further analyzed, and the behavior of Mn@Sn12 at elevated nozzle temps. changes continuously toward a nonlocked moment, pointing to size- and temp.-dependent magnetization dynamics.
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608Rohrmann, U.; Schäfer, R. Stern-Gerlach experiments on Fe@Sn12: Magnetic response of a Jahn–Teller distorted endohedrally doped molecular cage cluster. J. Phys. Chem. C 2015, 119, 10958– 10961, DOI: 10.1021/jp510972k608https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXlsFChsA%253D%253D&md5=13c135686743a4ce9e5eaadd9423f5bdStern-Gerlach Experiments on Fe@Sn12: Magnetic Response of a Jahn-Teller Distorted Endohedrally Doped Molecular Cage ClusterRohrmann, Urban; Schaefer, RolfJournal of Physical Chemistry C (2015), 119 (20), 10958-10961CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The magnetic response of the Fe@Sn12 cluster was studied by magnetic beam deflection expts. In contrast to Mn@Sn12, the mol. beam of this cluster is deflected almost exclusively toward increasing field, also at low temps., supposable due to Jahn-Teller induced distortions of the Sn cage. The magnitude of the magnetic dipole moment is extd. from the shift of the beam profile and provides evidence for a (partially quenched) contribution of electronic orbital angular momentum to the magnetic dipole moment.
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609Fuchs, T. M.; Schäfer, R. Double Stern-Gerlach experiments on Mn@Sn12: Refocusing of a paramagnetic superatom. Phys. Rev. A: At., Mol., Opt. Phys. 2018, 98, 063411, DOI: 10.1103/PhysRevA.98.063411There is no corresponding record for this reference.
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610Fuchs, T. M.; Schäfer, R. Effect of vibrational excitation and spin-rotation coupling on Stern-Gerlach experiments: A detailed case study on GdSn15 as an asymmetric rotor. Phys. Rev. A: At., Mol., Opt. Phys. 2019, 100, 012512, DOI: 10.1103/PhysRevA.100.012512There is no corresponding record for this reference.
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611Gleditzsch, M.; Fuchs, T. M.; Schäfer, R. N-doping at the sub-nanoscale: Dielectric and magnetic eesponse of neutral phosphorus-doped tin clusters. J. Phys. Chem. A 2019, 123, 1434– 1444, DOI: 10.1021/acs.jpca.8b12049611https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXisFyktLY%253D&md5=18cf22a441c4ce706f2c25e236bfa09fN-Doping at the Sub-Nanoscale: Dielectric and Magnetic Response of Neutral Phosphorus-Doped Tin ClustersGleditzsch, Martin; Fuchs, Thomas M.; Schaefer, RolfJournal of Physical Chemistry A (2019), 123 (7), 1434-1444CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Doped semiconductors play a prevalent role in all aspects of modern technol. Because of the trend for smaller and smaller devices, we have investigated N-doping at the sub-nanoscale. For that purpose, we present mol. beam elec. and magnetic deflection expts. on SnNP (N = 6-12) and SnNP2 (N = 7-12) clusters combined with quantum chem. calcns. and classical beam deflection simulations. The theor. identified and exptl. confirmed global min. structures resemble the valence-isoelectronic pure tin anions/dianions very closely, while each phosphorus dopant occupies the site of a tin atom. In Stern-Gerlach expts., the single-doped clusters show a partial atom-like deflection behavior with total electronic angular momentum J = 1/2 whereas the results for the double-doped species suggest singlet states. This is in full agreement with quantum chem. results. The effect of vibrational excitation on magnetic and elec. deflection expts. is examd. Our results provide insight into how the elec., magnetic, and structure properties are affected by n-doping at the sub-nanoscale.
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612Gleditzsch, M.; Pašteka, L. F.; Götz, D. A.; Shayeghi, A.; Johnston, R. L.; Schäfer, R. Gold doping of tin clusters: exo-vs. endohedral complexes. Nanoscale 2019, 11, 12878– 12888, DOI: 10.1039/C9NR03233A612https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXht1Kgtr%252FK&md5=d127655532ec13b724376e2475cd3647Gold doping of tin clusters: exo- vs. endohedral complexesGleditzsch, Martin; Pasteka, Lukas F.; Goetz, Daniel A.; Shayeghi, Armin; Johnston, Roy L.; Schaefer, RolfNanoscale (2019), 11 (27), 12878-12888CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)We present mol. beam elec. deflection expts. on neutral gold-doped tin clusters. The exptl. SnNAu (N = 6-16) cluster beam profiles are interpreted by means of classical trajectory simulations supplied, with cluster structures generated by a genetic algorithm based on d. functional theory. The combined exptl. and theor. anal. confirms that at least nine tin atoms are necessary to form a cage that is capable of encapsulating a gold atom, with high symmetry only marginally distorted by the gold atom. Two-component DFT calcns. reveal that for some clusters spin-orbit effects are necessary to properly describe these species. Partial charge anal. methods predict the presence of charge transfer effects from the tin host to the dopant, resulting in a neg. charged gold atom.
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613Gleditzsch, M.; Jäger, M.; Pašteka, L. F.; Shayeghi, A.; Schäfer, R. Doping effects on the geometric and electronic structure of tin clusters. Phys. Chem. Chem. Phys. 2019, 21, 24478– 24488, DOI: 10.1039/C9CP05124D613https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitV2mtr7I&md5=876811dc62b78f04ccefedc39b16224cDoping effects on the geometric and electronic structure of tin clustersGleditzsch, Martin; Jaeger, Marc; Pasteka, Lukas F.; Shayeghi, Armin; Schaefer, RolfPhysical Chemistry Chemical Physics (2019), 21 (44), 24478-24488CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Mol. beam elec. deflection expts. on neutral single copper-doped tin clusters are presented at different cryogenic nozzle temps. The exptl. cluster beam profiles SnNCu (N = 9-16) are compared with classical rotational dynamic simulations of globally optimized structures obtained by a genetic algorithm based on d. functional theory. The formation of endohedral complexes with comparable geometry to manganese- and gold-doped tin is confirmed. Theor. methods predict ionic structures of the type Cuδ-@SnNδ+ with electron transfer from the tin cage to the central copper dopant. This behavior is discussed based on a MO picture particularly with respect to other transition metal tetrel complexes.
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614Liu, C.; Jin, X.; Li, L.; Xu, J.; McGrady, J.; Sun, Z. Synthesis and structure of a family of rhodium polystannide clusters [Rh@Sn10]3–, [Rh@Sn12]3–, [Rh2@Sn17]6– and the first triply-fused stannide, [Rh3@Sn24]5–. Chem. Sci. 2019, 10, 4394– 4401, DOI: 10.1039/C8SC03948H614https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXksFemtbk%253D&md5=c581fe95eacc5dac804796b585bfa3d1Synthesis and structure of a family of rhodium polystannide clusters [Rh@Sn10]3-, [Rh@Sn12]3-, [Rh2@Sn17]6- and the first triply-fused stannide, [Rh3@Sn24]5-Liu, Chao; Jin, Xiao; Li, Lei-Jiao; Xu, Jun; McGrady, John E.; Sun, Zhong-MingChemical Science (2019), 10 (16), 4394-4401CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)Through relatively subtle changes in reaction conditions, we have been able to isolate four distinct Rh/Sn cluster compds., [Rh@Sn10]3-, [Rh@Sn12]3-, [Rh2@Sn17]6- and [Rh3@Sn24]5-, from the reaction of K4Sn9 with [(COE)2Rh(μ-Cl)]2(COE = cyclooctene). The last of these has a hitherto unknown mol. topol., an edge-fused polyhedron contg. three Rh@Sn10 subunits, and represents the largest endohedral Group 14 Zintl cluster yet to have been isolated from soln. DFT has been used to place these new species in the context of known cluster chem. ESI-MS expts. on the reaction mixts. reveal the ubiquitous presence of {RhSn8} fragments that may play a role in cluster growth.
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615Tai, T. B.; Tam, N. M.; Nguyen, M. T. Evolution of structures and stabilities of zinc-doped tin clusters SnnZn, n = 1–12. Three-dimensional aromaticity of the magic clusters Sn10Zn and Sn12Zn. Chem. Phys. 2011, 388, 1– 8, DOI: 10.1016/j.chemphys.2011.06.041615https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtF2rsLfF&md5=11deebbd68e7181fb0bf5c53cf7b85e1Evolution of structures and stabilities of zinc-doped tin clusters SnnZn, n = 1-12. Three-dimensional aromaticity of the magic clusters Sn10Zn and Sn12ZnTai, Truong-Ba; Tam, Nguyen-Minh; Nguyen, Minh-ThoChemical Physics (2011), 388 (1-3), 1-8CODEN: CMPHC2; ISSN:0301-0104. (Elsevier B.V.)Small zinc-doped tin clusters SnnZn, n = 1-12, are studied using DFT and CCSD(T) methods. The isomers are located using a stochastic search algorithm. The growth mechanism can be formulated as follows: (i) small clusters SnnZn with n ≤ 8 are formed by capping Zn on a surface of Snn, (ii) a competition between exohedral and endohedral structures appears at n = 9 and 10, from which the endohedral structures become predominant, (iii) for n = 11 and 12, the clusters are formed by encapsulating Zn into the empty cages Snn. Icosahedral Sn12Zn (I h) and Sn10Zn (D 4d) are magic clusters with large HOMO-LUMO gaps, high binding energies and embedding energies. While both Sn12Zn and Sn10Zn clusters can be considered to be spherically arom. with 8 valence π-electrons that satisfy the electron count rule of 2(N + 1)2, the enhanced stability of Sn12Zn (I h) can further be rationalized in terms of its closed crystal field splitting shell.
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616Bai, Y.-J.; Deng, K.-M.; Shaoa, J.-L.; Xua, N. Structures, stabilities and electronic properties of MSn10 (M = Li, Be, B, Ca). J. At. Mol. Sci. 2018, 5, 217– 230, DOI: 10.4208/jams.030114.052814aThere is no corresponding record for this reference.
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617Zdetsis, A. D. Rationalizing and functionalizing stannaspherene: Very stable stannaspherene “alloys”. J. Chem. Phys. 2009, 131, 224310, DOI: 10.1063/1.3267046617https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFGjt73K&md5=88b26c179e667ee1808800acaed036ccRationalizing and functionalizing stannaspherene: Very stable stannaspherene "alloys"Zdetsis, Aristides D.Journal of Chemical Physics (2009), 131 (22), 224310/1-224310/11CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)It is illustrated here by ab initio calcns. based on d. functional theory and other high level methods that the high stability of the icosahedral Sn122- dianion known as stannaspherene, reflects stability toward ionization rather than cohesion. This could be also connected with novel fluxional rearrangements and paths of Sn111- leading eventually to Sn122- involving charge transfer. In view of the very similar structural and electronic properties with the corresponding isovalent borane (B12H12)2-, it is demonstrated that stannaspherene can be further rationalized and functionalized on the basis of an isolobal analogy between group 14 clusters and isovalent boranes, carboranes, and bisboranes. Such analogy is of the same nature with analogous isolobal and isovalent similarities between silicon, hydrogenated silicon-carbon clusters and deltahedral boranes and carboranes, which the present author, scoptically and synoptically, has described as the "boron connection.". It is predicted and verified theor.: First, that the isovalent Bi2Sn10 and Sb2Sn10 clusters, considered as the microscopic analogs of tin-bismuth alloys, are very stable (more stable than stannaspherene itself) very sym. and isolobal to Sn122-; and second, that embedded clusters of the form M@Sn122- and M@Bi2Sn10 (M = Pt,Pd) are very stable and highly sym. (Ih and D5d resp.) with large HOMO-LUMO gaps and very large embedding energies of the order of 5-6 eV. It is furthermore predicted that Pt@Sn122- and Pt@Bi2Sn10 can be synthesized in view of their higher stability compared to Pt@Pb122- which has already been synthesized. The marginal energy difference of 0.03 eV between the meta- and the para-isomer of Bi2Sn10 indicates a fluxional behavior with respect to Bi-Sn interchange which should be related with the Sn121- fluxionality leading eventually to Sn122-. This rearrangement is also assocd. with a strange arom. behavior. The same type of Bi-Sn fluxionality is also encountered in higher energy structures. Due to the "inert pair effect" in tin, the validity of the isolobal analogy is much stronger and fully valid compared to isovalent species based on germanium or silicon, such as Ge122-, Bi22Ge10, and Ge10C2H2 and Si122-, Bi2Si10, and Si10C2H2. The present ideas are in full agreement with available expts. and suggest even further functionalization of stannaspherene, analogous to metalloboranes, metallocarboranes, and stannaboranes with several potential applications. (c) 2009 American Institute of Physics.
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618Matxain, J. M.; Piris, M.; Formoso, E.; Mercero, J. M.; Lopez, X.; Ugalde, J. M. Endohedral stannaspherenes Mn@Sn12 and its dimer: Ferromagnetic or antiferromagnetic?. ChemPhysChem 2007, 8, 2096– 2099, DOI: 10.1002/cphc.200700428618https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtF2qtbnL&md5=24f37ea335b1b28cb4f4e8c999bf6984Endohedral stannaspherenes Mn@Sn12 and its dimer: ferromagnetic or antiferromagnetic?Matxain, Jon M.; Piris, Mario; Formoso, Elena; Mercero, Jose M.; Lopez, Xabier; Ugalde, Jesus M.ChemPhysChem (2007), 8 (14), 2096-2099CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)The structural and electronic properties of the neutral Mn@Sn12 cluster and its dimer are investigated. All geometries were fully optimized using the hybrid metaGGA functional MPWB1K within d. functional theory, combined with the relativistic compact effective core potentials and shared-exponent basis set of Stevens et al. The estns. indicate that the inner manganese atom loses two valence electrons to the cage upon encapsulation. This confirms the assumption that endohedral stannaspherenes contain the dianionic Sn122- cage moiety. Based on the magnetic exchange coupling consts., J, of three isomers of the [Mn@Sn12]2 dimer, an anti- ferromagnetic interaction is favored.
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619Kandalam, A. K.; Chen, G.; Jena, P. Unique magnetic coupling between Mn doped stannaspherenes Mn@Sn12. Appl. Phys. Lett. 2008, 92, 143109, DOI: 10.1063/1.2896608619https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXkvFyqtr8%253D&md5=e45171ebf0b770172f17d00870e74c8cUnique magnetic coupling between Mn doped stannaspherenes Mn@Sn12Kandalam, Anil K.; Chen, Gang; Jena, PuruApplied Physics Letters (2008), 92 (14), 143109/1-143109/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)We report the d. functional theory based study of the interaction between two Mn doped stannaspherenes (Mn@Sn12). The calcd. results show that Mn@Sn12 cluster is not only highly stable and carry a high magnetic moment, but these clusters retain their structural identity and form a stable dimer cluster. Most importantly, the magnetic coupling between the Mn@Sn12 clusters depends on the relative orientation of the cages. In addn., ab initio mol. dynamics calcns. show that the dimer cluster is stable at room temp. These results are expected to trigger further investigations on highly stable bimetallic magnetic cage complexes. (c) 2008 American Institute of Physics.
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620Chen, X.; Deng, K.; Liu, Y.; Tang, C.; Yuan, Y.; Tan, W.; Wang, X. The geometric, optical, and magnetic properties of the endohedral stannaspherenes M@Sn12 (M = Ti, V, Cr, Mn, Fe, Co, Ni). J. Chem. Phys. 2008, 129, 094301, DOI: 10.1063/1.2969111620https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtV2gs7%252FM&md5=23aa8efe1c0e44cf8f43019beb4f769aThe geometric, optical, and magnetic properties of the endohedral stannaspherenes M@Sn12 (M=Ti, V, Cr, Mn, Fe, Co, Ni)Chen, Xuan; Deng, Kaiming; Liu, Yuzhen; Tang, Chunmei; Yuan, Yongbo; Tan, Weishi; Wang, XinJournal of Chemical Physics (2008), 129 (9), 094301/1-094301/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The geometric, optical, and magnetic properties of the M@Sn12 clusters (M = Ti, V, Cr, Mn, Fe, Co, Ni) are studied using the relativistic d.-functional method. The geometric optimization shows that the ground states of these clusters are probably very close to the Ih structure. Our calcns. demonstrate that the optical gaps of the M@Sn12 can be tuned from IR to green, and the magnetic moments of them vary from 2 μB to 5 μB by doping d transition metal atoms into Sn12 cage, suggesting that M@Sn12 could be a new class of potential nanomaterials with tunable magnetic and optical properties. (c) 2008 American Institute of Physics.
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621Dognon, J.-P.; Clavaguéra, C.; Pyykkö, P. Chemical properties of the predicted 32-electron systems Pu@Sn12 and Pu@Pb12. C. R. Chim. 2010, 13, 884– 888, DOI: 10.1016/j.crci.2010.05.012621https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXpvFKlu74%253D&md5=0aebab2367d82aa7269ceae9568ec0d6Chemical properties of the predicted 32-electron systems Pu@Sn12 and Pu@Pb12Dognon, Jean-Pierre; Clavaguera, Carine; Pyykkoe, PekkaComptes Rendus Chimie (2010), 13 (6-7), 884-888CODEN: CRCOCR; ISSN:1631-0748. (Elsevier Masson SAS)The electronic structures, as well as spectroscopic and thermodn. properties of the title Pu@M12 clusters, are considered at the d. functional theory level. In both cases, a Pu2+ ion is encapsulated in an icosahedral, stanna- or plumbaspherene M2-12 cage. As suggested before for M = Pb, both systems are reported to follow a 32-electron principle for the central atom.
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622Joshi, M.; Chandrasekar, A.; Ghanty, T. K. Theoretical investigation of M@Pb122– and M@Sn122– zintl clusters (M = Lrn+, Lun+, La3+, Ac3+ and n = 0, 1, 2, 3). Phys. Chem. Chem. Phys. 2018, 20, 15253– 15272, DOI: 10.1039/C8CP01056K622https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXos1Wgurg%253D&md5=8dfeee6277c01dcc88d3e3d491ad9b16Theoretical investigation of M@Pb122- and M@Sn122- Zintl clusters (M = Lrn+, Lun+, La3+, Ac3+ and n = 0, 1, 2, 3)Joshi, Meenakshi; Chandrasekar, Aditi; Ghanty, Tapan K.Physical Chemistry Chemical Physics (2018), 20 (22), 15253-15272CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The positions of lawrencium (Lr), lutetium (Lu), actinium (Ac) and lanthanum (La) in the periodic table have been a controversial topic for quite some time. According to studies carried out by different groups with their justifications, these elements may potentially be placed in the d-block, p-block or all four in a 15 element f-block. The present work looks into this issue from a new perspective, which involves encapsulation of these four elements into Zintl ion clusters, Pb122- and Sn122-, followed by the detn. of the structural, thermodn. and electronic properties of these endohedral M@Pb122- and M@Sn122- clusters (M = Lrn+, Lun+ with n = 0, 1, 2, 3) using first principles based d. functional theory (DFT). These parameters are compared with similar clusters encapsulated La3+ and Ac3+ ions in order to seek out similarities and differences to draw conclusions about their placement in the periodic table. For the first time the structural, energetic, and electronic properties of these metal atom/ion encapsulated Pb122- and Sn122- clusters have been investigated thoroughly. Structural parameters such as bond distances, geometry and symmetry, electronic properties viz. the d. of states, the MO ordering, the electron localization function, bond crit. point properties and charge distributions have been analyzed. Addnl., the thermodn. property of the binding energy during the encapsulation process has also been calcd. All M@Pb12+ and M@Sn12+ (M = Lr and Lu) clusters form stable 18 bonding electron magic no. systems with shell closing. They show neg. values of binding energy and relatively large HOMO-LUMO energy gaps indicating the stability of such clusters. All the calcd. parameters for Lr encapsulated clusters closely match with the corresponding calcd. parameters of Lu encapsulated clusters, confirming the similarity between Lr and Lu metal atoms in various oxidn. states, though their at. ground state valence electronic configurations are different. The effect of spin orbit coupling has also been investigated using the ZORA approach. It is interesting to discover that La and Ac showed striking similarities to Lr and Lu with respect to all the properties investigated and have formed a stable 18-electron system.
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623Wang, J. Q.; Stegmaier, S.; Wahl, B.; Faessler, T. F. Step-by-step synthesis of the endohedral stannaspherene [Ir@Sn12]3– via the capped cluster anion [Sn9Ir(cod)]3–. Chem. - Eur. J. 2010, 16, 1793– 1798, DOI: 10.1002/chem.200902815623https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVKjtrc%253D&md5=7a88a02eb18eebffa65e5346b49ebae0Step-by-Step Synthesis of the Endohedral Stannaspherene [Ir@Sn12]3- via the Capped Cluster Anion [Sn9Ir(cod)]3-Wang, Jian-Qiang; Stegmaier, Saskia; Wahl, Bernhard; Faessler, Thomas F.Chemistry - A European Journal (2010), 16 (6), 1793-1798, S1793/1-S1793/4CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The endohedral stannaspherene cluster anion [Ir@Sn12]3- was synthesized in two steps. The reaction of K4Sn9 with [IrCl(cod)]2 (cod: 1,5-cyclooctadienyl) in ethylenediamine (en) soln. first yielded the [K(2,2,2-crypt)]+ salt (2,2,2-crypt: 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) of the capped cluster anion [Sn9Ir(cod)]3-. Subsequently, crystals of this compd. were dissolved in en, followed by the addn. of triphenylphosphine or 1,2-bis(diphenylphosphino)ethane and treatment at elevated temps. [Ir@Sn12]3- was obtained and characterized as the [K(2,2,2-crypt)]+ salt. The isolation of [Sn9Ir(cod)]3- as an intermediate product establishes that the formation of the stannaspherene [Ir@Sn12]3- occurs through the oxidn. of [Sn9Ir(cod)]3-. Among the structurally characterized tetrel cluster anions, [Ir@Sn12]3- is a unique example of a stannaspherene, and one of the rare spherical clusters encapsulating a metal atom that is not a member of Group 10. Single-crystal structure detn. shows that the novel Zintl ion cluster has nearly perfect icosahedral Ih point symmetry.
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624Shvartsburg, A. A.; Jarrold, M. F. Transition from covalent to metallic behavior in group-14 clusters. Chem. Phys. Lett. 2000, 317, 615– 618, DOI: 10.1016/S0009-2614(99)01416-5624https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhtFaht7s%253D&md5=f5232c1cc7a5a07e4aff11ef836c9a1dTransition from covalent to metallic behavior in Group IVA element clustersShvartsburg, A. A.; Jarrold, M. F.Chemical Physics Letters (2000), 317 (6), 615-618CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)We have probed the structures of Pbn cations up to n = 32 using ion mobility measurements. These species assume compact near-spherical morphologies for all sizes studied. This behavior is characteristic of clusters of the metallic elements. Silicon, germanium, and tin clusters in the same size range have previously been found to adopt prolate geometries produced by stacking tricapped trigonal prism units. So the transition to 'normal' metal cluster growth in the Group IVA elements occurs between tin and lead, one row lower than the transition from covalent to metallic bonding in the bulk solids under ambient conditions.
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625Senz, V.; Fischer, T.; Oelßner, P.; Tiggesbäumker, J.; Stanzel, J.; Bostedt, C.; Thomas, H.; Schöffler, M.; Foucar, L.; Martins, M. Core-hole screening as a probe for a metal-to-nonmetal transition in lead clusters. Phys. Rev. Lett. 2009, 102, 138303, DOI: 10.1103/PhysRevLett.102.138303625https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXktFSjs7c%253D&md5=836c8ef189545af5412b58357b573e67Core-Hole Screening as a Probe for a Metal-to-Nonmetal Transition in Lead ClustersSenz, V.; Fischer, T.; Oelssner, P.; Tiggesbaumker, J.; Stanzel, J.; Bostedt, C.; Thomas, H.; Schoeffler, M.; Foucar, L.; Martins, M.; Neville, J.; Neeb, M.; Moeller, Th.; Wurth, W.; Ruehl, E.; Doerner, R.; Schmidt-Boecking, H.; Eberhardt, W.; Gantefoer, G.; Treusch, R.; Radcliffe, P.; Meiwes-Broer, K.-H.Physical Review Letters (2009), 102 (13), 138303/1-138303/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Metal clusters serve as model systems to study basic problems of electronic correlation. Vacuum UV light from the free-electron laser FLASH ionizes 5d electrons from mass-sepd. neg. charged clusters, thus transiently leading to core-ionized neutral systems. Shielding of the core hole affects the electron binding energy. From the strong deviation from expectations of the metallic droplet and jellium models the authors conclude on reduced electronic shielding once the cluster size falls .ltorsim.20 atoms. This suggests a metal-to-nonmetal transition, in agreement with previous local d. approxn. calcns.
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626Götz, D.; Shayeghi, A.; Johnston, R.; Schwerdtfeger, P.; Schäfer, R. Influence of spin-orbit effects on structures and dielectric properties of neutral lead clusters. J. Chem. Phys. 2014, 140, 164313, DOI: 10.1063/1.4872369626https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2cnptFyktA%253D%253D&md5=74ef322c32955da4fbf7df57b215d11fInfluence of spin-orbit effects on structures and dielectric properties of neutral lead clustersGotz D A; Shayeghi A; Schafer R; Johnston R L; Schwerdtfeger PThe Journal of chemical physics (2014), 140 (16), 164313 ISSN:.Combining molecular beam electric deflection experiments and global optimization techniques has proven to be a powerful tool for resolving equilibrium structures of neutral metal and semiconductor clusters. Herein, we present electric molecular beam deflection experiments on PbN (N = 7-18) clusters. Promising structures are generated using the unbiased Birmingham Cluster Genetic Algorithm approach based on density functional theory. The structures are further relaxed within the framework of two-component density functional theory taking scalar relativistic and spin orbit effects into account. Quantum chemical results are used to model electric molecular beam deflection profiles based on molecular dynamics calculations. Comparison of measured and simulated beam profiles allows the assignment of equilibrium structures for the most cluster sizes in the examined range for the first time. Neutral lead clusters adopt mainly spherical geometries and resemble the structures of lead cluster cations apart from Pb10. Their growth pattern deviates strongly from the one observed for tin and germanium clusters.
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627Götz, D. A.; Shayeghi, A.; Johnston, R. L.; Schwerdtfeger, P.; Schäfer, R. Structural evolution and metallicity of lead clusters. Nanoscale 2016, 8, 11153– 11160, DOI: 10.1039/C6NR02080A627https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28bpvFGqtA%253D%253D&md5=c662b1708b39c56133472b720d7f35c2Structural evolution and metallicity of lead clustersGotz Daniel A; Shayeghi Armin; Johnston Roy L; Schwerdtfeger Peter; Schafer RolfNanoscale (2016), 8 (21), 11153-60 ISSN:.The evolution of the metallic state in lead clusters and its structural implications are subject to ongoing discussions. Here we present molecular beam electric deflection studies of neutral PbN (N = 19-25, 31, 36, 54) clusters. Many of them exhibit dipole moments or anomalies of the polarizability indicating a non-metallic state. In order to resolve their structures, the configurational space is searched using the Pool Birmingham Cluster Genetic algorithm based on density functional theory. Spin-orbit effects on the geometries and dipole moments are taken into account by further relaxing them with two-component density functional theory. Geometries and dielectric properties from quantum chemical calculations are then used to simulate beam deflection profiles. Structures are assigned by the comparison of measured and simulated beam profiles. Energy gaps are calculated using time-dependent density functional theory. They are compared to Kubo gaps, which are an indicator of the metallicity in finite particles. Both, experimental and theoretical data suggest that lead clusters are not metallic up to at least 36 atoms.
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628Wang, B.; Zhao, J.; Chen, X.; Shi, D.; Wang, G. Atomic structures and covalent-to-metallic transition of lead clusters Pbn (n = 2–22). Phys. Rev. A: At., Mol., Opt. Phys. 2005, 71, 033201, DOI: 10.1103/PhysRevA.71.033201628https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjsFGmur8%253D&md5=60a1376bf378419738324370c5f2bd92Atomic structures and covalent-to-metallic transition of lead clusters Pbn (n=2-22)Wang, Baolin; Zhao, Jijun; Chen, Xiaoshuang; Shi, Daning; Wang, GuanghouPhysical Review A: Atomic, Molecular, and Optical Physics (2005), 71 (3-B), 033201/1-033201/7CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)The lowest-energy structures and electronic properties of the lead clusters are studied by d.-functional-theory calcns. with Becke-Lee-Yang-Parr gradient correction. The lowest-energy structures of Pbn (n = 2-22) clusters are detd. from a no. of structural isomers, which are generated from empirical genetic algorithm simulations. The competition between atom-centered compact structures and layered stacking structures leads to the alternative appearance of the two types of structures as global min. The size evolution of geometric and electronic properties from covalent bonding towards bulk metallic behavior in Pb clusters is discussed.
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629Cui, L.-F.; Huang, X.; Wang, L.-M.; Li, J.; Wang, L.-S. J. Phys. Chem. A 2006, 110, 10169– 10172, DOI: 10.1021/jp063617x629https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XnsFemt7o%253D&md5=bfb1655a111df852d00cbfff45f078a8Pb122-: PlumbasphereneCui, Li-Feng; Huang, Xin; Wang, Lei-Ming; Li, Jun; Wang, Lai-ShengJournal of Physical Chemistry A (2006), 110 (34), 10169-10172CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Although Si or Ge are not known to form empty cage clusters such as the fullerenes, we recently found a unique 12-atom icosahedral tin cluster, Sn122- (stannaspherene). Here we report photoelectron spectroscopy and theor. evidence that Pb122- is also a highly stable icosahedral cage cluster and bonded by four delocalized radial π bonds and nine delocalized on-sphere σ bonds from the 6p orbitals of the Pb atoms. Following Sn122-, we coin a name, plumbaspherene, for the highly stable and nearly spherical Pb122- cluster, which is expected to be stable in soln. and the solid state. Plumbaspherene has a diam. of ∼6.3 Å with an empty interior vol. large enough to host most transition metal atoms, affording a new class of endohedral clusters.
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630Zhang, X.; Li, G.; Xing, X.; Zhao, X.; Tang, Z.; Gao, Z. Formation of binary alloy cluster ions from group-14 elements and cobalt and comparison with solid-state alloys. Rapid Commun. Mass Spectrom. 2001, 15, 2399– 2403, DOI: 10.1002/rcm.530630https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjtVKhtg%253D%253D&md5=97527381ef4b7386a1e9aa2da6056b82Formation of binary alloy cluster ions from group-14 elements and cobalt and comparison with solid-state alloysZhang, Xia; Li, Guoliang; Xing, Xiaopeng; Zhao, Xiang; Tang, Zichao; Gao, ZhenRapid Communications in Mass Spectrometry (2001), 15 (24), 2399-2403CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)By using laser ablation on mixts. of transition metal Co and group-14 elements, binary alloy cluster anions were produced while no binary alloy cluster cations were detected, and the homo-cluster cations of group-14 elements appeared at very low abundance. The differences between clustering abilities of Ge, Sn and lead with Co are described, and the chem. bonds in the binary alloy cluster anions appear to indicate a transition from covalent to metal bonds. The cluster anion [CoPb10]- appears in very high abundance (magic no.), and an endohedral structure is proposed for this cluster. The cluster anion [CoPb12]-, also representing a magic no., probably has an icosahedral structure. Compared with solid-state Co/Ge binary alloys, the compns. of most binary alloy cluster anions are Ge-rich, in which the covalent bonds are predominant.
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631Xing, X.; Tian, Z.; Liu, H.; Tang, Z. Magic bimetallic cluster anions of M/Pb (M = Au, Ag and Cu) observed and analyzed by laser ablation and time-of-flight mass spectrometry. Rapid Commun. Mass Spectrom. 2003, 17, 1411– 1415, DOI: 10.1002/rcm.1063631https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXltFejtbg%253D&md5=2ab4e406be173e20eb329f5e624a792cMagic bimetallic cluster anions of M/Pb (M = Au, Ag and Cu) observed and analyzed by laser ablation and time-of-flight mass spectrometryXing, Xiaopeng; Tian, Zhixin; Liu, Hongtao; Tang, ZichaoRapid Communications in Mass Spectrometry (2003), 17 (13), 1411-1415CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)By using laser ablation on mixts. of coinage metals M (Cu, Ag, Au) and lead, M/Pb binary cluster anions contg. up to tens of atoms were produced and analyzed. Most of the magic clusters discovered can be described based on the electron shell models which were deduced from simple homogeneous metal cluster systems. The clustering activities of coinage metals and lead were also compared with the properties of their bulk binary alloys.
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632Schäfer, S.; Schäfer, R. New molecular cage clusters of Pb by encapsulation of Mg. ChemPhysChem 2008, 9, 1925– 1929, DOI: 10.1002/cphc.200800264632https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1cngsVGqtg%253D%253D&md5=35bc5b8232a18ba3551dc771f3201e49New molecular cage clusters of Pb by encapsulation of MgSchafer Sascha; Schafer RolfChemphyschem : a European journal of chemical physics and physical chemistry (2008), 9 (13), 1925-9 ISSN:.Endohedral clusters formed from the Zintl ions Pb(10) (2-) and Pb(12) (2-) are particularly stable and therefore suitable for the assembly of larger aggregates. We therefore investigate the formation of Mg-doped lead clusters in the gas phase, and demonstrate that a whole series of new molecular cage clusters of lead can be generated by encapsulation of magnesium. Mass spectrometry reveals that some of the cluster compounds, with one and two Mg atoms attached to the lead clusters, display large intensities compared to the pure lead clusters, which indicates that the compound clusters are particularly stable. The magnesium-doped lead-cluster assemblies were further analyzed within a molecular-beam electric deflection experiment. Almost vanishing permanent dipole moments for MgPb(10-16) support the idea that a single Mg atom could be encapsulated within a highly symmetric lead cage, which results in structures with not only enhanced stability but also increased symmetry compared to the pure lead clusters Pb(N).
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633Grubisic, A.; Wang, H.; Li, X.; Ko, Y.-J.; Kocak, F. S.; Pederson, M. R.; Bowen, K. H.; Eichhorn, B. W. Photoelectron spectroscopic and computational studies of the Pt@Pd10- and Pt@Pd121-/2- anions. Proc. Natl. Acad. Sci. U. S. A. 2011, 108, 14757– 14762, DOI: 10.1073/pnas.1105052108633https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFyktLnF&md5=241bb599d8f017fb7edf3cc5ce4aa82cPhotoelectron spectroscopic and computational studies of the Pt@Pb101- and Pt@Pb121-/2- anionsGrubisic, Andrej; Wang, Haopeng; Li, Xiang; Ko, Yeon-Jae; Kocak, F. Sanem; Pederson, Mark R.; Bowena, Kit H.; Eichhorn, Bryan W.Proceedings of the National Academy of Sciences of the United States of America (2011), 108 (36), 14757-14762, S14757/1-S14757/2CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)A combination of anion photoelectron spectroscopy and d. functional theory calcns. has elucidated the geometric and electronic structure of gas-phase endohedral Pt/Pb cage cluster anions. The anions, Pt@Pb101- and Pt@Pb121- were prepd. from "preassembled" clusters generated from cryst. samples of [K(2,2,2-crypt)]2[Pt@Pb12] that were brought into the gas phase using a unique IR desorption/photoemission anion source. The use of cryst. [K(2,2,2-crypt)]2[Pt@Pb12] also provided access to K[Pt@Pbn]- anions in the gas phase (i.e., the K+ salts of the Pt@Pbn2- anions). Anion photoelectron spectra of Pt@Pb101-, Pt@Pb121-, and K[Pt@Pb12]1- are presented. Extensive d. functional theory calcns. on Pt@Pb103-/2-/1-/0 and Pt@Pb122-/1- provided candidate structures and anion photoelectron spectra for Pt@Pb101- and Pt@Pb121-. Together, the calcd. and measured photoelectron spectra show that Pt@Pb101- and Pt@Pb121- endohedral complexes maintain their resp. D4d and slightly distorted Ih symmetries in the gas phase even for the charge states with open shell character. Aside from the fullerenes, the Pt@Pb122- endohedral complex is the only bare cluster that has been structurally characterized in the solid state, soln., and the gas phase.
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634Bhattacharyya, S.; Nguyen, T. T.; De Haeck, J.; Hansen, K.; Lievens, P.; Janssens, E. Mass-selected photodissociation studies of AlPbn+ clusters (n = 7–16): Evidence for the extraordinary stability of AlPb10+ and AlPb12+. Phys. Rev. B: Condens. Matter Mater. Phys. 2013, 87, 054103, DOI: 10.1103/PhysRevB.87.054103634https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltlGktb8%253D&md5=06e42fd40ea888721b63c9dbd1e0494fMass-selected photodissociation studies of AlPbn+ clusters (n = 7-16): evidence for the extraordinary stability of AlPb10+ and AlPb12+Bhattacharyya, Soumen; Nguyen, Thanh Tung; De Haeck, Jorg; Hansen, Klavs; Lievens, Peter; Janssens, EwaldPhysical Review B: Condensed Matter and Materials Physics (2013), 87 (5), 054103/1-054103/7CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors report fragmentation pathways and dissocn. energies of AlPbn+ (n = 7-16) clusters. The clusters are produced with pulsed laser vaporization and studied in a supersonic mol. beam setup. They are mass selected and photodissociated with 532 and 355 nm laser light. Photofragments are thereafter mass sepd. in a tandem reflectron time-of-flight mass spectrometer. Bare Pbn+ (n = 8-16) clusters preferentially evap. Pb atoms, with the exception of Pb15+ that fragments by loss of a Pb2 dimer to form the stable Pb13+ cluster. The smallest AlPbn+ (n = 7-11) clusters also show mainly at. Pb evapn., whereas the favored fragmentation pathway of the larger clusters (n = 12-16) involves Pb2 and Pb3 fragments. AlPb10+ and AlPb12+ are the most intense fragments of several larger cluster sizes, demonstrating the high stability of these two sizes. Dissocn. energies corresponding to the most facile fragmentation channel of AlPbn+ (n = 11-15) are bracketed from the measured laser fluence dependencies of the fragment intensities using constraints imposed by unimol. reaction rates.
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635Xie, H.; Qin, Z.; Wu, X.; Tang, Z.; Jiang, L. Photoelectron velocity-map imaging signature of structural evolution of silver-doped lead Zintl anions. J. Chem. Phys. 2012, 137, 064318, DOI: 10.1063/1.4745000635https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFOrsbfP&md5=c773971bf8d7102040ed6ac0f2061a84Photoelectron velocity-map imaging signature of structural evolution of silver-doped lead Zintl anionsXie, Hua; Qin, Zhengbo; Wu, Xia; Tang, Zichao; Jiang, LingJournal of Chemical Physics (2012), 137 (6), 064318/1-064318/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A set of silver-doped lead Zintl anions, Ag@Pbn- (n = 5-12), have been studied using photoelectron velocity-map imaging spectroscopy and quantum chem. calcn. The structures of Ag@Pbn- (n = 7-9, 11) built upon a square pyramid base, hitherto not considered, were assigned. Overall agreement between the exptl. and calcd. photoelectron spectra as well as vertical detachment energies allows for structural evolution to be established. The silver atom prefers to stay outside in the n ≤ 6 clusters and intends to be encapsulated by the lead atoms in n > 6. A stable endohedral cage with bicapped square antiprism structure is formed at n = 10, the endohedral structure of which persists for the larger clusters. Esp., these Ag@Pbn- anions have been found to undergo a transition between square pyramid and pentagonal pyramid mol. structures at n = 11. (c) 2012 American Institute of Physics.
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636Rajesh, C.; Majumder, C. Structure and electronic properties of PbnM (M = C, Al, In, Mg, Sr, Ba, and Pb; n = 8, 10, 12, and 14) clusters: Theoretical investigations based on first principles calculations. J. Chem. Phys. 2008, 128, 024308, DOI: 10.1063/1.2814166636https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosVOjtg%253D%253D&md5=283dda4862536087a25c9ea16c4f4df7Structure and electronic properties of PbnM (M = C, Al, In, Mg, Sr, Ba, and Pb; n = 8, 10, 12, and 14) clusters: Theoretical investigations based on first principles calculationsRajesh, Chinagandham; Majumder, ChiranjibJournal of Chemical Physics (2008), 128 (2), 024308/1-024308/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A systematic theor. study of the PbnM (M=C, Al, In, Mg, Sr, Ba, and Pb; n=8, 10, 12, and 14) clusters have been investigated to explore the effect of impurity atoms on the structure and electronic properties of lead clusters. The calcns. were carried out using the d. functional theory with generalized gradient approxn. for exchange-correlation potential. Extensive search based on large nos. of initial configurations has been carried out to locate the stable isomers of PbnM clusters. The results revealed that the location of the impurity atom depends on the nature of interaction between the impurity atom and the host cluster and the size of the impurity atom. Whereas, the impurity atoms smaller than Pb favor to occupy the endohedral position, the larger atoms form exohedral capping of the host cluster. The stability of these clusters has been analyzed based on the av. binding energy, interaction energy of the impurity atoms, and the energy gap between the highest occupied and lowest unoccupied energy levels (HLG). Based on the energetics, it is found that p-p interaction dominates over the s-p interaction and smaller size atoms interact more strongly. The stability anal. of these clusters suggests that, while the substitution of Pb by C or Al enhances the stability of the Pbn clusters, Mg lowers the stability. Further investigations of the stability of PbnM clusters reveal that the interplay between the at. and electronic structure is crucial to understand the stability of these clusters. The energy gap anal. reveals that, while the substitution of Mg atom widens the HLG, all other elements reduce the gap of the PbnM clusters. (c) 2008 American Institute of Physics.
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637Chen, D.-L.; Tian, W. Q.; Sun, C.-C. First-principles studies of AlPbn and AlPbn+ clusters (n = 1–12): Search for Al-doped clusters with large stabilities. Phys. Rev. A: At., Mol., Opt. Phys. 2007, 75, 013201, DOI: 10.1103/PhysRevA.75.013201637https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXitlWitbc%253D&md5=7f87d27f5339420a6eab681b99770378First-principles studies of AlPbn and AlPbn+ clusters (n = 1-12): search for Al-doped clusters with large stabilitiesChen, De-Li; Tian, Wei Quan; Sun, Chia-ChungPhysical Review A: Atomic, Molecular, and Optical Physics (2007), 75 (1, Pt. B), 013201/1-013201/8CODEN: PLRAAN; ISSN:1050-2947. (American Physical Society)A first-principles d. functional theory based B3LYP (Becke's hybrid three-parameter exchange functional with the LYP correlation functional) method with aug-cc-pVDZ(-PP) [Dunning's augmented correlation consistent valence double zeta with polarization function on Al and pseudopotential for Pb] basis set has been used to search the most stable structures and study the electronic properties of neutral AlPbn and cationic AlPbn+ clusters (n = 1-12). The evolution of energy gaps between the HOMO and the LUMO, binding energies, and vertical ionization potentials of these clusters have been investigated. Several cationic clusters, such as AlPb9+, AlPb10+, and AlPb12+ with enhanced stability have been identified. MO analyses reveal that the special stability of D4d AlPb10+ with 42 valence electrons may arise from the closed-shell nature of the π subsystem, which is subjected to the 2(Nπ+1)2 rule with Nπ = 1. The large nucleus-independent chem. shift (NICS) values indeed demonstrate the high stability of the cationic AlPb10+. Meanwhile, the big cavity and large NICS values of isoelectronic D4d Pb102- suggest that it can encapsulate other appropriate metal atoms successfully. As to the C3v AlPb9+ cluster, its large stability may also arise from the closed-shell nature of the π subsystem with 8 π electrons, further confirmed by the large NICS values. Addnl., the nine-atom Pb clusters Pb92-, Pb93-, and Pb94- possess strong arom. character. Esp., the D3h Pb94- cluster exhibits double spherically arom. character and the largest NICS value at the center of the cage. These pure Pb clusters with large cavities and their encapsulating clusters should be good candidates for making new cluster-assembled nanostructured materials.
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638Chen, X.; Deng, K.; Xiao, C.; Chen, J.; Ellis, D. E. Geometric and magnetic properties of the neutral MPb10 and [MPb10]2 clusters (M = Fe, Co, Ni). Comput. Theor. Chem. 2011, 971, 73– 76, DOI: 10.1016/j.comptc.2011.06.008638https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVKgsrvL&md5=b89622dcf91234058dd77246538ab62cGeometric and magnetic properties of the neutral MPb10 and [MPb10]2 clusters (M = Fe, Co, Ni)Chen, Xuan; Deng, Kaiming; Xiao, Chuanyun; Chen, Jiuhua; Ellis, D. E.Computational & Theoretical Chemistry (2011), 971 (1-3), 73-76CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The geometric properties of the MPb10 monomers and their dimers (M = Fe, Co, Ni) are studied using the d.-functional method. A lot of geometries of MPb10 have been searched. We found that the transition metal (M = Fe, Co, Ni) atom is favorable to be encapsulated into the Pb10 cage, and the structure of MPb10 with an encapsulated square antiprism is energetically favorable. Furthermore, these monomers could be assembled stable dimers and retain their structural identity. The most stable structure of the [MPb10]2 dimer is the two MPb10 monomers to be bound at the triangles facing upside down to each other. In addn., the weak interaction as well as the stability of NiPb10 cluster, suggests that NiPb10 seems better adapted for the purposes of cluster assembling. Meanwhile, the magnetic properties of these monomers and dimers are also investigated.
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639Spiekermann, A.; Hoffmann, S. D.; Fässler, T. F. The Zintl ion [Pb10]2–: A rare example of a homoatomic closo cluster. Angew. Chem., Int. Ed. 2006, 45, 3459– 3462, DOI: 10.1002/anie.200503916639https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlsVKjsLg%253D&md5=3aea6e00a5d01cde4c70ab5eafe9d5ccThe Zintl ion [Pb10]2-: a rare example of a homoatomic closo clusterSpiekermann, Annette; Hoffmann, Stephan D.; Faessler, Thomas F.Angewandte Chemie, International Edition (2006), 45 (21), 3459-3462CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The closed deltahedral homoat. cluster, [Pb10]2-, is prepd. and structurally characterized as its [K(2.2.2-crypt)]+ salt. When this empty cluster is considered together with the recently published filled cluster [Ni@Pb10]2-, a striking parallel to the fullerenes emerges: Zintl ions form polyhedral cages that can enclose a central atom without any major structural alterations.
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640Gao, Y.; Bulusu, S.; Zeng, X. C. A global search of highly stable gold-covered bimetallic clusters M@Aun (n = 8-17) Endohedral gold clusters. ChemPhysChem 2006, 7, 2275– 2278, DOI: 10.1002/cphc.200600472640https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht1OnsrjO&md5=b8902a90c6366e9afaf2d34bb6db1c82A global search of highly stable gold-covered bimetallic clusters M@Aun (n = 8-17): endohedral gold clustersGao, Yi; Bulusu, Satya; Zeng, Xiao ChengChemPhysChem (2006), 7 (11), 2275-2278CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)The lowest-energy structures were calcd. of a series of gold-based bimetallic clusters MAun (n = 8-17), all satisfying the 18-electron rule using DFT. Starting from n = 9, the hetero-metal atom (M) prefers to be entirely covered by gold atoms Aun to attain the lowest-energy structure. W@Au12, Zr@Au14, Sc@Au15, and Y@Au15 are the "magic-no." clusters, having the highest binding energy per atom and the largest HOMO-LUMO gap.
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641Rajesh, C.; Majumder, C. Energy level reordering and stability of MPb12 clusters: An interplay between geometry and electronic structure. Chem. Phys. Lett. 2006, 430, 101– 107, DOI: 10.1016/j.cplett.2006.08.117641https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVWrsrbN&md5=0785c56a5ca8992a01c26e5dcac68275Energy level reordering and stability of MPb12 clusters: An interplay between geometry and electronic structureRajesh, Chinagandham; Majumder, ChiranjibChemical Physics Letters (2006), 430 (1-3), 101-107CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)We demonstrate the influence of an impurity atom in tuning the stability of Pb13 cluster. For this purpose we have investigated the electronic and geometric structure of MPb12 (M = Pb, C, Al, Mg) clusters using the ab initio mol. dynamics simulation method. The energy gap between the highest occupied and lowest unoccupied energy levels of Pb13 and MgPb12 is estd. to be 0.95 and 2.3 eV, resp. The significant increase in the energy gap is resulted from the energy level reordering of Pb13 by the incorporation of Mg atom. Further investigations of the stability of MPb12 clusters reveal that the interplay between the at. and electronic structure is crucial to understand the stability of small size clusters.
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642Chen, X.; Deng, K.; Liu, Y.; Tang, C.; Yuan, Y.; Hu, F.; Wu, H.; Huang, D.; Tan, W.; Wang, X. The geometric and magnetic properties of the endohedral plumbaspherene M@Pb12 clusters (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Chem. Phys. Lett. 2008, 462, 275– 279, DOI: 10.1016/j.cplett.2008.07.095642https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGlu77F&md5=d0573e0a18f1e3d46c4bbb0387e6876cThe geometric and magnetic properties of the endohedral plumbaspherene M@Pb12 clusters (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni)Chen, Xuan; Deng, Kaiming; Liu, Yuzhen; Tang, Chunmei; Yuan, Yongbo; Hu, Fenglan; Wu, Haiping; Huang, Decai; Tan, Weishi; Wang, XinChemical Physics Letters (2008), 462 (4-6), 275-279CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometric and magnetic properties of the M@Pb12 clusters (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) are studied using the relativistic d.-functional method. The geometric optimization shows that the ground states of these clusters are close to the Ih structure. The magnetism calcns. demonstrate that the magnetic moments of M@Pb12 vary from 1 μB to 5 μB by doping different transition-metal atoms into Pb12 cage, therefore, they possess tunable magnetic properties and have potential utility in new nanomaterials. The electronic structure calcn. shows that the Mn@Pb12 has large energy gap and doping energy. Furthermore, of particular interesting is that its structure and energy gap remain unchanged with a strong external elec. field up to 0.1 V/Å, thus, Mn@Pb12 would be a good candidate as the building block with high magnetic moment for cluster assembly.
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643Le Guennic, B.; Autschbach, J. [Pt@Pb12]2–—A challenging system for relativistic density functional theory calculations of 195Pt and 207Pb NMR parameters. Can. J. Chem. 2011, 89, 814– 821, DOI: 10.1139/v11-054643https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXosl2ksbw%253D&md5=0e36cbedfa226b2ef8d604b67c74eb49[Pt@Pb12]2- - A challenging system for relativistic density functional theory calculations of 195Pt and 207Pb NMR parametersLe Guennic, Boris; Autschbach, JochenCanadian Journal of Chemistry (2011), 89 (7), 814-821CODEN: CJCHAG; ISSN:0008-4042. (Canadian Science Publishing)The authors report computations of NMR chem. shifts and indirect spin-spin coupling consts. (J couplings) for the [Pt@Pb12]2- superatom. The system is strongly influenced by relativistic effects. The Pt-Pb coupling const. is predicted to be neg., with its magnitude being in reasonable agreement with expt. Pt and Pb chem. shifts also agree reasonably well with expt. The Pb shielding tensor is strongly anisotropic, with a large deshielding principal component dominated by magnetic coupling between frontier orbitals of the cluster that resemble at. g orbitals. The NMR parameters are sensitive to approxns. made in the computations and require the inclusion of spin-orbit coupling in the theor. model to achieve reliable results. Computing the NMR parameters of the compact [Pt@Pb12]2- system with its many electrons proves to be a challenging test case for relativistic d. functional methods.
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644Chen, D.-L.; Tian, W. Q.; Lu, W.-C.; Sun, C.-C. Special stability of cationic MPb12+ clusters and superalkali character of neutral MPb12 clusters (M = B, Al, Ga, In, and Tl). J. Chem. Phys. 2006, 124, 154313, DOI: 10.1063/1.2189224644https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjvF2nu7o%253D&md5=40bcea38cc46e94ccef9a7e6e85ea1deSpecial stability of cationic MPb12+ clusters and superalkali character of neutral MPb12 clusters (M=B, Al, Ga, In, and Tl)Chen, De-Li; Tian, Wei Quan; Lu, Wen-Cai; Sun, Chia-ChungJournal of Chemical Physics (2006), 124 (15), 154313/1-154313/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic structures and stabilities of cationic MPb12+ clusters (M = B, Al, Ga, In, and Tl) with 50 valence electrons are investigated within d. functional theory. It is shown that, at the B3LYP/cc-pVDZ(-PP) and BPW91/cc-pVDZ(-PP) levels of theory, the structures of MPb12+ with icosahedra (Ih) symmetry are energetically favorable, and their high stabilities may arise from the closed-shell nature of the π subsystems which are subject to the 2(Nπ + 1)2 rule with Nπ = 1. In addn., the possessing of large nucleus-independent chem. shifts of the five kinds of clusters reflects the common arom. character of these clusters. From the comparison of our studies on the binding energies and the HOMO and the LUMO energy gaps, the cluster AlPb12+ has higher stability than the others and this is consistent with the recent mass-spectrometric discovery of Al-doped Pb+n clusters, in which AlPb+12 is highly abundant. The same methods are used to search for the structures of the neutral MPb12 clusters. The calcns. reveal that the most stable geometries of the BPb12 and GaPb12 clusters have Ih symmetry, the AlPb12 and InPb12 clusters have Th symmetry, and the TlPb12 cluster has C5v symmetry. Furthermore, the vertical ionization potentials of the neutral MPb12 clusters are smaller than that of some alkali atoms, indicating that the neutral MPb12 clusters possess superalkali character.
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645Witzel, B. J.; Klein, W.; Dums, J. V.; Boyko, M.; Fässler, T. F. Metallocages for metal anions: Highly charged [Co@Ge9]5– and [Ru@Sn9]6– clusters featuring spherically encapsulated Co1– and Ru2– anions. Angew. Chem., Int. Ed. 2019, 58, 12908– 12913, DOI: 10.1002/anie.201907127645https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1ait7vE&md5=d8f0c9792967ffecccaba7e64025bf4bMetallocages for Metal Anions: Highly Charged [Co@Ge9]5- and [Ru@Sn9]6- Clusters Featuring Spherically Encapsulated Co1- and Ru2- AnionsWitzel, Benedikt J. L.; Klein, Wilhelm; Dums, Jasmin V.; Boyko, Marina; Faessler, Thomas F.Angewandte Chemie, International Edition (2019), 58 (37), 12908-12913CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Endohedral clusters count as mol. models for intermetallic compds.-a class of compds. in which bonding principles are scarcely understood. Herein we report sol. cluster anions with the highest charges on a single cluster to date. The clusters reflect the close analogy between intermetalloid clusters and corresponding coordination polyhedra in intermetallic compds. We now establish Raman spectroscopy as a reliable probe to assign for the first time the presence of discrete, endohedrally filled clusters in intermetallic phases. The ternary precursor alloys with nominal compns. "K5Co1.2Ge9" and "K4Ru3Sn7" exhibit characteristic bonding modes originating from metal atoms in the center of polyhedral clusters, thus revealing that filled clusters are present in these alloys. We report also on the structural characterization of [Co@Ge9]5- (1a) and [Ru@Sn9]6- (2a) obtained from solns. of the resp. alloys.
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646Yue, C. Y.; Wang, M. F.; Yuan, Z. D.; Zhou, F. X.; Zhang, H. P.; Lei, X. W. K13CoSn17–x (x = 0.1): A new ternary phase containing cobalt centered [Sn9] cluster synthesized via high-temperature reaction. Z. Anorg. Allg. Chem. 2013, 639, 911– 917, DOI: 10.1002/zaac.201300181646https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnsFSrsrs%253D&md5=2c63bc558673f340396c7c0e1c242e43K13CoSn17-x (x = 0.1). A new ternary phase containing cobalt centered [Sn9] cluster synthesized via high-temperature reactionYue, Cheng-Yang; Wang, Ming-Feng; Yuan, Zhuang-Dong; Zhou, Fang-Xia; Zhang, Hui-Ping; Lei, Xiao-WuZeitschrift fuer Anorganische und Allgemeine Chemie (2013), 639 (6), 911-917CODEN: ZAACAB; ISSN:0044-2313. (Wiley-VCH Verlag GmbH & Co. KGaA)A new ternary potassium cobalt stannide, K13CoSn17-x (x = 0.1), was obtained by reacting the mixt. of the corresponding pure elements at high temp., and structurally characterized by single-crystal x-ray diffraction study. K13CoSn17-x (x = 0.1) crystallizes in the orthorhombic space group Pbca with a 26.2799(7), b 24.1541(6), c 29.8839(6) Å, Z = 16, 18,168 obsd. reflections with I > 2σ(I), R1 = 0.0540, wR2 = 0.1243. its structure contains isolated [CoSn9] monocapped square antiprism and [Sn4] tetrahedron in the ratio 1:2, forming a hierarchical variant of Laves phase MgZn2. the structural relation between the title compd. with MgZn2 as well as other binary stannides is also discussed.
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647Rios, D.; Gillett-Kunnath, M. M.; Taylor, J. D.; Oliver, A. G.; Sevov, S. C. Addition of a thallium vertex to empty and centered nine-atom deltahedral zintl ions of germanium and tin. Inorg. Chem. 2011, 50, 2373– 2377, DOI: 10.1021/ic102152e647https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFamsrY%253D&md5=654fc2223fe6d1e19394248a80208062Addition of a thallium vertex to empty and centered nine-atom deltahedral Zintl ions of germanium and tinRios, Daniel; Gillett-Kunnath, Miriam M.; Taylor, Jacob D.; Oliver, Allen G.; Sevov, Slavi C.Inorganic Chemistry (2011), 50 (6), 2373-2377CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Ni atoms were inserted into nine-atom deltahedral Zintl ions of E94- (E = Ge, Sn) via reactions with Ni(cod)2 (cod = cyclooctadiene), and [Ni@Sn9]3- was structurally characterized. Both the empty and the Ni-centered clusters react with TlCp (Cp = cyclopentadienyl anion) and add a Tl vertex to form the deltahedral ten-atom closo-species [E9Tl]3- and [Ni@E9Tl]3-, resp. The structures of [Ge9Tl]3- and [Ni@Sn9Tl]3- showed that, as expected, the geometry of the ten-atom clusters is that of a bicapped square antiprism where the Tl-atom occupies one of the two capping vertexes. This illustrates that centering a nine-atom cluster with a Ni atom does not change its reactivity toward TlCp. All compds. were characterized by electrospray mass spectrometry.
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648Gillett-Kunnath, M. M.; Paik, J. I.; Jensen, S. M.; Taylor, J. D.; Sevov, S. C. Metal-centered deltahedral zintl ions: Synthesis of [Ni@Sn9]4– by direct extraction from intermetallic precursors and of the vertex-fused dimer [{Ni@Sn8(μ-Ge)1/2}2]4–. Inorg. Chem. 2011, 50, 11695– 11701, DOI: 10.1021/ic2016963648https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlKksb7I&md5=5966071b03d387be4d224c68cd24a0beMetal-Centered Deltahedral Zintl Ions: Synthesis of [Ni@Sn9]4- by Direct Extraction from Intermetallic Precursors and of the Vertex-Fused Dimer [{Ni@Sn8(μ-Ge)1/2}2]4-Gillett-Kunnath, Miriam M.; Paik, Joseph I.; Jensen, Sara M.; Taylor, Jacob D.; Sevov, Slavi C.Inorganic Chemistry (2011), 50 (22), 11695-11701CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Ni-centered deltahedral Sn9 clusters with a charge of 4-, i.e., [Ni@Sn9]4-, were extd. in ethylenediamine in high yield directly from intermetallic precursors with the nominal compn. K4Sn9Ni3. The new endohedral clusters were crystd. and structurally characterized in K[K(18-crown-6)]3[Ni@Sn9]·3 benzene (1a, triclinic, space group P‾1, a 10.2754(5), b 19.5442(9), and c 20.5576(13) Å, α 73.927(3), β 79.838(4), and γ 84.389(3)°, Z = 2) and K[K(2,2,2-crypt)]3[Ni@Sn9] (1b, triclinic, space group P‾1, a 15.8028(8), b 16.21350(9), and c 20.1760(12) Å, α 98.71040(10), β 104.4690(10), and γ 118.3890(10)°, Z = 2). The alternative method of a post-synthetic insertion of a Ni atom in empty Sn9 clusters by a reaction with Ni(cod)2 predominantly produces the more-oxidized clusters with a charge of 3-, i.e., the recently reported [Ni@Sn9]3-. Nonetheless, using substoichiometric amts. of 18-crown-6 as a cation sequestering agent, the authors also were able to isolate the 4- clusters as a minor phase from such reactions. They were structurally characterized in K[K(en)][K(18-crown-6)]2[Ni@Sn9]·0.5en (2, monoclinic, space group P21/n, a 10.4153(5), b 25.6788(11), and c 20.6630(9) Å, β 102.530(2)°, Z = 2). The ability of the Ni-centered clusters to exist with both 3- and 4- charges parallels the same ability of the empty clusters and is very promising for similarly rich chem. involving electron transfer and flexible oxidn. states. The authors also report the synthesis and characterization of the endohedral heteroat. dimer [{Ni@Sn8(μ-Ge)1/2}2]4- composed of two [Ni@(Sn8Ge)]-clusters fused at the Ge-vertex. The dimer was synthesized by reacting an ethylenediamine soln. of a ternary precursor with the nominal compn. K4Ge4.5Sn4.5, which is known to produce heteroat. Ge9-xSnx clusters, with Ni(cod)2. It is isostructural with the reported [{Ni@Sn8(μ-Sn)1/2}2]4- and is structurally characterized in [K-(2,2,2-crypt)]4[{Ni@Sn8(μ-Ge)1/2}2]·2en (3, monoclinic, space group C2/c, a 30.636(2), b 16.5548(12), and c 28.872(2) Å, β 121.2140(10)°, Z = 4).
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649Benda, C. B.; Waibel, M.; Köchner, T.; Fässler, T. F. Reactivity of liquid ammonia solutions of the zintl phase K12Sn17 towards mesitylcopper (I) and phosphinegold (I) chloride. Chem. - Eur. J. 2014, 20, 16738– 16746, DOI: 10.1002/chem.201404594649https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVCiurfO&md5=1cb14830557bcca8f971742c76edaa00Reactivity of Liquid Ammonia Solutions of the Zintl Phase K12Sn17 towards Mesitylcopper(I) and Phosphinegold(I) ChlorideBenda, Christian B.; Waibel, Markus; Koechner, Tobias; Faessler, Thomas F.Chemistry - A European Journal (2014), 20 (50), 16738-16746CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)To gain more insight into the reactivity of intermetalloid clusters, the reactivity of the Zintl phase K12Sn17, which contains [Sn4]4- and [Sn9]4- cluster anions, was investigated. The reaction of K12Sn17 with gold(I) phosphine chloride yielded K7[(η2-Sn4)Au(η2-Sn4)](NH3)16 (1) and K17[(η2-Sn4)Au(η2-Sn4)]2(NH2)3(NH3)52 (2), which both contain the anion [(Sn4)Au(Sn4)]7- (1a) that consists of two [Sn4]4- tetrahedra linked through a central gold atom. Anion 1a represents the first binary Au-Sn polyanion. From this reaction, the solvate structure [K([2.2.2]crypt)]3K[Sn9](NH3)18 (3; [2.2.2]crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) was also obtained. In the analogous reaction of mesitylcopper with K12Sn17 in the presence of [18]crown-6 in liq. ammonia, crystals of the compn. [K([18]crown-6)]2[K([18]crown-6)(MesH)(NH3)][Cu@Sn9](THF) (4) were isolated ([18]crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadiene, MesH = mesitylene, THF = tetrahydrofuran) and featured a [Cu@Sn9]3- cluster. A similar reaction with [2.2.2]crypt as a sequestering agent gave crystals of [K[2.2.2]crypt][MesCuMes] (5). The cocrystn. of mesitylene in 4 and the presence of [MesCuMes]- (5a) in 5 provides strong evidence that the migration of a bare Cu atom into an Sn9 anion takes place through the release of a Mes- anion from mesitylcopper, which either migrates to another mesitylcopper to form 5a or is subsequently protonated to give MesH.
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650Esenturk, E. N.; Fettinger, J.; Eichhorn, B. The closo-Pb102– Zintl ion in the [Ni@Pb10]2– cluster. Chem. Commun. 2005, 247– 249, DOI: 10.1039/b412082e650https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjtFGgsw%253D%253D&md5=aef4a91e246f74e302926909e7998c9aThe closo-Pb102- Zintl ion in the [Ni@Pb10]2- clusterEsenturk, Emren N.; Fettinger, James; Eichhorn, BryanChemical Communications (Cambridge, United Kingdom) (2005), (2), 247-249CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The cluster [Ni@Pb10]2-, prepd. from Pb94- and Ni(COD)2, contains a new Zintl ion subunit, closo-Pb102-, centered by a Ni atom. [K(2,2,2-crypt)]2[Ni@Pb10] is monoclinic, space group C2/c, R1 = 0.0582, wR2 = 0.1645.
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651Esenturk, E. N.; Fettinger, J.; Eichhorn, B. The Pb122- and Pb102- zintl ions and the M@Pb122– and M@Pb102– cluster series where M = Ni, Pd, Pt. J. Am. Chem. Soc. 2006, 128, 9178– 9186, DOI: 10.1021/ja061842m651https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xmt12muro%253D&md5=55f19bd641f53cd65c6ecaa506d34004The Pb122- and Pb102- Zintl Ions and the M@Pb122- and M@Pb102- Cluster Series Where M = Ni, Pd, PtEsenturk, Emren N.; Fettinger, James; Eichhorn, BryanJournal of the American Chemical Society (2006), 128 (28), 9178-9186CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Ethylenediamine (en) solns. of K4Pb9 react with toluene solns. of ML4 (M = Pt, Pd, L = PPh3; M = Ni, L2 = COD) and 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (2,2,2-crypt) to give M@Pb122- cluster anions (M = Pt, Pd, Ni) as the [K(2,2,2-crypt)]+ salts in low (Ni) to good (Pt) yields. The ions have near perfect Ih point symmetry and have been characterized by X-ray diffraction, 207Pb NMR and LDI-TOF mass spectrometry studies. For M = Ni, the primary product formed is the D4d Ni@Pb102- cluster that has also been structurally characterized. The M@Pb102- clusters (M = Pd, Pt) and the new Zintl ions closo-Pb102- and closo-Pb122- were formed in the gas phase but have not been detected in soln. or the solid state. The structural trends of these series of clusters have been investigated through DFT calcns. The Ni@Pb102- cluster is dynamic on the 207Pb NMR time scale at -45 °C and 104.7 MHz. The M@Pb122- ions show unusually deshielded 207Pb NMR chem. shifts that presumably arise from σ-arom. effects assocd. with their high symmetries. In the solid state the salts form superlattices of cations and anions (e.g. the AlB2 lattice of [K(2,2,2-crypt)]2[Pt@Pb12]) and are prototypes for "assembled cluster materials".
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652Krämer, T.; Duckworth, J. C.; Ingram, M. D.; Zhou, B.; McGrady, J. E.; Goicoechea, J. M. Structural trends in ten-vertex endohedral clusters, M@E10 and the synthesis of a new member of the family, [Fe@Sn10]3–. Dalton Trans. 2013, 42, 12120– 12129, DOI: 10.1039/c3dt50643f652https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3srptlKqsg%253D%253D&md5=c56a5a4453833a663cc4c3d64ed6f6b0Structural trends in ten-vertex endohedral clusters, M@E(10) and the synthesis of a new member of the family, [Fe@Sn10]3-Kramer Tobias; Duckworth Jack C A; Ingram Matthew D; Zhou Binbin; McGrady John E; Goicoechea Jose MDalton transactions (Cambridge, England : 2003) (2013), 42 (34), 12120-9 ISSN:.The synthesis of a new endohedral ten-vertex Zintl ion cluster, [Fe@Sn10](3-), isoelectronic with [Fe@Ge10](3-), is reported. In an attempt to place this new cluster within the context of the known structural chemistry of the M@E10 family (M = transition metal, E = main group element), we have carried out a detailed electronic structure analysis of the different structural types: viz bicapped square antiprismatic ([Ni@Pb10](2-), [Zn@In10](8-)), tetra-capped trigonal prismatic ([Ni@In10](10-)) and the remarkable pentagonal prismatic [Fe@Ge10](3-) and [Co@Ge10](3-). We establish that the structural trends can be interpreted in terms of a continuum of effective electron counts at the E10 cage, ranging from electron deficient (<4n + 2) in [Ni@In10](10-) to highly electron rich (>4n + 2) in [Fe@Ge10](3-). The effective electron count differs from the total valence electron count in that it factors in the increasingly active role of the metal d electrons towards the left of the transition series. The preference for a pentagonal prismatic geometry in [Fe@Ge10](3-) emerges as a natural consequence of backbonding to the cage from four orthogonal 3d orbitals of the low-valent metal ion. Our calculations suggest that the new [Fe@Sn10](3-) cluster should also exhibit structural consequences of backbonding from the metal to the cage, albeit to a less extreme degree than in its Ge analogue. The global minimum lies on a very flat surface connecting D4d, C2v and C3v-symmetric minima, suggesting a very plastic structure that may be easily deformed by the surrounding crystal environment. If so, then this provides a new and quite distinct structural type for the M@E10 family.
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653Esenturk, E. N.; Fettinger, J.; Lam, Y. F.; Eichhorn, B. [Pt@Pb12]2–. Angew. Chem., Int. Ed. 2004, 43, 2132– 2134, DOI: 10.1002/anie.200353287653https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjsFSjsbk%253D&md5=241e54ed1d0c983af0206e7e30879b49[Pt@Pb12]2-Esenturk, Emren N.; Fettinger, James; Lam, Yiu-Fai; Eichhorn, BryanAngewandte Chemie, International Edition (2004), 43 (16), 2132-2134CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The Pt centered [Pb12]2- icosahedron was prepd. from the [Pb9]4- Zintl ion and [Pt(PPh3)4] in good yield. The anion has virtual Ih point symmetry and is a rare example of a free-standing C-free arom. inorg. cluster.
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654Wang, Y.; Wang, L.-L.; Ruan, H.-P.; Luo, B.-L.; Sang, R.-L.; Xu, L. Synthesis and characterization of the endohedral plumbaspherene [Rh@Pb12]3-. Chin. J. Struct. Chem. 2015, 34, 1253– 1258654https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVSmurfN&md5=905527c6bb9adfc34dbf89e3d59a56b8Synthesis and characterization of endohedral plumbaspherene [Rh@Pb12]3-Wang, Yi; Wang, Lu-lu; Ruan, Hua-peng; Luo, Ben-long; Sang, Rui-li; Xu, LiChinese Journal of Structural Chemistry (2015), 34 (8), 1253-1258CODEN: CJSCBE ISSN:. (Editorial Board of Chinese Journal of Structural Chemistry)The endohedral plumbaspherene cluster anion [Rh@Pb12]3- was synthesized by the reaction of K4Pb9 with Rh(PPh3)3Cl in ethylenediamine (en) soln. in the presence of 18-crown-6(1,4,7,10,13,16-hexaoxacyclooctadecane), and characterized by single-crystal x-ray diffraction and energy-dispersive X-ray (EDX) anal. The novel zintl ion cluster [Rh@Pb12]3- represents the 1st structurally characterized plumbaspherene Pb12 cluster with Ih point symmetry encapsulating a Group 9 element in a spherical tetrel deltahedron. And the discovery of [Rh@Pb12]3- also provides direct proof for previous reports on the observation of [M@Pb12]x± (clusters in mass spectrometric expts. proved by quantum-chem. calcns.). DFT computations indicate that the icosahedral cluster anion [Rh@Pb12]3- is isostructural and isoelectronic with [Ir@Sn12]3-.
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655Zhou, B.; Krämer, T.; Thompson, A. L.; McGrady, J. E.; Goicoechea, J. M. A highly distorted open-shell endohedral zintl cluster: [Mn@Pb12]3–. Inorg. Chem. 2011, 50, 8028– 8037, DOI: 10.1021/ic200329m655https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpslajtr4%253D&md5=4890727fa656219c564d36437255ac51A Highly Distorted Open-Shell Endohedral Zintl Cluster: [Mn@Pb12]3-Zhou, Binbin; Kramer, Tobias; Thompson, Amber L.; McGrady, John E.; Goicoechea, Jose M.Inorganic Chemistry (2011), 50 (17), 8028-8037CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Reaction of an ethylenediamine (en) soln. of K4Pb9 and 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) with a THF soln. of Mn3(Mes)6 (Mes = 2,4,6-trimethylphenyl) yielded the anionic cluster [Mn@Pb12]3-. This species was obsd. in the pos. and neg. ion-mode electrospray mass-spectra of the crude reaction mixt. The cryst. samples obtained from such solns. allowed the authors to confirm the compn. of the sample as [K(2,2,2-crypt)]3[Mn@Pb12]·1.5en (1). Because of numerous issues related to crystal sample quality and crystallog. disorder a high-quality crystal structure soln. could not be obtained. Despite this, however, the data collected permit the authors to draw reasonable conclusions about the charge and connectivity of the [Mn@Pb12]3- cluster anion. Crystals of 1 were further characterized by elemental anal. and EPR. D. Functional Theory (DFT) calcns. on such a system reveal a highly distorted endohedral cluster anion, consistent with the structural distortions obsd. by single crystal x-ray diffraction. The cluster anions are considerably expanded compared to the 36-electron closed-shell analog [Ni@Pb12]2- and, also, exhibit significant low-symmetry distortions from the idealized icosahedral (Ih) geometry that is characteristic of related endohedral clusters. The authors' computations indicate that there is substantial transfer of electron d. from the formally Mn(-I) center to the low-lying vacant orbitals of the [Pb12]2- cage.
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656Li, L.-J.; Pan, F.-X.; Li, F.-Y.; Chen, Z.-F.; Sun, Z.-M. Synthesis, characterization and electronic properties of an endohedral plumbaspherene [Au@Pb12]3–. Inorg. Chem. Front. 2017, 4, 1393– 1396, DOI: 10.1039/C7QI00209B656https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFCltb%252FI&md5=b789883e7745964a0d391c3760ba5c5dSynthesis, characterization and electronic properties of an endohedral plumbaspherene [Au@Pb12]3-Li, Lei-Jiao; Pan, Fu-Xing; Li, Feng-Yu; Chen, Zhong-Fang; Sun, Zhong-MingInorganic Chemistry Frontiers (2017), 4 (8), 1393-1396CODEN: ICFNAW; ISSN:2052-1553. (Royal Society of Chemistry)We report the synthesis, characterization and DFT studies of a transition-metal-encapsulated superatom compd., [K(2,2,2-crypt)]3[Au@Pb12]·2py, which adopts a distorted symmetry instead of the icosahedral structure due to the second-order Jahn-Teller effect. DFT computations revealed its chem. bonding nature and arom. character, and assigned the formal electronic structure as [Au-@Pb122-]3-.
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657Kesanli, B.; Halsig, J. E.; Zavalij, P.; Fettinger, J. C.; Lam, Y.-F.; Eichhorn, B. W. Cluster growth and fragmentation in the highly fluxional platinum derivatives of Sn94-: Synthesis, characterization, and solution dynamics of Pt2@Sn174- and Pt@Sn9H3-. J. Am. Chem. Soc. 2007, 129, 4567– 4574, DOI: 10.1021/ja065764e657https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXjt1ymsbg%253D&md5=db77f00682cab473027c949c207b3a0eCluster Growth and Fragmentation in the Highly Fluxional Platinum Derivatives of Sn94-: Synthesis, Characterization, and Solution Dynamics of Pt2@Sn174- and Pt@Sn9H3-Kesanli, Banu; Halsig, Jordan E.; Zavalij, Peter; Fettinger, James C.; Lam, Yiu-Fai; Eichhorn, Bryan W.Journal of the American Chemical Society (2007), 129 (15), 4567-4574CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Sn94- reacts with Pt(PPh3)4 in ethylenediamine/toluene solvent mixts. in the presence of 2,2,2-cryptand to give four different complexes: Rudolph's complex of proposed formula [Sn9Pt(PPh3)x]4- (2), the previously reported [Pt@Sn9Pt(PPh3)]2- ion (3), and the title complexes Pt2@Sn174- (4) and Pt@Sn9H3- (5). The use of Pt(norbornene)3 instead of Pt(PPh3)4 gives complex 4 exclusively. The structure of 4 contains two Pt atoms centered in a capsule-shaped Sn17 cage. The complex is highly dynamic in soln. showing single, mutually coupled 119Sn and 195Pt NMR resonances indicative of an intramol. liq.-like dynamic exchange process. Complex 5 was characterized by selectively decoupled 1H, 119Sn, and 195Pt NMR expts. and shows similar liq.-like fluxionality. The H atom scrambles across the cage showing small couplings to both Sn and Pt atoms. Neither 3 nor 4 obeys Wades rules; they adopt structures more akin to the subunits in alloys such as PtSn4. The structural and chem. relevance to supported PtSn4 heterogeneous catalysts is discussed.
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658Jin, X.; McGrady, J. E. In Adv. Inorg. Chem.; Elsevier: Amsterdam, 2019; Vol. 73, pp 265– 304.There is no corresponding record for this reference.
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659Valden, M.; Lai, X.; Goodman, D. W. Onset of catalytic activity of gold clusters on titania with the appearance of nonmetallic properties. Science 1998, 281, 1647– 1650, DOI: 10.1126/science.281.5383.1647659https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtVSqu7w%253D&md5=18353418ee25f29fe784de789819cd8dOnset of catalytic activity of gold clusters on titania with the appearance of nonmetallic propertiesValden, M.; Lai, X.; Goodman, D. W.Science (Washington, D. C.) (1998), 281 (5383), 1647-1650CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Gold clusters ranging in diam. from 1 to 6 nm have been prepd. on single cryst. surfaces of titania in ultrahigh vacuum to investigate the unusual size dependence of the low-temp. catalytic oxidn. of carbon monoxide. Scanning tunneling microscopy/spectroscopy (STM/STS) and elevated pressure reaction kinetics measurements show that the structure sensitivity of this reaction on gold clusters supported on titania is related to a quantum size effect with respect to the thickness of the gold islands; islands with two layers of gold are most effective for catalyzing the oxidn. of carbon monoxide. These results suggest that supported clusters, in general, may have unusual catalytic properties as one dimension of the cluster becomes smaller than three at. spacings.
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660Pyykkö, P. Theoretical chemistry of gold. Angew. Chem., Int. Ed. 2004, 43, 4412– 4456, DOI: 10.1002/anie.200300624660https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2cvptFelsQ%253D%253D&md5=8df938d91d2068073332c4fbbd2cd865Theoretical chemistry of goldPyykko PekkaAngewandte Chemie (International ed. in English) (2004), 43 (34), 4412-56 ISSN:1433-7851.Gold is an element whose unique properties are strongly influenced by relativistic effects. A large body of appropriate calculations now exist and their main conclusions are summarized. The theoretical interpretation of the aurophilic attraction is discussed in detail.
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661Pyykkö, P. Theoretical chemistry of gold. II.. Inorg. Chim. Acta 2005, 358, 4113– 4130, DOI: 10.1016/j.ica.2005.06.028There is no corresponding record for this reference.
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662Schooss, D.; Weis, P.; Hampe, O.; Kappes, M. M. Determining the size-dependent structure of ligand-free gold-cluster ions. Philos. Trans. R. Soc., A 2010, 368, 1211– 1243, DOI: 10.1098/rsta.2009.0269662https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkt1SjsL8%253D&md5=5baf0ad793add602a88ee5190f52ba36Determining the size-dependent structure of ligand-free gold-cluster ionsSchooss, Detlef; Weis, Patrick; Hampe, Oliver; Kappes, Manfred M.Philosophical Transactions of the Royal Society, A: Mathematical, Physical & Engineering Sciences (2010), 368 (1915), 1211-1243CODEN: PTRMAD; ISSN:1364-503X. (Royal Society)A review. Ligand-free metal clusters can be prepd. over a wide size range, but only in comparatively small amts. Detg. their size-dependent properties has therefore required the development of exptl. methods that allow characterization of sample sizes comprising only a few thousand mass-selected particles under well-defined collision-free conditions. In this review, we describe the application of these methods to the geometric structural detn. of Au+n and Au-n with n = 3-20. Geometries were assigned by comparing exptl. data, primarily from ion-mobility spectrometry and trapped ion electron diffraction, to structural models from quantum chem. calcns.
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663Li, J.; Li, X.; Zhai, H. J.; Wang, L. S. Au20: A tetrahedral cluster. Science 2003, 299, 864– 867, DOI: 10.1126/science.1079879663https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXpt1Shsw%253D%253D&md5=7c4cfef750f80b2e5da78982bea9aab0Au20: A Tetrahedral ClusterLi, Jun; Li, Xi; Zhai, Hua-Jin; Wang, Lai-ShengScience (Washington, DC, United States) (2003), 299 (5608), 864-867CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Photoelectron spectroscopy revealed that Au20 cluster has an extremely large energy gap, which is even greater than that of C60, and an electron affinity comparable with that of C60. This observation suggests that the Au20 cluster should be highly stable and chem. inert. Using relativistic d. functional calcns., we found that Au20 possesses a tetrahedral structure, which is a fragment of the face-centered cubic lattice of bulk gold with a small structural relaxation. Au20 is thus a unique mol. with at. packing similar to that of bulk gold but with very different properties.
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664Bulusu, S.; Li, X.; Wang, L.-S.; Zeng, X. C. Evidence of hollow golden cages. Proc. Natl. Acad. Sci. U. S. A. 2006, 103, 8326– 8330, DOI: 10.1073/pnas.0600637103664https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlvFChsbc%253D&md5=8dc4f198a63c3897eda2f869e9d03b4fEvidence of hollow golden cagesBulusu, Satya; Li, Xi; Wang, Lai-Sheng; Zeng, Xiao ChengProceedings of the National Academy of Sciences of the United States of America (2006), 103 (22), 8326-8330CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The fullerenes are the first "free-standing" elemental hollow cages identified by spectroscopy expts. and synthesized in the bulk. Here, we report exptl. and theor. evidence of hollow cages consisting of pure metal atoms, Aun- (n = 16-18). To our knowledge, free-standing metal hollow cages have not been previously detected in the lab. These hollow golden cages ("bucky gold") have an av. diam. > 5.5 Å, which can easily accommodate one guest atom inside.
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665Lechtken, A.; Neiss, C.; Kappes, M. M.; Schooss, D. Structure determination of gold clusters by trapped ion electron diffraction: Au14––Au19–. Phys. Chem. Chem. Phys. 2009, 11, 4344– 4350, DOI: 10.1039/b821036e665https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXmtFCitL4%253D&md5=2fd2e3c9ae93ee8ead9d7e677c3f80aeStructure determination of gold clusters by trapped ion electron diffraction: Au14-- Au19-Lechtken, Anne; Neiss, Christian; Kappes, Manfred M.; Schooss, DetlefPhysical Chemistry Chemical Physics (2009), 11 (21), 4344-4350CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structures of mass-selected gold cluster anions Au14-- Au19- were reinvestigated using an improved low temp. trapped ion electron diffraction expt. Structures were assigned by comparing exptl. with simulated scattering functions using model structures obtained by d. functional calcns. Flat three-dimensional structures were found for Au14- and Au15-, hollow cages for Au16-- Au18- and a tetrahedral structure is found for Au19-. For several clusters in this series, our assignments differ distinctly from previous assignments.
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666Johansson, M. P.; Sundholm, D.; Vaara, J. Au32: A 24-carat golden fullerene. Angew. Chem., Int. Ed. 2004, 43, 2678– 2681, DOI: 10.1002/anie.200453986666https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXksVCgtLw%253D&md5=1979ac6021fa09d5d4057e55f9e67ec3Gold Fullerenes: Au32: a 24-carat golden fullereneJohansson, Mikael P.; Sundholm, Dage; Vaara, JuhaAngewandte Chemie, International Edition (2004), 43 (20), 2678-2681CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Relativistic quantum chem. theory suggests the existence of an interesting and surprising gold cluster. The all-gold fullerene Au32 is structurally very similar to the familiar buckminsterfullerene C60, as it is approx. the same size and hollow. Au32 is stabilized by relativistic effects and spherical aromaticity; the magnetic shielding at the center of the fullerene has the highest predicted value.
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667Gu, X.; Ji, M.; Wei, S. H.; Gong, X. G. AuN clusters (N = 32,33,34,35): Cagelike structures of pure metal atoms. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 205401, DOI: 10.1103/PhysRevB.70.205401667https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVGgsL7E&md5=c880240c23233d04ceea7d83931a5b74AuN clusters (N=32,33,34,35): cagelike structures of pure metal atomsGu, X.; Ji, M.; Wei, S. H.; Gong, X. G.Physical Review B: Condensed Matter and Materials Physics (2004), 70 (20), 205401/1-205401/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Based on the d. functional theory, we demonstrate that AuN clusters can have cagelike structures. The cage consisting of 32 Au atoms has an icosahedral symmetry with a large energy gap of 1.56 eV, suggesting high stability and chem. inertness. The calcns. show that the cagelike structure is stabilized by the relativistic effect.
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668Mingos, D. M. P. Molecular-orbital calculations on cluster compounds of gold. J. Chem. Soc., Dalton Trans. 1976, 1163– 1169, DOI: 10.1039/dt9760001163668https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE28XltFaqsb4%253D&md5=42e285886b5686a2207737a869287626Molecular-orbital calculations on cluster compounds of goldMingos, D. Michael P.Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry (1972-1999) (1976), (13), 1163-9CODEN: JCDTBI; ISSN:0300-9246.MO calcns. on [Au6(PPh3)6]2+, [Au9(PPh3)8]3+, and [Au11(PPh3)7X3] (X = SCN, I) cluster compds. showed that the overlap of the Au 6s orbitals makes a dominant contribution to the bonding. Coordination of ligands to the bare metal clusters encouraged a more favorable hybridization of the metal orbitals and resulted in stronger radial metal-metal bonding. The electronic factors responsible for the breakdown of the Polyhedral Skeletal Electron Pair rules when applied to the Au clusters were discussed.
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669Sato, T.; Lijnen, E.; Ceulemans, A. Jahn-Teller instability of icosahedral [W@Au12]-. J. Chem. Theory Comput. 2014, 10, 613– 622, DOI: 10.1021/ct400985u669https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFyrtrbF&md5=acac1b4d1c9904692a0af7e462ac0041Jahn-Teller Instability of Icosahedral [W@Au12]-Sato, Tohru; Lijnen, Erwin; Ceulemans, ArnoutJournal of Chemical Theory and Computation (2014), 10 (2), 613-622CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)The anionic state of the icosahedral W@Au12 cluster offers a rare example of a Jahn-Teller (JT) instability in an icosahedral fourfold degenerate Γ8 spinor level. The JT energy splittings of the ground Γ8 and excited sixfold degenerate Γ9 splittings in the vicinity of the degeneracy point were calcd. with relativistic d. functional theory. The results were very well explained by a first-order coupling model, based on the orbital instability of the spherical d-shell of the cluster. In addn. the pentagonal JT min. was detd. It presents a remarkable example of an auro-sandwich type compd.
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670Zhai, H. J.; Li, J.; Wang, L. S. Icosahedral gold cage clusters: M@Au12- (M = V, Nb, and Ta. J. Chem. Phys. 2004, 121, 8369– 8374, DOI: 10.1063/1.1799574670https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXptFGmt7s%253D&md5=385d6c646fc3974e1acf354a63b58398Icosahedral gold cage clusters: M@Au12- (M=V, Nb, and Ta)Zhai, Hua-Jin; Li, Jun; Wang, Lai-ShengJournal of Chemical Physics (2004), 121 (17), 8369-8374CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report the observation and characterization of a series of stable bimetallic 18-valence-electron clusters contg. a highly sym. 12-atom icosahedral Au cage with an encapsulated central heteroatom of Group VB transition metals, M@Au12- (M = V,Nb,Ta). Electronic and structural properties of these clusters were probed by anion photoelectron spectroscopy and theor. calcns. Characteristics of the M@Au-12 species include their remarkably high binding energies and relatively simple spectral features, which reflect their high symmetry and stability. The adiabatic electronic binding energies of M@Au-12 were measured to be 3.70 ± 0.03, 3.77 ± 0.03, and 3.76 ± 0.03 eV for M = V, Nb, and Ta, resp. Comparison of d.-functional calcns. with exptl. data established the highly sym. icosahedral structures for the 18-electron cluster anions, which may be promising building blocks for cluster-assembled nanomaterials in the form of stoichiometric [M@Au-12]X+ salts.
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671Autschbach, J.; Hess, B. A.; Johansson, M. P.; Neugebauer, J.; Patzschke, M.; Pyykkö, P.; Reiher, M.; Sundholm, D. Properties of WAu12. Phys. Chem. Chem. Phys. 2004, 6, 11– 22, DOI: 10.1039/B310395A671https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXpvV2lu7s%253D&md5=f84816c775f4fa90510775909e1ce8baProperties of WAu12Autschbach, Jochen; Hess, Bernd A.; Johansson, Mikael P.; Neugebauer, Johannes; Patzschke, Michael; Pyykkoe, Pekka; Reiher, Markus; Sundholm, DagePhysical Chemistry Chemical Physics (2004), 6 (1), 11-22CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The icosahedral cluster compd. WAu12 was recently predicted by P. and N. Runeberg (2002) and exptl. prepd. in the gas phase by X. Li et al. (2002). The photoelectron spectra and electron affinity were reported; the other phys. properties remain unknown. Anticipating further exptl. studies on it, vibrational spectra, NMR chem. shifts, spin-spin coupling consts., quadrupole coupling consts., and optical spectra at the level of single and double excitations are predicted. The population anal. is nontrivial. By direct numerical integration, a charge of roughly +1 is obtained for the central W atom. The charge distribution is strongly delocalized but bonding regions are clearly seen. A considerable elec. field gradient exists at the Au nuclei. Although the radial bonds are strong, the system is quite elastic. The DFT activation energy for rotating 1 hemisphere against the other 1, at a D5h transition state, is only ∼20 kJ mol-1. The corresponding hu vibrational frequency is predicted to be slightly <30 cm-1.
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672Manninen, K.; Pyykkö, P.; Hakkinen, H. A small spherical liquid: A DFT molecular dynamics study of WAu12. Phys. Chem. Chem. Phys. 2005, 7, 2208– 2211, DOI: 10.1039/b503656a672https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvFOit7o%253D&md5=893e346c844e308a248941ad6974ccdcA small spherical liquid: A DFT molecular dynamics study of WAu12Manninen, Kirsi; Pyykkoe, Pekka; Haekkinen, HannuPhysical Chemistry Chemical Physics (2005), 7 (10), 2208-2211CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The finite-temp. dynamics of WAu12, incorporating both electronic and structural effects, is studied using a d.-functional-based Born-Oppenheimer mol. dynamics method. Mol. dynamics simulations for monomol. WAu12 suggest a surface-melting-type behavior of the angular degrees of freedom between 366 and 512 K. Thermally averaged electron d.-of-states of WAu12 are compared to the exptl. photoelectron spectra of WAu12-.
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673Johansson, M. P.; Pyykkö, P. WAu12(CO)12?. Chem. Commun. 2010, 46, 3762– 3764, DOI: 10.1039/c0cc00045k673https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmtFOjur0%253D&md5=3512c60fba71d78114879dc60e130a30WAu12(CO)12?Johansson, Mikael P.; Pyykkoe, PekkaChemical Communications (Cambridge, United Kingdom) (2010), 46 (21), 3762-3764CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Calcns. (CCSD(T) and DFT-TPSSh with relativistic effective core potentials) suggest that the previously predicted and exptl. obsd. cluster WAu12 can be covered by twelve μ1-CO mols. The symmetry remains Ih and the binding energy per carbonyl is about 100 kJ mol-1 up to the last one.
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674Wang, S. Y.; Yu, J. Z.; Mizuseki, H.; Sun, Q.; Wang, C. Y.; Kawazoe, Y. Energetics and local spin magnetic moment of single 3d, 4d impurities encapsulated in an icosahedral Au12 cage. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 70, 165413, DOI: 10.1103/PhysRevB.70.165413674https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXpsVGnsbc%253D&md5=15f08ea7cdcccd9a487a575ac5de6547Energetics and local spin magnetic moment of single 3,4d impurities encapsulated in an icosahedral Au12 cageWang, Shan-Ying; Yu, Jing-Zhi; Mizuseki, Hiroshi; Sun, Qiang; Wang, Chong-Yu; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 70 (16), 165413/1-165413/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The energetics and local spin magnetic moment of a single 3,4d impurity (Sc-Ni, Y-Pd) encapsulated in an icosahedral Au12 cage were studied theor. by using a real-space 1st-principles cluster method with generalized gradient approxn. for exchange-correlation functional. The relativistic effect is considered by scalar relativistic pseudopotentials. All doped clusters show unexpected large relative binding energies compared with icosahedral Au13 cluster. The smallest and the largest values appear at Pd and Zr, 2.186 and 7.791 eV per cluster, resp., indicating doping could stabilize the icosahedral Au12 cage and promote the formation of a new binary alloy cluster. Comparatively large magnetic moments are obsd. for 3d elements Cr, Mn, Fe, Co, and Ni (2.265, 3.512, 3.064, 1.947, and 0.943 μB), and 4d elements Tc, Ru, and Rh (0.758, 1.137, and 0.893 μB). The d. of states and the relativistic effects on electronic structure are discussed.
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675Long, J.; Qiu, Y.-X.; Chen, X.-Y.; Wang, S.-G. Stable geometric and electronic structures of gold-coated nanoparticles M@Au12 (M = 5d transition metals, from Hf to Hg): Ih or Oh?. J. Phys. Chem. C 2008, 112, 12646– 12652, DOI: 10.1021/jp8033006675https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptVGjt7Y%253D&md5=532a06df4b8ee4dfeba25386cd7f8d20Stable Geometric and Electronic Structures of Gold-Coated Nanoparticles M@Au12 (M = 5d Transition Metals, from Hf to Hg): Ih or Oh?Long, Juan; Qiu, Yi-Xiang; Chen, Xian-Yang; Wang, Shu-GuangJournal of Physical Chemistry C (2008), 112 (33), 12646-12652CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The geometries and electronic structures of 5d transition metal "impurities" Hf to Hg encapsulated in icosahedral and cuboctahedral Au12 cages were investigated theor. The best d. functional results of the small test mols. Au2, AuH, AuCl, and AuCu were obtained for the geometric structures with Xα, and for the electronic energies of those frozen structures with VBP. The same procedure was then applied to the clusters. At the zeroth order regular relativistic approxn. ZORA, both at the spin-averaged scalar and at the spin-orbit-split spinor levels, the cuboctahedral clusters tend to be more stable than their icosahedral isomers, except for W@Au12. The neutral clusters have electronic closed shells only for Ih and Oh W@Au12 and for Oh Hg@Au12. The embedding energy of M into Au12 is less attractive for the later transition metal atoms M.
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676Nijamudheen, A.; Jose, D.; Datta, A. Metal encapsulation mediated planar to three dimensional structural transformation in Au-clusters: The venus flytrap effect. Comput. Theor. Chem. 2011, 966, 133– 136, DOI: 10.1016/j.comptc.2011.02.025676https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXlvVWmurY%253D&md5=4eb0dadc9d37ed2c21d22d04cdfdd2dcMetal encapsulation mediated planar to three dimensional structural transformation in Au-clusters: The venus flytrap effectNijamudheen, A.; Jose, Deepthi; Datta, AyanComputational & Theoretical Chemistry (2011), 966 (1-3), 133-136CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)DFT calcns. on small Au12 clusters reveal a side-wise folding mechanism of this planar cluster in the presence of added transition-metal atoms or ions like Cr, Mo, W, V-, Nb-, Ta-, Mn+, Tc+ and Re+. Such a process is highly exothermic and leads to the formation of an 18 electron closed shell structure. The barriers for such a conversion is small and the exptl. strategies are proposed for favorable observation of such a process.
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677Zhang, C.-H.; Cui, H.; Shen, J. The 13-atom encapsulated gold cage clusters. Chin. Phys. B 2012, 21, 103102, DOI: 10.1088/1674-1056/21/10/103102677https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlGnu7fF&md5=5d0add0f4e570e7de66f9c02278f317bThe 13-atom encapsulated gold cage clustersZhang, Chuan-Hui; Cui, Hang; Shen, JiangChinese Physics B (2012), 21 (10), 103102/1-103102/5CODEN: CPBHAJ; ISSN:1674-1056. (IOP Publishing Ltd.)The structure and the magnetic moment of transition metal encapsulated in a Au12 cage cluster have been studied by using the d. functional theory. The results show that all of the transition metal atoms (TMA) can embed into the Au12 cage and increase the stability of the clusters except Mn. Half of them have the Ih or Oh symmetry. The curves of binding energy have oscillation characteristics when the extra-nuclear electrons increase; the reason for this may be the interaction between parity changes of extra-nuclear electrons and Au atoms. The curves of HOMO-LUMO (HOMO-LUMO) gap also have oscillation characteristics when the extra-nuclear electrons increase. The binding energies of many M@Au12 clusters are much larger than that of the pure Au13 cluster, while the gaps of some of them are less than that of Au13, so maybe Cr@Au12, Nb@Au12, and W@Au12 clusters are most stable in fact. For magnetic calcns., some clusters are quenched totally, but the Au13 cluster has the largest magnetic moment of 5 μB. When the no. of extra-nuclear electrons of the encapsulated TMA is even, the magnetic moment of relevant M@Au12 cluster is even, and so are the odd ones.
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678Raggi, G.; Soto, J. R. Relativistic DFT calculations of magnetic moments of pristine and thiolated Mn@Aux (x = 6, 12). Phys. Chem. Chem. Phys. 2014, 16, 21506– 21512, DOI: 10.1039/C4CP03036B678https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVSmt7bL&md5=5e7ab82514214601fc72385490e88738Relativistic DFT calculations of magnetic moments of pristine and thiolated Mn@Aux (x = 6, 12)Raggi, G.; Soto, J. R.Physical Chemistry Chemical Physics (2014), 16 (39), 21506-21512CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The authors present the results of relativistic DFT calcns. of magnetic moments for Mn inserted into a Au ring (Mn@Au6) or a cage-like structure (Mn@Au12) both pristine and n-thiolated. Optimization was carried out to obtain different isomers always favoring the endohedral Au clusters with Mn inside. For the total magnetic moment (from electronic population anal.) verification of the jellium model was performed in each case. The magnetic moments arise largely from the doped Mn atom and thiolation can modulate its value, which is not present in the pure form. In the Mn@Au12 clusters the authors obsd. the formation of a hole in their structure; this could be a characteristic of insertion of a highly ferromagnetic dopant in some metal clusters, such as Au, and this could act as a precursor of the formation of Au magnetic nanotubes.
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679Yarzhemsky, V. G.; Izotov, A. D.; Kazaryan, M. A.; D’Yakov, Y. A. Structure of endohedral clusters Au12M. Dokl. Chem. 2015, 462, 115– 117, DOI: 10.1134/S0012500815050031679https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXps1Srurw%253D&md5=c0a4e5965821469d4c035f21b370f572Structure of endohedral clusters Au12MYarzhemsky, V. G.; Izotov, A. D.; Kazaryan, M. A.; D'yakov, Yu. A.Doklady Chemistry (2015), 462 (1), 115-117CODEN: DKCHAY; ISSN:0012-5008. (SP MAIK Nauka/Interperiodica)The present article deals with the study of formation of 13-atom clusters contg. 12 gold atoms and one 4d- or 5d-metal atom. The chem. properties of such clusters are similar to the properties of AuN (N < 14) clusters, and their structure is more compact. The structure of endohedral clusters Au12M were studied.
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680Cao, G.-J.; Schwarz, W. H. E.; Li, J. An 18-electron system containing a superheavy element: Theoretical studies of Sg@Au12. Inorg. Chem. 2015, 54, 3695– 3701, DOI: 10.1021/acs.inorgchem.5b00356680https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkvF2htrs%253D&md5=4bb3fb1e37880df8ad134f6099410897An 18-Electron System Containing a Superheavy Element: Theoretical Studies of Sg@Au12Cao, Guo-Jin; Schwarz, W. H. Eugen; Li, JunInorganic Chemistry (2015), 54 (7), 3695-3701CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)M@Au12 cage mols. (M = transition element from group 6) are interesting clusters with high-sym. structure and significant stability. As the heavier homolog of W is 106Sg, it is interesting to pinpoint whether the Sg@Au12 cluster is also stable. Geometric and electronic structures and bonding of various Sg@Au12 isomers were investigated with d. functional theory (PW91, PBE, B3LYP) and wave function theory (MP2, CCSD(T)) approaches. The lowest-energy isomer of Sg@Au12 has icosahedral symmetry with significant Sg(6d)-Au(6s) covalent-metallic interaction and is comparable to the lighter homologues (M = Mo, W), with similar binding energy, although Sg follows (as a rare case) the textbook rule "ns below (n - 1)d". The 12 6s valence electrons from Au12 and the six 7s6d ones from Sg can be viewed as an 18e system below and above the interacting Au 5d band, forming nine delocalized multicenter bond pairs with a high stability of ∼0.8 eV of bond energy per each of the 12 Sg-Au contacts. Different prescriptions (orbital, multipole-deformation, charge-partition, and X-ray-spectroscopy based ones) assign ambiguous at. charges to the centric and peripheral atoms; at. core-level energy shifts correspond to some neg. charge shift to the gold periphery, more so for Cr@Au12 than for Sg@Au12 or Au@Au12.
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681Muñoz-Castro, A. Golden endohedral main-group clusters, [E@Au12]q-: Theoretical insights into the 20-e principle. J. Phys. Chem. Lett. 2013, 4, 3363– 3366, DOI: 10.1021/jz401622m681https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVylsr%252FF&md5=5bf7159817f76da53660541b389f8a78Golden Endohedral Main-Group Clusters, [E@Au12]q-: Theoretical Insights Into the 20-e PrincipleMunoz-Castro, AlvaroJournal of Physical Chemistry Letters (2013), 4 (19), 3363-3366CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The inclusion of a transition metal (M) into an icosahedral Au12 cage ([M@Au12]q), was theor. predicted prior to its exptl. characterization on the basis of the jellium model, where the titled system is in accordance with the 18-ve principle fulfilling a 1s21p61d10 electronic configuration. In contrast, the inclusion of a p-block element (E) seems not to follow such principle, leading to an open-shell state that in turn exhibits a Jahn-Teller distortion. Hence, the icosahedral structure is no longer the more stable situation. We rationalize the electronic structure of [E@Au12],q denoting the interaction between the endohedral element and the golden cage, which rise to a 1s21p62s21d10 electronic configuration requiring 20-ve as an extension to the 18-ve principle. The 20-ve count is valid in almost the whole series, with the exception given by E = N, O, F, Cl, and Br.
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682Muñoz-Castro, A. Doping the cage. Re@Au11Pt and Ta@Au11Hg, as novel 18-ve trimetallic superatoms displaying a doped icosahedral golden cage. Phys. Chem. Chem. Phys. 2017, 19, 2459– 2465, DOI: 10.1039/C6CP07519C682https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVOksrnK&md5=a6952f07dcedbb0acc776e766bc16392Doping the cage. Re@Au11Pt and Ta@Au11Hg, as novel 18-ve trimetallic superatoms displaying a doped icosahedral golden cageMunoz-Castro, AlvaroPhysical Chemistry Chemical Physics (2017), 19 (3), 2459-2465CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Expanding the versatility of well defined clusters is a major concern in the design of building blocks towards functional nanostructures. W@Au12 is a prototypical binary bare superat. cluster involving an icosahedral symmetry, which has been discussed in the literature, precluding the proposal of several endohedral d-block and f-block element structures within a golden cage. Here we pursue the construction of related trimetallic clusters, which has been explored to a lesser extent. Our results expose the great advantages of involving heterocages in the superatom approach, unraveling Re@Au11Pt and Ta@Au11Hg as novel trimetallic candidates. Re@Au11Pt exhibits an electron-deficient element in the cage, and an endohedral atom with an extra electron. In contrast, Ta@Au11Hg is conceived as having an icosahedral cage with an extra electron, and an electron-deficient endohedral element. These new clusters follow the eighteen valence electron principle, with similar characteristics to their W@Au12 parent. This leads to stable clusters with an electronic structure formally described by the 1s21p61d10 closing shell order, showing an interesting approach to design ternary superatoms, where the variation of valence electrons occurs in both cage and endohedral sites. Moreover, the cage doping appears as a useful approach to further evaluate the formation of magnetic superatoms, and also the construction of larger clusters by fusing different icosahedral structures.
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683Stener, M.; Nardelli, A.; Fronzoni, G. Spin-orbit effects in the photoabsorption of WAu12 and MoAu12: A relativistic time dependent density functional study. J. Chem. Phys. 2008, 128, 134307, DOI: 10.1063/1.2884003683https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXksF2lu7o%253D&md5=920f898dc3fc3e78f899cff26f64fd45Spin-orbit effects in the photoabsorption of WAu12 and MoAu12: A relativistic time dependent density functional studyStener, M.; Nardelli, A.; Fronzoni, G.Journal of Chemical Physics (2008), 128 (13), 134307/1-134307/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic structure of both WAu12 and MoAu12 was calcd. at the d. functional theory (DFT) level, employing the zero order regular approxn. at the scalar relativistic level and including a spin-orbit coupling. The effect of the inclusion of the spin-orbit coupling is discussed, and the differences assigned to the nature of the encaged atom (W or Mo) are identified. Then, the excitation spectra of both clusters are calcd. at the time-dependent DFT level, also in this case at both scalar relativistic and spin-orbit levels. The inclusion of spin-orbit coupling is mandatory for an accurate description in the low energy region. At higher energy, where the d. of states is higher, the convoluted intensity can be properly described already at the scalar relativistic level. The consequences of the spin-orbit coupling on the excitation spectrum of the clusters indicate that while in WAu12 the lowest excitations are essentially shifted in energy with respect to the scalar relativistic results, in MoAu12, a dramatic splitting in many lines is actually predicted, revealing a quite different behavior of the two clusters. (c) 2008 American Institute of Physics.
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684Stener, M.; Nardelli, A.; Fronzoni, G. Theoretical study on the photoabsorption of MAu12- (M = V, Nb and Ta). Chem. Phys. Lett. 2008, 462, 358– 364, DOI: 10.1016/j.cplett.2008.08.010684https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGlu7zJ&md5=326c06eaff0332366488da4f8c11557fTheoretical study on the photoabsorption of MAu12- (M = V, Nb and Ta)Stener, M.; Nardelli, A.; Fronzoni, G.Chemical Physics Letters (2008), 462 (4-6), 358-364CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The valence photoabsorption spectra of the monoanionic closed shell icosahedral clusters M Au 12 - with M = V, Nb and Ta were calcd. with the time-dependent d. functional theory (TDDFT), employing the zero-order regular approxn. (ZORA) at both scalar relativistic and spin-orbit coupling levels. The calcd. photoabsorption spectra show interesting variations according to the nature of the encapsulated metal atom. Spin-orbit coupling plays an important role in these systems. The comparison with the neutral isoelectronic clusters WAu12 and MoAu12 suggests a curious relation along the diagonal of the periodic table.
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685Ju, W.; Yang, Z. Influence of spin-orbit coupling on electronic structures of TM@Au12 (TM = 3d, 4d, and 5d atoms). Phys. Lett. A 2012, 376, 1300– 1305, DOI: 10.1016/j.physleta.2012.02.052685https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjt1Orurw%253D&md5=4799e4126a78736cc9a9955d6583f425Influence of spin-orbit coupling on electronic structures of TM@Au12 (\\TM=3d\\, 4d, and 5d atoms)Ju, Weiwei; Yang, ZhongqinPhysics Letters A (2012), 376 (15), 1300-1305CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)Influence of spin-orbit coupling (SOC) on electronic structures of TM@Au12 (\\TM=3d\\, 4d, and 5d transition-metal atoms) is studied by using d. functional theory. The SOC can disperse much the frontier energy levels of the clusters, esp. for the clusters with TM atoms at the end of each series. The SOC generally decrease the gaps of the frontier orbitals and the spin magnetic moments due to the orbital dispersion and increase of hybridization between the TM and the host atoms, resp. Considerable orbital magnetic moments can be obtained. Our work provides imperative understanding on SOC effects in transition-metal clusters.
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686Muñoz-Castro, A.; Arratia-Perez, R. Spin-orbit effects on a gold-based superatom: A relativistic Jellium model. Phys. Chem. Chem. Phys. 2012, 14, 1408– 1411, DOI: 10.1039/C1CP22420D686https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1Kqsb3O&md5=c5b6ab837b049de08d80fcbb9b93309dSpin-orbit effects on a gold-based superatom: a relativistic Jellium modelMunoz-Castro, Alvaro; Arratia-Perez, RamiroPhysical Chemistry Chemical Physics (2012), 14 (4), 1408-1411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The inclusion of relativistic effects always brings to the scientific community great and stimulating surprises. To consider the spin-orbit term, which accounts for the interaction between the spatial and spin coordinates, requires the use of double point groups of symmetry in order to solve the Dirac equation or the two component approxn. to it, leading to total angular momenta (j) functions, at. or mol. spinors, instead of pure orbital angular momenta (l), at. or MOs. Large and small components, derived from the Dirac treatment, depict wavefunctions corresponding to fermions, electrons, which are described for the first time for a superatom case. In addn., their behavior is revisited in order to clarify the effects of the inclusion of the spin-orbit coupling into the electronic structure calcns., which can be extended to other superatoms, clusters, mols. and atoms.
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687Hossain, D.; Pittman, C. U., Jr.; Gwaltney, S. R. Structures and stabilities of the metal doped gold nano-clusters: M@Au10 (M = W, Mo, Ru, Co). J. Inorg. Organomet. Polym. Mater. 2014, 24, 241– 249, DOI: 10.1007/s10904-013-9995-6687https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhslWltLvN&md5=ddf23db079b93b16d43702b826178843Structures and Stabilities of the Metal Doped Gold Nano-Clusters: M@Au10 (M = W, Mo, Ru, Co)Hossain, Delwar; Pittman, Jr., Charles U.; Gwaltney, Steven R.Journal of Inorganic and Organometallic Polymers and Materials (2014), 24 (1), 241-249CODEN: JIOPAY; ISSN:1574-1443. (Springer)The structures and stabilities of a series of endohedral gold clusters contg. ten gold atoms M@Au10 (M = W, Mo, Ru, Co) have been detd. using d. functional theory. The gradient-cor. functional BP86, the Tao-Perdew-Staroverov-Scuseria TPSS meta-GGA functional, and the hybrid d. functionals B3LYP and PBE1PBE were employed to calc. the structures, binding energies, adiabatic ionization potentials, and adiabatic electron affinities for these clusters. The LanL2DZ effective core potentials and the corresponding valence basis sets were employed. The M@Au10 (M = W, Mo, Ru, Co) clusters have higher binding energies than an empty Au10 cluster. In addn., the large HOMO-LUMO gaps suggest that the M@Au10 (M = W, Mo, Ru, Co) clusters are all likely to be stable chem. The ionization potentials and electron affinities for these clusters are very high, and the W@Au10 and Mo@Au10 clusters have electron affinities similar to the super-halogen Al13.
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688Nhat, P. V.; Nguyen, M. T. Trends in structural, electronic and energetic properties of bimetallic vanadium-gold clusters AunV with n = 1-14. Phys. Chem. Chem. Phys. 2011, 13, 16254– 16264, DOI: 10.1039/c1cp22078k688https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFSjsbnP&md5=1a119356395376c402c8e779cd551972Trends in structural, electronic and energetic properties of bimetallic vanadium-gold clusters AunV with n = 1-14Nhat, Pham Vu; Nguyen, Minh ThoPhysical Chemistry Chemical Physics (2011), 13 (36), 16254-16264CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)A systematic quantum chem. investigation on the electronic, geometric and energetic properties of AunV clusters with n = 1-14 in both neutral and anionic states is performed using DFT-BP86/cc-pVTZ-PP calcns. Most clusters having an even no. of electrons prefer a high spin state. For odd-electron systems, a quartet state is consistently favored as the ground state up to Au8V. The larger sized Au10V, Au12V and Au14V prefer a doublet state. The clusters prefer 2D geometries up to Au8V involving a weak charge transfer. The larger systems bear 3D conformations with a more effective electron transfer from Au to V. The lowest-energy structure of a size AunV is built upon the most stable form of Aun-1V. During the growth, V is endohedrally doped in order to maximize its coordination nos. and augment the charge transfer. Energetic properties, including the binding energies, embedding energies and second-order energy differences, show that the presence of a V atom enhances considerably the thermodn. stability of odd-numbered gold clusters but reduces that of even-numbered systems. The at. shape has an apparently more important effect on the clusters stability than the electronic structure. Esp., if both at. shape and electronic condition are satisfied, the resulting cluster becomes particularly stable such as the anion Au12V-, which can thus combine with the cation Au+ to form a superat. mol. of the type [Au12V]Au. Numerous lower-lying electronic states of these clusters are very close in energy, in such a way that DFT computations cannot clearly establish their ground electronic states. Calcd. results demonstrate the existence of structural isomers with comparable energy content for several species including Au9V, Au10V, Au13V and Au14V.
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689Blades, W. H.; Reber, A. C.; Khanna, S. N.; Lopez-Sosa, L.; Calaminici, P.; Koster, A. M. Evolution of the spin magnetic moments and atomic valence of vanadium in VCux+, VAgx+, and VAux+ clusters (x = 3-14). J. Phys. Chem. A 2017, 121, 2990– 2999, DOI: 10.1021/acs.jpca.7b01030689https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXltVSqtr8%253D&md5=ec06c94f1b93c4d73ce65a232f381ed5Evolution of the Spin Magnetic Moments and Atomic Valence of Vanadium in VCux+, VAgx+, and VAux+ Clusters (x = 3-14)Blades, William H.; Reber, Arthur C.; Khanna, Shiv N.; Lopez-Sosa, Luis; Calaminici, Patrizia; Koster, Andreas M.Journal of Physical Chemistry A (2017), 121 (15), 2990-2999CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The at. structures, bonding characteristics, spin magnetic moments, and stability of VCux+, VAgx+, and VAux+ (x = 3-14) clusters were examd. using d. functional theory. Our studies indicate that the effective valence of vanadium is size-dependent and that at small sizes some of the valence electrons of vanadium are localized on vanadium, while at larger sizes the 3d orbitals of the vanadium participate in metallic bonding eventually quenching the spin magnetic moment. The electronic stability of the clusters may be understood through a split-shell model that partitions the valence electrons in either a delocalized shell or localized on the vanadium atom. A MO anal. reveals that in planar clusters the delocalization of the 3d orbital of vanadium is enhanced when surrounded by gold due to enhanced 6s-5d hybridization. Once the clusters become three-dimensional, this hybridization is reduced, and copper most readily delocalizes the vanadium's valence electrons. By understanding these unique features, greater insight is offered into the role of a host material's electronic structure in detg. the bonding characteristics and stability of localized spin magnetic moments in quantum confined systems.
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690Du, Q.; Wu, X.; Wang, P.; Wu, D.; Sai, L.; King, R. B.; Park, S. J.; Zhao, J. Structure evolution of transition metal-doped gold clusters M@Au12 (M = 3d–5d): Across the periodic table. J. Phys. Chem. C 2020, 124, 7449– 7457, DOI: 10.1021/acs.jpcc.9b11588690https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXkslWmtbk%253D&md5=f00ac7b00aef6edae3470cbcff8dc710Structure Evolution of Transition Metal-doped Gold Clusters M@Au12 (M = 3d-5d): Across the Periodic TableDu, Qiuying; Wu, Xue; Wang, Pengju; Wu, Di; Sai, Linwei; King, R. Bruce; Park, Sung Jin; Zhao, JijunJournal of Physical Chemistry C (2020), 124 (13), 7449-7457CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The comprehensive genetic algorithm (CGA) incorporated with d. functional theory (DFT) calcns. were used for a global search of the potential energy surfaces of M@Au12 (M = 3d-5d) clusters. The feasibility of the revTPSS functional was confirmed by comparison between exptl. and calcd. data such as bond lengths and vibrational frequencies of transition metal dimers. We found the ground state structures of Mo/W@Au12 clusters to be the perfect icosahedron cage. The V/Nb/Ta/Tc/Re@Au12 clusters were found to have the distorted icosahedron cages owing to Jahn-Teller effects. The lowest energy structures of Sc/Ti/Cr/Mn/Fe/Co/Ru/Rh/Ir@Au12 have the perfect or distorted magnetic cuboctahedron cages, which can be explained by a 14-electron rule in a cuboctahedral ligand field (M2+@Au122-). Y/Zr/La/Hf@Au12 clusters have the half-cage ground states, while Ni/Cu/Zn/Pt/Ag/Cd/Pd/Au/HgAu12 clusters have oblate ground states. The scalar relativistic X2C method combined with revTPSS/TZP were used to calc. the energy difference between the magnetic cuboctahedron ground state and the icosahedron isomers of Cr@Au12 using energy decompn. anal.-natural orbitals for chem. valence. The magnetic M2+@Au122- model was found to significantly enhance the d orbital interactions of transition metal atoms and reduce Pauli repulsion, resulting in magnetic cuboctahedra as the more stable structures.
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691Carey, D. M.; Muñoz-Castro, A. Au11Re: A hollow or endohedral binary cluster?. Chem. Phys. Lett. 2018, 701, 30– 33, DOI: 10.1016/j.cplett.2018.04.038There is no corresponding record for this reference.
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692Gao, Y.; Bulusu, S.; Zeng, X. C. Gold-caged metal clusters with large HOMO-LUMO gap and high electron affinty. J. Am. Chem. Soc. 2005, 127, 15680– 15681, DOI: 10.1021/ja055407o692https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFahsrrP&md5=9715de7909b49341856d003c74b64ba3Gold-Caged Metal Clusters with Large HOMO-LUMO Gap and High Electron AffinityGao, Yi; Bulusu, Satya; Zeng, Xiao ChengJournal of the American Chemical Society (2005), 127 (45), 15680-15681CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report a series of isoelectronic gold-caged metal clusters, Zr@Au14 and Hf@Au14, and anion clusters, Sc@Au14- and Y@Au14-, all having a calcd. HOMO-LUMO gap larger than the well-known tetrahedral cluster Au20, the 3D metal cluster with a very large measured HOMO-LUMO gap (1.77 eV). The clusters M@Au14 (M = Sc, Y) also exhibit a calcd. electron affinity (EA) and vertical detachment energy (VDE) not only higher than the "superhalogen" icosahedral Al13 cluster but also possibly even higher than a Cl atom which has the highest (measured) elemental EA or VDE (3.61 eV).
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693Xie, J. R. H.; Cheung, C. F.; Zhao, J. J. Tuning optical absorption and emission of sub-nanometer gold-caged metal systems M@Au14 by substitutional doping. J. Comput. Theor. Nanosci. 2006, 3, 312– 314, DOI: 10.1166/jctn.2006.3013693https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xktlalt7w%253D&md5=79e9574a5b9e9371d97b13e735276c1cTuning optical absorption and emission of sub-nanometer gold-caged metal systems M@Au14 by substitutional dopingXie, John R. H.; Cheung, Chiu Fung; Zhao, JijunJournal of Computational and Theoretical Nanoscience (2006), 3 (2), 312-314CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)Gao, Bulusu, and Zeng have recently reported a new series of isoelectronic, sub-nanometer Au-caged metal systems M@Au14 which have large energy gaps than icosahedral W@Au12 and Au32 and tetrahedral Au20. In this communication, we propose a tuning scheme, substitutional-doping, to achieve the tunable optical excitation and emission of M@Au14 over a broad wavelength region. For example, the optical absorption gaps of isoelectronic M@Au14 could be tuned from the near-IR to green by substituting the metal M with group IIIB, IVB, and VB constituents in the periodic table. Our results provide basic guidelines for further exptl. studies on the spectral properties of M@Au14 as well as for the development of M@Au14-based tunable optoelectronic devices.
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694Toprek, D.; Koteski, V. Ab initio calculations of the structure, energetics and stability of AunTi (n = 1-32) clusters. Comput. Theor. Chem. 2016, 1081, 9– 17, DOI: 10.1016/j.comptc.2016.02.005694https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xislyjurk%253D&md5=135fcc4bb8b9075604dcef09953e9768Ab initio calculations of the structure, energetics and stability of AunTi (n = 1-32) clustersToprek, Dragan; Koteski, VasilComputational & Theoretical Chemistry (2016), 1081 (), 9-17CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The stability and structure of titanium doped gold clusters (AunTi; n = 1-32) are studied by d. functional theory calcns., as implemented in the first principles code SIESTA. The exchange and correlation effects were calcd. within the generalized gradient approxn. (GGA) parametrized by Perdew, Burke and Ernzerhof (PBE). We used norm conserving Troullier-Martins pseudopotentials for the 10-electron valence configuration of Ti and 11-electron valence configuration of Au. All calcns. were spin-polarized. The global energy min. geometries of the clusters were searched for by using the simulated annealing technique. The stability of the clusters is discussed on the basis of the binding energy per atom, second-order energy difference, vertical ionization potential, vertical electron affinities, HOMO-LUMO energy gap and vibrational frequencies. Based on the simultaneous criteria of high binding energy, high band gap, high vertical ionization potential, and low electron affinity, it is found that Au4Ti and Au14Ti clusters have a higher stability and are candidates for "magic clusters", which confirms the already known results from previous works. The new result presented in this paper is that the Au20Ti and Au30Ti clusters have a higher stability too. In general, the clusters with even n are more stable than the clusters with odd n. Most of the clusters with even n are non-magnetic (total magnetic moment is zero). Our results also suggest that only the Au3Ti, Au7Ti and Au8Ti clusters have a planar structure.
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695Chen, M.-X.; Yan, X. A new magic titanium-doped gold cluster and orientation dependent cluster-cluster interaction. J. Chem. Phys. 2008, 128, 174305, DOI: 10.1063/1.2916588695https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlslGht7g%253D&md5=664495088de7f98324d9132b4feb7500A new magic titanium-doped gold cluster and orientation dependent cluster-cluster interactionChen, Ming-Xing; Yan, X. H.Journal of Chemical Physics (2008), 128 (17), 174305/1-174305/6CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The stability and structures of titanium-doped gold clusters AunTi (n = 2-16) are studied by the relativistic all-electron d.-functional calcns. The most stable structures for AunTi clusters with n = 2-7 are found to be planar. A structural transition of AunTi clusters from two-dimensional to three-dimensional geometry occurs at n = 8, while the AunTi (n = 12-16) prefer a gold cage structure with Ti atom locating at the center. Binding energy and second-order energy differences indicate that the Au14Ti has a significantly higher stability than its neighbors. A high ionization potential, low electron affinity, and large energy gap being the typical characters of a magic cluster are found for the Au14Ti. For cluster-cluster interaction between magic transition-metal-doped gold clusters, calcns. were performed for cluster dimers, in which the clusters have an icosahedral or nonicosahedral structure. Both electronic shell effect and relative orientation of clusters are responsible for the cluster-cluster interaction. (c) 2008 American Institute of Physics.
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696Zhang, M.; Zhang, H.; Zhao, L.; Li, Y.; Luo, Y. Low-energy isomer identification, structural evolution, and magnetic properties in manganese-doped gold clusters MnAun (n = 1-16). J. Phys. Chem. A 2012, 116, 1493– 1502, DOI: 10.1021/jp2094406696https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XktVGksw%253D%253D&md5=74ef42f063c07f7f06194fb1f5d033c3Low-Energy Isomer Identification, Structural Evolution, and Magnetic Properties in Manganese-Doped Gold Clusters MnAun (n = 1-16)Zhang, Meng; Zhang, Hongyu; Zhao, Lina; Li, Yan; Luo, YouhuaJournal of Physical Chemistry A (2012), 116 (6), 1493-1502CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)The size-dependent electronic, structural, and magnetic properties of Mn-doped gold clusters were systematically studied by using relativistic all-electron d. functional theory with generalized gradient approxn. A no. of new isomers were obtained for neutral MnAun (n = 1-16) clusters to probe the structural evolution. The two-dimensional (2D) to three-dimensional (3D) transition occurs in the size range n = 7-10 with manifest structure competitions. From size n = 13 to n = 16, the MnAun prefers a gold cage structure with Mn atom locating at the center. The relative stabilities of the ground-state MnAun clusters show a pronounced odd-even oscillation with the no. of Au atoms. The magnetic moments of MnAun clusters vary from 3 μB to 6 μB with the different cluster size, suggesting that nonmagnetic Aun clusters can serve as a flexible host to tailor the dopant's magnetism, which has potential applications in new nanomaterials with tunable magnetic properties.
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697Gao, Y.; Dai, X.; Kang, S.-g.; Jimenez-Cruz, C. A.; Xin, M.; Meng, Y.; Han, J.; Wang, Z.; Zhou, R. Structural and electronic properties of uranium-encapsulated Au14 cage. Sci. Rep. 2015, 4, 5862, DOI: 10.1038/srep05862There is no corresponding record for this reference.
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698Gao, Y.; Wang, B.; Lei, Y.; Teo, B. K.; Wang, Z. Actinide-embedded gold superatom models: Electronic structure, spectroscopic properties, and applications in surface-enhanced Raman scattering. Nano Res. 2016, 9, 622– 632, DOI: 10.1007/s12274-015-0942-4698https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVKgtbo%253D&md5=a46ff5e940691efb70096aee00fb430fActinide-embedded gold superatom models: Electronic structure, spectroscopic properties, and applications in surface-enhanced Raman scatteringGao, Yang; Wang, Bo; Lei, Yanyu; Teo, Boon K.; Wang, ZhigangNano Research (2016), 9 (3), 622-632CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)Actinide elements encaged in a superat. cluster can exhibit unique properties due to their hyperactive valence electrons. Herein, the electronic and spectroscopic properties of Th@Au14 are predicted and compared with that of the isoelectronic entities [Ac@Au14]- and [Pa@Au14]+ using d. functional theory. The calcn. results indicate that these clusters all adopt a closedshell superat. 18-electron configuration of the 1S21P61D10 Jellium state. The absorption spectrum of Th@Au14 can be interpreted by the Jelliumatic orbital model. In addn., calcd. spectra of pyridine-Th@Au14 complexes in the blue laser band exhibit strong peaks attributable to charge transfer (CT) from the metal to the pyridine mol. These charge-transfer bands lead to a resonant surface-enhanced Raman scattering (SERS) enhancement of ∼104. This work suggests a basis for designing and synthesizing SERS substrate materials based on actinide-embedded gold superatom models. [Figure not available: see fulltext.].
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699Gao, Y.; Liu, X.; Wang, Z. Ce@Au14: A bimetallic superatom cluster with 18-electron rule. J. Electron. Mater. 2017, 46, 3899– 3903, DOI: 10.1007/s11664-016-4934-2699https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsFKqsrfP&md5=cc27f3d5d54edce67ff97a5249fed180Ce@Au14: A Bimetallic Superatom Cluster with 18-Electron RuleGao, Yang; Liu, Xizhe; Wang, ZhigangJournal of Electronic Materials (2017), 46 (7), 3899-3903CODEN: JECMA5; ISSN:0361-5235. (Springer)Doping of gold clusters and nanoparticles has received substantial attention due to their ability to encapsulate atoms and mols. Here, the geometric and electronic properties of the cerium-encapsulated nanocage Ce@Au14 are reported using d. functional theory. Calcd. results show that its ground electronic state is a singlet state and conforms to the superat. 18-electron configuration of 1S21P61D10 jellium state, both primarily involving the bonding interaction between s- and d-shell AOs of the Ce atom and superat. orbitals of the hollow polyhedral Au14 cage. In addn., it should be noted that f electrons in rare earth atoms trend to retain their localized state, and their doping in gold clusters could easily lead to clusters with large magnetic moments. However, in the case of superatom clusters, the f-shell electrons will be the preferential arrangement at the unfilled d-shell to satisfy the superat. electron structure. Further anal. of the electronic structure also proves that the unoccupied 1F superat. orbitals mainly originate from the contribution of the 4f-shell. As a consequence, this work provides a theor. basis for the future design and synthesis of f-elements-encapsulated gold nanoclusters.
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700Gao, Y.; Jiang, W.; Xu, D.; Wang, Z. Localization-vs-delocalization of 5f orbitals in superatom systems. Adv. Theory Simul. 2018, 1, 1700038, DOI: 10.1002/adts.201700038There is no corresponding record for this reference.
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701Yong, Y.; Li, X.; Zhou, Q.; Su, X.; Li, T.; Cui, H.; Lv, S. Adsorption of gas molecules on Gd@Aun (n = 14, 15) clusters and their implication for molecule sensors. RSC Adv. 2016, 6, 26809– 26816, DOI: 10.1039/C6RA01136E701https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xjs1Git7o%253D&md5=2a68436bd3c8488e03980de2b98f1c3dAdsorption of gas molecules on Gd@Aun (n = 14, 15) clusters and their implication for molecule sensorsYong, Yongliang; Li, Xiaohong; Zhou, Qingxiao; Su, Xiangying; Li, Tongwei; Cui, Hongling; Lv, ShijieRSC Advances (2016), 6 (32), 26809-26816CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)First-principles calcns. are performed to study the adsorption of CO, NO, NO2, O2, CO2, N2, and H2O mols. on Gd@Aun (n = 14, 15) clusters. The adsorption geometries, adsorption energies, charge transfer, and electronic properties are obtained. We find that the toxic mols. (CO, NO, and NO2) are chem. adsorbed on the Gd@Aun (n = 14, 15) clusters with strong binding, and this can lead to finite charge transfer, while other common mols. (O2, CO2, N2, and H2O) are physisorbed on the Gd@Aun (n = 14, 15) clusters, expect for O2 mols. on the Gd@Au14 cluster. The electronic properties of the Gd@Aun (n = 14, 15) clusters are significantly influenced by NO and NO2 adsorption, esp. their elec. cond. Furthermore, for the Gd@Au15 cluster, it is found that the adsorption energy (Eads) of -0.498 eV for NO and -0.725 eV for NO2 corresponds to recovery times of about 7 × 10-12 and 11.8 s, resp., indicating that the Gd@Au15 cluster should be a good NO and NO2 sensor with quick response and short recovery time. However, the very strong adsorption of NO and NO2 on the Gd@Au14 cluster (Eads ≥ 1.00 eV) makes desorption difficult. Therefore, the Gd@Au15 cluster can be expected to be an excellent gas sensor for NO and NO2 detection.
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702Yadav, B. D.; Kumar, V. Gd@Au15: A magic magnetic gold cluster for cancer therapy and bioimaging. Appl. Phys. Lett. 2010, 97, 133701, DOI: 10.1063/1.3491269702https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht1Wjt7zI&md5=1c2acb9bf255aa0bec7e094fdb95859aGd@Au15: A magic magnetic gold cluster for cancer therapy and bioimagingYadav, Brahm Deo; Kumar, VijayApplied Physics Letters (2010), 97 (13), 133701/1-133701/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The authors report from ab initio calcns. a magic magnetic cage cluster of gold, Gd@Au15, obtained by doping of a Gd atom in gold clusters. It has a HOMO-LUMO gap of 1.31 eV within the generalized gradient approxn. that makes it a potential candidate for cancer therapy with an addnl. attractive feature that its large magnetic moment of 7 μB could be beneficial for magnetic resonance imaging. (c) 2010 American Institute of Physics.
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703Shinde, P. P.; Yadav, B. D.; Kumar, V. Evolution of atomic and electronic structure of magnetic Gd-doped gold clusters. J. Mater. Sci. 2012, 47, 7642– 7652, DOI: 10.1007/s10853-012-6632-7703https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xos12hsbk%253D&md5=2799b15d83a5127fcc080858b715c562Evolution of atomic and electronic structure of magnetic Gd-doped gold clustersShinde, Prashant P.; Yadav, Brahm Deo; Kumar, VijayJournal of Materials Science (2012), 47 (21), 7642-7652CODEN: JMTSAS; ISSN:0022-2461. (Springer)The evolution of at. and electronic structure of small Aun (n = 1-16, and 55) clusters doped with a Gd atom was investigated using a DFT-GGA method. Pure gold neutral clusters with n up to 15 are planar. However, with the doping of a Gd atom, the at. structure of gold clusters changes, and there is a transition from planar-like structures to three dimensional structures at n = 10. The electronic structure of Gd-doped gold clusters shows a sharp increase of the HOMO-LUMO gap for certain sizes giving rise to their magic behavior. All clusters are magnetic with large magnetic moments ranging from 6 to 8 μB primarily due to the localized 4f electrons on Gd. This makes such clusters with large HOMO-LUMO gaps magnetic superatoms. The main interaction between gold and gadolinium atoms in the clusters is due to hybridization between Au-6s and Gd-5d6s orbitals. Our results indicate the emergence of a wheel structure for Gd@Au7, a sym. cage structure at n = 15 for Gd@Au15 and n = 16 for Gd@Au16+ and Eu@Au16 corresponding to an electronic shell closing at 18 valence electrons leaving aside the f electrons on Gd while for Gd-doped Au55 corresponding to 58 valence electrons, a Au9Gd@Au46 core-shell structure is obtained in which the Gd atom connects the core of Au9 with the Au46 shell. The binding energy shows odd-even oscillations with enhancement due to Gd doping compared with pure gold clusters. Such magnetic clusters of gold could have multifunctional biol. applications in drug delivery, sensor, imaging, and cancer treatment.
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704Wang, L.-M.; Bulusu, S.; Zhai, H.-J.; Zeng, X.-C.; Wang, L.-S. Doping golden buckyballs: Cu@Au16- and Cu@Au17- cluster anions. Angew. Chem., Int. Ed. 2007, 46, 2915– 2918, DOI: 10.1002/anie.200700060704https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXkslehurs%253D&md5=7fbb9ee48874fe0f1352cc030c313000Doping golden buckyballs: Cu@Au16- and Cu@Au17- clusterWang, Lei-Ming; Bulusu, Salya; Zhai, Hua-Jin; Zeng, Xiao-Cheng; Wang, Lai-ShengAngewandte Chemie, International Edition (2007), 46 (16), 2915-2918CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Golden cage: The two smallest anionic gold cages, Au16- and Au17- are doped with a Cu atom to give the cluster anions CuAu-16 (see picture) and CuAu-17, resp. The photoelectron spectra of CuAu16- and CuAu17- suggest that the doping does not alter the structures of the parent cages. Theor. studies confirm that the Cu atom resides in the center of the gold cages, similar to the situation with endohedral fullerenes.
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705Wang, L.-M.; Bulusu, S.; Huang, W.; Pal, R.; Wang, L.-S.; Zeng, X. C. Doping the golden cage Au16- with Si, Ge, and Sn. J. Am. Chem. Soc. 2007, 129, 15136– 15137, DOI: 10.1021/ja077465a705https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlWmurbM&md5=36136d24f229cd25cfe39c72d10d14b3Doping the Golden Cage Au16- with Si, Ge, and SnWang, Lei-Ming; Bulusu, Satya; Huang, Wei; Pal, Rhitankar; Wang, Lai-Sheng; Zeng, Xiao ChengJournal of the American Chemical Society (2007), 129 (49), 15136-15137CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report a joint PES and theor. study of SiAu16-, GeAu16-, and SnAu16- clusters. We find that their global min. possess exohedral structures, which are dominated by the strong M-Au local interactions reminiscent of the MAu4 clusters. In particular, a dangling Au atom is obsd. in the low-lying isomers of SiAu16- which confirms the Au/H analogy reported earlier in Si-Au mixed clusters. The nature of the dopant-Au local interactions is a crit. factor in detg. whether an impurity atom can be used to dope the golden cages.
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706Wang, L.-M.; Pal, R.; Huang, W.; Zeng, X. C.; Wang, L.-S. Tuning the electronic properties of the golden buckyball by endohedral doping: M@Au16- (M = Ag, Zn, In). J. Chem. Phys. 2009, 130, 051101, DOI: 10.1063/1.3073884706https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1Gjuro%253D&md5=819a89725327b5fd08dcd1db08db40a0Tuning the electronic properties of the golden buckyball by endohedral doping: M@Au16- (M = Ag, Zn, In)Wang, Lei-Ming; Pal, Rhitankar; Huang, Wei; Zeng, Xiao Cheng; Wang, Lai-ShengJournal of Chemical Physics (2009), 130 (5), 051101/1-051101/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The golden Au16- cage was doped by an external atom with different valence electrons: Ag, Zn, and In. The electronic and structural properties of Ag@Au16-, Zn@Au16-, and In@Au16- were investigated by photoelectron spectroscopy and DFT-PBE method. The characteristic spectral features of Au16-, reflecting its near tetrahedral (Td) symmetry, are retained in the photoelectron spectra of MAu16-, suggesting endohedral structures with little distortion from the parent Au16- cage for the doped clusters. D. functional calcns. show that the endohedral structures of M@Au16- with Td symmetry are low-lying structures, which give simulated photoelectron spectra in good agreement with the expt. The dopant atom does not significantly perturb the electronic and at. structures of Au16-, but simply donate its valence electrons to the parent Au16- cage, resulting in a closed-shell 18-electron system for Ag@Au16-, a 19-electron system for Zn@Au16- with a large energy gap, and a 20-electron system for In@Au16-. The current work shows that the electronic properties of the golden buckyball can be systematically tuned through doping. (c) 2009 American Institute of Physics.
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707Wang, L.-M.; Bai, J.; Lechtken, A.; Huang, W.; Schooss, D.; Kappes, M. M.; Zeng, X. C.; Wang, L.-S. Magnetic doping of the golden cage cluster M@Au16- (M = Fe, Co, Ni). Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 79, 033413, DOI: 10.1103/PhysRevB.79.033413707https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlGju7g%253D&md5=43c6f6701846e4a84a92a3a9b950cd2dMagnetic doping of the golden cage cluster M@Au16- (M=Fe,Co,Ni)Wang, Lei-Ming; Bai, Jaeil; Lechtken, Anne; Huang, Wei; Schooss, Detlef; Kappes, Manfred M.; Zeng, Xiao Cheng; Wang, Lai-ShengPhysical Review B: Condensed Matter and Materials Physics (2009), 79 (3), 033413/1-033413/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Structural, electronic, and magnetic properties of the golden cage doped with a transition-metal atom, MAu16- (M=Fe,Co,Ni), are investigated using trapped ion electron diffraction, photoelectron spectroscopy, and d.-functional theory. The best agreement to expt. is obtained for endohedral M@Au16- structures but with considerable distortions to the parent Au16- cage. Fe@Au16- and Co@Au16- are found to have similar structures with C2 symmetry while a C1 structure is obtained for Ni@Au16-. The 4s electrons are obsd. to transfer to the Au16 cage, whereas atomiclike magnetism due to the unpaired 3d electrons is retained for all the doped clusters.
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708Sun, Q.; Wang, Q.; Chen, G.; Jena, P. Structure of SiAu16: Can a silicon atom be stabilized in a gold cage?. J. Chem. Phys. 2007, 127, 214706, DOI: 10.1063/1.2804872708https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsVCjt7%252FP&md5=47aa690147ac34ee381752db3e7db28bStructure of SiAu16: Can a silicon atom be stabilized in a gold cage?Sun, Qiang; Wang, Qian; Chen, Gang; Jena, PuruJournal of Chemical Physics (2007), 127 (21), 214706/1-214706/4CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Nanostructures of Au and Si as well as Au-Si hybrid structures are topics of great current interest from both scientific and technol. points of view. Recent discovery of Au clusters having fullerenelike geometries and the possibility of endohedral complexes with Si atoms inside the Au cage opens new possibilities for designing Au-Si nanostructures. Using ab initio simulated annealing method we have examd. the stability of Si-Au16 endohedral complex. Contrary to what we believed, we find that the endohedral configuration is metastable and the structure where Si atom binds to the exterior surface of the Au16 cage is the lowest energy structure. The bonding of Si to Au cluster mimics its behavior of that in bulk and liq. phase of Au. In addn., doping of Si in high concn. would cause fracture and embrittlement in gold nanostructures just as it does in the bulk phase. Covalent bonding between Au-Au and Au-Si is found to be a dominant feature in the stability of the Au-Si nanostructures. Our study provides insight that may be useful in fabricating hybrid Au-Si nanostructures for applications microelectronics, catalysis, biomedicine, and jewelry industry.
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709Walter, M.; Hakkinen, H. A hollow tetrahedral cage of hexadecagold dianion provides a robust backbone for a tuneable sub-nanometer oxidation and reduction agent via endohedral doping. Phys. Chem. Chem. Phys. 2006, 8, 5407– 5411, DOI: 10.1039/B612221C709https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht1antrfN&md5=fd5774062f6695693648fd6fee19e973A hollow tetrahedral cage of hexadecagold dianion provides a robust backbone for a tuneable sub-nanometer oxidation and reduction agent via endohedral dopingWalter, Michael; Haekkinen, HannuPhysical Chemistry Chemical Physics (2006), 8 (46), 5407-5411CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We show, via d. functional theory calcns., that dianionic Au162- cluster has a stable, hollow, Td sym. cage structure, stabilized by 18 delocalized valence electrons. The cage maintains its robust geometry, with a minor Jahn-Teller deformation, over several charge states (q = -1,0, + 1), forming spin doublet, triplet and quadruplet states according to the Hund's rules. Endohedral doping of the Au16 cage by Al or Si yields a geometrically robust, tuneable oxidn. and redn. agent. Si@Au16 is a magic species with 20 delocalized electrons. We calc. a significant binding energy for the anionic Si@Au16/O2- complex and show that the adsorbed O2 is activated to a superoxo-species, a result which is at variance with the exptl. well-documented inertness of Au16- anion towards oxygen uptake.
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710Kaydashev, V. E.; Janssens, E.; Lievens, P. Optical absorption spectra of palladium doped gold cluster cations. J. Chem. Phys. 2015, 142, 034310, DOI: 10.1063/1.4906072710https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlSmu7s%253D&md5=58d5e68ec37cef839f274354db4b40bcOptical absorption spectra of palladium doped gold cluster cationsKaydashev, Vladimir E.; Janssens, Ewald; Lievens, PeterJournal of Chemical Physics (2015), 142 (3), 034310/1-034310/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Photoabsorption spectra of gas phase Aun+ and Aun-1Pd+ (13 ≤ n ≤ 20) clusters were measured using mass spectrometric recording of wavelength dependent Xe messenger atom photodetachment at hν = 1.9-3.4 eV. Pure cationic Au clusters consisting of 15, 17, and 20 atoms have a higher integrated optical absorption cross section than the neighboring sizes. The total optical absorption cross section increases with size and Pd doping strongly reduces this cross section for all studied sizes and in particular for n = 14-17 and 20. The largest redn. of optical absorption upon Pd doping is obsd. for n = 15. (c) 2015 American Institute of Physics.
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711Neukermans, S.; Janssens, E.; Tanaka, H.; Silverans, R. E.; Lievens, P. Element- and size-dependent electron delocalization in AuNX+ clusters (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Phys. Rev. Lett. 2003, 90, 033401, DOI: 10.1103/PhysRevLett.90.033401711https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmsVansw%253D%253D&md5=9f0454442284ab8bc62ba993317b2da2Element- and Size-Dependent Electron Delocalization in AuNX+ Clusters (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni)Neukermans, S.; Janssens, E.; Tanaka, H.; Silverans, R. E.; Lievens, P.Physical Review Letters (2003), 90 (3), 033401/1-033401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We investigated the stability of gold clusters doped with open 3d-shell atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Steps, peaks, and odd-even staggering in mass abundance spectra upon photofragmentation provide evidence for enhanced stability for specific cluster sizes. The obsd. magic nos. are explained in terms of size- and dopant-dependent modifications of the effective mean-field potential within a phenomenol. shell-model approach. Element-dependent 3d electron delocalization and odd-even staggering amplitudes are related to the dopant-atom structure.
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712Bouwen, W.; Vanhoutte, F.; Despa, F.; Bouckaert, S.; Neukermans, S.; Kuhn, L. T.; Weidele, H.; Lievens, P.; Silverans, R. E. Stability effects of AunXm+ (X = Cu, Al, Y, In) clusters. Chem. Phys. Lett. 1999, 314, 227– 233, DOI: 10.1016/S0009-2614(99)01150-1712https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXnsl2ku7w%253D&md5=b9b001dc574c62395f465f58f3dd790eStability effects of AunXm+ (X=Cu, Al, Y, In) clustersBouwen, W.; Vanhoutte, F.; Despa, F.; Bouckaert, S.; Neukermans, S.; Theil Kuhn, L.; Weidele, H.; Lievens, P.; Silverans, R. E.Chemical Physics Letters (1999), 314 (3,4), 227-233CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Bimetallic AunXm clusters (X=Cu, Al, Y, In, n=1-65, m=1 and 2) were produced by a dual-target dual-laser vaporization source. Following multiphoton absorption, the stability patterns resulting from fragmentation were investigated by time-of-flight mass abundance spectrometry. AunCum+ clusters exhibit the same electronic shell effects as Aun+. Different abundance patterns are obsd. for AunAl1+ compared to AunY1+ or AunIn1+. The patterns are related to the magic nos. of the electronic shell model for clusters. The differences between the bimetallic clusters are interpreted in terms of different cluster geometries dependent on the dopant atoms nature.
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713Fa, W.; Dong, J. Structures of MAu16- (M = Ag, Li, Na, and K): How far is the endohedral doping?. J. Chem. Phys. 2008, 128, 144307, DOI: 10.1063/1.2897917713https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1czjtlGhtQ%253D%253D&md5=ea07cc63a15d02dce7467bf8daae370eStructures of MAu16 (-) (M=Ag, Li, Na, and K): how far is the endohedral doping?Fa Wei; Dong JinmingThe Journal of chemical physics (2008), 128 (14), 144307 ISSN:0021-9606.The structural and electronic properties of MAu16 (-) (M=Ag, Li, Na, and K) have been studied by the scalar relativistic all-electron density-functional calculations, in which particular attention is paid to the stability of the endohedral Au16 (-) cage doped by different dopant atoms. It is found that only the smaller atoms, such as Cu, Li, and Na, can be stably encapsulated in the Au16 (-) cage, while the addition of the larger Ag or K atom prefers to locate in the surface or outside of the cage, which is inconsistent with the previous hypothesis that the Au16 (-) cage could act as a container to hold an arbitrary heterometal atom. The stable endohedral Li@Au16 (-) and Na@Au16 (-) have a large energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital gap, indicating that they are chemically stable and may be used as potential building blocks for designing cluster-assembled materials.
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714Fa, W.; Yang, A. Detecting the lowest-energy structures of CAu16q (q = -1, 0). Phys. Lett. A 2008, 372, 6392– 6395, DOI: 10.1016/j.physleta.2008.08.069There is no corresponding record for this reference.
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715Wang, H.-Q.; Li, H.-F.; Zheng, L.-X. Doping golden cage clusters M@Au16q (M = Cr, Mn; q = 0, -1) with adjustable magnetic properties. J. Magn. Magn. Mater. 2013, 344, 79– 84, DOI: 10.1016/j.jmmm.2013.05.038715https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFWku7vO&md5=f9959f23b831eac9932c2f64068b65a8Doping golden cage clusters M@Au16q (M = Cr, Mn; q = 0, -1) with adjustable magnetic propertiesWang, Huai-Qian; Li, Hui-Fang; Zheng, Li-XinJournal of Magnetism and Magnetic Materials (2013), 344 (), g79-84CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)This work presents a systematic d. functional theory study of the structural, electronic, and magnetic properties of the golden cage doped with a transition-metal atom, M@Au16q (M = Cr, Mn; q = 0, -1). The endohedral structures are always favored. The Cr@Au16- clusters show smaller X-A energy gaps, suggesting that its geometric and electronic structures alter remarkably due to the addn. of Cr atom. However, the characteristics of the Mn@Au-16 species include their remarkably high X-A energy gaps, indicating doping by Mn atom could stabilize the hollow Au16- cage. The magnetic moment of the impurity Mn/Cr atom is slightly quenched.
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716Tang, C.; Zhu, W.; Zhang, A.; Zhang, K.; Liu, M. Endohedrally doping the gold cage Au16- with an trivalent atom B, Al, Ga, and In: Density functional studies. Comput. Theor. Chem. 2013, 1018, 1– 5, DOI: 10.1016/j.comptc.2013.05.032716https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXht1SjtrrP&md5=417546479e5e2801a28e34e00137fbccEndohedrally doping the gold cage Au-16 with an trivalent atom B, Al, Ga, and In: Density functional studiesTang, Chunmei; Zhu, Weihua; Zhang, Aimei; Zhang, Kaixiao; Liu, MingyiComputational & Theoretical Chemistry (2013), 1018 (), 1-5CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The relativistic d. functional calcns. explore that M@Au-16 (M = B, Al, Ga, and In) with M at the cage center, named as M@Au-16-center, should be the most stable. The M@Au-16-center (M = B, Al, Ga, and In) clusters have closed-shell electronic structures and large energy gaps. All of these properties are characteristic of a magic cluster and can be well understood by the jellium model. Therefore, we strongly suggest M@Au-16-center (M = B, Al, Ga, and In) are magic clusters and promising as building blocks in developing cluster-assembled materials. The energy levels and the wavefunctions of frontier orbitals explore that the HOMOs of M@Au-16-center should be partly occupied by the M atom, while the LUMOs of them should be mostly from the Au-16 bodies. The difference charge densities and the natural bonding orbital charge analyses imply the Au-M bonds have both the ionic and covalent characters. Finally, the mean static linear polarizabilities and first-order hyperpolarizabilities of M@Au-16-center are larger than those of Au-16, while their anisotropies of the polarizability tensors are smaller than those of Au-16. We rationalize the nonlinear properties by studying the low-energy optical absorption band obtained by employing time-dependent d. functional theory.
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717Li, H.-F.; Wang, H.-Q. Probing the stability of neutral and anionic transition-metal-doped golden cage nanoclusters: M@Au16 (M = Sc, Ti, V). Phys. Chem. Chem. Phys. 2014, 16, 244– 254, DOI: 10.1039/C3CP53292E717https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVGnu7fK&md5=9488742de5420115da9219bce45c281bProbing the stability of neutral and anionic transition-metal-doped golden cage nanoclusters: M@Au16 (M = Sc, Ti, V)Li, Hui-Fang; Wang, Huai-QianPhysical Chemistry Chemical Physics (2014), 16 (1), 244-254CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The golden Au16q (q = 0, -1) cage is doped systematically with an external atom of different valence electrons: Sc, Ti, and V. The structural, electronic, and magnetic properties of the doped clusters, M@Au16q (M = Sc, Ti and V; q = 0, -1) are investigated using the Saunders "Kick" (SK) global search technique combined with d.-functional theory (DFT) calcns. (SK-DFT). It is found that the closeness of the calcd. vertical/adiabatic detachment energy for Ti-doped and V-doped (3.09/3.16 eV for Ti-doped, and 3.31/3.38 eV for V-doped) is consistent with the negligible geometry change between the anionic and neutral ground state structures. The characteristics of the Sc@Au16- cluster includes its remarkably high av. binding energy and doping energy, which reflects its high stability. The different spectral features between doped M@Au16- and pure Au16- clusters indicate endohedral structures with larger distortion from the parent Au16- cage for the doped clusters. The s electrons of the Au16 cage are obsd. to transfer to Sc, Ti and V atom for doped M@Au16q clusters by natural population anal. (NPA). The magnetic moment of the impurity Sc/Ti/V atom is somewhat quenched. Furthermore, the electron localization function anal. does not reveal strong interactions. The current work shows that the electronic properties of the golden cage can be systematically tuned through doping.
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718Liu, J.-X.; Liu, Z.; Filot, I. A. W.; Su, Y.; Tranca, I.; Hensen, E. J. M. CO oxidation on Rh-doped hexadecagold clusters. Catal. Sci. Technol. 2017, 7, 75– 83, DOI: 10.1039/C6CY02277D718https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFGjtL3E&md5=440773b749632e11a01ea3e19428eb83CO oxidation on Rh-doped hexadecagold clustersLiu, Jin-Xun; Liu, Zhiling; Filot, Ivo A. W.; Su, Yaqiong; Tranca, Ionut; Hensen, Emiel J. M.Catalysis Science & Technology (2017), 7 (1), 75-83CODEN: CSTAGD; ISSN:2044-4753. (Royal Society of Chemistry)Exploring the unique catalytic properties of gold clusters assocd. with specific nano-architectures is essential for designing improved catalysts with a high mass-specific activity. We investigate the geometric and electronic structure of hexadecagold clusters in which Rh was doped. D. functional theory calcns. demonstrate that the resulting neutral and neg. charged Rh-doped Au16 clusters are stable and bind CO and O2 stronger than Au16. Consequently, activation barriers for CO oxidn. are lowered. Microkinetics simulations predict esp. neg. charged Rh-doped Au16 clusters to exhibit very high CO oxidn. activity, already at sub-ambient temp. Our findings highlight the promise of alloying gold clusters with more reactive transition metals and the importance of charge transfer from the support in heterogeneous gold systems in catalyzing CO oxidn.
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719Li, H.-F.; Wang, H.-Q. Stabilization of golden cages by encapsulation of a single transition metal atom. R. Soc. Open Sci. 2018, 5, 171019, DOI: 10.1098/rsos.171019719https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisV2rsbbK&md5=f227334e4da8312108a6c4d4ce0dc750Stabilization of golden cages by encapsulation of a single transition metal atomLi, Hui-Fang; Wang, Huai-QianRoyal Society Open Science (2018), 5 (1), 171019/1-171019/13CODEN: RSOSAV; ISSN:2054-5703. (Royal Society)Golden cage-doped nanoclusters have attracted great attention in the past decade due to their remarkable electronic, optical and catalytic properties. However, the structures of large golden cage doped with Mo and Tc are still not well known because of the challenges in global structural searches. Here, we report anionic and neutral golden cage doped with a transition metal atom MAu16 (M=Mo and Tc) using Saunders 'Kick' stochastic automation search method assocd. with d.-functional theory (DFT) calcn. (SK-DFT). The geometric structures and electronic properties of the doped clusters, MAu16q (M=Mo and Tc; q=0 and -1), are investigated by means of DFT theor. calcns. Our calcns. confirm that the 4d transition metals Mo and Tc can be stably encapsulated in the Au16- cage, forming three different configurations, i.e. endohedral cages, planar structures and exohedral derivs. The ground-state structures of endohedral cages C2v Mo@Au16- -(a) and C1 Tc@Au16- -(b) exhibit a marked stability, as judged by their high binding energy per atom (greater than 2.46 eV), doping energy (0.29 eV) as well as a large HOMO-LUMO gap (greater than 0.40 eV). The predicted photoelectron spectra should aid in future exptl. characterization of MAu16- (M=Mo and Tc).
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720Tang, C.; Zhu, W.; Zhang, K.; He, X.; Zhu, F. The density functional studies of the doped gold cages Au17M (M = Cu, Ag, Li, Na, K). Comput. Theor. Chem. 2014, 1049, 62– 66, DOI: 10.1016/j.comptc.2014.09.016720https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhs1Kgu7%252FO&md5=3012b2bf4fd28b8f95729b74e55b8517The density functional studies of the doped gold cages Au17M (M = Cu, Ag, Li, Na, K)Tang, Chunmei; Zhu, Weihua; Zhang, Kaixiao; He, Xiang; Zhu, FengComputational & Theoretical Chemistry (2014), 1049 (), 62-66CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The scalar relativistic d. functional studies are performed on the structures, stabilities, electronic properties, and polarizabilities of the Au17M (M = Cu, Ag, Li, Na, K) clusters. The smaller atom Cu(Ag, Li, and Na) can be stably encapsulated in the Au17 cage, while the larger K atom prefers to locate on the outside surface of the cage. Au17M (M = Cu, Ag, Li, Na, K) should be magic clusters and promising as building blocks in developing cluster-assembled materials. We rationalize the nonlinear properties by studying the low-energy optical absorption band obtained by employing time-dependent d. functional theory.
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721Manzoor, D.; Krishnamurty, S.; Pal, S. Endohedrally doped gold nanocages: Efficient catalysts for O2 activation and CO oxidation. Phys. Chem. Chem. Phys. 2016, 18, 7068– 7074, DOI: 10.1039/C5CP05624A721https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvVygtrzN&md5=7ecb882a5f1195bc5111376c424a0765Endohedrally doped gold nanocages: efficient catalysts for O2 activation and CO oxidationManzoor, Dar; Krishnamurty, Sailaja; Pal, SouravPhysical Chemistry Chemical Physics (2016), 18 (10), 7068-7074CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Gold nanocages are the most attractive catalytic materials as all the atoms in the cage type clusters reside on the surface, making them available for chemisorption by reacting mols. Due to a hollow space at the center, their chem. and catalytic properties can be tuned effectively and easily by endohedral doping. While a significant exptl. and theor. understanding is currently available on the structural and electronic properties of doped gold cages, very little information is available on their reactivity and catalytic behavior. In the present work, with the help of d. functional theory calcns. we demonstrate that endohedral doping leads to a notable increase in the binding energy of mol. oxygen on the gold nanocages. The enhancement in the O2 binding energy on the doped gold cages is also confirmed by a significant decrease in the Au-O and an increase in the O-O bond lengths, corroborated by a red shift (∼250 cm-1) in the O-O stretching frequency as compared to the pristine cage. Furthermore, interestingly, the doped gold cages show very low activation barriers for the environmentally important CO oxidn. reaction as compared to the pristine gold cage. Importantly, the decrease in the barrier height is comparatively greater for the rate limiting step of O-O-C-O intermediate formation and as a result the CO oxidn. is expected to be more facile on the doped gold cages. Thus, the current study highlights the role of heteroatom doping in imparting new chem. and catalytic properties to gold cages and is expected to spur further research in the design of efficient gold nanocatalysts.
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722Zorriasatein, S.; Joshi, K.; Kanhere, D. G. Electronic and structural investigations of gold clusters doped with copper: Aun-1Cu- (n = 13-19). J. Chem. Phys. 2008, 128, 184314, DOI: 10.1063/1.2913153722https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtVCrtrk%253D&md5=46c7b123b4798b7c7535299b632b5bd4Electronic and structural investigations of gold clusters doped with copper: Aun-1Cu- (n=13-19)Zorriasatein, Shahab; Joshi, Kavita; Kanhere, D. G.Journal of Chemical Physics (2008), 128 (18), 184314/1-184314/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We have obtained the ground state and the equil. geometries of Aun- and Aun-1Cu- in the size range of n=13-19. We have used first principles d. functional theory within plane wave and Gaussian basis set methods. For each of the cluster we have obtained at least 100 distinct isomers. The anions of gold clusters undergo two structural transformations, the first one from flat cage to hollow cage and the second one from hollow cage to pyramidal structure. The Cu doped clusters do not show any flat cage structures as the ground state. The copper doped systems evolve from a general 3D structure to hollow cage with Cu trapped inside the cage at n=16 and then to pyramidal structure at n=19. The introduction of copper atom enhances the binding energy per atom as compared to gold cluster anions. (c) 2008 American Institute of Physics.
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723Jayasekharan, T.; Ghanty, T. K. Endohedrally doped golden fullerenes X@Au32 (X = Li+, Na+, K+, Rb+, Cs+). J. Phys. Chem. C 2010, 114, 8787– 8793, DOI: 10.1021/jp100705z723https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXltVynt7Y%253D&md5=0c357095a3b0fa0e5a877d81341ad5a0Endohedrally Doped Golden Fullerenes [X@Au32] (X = Li+, Na+, K+, Rb+, Cs+)Jayasekharan, T.; Ghanty, T. K.Journal of Physical Chemistry C (2010), 114 (19), 8787-8793CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structure, stability, energy partition anal., and charge redistribution of endohedral complexes formed between Au32 cluster with alkali metal cations, such as Li+, Na+, K+, Rb+, and Cs+, have been investigated using the d. functional theory method. All alkali metal cations can be stably encapsulated in both the Ih and the Cs symmetry structural forms [Ih-(X@Au32)+ and Cs-(X@Au32)+]. Smaller cations are found to be more stable in the Cs symmetry structure. A higher charge-transfer characteristic is noted when the Au32 cage is encapsulated with smaller-sized alkali ions than larger-sized ions in both the structures. Vibrational frequency calcn. data show imaginary frequency values for Li+ and Na+ ions in the Ih-(X@Au32) system, which indicates the free movements of these ions in the cage, whereas all dopant ions show pos. IR frequency values for Cs-(X@Au32), suggesting the existence of weak bonding between dopants and the cage. The anal. of structural, energetic, and charge-transfer data indicates that the K+, Rb+, and Cs+ dopant ions occupy the central position of the Au32 cage and retain the Ih sym. structure of the Au32 cluster, whereas the smaller-sized Li+ and Na+ occupy the off-center site and are more stable in Cs-(X@Au32). Morokuma-type energy decompn. anal. data indicate a significantly higher Pauli repulsion energy with Li+ and Na+ dopants in the Cs-(X@Au32) structure than in the Ih-(X@Au32) structure; however, for other dopant ions, this interaction is almost the same for both Ih and Cs structures. A similar trend is reflected in the variation in the orbital interaction energy term, which is considerably higher for Li+ and Na+ ions in the Cs structure and is almost the same for other ions in the Cs and Ih structures. From the charge-transfer data, a halogen-like behavior of Au32 is noted when the cluster is doped with the Cs+ ion, which is rather unusual. Thus, encapsulation of larger cations, such as K+, Rb+, and Cs+, into the Au32 fullerene may be one of the possible ways of detecting the elusive Ih structure of Au32 by mass spectrometry.
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724Manna, D.; Jayasekharan, T.; Ghanty, T. K. Structure and stability of Zn, Cd, and Hg atom doped golden fullerene (Au32). J. Phys. Chem. C 2013, 117, 18777– 18788, DOI: 10.1021/jp407089u724https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXht1CqtbnO&md5=52dd19cdffa6812c853035265b934e2eStructure and Stability of Zn, Cd, and Hg Atom Doped Golden Fullerene (Au32)Manna, Debashree; Jayasekharan, T.; Ghanty, Tapan K.Journal of Physical Chemistry C (2013), 117 (36), 18777-18788CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Structures and properties of various complexes formed between the "golden fullerene", Au32, and group IIB atoms such as Zn, Cd, and Hg were investigated using d. functional theory. Binding energy values indicate that the group IIB atoms can form stable clusters in most of the different isomeric forms of the Au32 cage. The HOMO-LUMO gap of the Au32 cage remains almost the same even after doping of Zn, Cd, and Hg atoms for high symmetry clusters, while it decreases for the low symmetry isomers. The highest stable isomer for the Hg-doped Au32 cluster is found to be assocd. with Ih symmetry with a large energy difference from the other low symmetry isomers, using generalized gradient approxn. (GGA) type functionals. However, for the Zn and Cd encapsulated Au32 clusters, the highest stable structures are of Cs[1] and C5v symmetry, resp., along with one low symmetry isomer for each of them, having energy very close to the resp. most stable isomer. Nevertheless, depending on the energy d. functional, the relative energy orderings for the various isomers are found to be modified strongly. In fact, the meta-GGA TPSS functional predicts low symmetry compact isomers to be more stable for all the metal atom doped Au32 clusters. Moreover, low symmetry compact isomers are found to be more stable with the dispersion-cor. GGA type PBE functional for the Zn- and Cd-doped cluster, in agreement with the TPSS results; however, the same dispersion correction fails to reproduce the TPSS results for the Hg-doped Au32 system. Structural data, energetic parameters, and spectral anal. point toward the possible exptl. observation of group IIB atom doped golden fullerene, which in turn might help to understand the nature of interactions between the metal atom and the Au32 cage. Furthermore, exptl. investigations would likely confirm the predictive ability of the different functionals used in this work.
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725Kumar, V. Coating of a layer of Au on Al13: The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 79, 085423, DOI: 10.1103/PhysRevB.79.085423725https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXisFKgtrg%253D&md5=4738bffa8ce1a48687d3cfa3d80677bcCoating of a layer of Au on Al13: The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculationsKumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2009), 79 (8), 085423/1-085423/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We report results of ab initio pseudopotential calcns. on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally sym. endohedral Al@Al12Au20- and empty cage Al12Au202- compd. fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compd. fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, resp., which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.
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726Wang, Q.; Sun, Q.; Jena, P. Stabilizing a 22 karat nanogolden cage. J. Chem. Phys. 2009, 131, 204501, DOI: 10.1063/1.3266562726https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsV2itLfL&md5=52cd2e84094b32585bf1a1583b34df7dStabilizing a 22 karat nanogolden cageWang, Q.; Sun, Q.; Jena, P.Journal of Chemical Physics (2009), 131 (20), 204501/1-204501/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Since the discovery of C60 fullerene, considerable efforts have been devoted to find other elements with similar hollow cage structures. However, search for hollow metallic cages with a diam. similar to that of C60 fullerene has been elusive. We describe a procedure for the rational design of metallic cages by suitably choosing their size, compn., and charge state. A 22 karat nanogolden cage with a diam. of about 8.5 Å and consisting of 12 Al and 20 Au atoms is found to be metastable, which can be stabilized by embedding a Mn4 cluster. In contrast to bulk Mn, which is antiferromagnetic, and isolated Mn4 cluster, which is ferromagnetic with a giant magnetic moment of 20μB, the Mn4@Al12Au20 endohedral complex exhibits magnetic bistability with 0μB and 14μB configurations being energetically nearly degenerate. These results, based on d. functional theory, open the door to design a novel class of endohedral complexes with possible applications. (c) 2009 American Institute of Physics.
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727Tian, D.; Zhang, H.; Zhao, J. Structure and structural evolution of Agn (n = 3-22) clusters using a genetic algorithm and density functional theory method. Solid State Commun. 2007, 144, 174– 179, DOI: 10.1016/j.ssc.2007.05.020727https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtVOkur%252FE&md5=79f56f45edd0df4a7ee1e9cff444d03fStructure and structural evolution of Agn (n = 3-22) clusters using a genetic algorithm and density functional theory methodTian, Dongxu; Zhang, Hualei; Zhao, JijunSolid State Communications (2007), 144 (3-4), 174-179CODEN: SSCOA4; ISSN:0038-1098. (Elsevier Ltd.)Using a genetic algorithm followed by local optimization with d. functional theory, the lowest-energy structures of Agn clusters in a size range of n = 3-22 were studied. The Agn (n = 9-16) clusters prefer compact structures of flat shape, while the Agn (n = 19, 21, 22) clusters adopt amorphous packing based on a 13-atom icosahedral core. For Ag16, two competitive candidates for the lowest-energy structures, namely a hollow-cage structure and close-packed structures of flat shape, were found. Two competing candidates were found for Ag17 and Ag18: hollow-cage structures vs. icosahedron-based compact structures. The lowest-energy structure of Ag20 is a highly sym. tetrahedron with Td symmetry. These results are significantly different from those predicted in earlier works using empirical methods. The ionization potentials and electron affinities for the lowest-energy structures of Agn (n = 3-22) clusters were computed and compared with exptl. values.
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728Weis, P.; Bierweiler, T.; Gilb, S.; Kappes, M. M. Structures of small silver cluster cations (Agn+, n < 12): Ion mobility measurements versus density functional and MP2 calculations. Chem. Phys. Lett. 2002, 355, 355– 364, DOI: 10.1016/S0009-2614(02)00277-4728https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjslWisrs%253D&md5=423c7bec17dc4c0893c84848a31783cbStructures of small silver cluster cations (Agn+, n < 12): ion mobility measurements versus density functional and MP2 calculationsWeis, Patrick; Bierweiler, Thomas; Gilb, Stefan; Kappes, Manfred M.Chemical Physics Letters (2002), 355 (3,4), 355-364CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)We have performed ion mobility measurements on silver cluster cations Agn+ generated by pulsed laser vaporization. For clusters with n < 12, exptl. cross-sections are compared with theor. results from d. functional and MP2 (Moller-Plesset) calcns. This comparison allows structural assignment. We find that room temp. silver cluster cations have planar structures for n = 3-4. Starting at n = 5 they form three dimensional structures. The structures are compared with predictions by Bonacic-Koutecky et al. and the resp. results obtained in a previous study for gold clusters.
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729Janssens, E.; Neukermans, S.; Nguyen, H. M. T.; Nguyen, M. T.; Lievens, P. Quenching of the magnetic moment of a transition metal dopant in silver clusters. Phys. Rev. Lett. 2005, 94, 113401, DOI: 10.1103/PhysRevLett.94.113401729https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXisl2lt7c%253D&md5=2a7ed0a47013d3de47eafc28019156beQuenching of the Magnetic Moment of a Transition Metal Dopant in Silver ClustersJanssens, E.; Neukermans, S.; Nguyen, H. M. T.; Nguyen, M. T.; Lievens, P.Physical Review Letters (2005), 94 (11), 113401/1-113401/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Single magnetic atoms embedded in a nonmagnetic host exhibit the Kondo effect in the bulk limit, while in very small mols. the magnetic atom is hardly affected by the matrix. In a combined theor. (d. functional theory) and exptl. (photofragmentation and mass spectrometry) study the authors consider the intermediate case of nanometer sized transition-metal-doped silver clusters. In particular, the authors provide exptl. evidence for enhanced stability of the cobalt-doped silver cluster Ag10Co+ and show theor. that it has a sym. endohedral geometry with a closed 18-electron singlet electronic shell structure. This implies that the magnetic moment on the cobalt atom is quenched.
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730Janssens, E.; Neukermans, S.; Wang, X.; Veldeman, N.; Silverans, R. E.; Lievens, P. Stability patterns of transition metal doped silver clusters: Dopant- and size-dependent electron delocalization. Eur. Phys. J. D 2005, 34, 23– 27, DOI: 10.1140/epjd/e2005-00106-9730https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtFOru7w%253D&md5=1192a7a41d56f1e8efa301aeb07ebaf0Stability patterns of transition metal doped silver clusters: Dopant- and size-dependent electron delocalizationJanssens, E.; Neukermans, S.; Wang, X.; Veldeman, N.; Silverans, R. E.; Lievens, P.European Physical Journal D: Atomic, Molecular and Optical Physics (2005), 34 (1-3), 23-27CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)The stability of cationic silver clusters doped with a 3d transition metal atom (Sc, Ti, V, Cr, Mn, Ni, Cu) is investigated by mass spectrometric anal. of fragments resulting from high fluence irradn. of a cluster beam. The mass spectra show enhanced stabilities that correspond to closed shells of valence electrons. Dopant- and size-dependent delocalization of 4s and 3d electrons is discussed based on spherical shell model considerations. Contrary to doped gold clusters, no evidence was found for the existence of 2D electronic shell closures.
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731Janssens, E.; Van Hoof, T.; Veldeman, N.; Neukermans, S.; Hou, M.; Lievens, P. Mass spectrometric and modeling investigations of bimetallic silver-cobalt clusters. Int. J. Mass Spectrom. 2006, 252, 38– 46, DOI: 10.1016/j.ijms.2006.01.009731https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xjsl2qsbg%253D&md5=0092473566b504355a6b5fafdc9e4b25Mass spectrometric and modeling investigations of bimetallic silver-cobalt clustersJanssens, Ewald; Van Hoof, Thibaut; Veldeman, Nele; Neukermans, Sven; Hou, Marc; Lievens, PeterInternational Journal of Mass Spectrometry (2006), 252 (1), 38-46CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)The stability of bimetallic Ag-Co clusters with <50 atoms is studied exptl. and their assocd. geometries are predicted by classical modeling. The clusters are created by laser vaporization and inert gas condensation. Their mass distribution is analyzed with time-of-flight mass spectrometry. For clusters contg. mainly Ag, strong quantum size effects related to itinerant behavior of the Ag and Co valence electrons were found. In the case of clusters contg. mainly Co, no pronounced size effects appear in the mass spectra. Photofragmentation expts. reveal that neutral Ag atom evapn. is the favorable channel, suggesting that the Ag-Co bonds are weaker than the Co-Co bonds. Consistently, and for both sets of clusters, Metropolis Monte-Carlo simulations predict these clusters to have icosahedral based structures that may depend on temp. In clusters contg. mainly Ag, Co sits at the cluster center and fragmentation proceeds by the evapn. of Ag surface atoms. In clusters contg. mainly Co, Ag atoms also locate at the periphery and are more weakly bound to the cluster than Co surface atoms.
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732Tono, K.; Terasaki, A.; Ohta, T.; Kondow, T. Photoelectron spectroscopy and density-functional calculations of silver cluster anions doped with a cobalt atom: Size dependent sp-d interaction. Chem. Phys. Lett. 2007, 449, 276– 281, DOI: 10.1016/j.cplett.2007.10.077732https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlOmt7%252FF&md5=951229d52c9b41c3071a5485b4f2b46aPhotoelectron spectroscopy and density-functional calculations of silver cluster anions doped with a cobalt atom: Size dependent sp-d interactionTono, Kensuke; Terasaki, Akira; Ohta, Toshiaki; Kondow, TamotsuChemical Physics Letters (2007), 449 (4-6), 276-281CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)Electronic structures of AgnCo- (n = 6-8) were investigated by photoelectron spectroscopy and d.-functional calcns. The local spin magnetic moments on Co were found to be 2.04, 1.48, and 0 μB for n = 6, 7, and 8, resp. A strong sp-d interaction in n = 8 allows the Co 3d orbitals to form a closed electronic shell, whereas the Co 3d shells in n = 6 and 7 remain open with finite spins under a weak sp-d interaction. The present result demonstrates significant size dependence of an sp-d interaction in a metal cluster contg. a magnetic impurity.
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733Rodriguez-Kessler, P. L.; Rodriguez-Dominguez, A. R. Structural, electronic, and magnetic properties of AgnCo (n = 1-9) clusters: A first-principles study. Comput. Theor. Chem. 2015, 1066, 55– 61, DOI: 10.1016/j.comptc.2015.05.009733https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXptFGhurw%253D&md5=7444f07941f938c6902b7d7d4f59a626Structural, electronic, and magnetic properties of AgnCo (n = 1-9) clusters: A first-principles studyRodriguez-Kessler, P. L.; Rodriguez-Dominguez, A. R.Computational & Theoretical Chemistry (2015), 1066 (), 55-61CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)Structural, electronic and magnetic properties of neutral AgnCo (n = 1 - 9) clusters are studied using first principles calcns. based on d. functional theory. For the ground state structures of the AgnCo clusters, the Co impurity occupies the highest coordinated position. The lowest energy structures for AgnCo (n≤4) clusters are planar, while from n = 5 onwards, AgnCo clusters showed an icosahedral growth except for Ag9Co, which adopts an endohedral cage structure. The stability based on the binding energy showed that AgnCo clusters are energetically favored for the high spin configuration, however, from n = 7 onwards, trends to adopt the low spin or non-magnetic configurations are obsd. Interestingly, in Ag9Co the silver host quenches the magnetic moment of the encapsulated Co atom. The magnetic orderings between the impurity and the Agn host in AgnCo clusters are discussed.
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734Zhang, M.; Gu, X.-Y.; Zhang, W.-L.; Zhao, L.-N.; He, L.-M.; Luo, Y.-H. Probing the magnetic and structural properties of the 3d, 4d, 5d impurities encapsulated in an icosahedral Ag12 cage. Phys. B 2010, 405, 642– 648, DOI: 10.1016/j.physb.2009.09.080734https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVyqt7bK&md5=49fb12ffc5f9f377e74c704dd3911ac4Probing the magnetic and structural properties of the 3d, 4d, 5d impurities encapsulated in an icosahedral Ag12 cageZhang, Meng; Gu, Xiao-Yan; Zhang, Wen-Li; Zhao, Li-Na; He, Li-Ming; Luo, You-HuaPhysica B: Condensed Matter (Amsterdam, Netherlands) (2010), 405 (2), 642-648CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)The geometries, electronic, and magnetic properties of the 3d, 4d, 5d impurities encapsulated in an icosahedral Ag12 cage have been systematically investigated by using relativistic all-electron d. functional theory with generalized gradient approxn. The general features of the properties of 3d, 4d, 5d transition-metal atoms doped Ag12 clusters are probed and compared. It is found that the most stable structure for all M@Ag12 clusters (M=3d, 4d and 5d transition-metal atoms) is the icosahedral structure with Ih symmetries, in which the transition-metal atom is located in the center of the Ag12 cage. All doped clusters show larger relative binding energies compared with pure icosahedral Ag13 cluster, indicating that doping by 3d, 4d, 5d transition-metal atoms could stabilize the Ag12 icosahedron and form a new binary alloy cluster. The calcn. of the magnetic properties demonstrates that the magnetic moments of M@Ag12 clusters vary from 0 to 4μB by doping different transition-metal atom into Ag12 icosahedron, suggesting that the transition-metal-doped Ag12 clusters could have potential utility in new nanomaterials as building blocks with tunable magnetic properties.
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735Gong, X.; Ju, W.; Li, T.; Feng, Z.; Wang, Y. Spin-orbit splitting and magnetism of icosahedral M@Ag12 clusters (M = 3d and 4d atoms). J. Cluster Sci. 2015, 26, 759– 773, DOI: 10.1007/s10876-014-0737-x735https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXovFCntro%253D&md5=b32a3757105ea351928fc7e54aa9b371Spin-orbit splitting and magnetism of icosahedral M@Ag12 clusters (M = 3d and 4d atoms)Gong, Xiaoyang; Ju, Weiwei; Li, Tongwei; Feng, Zhenjie; Wang, YangJournal of Cluster Science (2015), 26 (3), 759-773CODEN: JCSCEB; ISSN:1040-7278. (Springer)The spin-orbit splitting and magnetism of a single 3d, 4d impurity (Sc-Zn, Y-Cd) encapsulated in an icosahedral Ag12 cage (M@Ag12) are explored by methods based on d. functional theory. The large spin-orbit splittings of HOMO levels can be found in the clusters with heavy impurities in each series, esp. for 4d case. The total and local spin magnetic moments of 3d series are hardly affected by spin-orbit coupling (SOC). The similar scenario can take place for the 1st clusters of 4d series (Y-Mo@Ag12). For Tc-Pd@Ag12, the total and local spin magnetic moments remarkably decrease when SOC is considered. The magnetism of Ag@Ag12 and Cd@Ag12 hardly changes when the SOC is included despite large at. no. of the centric Ag and Cd, which can be ascribed to the closed d orbitals of Ag and Cd atoms. The densities of states of some typical clusters and orbital components for HOMO levels of all clusters were calcd. to understand these phenomena. The calcd. spin and orbital magnetic moments can be comprehended in accordance with the Hund's rule of superatom model. The closed-shell electron configuration is formed in Mo@Ag12 cluster according to 18-electron rule, quenching both its spin and orbital moments.
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736Sun, Q.; Wang, Q.; Yu, J. Z.; Li, Z. Q.; Wang, J. T.; Kawazoe, Y. Local magnetism of 3d and 4d impurities in Ag and Pd clusters. J. Phys. I 1997, 7, 1233– 1244, DOI: 10.1051/jp1:1997120736https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXnsVOjsbw%253D&md5=a51da5b599086a5c22da2a67a01c4061Local magnetism of 3d and 4d impurities in Ag and Pd clustersSun, Q.; Wang, Q.; Yu, J.Z.; Li, Z.Q.; Wang, J.T.; Kawazoe, Y.Journal de Physique I (1997), 7 (10), 1233-1244CODEN: JPGCE8; ISSN:1155-4304. (Editions de Physique)The local magnetic properties of Ag12TM and Pd12TM clusters with Ih symmetry (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh, and Pd) were systematically studied with the d. functional formalism, and the Kohn-Sham equation is solved self-consistently with the discrete variational method (DVM). A special attention is paid to the comparisons of local magnetism for impurities in Ag and Pd clusters with those in the bulk and on the (001) surface of Ag (Pd), the behavior of local moments in the Ag12 cluster is more complex than the one of a single impurity in bulk Ag and on the Ag(001)surface, whereas the local moments in Pd12 display very similar features as the ones of a single impurity in bulk Pd and on the Pd(001) surface. To better understand these results, the roles of interactions between impurity and host atoms on the local moment of impurities are explored: the interactions of impurity-d with Ag-d orbitals have important contributions to the local magnetic moments for impurities with less than half-filled d shell, such as Sc, Ti, V, Y, Zr and Nb, but have minor roles on the local magnetic moments for impurities Cr, Mn, Fe, Co, Ni, Tc, Ru and Rh. However, in the Pd12 cluster, d-d interactions between impurity and host have major roles on all the 3d and 4d impurities. Based on the interaction point of view, explanations are presented for the similarities and differences of monument behavior in the cluster, in the bulk and on the surface. The comparison of the obtained results with those in the Cu12 cluster is also made. This study would provide more comprehensive understandings on the local magnetism of 3d and 4d impurities in different environments.
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737Harb, M.; Rabilloud, F.; Simon, D. Structural, electronic, magnetic and optical properties of icosahedral silver-nickel nanoclusters. Phys. Chem. Chem. Phys. 2010, 12, 4246– 4254, DOI: 10.1039/b912971e737https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXksVCrurc%253D&md5=195b006c56e29959f30c1d27b94fafd0Structural, electronic, magnetic and optical properties of icosahedral silver-nickel nanoclustersHarb, Moussab; Rabilloud, Franck; Simon, DanielPhysical Chemistry Chemical Physics (2010), 12 (16), 4246-4254CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The authors present a systematic study of the structural, electronic, magnetic and optical properties of icosahedral bimetallic Ag(13-p)Nip (p ≤ 6) clusters in the gas phase studied in the framework of d. functional theory (DFT and TDDFT). In the most-stable structures, the central position is occupied by a nickel atom. The evolution of spin-multiplicities and local at. spin densities with Ag/Ni compn. are discussed. The evolution of the optical properties with the Ag/Ni compn. and the spatial positions of Ni atoms are analyzed. An interpretation of spectroscopic patterns in terms of contribution from s- and d-type excitations is also given. In particular the d-electrons of nickel atoms play a crucial role in the optical transitions of Ni-rich systems. Finally, the theor. spectra are compared to the exptl. ones for large Ni-core/Ag-shell clusters (∼2-5 nm in size).
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738Medel, V. M.; Reber, A. C.; Chauhan, V.; Sen, P.; Koester, A. M.; Calaminici, P.; Khanna, S. N. Nature of valence transition and spin moment in AgnV+ clusters. J. Am. Chem. Soc. 2014, 136, 8229– 8236, DOI: 10.1021/ja412064c738https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXotVahu7g%253D&md5=80cdc4373cd2de935c68ededb9cf0ac4Nature of Valence Transition and Spin Moment in AgnV+ ClustersMedel, Victor M.; Reber, Arthur C.; Chauhan, Vikas; Sen, Prasenjit; Koster, Andreas M.; Calaminici, Patrizia; Khanna, Shiv N.Journal of the American Chemical Society (2014), 136 (23), 8229-8236CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Evolution in the at. structure, bonding characteristics, stability, and the spin magnetic moment of neutral and cationic AgnV (n = 4-15) clusters were investigated using first-principles DFT-GGA-PW86 method. It is shown that at small sizes, the V 4s states hybridize with Ag states to form 1S and 1P like superat. orbitals, whereas the 3d states are localized on V giving the V atom an effective valence of 1 or 2. Starting from Ag8V+, the V 3d states begin to participate in the bonding by hybridizing with the nearly free electron gas to form 1D superat. orbitals increasing the V atom effective valence toward 5. For the cationic clusters, this changing valence results in three shell closures that lead to stable species. These occur for cationic clusters contg. 5, 7, and 14 Ag atoms. The first two stable species correspond to filled 1S and 1P shells in two and three dimensions with a valence of 2 for V, whereas the closure at 14 Ag atoms correspond to filled 1S, 1P, and 1D shells with V site exhibiting a valence of 5. The transition from filled 1S and 1P shells to filled 1S, 1P, and 1D shells is confirmed by a quenching of the spin magnetic moment. The theor. findings are consistent with the obsd. drops in intensity in the mass spectrum of AgnV+ clusters after 5, 7, and 14 Ag atoms.
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739Xiong, R.; Die, D.; Xiao, L.; Xu, Y. G.; Shen, X. Y. Probing the structural, electronic, and magnetic properties of AgnV (n = 1-12) clusters. Nanoscale Res. Lett. 2017, 12, 625, DOI: 10.1186/s11671-017-2394-0739https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MzitFGmtg%253D%253D&md5=e894f33ed852f0025eed3218ab714ae2Probing the Structural, Electronic, and Magnetic Properties of Ag n V (n = 1-12) ClustersXiong Ran; Die Dong; Xiao Lu; Xu Yong-Gen; Shen Xu-YingNanoscale research letters (2017), 12 (1), 625 ISSN:1931-7573.The structural, electronic, and magnetic properties of Ag n V (n = 1-12) clusters have been studied using density functional theory and CALYPSO structure searching method. Geometry optimizations manifest that a vanadium atom in low-energy AgnV clusters favors the most highly coordinated location. The substitution of one V atom for an Ag atom in Ag n + 1 (n ≥ 5) cluster modifies the lowest energy structure of the host cluster. The infrared spectra, Raman spectra, and photoelectron spectra of Ag n V (n = 1-12) clusters are simulated and can be used to determine the most stable structure in the future. The relative stability, dissociation channel, and chemical activity of the ground states are analyzed through atomic averaged binding energy, dissociation energy, and energy gap. It is found that V atom can improve the stability of the host cluster, Ag2 excepted. The most possible dissociation channels are Ag n V = Ag + Ag n - 1V for n = 1 and 4-12 and Ag n V = Ag2 + Ag n - 2V for n = 2 and 3. The energy gap of Ag n V cluster with odd n is much smaller than that of Ag n + 1 cluster. Analyses of magnetic property indicate that the total magnetic moment of Ag n V cluster mostly comes from V atom and varies from 1 to 5 μ B. The charge transfer between V and Ag atoms should be responsible for the change of magnetic moment.
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740Dong, R.; Chen, X.; Zhao, H.; Wang, X.; Shu, H.; Ding, Z.; Wei, L. Structural, electronic and magnetic properties of AgnFe clusters (n ⩽ 15): Local magnetic moment interacting with delocalized electrons. J. Phys. B: At., Mol. Opt. Phys. 2011, 44, 035102, DOI: 10.1088/0953-4075/44/3/035102740https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXktlyksbk%253D&md5=9e2a216f17cfe961775fc98d69a0c84aStructural, electronic and magnetic properties of AgnFe clusters (n ≤ 15): local magnetic moment interacting with delocalized electronsDong, Ruibin; Chen, Xiaoshuang; Zhao, Huxian; Wang, Xiaofang; Shu, Haibo; Ding, Zonglin; Wei, LuJournal of Physics B: Atomic, Molecular and Optical Physics (2011), 44 (3), 035102/1-035102/7CODEN: JPAPEH; ISSN:0953-4075. (Institute of Physics Publishing)The size-dependent electronic, structural and magnetic properties of AgnFe (n ≤ 15) clusters were studied by using the d. functional theory (DFT) within the generalized gradient approxn. The starting structures were generated from empirical genetic algorithm simulations. The most stable structures were then selected from a no. of structural isomers based on the results of the further DFT calcns. The Fe atom prefers to stay at the center of the clusters. The 2-dimensional to 3-dimensional transition occurs at n = 6. The magnetic properties and the geometric structures are strongly correlated. For Ag10Fe, the total magnetic moment of the cluster is quenched. The reason is similar to the Kondo effect in bulk metal. Also, Ag10Fe is considered to be very stable according to the 18-electron counting rule.
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741Rodríguez-Kessler, P. L.; Pan, S.; Florez, E.; Cabellos, J. L.; Merino, G. Structural evolution of the rhodium-doped silver clusters AgnRh (n ≤ 15) and their reactivity toward NO. J. Phys. Chem. C 2017, 121, 19420– 19427, DOI: 10.1021/acs.jpcc.7b05048741https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtlWnsL%252FN&md5=6eca9b064eca13877cdc21536eafa1b5Structural Evolution of the Rhodium-Doped Silver Clusters AgnRh (n ≤ 15) and Their Reactivity toward NORodriguez-Kessler, P. L.; Pan, Sudip; Florez, Elizabeth; Cabellos, Jose Luis; Merino, GabrielJournal of Physical Chemistry C (2017), 121 (35), 19420-19427CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Structural properties of AgnRh (n ≤ 15) clusters are investigated using a successive growth algorithm coupled with d. functional theory computations. The structures of the clusters are revisited, including a detailed discussion of their electronic properties. In contrast to these previous contributions, the lowest energy structures of the clusters are planar for n = 3-6, while three-dimensional for n = 7 onward. Our present searches identify new lowest energy structures for n = 3-6 and 9-13. The most stable isomers are selected to study the adsorption of NO. The size-dependent reactivity of the clusters indicates that Rh atom acts as a more effective adsorption site for NO than Ag. Since the transition from Rh-exposed to Rh-encapsulated structures occurs at n = 9, the reactivity toward NO for AgnRh clusters with n ≤ 8 is considerably higher than that for the larger homologues. Doping of Agn clusters with Rh increases the reactivity toward NO adsorption.
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742Xiong, R.; Die, D.; Xu, Y.-G.; Zheng, B.-X.; Fu, Y.-C. Probing the structural, electronic and magnetic properties of AgnSc (n = 1-16) clusters. Phys. Chem. Chem. Phys. 2018, 20, 15824– 15834, DOI: 10.1039/C8CP02605J742https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXpslaqtLY%253D&md5=efd0cefb1f15b65793a2ff8984fe3f1dProbing the structural, electronic and magnetic properties of AgnSc (n = 1-16) clustersXiong, Ran; Die, Dong; Xu, Yong-Gen; Zheng, Ben-Xia; Fu, Yao-ChunPhysical Chemistry Chemical Physics (2018), 20 (23), 15824-15834CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)The structural, electronic and magnetic properties of AgnSc (n = 1-16) clusters have been studied on the basis of d. functional theory and the CALYPSO structure prediction method. The optimized geometry exhibits that the growth process of Sc-doped silver clusters have a periodic structural change. The Ag atom grows around a basically invariant cluster core in each growth cycle. The Sc atom has a tendency to occupy the most highly coordinated position in the ground state. The IR spectra, Raman spectra and photoelectron spectra of AgnSc clusters are forecasted and can be used to identify the structures of these clusters from expts. The global maxima of the dissocn. energy, the averaged binding energy and the gap of the energy level occur at n = 15 for the most stable AgnSc clusters, implying that the Ag15Sc can be perceived as a superatom. The magnetism anal. indicates that the magnetic moment of the Sc atom in AgnSc clusters decreases with the increase of the cluster. The change of the magnetic moment is proportional to the charge transfer between the Sc and Ag atoms.
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743Gao, Y.; Jiang, W.; Chen, L.; Wang, J.; Wang, Z. First-principles study on charge transfer in an actinide-containing superatom from surface-enhanced Raman scattering. J. Mater. Chem. C 2017, 5, 803– 806, DOI: 10.1039/C6TC04865J743https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFahtLjJ&md5=4c3ce9a5f097c7e0201d32ac84d5c61bFirst-principles study on charge transfer in an actinide-containing superatom from surface-enhanced Raman scatteringGao, Yang; Jiang, Wanrun; Chen, Lei; Wang, Jia; Wang, ZhigangJournal of Materials Chemistry C: Materials for Optical and Electronic Devices (2017), 5 (4), 803-806CODEN: JMCCCX; ISSN:2050-7534. (Royal Society of Chemistry)The 5f-element-contg. clusters, An@Ag14 (An = Ac-, Th, Pa+), can be viewed as superat. systems (1S21P61D10). Taking them to be the surface-enhanced Raman scattering (SERS) substrates, the charge-transfer states (1Dmetal → π*pyridine) can lead to SERS signal enhancement ∼104 for pyridine-Th@Ag14 complexes, which is found to be superior to that of pure silver systems.
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744Sun, Q.; Gong, X. G.; Zheng, Q. Q.; Sun, D. Y.; Wang, G. H. Local magnetic properties and electronic structures of 3d and 4d impurities in Cu clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 10896– 10904, DOI: 10.1103/PhysRevB.54.10896744https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XmsFOhsb0%253D&md5=a7f380b92d3adf75f977c3d8346d38d1Local magnetic properties and electronic structures of 3d and 4d impurities in Cu clustersSun, Q.; Gong, X. G.; Zheng, Q. Q.; Sun, D. Y.; Wang, G. H.Physical Review B: Condensed Matter (1996), 54 (15), 10896-10904CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The local magnetic properties and electronic structures of Cu12R clusters with Ih and Oh symmetries (R = Sm, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag) were systematically studied with the d.-functional formalism, and the Kohn-Sham equation is solved self-consistently with the discrete variational method. By calcg. the binding energies for 3d series, the icosahedral structure is more stable than the octahedron structure. Pd and Ag doping can enhance the stability of a cluster, and the alloying effects in such doped clusters have an important effect on binding energy. The electronic structures calcd. in equil. configurations show that the clusters with R = Cu, Cr, Mo, or Ag have closed electronic shells, while the others have open electronic shells. In particular, the authors have performed comprehensive calcns. on the local magnetism of impurities in a cluster, and found that the behavior of local magnetism for 3d and 4d impurities in Cu12 clusters is different from that in bulk as well as from that in Al12 clusters. In contrast to the d-d interaction picture for local magnetism in the d-band bulk host, there are more complicated interactions acting in clusters to affect the local magnetism of impurities: the interactions of the Cu-p orbital with R-spd orbitals play a crucial role on the local magnetic moment for impurities with more than a half-filled d shell, such as Mn, Fe, Co, Ni, Tc, Ru, and Rh; the interactions of the Cu-d orbital with R-spd orbitals contribute to the local magnetic moment for impurities with a less than half-filled d shell, such as Sc, Ti, V, Y, Zr, and Nb. The authors have also tested and discussed the Stoner-like criterion for the occurrence of a local moment in a cluster.
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745Holtzl, T.; Veldeman, N.; De Haeck, J.; Veszpremi, T.; Lievens, P.; Nguyen, M. T. Growth mechanism and chemical bonding in scandium-doped copper clusters: Experimental and theoretical study in concert. Chem. - Eur. J. 2009, 15, 3970– 3982, DOI: 10.1002/chem.200802372There is no corresponding record for this reference.
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746Janssens, E.; Lievens, P. Growth mechanisms for doped clusters. Adv. Nat. Sci.: Nanosci. Nanotechnol. 2011, 2, 023001, DOI: 10.1088/2043-6262/2/2/023001746https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXptFGktLw%253D&md5=56e5555598b9a8e8d00de4752b539caaGrowth mechanisms for doped clustersJanssens, Ewald; Lievens, PeterAdvances in Natural Sciences: Nanoscience and Nanotechnology (2011), 2 (2), 023001/1-023001/8CODEN: ANSNCK; ISSN:2043-6262. (Institute of Physics Publishing)A review. Structural growth mechanisms for metal doped nanoclusters are investigated in combined exptl. and theor. studies. In particular, silicon, copper and gold clusters incorporating a transition metal dopant atom are investigated: Sin X (X = Cu, V), CunSc+ and AunY+ with n < 20. The doped clusters are produced with a dual-target dual-laser vaporization source. Structural information about the doped nanoclusters is provided by IR multi-photon dissocn. spectroscopy. Their size and compn. dependent stability is studied with photofragmentation and mass spectrometry. A detailed understanding of the role of the dopant atom in the structural growth and in the electronic structure of the clusters is obtained by comparison with quantum chem. computations using d. functional theory.
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747Hirabayashi, S.; Ichihashi, M. Reactions of Ti- and V-doped Cu cluster cations with nitric oxide and oxygen: Size dependence and preferential NO adsorption. J. Phys. Chem. A 2016, 120, 1637– 1643, DOI: 10.1021/acs.jpca.6b00206747https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xjs1GqsLs%253D&md5=30e2ed34b0317e4dbb068223890b8f77Reactions of Ti- and V-Doped Cu Cluster Cations with Nitric Oxide and Oxygen: Size Dependence and Preferential NO AdsorptionHirabayashi, Shinichi; Ichihashi, MasahikoJournal of Physical Chemistry A (2016), 120 (10), 1637-1643CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Reactions of Cu cluster cations doped with an early transition metal atom, CunTi+ (n = 4-15) and CunV+ (n = 5-14, 16), with NO and O2 were studied at a near-thermal collision energy using a guided ion beam tandem mass spectrometer. Most of the clusters adsorb NO and O2 under single collision conditions, and this reaction is often followed by the release of Cu atoms. For both Ti- and V-doped Cu clusters, the total cross sections for the reaction with NO increase gradually with the cluster size up to n ≈ 11 and then decrease rapidly, whereas those with O2 are almost const. in n ≤ 12 and then decrease. The size dependence of the reactivity toward NO is found to correlate with that of the adsorption energy calcd. by the d. functional theory method; CunTi+ clusters exhibit the larger reaction cross sections when they have the larger adsorption energies. The calcns. of CunTi+ also show that a structural transition from a Ti-exposed structure to Ti-encapsulated one occurs around n = 12. A geometric property of the clusters, i.e., the position of the dopant atom, is a detg. factor of reactivity. The Ti- and V-doping dramatically improves the reactivity of Cu cluster cations toward NO but it does not affect that toward O2 significantly. As a result, most of the Ti- and V-doped Cu clusters are more reactive toward NO than toward O2. The authors also studied the multiple-collision reaction of Cu7Ti+ with NO and obtained the cluster dioxide, Cu3TiO2+, as a product ion, which suggests that the dissocn. of NO and the subsequent formation/release of N2 take place.
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748Pham, H. T.; Cuong, N. T.; Tam, N. M.; Tung, N. T. A systematic investigation on CrCun clusters with n = 9-16: Noble gas and tunable magnetic property. J. Phys. Chem. A 2016, 120, 7335– 7343, DOI: 10.1021/acs.jpca.6b04221748https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVSgtbfL&md5=623771a2767029cfc5b31a73b1b9a81fA Systematic Investigation on CrCun Clusters with n = 9-16: Noble Gas and Tunable Magnetic PropertyPham, Hung Tan; Cuong, Ngo Tuan; Tam, Nguyen Minh; Tung, Nguyen ThanhJournal of Physical Chemistry A (2016), 120 (37), 7335-7343CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)A systematic investigation on structure, dissocn. behavior, chem. bonding, and magnetic property of Cr-doped Cun clusters (n = 9-16) is carried out using the mean of d. functional theory calcns. It is found that CrCu12 is a crucial size, preferring an icosahedral Cu12 cage with the central Cr dopant. Smaller cluster sizes appear as on the way to form the CrCu12 icosahedron while larger ones are produced by attaching addnl. Cu atoms to the CrCu12 core. The presence of Cr dopant obviously enhances the stability of CrCun clusters in comparison to that of pure counterparts. Exceptionally stable CrCu12 has an 18-electron closed-shell electronic structure, mimicking a noble gas in the viewpoint of superatom concept. Anal. on cluster electronic structure shows that the interplay between 3d orbitals of Cr and 4s orbitals of Cu has a vital role on the magnetic properties of CrCun clusters.
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749Sarugaku, S.; Murakami, R.; Matsumoto, J.; Kawano, T.; Arakawa, M.; Terasaki, A. Size-dependent reactivity of nickel-doped silver cluster cations toward oxygen: Electronic and geometric effects. Chem. Lett. 2017, 46, 385– 388, DOI: 10.1246/cl.161094749https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVGrtb7J&md5=03396b8554c0667392312f7d5275c5a2Size-dependent Reactivity of nickel-doped silver cluster cations toward oxygen: electronic and geometric effectsSarugaku, Shun; Murakami, Ryohei; Matsumoto, Jumpei; Kawano, Tomoki; Arakawa, Masashi; Terasaki, AkiraChemistry Letters (2017), 46 (3), 385-388CODEN: CMLTAG; ISSN:0366-7022. (Chemical Society of Japan)Size-dependent reaction of nickel-doped silver cluster cations (AgN-1Ni+: N = 5-14) was investigated for oxygen as the reactant mol. A dramatic drop in the reactivity obsd. for N ≥ 9 is attributed to the encapsulation of the nickel atom, i.e., screening the active site at larger sizes. The reactivity min. obsd. at N = 10 is ascribed to the closed electronic shell of Ag9Ni+ formed by 18 valence electrons from Ag5s, Ni4s, and Ni3d, suggesting delocalized d electrons.
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750Graciani, J.; Oviedo, J.; Sanz, J. F. V@Au12-: An improved novel catalyst for CO oxidation?. J. Phys. Chem. B 2006, 110, 11600– 11603, DOI: 10.1021/jp057322f750https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XkslWlt70%253D&md5=729ac56b77e3a73b9fd1aef42a4fef1eV@Au12-: An Improved Novel Catalyst for CO Oxidation?Graciani, Jesus; Oviedo, Jaime; Sanz, Javier F.Journal of Physical Chemistry B (2006), 110 (23), 11600-11603CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)The catalytic properties toward CO combustion of an encapsulated cluster, V@Au12-, have been explored by means of plane-wave pseudopotential d.-functional theory calcns. Single adsorption of both O2 and CO as well as coadsorption have been considered. The adsorption energy for the O2 mol. is about 0.3-0.4 eV which limits its use to low temps. However, in contrast to what happens for pure gold clusters, this system shows a remarkable capacity to bind a high no. of oxygen mols. Moreover, its icosahedral cluster is able to bind 12 CO mols., since all of the gold atoms are available. The bond between the metal cluster and the oxygen mol. mainly arises from a charge transfer from the metal toward the πg antibonding O2 orbitals, while in the case of CO mol., the classical σ-donation π-back-donation mechanism is obsd. Finally, no coadsorption effects are found when both mols. are adsorbed, the interaction properties between the cluster and the substrates remain basically unaltered.
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751Gao, Y.; Shao, N.; Bulusu, S.; Zeng, X. C. Effective CO oxidation on endohedral gold-cage nanoclusters. J. Phys. Chem. C 2008, 112, 8234– 8238, DOI: 10.1021/jp801262v751https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlvFSgtLk%253D&md5=a40798b8246f2d211f71b5883a2312b8Effective CO Oxidation on Endohedral Gold-Cage NanoclustersGao, Yi; Shao, Nan; Bulusu, Satya; Zeng, X. C.Journal of Physical Chemistry C (2008), 112 (22), 8234-8238CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Ab initio calcns. are performed to study the CO oxidn. on six endohedral gold-cage clusters (W@Au12, Nb@Au13, Zr@Au14, Sc@Au15, Ca@Au16, and Na@Au17). The calcns. suggest that three clusters (Nb@Au13, Zr@Au14, and Sc@Au15) can be very effective nanocatalysts. The reaction energy barriers are lower than those assocd. with either bare gold clusters or gold surfaces and are comparable to those assocd. with the support Au clusters. The effective CO oxidn. can be attributed to the charge transfer from the dopant to the gold cage, the low coordination no. for gold atoms on the cages, as well as the fluxionality of the cage.
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752Kim, H. Y.; Kim, D. H.; Ryu, J. H.; Lee, H. M. Design of robust and reactive nanoparticles with atomic precision: 13Ag-Ih and 12Ag-1X (X = Pd, Pt, Au, Ni, or Cu) Core-Shell Nanoparticles. J. Phys. Chem. C 2009, 113, 15559– 15564, DOI: 10.1021/jp905047h752https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXps1Klurw%253D&md5=68d14edf025c3d9e933c338f98f4f807Design of Robust and Reactive Nanoparticles with Atomic Precision: 13Ag-Ih and 12Ag-1X (X = Pd, Pt, Au, Ni, or Cu) Core-Shell NanoparticlesKim, Hyun You; Kim, Da Hye; Ryu, Ji Hoon; Lee, Hyuck MoJournal of Physical Chemistry C (2009), 113 (35), 15559-15564CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)D. functional theory calcns. and a modified reaction model confirm that the initial high CO oxidn. reactivity of a 13Ag-Ih nanoparticle from an icosahedron (Ih) structure is immediately diminished as the nanoparticle is transformed to an amorphous state by a reaction-driven structural change. The adsorption of O2 and the formation of a four-center intermediate metastable state from coadsorbed CO and O2 pos. charge the 13Ag-Ih nanoparticle, and the repulsive force between the Ag atoms causes the reaction-driven structural change of the 13Ag-Ih nanoparticle. When one central Ag atom is substituted with a solute atom, a core-shell type of 12Ag-1X-Ih (X = Pd, Pt, Au, Ni, or Cu) bimetallic nanoparticle is stabilized. Among them, the authors propose the 12Ag-1Pd nanoparticle as a robust and reactive Ag-based bimetallic nanoparticle for CO oxidn. The structural fluxionality accounts for the catalytic activity of small nanoparticles.
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753Kim, H. Y.; Han, S. S.; Ryu, J. H.; Lee, H. M. Balance in adsorption energy of reactants steers CO oxidation mechanism of Ag13 and Ag12Pd1 nanoparticles: Association mechanism versus carbonate-mediated mechanism. J. Phys. Chem. C 2010, 114, 3156– 3160, DOI: 10.1021/jp9111553753https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlKku7k%253D&md5=23e542cccd65e27e19aa39ec89492117Balance in Adsorption Energy of Reactants Steers CO Oxidation Mechanism of Ag13 and Ag12Pd1 Nanoparticles: Association Mechanism versus Carbonate-Mediated MechanismKim, Hyun You; Han, Sang Soo; Ryu, Ji Hoon; Lee, Hyuck MoJournal of Physical Chemistry C (2010), 114 (7), 3156-3160CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)CO oxidn. is a very useful ref. reaction for catalysis by nanoparticles (NP). Two reaction models (assocn. mechanism [AM] and carbonate-mediated mechanism [CMM]) have been suggested for CO oxidn. catalyzed by small NP; however, it is unclear when and why these mechanisms preferentially operate. For Ag13 cryst. NP and Ag12Pd1 core-shell NP, a d. functional theory calcn. and micro-kinetic reaction model detd. the different reaction mechanisms can operate with different reaction intermediates, accompanied by a balance in the adsorption energy of reactants. Adsorption energy of adsorbates variations can result from the interchange of the 2 reaction mechanisms, even in a single NP. An AM operates when both reactants interact strongly with a NP; the contribution of the CMM in CO oxidn. increases when a CO mol. interacts weakly or not at all with a NP.
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754Zhou, S.; Pei, W.; Du, Q.; Zhao, J. Foreign atom encapsulated Au12 golden cages for catalysis of CO oxidation. Phys. Chem. Chem. Phys. 2019, 21, 10587– 10593, DOI: 10.1039/C9CP01517E754https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXosVCgtbo%253D&md5=f08e9b9085eb3b9971786c4d990eb577Foreign atom encapsulated Au12 golden cages for catalysis of CO oxidationZhou, Si; Pei, Wei; Du, Qiuying; Zhao, JijunPhysical Chemistry Chemical Physics (2019), 21 (20), 10587-10593CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Gold clusters are known for their unique catalytic properties, among which, endohedral gold clusters doped with heteroatoms have remarkable stabilities, with electronic structures tunable by both cluster size and doping element. Thus, it is intriguing and imperative to understand the principles for modulating the catalytic behaviors of these novel clusters. Here, we exploit exptl. produced M@Au12 (M = transition metal) cage clusters for catalysis of CO oxidn. The doping effects of 3d, 4d and 5d transition metals (V, Cr, Mn, Nb, Mo, Ta, W and Re) on the catalytic properties were systematically explored by first-principles calcns. Among the considered M@Au12 clusters, Cr@Au12 and Mn@Au12 provide a suitable binding strength with reaction intermediates and are highly active for CO oxidn. with reaction barriers of 0.41 eV under the Langmuir-Hinshelwood mechanism. More importantly, we establish a distinct relationship between catalytic activity and the M-Au bond order and the d orbital center of the M@Au12 clusters, which would help tailor their catalytic performance with atomistic precision and enable utilization of these stable gold cages for catalysis of various chem. processes.
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755Fu, Y.; Li, J.; Wang, S.-G. Bonding and electronic structures in W@Au12 AE complexes (AE = NO+, CO, BF, CN-, or BO-): Analogies among ligands isoelectronic to carbon monoxide. J. Mol. Model. 2010, 16, 9– 16, DOI: 10.1007/s00894-009-0517-y755https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXlslGitbw%253D&md5=5f7edc6495b90eb393f1b6dddfb876b8Bonding and electronic structures in W@Au12AE complexes (AE= NO+, CO, BF, CN-, or BO-): analogies among ligands isoelectronic to carbon monoxideFu, Yi; Li, Jia; Wang, Shu-GuangJournal of Molecular Modeling (2010), 16 (1), 9-16CODEN: JMMOFK; ISSN:0948-5023. (Springer GmbH)A theor. study on the geometries and electronic structures of W@Au12AE (AE = NO+, BF, CN-, or BO-) was carried out to gain insight into interactions between W@Au12 and ligands isoelectronic with CO. The best configuration for the adsorption site is on-top type for all five complexes. After complexing with boron ligands (BF or BO-), the axial Au-W bond distance in W@Au12 is lengthened notably, but NO+ has the opposite effect on the axial Au-W bond. A charge transfer and energy decompn. anal. shows that the metal-ligand bonds have enhanced σ-donation strength from NO+ to BO-. Furthermore, the A-E bond strength in the complexes becomes weaker with stronger π-back-donation interactions. Finally, W@Au12CO has the largest HOMO-LUMO gap, making it the most stable in terms of kinetic stability.
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756Sinai, H. E.; Avnir, D. Adsorption-induced symmetry distortions in W@Au12 nanoclusters, leading to enhanced hyperpolarizabilities. Isr. J. Chem. 2016, 56, 1076– 1081, DOI: 10.1002/ijch.201600082There is no corresponding record for this reference.
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757Chen, L.; Gao, Y.; Cheng, Y.; Su, Y.; Wang, Z.; Li, Z.; Zhang, R.-Q. Strong core@shell dependence in surface-enhanced raman scattering of pyridine on stable 13-atom silver-caged bimetallic clusters. J. Phys. Chem. C 2015, 119, 17429– 17437, DOI: 10.1021/acs.jpcc.5b04453757https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFWqt7nP&md5=503ebe41a3aaa32a484a80fd19fd047dStrong Core@Shell Dependence in Surface-Enhanced Raman Scattering of Pyridine on Stable 13-Atom Silver-Caged Bimetallic ClustersChen, Lei; Gao, Yang; Cheng, Yingkun; Su, Yanbin; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-QinJournal of Physical Chemistry C (2015), 119 (30), 17429-17437CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)From calcns. using time-dependent d. functional theory, the authors conducted detailed analyses of the surface-enhanced Raman scattering (SERS) of pyridine adsorbed on 13-atom icosahedral M@Au12 and M@Ag12 (M = Mo, W) clusters. Surprisingly, although the SERS enhancements for all complexes can reach the order of 104, the signals of pyridine on M@Ag12 at charge transfer (CT) transition excitations are twice as much as that of pyridine on M@Au12, and the corresponding energies used for SERS excitations are significantly different in the low-energy region of 1.63-2.10 eV. The interactive modulation between the core and shell can produce varying strong CT transitions from metal clusters to pyridine, which tunes the SERS enhancements with altered optical properties. The complexes of pyridine on Ag-caged clusters are more easily influenced by the tunability of the core than that of pyridine on Au-caged clusters. Analyses are expected to provide a theor. basis for exptl. synthesizing multicomponent SERS substrates and exploring the dependence of SERS enhancement on the synergies between the different components in core@shell binary metal clusters.
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758Chen, L.; Gao, Y.; Cheng, Y.; Li, H.; Wang, Z.; Li, Z.; Zhang, R.-Q. Nonresonant chemical mechanism in surface-enhanced Raman scattering of pyridine on M@Au12 clusters. Nanoscale 2016, 8, 4086– 4093, DOI: 10.1039/C5NR07246H758https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XlvV2gtQ%253D%253D&md5=bd8ecedbfd7d98570c67440438ef91ceNonresonant chemical mechanism in surface-enhanced Raman scattering of pyridine on M@Au12 clustersChen, Lei; Gao, Yang; Cheng, Yingkun; Li, Haichao; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-QinNanoscale (2016), 8 (7), 4086-4093CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)By employing d. functional theory (DFT), this study presents a detailed anal. of nonresonant surface-enhanced Raman scattering (SERS) of pyridine on M@Au12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, and Re+)-the stable 13-atom neutral and charged gold buckyball clusters. Changing the core atom in M@Au12 enabled us to modulate the direct chem. interactions between pyridine and the metal cluster. The results of our calcns. indicate that the ground-state chem. enhancement does not increase as the binding interaction strengthens or the transfer charge increases between pyridine and the cluster. Instead, the magnitude of the chem. enhancement is governed, to a large extent, by the charged properties of the metal clusters. Pyridine on M@Au12 anion clusters exhibits strong chem. enhancement of a factor of about 102, but the equiv. increase for pyridine adsorbed on M@Au12 neutral and cation clusters is no more than 10. Polarizability and deformation d. analyses clearly show that compared with the neutral and cation clusters, the anion clusters have more delocalized electrons and occupy higher energy levels in the pyridine-metal complex. Accordingly, they produce larger polarizability, leading to a stronger nonresonant enhancement effect.
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759Chen, L.; Wang, Z.; Li, Z.; Zhang, R.-Q. Chemical coupling SERS properties of pyridine on silver-caged metal clusters M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+). J. Electron. Mater. 2017, 46, 3904– 3909, DOI: 10.1007/s11664-016-4993-4759https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1OisL3K&md5=79ffba8702aa132ddd8acc9c26aacc03Chemical Coupling SERS Properties of Pyridine on Silver-Caged Metal Clusters M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+)Chen, Lei; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-QinJournal of Electronic Materials (2017), 46 (7), 3904-3909CODEN: JECMA5; ISSN:0361-5235. (Springer)Using d. functional theory, this work presents a comprehensive anal. of nonresonant surface-enhanced Raman scattering enhancement of pyridine on M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+). Computational results indicate that the chem. enhancement of pyridine on M@Ag12 is closely assocd. with the charge properties of silver-caged clusters. Pyridine on neg. clusters exhibits the strongest chem. enhancement with a factor of about 103, while the chem. enhancement is only about 102 for pyridine on neutral clusters and 10 for pyridine on pos. clusters. The polarizability analyses elucidate the nature of the chem. enhancement that delocalized electrons of neg. adsorption systems occupy higher MOs than those of neutral and pos. adsorption systems, which can lead to stronger nonresonant chem. enhancement.
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760Jensen, F.; Toftlund, H. Structure and stability of C24 and B12N12 isomers. Chem. Phys. Lett. 1993, 201, 89– 96, DOI: 10.1016/0009-2614(93)85039-Q760https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXosl2htw%253D%253D&md5=373f469f7099b26dc8487e616e593386Structure and stability of carbon (C24) fullerene and boron nitride (B12N12) fullerene isomersJensen, Frank; Toftlund, HansChemical Physics Letters (1993), 201 (1-4), 89-96CODEN: CHPLBC; ISSN:0009-2614.The structures and stabilities of four possible isomers of C24 and B12N12 were studied by means of ab-initio calcns. at the MP2/DZP level. The four geometries are a monocyclic ring, a graphite-like sheet, and two fullerene structures. For C24, the graphite-like isomer is lowest in energy; while a B12N12 fullerene consisting of 4- and 6-membered rings appears to be quite stable. It is possible that this fullerene plays the same role for boron nitride as C60 does for carbon.
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761Silaghi-Dumitrescu, I.; Haiduc, I.; Sowerby, D. B. Fully inorganic (carbon-free) fullerenes? The boron-nitrogen case. Inorg. Chem. 1993, 32, 3755– 3758, DOI: 10.1021/ic00069a034761https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlsFWit7o%253D&md5=8c49a16f5405bad1dea05b7567bf7075Fully inorganic (carbon-free) fullerenes? The boron-nitrogen caseSilaghi-Dumitrescu, Ioan; Haiduc, Ionel; Sowerby, D. BryanInorganic Chemistry (1993), 32 (17), 3755-8CODEN: INOCAJ; ISSN:0020-1669.Closed cages contg. only B and N atoms can be constructed from 4-membered B2N2 rings and 6-membered B3N3 rings. The ring-spiral algorithm applied to such cages and HMO calcns. suggest that stable accordion-shaped cages, B12+3nN12+3n can exist. From different principles, a B22N22 cage seems also possible.
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762Sun, M.-L.; Slanina, Z.; Lee, S.-L. Square/hexagon route towards the boron-nitrogen clusters. Chem. Phys. Lett. 1995, 233, 279– 283, DOI: 10.1016/0009-2614(94)01441-W762https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjs1Crsbo%253D&md5=772602172d842ce326269fa7d269382aSquare/hexagon route towards the boron-nitrogen clustersSun, Mei-Ling; Slanina, Zdenek; Lee, Shyi-LongChemical Physics Letters (1995), 233 (3), 279-83CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)A new route towards B/N clusters is considered, based on squares and hexagons. The pattern always requires six squares while the no. of hexagons increases linearly with the no. of atoms. The route can produce species of similar or even higher stability compared to the conventional pentagon-hexagon pattern. Four particular stoichiometries emerge from the available Austin-model-one-MO (AM1) computations: B12N12, B28N28, B36N36, and B36N24.
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763Seifert, G.; Fowler, P.; Mitchell, D.; Porezag, D.; Frauenheim, T. Boron-nitrogen analogues of the fullerenes: Electronic and structural properties. Chem. Phys. Lett. 1997, 268, 352– 358, DOI: 10.1016/S0009-2614(97)00214-5763https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXis1Wmt7w%253D&md5=d768cbd9bfb5a87c2fe588db5cc7faf3Boron-nitrogen analogs of the fullerenes: electronic and structural propertiesSeifert, G.; Fowler, P. W.; Mitchell, D.; Porezag, D.; Frauenheim, Th.Chemical Physics Letters (1997), 268 (5,6), 352-358CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)On the basis of a systematic d. functional tight-binding study of boron-nitrogen polyhedra (BN)x composed entirely of four- and six-membered rings, it is predicted that octahedron-like structures B12N12, B16N16 and B28N28 are "magic" (i.e. anomalously stable) clusters. The IR spectrum of B12N12 is predicted. The similarities and differences between these "inorg. fullerenes" and the carbon-based equiv. are outlined. A high stability of the (BN)x clusters is found to correlate with a large HOMO-LUMO gap.
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764Stephan, O.; Bando, Y.; Loiseau, A.; Willaime, F.; Shramchenko, N.; Tamiya, T.; Sato, T. Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material. Appl. Phys. A: Mater. Sci. Process. 1998, 67, 107– 111, DOI: 10.1007/s003390050745764https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXktFKrsLk%253D&md5=48134849d1124be36cb3df6c18d559cbFormation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk materialStephan, O.; Bando, Y.; Loiseau, A.; Willaime, F.; Shramchenko, N.; Tamiya, T.; Sato, T.Applied Physics A: Materials Science & Processing (1998), 67 (1), 107-111CODEN: APAMFC; ISSN:0947-8396. (Springer-Verlag)An exptl. evidence for the formation of small BN cage-like mols., under electron-irradn. expts. of BN samples, is presented. Depending on the starting material, either close-packed agglomerates of small fullerene-like compds., or small nested fullerene-like compds. with ≤6 layers are found as irradn. derivs. The overall polyhedral shape of the BN cages is explained within the frame of the octahedral model previously proposed for BN analogs to fullerenes. The diams. of the smallest and most obsd. cages range from 0.4-0.7 nm, and are close to those of the B12N12B16N16 and B28N28 octahedra which were predicted to be magic clusters for the BN system from electronic structure calcns.
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765Golberg, D.; Bando, Y.; Stephan, O.; Kurashima, K. Octahedral boron nitride fullerenes formed by electron beam irradiation. Appl. Phys. Lett. 1998, 73, 2441– 2443, DOI: 10.1063/1.122475765https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXms1eqsrs%253D&md5=0cd0c4ef20917d2a8e78f4d449f6b349Octahedral boron nitride fullerenes formed by electron beam irradiationGolberg, D.; Bando, Y.; Stephan, O.; Kurashima, K.Applied Physics Letters (1998), 73 (17), 2441-2443CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Formation is reported of fullerenes with a reduced no. of layers (typically ≤3) in boron nitride (BN) which was subjected to in situ electron irradn. at 20 and 490 °C in a high resoln. 300 kV transmission electron microscope (HRTEM). The BN fullerenes exhibited B/N stoichiometry of ∼1 as confirmed by electron energy loss spectroscopy using a 1 nm electron probe. The fullerene HRTEM images revealed rectangle-like shapes when viewed in specific projections, unlike the quasispherical carbon fullerene morphol. The octahedral BN fullerene model of O. Stephan et al. (1998) is verified by the BN fullerene observations at different viewing angles.
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766Oku, T.; Kuno, M.; Narita, I. High-resolution electron microscopy and electronic structures of endohedral La@B36N36 clusters. Diamond Relat. Diamond Relat. Mater. 2002, 11, 940– 944, DOI: 10.1016/S0925-9635(01)00609-4766https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjvVemsrY%253D&md5=84827840f0b0009de9a2d5676a4c295dHigh-resolution electron microscopy and electronic structures of endohedral La@B36N36 clustersOku, Takeo; Kuno, Masaki; Narita, IchihitoDiamond and Related Materials (2002), 11 (3-6), 940-944CODEN: DRMTE3; ISSN:0925-9635. (Elsevier Science S.A.)La@36N36 endohedral metallofullerenes were synthesized for the first time, which was obsd. by high-resoln. electron microscopy, and a structure model was proposed. Image simulations of the La@36N36 clusters also showed the possible existence of a La atom inside the BN clusters. At. structures, structural stabilities and electronic structures of La@36N36, Fe@36N36 and B36N36 clusters were investigated by mol. mechanics and MO calcns., which showed that the B36N36 clusters are expanded by introducing doping atoms and the energy gap of B36N36 is reduced by introducing La and Fe atoms inside the B36N36 cluster.
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767Oku, T.; Kuno, M. Synthesis, argon/hydrogen storage and magnetic properties of boron nitride nanotubes and nanocapsules. Diamond Relat. Mater. 2003, 12, 840– 845, DOI: 10.1016/S0925-9635(02)00326-6767https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjsVeku78%253D&md5=07dc739da29264915d442f7f7e308f64Synthesis, argon/hydrogen storage and magnetic properties of boron nitride nanotubes and nanocapsulesOku, Takeo; Kuno, MasakiDiamond and Related Materials (2003), 12 (3-7), 840-845CODEN: DRMTE3; ISSN:0925-9635. (Elsevier Science B.V.)BN fullerene materials such as nanotubes, nanocapsules and nanocages were synthesized from LaB6, Co, Pd, Ti, Ni or Cu catalyst with boron powder by using an arc-melting method under an Ar-N atm.. For the BN nanocapsules with Co and CoOx nanoparticles, argon was detected by energy dispersive x-ray spectroscopy, and the nanocapsules had superparamagnetic properties. Thermogravimetry/differential thermogravimetric anal. of BN nanomaterials produced from LaB6 and Pd/boron powder showed the possibility of hydrogen storage of ∼3 wt.%.
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768Oku, T.; Narita, I.; Nishiwaki, A. Formation and structures of B36N36 and Y@B36N36 clusters studied by high-resolution electron microscopy and mass spectrometry. J. Phys. Chem. Solids 2004, 65, 369– 372, DOI: 10.1016/j.jpcs.2003.09.010768https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmsFOitQ%253D%253D&md5=160ce9791b950812d80557a6a57b3fdaFormation and structures of B36N36 and Y@B36N36 clusters studied by high-resolution electron microscopy and mass spectrometryOku, Takeo; Narita, Ichihito; Nishiwaki, AtsushiJournal of Physics and Chemistry of Solids (2004), 65 (2-3), 369-372CODEN: JPCSAW; ISSN:0022-3697. (Elsevier Science B.V.)High-resoln. electron microscopy, mass spectrometry and mol. mechanics/orbital calcns. of the boron nitride-based clusters showed the formation of B36N36 and YB36N36. Image simulations of these clusters confirmed the proposed structure model.
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769Oku, T.; Nishiwaki, A.; Narita, I. Formation and atomic structures of BnNn (n = 24–60) clusters studied by mass spectrometry, high-resolution electron microscopy and molecular orbital calculations. Phys. B 2004, 351, 184– 190, DOI: 10.1016/j.physb.2004.06.007769https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmt1WlsrY%253D&md5=20ec78d30dbd1d3a46e77d46b98ec0fbFormation and atomic structures of BnNn (n = 24-60) clusters studied by mass spectrometry, high-resolution electron microscopy and molecular orbital calculationsOku, Takeo; Nishiwaki, Atsushi; Narita, IchihitoPhysica B: Condensed Matter (Amsterdam, Netherlands) (2004), 351 (1-2), 184-190CODEN: PHYBE3; ISSN:0921-4526. (Elsevier)Boron nitride (BN) nanocage clusters (BnNn: n = 24-60) were synthesized by arc-melting method and detected by mass spectrometry and high-resoln. electron microscopy. Endohedral boron nitride clusters Y@BnNn would also be formed. The BN clusters consist of 4-, 6- and 8-membered BN rings satisfying the isolated tetragonal rule, which was optimized by MO calcns. The electronic structure showed that bandgap energies increase with increase of cluster size.
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770Beheshtian, J.; Tabar, M. B.; Bagheri, Z.; Peyghan, A. A. Exohedral and endohedral adsorption of alkaline earth cations in BN nanocluster. J. Mol. Model. 2013, 19, 1445– 1450, DOI: 10.1007/s00894-012-1702-y770https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtlWns7s%253D&md5=12b6af2a615d92a97fd5134b6742a7b2Exohedral and endohedral adsorption of alkaline earth cations in BN nanoclusterBeheshtian, Javad; Tabar, Mohammad Bigdeli; Bagheri, Zargham; Peyghan, Ali AhmadiJournal of Molecular Modeling (2013), 19 (3), 1445-1450CODEN: JMMOFK; ISSN:0948-5023. (Springer)Adsorption of three alk. earth cations inside and outside of a B12N12 nano-cage in aq. medium was investigated using d. functional theory. The results obtained are discussed in terms of thermodn., geometric, and electronic properties. Based on the calcn. of enthalpy changes at 298 K and 1 atm, the adsorption of the considered cations was found to be exothermic outside the cluster while it is endothermic inside. It was also found that the exohedral adsorption favorability of the cluster increases in the series: Ca2+ < Mg2+ << Be2+ with Gibbs free energy changes in the range of -0.08 to -1.53 eV at B3LYP/6-31G (d) level of theory. Overall, interaction of the cations with the cluster influences the electronic properties of the cluster through stabilizing the HOMO and LUMO as well as reducing the energy gap between them. However, the electronic properties changed much more in the case of endohedral adsorption in comparison with the exohedral adsorption.
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771Liu, Z.; Liu, X.; Zhao, J. Design of superhalogens using a core–shell structure model. Nanoscale 2017, 9, 18781– 18787, DOI: 10.1039/C7NR06431D771https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsl2ltb7N&md5=c0627f29ccef1c8cd42084090796c604Design of superhalogens using a core-shell structure modelLiu, Zhifeng; Liu, Xiaojuan; Zhao, JijunNanoscale (2017), 9 (47), 18781-18787CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)A review. Superhalogens, which have larger electron affinity than any halogen, play an important role in phys. chem. and materials design because of their applications in hydrogen storage and lithium-ion batteries. Inspired by the unique geometries and electronic properties of II-VI/III-V cage clusters, particularly the exptl. synthesized B12N12, we propose a core-shell structure model to design new superhalogens. The idea is assessed by conducting ab initio calcns. on endohedral cage clusters X@B12N12 (X = F, Cl, Br) and other similar systems. With an exceptionally large electron affinity of 5.36 eV, the stable F@B12N12 cluster behaves as a novel superhalogen that can serve as a building block for Li salts and hyperhalogens. The findings highlight a new route for the discovery of superhalogens and provide useful building blocks for the bottom-up design of materials.
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772Feng, L.; Lu, Y.; Kong, J.; Su, Z. Theoretical studies on the structure and properties of BN clusters (BN)n and endohedral metallo-BN clusters M@(BN)n. Comput. Theor. Chem. 2011, 964, 56– 64, DOI: 10.1016/j.comptc.2010.11.036772https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXitlartL0%253D&md5=37efc8e2818eadfe66ed7d5fe589b1a6Theoretical studies on the structure and properties of BN clusters (BN)n and endohedral metallo-BN clusters M@(BN)nFeng, Lei; Lu, Yinghua; Kong, Jun; Su, ZhongminComputational & Theoretical Chemistry (2011), 964 (1-3), 56-64CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)The structure, stabilities, aromaticity, IR, Raman, and electronic spectra of BN clusters (BN)n (n = 12, 16, 20, 24, 28, 36) and endohedral metal-doped BN clusters M@(BN)n (M = Ca, Zn) have been predicted within d. functional theory. The energy gap between the HOMO and the LUMO does not change much with the size of BN cluster. However, such gap changes with metal atom in metal-doped BN clusters. Blue-shift of major peaks in IR spectra and red-shift of major peaks in Raman and electronic spectra occur in those BN clusters. The effect of doping of different metal atoms on the properties of the doped BN cluster has been revealed by the doping of Ca and Zn in those clusters.
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773Wang, J.; Ma, L.; Zhao, J.; Wang, B.; Wang, G. Stability and magnetic properties of transition metal atoms endohedral BnNn (n = 12–28) cages. J. Chem. Phys. 2008, 128, 084306, DOI: 10.1063/1.2833981773https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtVGqt7k%253D&md5=6c7549fa16f993374c5780bbf5d0bc44Stability and magnetic properties of transition metal atoms endohedral BnNn (n = 12-28) cagesWang, Jianguang; Ma, Li; Zhao, Jijun; Wang, Baolin; Wang, GuanghouJournal of Chemical Physics (2008), 128 (8), 084306/1-084306/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)First-principles calcns. have been conducted to systemically investigate the stability and magnetic properties of 3d and 4d transitional-metal (TM) atoms doped in the BnNn (n = 12, 16, 20, 24, 28) cages. Among those cages, the B24N24 is the optimal one for encapsulating 3d and 4d TM atoms according to the computed heat of formation. Inside B24N24 cage, 3d and 4d TM dopants belonging to the same group in the Periodic Table exhibit similar magnetic behaviors. Most of the 3d and 4d TM atoms remain magnetic after doped in the B24N24 cage except for Ni, Zr, and Pd. The magnitudes of the remaining moments for 3d (except for Sc, Ti, and V) and 4d dopants are reduced from those of free atoms. The energy gaps are localized at the doped transition metal atoms. Encapsulations of two TM atoms inside the B24N24 cage were also considered. (c) 2008 American Institute of Physics.
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774Oliaey, A. R.; Boshra, A.; Khavary, M. Spin polarized bonding analysis of endohedral boron nitride nanocages: Density functional theory study. Phys. E 2010, 42, 2314– 2318, DOI: 10.1016/j.physe.2010.05.009774https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXos1GisLk%253D&md5=353cc9f00243ef3b11b9937baf63e01bSpin polarized bonding analysis of endohedral boron nitride nanocages: Density functional theory studyOliaey, Ahmad Reza; Boshra, Asadollah; Khavary, MahyarPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2010), 42 (9), 2314-2318CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)Spin polarized bonding anal. has been performed for B24N24 and its endohedral alkali metal derivs. (M@B24N24, M=Li, Na, K). The method used is d. functional theory (DFT) with hybrid functional B3LYP to evaluate spin-polarized natural bond orbitals (NBO). In the spin-polarized endohedral B24N24 models BN σ bonding occupancies decrease and the π bonding interactions vanish in the encapsulated cluster structure. The donor-acceptor interactions of NBOs change due to trapped atom. Encaged alkali atoms impact bonding characteristics of the nanocluster and establish new NBO interactions within the cluster structure.
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775Koi, N.; Oku, T.; Suganuma, K. s. Effects of endohedral element in B24N24 clusters on hydrogenation studied by molecular orbital calculations. Phys. E 2005, 29, 541– 545, DOI: 10.1016/j.physe.2005.06.023775https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFarsbvN&md5=347c707507cc77f5cd7337ba3c38920fEffects of endohedral element in B24N24 clusters on hydrogenation studied by molecular orbital calculationsKoi, Naruhiro; Oku, Takeo; Suganuma, Kat suakiPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2005), 29 (3-4), 541-545CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)Possibility of hydrogen gas storage in boron nitride (BN) clusters was investigated by MO calcns. Chemisorption calcn. was carried out for B24N24 with changing endohedral elements in BN cluster to compare the bonding energy at nitrogen and boron, which showed that Li is a suitable element for hydrogenation to B24N24.
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776Karachi, N.; Boshra, A.; Jadidi, S. DFT based insights into reactivity descriptors of encapsulated B24N24 nanocages. Struct. Chem. 2011, 22, 805– 809, DOI: 10.1007/s11224-011-9761-8776https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXos1Wmt7k%253D&md5=443231f781767eccbead74d5706bdb24DFT based insights into reactivity descriptors of encapsulated B24N24 nanocagesKarachi, Nima; Boshra, Asadollah; Jadidi, SiamakStructural Chemistry (2011), 22 (4), 805-809CODEN: STCHES; ISSN:1040-0400. (Springer)The authors present data on DFT(BLYP, B3LYP) geometries and reactivity indexes of B24N24, Li@B24N24, Na@B24N24, and K@B24N24 nanocages to be used in possible mol. engineering of endohedral BN-nanocages. They calcd. HOMO-LUMO band gap, chem. hardness, chem. potential, vertical electron affinity, and vertical ionization potential, as well as the global electrophilicity index, ω(I, A). The effect of MQZVP basis set on total electronic energy of the clusters was also studied.
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777Su, B.; Feng, X.; Guo, X.; Li, N. Polynitrogen clusters encapsulated inside B24N24 fullerene-like nanocages: Nanoscale high energy materials studied by density functional theory. Inorg. Chim. Acta 2017, 456, 128– 135, DOI: 10.1016/j.ica.2016.10.039777https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVahurbE&md5=7d4222902bd93bd9cd3920a8a8c168b9Polynitrogen clusters encapsulated inside B24N24 fullerene-like nanocages: Nanoscale high energy materials studied by density functional theorySu, Bo; Feng, Xiuli; Guo, Xueyong; Li, NanInorganica Chimica Acta (2017), 456 (), 128-135CODEN: ICHAA3; ISSN:0020-1693. (Elsevier B.V.)The complexes of polynitrogen clusters encapsulated inside o-B24N24 and s-B24N24 fullerene-like nanocages, Nn@o-B24N24 and Nn@s-B24N24, are predicted as nanoscale high energy materials and optimized at ωB97X-D theor. levels with the basis set of 6-31G(d). It is found that the max. of 10 N atoms can be encapsulated inside o-B24N24 and 9 N atoms inside s-B24N24. The encapsulated Nn clusters in Nn@o-B24N24 have the similar configurations for n = 1-5 and 7, and the different configurations for n = 6, 8 and 9 to those in Nn@s-B24N24. The total energy (ENn@B24N24) anal. and percentage relative elongation (ε = (R/R0 - 1) × 100%), all indicate that s-B24N24 is better for encapsulating the Nn clusters (n ≤ 5), and worse for the Nn clusters (n ≥ 6) than o-B24N24. The HOMO-LUMO energy gap of Nn@B24N24 generally show a gradual decrease with the increase of the no. of nitrogen atom of the encaged Nn in odd or even no., resp. And different from the pure B24N24, the electron d. patterns indicate that for complexes Nn@B24N24, the HOMO for n = 6-9 and the LUMO for n = 2-9 mainly conc. in the encaged Nn. The NBO anal., the Mulliken population anal. and the topol. anal. of the electron localization function (ELF) all demonstrate that there exist some covalent interactions between the encapsulated Nn clusters and the nanocages for the Nn@o-B24N24 (n = 7,9) and Nn@s-B24N24 (n = 5,7,9), while other complexes only have Van der Waals interactions.
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778Wang, Q.; Sun, Q.; Oku, T.; Kawazoe, Y. First-principles study of La–B36N36 cage. Phys. B 2003, 339, 105– 109, DOI: 10.1016/j.physb.2003.08.119778https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovFOjtLk%253D&md5=e01fa2eeaab0f4ab3cff689f257911a6First-principles study of La-B36N36 cageWang, Q.; Sun, Q.; Oku, T.; Kawazoe, Y.Physica B: Condensed Matter (Amsterdam, Netherlands) (2003), 339 (2-3), 105-109CODEN: PHYBE3; ISSN:0921-4526. (Elsevier Science B.V.)Based on the exptl. studies of La-B36N36 cluster (Takeo Oku et al., Diamond Rel. Mater. 11 (2002) 940), first principles calcns. using DFT-GGA and the projector-augmented wave methods were performed on La-B36N36 cluster. The structure was fully optimized. The encapsulation of a La atom inside the B36N36 cage is energetically favorable, although the interaction between the La atom and the cage is weak. In order to optimize the interactions with the cage, the La atom is shifted off the cage center. The HOMO-LUMO gap is much reduced by doping; the complex cage carries a magnetic moment of 1.0μB.
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779Nishiwaki, A.; Oku, T.; Suganuma, K. Atomic and electronic structures of endohedral B36N36 clusters with doping elements studied by molecular orbital calculations. Phys. B 2004, 349, 254– 259, DOI: 10.1016/j.physb.2004.03.308779https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXksF2qu7s%253D&md5=49d57b27c6a173d4dbc3ae126ccbc0bbAtomic and electronic structures of endohedral B36N36 clusters with doping elements studied by molecular orbital calculationsNishiwaki, Atsushi; Oku, Takeo; Suganuma, KatsuakiPhysica B: Condensed Matter (Amsterdam, Netherlands) (2004), 349 (1-4), 254-259CODEN: PHYBE3; ISSN:0921-4526. (Elsevier Science B.V.)At. and electronic structures of endohedral B36N36 clusters with doping elements were studied by MO calcns. Total energy calcn. showed that some elements stabilize and expand the B36N36 structure. Band gap energies of the B36N36 clusters were found to be reduced by introducing a metal atom inside the cluster, which indicates controllability of the energy gap.
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780Boshra, A.; Monajjemi, M.; Aghaie, M.; Aghaie, H. Density functional theory investigation of natural bond orbital population analysis and gauge-including atomic orbital NMR tensors of K@B36N36. J. Comput. Theor. Nanosci. 2010, 7, 1147– 1158, DOI: 10.1166/jctn.2010.1466780https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXlsFWlu7o%253D&md5=2bc9985bc0b391139057decd097c2825Density functional theory investigation of natural bond orbital population analysis and gauge-including atomic orbital NMR tensors of K@B36N36Boshra, Asadollah; Monajjemi, Majid; Aghaie, Mehran; Aghaie, HosseinJournal of Computational and Theoretical Nanoscience (2010), 7 (6), 1147-1158CODEN: JCTNAB; ISSN:1546-1955. (American Scientific Publishers)In this letter, D. Functional Theory (DFT) with hybrid functional B3LYP were employed to investigate several phys. and chem. properties of B36N36 and its encaged Potassium atom deriv. (K@B36N36). The quantum chem. computations in the framework of DFT for B36N36 cage and K@B36N36 has been performed using B3LYP level of theory supplemented with the std. 6-311G** basis set and utilizing the Gaussian 98 software package. The natural bond orbitals (NBO) calcns. were carried out using NBO 3.1 program as implemented in the Gaussian 98 package at the DFT/B3LYP level of theory and 6-31G* std. basis set. The encapsulation of Potassium atom into the B36N36 fullborene cage does not alter the cage chem. bonds considerably but makes HOMO-LUMO energy gap of the endohedral deriv. about 1.401 eV smaller than the computed value for the empty B36N36 cluster, also makes the system more stable because of its more favorable DFT mol. energy. The anal. of the natural bond orbital (NBO) suggests that there are about 0.18 electronic charge transferred from the encaged Potassium atom to the fullborene cluster. The occupancies of encapsulated cage NBOs showed a decrease and π bonds of bare B36N36 disappears introducing Potassium in to the cage. The donor-acceptor interactions between the cage and endo-Potassium atom were fully analyzed and predicted the mentioned interactions to be negligible. Some regional 2-electron delocalization obsd. between conjugated π bonds of B36N36 cage. Also GIAO nuclear magnetic shielding tensors of the atoms of the cages were computed and compared with each other.
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781Oliaey, A. R.; Boshra, A. DFT study of [Fe@B36N36]n+ (n = 2, 3) endohedral nanocages: Chemical reactivity, NBO analysis and thermochemistry. Phys. E 2013, 52, 136– 143, DOI: 10.1016/j.physe.2013.03.011781https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXosFyrtro%253D&md5=ce48ce9e6e7e193a9fd003d437e9af9bDFT study of [Fe@B36N36]n+ (n=2, 3) endohedral nanocages: Chemical reactivity, NBO analysis and thermochemistryOliaey, Ahmad reza; Boshra, AsadollahPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2013), 52 (), 136-143CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)In this study, the structures, vibrational stabilities, energy gaps of B36N36 nanocage and its two endohedral derivs., [Fe@B36N36]n+ (n=2, 3) were investigated via B3LYP hybrid functional of DFT. The transfer of charges and the inclusion energies of Fen+-encapsulated endohedrals were discussed as well. The detailed natural bond orbital (NBO) anal. revealed the nature of the hyperconjugative interactions of each nanocage. The NBO anal. specified an endohedral complex of Fe2+ with three nitrogen atoms of B36N36 while Fe3+ did not form such an endohedral complex. Also the global reactivity of the endohedrals based on NBO anal. was interpreted, and possible redox reactions of the studied nanocages were explained qual.
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782Batista, R. J.; Mazzoni, M. S.; Chacham, H. Boron nitride fullerene B36N36 doped with transition metal atoms: First-principles calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 035417, DOI: 10.1103/PhysRevB.75.035417782https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhs1eks7o%253D&md5=5022230b70448185739272dd97264a20Boron nitride fullerene B36N36 doped with transition metal atoms: First-principles calculationsBatista, Ronaldo J. C.; Mazzoni, Mario S. C.; Chacham, HelioPhysical Review B: Condensed Matter and Materials Physics (2007), 75 (3), 035417/1-035417/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We perform first-principles calcns. for the interaction of the transition metal atoms Fe, Co, and W, as well as the FeO mol., with the boron nitride fullerene B36N36. The stable structure of the atom-fullerene complexes may have the dopant atom either at the center of the cage or making covalent bonds with the fullerene wall, with similar total energies. We also find that the FeO mol. has a binding energy with the fullerene 2.5 eV larger than those of the transition metal atoms, and that it produces larger distortions in the cage. The electronic structure changes upon doping with the presence of several gap states. No magnetic moment is induced on the BN cage and, in general, the hybrid structures have the same magnetic moments as the isolated dopants.
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783Nigam, S.; Majumder, C. Magnetic needles encapsulated inside (BN)36 cage: Prediction of atomic, electronic, and magnetic structure from first principle calculations. Appl. Phys. Lett. 2007, 91, 223112, DOI: 10.1063/1.2815922783https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsVequ7rP&md5=efe1d4570ff464ed015622f8cac6d881Magnetic needles encapsulated inside (BN)36 cage: Prediction of atomic, electronic, and magnetic structure from first principle calculationsNigam, Sandeep; Majumder, ChiranjibApplied Physics Letters (2007), 91 (22), 223112/1-223112/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Using the 1st principle based d. functional theory formalism, the authors report the stability and structural aspects of small magnetic clusters inside chem. inert (BN)36 cage. Although the at. structures of small clusters showed significant changes due to the restrained imposed by the cage size, their stability improves inside the cage. Also, their magnetic structure remains almost unaltered in spite of being encaged. The implication of this work indicates that small magnetic particles can be protected inside the BN cage without losing their magnetic character for further applications.
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784Nigam, S.; Majumder, C. CO oxidation by BN–fullerene cage: Effect of impurity on the chemical reactivity. ACS Nano 2008, 2, 1422– 1428, DOI: 10.1021/nn8001455784https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXntVantrs%253D&md5=3faf2ddcd3d69537a53ed9f9f48fe45eCO Oxidation by BN-Fullerene Cage: Effect of Impurity on the Chemical ReactivityNigam, Sandeep; Majumder, ChiranjibACS Nano (2008), 2 (7), 1422-1428CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Using state of the art spin-polarized d. functional theory a chem. inert (BN)36 cluster can be activated by incorporating magnetic nanoparticles inside it. To illustrate this aspect the authors have calcd. the geometries and electronic structure of Fe(BN)36 and Fe4(BN)36 clusters, which showed the appearance of gap states localized on the impurity atoms. The reaction of O2 mols. with these clusters results in weak interaction and an elongation of the O-O bond. Further interaction of this complex species with an incoming CO mol. gives CO2. The reaction mechanism was studied via Langmuir-Hinshelwood and Elay-Rideal routes, and the min. energy path calcns. were performed using the elastic band method. These results have implications in designing novel materials based on metal nanoparticles for potential applications as industrial catalyst.
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785Nigam, S.; Kulshreshtha, S.; Majumder, C. Structural and magnetic isomers of M(BN)36 and M4(BN)36 clusters (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu): An ab initio density functional study. Phys. Rev. B: Condens. Matter Mater. Phys. 2008, 77, 075438, DOI: 10.1103/PhysRevB.77.075438785https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtFehu7c%253D&md5=8b4527ec41778ca7ad67b75e050e6fc9Structural and magnetic isomers of M(BN)36 and M4(BN)36 clusters (M=Ti,V,Cr,Mn,Fe,Co,Ni,Cu): An ab initio density functional studyNigam, Sandeep; Kulshreshtha, S. K.; Majumder, ChiranjibPhysical Review B: Condensed Matter and Materials Physics (2008), 77 (7), 075438/1-075438/10CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using the plane wave based pseudopotential method under the d. functional formalism, the geometry and electronic structures of M and M4 encaged (BN)36 clusters have been investigated, where M represents Ti, V, Cr, Mn, Fe, Co, Ni, and Cu atoms. The lowest energy structure of the M(BN)36 cluster shows that the impurity atom prefers to occupy either the center or off-center and close to the hexagonal ring of the cage. Geometry and electronic structures of M4 clusters have been calcd. in the bare state as well as inside the octahedral (BN)36 cluster. For free M4 clusters, except Cu4, which forms a planar rhombus structure, all other tetramer clusters adopt three dimensional bent rhombus or tetrahedron configuration. In sharp contrast, the equil. structure of M4 clusters inside the (BN)36 cage results in significant deformation in comparison to that in the free state. Unlike others, it is found that the stability of V4, Fe4, Co4, and Ni4 tetramers have been enhanced inside the cage. Importantly, these small clusters are found to retain their magnetic nature even after encaging them inside the (BN)36 cluster. In general, the magnetic moment of the M4 clusters are found to decrease inside the (BN)36 cage, except that for Cr4 cluster, which showed significant increase in the magnetic moment. The electronic d. of state anal. of these systems shows addnl. electronic states in the large gap of (BN)36 cluster originated by the M atoms or M4 clusters.
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786Wen, S.-H.; Deng, W.-Q.; Han, K.-L. Endohedral BN metallofullerene M@B36N36 complex as promising hydrogen storage materials. J. Phys. Chem. C 2008, 112, 12195– 12200, DOI: 10.1021/jp801893f786https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosFKlsLs%253D&md5=1bec8666d8edc87b4cd193dae1ce2413Endohedral BN Metallofullerene M@B36N36 Complex As Promising Hydrogen Storage MaterialsWen, Shu-Hao; Deng, Wei-Qiao; Han, Ke-LiJournal of Physical Chemistry C (2008), 112 (32), 12195-12200CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)By using first-principles calcns. within the frame of the d. functional theory, we have investigated the encapsulation of metal atoms (Li, Na, Be, Mg, and Ti) in a B36N36 cage and the effects of endohedral metal atoms on hydrogen storage in the B36N36. The calcns. showed that the chemisorption energies of the H on the B36N36 cage shell can be modified by the charged endohedral metal atom in the B36N36 cage, due to the electrostatic interaction and polarization of the cage electrons. Endohedral metal atoms also exert influences on H2 mols. residing inside the B36N36 cage. For Ti@B36N36, we predict a high hydrogen content (8 wt %) structure with a full H coverage on the outer cage shell and with the Kubas complex in the inner cavity.
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787Liang, W.; Jia, J.; Lv, J.; Wu, H. Electronic structure, stability and magnetic properties of small M1–4 (M = Fe, Co, Ni) clusters encapsulated inside a (BN)48 cage. Chem. Phys. Lett. 2015, 622, 57– 62, DOI: 10.1016/j.cplett.2014.12.020787https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht1Ogsb0%253D&md5=70db4080388ad0ef114a9036d3a4844eElectronic structure, stability and magnetic properties of small M1-4(M = Fe, Co, Ni) clusters encapsulated inside a (BN)48 cageLiang, Wenjuan; Jia, Jianfeng; Lv, Jin; Wu, HaishunChemical Physics Letters (2015), 622 (), 57-62CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The geometrical structure and magnetic properties of M1-4(M = Fe, Co and Ni) clusters within a (BN)48 cage were calcd. at the BPW91/LanL2DZ level. The small M1-4 clusters generally prefer an off-centered position near the hexagonal rings in the (BN)48 cages. The (BN)48 cages can increase the stability of these small magnetic clusters while protecting their magnetic nature.
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788Liang, W.; Jia, J.; Lv, J.; Wu, H. Density functional theory study of Mo-doped M@(BN)48 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) clusters. J. Mol. Struct. 2016, 1108, 92– 95, DOI: 10.1016/j.molstruc.2015.11.057788https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVClsbfF&md5=245285da113db661604a14bc2fd3194fDensity functional theory study of Mo-doped M@(BN)48 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) clustersLiang, Wenjuan; Jia, Jianfeng; Lv, Jin; Wu, HaishunJournal of Molecular Structure (2016), 1108 (), 92-95CODEN: JMOSB4; ISSN:0022-2860. (Elsevier B.V.)The structure and magnetic properties of Mo-doped M@(BN)48 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) clusters were calcd. at BPW91/LanL2DZ level. The magnetic nature of the clusters M@(BN)48 significantly changed when doping with Mo atom, except for Co@(BN)48. Only the magnetic moment for the CrMo@(BN)48 cluster was decreased to zero. Thus, M@(BN)48 clusters can be selected as the model system to detect Mo atom by the change of the magnetic moment.
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789Kumar, V.; Kawazoe, Y. Hydrogenated caged clusters of Si, Ge, and Sn and their endohedral doping with atoms: Ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 155425, DOI: 10.1103/PhysRevB.75.155425789https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXltVShu7Y%253D&md5=074eaede29f12d54352808f86939b7d6Hydrogenated caged clusters of Si, Ge, and Sn and their endohedral doping with atoms: Ab initio calculationsKumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2007), 75 (15), 155425/1-155425/11CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The stability was studied of hydrogenated empty cages XnHn with X = Si, Ge, and Sn, and n = 8, 10, 12, 14, 16, 18, 20, 24, and 28 using the DFT-GGA and ultrasoft-pseudopotential plane-wave methods. All these cages have large HOMO-LUMO gaps. The HOMO-LUMO gap for Ge cages was found to be even larger than the values for Si cages, though in bulk Ge has a smaller band gap than Si. Cages with n = 16 and 20 were found to be particularly stable in the form of fullerene structures. The bonding in the dodecahedral X20H20 cage is very close to sp3 type and it leads to the highest stability of this cage with perfect icosahedral symmetry. Endohedral doping of the empty cages such as SinHn (n = 10-28), with different guest atoms shows that doping can be used to manipulate the HOMO-LUMO gap with the possibility of varying their optical properties as well as to prep. species with large magnetic moments. Depending upon the guest atom, the character of the HOMO and the LUMO states and their origins either from the cage or the guest atom changes. This could lead to their applications in sensors. In contrast to the metal-encapsulated silicon-caged clusters, the embedding energy of the guest atom in the hydrogenated silicon fullerenes is small in most cases due to the weak interactions with the cage and therefore these slaved guest atoms can keep their at. properties to a large extent. We find that atoms with closed electronic shell configurations such as Ca, Ba,... generally occupy the center of the cage. However, Be and other open electronic shell atoms tend to drift towards the wall of the cage. Doping with halogens such as iodine and alkalis such as Na can be used to produce, resp. hole and electron doping while transition-metal atoms such as V, Cr, Mn, and Fe were shown to produce at.-like magnetic moments in many cases. In most of these cases the HOMO-LUMO gap becomes small because the guest atom orbital(s) are only partially occupied. However, for Ni and Zn the HOMO-LUMO gap is large as the hybridized d orbitals become fully occupied. An interesting finding was that the endohedral doping can lead to a higher-energy undoped cage isomer to become the lowest-energy doped isomer. Implications of this result for endohedral fullerenes of carbon are also discussed.
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790Bahramy, M. S.; Kumar, V.; Kawazoe, Y. First-principles calculations of hyperfine structure in M-doped Si16H16 fullerene cages (M = Cr, Mn, and Fe). Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 79, 235443, DOI: 10.1103/PhysRevB.79.235443790https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXotFKqu70%253D&md5=d9f4d04341f65a90f9f669e9d405eb5dFirst-principles calculations of hyperfine structure in M-doped Si16H16 fullerene cages (M=Cr, Mn, and Fe)Bahramy, Mohammad Saeed; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2009), 79 (23), 235443/1-235443/7CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We study magnetism and hyperfine structure in Si16H16 fullerenes endohedrally doped with a transition-metal atom M=Cr, Mn, and Fe using d. functional theory calcns. In all cases the endohedral fullerene maintains the same magnetic moment as in a free M atom and it is mainly localized on M with partial redistribution on the Si16H16 cage. However, a comparison between the isotropic hyperfine parameter Aiso of M dopants with that of free M atoms reveals that the electronic wave function at the nucleus of Mn and Fe undergo a significant change both quant. and qual. as they become doped inside Si16H16 cage, while for Cr it remains nearly the same. The endohedral doping of Mn and Fe atoms increases the value of the spin d. at the nucleus of the M atom, ρs(RM) and correspondingly, the value of Aiso. Analyzing the trend of the core spin polarization induced by the singly occupied MOs (SOMOs), it is shown that the increase in the value of Aiso for Mn and Fe atoms comes directly from an increase in the contribution of SOMOs to ρs(RM) and indirectly from hybridization of 3d orbitals of the dopants with the s- and p-like orbitals of the cage. The latter results in a decrease in the spin-polarization of the core 2s and 3s orbitals so that they less effectively contribute to ρs(RM). These results are likely to have wider applicability and could offer a way to identify endohedral doping.
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791Zhao, Y.; Kim, Y.-H.; Dillon, A.; Heben, M.; Zhang, S. Hydrogen storage in novel organometallic buckyballs. Phys. Rev. Lett. 2005, 94, 155504, DOI: 10.1103/PhysRevLett.94.155504791https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjsFGrsb0%253D&md5=fa6661402f3f7f2e2f64a9bc3c46f777Hydrogen Storage in Novel Organometallic BuckyballsZhao, Yufeng; Kim, Yong-Hyun; Dillon, A. C.; Heben, M. J.; Zhang, S. B.Physical Review Letters (2005), 94 (15), 155504/1-155504/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Transition metal (TM) atoms bound to fullerenes are proposed as adsorbents for high d., room temp., ambient pressure storage of H. C60 or C48B12 disperses TMs by charge transfer interactions to produce stable organometallic buckyballs (OBBs). A Sc OBB can bind as many as 11 H atoms per TM, 10 of which are as dihydrogen that can be adsorbed and desorbed reversibly. In this case the calcd. binding energy is ∼0.3 eV/H2, which is ideal for hydrogen storage in vehicles. The theor. max. retrievable H2 storage d. is ∼9%.
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792Yildirim, T.; Ciraci, S. Titanium-decorated carbon nanotubes as a potential high-capacity hydrogen storage medium. Phys. Rev. Lett. 2005, 94, 175501, DOI: 10.1103/PhysRevLett.94.175501792https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvF2nsrw%253D&md5=d422830119d37719d2e29e7729e726fdTitanium-decorated carbon nanotubes as a potential high-capacity hydrogen storage mediumYildirim, T.; Ciraci, S.Physical Review Letters (2005), 94 (17), 175501/1-175501/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)We report a 1st-principles study, which demonstrates that a single Ti atom coated on a single-walled nanotube (SWNT) binds up to four H mols. The first H2 adsorption is dissociative with no energy barrier while the other three adsorptions are mol. with significantly elongated H-H bonds. At high Ti coverage we show that a SWNT can strongly adsorb up to 8 wt. % hydrogen. These results advance our fundamental understanding of dissociative adsorption of hydrogen in nanostructures and suggest new routes to better storage and catalyst materials.
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793Liang, W.; Jia, J.; Lv, J.; Wu, H. Electronic structure, stability and magnetic properties of small M1–2Cr (M= Fe, Co, and Ni) alloy encapsulated inside a (BN)48 cage. Phys. Lett. A 2015, 379, 1715– 1721, DOI: 10.1016/j.physleta.2015.04.037793https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnvFequ70%253D&md5=fa68ae2225509e896e4c93278ea1cff2Electronic structure, stability and magnetic properties of small M1-2Cr (M = Fe, Co, and Ni) alloy encapsulated inside a (BN)48 cageLiang, Wenjuan; Jia, Jianfeng; Lv, Jin; Wu, HaishunPhysics Letters A (2015), 379 (30-31), 1715-1721CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)The geometrical structure and magnetic properties of M1-2Cr (M = Fe, Co, and Ni) alloy clusters inside a (BN)48 cage were calcd. at the BPW91/LANL2DZ level of theory. The doping with Cr significantly changed the magnetic properties of the transition-metal clusters. When M1-2Cr alloys were placed inside a (BN)48 cage, the alloy clusters interacted strongly with the cage, and the M1-2Cr@(BN)48 clusters showed high stability. Moreover, Cr-doped magnetic metal clusters preferably occupied positions off-center and near the hexagonal rings of (BN)48 cages. Thus, the (BN)48 cages can be used to increase the stability of M1-2Cr alloys, and retain their magnetic nature, except for CoCr and Ni2Cr clusters.
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794Burnin, A.; BelBruno, J. J. ZnnSm+ cluster production by laser ablation. Chem. Phys. Lett. 2002, 362, 341– 348, DOI: 10.1016/S0009-2614(02)01105-3794https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmtlWgtrs%253D&md5=4c915254988186e46941f1975efa1c4aZnnS+m cluster production by laser ablationBurnin, Andrei; BelBruno, Joseph J.Chemical Physics Letters (2002), 362 (3,4), 341-348CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)Laser ablation of ZnS or mixts. of elemental Zn and S was used to produce clusters. Mass spectrometric detection was used to identify the products. Regardless of the compn. of the ablation sample, mass spectra were dominated by mixed cluster ions. The mass peak corresponding to Zn13S+13 was present in an abundance much greater than its neighbor ions, indicating that the geometry of this particular cluster confers a special stability. The mass spectra of the analogous ZnO clusters did not exhibit magic nos. Structure calcns. were employed to provide a preliminary est. of the possible geometries of this cluster.
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795Kasuya, A.; Sivamohan, R.; Barnakov, Y. A.; Dmitruk, I. M.; Nirasawa, T.; Romanyuk, V. R.; Kumar, V.; Mamykin, S. V.; Tohji, K.; Jeyadevan, B. Ultra-stable nanoparticles of CdSe revealed from mass spectrometry. Nat. Mater. 2004, 3, 99– 102, DOI: 10.1038/nmat1056795https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXoslWqtg%253D%253D&md5=6f2c1cb85b546b484e1dbc5c4ad98799Ultra-stable nanoparticles of CdSe revealed from mass spectrometryKasuya, Atsuo; Sivamohan, Rajaratnam; Barnakov, Yurii A.; Dmitruk, Igor M.; Nirasawa, Takashi; Romanyuk, Volodymyr R.; Kumar, Vijay; Mamykin, Sergiy V.; Tohji, Kazuyuki; Jeyadevan, Balachandran; Shinoda, Kozo; Kudo, Toshiji; Terasaki, Osamu; Liu, Zheng; Belosludov, Rodion V.; Sundararajan, Vijayaraghavan; Kawazoe, YoshiyukiNature Materials (2004), 3 (2), 99-102CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Nanoparticles under a few nanometers in size have structures and material functions that differ from the bulk because of their distinct geometrical shapes and strong quantum confinement. These qualities could lead to unique device applications. The authors' mass spectral anal. of CdSe nanoparticles reveals that (CdSe)33 and (CdSe)34 are extremely stable: with a simple soln. method, they grow in preference to any other chem. compns. to produce macroscopic quantities. First-principles calcns. predict that these are puckered (CdSe)28-cages, with four- and six-membered rings based on the highly sym. octahedral analogs of fullerenes, accommodating either (CdSe)5 or (CdSe)6 inside to form a three-dimensional network with essentially heteropolar sp3-bonding. This is in accordance with the authors' x-ray and optical analyses. The authors found similar mass spectra and at. structures in CdS, CdTe, ZnS and ZnSe, demonstrating that mass-specified and macroscopically produced nanoparticles, which were practically limited so far to elemental C, can now be extended to a vast variety of compd. systems.
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796Kasuya, A.; Noda, Y.; Dmitruk, I.; Romanyuk, V.; Barnakov, Y.; Tohji, K.; Kumar, V.; Belosludov, R.; Kawazoe, Y.; Ohuchi, N. Stoichiometric and ultra-stable nanoparticles of II-VI compound semiconductors. Eur. Phys. J. D 2005, 34, 39– 41, DOI: 10.1140/epjd/e2005-00114-9796https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtFOru7c%253D&md5=9b7722230bf9981793fad69ccd7750c1Stoichiometric and ultra-stable nanoparticles of II-VI compound semiconductorsKasuya, A.; Noda, Y.; Dmitruk, I.; Romanyuk, V.; Barnakov, Y.; Tohji, K.; Kumar, V.; Belosludov, R.; Kawazoe, Y.; Ohuchi, N.European Physical Journal D: Atomic, Molecular and Optical Physics (2005), 34 (1-3), 39-41CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)Nanoparticles of (CdSe)n are found extremely stable at n = 33 and 34 with structures distinctively different from the bulk fragments. They grow exclusively in large amt. with a simple soln. method. The diam. is detd. as 1.5 nm. Such ultra-stable nanoparticles had been predicted both theor. and exptl. after the discovery of C fullerenes, but not been produced macroscopically in any other element or compd. system. First-principles calcns. predict that the structures of (CdSe)33 and (CdSe)34 are puckered (CdSe)28-cages accommodating resp. (CdSe)5 an (CdSe)6 inside to form a three-dimensional network of essentially hetero-polar sp3-bonding.
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797Kukreja, L.; Rohlfing, A.; Misra, P.; Hillenkamp, F.; Dreisewerd, K. Cluster formation in UV laser ablation plumes of ZnSe and ZnO studied by time-of-flight mass spectrometry. Appl. Phys. A: Mater. Sci. Process. 2004, 78, 641– 644, DOI: 10.1007/s00339-003-2272-8797https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhsFyktr8%253D&md5=002c008ce81d6f6ce6aec3dc320f71a0Cluster formation in UV laser ablation plumes of ZnSe and ZnO studied by time-of-flight mass spectrometryKukreja, L. M.; Rohlfing, A.; Misra, P.; Hillenkamp, F.; Dreisewerd, K.Applied Physics A: Materials Science & Processing (2004), 78 (5), 641-644CODEN: APAMFC; ISSN:0947-8396. (Springer-Verlag)The compn. of nitrogen laser (wavelength 337 nm, pulse width 3 ns) induced ablation plumes from ZnSe and ZnO targets was studied at different laser fluences using a time-of-flight mass spectrometer. In the case of ZnSe, abundant ion signals corresponding to Se and ZnSe clusters, some of which were Se-rich, were detected with fluence-dependent distributions. At a laser fluence of 1250 J m-2, clusters with elevated intensity were obsd. at sizes of 6, 13, 19, 23 and 33 ZnSe mols. ( magic nos.), which match quite well with the earlier observation by others of magic nos. of chem. similar ZnS produced by a conventional vaporization and quenching scheme. In the case of ZnO, we detected the presence of at. Zn and mol. species of ZnO, as well as a series of (ZnO)n-type clusters with fluence-dependent distributions. Unlike the case of ZnSe, no magic nos. were obsd. for ZnO.
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798Hamad, S.; Catlow, C. R. A.; Spano, E.; Matxain, J. M.; Ugalde, J. M. Structure and properties of ZnS nanoclusters. J. Phys. Chem. B 2005, 109, 2703– 2709, DOI: 10.1021/jp0465940798https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtVSqtA%253D%253D&md5=cb1f16bd51f3387b2b467cb54352786cStructure and Properties of ZnS NanoclustersHamad, Said; Catlow, C. Richard A.; Spano, Eleonora; Matxain, Jon M.; Ugalde, Jesus M.Journal of Physical Chemistry B (2005), 109 (7), 2703-2709CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)Earlier studies have shown that the most stable structures for (ZnS)n clusters with n = 10-47 are hollow polyhedral clusters ("bubbles"). We report a detailed study of larger clusters, where n = 50, 60, 70, and 80, for which onionlike or "double bubble" structures are predicted. We report calcns. of the vibrational spectra and the electronic structure of bubble and double bubble clusters, which may assist in their exptl. identification.
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799Matxain, J. M.; Eriksson, L. A.; Formoso, E.; Piris, M.; Ugalde, J. M. Endohedral (X@ZniSi)i=4-160,± nanoclusters, X = Li, Na, K, Cl, Br. J. Phys. Chem. C 2007, 111, 3560– 3565, DOI: 10.1021/jp0668697799https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsFOktbY%253D&md5=b9a39a88ee2f1dfd5d2bd643f9e313eeEndohedral (X@ZniSi)1=4-160,± Nanoclusters, X = Li, Na, K, Cl, BrMatxain, Jon M.; Eriksson, Leif A.; Formoso, Elena; Piris, Mario; Ugalde, Jesus M.Journal of Physical Chemistry C (2007), 111 (9), 3560-3565CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Endohedral (X@ZniSi)q (q = -1, 0, 1) structures were calcd. using the DFT-B3LYP method. In these structures, the X atoms are trapped inside previously characterized spheroid hollow structures with pos. charged Zn atoms and neg. charged S atoms. Although the radii of all atoms are similar, Zn atoms are located more inside the structure. The alkali metals are found to be trapped inside a larger no. of spheroid structures than the halogens. The parameters detg. the stability of the endohedral structures are the charge and size of the trapped atom, along with the sphericity of the cluster.
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800Poggio, S.; Wang, B.; Gibson, U. J.; BelBruno, J. J. Properties of transition metal substituted zinc sulfide hexamers and dodecamers. Phys. Chem. Chem. Phys. 2015, 17, 14208– 14214, DOI: 10.1039/C5CP00574D800https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnsVaqs7Y%253D&md5=3353d0a7acc67e0194c6496aadd70a99Properties of transition metal substituted zinc sulfide hexamers and dodecamersPoggio, Stefano; Wang, Brendan; Gibson, Ursula J.; BelBruno, Joseph J.Physical Chemistry Chemical Physics (2015), 17 (21), 14208-14214CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)D. functional theory was used to study the structural and electronic properties of endohedrally- and substitutionally-doped Zn6S6 and Zn12S12 clusters with first-row transition metal atoms. Generally, the lowest energy electronic state of the cluster is that with the max. multiplicity (Ti and Cr are exceptions). Substitutionally-doped clusters have greater binding energies (per atom) for both cluster sizes, providing an indication that similar doping will be preferred in the bulk material as well. The results are relevant to thin films of doped ZnS in which cluster formation is likely.
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801Matxain, J. M.; Formoso, E.; Mercero, J. M.; Piris, M.; Lopez, X.; Ugalde, J. M. Magnetic endohedral transition-metal-doped semiconduncting-nanoclusters. Chem. - Eur. J. 2008, 14, 8547– 8554, DOI: 10.1002/chem.200800376801https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht1OgsbvJ&md5=539993d1c35f80204247e078b08bf213Magnetic endohedral transition-metal-doped semiconducting nanoclustersMatxain, Jon M.; Formoso, Elena; Mercero, Jose M.; Piris, Mario; Lopez, Xabier; Ugalde, Jesus M.Chemistry - A European Journal (2008), 14 (28), 8547-8554CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Endohedral 1st-row transition-metal-doped TM@ZniSi nanoclusters, in which TM stands for the 1st-row transition-metals from Sc to Zn, and i = 12, 16, were characterized. In these structures the dopant metals are trapped inside spheroidal hollow semiconducting nanoclusters. Some of the transition metals are trapped in the center of mass of the cluster, whereas others are displaced from that center, leading to structures in which the transition metals display a complex dynamical behavior upon encapsulation. This fact was confirmed by quantum mol. dynamics calcns., which further confirmed the thermal stability of endohedral compds. In the endohedrally-doped nanoclusters in which the transition-metal atom sits on the center of mass, the host hollow cluster structure remains undistorted after dopant encapsulation. Conversely, if the encapsulated transition-metal atom is displaced from the center of mass, the host hollow cluster structure suffers a very tiny distortion. Addnl., there is negligible charge transfer between the dopant transition-metal atom and its hollow cluster host and, after encapsulation, the spin densities remain localized on the transition-metal atom. This allows for the at.-like behavior of the trapped transition-metal atom, which gives rise to their at.-like magnetic properties. The encapsulation free energies are neg., suggesting that these compds. are thermodynamically stable.
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802Jimenez-Izal, E.; Matxain, J. M.; Piris, M.; Ugalde, J. M. Thermal stability of endohedral first-row transition-metal TM@ZniSi structures, i = 12, 16. J. Phys. Chem. C 2011, 115, 7829– 7835, DOI: 10.1021/jp108640w802https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXktFenurc%253D&md5=3ee4acf29e7b00ff74fc9a3843cab2e2Thermal Stability of Endohedral First-Row Transition-Metal TM@ZniSi Structures, i = 12, 16Jimenez-Izal, Elisa; Matxain, Jon M.; Piris, Mario; Ugalde, Jesus M.Journal of Physical Chemistry C (2011), 115 (16), 7829-7835CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The thermal stability was studied of first-row transition-metal-doped TM@ZniSi nanoclusters for the two lowest-lying spin states of each metal using DFT-GGA methods (TM stands for the first-row transition metals from Sc to Zn; i = 12, 16). These structures were previously characterized by Matxain et al. The metal atom can move toward the surface of the nanocluster forming the so-called surface-doped structure. The relative energies of two isomers were calcd. We also characterized the transition states connecting both isomers and the energy barriers needed to move from one to another in order to predict the thermal stability of the endohedral compds. These values were further used to predict the lifetimes of the endohedrally doped nanoclusters. Most of the lifetimes were predicted to be very small, although most of them are large enough for exptl. detection. The lifetimes of Zn@Zn12S12 and Zn@Zn16S16 are very large.
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803Jimenez-Izal, E.; Matxain, J.; Piris, M.; Ugalde, J. Second-row transition-metal doping of (ZniSi), i = 12, 16 nanoclusters: Structural and magnetic properties. Computation 2013, 1, 31– 45, DOI: 10.3390/computation1030031There is no corresponding record for this reference.
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804Chen, H.; Shi, D.; Qi, J.; Wang, B. Structure, electronic and magnetic properties of Cr-doped (ZnS)12 clusters: A first-principles study. Phys. Lett. A 2010, 374, 4133– 4139, DOI: 10.1016/j.physleta.2010.08.030804https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFWiurfP&md5=d63bbb9d63416e0cf4110704433e3e15Structure, electronic and magnetic properties of Cr-doped (ZnS)12 clusters: A first-principles studyChen, Hongxia; Shi, Daning; Qi, Jingshan; Wang, BaolinPhysics Letters A (2010), 374 (40), 4133-4139CODEN: PYLAAG; ISSN:0375-9601. (Elsevier B.V.)We have studied the structural, electronic, and magnetic properties of (ZnS)12 clusters doped with one (monodoped) and two (bidoped) Cr atoms in terms of a first-principles method. Substitutional, exohedral, and endohedral doping are considered. The substitutional isomer is found to be most favorable in energy for monodoped clusters, while the exohedral isomers are found to be most favorable for bidoped clusters. The magnetic coupling between the Cr atoms is mainly governed by the competition between direct Cr-Cr antiferromagnetic (AFM) interaction and the ferromagnetic (FM) interaction between two Cr atoms via S atom due to strong p-d hybridization. Finally, we show that the exohedral bidoped (ZnS)12 clusters favor the FM state, which has potential applications in nanoscale quantum devices.
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805Chen, H.; Shi, D.; Qi, J.; Wang, B. First-principles study on the structure, electronic, and magnetic properties of Mn-doped (ZnS)12 clusters. Phys. E 2010, 43, 117– 124, DOI: 10.1016/j.physe.2010.06.027805https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVyhurbM&md5=1015d745e7b8da9aad170e652a2ba6edFirst-principles study on the structure, electronic, and magnetic properties of Mn-doped (ZnS)12 clustersChen, Hongxia; Shi, Daning; Qi, Jingshan; Wang, BaolinPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2010), 43 (1), 117-124CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)A first-principles d. functional investigation has been performed to evaluate the structural, electronic, and magnetic properties of (ZnS)12 clusters doped with one (monodoped) and two (bidoped) Mn atoms. Substitutional, endohedral, and exohedral doping are considered. The substitutional isomers are found to be most favorable in energy for both monodoped and bidoped clusters. For the optimized isomers of the monodoped case, the doping-induced changes of the bond lengths generally are less than 0.03 Å. The total magnetic moment is independent of at. configuration. For the bidoped case, we find that the magnetic coupling between Mn atoms in host cluster depends on their local environment. The cohesion of substitutional bidoped isomers is found to be more sensitive to the magnetic coupling, while the exohedral ones are more sensitive to the chem. bonding. Most importantly, we demonstrate that the endohedral bidoped (ZnS)12 cluster favors the ferromagnetic state, which has potential applications in nanoscale quantum devices.
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806Chen, H.; Shi, D.; Qi, J.; Wang, B. First-principles study on the magnetic properties of transition-metal atoms doped (ZnS)12 cluster. J. Magn. Magn. Mater. 2011, 323, 781– 788, DOI: 10.1016/j.jmmm.2010.10.044806https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhs1SrtrnE&md5=dde285d22c466962c4c576265db0bb0cFirst-principles study on the magnetic properties of transition-metal atoms doped (ZnS)12 clusterChen, Hongxia; Shi, Daning; Qi, Jingshan; Wang, BaolinJournal of Magnetism and Magnetic Materials (2011), 323 (6), 781-788CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)A 1st-principles d. functional study was performed to evaluate the structural, electronic, and magnetic properties of (ZnS)12 doped with one or two transition-metal (TM) atoms (Fe, Co, and Ni). Substitutional- and interstitial-doping are considered. The substitutional isomers are most favorable for Fe-doped clusters, while the interstitial isomers are most favorable for Co- and Ni-doped clusters. Magnetic coupling between the TM atoms at the nearest neighbor position is mainly governed by the competition between direct ferromagnetic and antiferromagnetic interactions between two TM atoms via the S atom due to strong p-d hybridization. The coupling is short-ranged. Most importantly, the Fe and Ni endohedral bi-doped (ZnS)12 clusters favor the ferromagnetic state, which has potential applications in nanoscale quantum devices.
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807Zhang, D.; Chen, L.; Zhang, J.; Miao, X. Theoretical investigation of structural and magnetic properties of ZnnSen (n = 6–13) nanoclusters doped with manganese atoms. J. Am. Ceram. Soc. 2011, 94, 759– 764, DOI: 10.1111/j.1551-2916.2010.04125.x807https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXksFOktbs%253D&md5=8914cd24968870807b5cc47f937cc74bTheoretical investigation of structural and magnetic properties of ZnnSen (n = 6-13) nanoclusters doped with manganese atomsZhang, Daoli; Chen, Liangyan; Zhang, Jianbing; Miao, XiangshuiJournal of the American Ceramic Society (2011), 94 (3), 759-764CODEN: JACTAW; ISSN:0002-7820. (Wiley-Blackwell)With the generalized gradient approxn. in first principle all-electron calcns., the lowest energy structures of ZnnSen (n = 6-13) nanoclusters were obtained as the pristine clusters. A no. of configurations and structural isomers of ZnnSen (n = 6-13) nanoclusters doped with single and two Mn atoms were used to investigate the structural and magnetic properties of manganese-doped ZnnSen (n = 6-13) nanoclusters. It arrives at a conclusion that Mn doping does not change the size-dependent oscillating behavior in second-order energy difference of ZnnSen (n = 6-13) nanoclusters, but leads to the decrease of energy gap between LUMO and the HUMO. Energy arguments indicate that Mn atoms prefer to substitute Zn atoms in Mn-doped ZnnSen (n = 6-13) nanoclusters. Owing the Mn-Mn short-ranged super-exchange mechanism, Mn atoms favor to locate at adjacent Zn atom sites in antiferromagnetic states of ZnnSen nanoclusters doped with two Mn atoms.
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808Yadav, M. K.; Sanyal, B.; Mookerjee, A. Structural, electronic and magnetic properties of Cr-doped (ZnTe)12 clusters. J. Magn. Magn. Mater. 2009, 321, 235– 240, DOI: 10.1016/j.jmmm.2008.08.092There is no corresponding record for this reference.
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809Ghosh, S.; Sanyal, B.; Das, G. Structural, electronic and magnetic properties of Cr-doped Cd12S12 clusters: A density functional investigation. J. Magn. Magn. Mater. 2010, 322, 734– 742, DOI: 10.1016/j.jmmm.2009.10.051809https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjtVKhtw%253D%253D&md5=19f1e9537819e4d8caec661cfbd07b28Structural, electronic and magnetic properties of Cr-doped Cd12S12 clusters: A density functional investigationGhosh, S.; Sanyal, B.; Das, G. P.Journal of Magnetism and Magnetic Materials (2010), 322 (6), 734-742CODEN: JMMMDC; ISSN:0304-8853. (Elsevier B.V.)We have carried out first-principles d. functional investigation of Cd12S12 cluster doped with one (monodoped) and two (bidoped) Cr-atoms, to explore the manifestation of novel magnetism in this family of stable II-VI semiconducting clusters. Different types of possible configurations of the dopant e.g. substitutional, exohedral, endohedral and substitutional-exohedral have been considered. Both for monodoped and bidoped clusters, substitutional doping corresponds to the ground state. In case of bidoped clusters, the coupling is found to be short-ranged, that depends on the Cr-Cr sepn. and the local environment. The main competing factors stabilizing ferromagnetic (FM) state in this class of doped nanoclusters are: (a) the FM interaction between two Cr atoms via S atom due to strong p-d hybridization and (b) the short range Cr-Cr direct antiferromagnetic (AFM) interaction. When addnl. hole is introduced in the system by substituting S with P, in substitutional bidoped clusters, FM state is found to be the ground sate.
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810Jimenez-Izal, E.; Matxain, J. M.; Piris, M.; Ugalde, J. M. Structure and stability of the endohedrally doped (X@CdiSi)i=4, 9, 12, 15, 16q=0,±1, X = Na, K, Cl, Br, nanoclusters. J. Phys. Chem. C 2010, 114, 2476– 2483, DOI: 10.1021/jp909357c810https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFams7w%253D&md5=453e119b3df2cfa9e07b9717d4901042Structure and Stability of the Endohedrally Doped (X@CdiSi)i=4,9,12,15,16q=0,±1, X = Na, K, Cl, Br, NanoclustersJimenez-Izal, Elisa; Matxain, Jon M.; Piris, Mario; Ugalde, Jesus M.Journal of Physical Chemistry C (2010), 114 (6), 2476-2483CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The endohedral title structures were studied by the DFT-B3LYP method. These nanoclusters were chosen because of their high sphericity, which was known to be one of the parameters detg. the stability of the endohedral nanoclusters, along with the charge and size of the guest atom. In these structures, the atoms are trapped inside previously characterized spheroid hollow structures with pos. charged Cd atoms and neg. charged S atoms. Moreover, although the radii of all atoms are similar, Cd atoms are located more inside the structure. For alkali metals, neutral and cationic endohedral compds. were characterized and, for halogens, neutral and anionic nanoclusters were studied. Some of these guest atoms are trapped in the center of mass of the cluster, while others are displaced from that center leading to structures where the guest atom shows a complex dynamical behavior. This fact was confirmed by quantum mol. dynamics calcns., which further confirmed the thermal stability of these endohedral compds.
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811Poggio, S.; King, J.; BelBruno, J. Properties of transition metal doped cadmium sulfide hexamers and dodecamers. Chem. Phys. Lett. 2015, 640, 106– 111, DOI: 10.1016/j.cplett.2015.10.007811https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12jurzM&md5=9c96e3c11eff34d9ae0fd76a21d403cdProperties of transition metal doped cadmium sulfide hexamers and dodecamersPoggio, Stefano; King, Jonathan; BelBruno, JosephChemical Physics Letters (2015), 640 (), 106-111CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)The electronic and geometrical properties of endohedrally and substitutionally doped Cd6S6 and Cd12S12 clusters were analyzed by means of DFT-PBE method. The results are compared to those of ZnS clusters of the same size. There is a clear correlation between CdS and ZnS when doped with the same element due to the chem. interaction between the dopant and its host. This is particularly evident from endohedrally doped Cd6S6. The change in properties across the 3d series in doped CdS clusters is not as great as in ZnS clusters.
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812Shevlin, S.; Guo, Z.; Van Dam, H.; Sherwood, P.; Catlow, C. A.; Sokol, A.; Woodley, S. Structure, optical properties and defects in nitride (III–V) nanoscale cage clusters. Phys. Chem. Chem. Phys. 2008, 10, 1944– 1959, DOI: 10.1039/b719838h812https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjvVentL8%253D&md5=a07ded99e7741054200a28b49957b1e9Structure, optical properties and defects in nitride (III-V) nanoscale cage clustersShevlin, S. A.; Guo, Z. X.; van Dam, H. J. J.; Sherwood, P.; Catlow, C. R. A.; Sokol, A. A.; Woodley, S. M.Physical Chemistry Chemical Physics (2008), 10 (14), 1944-1959CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)DFT-GGA calcns. are reported on cage structured BN, AlN, GaN and InN sub- and low nanosize stoichiometric clusters, including two octahedral families of Td and Th symmetry. The structures and energetics are detd., and we observe that BN clusters in particular show high stability with respect to the bulk phase. The cluster formation energy is demonstrated to include a const. term that we attribute to the curvature energy and the formation of six tetragonal defects. The (BN)60 onion double-bubble structure was found to be particularly unstable. In contrast, similar or greater stability was found for double and single shell cages for the other nitrides. The optical absorption spectra have been first characterized by the one-electron Kohn-Sham orbital energies for all compds., after which we concd. on BN where we employed a recently developed time-dependent DFT approach. The one-electron band gaps do not show a strong and consistent size dependency, in disagreement with the predictions of quantum confinement theory. The d. of excited bound states and absorption spectrum have been calcd. for four smallest BN clusters within the first ionization potential cut-off energy. The relative stability of different BN clusters has been further explored by studying principal point defects and their complexes including topol. B-N bond rotational defects, vacancies, antisites and interstitials. The latter have the lowest energy of formation.
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813Kaur, P.; Sekhon, S.; Kumar, V. Empty cage to three-dimensional structural transition in nanoparticles of III-V compound semiconductors: The finding of magic (AlP)13 and (GaP)32. Phys. Rev. B: Condens. Matter Mater. Phys. 2012, 85, 085429, DOI: 10.1103/PhysRevB.85.085429813https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XkslCgtLY%253D&md5=ff28e282b48d364796c1b4449dba80e4Empty cage to three-dimensional structural transition in nanoparticles of III-V compound semiconductors: the finding of magic (AlP)13 and (GaP)32Kaur, Prabhsharan; Sekhon, S. S.; Kumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2012), 85 (8), 085429/1-085429/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Small nanoparticles of III-V compd. semiconductors have often been considered to have open-cage structures. However, using first-principles calcns., we report the finding of a structural transition from empty-cage structures for (AlN)n and (GaN)n nanoparticles up to n = 34 that we studied, to a filled-cage structure for (InN)32. Further, phosphides and arsenides of Al and In have an early transition to three-dimensional (3D) filled-cage structures. Our results show that a 3D (AlP)13 is strongly magic with high binding energy and large highest occupied-LUMO gap. But nanoparticles of GaP show a transition from an empty cage for n = 13 to a strongly magic 3D filled cage for n = 32. The latter has a cage of (GaP)28 and a (GaP)4 squashed cube inside, the atoms on which are well connected with the cage. The bonding characteristics and the reason for structural transition are discussed.
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814Kaur, P.; Sekhon, S.; Kumar, V. Prediction of rock salt structure of (InN)32 nanoparticles from first principles calculations. J. Chem. Phys. 2013, 138, 114310, DOI: 10.1063/1.4795580814https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXktlKksrg%253D&md5=8f8e345210a3be2cd65b6eeaf00c0a3cPrediction of rock salt structure of (InN)32 nanoparticles from first principles calculationsKaur, Prabhsharan; Sekhon, S. S.; Kumar, VijayJournal of Chemical Physics (2013), 138 (11), 114310/1-114310/5CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)From first principles calcns., we show that (InN)32 nanoparticles favor rock salt structure compared with wurtzite structure in bulk. A phase transition from wurtzite to rock salt structure is known to occur in bulk InN at 12.1 GPa and higher values of pressure for AlN and GaN. However, at the nanoscale it is shown that this structural transition takes place in (InN)32 without applying pressure. The charge asymmetry value "g" and cation/anion size ratio in InN describe very well this behavior. Similar studies on nanoparticles of AlN and GaN as well as a few other binary compds. such as MgS, AgI, ZnO, and CdSe, however, do not show such a transition. The results suggest (InN)32 to be a unique candidate as further calcns. on a few larger size (InN)n nanoparticles show that a filled cage (two shells) (InN)12@(InN)48 structure of (InN)60 has higher binding energy compared with a rock salt structure of (InN)64 leading to the conclusion that other 3D structures are likely to become favorable over rock salt structure for larger sizes. (c) 2013 American Institute of Physics.
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815Kiran, B.; Kandalam, A. K.; Rallabandi, R.; Koirala, P.; Li, X.; Tang, X.; Wang, Y.; Fairbrother, H.; Gantefoer, G.; Bowen, K. (PbS)32: A baby crystal. J. Chem. Phys. 2012, 136, 024317, DOI: 10.1063/1.3672166815https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XmsVeksA%253D%253D&md5=059b75b3b3d0c5570c476e718d9991d3(PbS)32: A baby crystalKiran, B.; Kandalam, Anil K.; Rallabandi, Rameshu; Koirala, Pratik; Li, Xiang; Tang, Xin; Wang, Yi; Fairbrother, Howard; Gantefoer, Gerd; Bowen, KitJournal of Chemical Physics (2012), 136 (2), 024317/1-024317/7CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Theor. calcns. based on d. functional theory found (PbS)32 to be the smallest cubic cluster for which its inner (PbS)4 core enjoys bulk-like coordination. Cubic (PbS)32 is thus a baby crystal, i.e., the smallest cluster, exhibiting 6-fold coordination, that can be replicated to obtain the bulk crystal. The calcd. dimensions of the (PbS)32 cluster further provide a rubric for understanding the pattern of aggregation when (PbS)32 clusters are deposited on a suitable surface, i.e., the formation of square and rectangular, cryst. nano-blocks with predictable dimensions. Expts. in which mass-selected (PbS)32 clusters were soft-landed onto a highly ordered pyrolytic graphite surface and the resulting aggregates imaged by scanning tunneling microscopy provide evidence in direct support of the computational results. (c) 2012 American Institute of Physics.
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816Ueno, M.; Onodera, A.; Shimomura, O.; Takemura, K. X-ray observation of the structural phase transition of aluminum nitride under high pressure. Phys. Rev. B: Condens. Matter Mater. Phys. 1992, 45, 10123– 10126, DOI: 10.1103/PhysRevB.45.10123816https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38Xis1KisLY%253D&md5=673bc49760e9a5296bc7cbbb97b6d537X-ray observation of the structural phase transition of aluminum nitride under high pressureUeno, M.; Onodera, A.; Shimomura, O.; Takemura, K.Physical Review B: Condensed Matter and Materials Physics (1992), 45 (17), 10123-6CODEN: PRBMDO; ISSN:0163-1829.The III-V compd. AlN was studied under pressure to 30 GPa by x-ray diffraction in a diamond-anvil cell. At 22.9 GPa the wurtzite-to-rocksalt phase transition takes place accompanied by a vol. redn. of 17.9%. The axial ratio c/a in the wurtzite phase monotonically decreases with increasing pressure from the atm. value of 1.60.
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817Ueno, M.; Yoshida, M.; Onodera, A.; Shimomura, O.; Takemura, K. Stability of the wurtzite-type structure under high pressure: GaN and InN. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 49, 14– 21, DOI: 10.1103/PhysRevB.49.14817https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXhsV2nu74%253D&md5=9d168f4804a8e62cda695e9667b1a2ddStability of the wurtzite-type structure under high pressure: GaN and InNUeno, Masaki; Yoshida, Minoru; Onodera, Akifumi; Shimomura, Osamu; Takemura, KenichiPhysical Review B: Condensed Matter and Materials Physics (1994), 49 (1), 14-21CODEN: PRBMDO; ISSN:0163-1829.High-pressure in situ x-ray-diffraction studies on GaN and InN were carried out using an imaging-plate technique and a diamond-anvil cell up to about 60 GPa. The 2 compds. crystallize in the wurtzite-type structure at ambient conditions. The axial ratio c/a of GaN remains unchanged from the ambient value of 1.626 whereas c/a of InN is considerably decreased from 1.613 to 1.597 with increasing pressure to about 15 GPa. Equation-of-state data obtained for the wurtzite phase have yielded the bulk modulus of GaN to be 237(31) GPa and that of InN to be 125.5(4.6) GPa. Structural phase transition into the rocksalt-type structure takes place in GaN at 52.2 GPa and in InN at 12.1. The trend in the transition pressures of the III-V nitrides is discussed in terms of various ionicity scales.
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818Wang, J.; Ma, L.; Zhao, J.; Wang, G.; Chen, X.; Bruce King, R. Electronic and magnetic properties of manganese and iron-doped GanAsn nanocages (n = 7–12). J. Chem. Phys. 2008, 129, 044908, DOI: 10.1063/1.2960625818https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptlOisr8%253D&md5=3e5457ad223e2c23dcbed717a0319374Electronic and magnetic properties of manganese and iron-doped GanAsn nanocages (n=7-12)Wang, Jianguang; Ma, Li; Zhao, Jijun; Wang, Guanghou; Chen, Xiaoshuang; King, R. BruceJournal of Chemical Physics (2008), 129 (4), 044908/1-044908/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)The electronic and magnetic properties of Mn- or Fe-doped GanAsn (n = 7-12) nanocages were studied using gradient-cor. d.-functional theory considering doping at substitutional, endohedral, and exohedral sites. When doped with one atom, the most energetically favorable site gradually moves from surface (n = 7-11) to interior (n = 12) sites for the Mn atom, while the most preferred doping site of the Fe atom alternates between the surface (n = 7,9,11) and interior (n = 8,10,12) sites. All of the ground-state structures of Mn@anAsn have the atomlike magnetic moment of 5 μB, while the total magnetic moments of the most stable Fe@anAsn cages for each size are ∼2 μB except for the 4 μB magnetic moment of Fe@a12As12. Charge transfer and hybridization between the 4s and 3d states of Mn or Fe and the 4s and 4p states of As were found. The antiferromagnetic (AFM) state of Mn2@anAsn is more energetically favorable than the ferromagnetic (FM) state. However, for Fe2@anAsn the FM state is more stable than the AFM state. The local magnetic moments of Mn and Fe atoms in the GanAsn cages are ∼4 μB and 3 μB in the FM and AFM states, resp. For both Mn and Fe bidoping, the most energetically favorable doping sites of the transition metal atoms are located on the surface of the GanAsn cages. The computed magnetic moments of the doped Fe and Mn atoms agree excellently with the theor. and exptl. values in the Fe(Mn)/GaAs interface as well as (Ga, Mn)As dil. magnetic semiconductors. (c) 2008 American Institute of Physics.
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819Lu, P.; Wu, C.; Li, Y.; Yu, Z.; Cao, H.; Wang, S. Investigation on structural, electronic, and magnetic properties of Mn-doped Ga12N12 clusters. J. Mater. Sci. 2013, 48, 8552– 8558, DOI: 10.1007/s10853-013-7674-1819https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlalu7nE&md5=3e745da6a6b8f66260027a62814115ccInvestigation on structural, electronic, and magnetic properties of Mn-doped Ga12N12 clustersLu, Pengfei; Wu, Chengjie; Li, Yiluan; Yu, Zhongyuan; Cao, Huawei; Wang, ShuminJournal of Materials Science (2013), 48 (24), 8552-8558CODEN: JMTSAS; ISSN:0022-2461. (Springer)The structural, electronic, and magnetic properties of Ga12N12 cluster doped with monodoped and bidoped Mn atoms were investigated based on the d. functional theory. Substitutional, exohedral, and endohedral configurations are considered. The substitutional doping is found to be most favorable for monodoped clusters, while the bidoped clusters prefer the exohedral isomers. For all the isomer, the magnetic moment is mainly derived from 3d orbitals of Mn atom. The exohedral and endohedral bidoped Ga12N12 clusters all favor antiferromagnetic state.
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820Lu, P.; Wu, C.; Cong, Z.; Li, Y.; Zhang, X.; Yu, Z.; Cao, H. Fe-doped Ga12N12 clusters: Electronic and magnetic properties. Mod. Phys. Lett. B 2013, 27, 1350222, DOI: 10.1142/S0217984913502229820https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVWgtrnE&md5=d0995cf7a6cf8ddbd86c71f96bbc1311Fe-doped Ga12N12 clusters: electronic and magnetic propertiesLu, Pengfei; Wu, Chengjie; Cong, Zixiang; Li, Yiluan; Zhang, Xianlong; Yu, Zhongyuan; Cao, HuaweiModern Physics Letters B (2013), 27 (30), 1350222/1-1350222/10CODEN: MPLBET; ISSN:0217-9849. (World Scientific Publishing Co. Pte. Ltd.)In this paper, we have investigated the structural, electronic and magnetic properties of Ga12N12 cluster doped with monodoped and bidoped Fe atoms within the d. functional theory (DFT). Substitutional, exohedral and endohedral doping are considered. It is obsd. that both monodoped and bidoped clusters tend to be in exohedral doping. Mulliken population anal. is performed to obtain the charge transfer and magnetic moment. The magnetic moment is mainly derived from 3d orbitals of Fe atom for all isomers, while the magnetic properties would rely on the Fe-Fe distance.
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821Longo, R.; Carrete, J.; Aguilera-Granja, F.; Vega, A.; Gallego, L. A density-functional study of the structures and electronic properties of neutral, anionic, and endohedrally doped InxPx clusters. J. Chem. Phys. 2009, 131, 074504, DOI: 10.1063/1.3206844821https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVCksr3K&md5=78eed945b2ec7ad003a9d1472219f9ffA density-functional study of the structures and electronic properties of neutral, anionic, and endohedrally doped InxPx clustersLongo, R. C.; Carrete, J.; Aguilera-Granja, F.; Vega, A.; Gallego, L. J.Journal of Chemical Physics (2009), 131 (7), 074504/1-074504/11CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)We report extensive ab initio calcns. of the structures, binding energies, and magnetic moments of InxPx and InxPx‾ clusters (x = 1-15) using a d.-functional method that employs linear combinations of pseudoat. orbitals as basis sets, nonlocal norm-conserving pseudopotentials, and the generalized gradient approxn. for exchange and correlation. Our results, which are compared with those obtained previously for some of these clusters by means of all-electron calcns., show that hollow cages with alternating In-P bonds are energetically preferred over other structures for both the neutral and anionic species within the range x = 6-15. We also consider the endohedrally doped X@In10P10 (X = Cr,Mn,Fe,Co) and Ti@InxPx (x = 7-12) clusters. Our results show that, except for Ti@In7P7 and Ti@In8P8, the transition metal atoms preserve their at. spin magnetic moments when encapsulated in the InP cages, instead of suffering either a spin crossover or a spin quenching due to hybridization effects. We also show that the stabilities of some empty and doped InP cages can be explained on the basis of the jellium model. (c) 2009 American Institute of Physics.
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822Ding, J.-N.; Yuan, N.-Y.; Li, C.-L.; Wang, X.-Q.; Chen, G.-G.; Chen, X.-S.; Lu, W. Studies on structures, electronic and magnetic properties of TM-doped InnSbn (n = 7–12, 14, 16) clusters (TM = Mn, Fe, and Co). J. Appl. Phys. 2011, 109, 014322, DOI: 10.1063/1.3531533822https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmsFCksA%253D%253D&md5=b753ca248bbe338e47edb00deb4c5c06Studies on structures, electronic and magnetic properties of TM-doped InnSbn (n = 7-12,14,16) clusters (TM = Mn, Fe, and Co)Ding, Jian-Ning; Yuan, Ning-Yi; Li, Chang-Lin; Wang, Xiu-Qin; Chen, Guang-Gui; Chen, Xiao-Shuang; Lu, WeiJournal of Applied Physics (2011), 109 (1), 014322/1-014322/7CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)We study the geometric, electronic, and magnetic properties of the title clusters the DFT-PBE method. For single-atom doping, three doping modes (substitutional, endohedral, and exohedral) were considered. The doped clusters are magnetic except Co-doped In7Sb7 and Co-doped In14Sb14. The lowest energy configurations of TM2In16Sb16 clusters are ferromagnetic (FM) with the TM atoms at the nearest neighbor position; the coupling between the TM atoms is mainly governed by the FM interaction via TM-TM direct interaction. The hybridization between Mn 3d state and the Sb 5p state is also favorable to the stability of FM state. (c) 2011 American Institute of Physics.
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823Liu, C.; Tkachenko, N. V.; Popov, I. A.; Fedik, N.; Min, X.; Xu, C. Q.; Li, J.; McGrady, J. E.; Boldyrev, A. I.; Sun, Z. M. Structure and bonding in [Sb@In8Sb12]3– and [Sb@In8Sb12]5–. Angew. Chem., Int. Ed. 2019, 58, 8367– 8371, DOI: 10.1002/anie.201904109823https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXptlOgtrk%253D&md5=fb32af7ae6cc13922f06ba1d03df4f00Structure and Bonding in [Sb@In8Sb12]3- and [Sb@In8Sb12]5-Liu, Chao; Tkachenko, Nikolay V.; Popov, Ivan A.; Fedik, Nikita; Min, Xue; Xu, Cong-Qiao; Li, Jun; McGrady, John E.; Boldyrev, Alexander I.; Sun, Zhong-MingAngewandte Chemie, International Edition (2019), 58 (25), 8367-8371CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors report the characterization of [K([2.2.2]crypt)]4[In8Sb13], which proves to contain a 1:1 mixt. of [Sb@In8Sb12]3- and [Sb@In8Sb12]5-. The tri-anion displays perfect Th symmetry, the 1st completely inorg. mol. to do so, and contains eight equiv. In3+ centers in a cube. The gas-phase potential energy surface of the penta-anion has eight equiv. min. where the extra pair of electrons is localized on one In+ center, and these min. are linked by low-lying transition states where the electron pair is delocalized over two adjacent centers. The best fit to the electron d. was obtained from a model where the structure of the 5- cluster lies close to the gas-phase transition state.
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824Wang, B.; Nagase, S.; Zhao, J.; Wang, G. Structural growth sequences and electronic properties of zinc oxide clusters (ZnO)n (n = 2-18). J. Phys. Chem. C 2007, 111, 4956– 4963, DOI: 10.1021/jp066548v824https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXisF2iuro%253D&md5=c8028972bac7175e986fa9b594590286Structural Growth Sequences and Electronic Properties of Zinc Oxide Clusters (ZnO)n (n=2-18)Wang, Baolin; Nagase, Shigeru; Zhao, Jijun; Wang, GuanghouJournal of Physical Chemistry C (2007), 111 (13), 4956-4963CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The structural and electronic properties of (ZnO)n (n = 2-18) clusters were studied using gradient-cor. d.-functional theory (DFT). The starting structures were generated from empirical genetic algorithm simulations or intuitive constructions. The lowest-energy structures of (ZnO)n were then selected from a no. of structural isomers via DFT optimization. For small clusters (n = 2-7), ring structures were found to be the most stable. Three-dimensional cage and tube structures become energetically preferable for larger clusters (n = 9-18), and the competition between cage and tube structures leads to the alternative appearance of these two types of structures as global min. The size evolution of electronic properties for zinc oxide clusters from ring toward cage or tube is discussed.
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825Liu, H.; Wang, S.; Zhou, G.; Wu, J.; Duan, W. Structural, electronic, and magnetic properties of manganese-doped Zn12O12 clusters: A first-principles study. J. Chem. Phys. 2006, 124, 174705, DOI: 10.1063/1.2194015825https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XksFChsbs%253D&md5=90e5f089cb2ee2509d34f63f089b9535Structural, electronic, and magnetic properties of manganese-doped Zn12O12 clusters: A first-principles studyLiu, Haitao; Wang, Shanying; Zhou, Gang; Wu, Jian; Duan, WenhuiJournal of Chemical Physics (2006), 124 (17), 174705/1-174705/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)A first-principles study has been performed to evaluate the structural, electronic, and magnetic properties of Zn12O12 clusters doped with one or two Mn atoms. The substitutional, exohedral, and endohedral dopings are taken into account. For the monodoped clusters, the substitutional isomer is most energetically favorable, and an exohedral isomer may appear as a low-lying metastable state. All isomers present 5 μB magnetic moment that is mainly contributed by the Mn-3d component. For the bidoped clusters, the antiferromagnetic state is degenerate with the ferromagnetic state at larger Mn-Mn distance (>5 A), while it is more energetically favorable at smaller Mn-Mn distance. Thus, the cohesion of bidoped isomer is sensitive to the magnetic coupling or chem. bonding. The endohedral bidoped isomer is found to be a stable local min., and the direct Mn-Mn interaction causes the redn. of local magnetic moment of Mn to about 4 μB.
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826Liu, H.; Zhang, J.-M. Investigation on structure, electronic and magnetic properties of Cr doped (ZnO)12 clusters: First-principles calculations. Phys. E 2018, 99, 51– 57, DOI: 10.1016/j.physe.2018.01.014826https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitVegtb8%253D&md5=77ba58174faaf098690e5c00f4949af7Investigation on structure, electronic and magnetic properties of Cr doped (ZnO)12 clusters: First-principles calculationsLiu, Huan; Zhang, Jian-MinPhysica E: Low-Dimensional Systems & Nanostructures (Amsterdam, Netherlands) (2018), 99 (), 51-57CODEN: PELNFM; ISSN:1386-9477. (Elsevier B.V.)The structural, electronic, and magnetic properties of (ZnO)12 clusters doped with Cr atoms have been investigated by using spin-polarized first-principles calcns. The exohedral a3 isomer is favorable than endohedral a2 isomer. The isomer a1 and a5 resp. have the narrowest and biggest gap between highest unoccupied MO and the LUMO (HOMO-LUMO) of 0.473 and 1.291 eV among these five monodoped isomers. The magnetic moment may be related to the local environment around the Cr atom that the a2 isomer whose total magnetic moment is 6 μB while the other monodoped isomers which all isomers have nearly total magnetic moments 4 μB. For Cr-doped (ZnO)12 on a1 or a3 isomer, the DOS of spin-up channel cross the Fermi level EF showing a finite magnitude near the Fermi level which might be useful for half metallic character. For the bidoped cases, the exohedral isomers are found to be most favorable. Including all bipoed isomers of substitutional, exohedral and endohedral bidoped clusters, the total magnetic moment of the ferromagnetic (antiferromagnetic) state is 8 (0) μB and the HOMO-LUMO gap of antiferromagnetic state is slightly larger than that of ferromagnetic state. The magnetic coupling between the Cr atoms in bidoped configurations is mainly governed by the competition between direct Cr and Cr atoms antiferromagnetic interaction and the ferromagnetic interaction between two Cr atoms via O atom due to strong p-d hybridization. Most importantly, we show that the exohedral bidoped (ZnO)12 clusters favor the ferromagnetic state, which may have the future applications in spin-dependent magneto-optical and magneto-elec. devices.
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827Baei, M. T.; Peyghan, A. A.; Bagheri, Z. First principles study on encapsulation of alkali metals into ZnO nanocage. Chin. J. Chem. Phys. 2012, 25, 671– 675, DOI: 10.1088/1674-0068/25/06/671-675827https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjtVWiu7Y%253D&md5=2e69f1ab93270af13e6b86fb7b9198bdFirst principles study on encapsulation of alkali metals into ZnO nanocageBaei, Mohammad T.; Peyghan, Ali Ahmadi; Bagheri, ZarghamChinese Journal of Chemical Physics (2012), 25 (6), 671-675, 5 pp.CODEN: CJCPA6; ISSN:1674-0068. (Chinese Physical Society)Encapsulation of alkali metals (Li, Na, K and Rb) into Zn12O12 nanocage has been investigated using d. functional theory. Encapsulation of Li and Na atoms is found to be thermodynamically favorable at 298 K and 100 kPa, with neg. Gibbs free energy change ΔG of about -130.12 and -68.43 kJ/mol, resp. By increasing the size of encapsulated atom the process become less favorable so that in the cases of K and Rb encapsulations the ΔG values are pos. The results indicate that the LUMO, Fermi level and specially HOMO of the cluster are shifted to higher energies so that the HOMO-LUMO gap of the cluster is significantly narrowed in all the cases. After encapsulation of the alkali metals the work function of cluster is decreased due to the shift of the Fermi level to higher energies. Therefore, the emitted electron c.d. from the Zn12O12 cluster will be increased.
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828Nanavati, S. P.; Sundararajan, V.; Mahamuni, S.; Ghaisas, S.; Kumar, V. Discovery of a nonstoichiometric Zn11MnSe13 magnetic magic quantum dot from ab initio calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 84, 045306, DOI: 10.1103/PhysRevB.84.045306828https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpslGnsrs%253D&md5=3939be016521dbbc68f714d2b17e7322Discovery of a nonstoichiometric Zn11MnSe13 magnetic magic quantum dot from ab initio calculationsNanavati, Sachin P.; Sundararajan, Vijayaraghavan; Mahamuni, Shailaja; Ghaisas, S. V.; Kumar, VijayPhysical Review B: Condensed Matter and Materials Physics (2011), 84 (4), 045306/1-045306/6CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Ab initio calcns. on ZnSe quantum dots (QDs) doped with one Mn atom have predicted a new nonstoichiometric magnetic magic Zn11MnSe13 structure in contrast to QDs of undoped ZnSe that are stoichiometric and exhibit magic behavior for ZnnSen with n = 13 and 34. Such doping would lead to a high abundance of only one specie (the magic QD) that would be produced preferentially. The stoichiometric Znn-1MnSen QDs have a large magnetic moment of 5 μB that is predominantly localized on the Mn site. The nonstoichiometric QD has a reduced magnetic moment of 3 μB due to strong covalent bonding of the Mn atom with the excess Se atom and a small gap between the HOMO and the LUMO. Charging this magic QD with two electrons leads to a large HOMO-LUMO gap of 1.8 eV and 5 μB magnetic moment.
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829Shakerzdeh, E.; Tahmasebi, E.; Shamlouei, H. R. The influence of alkali metals (Li, Na and K) interaction with Be12O12 and Mg12O12 nanoclusters on their structural, electronic and nonlinear optical properties: A theoretical study. Synth. Met. 2015, 204, 17– 24, DOI: 10.1016/j.synthmet.2015.03.008829https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVCnu7g%253D&md5=f04b71f70e38fb36adf3fef2ec997424The influence of alkali metals (Li, Na and K) interaction with Be12O12 and Mg12O12 nanoclusters on their structural, electronic and nonlinear optical properties: A theoretical studyShakerzdeh, Ehsan; Tahmasebi, Elham; Shamlouei, Hamid RezaSynthetic Metals (2015), 204 (), 17-24CODEN: SYMEDZ; ISSN:0379-6779. (Elsevier B.V.)D. functional theory (DFT) calcns. have been carried out to study the influence of alkali metals (Li, Na and K) interaction with Be12O12 and Mg12O12 nanoclusters on their structural, electronic and nonlinear optical properties. The interaction of Li, Na and K atoms is found to be remarkably narrowed the HOMO-LUMO gaps of the considered clusters. The electronic properties of these clusters are strongly sensitive to interaction with the alkali metals. Moreover, the encapsulation of alkali metals inside of the considered clusters slightly enhances their hyperpolarizabilities with one exception. The encapsulation of Li atom inside of the Mg12O12 nanocluster is energetically favorable and leads to a large hyperpolarizability. Furthermore, the adsorption of the alkali metals on the surface of the considered nanoclusters is investigated. The alkali metals adsorption on the surfaces of the clusters is energetically favorable and causes extremely large nonlinear optical (NLO) response in comparison to encapsulated forms. Therefore, the interaction of alkali metals with Be12O12 and Mg12O12 nanoclusters plays an important role in tuning their electronic and nonlinear optical properties. This work theor. devises novel multifunctional inorg. metal oxide-based nanostructures via interaction with alkali atoms, which could be promoted their potential applications in electronic devices and high-performance NLO materials.
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830Groh, M. F.; Müller, U.; Isaeva, A.; Ruck, M. Ionothermal syntheses, crystal structures, and chemical bonding of the rhodium-centered clusters [RhBi9]4+ and [(RhBi7)I8]. Z. Anorg. Allg. Chem. 2017, 643, 1482– 1490, DOI: 10.1002/zaac.201700242830https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsV2rt7jE&md5=e3e85a6ef98e5b6c747d26e4b7b208e6Ionothermal Syntheses, Crystal Structures, and Chemical Bonding of the Rhodium-Centered Clusters [RhBi9]4+ and [(RhBi7)I8]Groh, Matthias F.; Mueller, Ulrike; Isaeva, Anna; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2017), 643 (21), 1482-1490CODEN: ZAACAB; ISSN:1521-3749. (Wiley-VCH Verlag GmbH & Co. KGaA)The first filled Bi95+ polycation was isolated in the form of [RhBi9](AlCl4)4 crystals by dissoln. of the solid precursor Bi12-xRhX13-x in the Lewis-acidic ionic liq. [BMIm]Cl·3.6AlCl3 (BMIm = 1-butyl-3-methylimidazolium) at 140 °C. In the monoclinic crystal structure [P21/n, a = 1217.5(2) pm, b = 1741.6(3) pm, c = 5085.7(7) pm, β = 90.117(8)°], the almost spherical [RhBi9]4+ polycations (approx. D3h symmetry; Rh-Bi 276 ± 3 pm) show pronounced orientational disorder. Shiny black needles of Bi7RhI8 were obtained from the reaction of rhodium, bismuth, and BiI3 in the ionic liq. [BMIm]Cl·1.3AlCl3 at 200 °C. Bi7RhI8 [P21/n, a = 943.10(1) pm, b = 1582.40(1) pm, c = 1645.40(1) pm, β = 95.48(1)°] is isostructural to Bi7RhBr8 and consists of mol. clusters [(RhBi7)I8]. The rhodium atom centers a pentagonal bipyramid of bismuth atoms, and the two apical bismuth atoms are in square-planar coordination of iodide ions. DFT-based calcns. indicate strong bismuth-rhodium bonding with predominantly covalent character for both clusters. The electronic structure of the Bi95+ cage is notably modified by this interaction, but the characteristic bonding features of the host cluster with the D3h configuration are still maintained. In Bi7RhI8, on the other hand, bonding is dictated by the spatial distribution of mutually repelling iodine atoms, and the Bi-Rh bonding is highly polar.
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831Ruck, M.; Dubenskyy, V.; Söhnel, T. Structure and bonding of Pd@[Bi10]4+ in the subbromide Bi14PdBr16. Angew. Chem., Int. Ed. 2003, 42, 2978– 2982, DOI: 10.1002/anie.200250801831https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXlslGks7g%253D&md5=453c763d1dacb6f29b927013f96bbd29Structure and bonding of Pd@[Bi10]4+ in the subbromide Bi14PdBr16Ruck, Michael; Dubenskyy, Vitaly; Soehnel, TiloAngewandte Chemie, International Edition (2003), 42 (26), 2978-2982CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The bismuth palladium subbromide Bi14PdBr16 was prepd. and characterized by x-ray crystallog. Bi14PdBr16 is comprised of the cationic cluster [PdBi10]4+, a pentagonal antiprism of ten Bi atoms with a Pd atom in the center, and polymeric 1∞[BiBr4-] anions. Quantum mech. calcns. were performed on the bonding of Bi14PdBr16 and the isolated cluster cation [PdBi10]4+.
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832Dubenskyy, V.; Ruck, M. Das subchlorid Bi16PdCl22: Pd@Bi104+-polykationen in einem raumnetzwerk aus chlorobismutat(III)-anionen. Z. Anorg. Allg. Chem. 2004, 630, 2458– 2462, DOI: 10.1002/zaac.200400206832https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXpslelu7c%253D&md5=7d1b527284f40205fc6dacafc7ff34e0The subchloride Bi16PdCl22. Pd@Bi104+ polycations inside a framework of chloro-bismuthate(III) anionsDubenskyy, Vitaly; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2004), 630 (13-14), 2458-2462CODEN: ZAACAB; ISSN:0044-2313. (Wiley-VCH Verlag GmbH & Co. KGaA)Black, air-sensitive crystals of Bi16PdCl22 were synthesized from the elements by cooling melts slowly from 1270 K to room temp. X-ray diffraction on single-crystals revealed that the compd. crystallizes with the triclinic space group P‾1 and lattice parameters a = 2047.7(4) pm, b = 2132.1(4) pm, c = 2145.4(4) pm, α = 91.09(3)°, β = 95.14(3)°, γ = 93.16(3)°, dc = 6.034, 25,371 obsd. reflections with Fo > 4σ(Fo), 1417 refined parameters, R1 = 0.029, wR2 = 0.086 (all data) . In the crystal structure polycations Pd@Bi104+ with the shape of pentagonal Archimedean antiprisms (D5d symmetry) are embedded in the cavities of a pseudo-cubic framework 3∞[Bi6Cl22]4- formed by chloro-bismuthate(III) anions that share vertices and edges. The 2×2×2 superstructure results from 3 different main orientations of the polycations occurring with ratio 3:3:2. The weak interaction between the interstitial closed-shell Pd0 and the electron-precise arachno-cluster Bi104+ is represented by the formulation as a cationic inclusion compd. Pd@Bi104+.
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833Groh, M. F.; Wolff, A.; Wahl, B.; Rasche, B.; Gebauer, P.; Ruck, M. Pentagonal bismuth antiprisms with endohedral palladium or platinum atoms by low-Temperature syntheses. Z. Anorg. Allg. Chem. 2017, 643, 69– 80, DOI: 10.1002/zaac.201600354833https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVSiurnE&md5=3e7c1bc712cfb51ba9a2240a3fd7d37dPentagonal Bismuth Antiprisms with Endohedral Palladium or Platinum Atoms by Low-Temperature SynthesesGroh, Matthias F.; Wolff, Alexander; Wahl, Bernhard; Rasche, Bertold; Gebauer, Paul; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2017), 643 (1), 69-80CODEN: ZAACAB; ISSN:1521-3749. (Wiley-VCH Verlag GmbH & Co. KGaA)Authors present the syntheses, crystal structures, and properties of five metal-rich salts contg. the Bi104+ pentagonal antiprism with an endohedral palladium or, for the first time, platinum atom. Tetragonal [Pt@Bi10](AlBr4)4 [P42/n at 296(1) K; P4 at 150(2) K] was obtained by reacting platinum, bismuth, and bismuth tribromide in [BMIm]Br·4.1AlBr3 at 140° (BMIm = 1-butyl-3-methylimidazolium). Monoclinic [Pt@Bi10](AlBr4)2(Al2Br7)2 [P21/n] occurs as byproduct. The two corresponding palladium compds. result from the dissoln. of Bi16PdCl22 in [BMIm]Br·4.1AlBr3. [Pd@Bi10](AlBr4)4 [P42/n] adopts a disordered structure homeotypic to its platinum analog. [Pd@Bi10](AlBr4)2(Al2Br7)2 [P21/n] is isostructural to [Pt@Bi10](AlBr4)2(Al2Br7)2. In all structures, the [M@Bi10]4+ cations are well sepd. by the bromido-aluminate anions with inter-cluster Bi···Bi distances longer than 520 pm. This is not the case in [Pd@Bi10][Bi2Sn6Cl22], which crystd. from a tin-contg. melt of the metals and BiCl3. In its monoclinic structure [P21/c], the cluster cations are arranged in chains along [001] with an inter-cluster distance of only 357 pm. Despite further structural evidence, DFT-based quantum chem. anal. gave no hint on inter-cluster bonding. According to the calcd. band structure as well as resistivity and magnetic susceptibility measurements, the black compd. is a diamagnetic semiconductor.
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834Wahl, B.; Erbe, M.; Gerisch, A.; Kloo, L.; Ruck, M. Nobel-metal centered polycations [Au@Bi10]5+ or [Pd@Bi10]4+ embedded in halogenido-bismuthate(III)-stannate(II) frameworks. Z. Anorg. Allg. Chem. 2009, 635, 743– 752, DOI: 10.1002/zaac.200900087834https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlslGku78%253D&md5=70b170042a1a9f723bcb203f3fa5f664Nobel-metal centered polycations [Au@Bi10]5+ or [Pd@Bi10]4+ embedded in halogenido-bismuthate(III)-stannate(II) frameworksWahl, Bernhard; Erbe, Manuela; Gerisch, Alexander; Kloo, Lars; Ruck, MichaelZeitschrift fuer Anorganische und Allgemeine Chemie (2009), 635 (4-5), 743-752CODEN: ZAACAB; ISSN:0044-2313. (Wiley-VCH Verlag GmbH & Co. KGaA)The metal-rich halides AuBi14-δSn2+δX21-δ (δ ≈ 0.4) and PdBi15-δSn1+δX21-δ(δ ≈ 0.6) with X = Cl, Br were crystd. from melts of the metals and BiX3. In the rhombohedral structures (space group R‾3; a ≈ 1050 pm; α ≈ 94°), noble-metal centered pentagonal antiprisms [Au@Bi10]5+ resp. [Pd@Bi10]4+ are embedded in halometalate frameworks 3∞[Bi4-δSn2+δX21-δ]5- resp. 3∞[Bi5-δSn1+δX21-δ]4-. Mixed BiIII/SnII site occupation allows the framework to adopt different charges. Further exchange of BiIIIX3 against SnIIX2 results in vacancies (6) on the position of an isolated halide ion. In quantum chem. calcns. the naked metal-clusters are stable in D5d symmetry with interat. distances close to the obsd. ones. The significance of interactions between the Wade-type host cluster Bi104++ and the closed-subshell guest atoms Au+ or Pd0 is reflected in the MO diagram, the population analyses and the ELI-D.
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835Lichtenberger, N.; Wilson, R. J.; Eulenstein, A. R.; Massa, W.; Clérac, R.; Weigend, F.; Dehnen, S. Main group metal–actinide magnetic coupling and structural response upon U4+ inclusion into Bi, Tl/Bi, or Pb/Bi cages. J. Am. Chem. Soc. 2016, 138, 9033– 9036, DOI: 10.1021/jacs.6b04363835https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFeku7zN&md5=d61c1009779c82c455c6a0060f19695cMain Group Metal-Actinide Magnetic Coupling and Structural Response Upon U4+ Inclusion Into Bi, Tl/Bi, or Pb/Bi CagesLichtenberger, Niels; Wilson, Robert J.; Eulenstein, Armin R.; Massa, Werner; Clerac, Rodolphe; Weigend, Florian; Dehnen, StefanieJournal of the American Chemical Society (2016), 138 (29), 9033-9036CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The encapsulation of actinide ions in intermetalloid clusters has long been proposed but was never realized synthetically. The authors report the isolation and exptl., as well as quantum chem., characterization of the U-centered clusters [U@Bi12]3-, [U@Tl2Bi11]3-, [U@Pb7Bi7]3-, and [U@Pb4Bi9]3-, upon reaction of (EE'Bi2)2- (E = Ga, Tl, E' = Bi; E = E' = Pb) and [U(C5Me4H)3] or [U(C5Me4H)3Cl] in 1,2-diaminoethane. For [U@Bi12]3-, magnetic susceptibility measurements rationalize an unprecedented antiferromagnetic coupling between a magnetic U4+ site and a unique radical Bi127- shell.
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836Lips, F.; Clérac, R.; Dehnen, S. [Eu@Sn6Bi8]4–: A mini-fullerane-type zintl anion containing a lanthanide ion. Angew. Chem., Int. Ed. 2011, 50, 960– 964, DOI: 10.1002/anie.201005655836https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmslOrsw%253D%253D&md5=834d12c6b97dd35b0be5fa256ba56ce5[Eu@n6Bi8]4-: A Mini-Fullerane-Type Zintl Anion Containing a Lanthanide IonLips, Felicitas; Clerac, Rodolphe; Dehnen, StefanieAngewandte Chemie, International Edition (2011), 50 (4), 960-964, S960/1-S960/41CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The reaction of [K([2.2.2]crypt)]2[Sn2Bi2]·en with [(C5Me4H)3Eu] yields [K([2.2.2]crypt)]4[Eu@Sn6Bi8]·1.1en (1) as extremely air sensitive brown crystals which were characterized by ESI-MS and EDX anal. The crystal structure of 1 shows that the [Eu@Sn6Bi8]4- anion consists of a fullerene-like Sn6Bi8 cage having 6 pentagonal and 3 square faces with an endohedral Eu ion. The magnetic properties of 1 were studied along with comprehensive quantum chem. investigations using DFT. The data support the existence of divalent Eu(II), and thus the Zintl anion exists as a [Sn6Bi8]6- shell. The DFT calcd. relative stabilities of various topol. isomers of the Sn6Bi8 cage were detd. DFT investigations were also performed on the hypothetical C14 fullerene and the C14H14 fullerane for comparison.
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837Lips, F.; Hołynska, M.łg.; Clerac, R.; Linne, U.; Schellenberg, I.; Pottgen, R.; Weigend, F.; Dehnen, S. Doped semimetal clusters: Ternary, intermetalloid anions [Ln@Sn7Bi7]4– and [Ln@Sn4Bi9]4– (Ln = La, Ce) with adjustable magnetic properties. J. Am. Chem. Soc. 2012, 134, 1181– 1191, DOI: 10.1021/ja209226b837https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFejtb3J&md5=7504c7e15622bac16ee02d2c9cd0a126Doped Semimetal Clusters: Ternary, Intermetalloid Anions [Ln@Sn7Bi7]4- and [Ln@Sn4Bi9]4- (Ln = La, Ce) with Adjustable Magnetic PropertiesLips, Felicitas; Holynska, Malgorzata; Clerac, Rodolphe; Linne, Uwe; Schellenberg, Inga; Poettgen, Rainer; Weigend, Florian; Dehnen, StefanieJournal of the American Chemical Society (2012), 134 (2), 1181-1191CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Two K([2.2.2]crypt) salts of lanthanide-doped semimetal clusters were prepd., both of which contain at the same time two types of ternary intermetalloid anions, [Ln@Sn7Bi7]4- and [Ln@Sn4Bi9]4-, in 0.70:0.30 (Ln = La) or 0.39:0.61 (Ln = Ce) ratios. The cluster shells represent nondeltahedral, fullerane-type arrangements of 14 or 13 main group metal atoms that embed the Ln3+ cations. The assignment of formal +III oxidn. states for the Ln sites was confirmed by magnetic measurements that reveal a diamagnetic La(III) compd. and a paramagnetic Ce(III) analog. Whereas the cluster anions with a 14-at. main-group metal cage represent the second examples in addn. to a related Eu(II) cluster published just recently, the 13-at. cages exhibit a yet unprecedented enneahedral topol. In contrast to the larger cages, which accord to the Zintl-Klemm-Busmann electron no.-structure correlation, the smaller clusters require a more profound interpretation of the bonding situation. Quantum chem. investigations served to shed light on these unusual complexes and showed significant narrowing of the HOMO-LUMO gap upon incorporation of Ce3+ within the semimetal cages.
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838Ababei, R.; Massa, W.; Weinert, B.; Pollak, P.; Xie, X.; Clérac, R.; Weigend, F.; Dehnen, S. Ionic-radius-driven selection of the main-group-metal cage for intermetalloid clusters [Ln@PbxBi14–x]q– and [Ln@PbyBi13–y]q– (x/q = 7/4, 6/3; y/q = 4/4, 3/3). Chem. - Eur. J. 2015, 21, 386– 394, DOI: 10.1002/chem.201404904838https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFGgtLrJ&md5=ccf1b1371517ac3d100b2ad7f8608292Ionic-Radius-Driven Selection of the Main-Group-Metal Cage for Intermetalloid Clusters [Ln@PbxBi14-x]q- and [Ln@PbyBi13-y]q- (x/q = 7/4, 6/3; y/q = 4/4, 3/3)Ababei, Rodica; Massa, Werner; Weinert, Bastian; Pollak, Patrik; Xie, Xiulan; Clerac, Rodolphe; Weigend, Florian; Dehnen, StefanieChemistry - A European Journal (2015), 21 (1), 386-394CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Reactions of the binary, pseudo-homoat. Zintl anion (Pb2Bi2)2- with Ln(C5Me4H)3 (Ln = La, Ce, Nd, Gd, Sm, Tb) in the presence of [2.2.2]crypt in ethane-1,2-diamine/toluene yielded ten [K([2.2.2]crypt)]+ salts of lanthanide-doped semimetal clusters with 13 or 14 surface atoms. Single-crystal x-ray diffraction and energy-dispersive X-ray spectroscopy indicated the presence of [Ln@Pb6Bi8]3-, [Ln@Pb3Bi10]3-, [Ln@Pb7Bi7]4-, or [Ln@Pb4Bi9]4- in single or double salts; the latter showed various ratios of the components in the solid state. The anions are the first ternary intermetalloid clusters comprising only elements of the sixth period of the periodic table, namely, Pb, Bi and lanthanides. This study, which was complemented by ESI mass spectrometry and 139La NMR spectroscopy in soln., rationalizes a continuous development of the ratio of 13:14-atom cages with the ionic radius of the embedded Ln3+ ion, which seems to select the most suitable cage type. Quantum chem. studies helped to analyze this situation in more detail and to explain the obsd. subtle influence of the at. radii. Magnetic measurements confirmed that the embedded Ln3+ ions keep their expected paramagnetic or diamagnetic nature.
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839Mitzinger, S.; Broeckaert, L.; Massa, W.; Weigend, F.; Dehnen, S. [V@Ge8As4]3– and [Nb@Ge8As6]3–: Encapsulation of electron-poor transition metal atoms. Chem. Commun. 2015, 51, 3866– 3869, DOI: 10.1039/C4CC10086G839https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFeqtL0%253D&md5=635c475373b92543861317bde0f7f569[V@Ge8As4]3- and [Nb@Ge8As6]3-: encapsulation of electron-poor transition metal atomsMitzinger, Stefan; Broeckaert, Lies; Massa, Werner; Weigend, Florian; Dehnen, StefanieChemical Communications (Cambridge, United Kingdom) (2015), 51 (18), 3866-3869CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)[K([2.2.2]crypt)]+ salts of [V@Ge8As4]3- and [Nb@Ge8As6]3- were obtained by extn. of quaternary phases with en/[2.2.2]crypt. The V-Ge-As anion is the first Zintl anion incorporating a (formal) V5+ cation, thus the smallest cation ever embedded within a main group (semi-)metal cage. It represents the second example of a novel 12-vertex cluster architecture. The bonding situation was elucidated by quantum chem., also allowing for a precise assignment of Ge vs. As atoms, being indistinguishable by x-ray diffraction.
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840Mitzinger, S.; Broeckaert, L.; Massa, W.; Weigend, F.; Dehnen, S. Understanding of multimetallic cluster growth. Nat. Commun. 2016, 7, 10480, DOI: 10.1038/ncomms10480840https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhtl2gsr8%253D&md5=7487b0e392426e4da104dc508532bc4cUnderstanding of multimetallic cluster growthMitzinger, Stefan; Broeckaert, Lies; Massa, Werner; Weigend, Florian; Dehnen, StefanieNature Communications (2016), 7 (), 10480CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)The elucidation of formation mechanisms is mandatory for understanding and planning of synthetic routes. For (bio-)org. and organometallic compds., this has long been realized even for very complicated mols., whereas the formation of ligand-free inorg. mols. has widely remained a black box to date. This is due to poor structural relationships between reactants and products and the lack of structurally related intermediates-due to the comparably high coordination flexibility of involved atoms. Here we report on investigations of the stepwise formation of multimetallic clusters, based on a series of crystal structures and complementary quantum-chem. studies of (Ge2As2)2-, (Ge7As2)2-, [Ta@Ge6As4]3-, [Ta@Ge8As4]3- and [Ta@Ge8As6]3-. The study makes use of efficient quantum-chem. tools, enabling the first detailed screening of the energy hypersurface along the formation of ligand-free inorg. species for a semi-quant. picture. The results can be generalized for an entire family of multimetallic clusters.
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841Lips, F.; Dehnen, S. Neither electron-precise nor in accordance with Wade–Mingos rules: The ternary cluster anion [Ni2Sn7Bi5]3–. Angew. Chem., Int. Ed. 2011, 50, 955– 959, DOI: 10.1002/anie.201005496841https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmslOqtA%253D%253D&md5=5c5a19175372b586c8e6210874644bddNeither Electron-Precise nor in Accordance with Wade-Mingos Rules: The Ternary Cluster Anion [Ni2Sn7Bi5]3-Lips, Felicitas; Dehnen, StefanieAngewandte Chemie, International Edition (2011), 50 (4), 955-959, S955/1-S955/34CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The ternary Zintl intermetalloid cluster anion, [K([2.2.2]crypt)]3[Ni2Sn7Bi5] (I), was prepd. from [K([2.2.2]crypt)]2[Sn2Bi2]·en (en = 1,2-ethylenediamine) and Ni(cod)2 (cod = 1,5-cyclooctadiene) in 15% yield. I was characterized by x-ray crystallog., ESI mass spectrometry and DFT investigation. Relative energies of all isomers of a given compn. [Ni2Sn12-xBix]3- for x = 0-12 were calcd. to find the most stable isomer of compd. I.
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842Wilson, R. J.; Hastreiter, F.; Reiter, K.; Büschelberger, P.; Wolf, R.; Gschwind, R. M.; Weigend, F.; Dehnen, S. [Co@Sn6Sb6]3–: An off-center endohedral 12-vertex cluster. Angew. Chem., Int. Ed. 2018, 57, 15359– 15363, DOI: 10.1002/anie.201807180842https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitVWqsrfL&md5=2355e6b610ead3f31259ebcd2c580836[Co@Sn6Sb6]3-: An Off-Center Endohedral 12-Vertex ClusterWilson, Robert J.; Hastreiter, Florian; Reiter, Kevin; Bueschelberger, Philipp; Wolf, Robert; Gschwind, Ruth M.; Weigend, Florian; Dehnen, StefanieAngewandte Chemie, International Edition (2018), 57 (47), 15359-15363CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Authors report on the asym. occupation of a 12-vertex cluster centered by a single metal atom. Three salts of related intermetalloid cluster anions, [Co@Sn6Sb6]3- (1), [Co2@Sn5Sb7]3- (2), and [Ni2@Sn7Sb5]3- (3) were synthesized, which have pseudo-C4v-sym. or pseudo-D4h-sym. 12-vertex Sn/Sb shells and interstitial Co- ions or Ni atoms. Anion 1 is a very unusual single-metal-"centered" 12-atom cluster, with the inner atom being clearly offset from the cluster center for energetic reasons. Quantum chem. served to assign atom types to the at. positions and relative stabilities of this cluster type. The studies indicate that the structures are strictly controlled by the total valence electron count-which is particularly variable in ternary intermetalloid cluster anions. Preliminary 119Sn NMR studies in soln., supported by quantum-chem. calcns. of the shifts, illustrate the complexity regarding Sn:Sb distributions of such ternary systems.
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843Lips, F.; Clerac, R.; Dehnen, S. [Pd3Sn8Bi6]4–: A 14-vertex Sn/Bi cluster embedding a Pd3 triangle. J. Am. Chem. Soc. 2011, 133, 14168– 14171, DOI: 10.1021/ja203302t843https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVOnsrzO&md5=50076ab03810978a98c85d42587c377f[Pd3Sn8Bi6]4-: A 14-Vertex Sn/Bi Cluster Embedding a Pd3 TriangleLips, Felicitas; Clerac, Rodolphe; Dehnen, StefanieJournal of the American Chemical Society (2011), 133 (36), 14168-14171CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The endohedral cluster anion [Pd3Sn8Bi6]4- crystallizes as its K([2.2.2]crypt)+ salt 1 upon reaction of [K([2.2.2]crypt)]2[Sn2Bi2]·en and Pd(dppe)2 in 1,2-diaminoethane (en)/toluene and incorporates a complete Pd3 triangular cluster within a medium-size 14-vertex cage of Sn and Bi atoms. 1 Was characterized by a combination of single crystal diffraction, ESI mass spectrometry, elemental anal., and magnetic measurements. According to quantum chem. studies, the Pd3 triangle interacts only weakly with the Sn/Bi cluster shell despite the relatively small cavity inside the cage.
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844Pham, H. T.; Nguyen, M. T. Theoretical investigation of metallic heterofullerenes of silicon and germanium mixed with phosphorus and arsenic atoms M-A8E6, A = Si, Ge; E = P, As; and M = Cr, Mo, W. J. Phys. Chem. A 2017, 121, 5056– 5066, DOI: 10.1021/acs.jpca.7b04631844https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpvVSqtrY%253D&md5=b3fd46b12b603a74362681c53471b6c3Theoretical Investigation of Metallic Heterofullerenes of Silicon and Germanium Mixed with Phosphorus and Arsenic Atoms M-A8E6, A = Si, Ge; E = P, As; and M = Cr, Mo, WPham, Hung Tan; Nguyen, Minh ThoJournal of Physical Chemistry A (2017), 121 (26), 5056-5066CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)Recently, metallic heterofullerenes were exptl. prepd. from mixed Ge-As clusters and heavier elements of groups 14 and 15. We found that the shape of these heterofullerenes doped by transition metals appears to be a general structural motif for both silicon and germanium clusters when mixing with phosphorus and arsenic atoms. Structural identifications for MSi8P6, MSi8As6, MGe8P6,and MGe8As6 clusters, with M being a transition metal of group 6(Cr, Mo and W), showed that most MA8E6 clusters, except for Cr-doped derivs. CrSi8As6, CrGe8P6, and CrGe8As6, exhibit a high symmetry fullerene shape in which metal dopant is centered in a D3h A8E6 heterocage consisting of six A3E2 pentagonal faces and three A2E2 rhombus faces. The stability of the MA8E6 metallic heterofullerene is significantly enhanced by formation an electron configuration of [1S2 1P6 1D10 1F14 1G18 2S2 2P6 2D10]. The A8E6 heterocages give a great charge transfer (∼4 electrons) to centered dopant, establishing subsequently a d10 configuration for metal, and as a consequence, it induces an addnl. stabilization of the resulting ME8P6 fullerene in a high symmetry D3h shape and completely quenches the high spin of the metal atom, finally yielding a singlet spin ground state.
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845Tam, N. M.; Pham, H. T.; Cuong, N. T.; Tung, N. T. A DFT investigation on geometry and chemical bonding of isoelectronic Si8N6V–, Si8N6Cr, and Si8N6Mn+ clusters. Chem. Phys. Lett. 2017, 685, 410– 415, DOI: 10.1016/j.cplett.2017.08.009There is no corresponding record for this reference.
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846Song, B.; Zhou, J.; Yong, Y.; He, P. Density functional investigation of transition-metal-encapsulated SinCn (n = 7–10) cagelike clusters. J. Phys. Chem. C 2010, 114, 10703– 10710, DOI: 10.1021/jp100745f846https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvF2qsbs%253D&md5=4c34a6aeb51477b3899ece2242c3c56bDensity Functional Investigation of Transition-Metal-Encapsulated SinCn (n = 7-10) Cagelike ClustersSong, Bin; Zhou, Jun; Yong, Yongliang; He, PimoJournal of Physical Chemistry C (2010), 114 (24), 10703-10710CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The geometries, stabilities, and electronic and magnetic properties of 3d and 4d transition-metal (TM)-encapsulated SinCn (n = 7-10) cagelike clusters were systematically investigated using the d. functional theory with generalized gradient approxn. SinCn cagelike structures doped with TM atoms are stable, esp. when they encapsulate 3d (or 4d) TM atoms. The formation of an endohedral structure strongly depends on the TM atom present and the SinCn cage size. Among the SinCn cages studied, the Si8C8 cage is the energetically optimal cage for encapsulating most of the 3d and 4d TM atoms. For TM@Si8C8, 3d and 4d TM dopants exhibit similar electronic and magnetic behaviors. The electronic properties of the TM@Si8C8 clusters are characterized by electron transfer from silicon and carbon atoms to TM atoms. The total magnetic moments of TM@Si8C8 clusters oscillate from 0 to 1 μB across the periodic table. The total magnetic moments are mainly located on the 3s and 3p states of Si atoms, and the 2p states of C atoms and TM atoms contribute the least.
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847Pham, H. T.; Nguyen, H. T.; Nguyen, M. T. Mn@B3N3Si8+: A stable singlet manganese-doped hetero-atom-mixed silicon fullerene. Struct. Chem. 2017, 28, 1887– 1893, DOI: 10.1007/s11224-017-0973-4847https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXptVahsr0%253D&md5=9d320dce83d3bb87bd7d15a0ce435642Mn@B3N3Si8+: a stable singlet manganese-doped hetero-atom-mixed silicon fullerenePham, Hung Tan; Nguyen, Huyen Thi; Nguyen, Minh ThoStructural Chemistry (2017), 28 (6), 1887-1893CODEN: STCHES; ISSN:1040-0400. (Springer)A B3N3Si8 cage is formed upon substitution of Si sites of rhombus faces of the pure Si14 cluster by B and N atoms. Doping by the ion Mn+ leads to the hetero-silicon fullerene B3N3Si8Mn+ which comprises three rhombi (BNBN, Si3B and Si3N) and four pentagons (two Si2B2N and two Si2BN2). Hetero-atoms form polarized Si-N and Si-B bonds as indicated by electron localization function (ELF) maps and NBO charges. The Mn center connects the B3N3Si8 cage by ionic interactions. Valence electrons of B3N3Si8Mn+ occupy a shell configuration of [1S2 1P6 1D10 1F14 1G12 2S2 2P6 2D10] and induce a certain thermodn. stability. The high spin of the Mn+ metal cation is completely quenched within the hetero-Si fullerene.
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848King, R. B.; Zhao, J. The isolable matryoshka nesting doll icosahedral cluster [As@Ni12@As20]3- as a ″superatom″: Analogy with the jellium cluster Al13- generated in the gas phase by laser vaporization. Chem. Commun. 2006, 4204– 4205, DOI: 10.1039/B607895H848https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtVCru7jJ&md5=d6c4558e9ed27624ee364ad6f895888cThe isolable matryoshka nesting doll icosahedral cluster [As@Ni12@As20]3- as a "superatom": analogy with the jellium cluster Al13- generated in the gas phase by laser vaporizationKing, R. Bruce; Zhao, JijunChemical Communications (Cambridge, United Kingdom) (2006), (40), 4204-4205CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The valence electrons in the recently reported icosahedral cluster [As@Ni12@As20]3- with a Russian matryoshka nesting doll structure can be partitioned so that the central As atom has the rare gas configuration, as As3-, and the intermediate Ni12 icosahedron receives 40 electrons from the lone pairs of the outer As20 dodecahedron to be isoelectronic with the Al13- jellium cluster found in mol. beam expts.
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849Sheong, F. K.; Chen, W. J.; Kim, H.; Lin, Z. Peeling the onion: A revised model of the electron count for matryoshka clusters. Dalton Trans. 2015, 44, 7251– 7257, DOI: 10.1039/C5DT00097A849https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjvF2rsrc%253D&md5=f96be01c93f0907c1fc9cadd50072bb6Peeling the onion: a revised model of the electron count for matryoshka clustersSheong, Fu Kit; Chen, Wen-Jie; Kim, Hwon; Lin, ZhenyangDalton Transactions (2015), 44 (16), 7251-7257CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)We have provided a model for understanding two isoelectronic matryoshka clusters, [Sn@Cu12@Sn20]12- and [As@Ni12@As20]3-. By dividing each of the clusters in a layer-by-layer manner and allowing each layer to follow a simple electron-filling rule, we can formulate a consistent model to explain exptl. and computed properties of both matryoshka clusters that cannot be adequately explained by existing models. By analyzing these clusters in a way analogous to peeling an onion, we can not only have an understanding of the structure and bonding of the two matryoshka clusters under study, but also have a generalizable model to handle certain p/d-block@d-block endohedral clusters.
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850Baruah, T.; Zope, R. R.; Richardson, S. L.; Pederson, M. R. Electronic structure and rebonding in the onionlike As@Ni12@As20 cluster. Phys. Rev. B: Condens. Matter Mater. Phys. 2003, 68, 241404, DOI: 10.1103/PhysRevB.68.241404850https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmvVahtA%253D%253D&md5=c4824a713f3fd35ebaeb1f62069c962eElectronic structure and rebonding in the onionlike As@Ni12@As20 clusterBaruah, Tunna; Zope, Rajendra R.; Richardson, Steven L.; Pederson, Mark R.Physical Review B: Condensed Matter and Materials Physics (2003), 68 (24), 241404/1-241404/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We present the ab initio study of the geometry, electronic structure, charged states, bonding, and vibrational modes of the recently synthesized fullerene-like As@Ni12@As20 cluster which has icosahedral point symmetry [M. J. Moses, J. C. Fettinger, and B. W. Eichhorn, Science, 300, 778 (2003)]. The mol. is vibrationally stable and will be electronically most stable in its -3 oxidn. state in the condensed phase and in -2 state in the gas phase. We examine the bonding in this unusually structured mol. from charge transfer between atoms, IR and Raman spectra, and charge-d. isosurfaces.
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851Baruah, T.; Zope, R. R.; Richardson, S. L.; Pederson, M. R. Electronic structure, vibrational stability, and predicted infrared-Raman spectra of the As20, As@Ni12, and As@Ni12@As20 clusters. J. Chem. Phys. 2004, 121, 11007– 11015, DOI: 10.1063/1.1803539851https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtVCqtr7O&md5=add147fa69f1b633332d64c38e52a96eElectronic structure, vibrational stability, and predicted infrared-Raman spectra of the As20, As@Ni12, and As@Ni12@As20 clustersBaruah, Tunna; Zope, Rajendra R.; Richardson, Steven L.; Pederson, Mark R.Journal of Chemical Physics (2004), 121 (22), 11007-11015CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Recently an inorg. fulleride-like [As@Ni12@As20]3- onion with near-perfect icosahedral symmetry in the cryst. phase was reported [M. J. Moses, J. C. Fettinger, and B. W. Eichhorn, Science 300, 778(2003)]. This paper presents a detailed computational study in the framework of d. functional theory on various aspects of this mol. The electronic structure of the As@Ni12@As20 is studied in its neutral as well as -3 charged state together with its subunits As20 and As@Ni12 by the all electron linear combination of Gaussian-type orbitals method. The bonding is studied by examg. the integrated charge within at. sphere, the electron localization function, changes in the electron d. distribution, and from vibrational modes. Strong covalent As-As bonds seen in isolated As20 become weaker in the As@Ni12@As20 and strong covalent As-Ni bonds are formed. The structural stability of all 4 clusters is examd. by analyzing the energetics and by calcg. the vibrational frequencies. Further, the IR and Raman spectra is predicted for both the neutral and charged As@Ni12@As20 clusters. Finally, the energy barrier for removal of a single As atom is calcd. for the neutral As@Ni12@As20 cluster.
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852Zhao, J.; Xie, R.-H. Density functional study of onion-skin-like [As@Ni12As20]3– and [Sb@Pd12Sb20]3– cluster ions. Chem. Phys. Lett. 2004, 396, 161– 166, DOI: 10.1016/j.cplett.2004.07.121852https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnsVGqt7o%253D&md5=b385058e13a5075b046fcb04bf83800bDensity functional study of onion-skin-like [As@Ni12As20]3- and [Sb@Pd12Sb20]3- cluster ionsZhao, Jijun; Xie, Rui-HuaChemical Physics Letters (2004), 396 (1-3), 161-166CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)A comprehensive study of the structural and electronic properties of the interesting onion-skin-like [As@Ni12As20]3- cluster ion, characterized by Moses et al. [Science 300 (2003) 778], was carried out using a plane-wave based d. functional theory. The calcd. interat. distances agree well with expt. The HOMO and LUMO for [As@Ni12As20]3- are fivefold-degenerate with hu and hg symmetries, resp., and its HOMO-LUMO gap is detd. to be 0.2 eV lower than that of C60. The static dipole polarizability of [As@Ni12As20]3- is two times larger than that of C60. The optical gap of [As@Ni12As20]3- is red shifted by 1.4 eV relative to that of C60. The possibility of synthesis of [Sb@Pd12Sb20]3- is proposed.
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853Chang, C.; Patzer, A. B. C.; Sedlmayr, E.; Sülzle, D. Inorganic cage molecules encapsulating Kr: A computational study. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 72, 235402, DOI: 10.1103/PhysRevB.72.235402853https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XlvFyltA%253D%253D&md5=1b367599ed958480776f5ad8f5b64349Inorganic cage molecules encapsulating Kr: A computational studyChang, Ch.; Patzer, A. B. C.; Sedlmayr, E.; Sulzle, D.Physical Review B: Condensed Matter and Materials Physics (2005), 72 (23), 235402/1-235402/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Structural and energetic properties of a series of neutral and charged inorg. cage mols. Kr@2@20q (Y = Ni,Pd; Z = As,Sb,Bi; q = 0,-1,-3) where a central krypton atom is encapsulated by two outer cages Y12 and Z20 have been investigated by theor. d. functional techniques (DFT) employing the Becke-Perdew-86 (BP86) gradient cor. exchange correlation functional. The structures are closed shell species representing highly stable local min. of icosahedral point group symmetry Ih. We report energies, equil. geometric parameters, selected harmonic vibrational frequencies, and discuss static elec. dipole polarizabilities. The overall charge q of these cages seems to be controllable by the nature of the central atom leading to stable configurations when Kr is replaced by Br or As. In this context, we report a stable system where a krypton atom is enclosed by a fullerenelike inorg. double cage.
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854Chang, C.; Patzer, A. B. C.; Sedlmayr, E.; Sülzle, D.; Steinke, T. Onion-like inorganic fullerenes of icosahedral symmetry. Comput. Mater. Sci. 2006, 35, 387– 390, DOI: 10.1016/j.commatsci.2004.07.013854https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1OitrjK&md5=8d053f0bef6106112e72369db7985956Onion-like inorganic fullerenes of icosahedral symmetryChang, Ch.; Patzer, A. B. C.; Sedlmayr, E.; Suelzle, D.; Steinke, T.Computational Materials Science (2006), 35 (3), 387-390CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)We report a theor. d. functional study (DFT/BP86/LANL2DZ) of a class of inorg. clusters of formal compn. [X@Y12@Z20]α, which all possess high icosahedral point group symmetry (Ih) consisting of a central atom (X) surrounded by two polyhedral cages: an inner core icosahedron (Y) and an outer shell fullerene-like dodecahedron (Z). All species considered are energetically stable closed-shell systems having a metal/semi-metal compn. Energetic and optimized structural properties as well as a full frequency anal. are presented.
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855Huang, X.; Zhao, J.; Su, Y.; Chen, Z.; King, R. B. Design of three-shell icosahedral Matryoshka clusters A@B12@A20 (A = Sn, Pb; B = Mg, Zn, Cd, Mn).. Sci. Rep. 2015, 4, 6915, DOI: 10.1038/srep06915There is no corresponding record for this reference.
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856King, R. B. Chemical applications of topology and group theory.31. Atomic orbital graphs and the shapes of the g and h orbitals. J. Phys. Chem. A 1997, 101, 4653– 4656, DOI: 10.1021/jp970985f856https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXjs1Wls7k%253D&md5=9e6d0f01113db569f8b24abe732e2094Chemical Applications of Topology and Group Theory. 31. Atomic Orbital Graphs and the Shapes of the g and h OrbitalsKing, R. B.Journal of Physical Chemistry A (1997), 101 (25), 4653-4656CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)AOs, which are described by the quantum nos. n, l, and m, can be depicted by an orbital graph in which the vertices correspond to the lobes of the AOs and the edges to nodes between adjacent lobes of opposite sign. The orbital graph for the unique orbital with m = 0 for a given value of l consists of a linear graph with l + 1 vertices. The orbital graphs for the pair of orbitals with m = ±l consist of polygons with 2l vertices. The orbital graphs for the remaining 2(l - 1) orbitals with 0 < |m| < l consist of a stack of l + 1 - |m| polygons each with |2m| vertices. For a given value of l the AOs with |m| = k and |m'| = l + 1 - k have the same nos. of lobes. Orbital graphs are useful for understanding not only the shapes of AOs of high nodality but also the shapes of the MOs in mols. approximated by a sphere such as the C60 fullerene.
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857Zhang, L.; Huang, J.; Wang, W. Y.; Li, Q. X.; Yang, J. L. Transport properties of a three-shell icosahedral matryoshka cluster: A first-principles study. RSC Adv. 2017, 7, 12704– 12710, DOI: 10.1039/C7RA01003F857https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjt1antrc%253D&md5=6f52b1f51cdebf6609b37a2921b41e0aTransport properties of a three-shell icosahedral matryoshka cluster: a first-principles studyZhang, Lu; Huang, Jing; Wang, Weiyi; Li, Qunxiang; Yang, JinlongRSC Advances (2017), 7 (21), 12704-12710CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Extensive efforts have been devoted to explore transport behaviors through various mols. and clusters, which are promising building blocks in mol. electronics. Here, we examine the spin-polarized electronic structures and transport properties of a three-shell icosahedral matryoshka cluster, Pb@Mn12@Pb20, by performing d. functional theory calcns. combining with non-equil. Green's function method. Theor. results clearly reveal that, twelve Mn atoms in the middle layer anti-ferromagnetically couple with the center Pb atom and Pb atoms in the outlayer, while the Pb@Mn12@Pb20 cluster still has a huge magnetic moment of 28.0μB, mainly contributed by these Mn atoms. The calcd. spin-resolved transmission spectra of the proposed Pb@Mn12@Pb20 junctions exhibit robust spin filtering effect, which is not sensitive to the anchoring distance and the adopted electrode materials, and the conductance through the cluster under the small bias voltage is mainly detd. by the spin-up electrons. These findings indicate that this kind of three-shell matryoshka cluster with huge magnetic moment holds potential applications in mol. spintronic devices.
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858Long, F.; Liu, H.; Li, D.; Yan, J. Spin-orbit coupling effects on ligand-free icosahedral Matryoshka superatoms. J. Phys. Chem. A 2017, 121, 2420– 2428, DOI: 10.1021/acs.jpca.6b12186858https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjt1Grs7s%253D&md5=b1a64bf33f861986038f356b25f3ba2dSpin-Orbit Coupling Effects on Ligand-Free Icosahedral Matryoshka SuperatomsLong, Feiyun; Liu, Haitao; Li, Dafang; Yan, JunJournal of Physical Chemistry A (2017), 121 (12), 2420-2428CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)With the help of d. functional theory, a series of matryoshka superatoms X@Y12@X20 (X = Ge, Y = Zn; X = Sn, Y = Mg, Mn, Zn or Cd; X = Pb, Y = Mg, Mn, Cd, Zn or Hg) with icosahedral symmetry has been extensively studied, to focus on the influence of the spin-orbit coupling on geometries, stabilities, electronic structures and magnetic moments for these clusters. Generally speaking, the effect of spin-orbit coupling is highly correlated with compn. elements of these clusters. Ge@Zn12@Ge20 is little affected by the spin-orbit coupling, while clusters contg. Sn atom will generally undergo a moderate influence on their atomization energy, HOMO-LUMO gap and projected d. of states. For clusters with Pb atoms, the effect of spin-orbit coupling could be obsd. distinctly in most cases. Our results demonstrate that the spin-orbit coupling can play a substantial role in superatoms contg. heavy elements.
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859MacLeod Carey, D.; Morales-Verdejo, C.; Muñoz-Castro, A. [As@Ni12@As20]3– and [Sn@Cu12@Sn20]12– clusters. Related structures with different construction philosophy. Chem. Phys. Lett. 2015, 638, 99– 102, DOI: 10.1016/j.cplett.2015.08.039859https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlyls7jL&md5=7872c58476ba373444fa20f9ae355bed[As@Ni12@As20]3- and [Sn@Cu12@Sn20]12- clusters. Related structures with different construction philosophyMacLeod Carey, Desmond; Morales-Verdejo, Cesar; Munoz-Castro, AlvaroChemical Physics Letters (2015), 638 (), 99-102CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)[Sn@Cu12@Sn20]12- and [As@Ni12@As20]3- structures display highly spherical shapes according to A@B12@A20. Their anal. denote similar features in the electronic structure construction, however the resulting charge distribution exhibits large differences accounting for the different electronic requirements of such concentric structures. This leads to different electronic distribution in the overall system, where the compn. of relevant electronic shells and charge distribution in the whole cluster is an important point to take into account in addn. to well developed electron count rules.
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860Rauhalahti, M.; Munoz-Castro, A. Interaction in multilayer clusters: A theoretical survey of [Sn@Cu12@Sn20]12-, a three-layer matryoshka-like intermetalloid. RSC Adv. 2015, 5, 18782– 18787, DOI: 10.1039/C4RA16660D860https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXit1Gjs7Y%253D&md5=20ded0070ff82aecd2dcc844898d0f22Interaction in multilayer clusters: a theoretical survey of [Sn@Cu12@Sn20]12-, a three-layer matryoshka-like intermetalloidRauhalahti, Markus; Munoz-Castro, AlvaroRSC Advances (2015), 5 (24), 18782-18787CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)[Sn@Cu12@Sn20]12- represents an archetypal intermetalloid structure composed of several concentric polyhedral shells displaying a highly spherical shape. This feature paves the way to understanding the electronic structure of multilayered structures in terms of interacting superat. shells. As a result, [Sn@Cu12@Sn20]12- can be regarded formally as [{Sn@Cu12}4-@{Sn20}8-], which ensures a favorable electronic configuration with a sizable HOMO-LUMO gap for the inner core [Sn@Cu12]4-. The interaction between the [Sn@Cu12]4- and [Sn20]8- layers involves a concentric bonding interaction of s-, p- and d-type. The approach employed here is suggested and demonstrated to be a useful strategy for rationalizing multilayer endohedral clusters, which can be extended to nanoparticles or even to less sym. systems.
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861Damianos, K.; Solokha, P.; Ferrando, R. Core–shell and matryoshka structures in MgNi nanoalloys: A computational study. RSC Adv. 2013, 3, 9419– 9430, DOI: 10.1039/c3ra40861b861https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXot1eitL8%253D&md5=8a7fdc75d56a43b2138dec79c46ad701Core-shell and matryoshka structures in MgNi nanoalloys: a computational studyDamianos, Konstantina; Solokha, Pavlo; Ferrando, RiccardoRSC Advances (2013), 3 (24), 9419-9430CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)The structures of MgNi nanoparticles are searched for by a computational methodol. combining atomistic modeling, global optimization searches and d.-functional theory (DFT) calcns. Sizes of up to 45 atoms are considered for several different compns. Core-shell structures are found in most cases. However, there are also exceptions, such as the three-shell high-symmetry matryoshka clusters Mgi12g32 (of anti-Mackay icosahedral geometry) and Mgi12g14 (of tetrahexahedral geometry). Other high-symmetry structures comprise the core-shell cubic Mg8Ni6, the tetrahexahedral cluster Mg14Ni13 and the pentadocahedral cluster Mg21Ni12. The results of the atomistic models are compared with DFT calcns., obtaining a good agreement.
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862Borbon-Gonzalez, D. J.; Fortunelli, A.; Barcaro, G.; Sementa, L.; Johnston, R. L.; Posada-Amarillas, A. Global minimum Pt13M20 (M = Ag, Au, Cu, Pd) dodecahedral core–shell clusters. J. Phys. Chem. A 2013, 117, 14261– 14266, DOI: 10.1021/jp410079t862https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvV2ku7%252FM&md5=ea9320bfbde7fab7cd71ae545a5292a4Global Minimum Pt13M20 (M = Ag, Au, Cu, Pd) Dodecahedral Core-Shell ClustersBorbon-Gonzalez, Dora J.; Fortunelli, Alessandro; Barcaro, Giovanni; Sementa, Luca; Johnston, Roy L.; Posada-Amarillas, AlvaroJournal of Physical Chemistry A (2013), 117 (51), 14261-14266CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)We report finding dodecahedral core-shell structures as the putative global min. of Pt13M20 (M = Ag, Au, Cu, Pd) clusters by using the basin hopping method and the many-body Gupta model potential to model interat. interactions. These nanoparticles consist of an icosahedral 13-atom platinum core encapsulated by a 20 metal-atom shell exhibiting a dodecahedral geometry (and Ih symmetry). The interaction between the icosahedral platinum core and the dodecahedral shell is analyzed in terms of the increase in vol. of the icosahedral core, and the strength and stickiness of M-Pt and M-M interactions. Low-lying metastable isomers are also obtained. Local relaxations at the DFT level are performed to verify the energetic ordering and stability of the structures predicted by the Gupta potential finding that dodecahedral core-shell structures are indeed the putative global min. for Pt13Ag20 and Pt13Pd20, whereas decahedral structures are obtained as the min. energy configurations for Pt13Au20 and Pt13Cu20 clusters.
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863Wang, J. L.; Bai, J. L.; Jellinek, J.; Zeng, X. C. Gold-coated transition-metal anion [Mn13@Au20]- with ultrahigh magnetic moment. J. Am. Chem. Soc. 2007, 129, 4110– 4111, DOI: 10.1021/ja0664234863https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXivF2jsbo%253D&md5=98146ef6a0510e484f5aafa72aa89583Gold-Coated Transition-Metal Anion [Mn13@Au20]- with Ultrahigh Magnetic MomentWang, Jinlan; Bai, Jaeil; Jellinek, Julius; Zeng, Xiao ChengJournal of the American Chemical Society (2007), 129 (14), 4110-4111CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors presented results of DFT computations which show that coating magnetic clusters with gold can both enhance (as in the case of [Mn13@Au20]-) and attenuate (as in the case of [Co13@Au20]-) the net magnetic moment of the clusters. The degree of magnetic enhancement for (Mn13@Au20)- (44 μB) as well as the cluster's bistability at both low (2 μB) and high (44 μB) spin states suggests that the gold coated manganese clusters may be good prototype systems for nanomagnetism applications.
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864Bai, X.; Lv, J.; Wu, H.-S. A giant enhancement of magnetic moment in a ternary three-shell icosahedral cluster: Fe@Mn12@Au20. Mol. Phys. 2020, 118, 1– 7, DOI: 10.1080/00268976.2019.1659434There is no corresponding record for this reference.
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865Kou, C. Y.; Zhuang, L.; Wang, G. Q.; Cui, H.; Yuan, H. K.; Tian, C. L.; Wang, J. Z.; Chen, H. [TM13@Bi20]- clusters in three-shell icosahedral matryoshka structure: Being as superatoms. RSC Adv. 2015, 5, 92134– 92143, DOI: 10.1039/C5RA19194G865https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12ksb%252FF&md5=901fdab710803bed6dde00685573156c[TM13@Bi20]- clusters in three-shell icosahedral matryoshka structure: being as superatomsKou, C. Y.; Zhuang, L.; Wang, G. Q.; Cui, H.; Yuan, H. K.; Tian, C. L.; Wang, J. Z.; Chen, H.RSC Advances (2015), 5 (112), 92134-92143CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)Using the d. functional theory (DFT) method, the 33-atom intermetalloid [TM13@Bi20]- clusters (TM = 3d, 4d), which are composed of Bi20 pentagonal dodecahedra surrounding TM12 icosahedra with a single TM atom at the center, have been systematically examd. to explore the possibility of clusters being as superatoms. The results show that most TM13 clusters can be attractively encapsulated into Bi20 cage to form a stable core-shell configuration, exhibiting an interesting progression of thermal stability along the 3d and 4d periods. Taking into account the structural stability (binding energy, embedding energy, and core-shell interaction) as well as the chem. stability (HOMO-LUMO gap), we proposed that [TM13@Bi20]- clusters with Ti and Mn doping in 3d series (Zr and Ag doping in 4d series) are specially stable and to be the protyle superatoms. For such systems, the MO shapes and energy alignments are in analogy with the at. patterns, coinciding the general characters of superat. orbitals. The closed core superat. shell together with the partially-filled valence superat. shell configuration leads to magnetic moment in stable [TM13@Bi20]-, e.g., [Mn13@Bi20]- cluster with the half-filled subshell can be assigned as a magnetic superatom owning to its modest HOMO-LUMO gap of 0.37 eV and large magnetic moment of 36 μB. The exchange-splitting in TM-3d states is found to be the driving force for the improvement of exchange-splitting of superat. states.
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866Sigmon, G. E.; Ling, J.; Unruh, D. K.; Moore-Shay, L.; Ward, M.; Weaver, B.; Burns, P. C. Uranyl–peroxide interactions favor nanocluster self-assembly. J. Am. Chem. Soc. 2009, 131, 16648– 16649, DOI: 10.1021/ja907837u866https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtleksb7K&md5=bfb58acf39d85f61972354d7bc351f62Uranyl-Peroxide Interactions Favor Nanocluster Self-AssemblySigmon, Ginger E.; Ling, Jie; Unruh, Daniel K.; Moore-Shay, Laura; Ward, Matthew; Weaver, Brittany; Burns, Peter C.Journal of the American Chemical Society (2009), 131 (46), 16648-16649CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)[(UO2)20(O2)30]20-, a cluster contg. 20 uranyl pentagonal triperoxides, was isolated in the compd. Na11(N(C3H7)4)9[(UO2)20(O2)30]·9H2O and characterized assuming the smallest possible fullerene topol. consisting only of 12 pentagons. It is the only fullerene isomer with 20 vertices. Oxalate was used to crystallize fragments of larger uranyl peroxide clusters, and these fragments and other known structures indicate that the U-O2-U dihedral angle is inherently bent. Such bending probably is essential in directing the self-assembly of uranyl peroxide polyhedra into closed clusters.
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867Hu, H. S.; Kaltsoyannis, N. High spin ground states in Matryoshka actinide nanoclusters: A computational study. Chem. - Eur. J. 2018, 24, 347– 350, DOI: 10.1002/chem.201705196867https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFegu7nL&md5=5bf32dedf4148fa8bb09de849dcc2ef6High Spin Ground States in Matryoshka Actinide Nanoclusters: A Computational StudyHu, Han-Shi; Kaltsoyannis, NikolasChemistry - A European Journal (2018), 24 (2), 347-350CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)Inspired by the exptl. synthesized Na12@[(UO2)(O2)1.5]208- ("Na12@U20") cluster, we have explored computationally the substitution of the Na cations by many other metals. 6 other M12@U20 systems are found to be stable (M=K+, Rb+, Cs+, Ag+, Mg2+, Fe2+). For 3 of these (Mg2+, Ag+ and Na+), the cluster can support a group 16 dianion at its center, forming a new type of Matryoshka ("Russian Doll") actinide nanocluster E@M12@U20 (E=S2-, Se2-, Te2-, and Po2-). These systems have 3-shell, onion-like geometries with nearly perfect Ih symmetry. Seeking to create clusters with very high spin ground states, we have replaced M by Mn2+ and U20 by Np20 and Pu20, generating clusters with max. possible S values of 80/2 and 100/2 resp. Only in the presence of a central S2-, however, are these electronic configurations the most stable; the novel Matryoshka Pu nanocluster S@Mn12@Pu20 is predicted to have the highest ground state spin yet reported for a mol. cluster.
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868Zhao, J.; Wang, X.; Zhao, J.; Luo, R.; Shen, X.; Zhu, D.; Jing, S. [Ln4@Ln4] matryoshka tetrahedron: A novel secondary building unit. CrystEngComm 2016, 18, 863– 867, DOI: 10.1039/C5CE02417J868https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitV2msbjL&md5=334b8e6311b63a7e6b234c0f010ce131[Ln4@Ln4] matryoshka tetrahedron: a novel secondary building unitZhao, Jie; Wang, Xin; Zhao, Jing; Luo, Rui; Shen, Xuan; Zhu, Dunru; Jing, SuCrystEngComm (2016), 18 (6), 863-867CODEN: CRECF4; ISSN:1466-8033. (Royal Society of Chemistry)A novel secondary building unit, a Russian nesting doll [Ln4@Ln4] tetrahedron, was developed for building metal-org. frameworks, [Ln2(μ3-OH)L2.5(H2O)2]·0.5DMF (Ln = Eu, Gd, Dy, H2L = 2,2'-dimethoxy-4,4'-biphenyldicarboxylic acid), with an unprecedented binodal (3,20)-connected 3-dimensional network by using a linear bridge-linking ligand. The photoluminescence of the Eu MOF and magnetic properties of the Gd and Dy MOFs were studied.
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869Iwasa, T.; Nakajima, A. Geometric, electronic, and optical properties of monomer and assembly of endohedral aluminum superatomic clusters. J. Phys. Chem. C 2013, 117, 21551– 21557, DOI: 10.1021/jp406054k869https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsFGrs7bK&md5=7611f2682dd66b689b59c0acb475636fGeometric, Electronic, and Optical Properties of Monomer and Assembly of Endohedral Aluminum Superatomic ClustersIwasa, Takeshi; Nakajima, AtsushiJournal of Physical Chemistry C (2013), 117 (41), 21551-21557CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)D. functional computations are used to evaluate the geometric, electronic, and optical properties of endohedral Al clusters X@Al12 (X = B, Al, Si, P) and their assemblies. All X@Al12+/0/- clusters are perfect or slightly distorted icosahedral structures, with the exception of Al13+, which is highly distorted. The projected d. of states (PDOS) onto the spherical harmonics of monomers clearly reveals superatom behavior and electron shell closings of F orbitals in a 40-electron species. The electronic absorption spectrum of SiAl12 is analyzed in terms of the superatom orbitals. The optimized structures of X@Al12-Y@Al12 (X-Y = Si-Si, B-P, Al-P) dimers are constructed by facing the sides of the monomers in a staggered fashion. The PDOS of the dimers mostly exhibit 5 hybridizations: S, P, SD, PF, and SDG. The exceptions are HOMO, which possesses a DFG hybridized character and lies between the PF and SDG regions, and LUMO, which possesses a DG hybridized character. By analyzing the simulated absorption spectra of the B@Al12-P@Al12 and Al13-P@Al12 heterodimers, charge transfers from B/Al@Al12 to P@Al12 are found in the visible region, weakly accompanying the opposite charge transfer. 7. The heterodimers have substantial charge carriers, estd. as the difference in electron counts from the closed-shell Si@Al12, with slight charge depletions (∼0.2). The charge distributions in B@Al12 and P@Al12 are essentially unaltered by the insertion of Si@Al12 into the heterodimer, resulting in that the heterotrimer possesses a larger dipole moment than the heterodimer.
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870Sun, Q.; Wang, Q.; Briere, T.; Kawazoe, Y. Dimer interactions of magic W@Si12 clusters. J. Phys.: Condens. Matter 2002, 14, 4503– 4508, DOI: 10.1088/0953-8984/14/17/320870https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktFSnsbY%253D&md5=8d79efe2aa3a2a8ffeb4217014fb5a43Dimer interactions of magic W@Si12 clustersSun, Q.; Wang, Q.; Briere, T. M.; Kawazoe, Y.Journal of Physics: Condensed Matter (2002), 14 (17), 4503-4508CODEN: JCOMEL; ISSN:0953-8984. (Institute of Physics Publishing)The authors explored the possibility of constructing a Si nanotube by using the metal-stabilized and tube-shaped Si cluster W@Si12 as a basic unit and present detailed B3LYP-DFT calcns. of the interactions. of the dimers. The interactions are orientation dependent, and no interactions exist if the stacking is along the sixfold axis. The W atom can be used as a spacer to link the two units, resulting in a metastable structure. Due to the large surface stress in such a small one-dimensional system, sixfold stacking cannot be extended, and thus the trimer is not dynamically stable. Further, the most stable geometry for the dimer is seriously distorted. Consequently, it is difficult to construct a Si nanotube using this W@Si12 tube-shaped unit.
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871Robles, R.; Khanna, S. N. Magnetism in assembled and supported silicon endohedral cages: First-principles electronic structure calculations. Phys. Rev. B: Condens. Matter Mater. Phys. 2009, 80, 115414, DOI: 10.1103/PhysRevB.80.115414871https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht1agtrnK&md5=5480f6edddb22b4ea045f3bf2b176d9aMagnetism in assembled and supported silicon endohedral cages: First-principles electronic structure calculationsRobles, R.; Khanna, S. N.Physical Review B: Condensed Matter and Materials Physics (2009), 80 (11), 115414/1-115414/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)First principles electronic structure calcns. on a free CrSi12 cluster, a (CrSi12)2 dimer, and CrSi12 clusters supported on Si(111) surfaces have been carried out within a gradient cor. d. functional formalism using a supercell approach. The ground state of CrSi12 is a Cr centered hexagonal biprism of Si atoms in which the Cr spin moment is completely quenched. As two CrSi12 motifs are brought together, they form different composite units depending on initial direction of approach and, in most cases, the composite cluster is found to have a net spin moment. Cluster assemblies obtained by depositing CrSi12 motifs on a Si(111) surface exhibit similar finite spin moments for several initial directions of approach. An anal. of the electronic states shows that the origin of the magnetic moment lies in those Cr d-states that do not mix with silicon sp states. The studies suggest the possibility of forming silicon-based magnetic semiconductors through such assemblies.
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872Torres, M.; Fernández, E.; Balbás, L. Study of the structural and electronic properties of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n (n ≤ 9) aggregates from first principles. J. Phys. Chem. C 2011, 115, 335– 350, DOI: 10.1021/jp1066742872https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhs1SrsbrE&md5=0db995484866055a98c9064dec1d56a6Study of the Structural and Electronic Properties of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n (n ≤ 9) Aggregates from First PrinciplesTorres, M. B.; Fernandez, E. M.; Balbas, L. C.Journal of Physical Chemistry C (2011), 115 (2), 335-350CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Recent exptl. and theor. work has established that the ground state and low-lying energy isomers of endohedral M@Si16 clusters (M = Sc-, Ti, or V+) have a nearly spherical cagelike form, an at.-like closed shell electronic structure, and a large HOMO-LUMO gap of ∼2 eV, which suggests the use of these clusters as basic units (superatoms) in the assembly of optoelectronic materials. As a first step in that direction, in this work are studied, by means of first-principles DFT-PBE calcns., the trends in the formation of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n aggregates as their sizes increase (n ≤ 9). We identify esp. stable linear, planar, and three-dimensional patterns that can be used to grow low-dimensional periodical systems. When n ≥ 2, the aggregates with greater binding energy result from the bonding of n supermol. units having D4d symmetry for the M@Si16 cage, instead of the Frank-Kasper symmetry ground state of the basic superatom. Particularly interesting aggregates are (i) [Ti@Si16]n rings when n ≥ 6, which can be grown as wires or nanotubes; (ii) rings and linear forms of [Sc@Si16K]n aggregates having a rich variety of nearly degenerate isomers differing in the bonding site of K atoms and strongly varying elec. dipole moments; and (iii) [M@Si16X]3m wires (m = 1-3) formed by vertically stacking the [M@Si16X]3 starlike trimer with rotation of 60° between consecutive trimer units, which show interesting magnetic configurations for M = V and X = F. The HOMO-LUMO gap for the most favorable structure decreases with size, and the aggregates become nearly metallic when n ≤ 9.
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873Iwasa, T.; Nakajima, A. Geometric, electronic, and optical properties of a superatomic heterodimer and trimer: Sc@Si16–V@Si16 and Sc@Si16–Ti@Si16–V@Si16. J. Phys. Chem. C 2012, 116, 14071– 14077, DOI: 10.1021/jp302752g873https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XovFaqs7c%253D&md5=b5b9ded829bd55de94d0e8bc8730a6edGeometric, Electronic, and Optical Properties of a Superatomic Heterodimer and Trimer: Sc@Si16-V@Si16 and Sc@Si16-Ti@Si16-V@Si16Iwasa, Takeshi; Nakajima, AtsushiJournal of Physical Chemistry C (2012), 116 (26), 14071-14077CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The geometric, electronic, and optical properties of a heterodimer and trimer consisting of metal-encapsulating silicon cage clusters, M@Si16 (M = Sc, Ti, V) with D4d symmetry, were studied using the DFT-CAM-B3LYP method to explore the possibility of using these clusters as building blocks for a nanometer scale heteroassembly. Among the possible low-lying geometries, the linear-form of the hetero-oligomers was adopted as a model system, where the D4d monomers are covalently bonded by facing their squares in an eclipsed fashion. The heterodimer consisting of halogen-like Sc@Si16 and alk.-like V@Si16 has a dipole moment of 7.63 D, and its occupied and virtual frontier orbitals are localized to V@Si16 and to Sc@Si16, resp. Some of the inner MOs exhibit superat. bonding and antibonding character. The electronic excitations involve charge-transfer states mainly from V@Si16 to Sc@Si16 in the optical energy region. The linear heterotrimer of Sc@Si16-Ti@Si16-V@Si16, formed by inserting the rare-gas-like Ti@Si16, has a larger dipole moment of 15.6 D and one or more localized frontier orbitals compared to the dimer. We propose possible formation routes to realize the present hetero-oligomers using photoexcitation or energy-selective electron injection into several LUMOs of the monomers that are suitable for linear-oligomerization.
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874Liu, J.; Guo, P.; Zheng, J.; Zhao, P.; Jiang, Z.; Shen, L. Self-assembly of a two-dimensional sheet with Ta@Si16 superatoms and its magnetic and photocatalytic properties. J. Phys. Chem. C 2020, 124, 6861– 6870, DOI: 10.1021/acs.jpcc.9b10196874https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXnslyjuw%253D%253D&md5=89662a72be024c0ecce38a2deb8274d8Self-Assembly of a Two-Dimensional Sheet with Ta@Si16 Superatoms and Its Magnetic and Photocatalytic PropertiesLiu, Jia; Guo, Ping; Zheng, Jiming; Zhao, Puju; Jiang, Zhenyi; Shen, LeiJournal of Physical Chemistry C (2020), 124 (12), 6861-6870CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The development of new functional materials with a rational design, controllable assembly, and tunable property is highly demanded. Here, we take the exptl. synthesized Ta@Si16 superatom as a building block to design several low-lying Ta@Si16 dimers and self-assembled two-dimensional (2D) sheets, and then study their structural stability and magnetic and photocatalytic properties as well as potential applications by d. functional theory and mol. dynamics. Our results show that the Ta@Si16 superatom can maintain its cage frame of geometric structure in all of these self-assembled structures at room temp. It is found that the honeycomb hexagonal lattice Hex-d structure, the line-contact and the face-contact Ta@Si16/C60 interfacial structures are three new semiconductors with band gaps of 0.89, 0.43, and 1.32 eV, resp. As an intrinsic ferromagnet, the line-contact Ta@Si16/C60 structure has a Curie temp. of 294 K. Furthermore, our study shows that the face-contact Ta@Si16/C60 one might be a good photocatalyst.
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875Park, S.; Kim, G.; Kwon, Y.-K. First-principles investigation on dimerization of metal-encapsulated gold nanoclusters. RSC Adv. 2014, 4, 192– 198, DOI: 10.1039/C3RA45742G875https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVeisrjF&md5=bba730142fde70ab5be4f775e6ae728aFirst-principles investigation on dimerization of metal-encapsulated gold nanoclustersPark, Sora; Kim, Gunn; Kwon, Young-KyunRSC Advances (2014), 4 (1), 192-198CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)D. functional theory is used to study dimerization of metal-encapsulated gold nanoclusters M@Au12 (M = W, Mo) with Ih or Oh symmetry, and their structural and electronic properties. To det. the most stable dimer structure in each case, various configurations are considered. We find that during dimerization, gold atoms near the interface tend to form inter-cluster triangular bonds, which stabilize two monomer clusters by about 3.3-3.5 eV. The dimerization along a specific axis selected as the z axis causes the symmetry redn. of each M@Au12 cluster resulting in the modification of electronic structures. It is found that all the stable dimers exhibit a much smaller HOMO-LUMO gap than those of their comprising monomers. Such a gap decrease is mainly attributed to the dz2 orbital splitting of the central atoms owing to dimerization. We also calc. the vibrational modes and the corresponding IR-active spectra, which are distinguishable for different dimer configurations. In addn., we find that the IR-active modes of the Oh-based dimer structures appear to be red-shifted in comparison to those of Ih-based ones. Thus, the IR spectra may be utilized exptl. to discriminate dimer configurations with different central metal atoms and/or dissimilar structural symmetries.
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876Kumar, V. Predictions of novel nanostructures of silicon by metal encapsulation. Comput. Mater. Sci. 2004, 30, 260– 268, DOI: 10.1016/j.commatsci.2004.03.012876https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXlvVeitro%253D&md5=84eda250127f3caf9b47b4ae218e127bPredictions of novel nanostructures of silicon by metal encapsulationKumar, VijayComputational Materials Science (2004), 30 (3-4), 260-268CODEN: CMMSEM; ISSN:0927-0256. (Elsevier Science B.V.)Recent studies using ab initio total energy calcns. have shown exciting possibilities of developing novel metal encapsulated caged clusters of silicon with fullerene-like, Frank-Kasper and other polyhedral structures. In contrast to carbon for which empty cage fullerene structures are stable with 20 or more atoms, 10-16 atom silicon cage structures are stabilized by a guest metal atom. These nanoclusters are predicted to exhibit luminescence in the visible range and could find applications in biol. systems, optoelectronics, and as tagging material. The Raman and IR spectra have been calcd. and they could help in the exptl. identification of the structures. Interaction of these clusters with metal as well as oxygen or hydrogen atoms show that the fullerene structure is stable. Also the interaction between clusters themselves is weak and the ionization potentials, large. These properties make them attractive for cluster assembled materials such as nanowires, nanotubes, and other 2 and 3D structures. Studies on hydrogen interaction have led to the predictions of empty center hydrogenated silicon fullerenes SinHn with large HOMO-LUMO gaps. These could further be doped endohedrally or exohedrally to produce novel silicon fullerenes with a variety of properties opening new ways of using silicon for diverse applications.
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877Kumar, V. Recent theoretical progress on electronic and structural properties of clusters: Permanent electric dipoles, magnetism, novel caged structures, and their assemblies. Comput. Mater. Sci. 2006, 35, 375– 381, DOI: 10.1016/j.commatsci.2004.10.012877https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1OitrjI&md5=914a64c6e52f5a485756c7af6faa92d0Recent theoretical progress on electronic and structural properties of clusters: Permanent electric dipoles, magnetism, novel caged structures, and their assembliesKumar, VijayComputational Materials Science (2006), 35 (3), 375-381CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)A review. We present a brief account of the recent progress in the theor. understanding of the electronic and structural properties of clusters of metals and semiconductors from ab initio calcns. The origin of the recently obsd. permanent elec. dipoles in Nb clusters, the occurrence of magnetism in clusters of non-magnetic elements such as Pd, Rh, and Ru, as well as the findings of the metal encapsulated clusters of Si, Ge, Sn, and Pb are discussed. Empty caged clusters of Si, Ge, and Sn have also been shown to be stable with H capping. These can be functionalized by exohedral doping for different applications while endohedral doping of the cages can be used to tailor highest occupied-LUMO gaps as well as the magnetic properties. Assemblies of such clusters could lead to novel nanostructures and new phases of these materials.
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878Reber, A. C.; Khanna, S. N.; Castleman, A. W. Superatom compounds, clusters, and assemblies: Ultra alkali motifs and architectures. J. Am. Chem. Soc. 2007, 129, 10189– 10194, DOI: 10.1021/ja071647n878https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXotFGnsb0%253D&md5=6d75258cf5c0b8bdd42c9cd97adca8e8Superatom Compounds, Clusters, and Assemblies: Ultra Alkali Motifs and ArchitecturesReber, Arthur C.; Khanna, Shiv N.; Castleman, A. Welford, Jr.Journal of the American Chemical Society (2007), 129 (33), 10189-10194CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)It has recently been demonstrated that chosen clusters of specific size and compn. can exhibit behaviors reminiscent of atoms in the periodic table and hence can be regarded as superatoms forming a third dimension. An Al13 cluster has been shown to mimic the behavior of halogen atoms. Here, we demonstrate that superatom compds. formed by combining superhalogens (Al13) with superalkalis (K3O and Na3O) can exhibit novel chem. and tunable electronic features. For example, Al13(K3O)3 is shown to have low first and second ionization potentials of 2.49 and 4.64 eV, resp., which are lower than alkali atoms and can be regarded as ultra alkali motifs. Al13K3O is shown to be a strongly bound mol. that can be assembled into stable superatom assemblies (Al13K3O)n with Al13 and K3O as the superatom building blocks. The studies illustrate the potential of creating new materials with an unprecedented control on phys. and electronic properties.
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879Reveles, J.; Baruah, T.; Zope, R. R. Al12Cu Superatom as stable building block of ionic salts. J. Phys. Chem. C 2015, 119, 5129– 5137, DOI: 10.1021/jp512261v879https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVeqs7o%253D&md5=f607957646410b4e9fd5112af46a561fAl12Cu Superatom as Stable Building Block of Ionic SaltsReveles, J. U.; Baruah, Tunna; Zope, Rajendra R.Journal of Physical Chemistry C (2015), 119 (9), 5129-5137CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The neutral copper aluminum cluster complex Al12CuM3 [M = K, K3O, and K(2,2,2-crypt)] has been investigated at the PBE96 level of theory. It is found that Al12Cu could be considered a superatom mimic of a phosphorus atom. It shows large electron affinity and is able to receive three electrons from elements or compds. with low ionization energies like K, K3O, or K(2,2,2-crypt) to become a stable electronic closed shell with a large gap between the highest occupied and lowest unoccupied MOs (HOMO-LUMO gap). Theor. calcns. confirm that similar to the phosphorus atom in PK3, the superatom Al12Cu cluster could form ionic salts, as shown from stable dimers, trimers, and tetramers of the Al12Cu{K(2,2,2-crypt)}3 complex. On the basis of the maintenance of its integrity in these assemblies it could be predicted that Al12CuM3 holds great potential as a building block for the development of future nanostructured materials. Furthermore, the choice of the K(2,2,2-crypt) mols. to stabilize the salt opens a route to exptl. generate cluster base ionic salts, and we expect that our work motivates exptl. investigations of these assemblies.
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880Okada, N.; Uchida, N.; Kanayama, T. Thermal stability of amorphous Si-rich W silicide films composed of W-atom-encapsulated Si clusters. J. Appl. Phys. 2017, 121, 225308, DOI: 10.1063/1.4985248880https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVWjtr3I&md5=6078b79b97cc77a6e3ab6734ce082ae7Thermal stability of amorphous Si-rich W silicide films composed of W-atom-encapsulated Si clustersOkada, Naoya; Uchida, Noriyuki; Kanayama, ToshihikoJournal of Applied Physics (Melville, NY, United States) (2017), 121 (22), 225308/1-225308/5CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)The excellent thermal stability of an amorphous film composed of W atom-encapsulated Si (WSin) clusters with n ≥8, formed by thermal deposition using WF6 and SiH4 gases, was demonstrated. To det. how the structure of the constituting clusters affected film thermal stability, films contg. un-encapsulated WSin clusters where the W atom was not fully encapsulated in the Sin cage, with n ≤7, were prepd. Annealing effect was examd. by Raman scattering and optical absorption measurements with repeated 10-min isochronal annealing in a N2 atmosphere at 500-1100°. Films composed of WSin clusters completely encapsulating W atoms with a uniform compn. of n = 12 remained in the same amorphous structure up to 1000°, although partial crystn. of Si began at 1100°. Stability decreased when the film contained un-encapsulated WSin clusters, even with an av. film compn. of n ≤10; partial crystn. of Si and WSi2 was obsd. after annealing at 800°. D. functional theory calcns. indicated a structure assembled from three encapsulated WSi12 clusters preserves the bonding topol. of the constituting clusters where Si atoms are strongly bonded, and accounted for the high thermal stability of the film composed of encapsulated WSin clusters. (c) 2017 American Institute of Physics.
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881Torres, M.; Fernández, E.; Balbás, L. Theoretical study of the structural and electronic properties of aggregates, wires, and bulk phases formed from M@Si16 superatoms (M = Sc–, Ti, V+). Int. J. Quantum Chem. 2011, 111, 444– 462, DOI: 10.1002/qua.22750881https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVGkt7zP&md5=06006e48323f62805ea9855bb1e4a5f3Theoretical study of the structural and electronic properties of aggregates, wires, and bulk phases formed from M = Si16 superatoms (M = Sc-, Ti, V+)Torres, M. B.; Fernandez, E. M.; Balbas, L. C.International Journal of Quantum Chemistry (2011), 111 (2), 444-462CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)Starting with the nearly spherical endohedral M@Si16 cage-like clusters (M = Sc-, Ti, V+) in their fullerene-like isomerical form with D4d symmetry, we study the trends in the formation of [Ti@Si16]n, [Sc@Si16K]n, and [V@Si16F]n aggregates as their size increase (n ≤ 9). We identify specially stable linear, planar, and three-dimensional patterns, which can serve to grow low-dimensional infinite systems. The structure and cohesive energy of a few infinite chains of that type are optimized. We also present calcns. of fcc, bcc, and single cubic crystal meta stable phases having the Ti@Si16 superatom as basic unit, as well as cubic NaCl and CsCl bulk structures of Sc@Si16K and V@Si16F supermols. The orientation and isomerization of the superatom or supermol. in the cubic cell plays an important role. The projected d. of states of V@Si16F crystal with NaCl structure shows a meta stable ferromagnetic phase due to polarization of d electrons of vanadium. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011.
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882Singh, A. K.; Kumar, V.; Briere, T. M.; Kawazoe, Y. Cluster assembled metal encapsulated thin nanotubes of silicon. Nano Lett. 2002, 2, 1243– 1248, DOI: 10.1021/nl025789l882https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvFWnsb8%253D&md5=359b6860f413860e5431730df67f1d15Cluster Assembled Metal Encapsulated Thin Nanotubes of SiliconSingh, Abhishek Kumar; Kumar, Vijay; Briere, Tina M.; Kawazoe, YoshiyukiNano Letters (2002), 2 (11), 1243-1248CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Using ab initio total energy calcns. the recently found metal encapsulated silicon clusters Si12Be can be assembled to form hexagonal nanotubes of silicon. This is in contrast to undoped silicon structures that are distorted and have a tendency to agglomerate. The finite nanotubes have varying HOMO-LUMO gaps depending upon the length and amt. of doping. However, infinite nanotubes are metallic, sym., and stable, making metal encapsulation a useful route to generate metallic silicon nanowires for miniature devices.
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883Menon, M.; Andriotis, A. N.; Froudakis, G. Structure and stability of Ni-encapsulated Si nanotube. Nano Lett. 2002, 2, 301– 304, DOI: 10.1021/nl015695w883https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XhtVKhtLc%253D&md5=795ffdca385f907d9ecfd0e9f9a7d3d0Structure and Stability of Ni-Encapsulated Si NanotubeMenon, Madhu; Andriotis, Antonis N.; Froudakis, GeorgeNano Letters (2002), 2 (4), 301-304CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Using tight-binding mol. dynamics and ab initio methods, we predict the existence of a novel quasi-one-dimensional Ni-Si form in which a Si nanotube is stabilized by an encapsulation of the Ni chain. The resulting structure is found to be metallic with finite DOS at the Fermi level. Our work follows the recent exptl. work showing that endohedral encapsulation of transition metal atoms stabilizes the Si polyhedral cage.
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884Andriotis, A. N.; Mpourmpakis, G.; Froudakis, G. E.; Menon, M. Stabilization of Si-based cage clusters and nanotubes by encapsulation of transition metal atoms. New J. Phys. 2002, 4, 78, DOI: 10.1088/1367-2630/4/1/378There is no corresponding record for this reference.
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885Mpourmpakis, G.; Froudakis, G. E.; Andriotis, A. N.; Menon, M. Understanding the structure of metal encapsulated Si cages and nanotubes: Role of symmetry and d-band filling. J. Chem. Phys. 2003, 119, 7498– 7502, DOI: 10.1063/1.1607309885https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXns1Gntbk%253D&md5=7c3e475b69cf35ce0078fdf0ef72424aUnderstanding the structure of metal encapsulated Si cages and nanotubes: Role of symmetry and d-band fillingMpourmpakis, Giannis; Froudakis, George E.; Andriotis, Antonis N.; Menon, MadhuJournal of Chemical Physics (2003), 119 (14), 7498-7502CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)Using the B3LYP-DFT method we studied the stability of Si-based cages and nanotubes stabilized by encapsulated transition metal atoms (TMAs). The stabilization of these cages and nanotubes as well as their magnetic properties are strongly dependent on a delicate interplay between the attainable symmetry of the system and the d-band filling of the encapsulated TMA. As a result, encapsulated TMAs of the early 3-d series lead to tubular structures of C6 symmetry and antiferromagnetic alignment between the magnetic moment of the TMA and that of the Si atoms. On the other hand, the encapsulated late 3-d elements lead to tubules of the C5 symmetry and to a ferromagnetic alignment of the metal and Si magnetic moments. Encapsulated Fe atoms (being near the middle of the 3-d series) lead to tubular structures of either C6 or C5 symmetry.
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886Tan Pham, H.; Minh Tam, N.; Van Duong, L.; Phuong Pham-Ho, M.; Tho Nguyen, M. Mn2@Si15: The smallest triple ring tubular silicon cluster. Phys. Chem. Chem. Phys. 2015, 17, 17566– 17570, DOI: 10.1039/C5CP02257FThere is no corresponding record for this reference.
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887Wei-xiao, J.; Chenglin, L. Density-functional investigation of hexagonal prism transition-metal-encapsulated cage M2Si18 (M = Sc–Zn) clusters. Modell. Simul. Mater. Sci. Eng. 2010, 18, 025011, DOI: 10.1088/0965-0393/18/2/025011There is no corresponding record for this reference.
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888Ji, W.; Luo, C. Structures, magnetic properties, and electronic counting rule of metals-encapsulated cage-like M2Si18 (M = Ti-Zn) clusters. Int. J. Quantum Chem. 2012, 112, 2525– 2531, DOI: 10.1002/qua.23245888https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtl2gsLvM&md5=cfa8d3dbdc080d40946ced9880f1b0f4Structures, magnetic properties, and electronic counting rule of metals-encapsulated cage-like M2 Si18 (M = Ti-Zn) clustersJi, Weixiao; Luo, ChenglinInternational Journal of Quantum Chemistry (2012), 112 (12), 2525-2531CODEN: IJQCB2; ISSN:0020-7608. (John Wiley & Sons, Inc.)The geometries, magnetic properties and stabilities of the transition metal (TM) atoms encapsulated M2Si18 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) clusters have been systematically calcd. by using the d. function theory with generalized gradient approxn. Only when the doping metal atom has no more than half-full d electronic shell, a double hexagonal prism cage-like M2Si18 structure could form. The total moments of M2Si18 are either 0 or 2μB. Co2Si18 is the most stable cluster among all 3d doped M2Si18 clusters. The model of shell closure at the TM atom may be helpful to understand the stability of M2Si18 clusters. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011.
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889Nayak, S.; Gruner, M.; Entel, P. Possible one-dimensional structures obtained from transition metal atom doped silicon nanoclusters. Phase Transitions 2006, 79, 709– 716, DOI: 10.1080/01411590601030217889https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXpt1CnsA%253D%253D&md5=94ae19a6c079aa3a83f202afb49f6423Possible one-dimensional structures obtained from transition metal atom doped silicon nanoclustersNayak, S. K.; Gruner, M. E.; Entel, P.Phase Transitions (2006), 79 (9-10), 709-716CODEN: PHTRDP; ISSN:0141-1594. (Taylor & Francis Ltd.)Silicon clusters doped with transition metal (TM) atoms show profound stability and prefer endohedral encapsulation of TM atoms. The early 3d elements (M) adopt the D6h symmetry for Si12M, while the late 3d elements acquire the D5h symmetry for Si10M clusters. The central 3d element stabilizes both types of clusters. The silicon atoms attain an induced magnetic moment from the TM atom which gives rise to a broad spectrum of magnetic behavior in these clusters depending on M. Suitable stacking of clusters along the direction perpendicular to their plane of symmetry is a possible route to grow one-dimensional structures like nanorods and nanowires. Calcns. with the DFT-GGA method are performed to study the above aspect for transition metal atom doped silicon clusters.
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890Wang, J.; Zhao, J.; Ma, L.; Wang, G.; King, R. B. Stability and magnetic properties of Fe encapsulating in silicon nanotubes. Nanotechnology 2007, 18, 235705, DOI: 10.1088/0957-4484/18/23/235705890https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXosVehtrk%253D&md5=560956f7754662cea56cb54e6bdb153cStability and magnetic properties of Fe encapsulating in silicon nanotubesWang, Jianguang; Zhao, Jijun; Ma, Li; Wang, Guanghou; King, R. BruceNanotechnology (2007), 18 (23), 235705/1-235705/8CODEN: NNOTER; ISSN:0957-4484. (Institute of Physics Publishing)Using all-electron d. functional theory with gradient correction, we have investigated the stability of quasi-one-dimensional tubular nanostructures by stacking the pentagonal FeSi10 prism and hexagonal FeSi12 prism along their axes. The local magnetic moments on Fe atoms in finite hexagonal nanotubes increase linearly with tube length, whereas the magnetism in most finite pentagonal nanotubes are quenched owing to the charge transfer and strong hybridization between 4s and 3d states of Fe and 3s and 3p states of Si. The infinite hexagonal nanotube with stoichiometry of FeSi6 is found to be ferromagnetic with magnetic moment per Fe atom comparable to the bulk value. Both pentagonal and hexagonal nanotubes exhibit metallic behavior in the case of finite and infinite structures. These theor. results provide useful information for application of spintronics and other nanodevices.
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891Gueorguiev, G. K.; Stafström, S.; Hultman, L. Nano-wire formation by self-assembly of silicon–metal cage-like molecules. Chem. Phys. Lett. 2008, 458, 170– 174, DOI: 10.1016/j.cplett.2008.04.108891https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmsFChsbc%253D&md5=be565c4eb1e6be6763357521f748e441Nanowire formation by self-assembly of silicon-metal cage-like moleculesGueorguiev, G. K.; Stafstroem, S.; Hultman, L.Chemical Physics Letters (2008), 458 (1-3), 170-174CODEN: CHPLBC; ISSN:0009-2614. (Elsevier B.V.)By using DFT calcns. we show that nanowires consisting of endohedral MSi12 cage-like mols. are stable esp. for light transition metal elements (M = Fe, Ni, Co, Ti, V, and Cu). The nanowire assemblies are stabilized by the metal atoms located along their principal axes and can be seen as close Si-based analogs of C nanotubes, but with hexagonal cross-section due to the D6h-symmetry of their MSi12 building blocks. Independently on M, with the increase in the length of a (MSi12)m nanowire, its HOMO-LUMO gap decreases gradually. The metallic behavior of (MSi12)m defines them as possible conductive components for self-assembled nanodevices.
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892Peng, Q.; Shen, J.; Chen, N.-X. Geometry and electronic stability of tungsten encapsulated silicon nanotubes. J. Chem. Phys. 2008, 129, 034704, DOI: 10.1063/1.2949548892https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptVOhsLk%253D&md5=eb19113fbcf136ce27eb7a9a1a03b30dGeometry and electronic stability of tungsten encapsulated silicon nanotubesPeng, Qi; Shen, Jiang; Chen, Nan-XianJournal of Chemical Physics (2008), 129 (3), 034704/1-034704/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)D. functional theory involving generalized gradient approxn. (both PW91 and BLYP level calcns. are considered and compared) correlation functional is used to investigate the stability of W encapsulated Wn@Si6n+6 (n = 1-6) hexagonal prism (HP) nanotubes and Wn@Si8n+4 (n = 1-6) AB2 type nanotubes. We found that the stability of HP type metal encapsulated silicon nanotubes (MESNTs) exhibits odd-even (O-E) oscillation behavior vs. the cluster size which has been proven by the O-E oscillation pattern of the formation energy and the embedded energy. The strong interaction between W and W atoms made W3@Si24 HP type nanotube unstable and we explained why Hiura et al. did not observe clusters bigger than W2@Si18 in their expt. After that, we proposed a new kind of AB2 type MESNT in which the strong interaction between W and W atoms has been eliminated effectively, and it might be connected to form longer nanowire structures. Big distortions appeared for both type structures after reoptimized at BLYP level (the initial structures were chosen as those optimized at PW91 level theory) calcn. Metallic character of these two types of MESNTs has been identified and AB2-MESNTs were found to be more stable than HP type MESNTs by comparing their linearly fitted total binding energy at BLYP level theory. (c) 2008 American Institute of Physics.
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893Singh, A. K.; Kumar, V.; Kawazoe, Y. Metal encapsulated nanotubes of silicon and germanium. J. Mater. Chem. 2004, 14, 555– 563, DOI: 10.1039/b311850a893https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtlWmsbo%253D&md5=d783386d4c65ce3961e15d4869df5d61Metal encapsulated nanotubes of silicon and germaniumSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiJournal of Materials Chemistry (2004), 14 (4), 555-563CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)A review. Nanoforms of silicon such as nanoparticles and nanowires were attracting much attention and recent findings of novel metal encapsulated silicon clusters as well as nanotubes have opened up new avenues for the development of silicon nanostructures. The authors review these recent developments and discuss the findings of the metal encapsulated nanotubes of silicon and germanium using ab initio total energy calcns. These nanotubes are generally found to be metallic. The metalicity is not induced by the doping of metal atoms, though they stabilize silicon and germanium in tubular forms. Transition metal atoms such as Mn and Fe lead to nanotubes that are ferromagnetic making them interesting as nanomagnets. Antiferromagnetic and ferrimagnetic phases also were obtained. A novel aspect of these magnetic nanotubes is the possibility of developing half-metallic nanotubes that could be interesting for nano-spintronics applications. Further possibilities of semiconducting silicon nanotubes are discussed.
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894Singh, A. K.; Briere, T. M.; Kumar, V.; Kawazoe, Y. Magnetism in transition-metal-doped silicon nanotubes. Phys. Rev. Lett. 2003, 91, 146802, DOI: 10.1103/PhysRevLett.91.146802894https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnvVKmur0%253D&md5=1384f099036e5dc952f87e67af910ca1Magnetism in Transition-Metal-Doped Silicon NanotubesSingh, Abhishek Kumar; Briere, Tina M.; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review Letters (2003), 91 (14), 146802/1-146802/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Using first-principles d. functional calcns., we show that hexagonal metallic silicon nanotubes can be stabilized by doping with 3d transition metal atoms. Finite nanotubes doped with Fe and Mn have high local magnetic moments, whereas Co-doped nanotubes have low values and Ni-doped nanotubes are mostly nonmagnetic. The infinite Si24Fe4 nanotube is found to be ferromagnetic with nearly the same local magnetic moment on each Fe atom as in bulk iron. Mn-doped nanotubes are antiferromagnetic, but a ferromagnetic state lies only 0.03 eV higher in energy with a gap in the majority spin bands near the Fermi energy. These materials are interesting for silicon-based spintronic devices and other nanoscale magnetic applications.
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895Dhaka, K.; Bandyopadhyay, D. Magnetism, structures and stabilities of cluster assembled TM@Si nanotubes (TM = Cr, Mn and Fe): A density functional study. Dalton Trans. 2016, 45, 12432– 12443, DOI: 10.1039/C6DT01252C895https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFShsLzE&md5=386b63b5c76468390b24e11d6d387520Magnetism, structures and stabilities of cluster assembled TM@Si nanotubes (TM = Cr, Mn and Fe): a density functional studyDhaka, Kapil; Bandyopadhyay, DebashisDalton Transactions (2016), 45 (31), 12432-12443CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)The present study reports transition metal (TM = Cr, Mn and Fe) doped silicon nanotubes with tunable band structures and magnetic properties by careful selection of cluster assemblies as building blocks using the 1st-principles d. functional theory. The transition metal doping and in addn., the hydrogen termination process can stabilize the pure silicon nanoclusters or cluster assemblies and then it could be extended as magnetic nanotubes with finite magnetic moments. Study of the band structures and d. of states (DOS) of different empty and TM doped nanotubes (Type 1 to Type 4) show that these nanotubes are useful as metals, semiconductors, semi-metals and half-metals. These designer magnetic materials could be useful in spintronics and magnetic devices of nanoscale order.
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896Li, J.; Wang, J.; Zhao, H.-Y.; Liu, Y. Magnetic silicon nanotube: Role of encapsulated europium atoms. J. Phys. Chem. C 2013, 117, 10764– 10769, DOI: 10.1021/jp401090p896https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXms1Oqs7s%253D&md5=e2fc4a29ee0cfd74a354c61a89b0ec36Magnetic Silicon Nanotube: Role of Encapsulated Europium AtomsLi, Jing; Wang, Jing; Zhao, Hui-Yan; Liu, YingJournal of Physical Chemistry C (2013), 117 (20), 10764-10769CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)A europium-encapsulating silicon nanotube, Eu2@Si30, was predicted based on DFT-PW91 calcns. Electronic structure anal. shows that in Si-Si chem. bonding is characterized by sp2-like hybridization induced by the europium atoms; the hybridizations evidently enhances the stability of the silicon nanotube. The nanotube of Eu2@Si30, with D5h symmetry, retains a high spin magnetic moment of 10 μB. On the basis of Eu2Si30 nanotube, a stable magnetic silicon nanotube (SiNT) was obtained, and it is found to be metallic. Similar to the predictions and speculation of Daedalus, the new magnetic SiNT may have potential applications in the fields of spintronics and high-d. magnetic storage.
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897Wang, J.; Liu, Y. Magnetic silicon fullerenes: Experimental exploration and theoretical insight. J. Cluster Sci. 2016, 27, 861– 873, DOI: 10.1007/s10876-015-0959-6897https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFanur%252FE&md5=259fa72ec4aea7ee5f4132502dade8abMagnetic Silicon Fullerenes: Experimental Exploration and Theoretical InsightWang, Jing; Liu, YingJournal of Cluster Science (2016), 27 (3), 861-873CODEN: JCSCEB; ISSN:1040-7278. (Springer)The present article summarizes progress in research on silicon clusters with encapsulated metal atoms, and specifically focuses on the recent identification of magnetic silicon fullerenes. Considering that C20 forms the smallest known fullerene, the Si20 cluster is of particular interest in this context. While the pure hollow Si20 cage is unstable due to the lack of sp2 hybridization, endohedral doping with a range of metal atoms has been considered to be an effective way to stabilize the cage structure. In order to seek out suitable embedded atoms for stabilizing Si20, a broad search has been made across elements with relatively large at. radius. The rare earth elements have been found to be able to stabilize the Si20 cage in the neutral state by forming R@Si20 fullerene cages. Among these atoms, Eu@Si20 has been reported to yield a stable magnetic silicon fullerene. The central europium atom has a large magnetic moment of nearly 7.0 μB. In addn., based on a stable Eu2Si30 tube, a magnetic silicon nanotube has been constructed and discussed. These magnetic silicon fullerenes and nanotubes may have potential applications in the fields of spintronics and high-d. magnetic storage.
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898Sirichantaropass, S.; García-Suárez, V.; Lambert, C. J. Electronic properties of alkali-and alkaline-earth-intercalated silicon nanowires. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 75, 075328, DOI: 10.1103/PhysRevB.75.075328898https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXislarsb0%253D&md5=aa511f53f72c1f2ab194623875606a50Electronic properties of alkali- and alkaline-earth-intercalated silicon nanowiresSirichantaropass, S.; Garcia-Suarez, V. M.; Lambert, C. J.Physical Review B: Condensed Matter and Materials Physics (2007), 75 (7), 075328/1-075328/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We present a first-principles study of the electronic properties of silicon clathrate nanowires intercalated with various types of alkali- or alk.-earth atoms. We find that the band structure of the nanowires can be tailored by varying the impurity atom within the nanowire. The electronic character of the resulting systems can vary from metallic to semiconducting with direct band gaps. These properties make the nanowires specially suitable for elec. and optoelectronic applications.
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899Singh, A. K.; Kumar, V.; Kawazoe, Y. Surface physics, low-dimensional systems, and related topics-Ferromagnetism and piezomagnetic behavior in Mn-doped germanium nanotubes. Phys. Rev. B: Condens. Matter Mater. Phys. 2004, 69, 233406, DOI: 10.1103/PhysRevB.69.233406899https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXls1Wjtr4%253D&md5=9dae3822728dee2e331e910100024be0Ferromagnetism and piezomagnetic behavior in Mn-doped germanium nanotubesSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2004), 69 (23), 233406/1-233406/4CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Using ab initio d. functional calcns., pentagonal and hexagonal nanotubes of Ge can be stabilized in the antiprism structure by doping with Mn atoms. In both cases the infinite nanotubes are metallic and ferromagnetic. Hexagonal nanotubes have the highest av. magnetic moments of 3.06 μB per Mn atom found so far in metal doped nanotubes of semiconductors, while the pentagonal nanotubes show a transition from a ferromagnetic to a ferrimagnetic state upon compression with an abrupt change in the magnetic moments, leading to the possibility of these nanotubes to act as a nano-piezomagnet.
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900Singh, A. K.; Kumar, V.; Kawazoe, Y. Design of a very thin direct-band-gap semiconductor nanotube of germanium with metal encapsulation. Phys. Rev. B: Condens. Matter Mater. Phys. 2005, 71, 075312, DOI: 10.1103/PhysRevB.71.075312900https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXitVKisbc%253D&md5=6c8d8a000a6faae94e4fad5578d7dd09Design of a very thin direct-band-gap semiconductor nanotube of germanium with metal encapsulationSingh, Abhishek Kumar; Kumar, Vijay; Kawazoe, YoshiyukiPhysical Review B: Condensed Matter and Materials Physics (2005), 71 (7), 075312/1-075312/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)Using ab initio total energy calcns. we design a very thin semiconducting nanotube of Ge with a direct band gap by encapsulation of Mo or W. This finding is an outcome of studies of assemblies of Ge18Nb2 clusters into nanotubes. The infinite Nb-doped nanotube is metallic. However, the electronic structure has a significant gap above the Fermi level. When Nb is replaced by a Z+1 element such as Mo or W, it leads to the formation of a semiconducting nanotube. The at. structure of these nanotubes is based on a novel alternate prism and antiprism stacking of hexagonal rings of germanium. Such an arrangement is optimal for Ge18M2 (M = Nb, Mo, and W) clusters that serve as the building blocks of nanotubes. By just changing the M atom in the growth process, we can form metallic, semiconducting, and n or p types of nanotubes, opening new possibilities for nanoscale devices.
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901Singh, A. K.; Kumar, V.; Kawazoe, Y. Metal encapsulated nanotubes of germanium with metal dependent electronic properties. Eur. Phys. J. D 2005, 34, 295– 298, DOI: 10.1140/epjd/e2005-00162-1901https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmtFOqtrk%253D&md5=7b2079fa21c875a9a04e1ac191489db3Metal encapsulated nanotubes of germanium with metal dependent electronic propertiesSingh, A. Kumar; Kumar, V.; Kawazoe, Y.European Physical Journal D: Atomic, Molecular and Optical Physics (2005), 34 (1-3), 295-298CODEN: EPJDF6; ISSN:1434-6060. (EDP Sciences)Using ab initio total energy calcns. we demonstrate that the nanotubes of germanium with at. structure based on an alternate prism and antiprism stacking of hexagonal rings, can be stabilized by metal encapsulation. The V or Nb doped infinite nanotube is metallic. However, Mo doping leads to the formation of a metal encapsulated direct band gap semiconducting nanotube of germanium. These nanotubes with metal dependent electronic properties could prove to be vital for the development of future nanotechnologies.
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902Zhou, J.; Giri, S.; Jena, P. 18-Electron rule inspired Zintl-like ions composed of all transition metals. Phys. Chem. Chem. Phys. 2014, 16, 20241– 20247, DOI: 10.1039/C4CP03141E902https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlCjt73J&md5=96d6c3ee0d0b19a091877c3e9196637318-Electron rule inspired Zintl-like ions composed of all transition metalsZhou, Jian; Giri, Santanab; Jena, PurusottamPhysical Chemistry Chemical Physics (2014), 16 (37), 20241-20247CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Zintl phase compds. constitute a unique class of compds. composed of metal cations and covalently bonded multiply charged cluster anions. Potential applications of these materials in soln. chem. and thermoelec. materials have given rise to renewed interest in the search for new Zintl ions. Up to now these ions have been mostly composed of group 13, 14, and 15 post-transition metal elements and no Zintl ions composed of all transition metal elements are known. Using gradient cor. d. functional theory we show that the 18-electron rule can be applied to design a new class of Zintl-like ions composed of all transition metal atoms. We demonstrate this possibility by using Ti@Au122- and Ni@Au62- di-anions as examples of Zintl-like ions. Predictive capability of our approach is demonstrated by showing that FeH64- in an already synthesized complex metal hydride, Mg2FeH6, is a Zintl-like ion, satisfying the 18-electron rule. We also show that novel Zintl phase compds. can be formed by using all transition metal Zintl-like ions as building blocks. For example, a two-dimensional periodic structure of Na2[Ti@Au12] is semiconducting and nonmagnetic while a one-dimensional periodic structure of Mg[Ti@Au12] is metallic and ferromagnetic. Our results open the door to the design and synthesis of a new class of Zintl-like ions and compds. with potential for applications.
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903Yong, Y.; Cui, H.; Zhou, Q.; Su, X.; Kuang, Y.; Li, X. Ultrathin nanowire based on icosahedral W@Au12 and application as NO gas sensor. J. Phys. Chem. Solids 2019, 127, 68– 75, DOI: 10.1016/j.jpcs.2018.12.008903https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisFaqtr3O&md5=7d60615475e023c70723a9eb65214e62Ultrathin nanowire based on icosahedral W@Au12 and application as NO gas sensorYong, Yongliang; Cui, Hongling; Zhou, Qingxiao; Su, Xiangying; Kuang, Yanmin; Li, XiaohongJournal of Physics and Chemistry of Solids (2019), 127 (), 68-75CODEN: JPCSAW; ISSN:0022-3697. (Elsevier Ltd.)In this study, we used first-principles calcns. to investigate the structural and electronic properties of an ultrathin nanowire formed by assembling icosahedral W@Au12 clusters and its application as a NO gas sensor. An ultrathin nanowire with a diam. of about 5.52 Å was produced via the coalescence of icosahedral W@Au12 clusters. The W@Au12-based nanowire exhibited semiconducting properties with a direct band gap. Frequency anal. and mol. dynamics simulations indicated that the nanowire was particularly stable at T = 300 K. The nanowire chemisorbed a NO mol. with moderate adsorption energy, and the N atom in NO bonding with the Au atom was the most stable bond. Anal. of the Boltzmann distribution and transition state demonstrated that the most stable configuration was particularly likely to form. The electronic properties of the W@Au12-based nanowire were changed dramatically by NO adsorption, with a transition from semiconducting to conducting behavior after NO adsorption. However, the adsorption of CO2, CH4, O2, H2, N2, or H2O mols. had little effect on the conductance of the nanowire. Our results indicated that the W@Au12-based nanowire sensor was highly sensitive and selective. The recovery time for the nanowire-based NO sensor was about 12 s at T = 300 K. Therefore, due to its moderate adsorption energy, significant change in the elec. cond., and very rapid recovery time, we conclude that the W@Au12-based nanowire is a promising gas sensor with high performance at NO detection.
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904Li, X.; Yang, J. Computational design of one-dimensional ferromagnetic semiconductors in transition metal embedded stannaspherene nanowires. Chin. J. Chem. 2019, 37, 1021– 1024, DOI: 10.1002/cjoc.201900166904https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1GjtbbE&md5=da46274a25f619671c42073d94395c63Computational Design of One-Dimensional Ferromagnetic Semiconductors in Transition Metal Embedded Stannaspherene NanowiresLi, Xingxing; Yang, JinlongChinese Journal of Chemistry (2019), 37 (10), 1021-1024CODEN: CJOCEV; ISSN:1001-604X. (Wiley-VCH Verlag GmbH & Co. KGaA)Developing low dimensional semiconductors with moderate band gaps, intrinsic ferromagnetism and large magnetic anisotropy energies (MAEs) is very desirable for high-speed nano-spintronic devices, which, however, still remains a big challenge. Here, via first principles calcns., a potential route to realize such materials is proposed based on a new class of one-dimensional transition metal (TM) embedded stannaspherene (Sn122-) nanowires [TM2(Sn12)]∞ (TM = Ti-Ni). Three semiconductors with robust ferromagnetism are achieved with TM = V, Cr and Fe, which all exhibit direct or quasi-direct band gaps around 1.0 eV, rendering their great potentials for visible light optoelectronic applications. Interestingly, [Cr2(Sn12)]∞ and [Fe2(Sn12)]∞ are both identified as bipolar magnetic semiconductors (BMS) with valence and conduction band edges spin polarized in the opposite directions, which are promising for realizing switch of carriers spin orientation by elec. gating, while [V2(Sn12)]∞ exhibits a half semiconductor (HSC) property with valence and conduction band edges spin polarized in the same direction and can be used for spin-polarized carriers generation. Moreover, sizable MAEs are discovered in these nanowires, which are at least two orders of magnitude larger than those of Fe, Co and Ni bulks and also significantly larger than current ferromagnetic semiconductors.
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905Rudberg, E.; Sałek, P.; Luo, Y. Nonlocal exchange interaction removes half-metallicity in graphene nanoribbons. Nano Lett. 2007, 7, 2211– 2213, DOI: 10.1021/nl070593c905https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntVWkt7Y%253D&md5=9e407fca4f9315208fb74e0e3c74f328Nonlocal Exchange Interaction Removes Half-Metallicity in Graphene NanoribbonsRudberg, Elias; Salek, Pawel; Luo, YiNano Letters (2007), 7 (8), 2211-2213CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Band gap studies of zigzag-edge graphene ribbons are presented. While earlier calcns. at LDA level show that zigzag-edge graphene ribbons become half-metallic when cross-ribbon elec. fields are applied, our calcns. with hybrid d. functional demonstrate that finite graphene ribbons behave as half-semiconductors. The spin-dependent band gap can be changed in a wide range, making possible many applications in spintronics.
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906Saranin, A. A.; Zotov, A. V.; Kotlyar, V. G.; Kasyanova, T. V.; Utas, O. A.; Okado, H.; Katayama, M.; Oura, K. Ordered arrays of Be-encapsulated Si nanotubes on Si (111) surface. Nano Lett. 2004, 4, 1469– 1473, DOI: 10.1021/nl049195p906https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXlvFGitLo%253D&md5=a737dd5f77e7c5d3f149b814cf17529bOrdered Arrays of Be-Encapsulated Si Nanotubes on Si(111) SurfaceSaranin, Alexander A.; Zotov, Andrey V.; Kotlyar, Vasily G.; Kasyanova, Tatiana V.; Utas, Oleg A.; Okado, Hideaki; Katayama, Mitsuhiro; Oura, KenjiroNano Letters (2004), 4 (8), 1469-1473CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Using submonolayer Be deposition onto the Si(111) 7 × 7 surface under ultrahigh vacuum conditions, highly ordered honeycomb-like nanostructure arrays have been obtained. Scanning tunneling microscopy anal. of the nanostructure building blocks has revealed that they have compn., size, and properties similar to those theor. predicted for the short Be-encapsulated Si nanotubes.
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907Stegmaier, S.; Fässler, T. F. Na2. 8Cu5Sn5. 6: A crystalline alloy featuring intermetalloid ∞1{Sn0.6@Cu5@Sn5} double-walled nanorods with pseudo-five-fold symmetry. Angew. Chem. 2012, 124, 2701– 2704, DOI: 10.1002/ange.201107985There is no corresponding record for this reference.
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908Wang, Y.; Saranin, A.; Zotov, A.; Lai, M.; Chang, H. Random and ordered arrays of surface magic clusters. Int. Rev. Phys. Chem. 2008, 27, 317– 360, DOI: 10.1080/01442350801943708908https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXkt12hsL0%253D&md5=7d28b2d5246371b9d49c82fafb00e0bfRandom and ordered arrays of surface magic clustersWang, Y. L.; Saranin, A. A.; Zotov, A. V.; Lai, M. Y.; Chang, H. H.International Reviews in Physical Chemistry (2008), 27 (2), 317-360CODEN: IRPCDL; ISSN:0144-235X. (Taylor & Francis Ltd.)A review. Surface magic clusters (SMCs) are clusters exhibiting enhanced stability at certain sizes on a particular surface. Through the formation of SMCs, it is possible to grow an ensemble of nanostructures on a surface with extremely small or essentially zero size dispersion. Such an ensemble of nanostructures with identical size and at. structure is highly desirable for certain nanotechnologies that rely on the homogeneity in the phys. and chem. properties of the constituent nanostructures. This review summarizes current exptl. observations and understanding of SMCs and discusses the most recent progress in the formation of a two-dimensional lattice of SMCs, whose constituent clusters have not only identical size and structure but also the same local environment due to the translational symmetry of the system.
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909Li, J.-L.; Jia, J.-F.; Liang, X.-J.; Liu, X.; Wang, J.-Z.; Xue, Q.-K.; Li, Z.-Q.; John, S. T.; Zhang, Z.; Zhang, S. Spontaneous assembly of perfectly ordered identical-size nanocluster arrays. Phys. Rev. Lett. 2002, 88, 066101, DOI: 10.1103/PhysRevLett.88.066101909https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xptl2jsw%253D%253D&md5=3b053404a523a51f8c4c0d8c79f7b9f6Spontaneous Assembly of Perfectly Ordered Identical-Size Nanocluster ArraysLi, Jian-Long; Jia, Jin-Feng; Liang, Xue-Jin; Liu, Xi; Wang, Jun-Zhong; Xue, Qi-Kun; Li, Zhi-Qiang; Tse, John S.; Zhang, Zhenyu; Zhang, S. B.Physical Review Letters (2002), 88 (6), 066101/1-066101/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)A method, by which periodic two-dimensional arrays of identical metal clusters of nanometer size and spacing could be spontaneously obtained by taking advantage of surface mediated clustering, is reported. The versatility of the method is demonstrated for a broad range of metals on Si(111)-( 7×7) substrates. In situ scanning tunneling microscopy anal. of In clusters, combined with first-principles total energy calcns., unveils unique initial-stage at. structures of the surface-supported clusters and the vital steps that lead to the success of this method. A strong interaction between the clusters and the surface holds the key to the obsd. cluster sizes.
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910Zhong, X.; Lee, K.; Choi, B.; Meggiolaro, D.; Liu, F.; Nuckolls, C.; Pasupathy, A.; De Angelis, F.; Batail, P.; Roy, X. Superatomic two-dimensional semiconductor. Nano Lett. 2018, 18, 1483– 1488, DOI: 10.1021/acs.nanolett.7b05278910https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhs1yku7c%253D&md5=a93a9b2f4ceb339f74641af92291f513Superatomic two-dimensional semiconductorZhong, Xinjue; Lee, Kihong; Choi, Bonnie; Meggiolaro, Daniele; Liu, Fang; Nuckolls, Colin; Pasupathy, Abhay; De Angelis, Filippo; Batail, Patrick; Roy, Xavier; Zhu, XiaoyangNano Letters (2018), 18 (2), 1483-1488CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Structural complexity is of fundamental interest in materials science because it often results in unique phys. properties and functions. Founded on this idea, the field of solid state chem. has a long history and continues to be highly active, with new compds. discovered daily. By contrast, the area of two-dimensional (2D) materials is young, but its expansion, although rapid, is limited by a severe lack of structural diversity and complexity. Here, we report a novel 2D semiconductor with a hierarchical structure composed of covalently linked Re6Se8 clusters. The material, a 2D structural analog of the Chevrel phase, is prepd. via mech. exfoliation of the van der Waals solid Re6Se8Cl2. Using scanning tunneling spectroscopy, photoluminescence and UPS, and first-principles calcns., we det. the electronic bandgap (1.58 eV), optical bandgap (indirect, 1.48 eV), and exciton binding energy (100 meV) of the material. The latter is consistent with the partially 2D nature of the exciton. Re6Se8Cl2 is the first member of a new family of 2D semiconductors whose structure is built from superat. building blocks instead of simply atoms; such structures will expand the conceptual design space for 2D materials research.
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911Miyazaki, T.; Kanayama, T. Ultrathin layered semiconductor: Si-rich transition metal silicide. Jpn. J. Appl. Phys. 2007, 46, L28– L30, DOI: 10.1143/JJAP.46.L28911https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXht1GgsLY%253D&md5=a5762cabd79bc499e4c0ddc5614a2e96Ultrathin layered semiconductor. Si-rich transition metal silicideMiyazaki, Takehide; Kanayama, ToshihikoJapanese Journal of Applied Physics, Part 2: Letters & Express Letters (2007), 46 (1-3), L28-L30CODEN: JAPLD8 ISSN:. (Japan Society of Applied Physics)By ab initio calcn., we predict an atomically thin, stable layered semiconducting crystal (ZrSi12)n, which may be a prototype candidate material for the thin film channels of ultimately scaled metal-oxide-semiconductor (MOS) transistors. This material is composed of 3 at. layers, in which a layer of Zr atoms is sandwiched by 2 layers of Si atoms. The Si atoms are arranged in graphene-like structures. This material is favorably formed from isolated ZrSi12 clusters. The energy band gap is of the indirect transition type and ∼0.3 eV in a generalized gradient approxn. to the d. functional theory. Both valence-band max. and conduction-band min. wavefunctions can be characterized by a hybrid of Zr d- and Si p-orbitals.
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912Liu, Z.; Wang, X.; Cai, J.; Zhu, H. Room-temperature ordered spin structures in cluster-assembled single V@Si12 sheets. J. Phys. Chem. C 2015, 119, 1517– 1523, DOI: 10.1021/jp508509e912https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFOgtr7K&md5=bfac71b498741a8f9343638781e3d0e9Room-Temperature Ordered Spin Structures in Cluster-Assembled Single V@Si12 SheetsLiu, Zhifeng; Wang, Xinqiang; Cai, Jiangtao; Zhu, HengjiangJournal of Physical Chemistry C (2015), 119 (3), 1517-1523CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Since most of the existing pristine two-dimensional (2D) materials are either intrinsically nonmagnetic or magnetic with small magnetic moment per unit cell and weak strength of magnetic coupling, introducing transition metal atoms in various nanosheets was widely used for achieving a desired 2-dimensional magnetic material. However, the problem of surface clustering for the doped transition metal atoms is still challenging. The authors demonstrate via 1st-principles calcns. that the recently exptl. characterized endohedral Si cage V@Si12 clusters can construct two types of single cluster sheets exhibiting hexagonal porous or honeycomb-like framework with regularly and sep. distributed V atoms. For the ground state of these two sheets, the preferred magnetic coupling is ferromagnetic due to a free-electron-mediated mechanism. By using external strain, the magnetic moments and strength of magnetic coupling for these two sheets can be deliberately tuned, which would be propitious to their advanced applications. More attractively, the authors' 1st-principles mol. dynamics simulations show that both the structure and strength of ferromagnetic coupling for the pristine porous sheet are stable enough to survive at room temp. The insights obtained in this work highlight a new avenue to achieve 2-dimensional Si-based spintronics nanomaterials.
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913Nie, Z.; Guo, P.; Zheng, J.; Zhao, P.; Wan, Y.; Jiang, Z. Electronic and magnetic properties of two dimensional cluster-assembled materials based on TM@Si12 (TM = 3d transition metal) clusters. Comput. Mater. Sci. 2018, 146, 134– 142, DOI: 10.1016/j.commatsci.2018.01.018913https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsF2gtLk%253D&md5=ed06c15cf2441b61c90b63987e6dc549Electronic and magnetic properties of two dimensional cluster-assembled materials based on TM@Si12 (TM = 3d transition metal) clustersNie, Zheng; Guo, Ping; Zheng, Jiming; Zhao, Puju; Wan, Yun; Jiang, ZhenyiComputational Materials Science (2018), 146 (), 134-142CODEN: CMMSEM; ISSN:0927-0256. (Elsevier B.V.)Electronic and magnetic properties of two dimensional (2D) cluster-assembled materials based on TM@Si12 (TM = 3d transition metal) clusters were systematically investigated by using the d. functional method. Taking the hexagonal prism TM @Si12 as a building block, we constructed four different kinds of 2D crystal structures, each with a higher stability than the corresponding individual clusters. The hexagonal honeycomb and porous structures are proved to be thermodynamically stable at room temp. by first-principles mol. dynamics simulations, and the honeycomb structure is more favorable in energy than the porous structure. The magnetic coupling properties of the honeycomb and porous structures based on TM@Si12 were further studied in detail. The results show that almost all of the hexagonal TM@Si12 2D lattice exhibit a certain degree of magnetic ordering. These studies provide insights into the effective design of 2D spintronic materials.
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914Nakaya, M.; Iwasa, T.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Formation of a superatom monolayer using gas-phase-synthesized Ta@Si16 nanocluster ions. Nanoscale 2014, 6, 14702– 14707, DOI: 10.1039/C4NR04211E914https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhslaisrvE&md5=9e29d9327b0b2b610e3b27cbf8293672Formation of a superatom monolayer using gas-phase-synthesized Ta@Si16 nanocluster ionsNakaya, Masato; Iwasa, Takeshi; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiNanoscale (2014), 6 (24), 14702-14707CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The controlled assembly of superat. nanocluster ions synthesized in the gas phase is a key technol. for constructing a novel series of functional nanomaterials. However, it is generally difficult to immobilize them onto a conductive surface while maintaining their original properties owing to undesirable modifications of their geometry and charge state. In this study, it has been shown that this difficulty can be overcome by controlling the donor-acceptor interaction between nanoclusters and surfaces. Cations of Ta-atom-encapsulated Si16 cage nanoclusters (Ta@Si16) behaving as rare-gas-like superatoms are synthesized in the gas phase and deposited on conductive surfaces terminated with acceptor-like C60 and donor-like α-sexithiophene (6T) mols. Scanning tunneling microscopy and spectroscopy have demonstrated that Ta@Si16 cations can be densely immobilized onto C60-terminated surfaces while retaining their cage shape and pos. charge, which is realized by creating binary charge transfer complexes (Ta@Si16+-C60-) on the surfaces. The Ta@Si16 nanoclusters exhibit excellent thermal stability on C60-terminated surfaces similar to those in the gas phase, whereas the nanoclusters destabilize at room temp. on 6T-terminated surfaces owing to the loss of electronic closure via a change in the charge state.
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915Ohta, T.; Shibuta, M.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Charge transfer complexation of Ta-encapsulating Ta@Si16 superatom with C60. J. Phys. Chem. C 2016, 120, 15265– 15271, DOI: 10.1021/acs.jpcc.6b04955915https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFahur7E&md5=2672146545dfb246e45c70a73b02fde1Charge Transfer Complexation of Ta-Encapsulating Ta@Si16 Superatom with C60Ohta, Tsutomu; Shibuta, Masahiro; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiJournal of Physical Chemistry C (2016), 120 (28), 15265-15271CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The tantalum-encapsulating Si16 cage nanocluster superatom (Ta@Si16) has been a promising candidate for a building block of nanocluster-based functional materials. Its chem. states of Ta@Si16 deposited on an electron acceptable C60 fullerene film were evaluated by X-ray and UV photoelectron spectroscopies (XPS and UPS, resp.). XPS results for Si, Ta, and C showed that Ta@Si16 combines with a single C60 mol. to form the superat. charge transfer (CT) complex, (Ta@Si16)+C60-. The high thermal and chem. robustness of the superat. CT complex has been revealed by the XPS and UPS measurements conducted before and after heat treatment and oxygen exposure. Even when heated to 720 K or subjected to ambient oxygen, Ta@Si16 retained its original framework, forming oxides of Ta@Si16 superatom.
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916Nakaya, M.; Iwasa, T.; Tsunoyama, H.; Eguchi, T.; Nakajima, A. Heterodimerization via the covalent bonding of Ta@S16 nanoclusters and C60 molecules. J. Phys. Chem. C 2015, 119, 10962– 10968, DOI: 10.1021/jp511157n916https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXislSnsLs%253D&md5=1785876e0048069af5dc2e9bfa5a382aHeterodimerization via the Covalent Bonding of Ta@Si16 Nanoclusters and C60 MoleculesNakaya, Masato; Iwasa, Takeshi; Tsunoyama, Hironori; Eguchi, Toyoaki; Nakajima, AtsushiJournal of Physical Chemistry C (2015), 119 (20), 10962-10968CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Initial products prepd. via the surface immobilization of Ta-atom-encapsulated Si16 cage (Ta@Si16) nanoclusters on solid surfaces terminated with monolayer films of C60 mols. were investigated using scanning tunneling microscopy (STM). The STM results indicated that marked aggregation and desorption of surface-immobilized Ta@Si16 nanoclusters were not induced, even after thermal annealing at ∼500 K, whereas the local vertical and lateral positions of the Ta@Si16 nanoclusters with respect to neighboring adsorption sites in the C60 film were modified. This local positional transition occurred on C60 monolayer films weakly bonded (via van der Waals forces) to substrates such as highly oriented pyrolytic graphite (HOPG) but did not occur on C60 monolayer films covalently bonded to substrates such as Si(111)7 × 7. These results indicated that the heterodimer consisting of a Ta@Si16 nanocluster and a C60 mol., Ta@Si16-C60, was formed as an initial product via covalent bonding, which inhibited wide-range surface migration of the Ta@Si16 nanoclusters but allowed them to locally change their positions via thermally activated precessional motion. In addn., the transition temp. of the local positional shift was found to decrease as the area d. of the surface-immobilized Ta@Si16 nanoclusters increased, indicating that the barrier height of the precessional motion of the Ta@Si16-C60 heterodimer was decreased due to accumulation of the elastic strain energy generated in the C60 films.
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917Seitsonen, A.; Puska, M. J.; Alatalo, M.; Nieminen, R. M.; Milman, V.; Payne, M. Crystals from metallic clusters: A first-principles calculation. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 48, 1981– 1983, DOI: 10.1103/PhysRevB.48.1981917https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXmtFWhsrY%253D&md5=ee8ad4de3185c803b3caafb53ade7931Crystals from metallic clusters: a first-principles calculationSeitsonen, A. P.; Puska, M. J.; Alatalo, M.; Nieminen, R. M.; Milman, V.; Payne, M. C.Physical Review B: Condensed Matter and Materials Physics (1993), 48 (3), 1981-3CODEN: PRBMDO; ISSN:0163-1829.The interactions of the "magic" Al12Si cluster are studied by first-principles electron-structure calcns. It is shown that clusters arranged into the fcc lattice do not conserve their sepd.-cluster icosahedral structure but coalesce to form a close-packed metal.
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918Liu, F.; Mostoller, M.; Kaplan, T.; Khanna, S.; Jena, P. Evidence for a new class of solids. First-principles study of K(Al13). Chem. Phys. Lett. 1996, 248, 213– 217, DOI: 10.1016/0009-2614(95)01339-3918https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XlvVKgsw%253D%253D&md5=75f3a3cdc4e27d9272f8972fb9c339c5Evidence for a new class of solids. First-principles study of K(Al13)Liu, Feng; Mostoller, Mark; Kaplan, Theodore; Khanna, S. N.; Jena, P.Chemical Physics Letters (1996), 248 (3,4), 213-17CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)The stability of the cryst. phase of a cluster-assembled solid K(Al13) was studied using 1st-principles total energy calcns. K(Al13) may form in the CsCl structure with a lattice const. of 6.52 Å. Unlike the gas phase, in which the ground state of the Al13 cluster is icosahedral, the Al13 becomes cuboctahedral in the solid phase due to crystal field effects. The system is metallic and is stable against lattice distortions. The calcns. suggest that a new metastable solid could be made from two immiscible elements through specially designed synthesis processes.
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919Ashman, C.; Khanna, S.; Liu, F.; Jena, P.; Kaplan, T.; Mostoller, M. (BAl12)Cs: A cluster-assembled solid. Phys. Rev. B: Condens. Matter Mater. Phys. 1997, 55, 15868– 15873, DOI: 10.1103/PhysRevB.55.15868919https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXktVWgu7Y%253D&md5=c10783f31069183f67ea6200abc88b47(BAl12)Cs: a cluster-assembled solidAshman, C.; Khanna, S. N.; Liu, Feng; Jena, P.; Kaplan, T.; Mostoller, M.Physical Review B: Condensed Matter (1997), 55 (23), 15868-15873CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)First-principles calcns. on the geometry and stability of AlnBm clusters have been carried out to examine the effect of size, compn., and electronic-shell filling on their relative stability. It is shown that although Al and B are both trivalent, a BAl12 cluster is more stable than an Al13 by 3.4 eV. The enhanced stability is shown to arise due to the relaxation of surface strain in the Al cage when the central Al is replaced by a smaller B atom. Replacement of an addnl. Al by B to produce B2Al11 results in deformation of the icosahedral BAl12 cage and reduces the stability. The possibility of forming crystals using BAl12 and Cs is examd. via total-energy calcns. It is shown that a solid with icosahedral or cuboctahedral BAl12 and Cs and having the CsCl structure is metastable and could be synthesized.
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920Gong, X. Structure and stability of cluster-assembled solid Al12C(Si): A first-principles study. Phys. Rev. B: Condens. Matter Mater. Phys. 1997, 56, 1091– 1094, DOI: 10.1103/PhysRevB.56.1091920https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXkvVWhsb0%253D&md5=3e15d30ce289d22c64bcb53c7bd07b86Structure and stability of cluster-assembled solid Al12C(Si): a first-principles studyGong, X. G.Physical Review B: Condensed Matter (1997), 56 (3), 1091-1094CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)We have proposed a possible crystal structure for the cluster-assembled solids Al12C(Si), and their electronic structures and stabilities have been studied in the framework of d.-functional theory and ab-initio mol. dynamics. We find that Al12C(Si) clusters are condensed by van der Waals force, with a very small cohesive energy of ∼1.1 eV. The combined steepest descent on ions shows that upon the formation of solid the relaxation of at. distances in the Al12C(Si) clusters is very small. The stability of the Al12C solid is also confirmed by a dynamic simulation at low temp.
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921Zhu, Z.-z.; Tian, B. Electronic properties of solid (Al12B)Li in the CsCl structure. Solid State Commun. 1998, 108, 891– 894, DOI: 10.1016/S0038-1098(98)00400-1There is no corresponding record for this reference.
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922Quan, H.-J.; Gong, X.-G. Electronic structure of cluster-assembled Al12C(Si) solid. Chin. Phys. 2000, 9, 656– 660, DOI: 10.1088/1009-1963/9/9/004There is no corresponding record for this reference.
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923Mondolfo, L. F. Aluminum alloys: structure and properties; Elsevier: Amsterdam, 2013.There is no corresponding record for this reference.
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924Reis, C.; Martins, J.; Pacheco, J. Stability analysis of a bulk material built from silicon cage clusters: A first-principles approach. Phys. Rev. B: Condens. Matter Mater. Phys. 2007, 76, 233406, DOI: 10.1103/PhysRevB.76.233406924https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtVWrtQ%253D%253D&md5=db4dd8f89d1af7dee631068e09b0be61Stability analysis of a bulk material built from silicon cage clusters: A first-principles approachReis, C. L.; Martins, J. L.; Pacheco, J. M.Physical Review B: Condensed Matter and Materials Physics (2007), 76 (23), 233406/1-233406/4CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)We predict a stable bulk material whose constituent units are the exceptionally stable Ti@Si16 clusters. We use first-principles d. functional theory. Our results provide compelling evidence of a stable, wide-band-gap material crystg. in a hcp. structure in which cages bind weakly, similar to fullerite. We further characterize the structural and electronic properties of this material.
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925Reis, C.; Pacheco, J. Bulk materials made of silicon cage clusters doped with Ti, Zr, or Hf. J. Phys.: Condens. Matter 2010, 22, 035501, DOI: 10.1088/0953-8984/22/3/035501925https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkt12hs7o%253D&md5=1c5c17c442092bb1b50375015266d9a9Bulk materials made of silicon cage clusters doped with Ti, Zr, or HfReis, C. L.; Pacheco, J. M.Journal of Physics: Condensed Matter (2010), 22 (3), 035501/1-035501/7CODEN: JCOMEL; ISSN:0953-8984. (Institute of Physics Publishing)We investigate the feasibility of assembling the exceptionally stable isovalent X@Si16 (X = Ti, Zr and Hf) nanoparticles to form new bulk materials using first-principles d. functional theory. Our results predict the formation of stable, wide band-gap materials crystg. in HCP structures in which the cages bind weakly, similar to fullerite. This study suggests new pathways through which endohedral cage clusters may constitute a viable means toward the prodn. of synthetic materials with pre-defined phys. and chem. properties.
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926Gunnarsson, O. Superconductivity in fullerides. Rev. Mod. Phys. 1997, 69, 575– 606, DOI: 10.1103/RevModPhys.69.575926https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXivVaktL0%253D&md5=8bf26b6a4c41944b718964224a9c3778Superconductivity in fulleridesGunnarsson, O.Reviews of Modern Physics (1997), 69 (2), 575-606CODEN: RMPHAT; ISSN:0034-6861. (American Physical Society)Exptl. studies of the superconductive properties of fullerides are briefly reviewed. Theor. calcns. of the electron-phonon coupling, in particular for the intramol. phonons, are discussed extensively. The calcns. are compared with coupling consts. deduced from a no. of different exptl. techniques. It is discussed why A3C60 are not Mott-Hubbard insulators, in spite of the large Coulomb interaction. Ests. of the Coulomb pseudopotential μ*, describing the effect of the Coulomb repulsion on the supercond., as well as possible electronic mechanisms for the supercond., are reviewed. The calcn. of various properties within the Migdal-Eliashberg theory and attempts to go beyond this theory are described.
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927Laurrabaquio, G. L.; Torres, M. B.; Fernández, E. M.; Balbás, L. C. Trends in the formation of aggregates and crystals from M@Si16 clusters: A study from first principle calculations. J. Math. Chem. 2010, 48, 109– 117, DOI: 10.1007/s10910-009-9637-y927https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXnt1alt7k%253D&md5=d84769b24744ab9f86d89df40ad85d4bTrends in the formation of aggregates and crystals from M@Si16 clusters: a study from first principle calculationsLaurrabaquio, Guadalupe Lopez; Torres, M. Begona; Fernandez, Eva. M.; Balbas, L. CarlosJournal of Mathematical Chemistry (2010), 48 (1), 109-117CODEN: JMCHEG; ISSN:0259-9791. (Springer)We have shown recently that the ground state and low-lying energy isomers of the endohedral M@Si16 clusters (M = Sc-, Ti, V+) have a nearly spherical cage-like symmetry with a closed shell electronic structure which conforms them as exceptional stable entities. This is manifested, among other properties, by a large Homo-Lumo gap about 2 eV which suggest the possibility of using these clusters as basic units (superatoms) to construct optoelectronic materials. As a first step in that direction, we have studied in this work, by means of first principles calcns., the trends in the formation of [Ti@Si16]n , [Sc@Si16K]n , and [V@Si16F]n aggregates as their size increases, going from linear to planar to three dimensional arrangements. The most favorable configurations for n ≥ 2 are those formed from the fullerene-like D4d isomer of M@Si16, instead of the ground state Frank-Kasper Td structure of the isolated M@Si16 unit, joined by Si-Si bonds between the Si atoms of the square faces. In all cases the Homo-Lumo gap for the most favorable structure decrease with the size n. Trends for the binding energy, dipole moment, and other electronic properties are also discussed. Several crystal structures constructed from these superatom, supermols., and aggregates have been tested and preliminary results are summarily commented.
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928Pacheco, J.; Gueorguiev, G.; Martins, J. L. First-principles study of the possibility of condensed phases of endohedral silicon cage clusters. Phys. Rev. B: Condens. Matter Mater. Phys. 2002, 66, 033401, DOI: 10.1103/PhysRevB.66.033401928https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmtVGgurs%253D&md5=21fbf65c29ff8326f07a61c7e476d855First-principles study of the possibility of condensed phases of endohedral silicon cage clustersPacheco, J. M.; Gueorguiev, G. K.; Martins, Jose LuisPhysical Review B: Condensed Matter and Materials Physics (2002), 66 (3), 033401/1-033401/3CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)Recently, a new set of clusters in which twelve Si atoms encapsulate one transition metal atom were found to be esp. stable. Making use of MSi12 clusters (M = Nb,W) we carry out a first-principles study of the possibility of synthesizing a cryst. phase using such clusters as elementary building blocks. To this end we carry out an ab initio study of the interaction energy between two MSi12 clusters as a function of their sepn. We also perform an ab initio Langevin quantum mol. dynamics simulation of solid MSi12 at const. temp. and pressure. We find that the interaction energy between Si atoms in neighboring clusters is comparable to that found in bulk Si. In the solid phase, the cage structure of MSi12 disappears during the simulation. The clusters can not conserve their integrity in condensed phases.
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929Uchida, N.; Kintou, H.; Matsushita, Y.; Tada, T.; Kanayama, T. Synthesis of new amorphous semiconductors assembled from transition-metal-encapsulating Si clusters. Appl. Phys. Express 2008, 1, 121502, DOI: 10.1143/APEX.1.121502929https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXns1ejsA%253D%253D&md5=d6ac4871643e0797fcab880538c1f09bSynthesis of new amorphous semiconductors assembled from transition-metal-encapsulating Si clustersUchida, Noriyuki; Kintou, Hiroshi; Matsushita, Yusuke; Tada, Tetsuya; Kanayama, ToshihikoApplied Physics Express (2008), 1 (12), 121502/1-121502/3CODEN: APEPC4; ISSN:1882-0778. (Japan Society of Applied Physics)The authors synthesized amorphous films composed of transition-metal-encapsulating Si clusters (MSin: M = Mo or Nb) by deposition of hydrogenated MSinHx clusters onto SiO2 substrates followed by annealing at 500° for dehydrogenation. The MoSin (n = 7-16) cluster films are semiconductors with an optical gap > 0.6 eV and resistivity > 1 Ω cm. In particular, the MoSi12 cluster film has a large gap of 1.1 eV and resistivity of 120 Ω cm with high hole mobility of 32 cm2/(V s). In these films, Si atoms form amorphous networks similar to those in hydrogenated amorphous Si but the electronic disorder is reduced using MSin clusters as the building blocks.
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930Matxain, J. M.; Piris, M.; Lopez, X.; Ugalde, J. M. Thermally stable solids based on endohedrally doped ZnS clusters. Chem. - Eur. J. 2009, 15, 5138– 5144, DOI: 10.1002/chem.200802472930https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXls12ktro%253D&md5=1a4e0065cdf2e0da124bb1afc47839a1Thermally Stable Solids Based on Endohedrally Doped ZnS ClustersMatxain, Jon M.; Piris, Mario; Lopez, Xabier; Ugalde, Jesus M.Chemistry - A European Journal (2009), 15 (20), 5138-5144CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)The existence of inorg., hollow, fullerene-like ZnS clusters was theor. predicted and then recently confirmed exptl. These clusters trap alkali metals and halogens because the ionization energies (IE) of alkali metals are very similar to the electron affinities (EA) of halogens. This opens the possibility of forming mol. solids composed of these fullerene building blocks because the energy released due to the difference between the IE and EA would be very small. Herein the authors have focused on assembling bare Zn12S12 and endohedral X@Zn12S12-Y@Zn12S12 dimers (X = Na, K; Y = Cl, Br) by considering the square-faces-square orientation of every two adjacent clusters, which leads to a fcc. cubic crystal structure in the solid. The structures were fully optimized in all cases, and their thermal stability was confirmed by ab initio thermal mol. dynamics calcns. The optimum lattice parameter of the solids is ∼13.8 Å, which corresponds to distances of ∼2.5 Å between monomers, which is typical of covalent Zn[bond]S bonds. The resulting solids are nanoporous materials similar to B12N12. Due to their nanoporous structure, these zeolite-shaped solids could be used in heterogeneous catalysis and as storage materials and mol. sieves.
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931Jimenez-Izal, E.; Matxain, J. M.; Piris, M.; Ugalde, J. M. Self-assembling endohedrally doped CdS nanoclusters: New porous solid phases of CdS. Phys. Chem. Chem. Phys. 2012, 14, 9676– 9682, DOI: 10.1039/c2cp41273j931https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XptVWmurg%253D&md5=b7514c1fbd365c69857cd8e734bae32fSelf-assembling endohedrally doped CdS nanoclusters: new porous solid phases of CdSJimenez-Izal, Elisa; Matxain, Jon M.; Piris, Mario; Ugalde, Jesus M.Physical Chemistry Chemical Physics (2012), 14 (27), 9676-9682CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Hollow CdS nanoclusters were predicted to trap alkali metals and halogen atoms inside their cavity. Furthermore, electron affinities (EA) of endohedrally halogen doped clusters and ionization potentials (IE) of endohedrally alkali doped clusters were predicted to be very similar. This makes them suitable to build cluster-assembled materials, in the same vein as do related ZnO, ZnS and MgO nanoclusters, which yield porous solid materials. With this aim in mind, we have focused on the assembly of bare CdiSi and endohedral K@CdiSi-X@CdiSi (i = 12, 16, X = Cl, Br) clusters in order to obtain solids with tailored semiconducting and structural properties. Since these hollow nanoclusters possess square and hexagonal faces, three different orientations have to be considered, namely, edge-to-edge (E-E), square-to-square (S-S) and hexagon-to-hexagon (H-H). These three orientations lead to distinct zeolite-like nanoporous bulk CdS solid phases denoted as SOD, LTA and FAU. These solids are low-d. cryst. nanoporous materials that might be useful in a wide range of applications ranging from mol. sieves for heterogeneous catalysis to gas storage templates.
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932Jadzinsky, P. D.; Calero, G.; Ackerson, C. J.; Bushnell, D. A.; Kornberg, R. D. Structure of a thiol monolayer-protected gold nanoparticle at 1.1 Å resolution. Science 2007, 318, 430– 433, DOI: 10.1126/science.1148624932https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtFOjtb%252FP&md5=8d0b844dcfdef488f021281f40da3a21Structure of a Thiol Monolayer-Protected Gold Nanoparticle at 1.1 Å ResolutionJadzinsky, Pablo D.; Calero, Guillermo; Ackerson, Christopher J.; Bushnell, David A.; Kornberg, Roger D.Science (Washington, DC, United States) (2007), 318 (5849), 430-433CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Structural information on nanometer-sized gold particles has been limited, due in part to the problem of prepg. homogeneous material. Here we report the crystn. and x-ray structure detn. of a p-mercaptobenzoic acid (p-MBA)-protected gold nanoparticle, which comprises 102 gold atoms and 44 p-MBAs. The central gold atoms are packed in a Marks decahedron, surrounded by addnl. layers of gold atoms in unanticipated geometries. The p-MBAs interact not only with the gold but also with one another, forming a rigid surface layer. The particles are chiral, with the two enantiomers alternating in the crystal lattice. The discrete nature of the particle may be explained by the closing of a 58-electron shell.
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933Joshi, C. P.; Bootharaju, M. S.; Alhilaly, M. J.; Bakr, O. M. [Ag25(SR)18]−: The “golden” silver nanoparticle. J. Am. Chem. Soc. 2015, 137, 11578– 11581, DOI: 10.1021/jacs.5b07088933https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVahs7%252FP&md5=0aedccfa13c28566d6b94432617e35cf[Ag25(SR)18]-: The "Golden" Silver NanoparticleJoshi, Chakra P.; Bootharaju, Megalamane S.; Alhilaly, Mohammad J.; Bakr, Osman M.Journal of the American Chemical Society (2015), 137 (36), 11578-11581CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Ag nanoparticles with an atomically precise mol. formula [Ag25(SR)18]- (-SR: thiolate) are synthesized, and their single-crystal structure is detd. This synthesized nanocluster is the only Ag nanoparticle that has a virtually identical analog in Au, i.e., [Au25(SR)18]-, in terms of no. of metal atoms, ligand count, superatom electronic configuration, and at. arrangement. Also, both [Ag25(SR)18]- and its Au analog share a no. of features in their optical absorption spectra. This unprecedented mol. analog in Ag to mimic Au offers the 1st model nanoparticle platform to study the centuries-old problem of understanding the fundamental differences between Ag and Au in terms of nobility, catalytic activity, and optical property.
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934Aikens, C. M. Electronic and geometric structure, optical properties, and excited state behavior in atomically precise thiolate-stabilized noble metal nanoclusters. Acc. Chem. Res. 2018, 51, 3065– 3073, DOI: 10.1021/acs.accounts.8b00364934https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1Smt7fF&md5=76013309796c7828faa5b685259dd813Electronic and Geometric Structure, Optical Properties, and Excited State Behavior in Atomically Precise Thiolate-Stabilized Noble Metal NanoclustersAikens, Christine M.Accounts of Chemical Research (2018), 51 (12), 3065-3073CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)Ligand-protected noble metal nanoclusters are of interest for their potential applications in areas such as bioimaging, catalysis, photocatalysis, and solar energy harvesting. These nanoclusters can be prepd. with at. precision, which means that their stoichiometries can be ascertained; the properties of these nanoclusters can vary significantly depending on the exact stoichiometry and geometric structure of the system. This leads to important questions such as: What are the general principles that underlie the phys. properties of these nanoclusters. Do these principles hold for all systems. What properties can be tuned by varying the size and compn. of the system. In this Account, the authors describe research that was performed to analyze the electronic structure, linear optical absorption, and excited state dynamics of thiolate-stabilized noble metal nanoclusters. The authors focus primarily on two systems, Au25(SR)18- and Au38(SR)24, as models for understanding the principles underlying the electronic structure, optical properties, luminescence, and transient absorption in these systems. In these nanoclusters, the orbitals near the HOMO-LUMO gap primarily arise from at. 6sp orbitals located on Au atoms in the Au core. The resulting nanocluster orbitals are delocalized throughout the core of these systems. Below the core-based orbitals lies a set of orbitals that are primarily composed of Au 5d and S 3p AOs from atoms located around the exterior Au-thiolate oligomer motifs. This set of orbitals has a higher d. of states than the set arising from the core 6sp orbitals. Optical absorption peaks in the near-IR and visible regions of the absorption spectrum arise from excitations between core orbitals (lowest energy peaks) and excitations from oligomer-based orbitals to core-based orbitals (higher energy peaks). Nanoclusters with different stoichiometries have varying gaps between the core orbitals themselves as well as between the band of oligomer-based orbitals and the band of core orbitals. These gaps can slow down nonradiative electron transfer between excited states that have different character; the excited state electron and hole dynamics depend on these gaps. Nanoclusters with different stoichiometries also exhibit different luminescence properties. Depending on factors that may include the symmetry of the system and the rigidity of the core, the nanocluster can undergo large or small nuclear changes upon photoexcitation, which affects the obsd. Stokes shift in these systems. This dependence on stoichiometry and compn. suggests that the size and the corresponding geometry of the nanocluster is an important variable that can be used to tune the properties of interest. How does doping affect these principles. Replacement of Au atoms with Ag atoms changes the energetics of the sp and d AOs that make up the nanocluster orbitals. Ag atoms have higher energy sp orbitals, and the resulting nanocluster orbitals are shifted in energy as well. This affects the HOMO-LUMO gap, the oscillator strength for transitions, the spacings between the different bands of orbitals, and, as a consequence, the Stokes shift and excited state dynamics of these systems. Probably nanocluster doping is one way to control and tune properties for use in potential applications.
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935Song, Y.; Lambright, K.; Zhou, M.; Kirschbaum, K.; Xiang, J.; Xia, A.; Zhu, M.; Jin, R. Large-scale synthesis, crystal structure, and optical properties of the Ag146Br2(SR)80 nanocluster. ACS Nano 2018, 12, 9318– 9325, DOI: 10.1021/acsnano.8b04233935https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsFagtrrL&md5=9148ac63309fc7f15f983991687e361bLarge-Scale Synthesis, Crystal Structure, and Optical Properties of the Ag146Br2(SR)80 NanoclusterSong, Yongbo; Lambright, Kelly; Zhou, Meng; Kirschbaum, Kristin; Xiang, Ji; Xia, Andong; Zhu, Manzhou; Jin, RongchaoACS Nano (2018), 12 (9), 9318-9325CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Solving the at. structure of large-sized metal nanoclusters is a highly challenging task yet critically important for understanding the properties and developing applications. Herein, we report a stable silver nanocluster-Ag146Br2(SR)80 (where SR = 4-isopropylbenzenethiolate)-with its structure solved by X-ray crystallog. Gram-scale synthesis with high yield has been achieved by a one-pot reaction, which offers opportunities for functionalization and applications. This silver nanocluster possesses a core-shell structure with a Ag51 core surrounded by a shell of Ag95Br2S80. The Ag51 core can be viewed as a distorted decahedron, endowing this nanocluster with quantized electronic transitions. In the surface-protecting layer, five different types of S-Ag coordination modes are obsd., ranging from the linear Ag-S-Ag to S-Ag3 (triangle) and S-Ag4 (square). Furthermore, temp.-dependent optical absorption and ultrafast electron dynamics are conducted to explore the relationship between the properties and structure, demonstrating that the distorted metal core and "flying saucer"-like shape of this nanocluster have significant effects on the electronic behavior. A comparison with multiple sizes of Ag nanoclusters also provides some insights into the evolution from mol. to metallic behavior.
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936Jin, S.; Du, W.; Wang, S.; Kang, X.; Chen, M.; Hu, D.; Chen, S.; Zou, X.; Sun, G.; Zhu, M. Thiol-induced synthesis of phosphine-protected gold nanoclusters with atomic precision and controlling the structure by ligand/metal engineering. Inorg. Chem. 2017, 56, 11151– 11159, DOI: 10.1021/acs.inorgchem.7b01458936https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVamsbrK&md5=5588a05ede0b7e24867fc286d6c28dd3Thiol-Induced Synthesis of Phosphine-Protected Gold Nanoclusters with Atomic Precision and Controlling the Structure by Ligand/Metal EngineeringJin, Shan; Du, Wenjun; Wang, Shuxin; Kang, Xi; Chen, Man; Hu, Daqiao; Chen, Shuang; Zou, Xuejuan; Sun, Guodong; Zhu, ManzhouInorganic Chemistry (2017), 56 (18), 11151-11159CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Efficient synthesis of atomically precise phosphine-capped Au nanocluster (with >10 metal atoms) is important to deeply understand the relation between structure and properties. Herein, the authors successfully use the thiol-induced synthesis method and obtain three atomically precise phosphine-protected Au nanoclusters. Single-crystal x-ray structural anal. reveals that the nanoclusters are [Au13(Dppm)6](BPh4)3, [Au18(Dppm)6Br4](BPh4)2, and [Au20(Dppm)6(CN)6] (Dppm is bis(diphenylphosphino)methane), which are further confirmed by electrospray ionization mass spectrometry, TGA, and XPS. Meanwhile, [Au18(Dppm)6Br4](BPh4)2 could be converted into [Au13(Dppm)6](BPh4)3 and [Au20(Dppm)6(CN)6] by engineering the surface ligands under excess PPh3 or moderate NaBH3CN, resp. Also, according to the different binding ability of Ag with halogen, the authors successfully achieved target metal exchange on [Au18(Dppm)6Br4](BPh4)2 with Ag-SAdm (HS-Adm is 1-adamantane mercaptan) complex and obtained [AgxAu18-x(Dppm)6Br4](BPh4)2 (x = 1, 2) alloy nanoclusters. The authors' work will contribute to more intensive understanding on synthesizing phosphine-protected nanoclusters as well as shedding light on the structure-property correlations in the nanocluster range.
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937Chakraborty, I.; Pradeep, T. Atomically precise clusters of noble metals: Emerging link between atoms and nanoparticles. Chem. Rev. 2017, 117, 8208– 8271, DOI: 10.1021/acs.chemrev.6b00769937https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpt1Cnu70%253D&md5=a4715fc394d2a15e47d448929ad223d7Atomically Precise Clusters of Noble Metals: Emerging Link between Atoms and NanoparticlesChakraborty, Indranath; Pradeep, ThalappilChemical Reviews (Washington, DC, United States) (2017), 117 (12), 8208-8271CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. Atomically precise pieces of matter of nanometer dimensions composed of noble metals are new categories of materials with many unusual properties. Over 100 mols. of this kind with formulas such as Au25(SR)18, Au38(SR)24, and Au102(SR)44 as well as Ag25(SR)18, Ag29(S2R)12, and Ag44(SR)30 (often with a few counterions to compensate charges) are known now. They can be made reproducibly with robust synthetic protocols, resulting in colored solns., yielding powders or crystals. They are distinctly different from nanoparticles in their spectroscopic properties such as optical absorption and emission, showing well-defined features, just like mols. They show isotopically resolved mol. ion peaks in mass spectra and provide diverse information when examd. through multiple instrumental methods. Most important of these properties is luminescence, often in the visible-near-IR window, useful in biol. applications. Luminescence in the visible region, esp. by clusters protected with proteins, with a large Stokes shift, has been used for various sensing applications, down to a few tens of mols./ions, in air and water. Catalytic properties of clusters, esp. oxidn. of org. substrates, have been examd. Materials science of these systems presents numerous possibilities and is fast evolving. Computational insights have given reasons for their stability and unusual properties. The mol. nature of these materials is unequivocally manifested in a few recent studies such as intercluster reactions forming precise clusters. These systems manifest properties of the core, of the ligand shell, as well as that of the integrated system. They are better described as protected mols. or aspicules, where aspis means shield and cules refers to mols., implying that they are "shielded mols.". In order to understand their diverse properties, a nomenclature has been introduced with which it is possible to draw their structures with positional labels on paper, with some training. Research in this area is captured here, based on the publications available up to Dec. 2016.
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938Jin, R.; Zeng, C.; Zhou, M.; Chen, Y. Atomically precise colloidal metal nanoclusters and nanoparticles: Fundamentals and opportunities. Chem. Rev. 2016, 116, 10346– 10413, DOI: 10.1021/acs.chemrev.5b00703938https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVeksLnJ&md5=aa1208c72c4e8de1be9a4a906a9bc6c9Atomically Precise Colloidal Metal Nanoclusters and Nanoparticles: Fundamentals and OpportunitiesJin, Rongchao; Zeng, Chenjie; Zhou, Meng; Chen, YuxiangChemical Reviews (Washington, DC, United States) (2016), 116 (18), 10346-10413CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. Colloidal nanoparticles are being intensely pursued in current nanoscience research. Nanochemists are often frustrated by the known fact that no two nanoparticles are the same, which precludes the deep understanding of many fundamental properties of colloidal nanoparticles in which the total structures (core plus surface) must be known. Therefore, controlling nanoparticles with at. precision and solving their total structures have long been major dreams for nanochemists. Recently, these goals are partially fulfilled in the case of gold nanoparticles, at least in the ultrasmall size regime (1-3 nm in diam., often called nanoclusters). This review summarizes the major progress in the field, including the principles that permit atomically precise synthesis, new types of at. structures, and unique phys. and chem. properties of atomically precise nanoparticles, as well as exciting opportunities for nanochemists to understand very fundamental science of colloidal nanoparticles (such as the stability, metal-ligand interfacial bonding, ligand assembly on particle surfaces, aesthetic structural patterns, periodicities, and emergence of the metallic state) and to develop a range of potential applications such as in catalysis, biomedicine, sensing, imaging, optics, and energy conversion. Although most of the research activity currently focuses on thiolate-protected gold nanoclusters, important progress also was achieved in other ligand-protected gold, silver, and bimetal (or alloy) nanoclusters. All of these types of unique nanoparticles will bring unprecedented opportunities, not only in understanding the fundamental questions of nanoparticles but also in opening up new horizons for scientific studies of nanoparticles.
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939Kang, X.; Zhu, M. Tailoring the photoluminescence of atomically precise nanoclusters. Chem. Soc. Rev. 2019, 48, 2422– 2457, DOI: 10.1039/C8CS00800K939https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkt1Wqt7k%253D&md5=a25d2e3afdc1a6d81551c0edc0d36b02Tailoring the photoluminescence of atomically precise nanoclustersKang, Xi; Zhu, ManzhouChemical Society Reviews (2019), 48 (8), 2422-2457CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Due to their atomically precise structures and intriguing chem./phys. properties, metal nanoclusters are an emerging class of modular nanomaterials. Photo-luminescence (PL) is one of their most fascinating properties, due to the plethora of promising PL-based applications, such as chem. sensing, bio-imaging, cell labeling, phototherapy, drug delivery, and so on. However, the PL of most current nanoclusters is still unsatisfactory-the PL quantum yield (QY) is relatively low (generally lower than 20%), the emission lifetimes are generally in the nanosecond range, and the emitted color is always red (emission wavelengths of above 630 nm). To address these shortcomings, several strategies have been adopted, and are reviewed herein: capped-ligand engineering, metallic kernel alloying, aggregation-induced emission, self-assembly of nanocluster building blocks into cluster-based networks, and adjustments on external environment factors. We further review promising applications of these fluorescent nanoclusters, with particular focus on their potential to impact the fields of chem. sensing, bio-imaging, and bio-labeling. Finally, scope for improvements and future perspectives of these novel nanomaterials are highlighted as well. Our intended audience is the broader scientific community interested in the fluorescence of metal nanoclusters, and our review hopefully opens up new horizons for these scientists to manipulate PL properties of nanoclusters. This review is based on publications available up to Dec. 2018.
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940Li, Y.-L.; Wang, Z.-Y.; Ma, X.-H.; Luo, P.; Du, C.-X.; Zang, S.-Q. Distinct photophysical properties in atom-precise silver and copper nanocluster analogues. Nanoscale 2019, 11, 5151– 5157, DOI: 10.1039/C9NR01058K940https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXktVCmurs%253D&md5=62b8c55baa888c0073a3fb1063e6563eDistinct photophysical properties in atom-precise silver and copper nanocluster analoguesLi, Yan-Ling; Wang, Zhao-Yang; Ma, Xiao-Hong; Luo, Peng; Du, Chen-Xia; Zang, Shuang-QuanNanoscale (2019), 11 (12), 5151-5157CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The synthesis of atom-precise analogs of homometallic nanoclusters remains a great challenge. Herein we report the first pair of atom-precise copper/silver-thiolate halide cluster analogs, namely [Cu17/Ag17I3S(C2B10H10S2)6(CH3CN)11] (Cu17 and Ag17), obtained by bottom-up self-assembly and complete-metal-exchange-induced cluster-to-cluster transformation, resp. The differences in optical absorption and emission of these analogs were fully elucidated by exptl. and theor. methods.
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941Nasaruddin, R. R.; Chen, T.; Yan, N.; Xie, J. Roles of thiolate ligands in the synthesis, properties and catalytic application of gold nanoclusters. Coord. Chem. Rev. 2018, 368, 60– 79, DOI: 10.1016/j.ccr.2018.04.016941https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXosFGrt7w%253D&md5=b762e9867a2f611d44d8d0c0212bc2fcRoles of thiolate ligands in the synthesis, properties and catalytic application of gold nanoclustersNasaruddin, Ricca Rahman; Chen, Tiankai; Yan, Ning; Xie, JianpingCoordination Chemistry Reviews (2018), 368 (), 60-79CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)Ultrasmall (<2 nm) ligand-protected metal nanoclusters (NCs) have been an emerging class of functional materials with rich coordination chem., finding increasing acceptance in both basic and applied research owing to their at. precision, well-defined mol. structure, and intriguing mol.-like properties. The presence of ligands on metal NCs is crucial not only for maintaining their at. precision and well-defined structure, but also for their rich coordination chem. with noble metals, influencing the synthesis, and physicochem. and catalytic properties of metal NCs. In this review, we discuss the important roles of ligands to metal NCs, taking water-sol. gold nanoclusters (Au NCs) as an example. The review covers the fundamental understandings (and advances) on the roles of ligands to water-sol. Au NCs in the synthesis (e.g., influencing the size and formation rate, and revealing the growth mechanisms), physicochem. properties (e.g., geometrical structure, chirality, stability, soly., and electronic, photoluminescence and biol. properties) and catalytic applications (e.g., accessibility, activity, selectivity, and coordination of catalytic mechanism of quasi-homogeneous catalysts and immobilization of heterogeneous catalysts). The review also highlights some challenging issues on how ligands and ligand engineering could expand the scope of metal NCs in the synthesis, physicochem. properties, and catalytic application.
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942Liu, X.; Astruc, D. Atomically precise copper nanoclusters and their applications. Coord. Chem. Rev. 2018, 359, 112– 126, DOI: 10.1016/j.ccr.2018.01.001942https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXht1Sjtrk%253D&md5=62152b449191eff83164aa40dca783c6Atomically precise copper nanoclusters and their applicationsLiu, Xiang; Astruc, DidierCoordination Chemistry Reviews (2018), 359 (), 112-126CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)A review. Although Cu nanoparticles (CuNPs) have been subjected to broad investigations, esp. viewing their easy access, low cost and rich catalytic properties, atomically precise copper nanoclusters (CuNCs) are less often examd. due to the difficulties of their isolation in pure form. Yet their study is essential for a better understanding of the mol., phys. and catalytic properties of CuNPs that are in fact mixts. of CuNCs. The review highlights the background and recent progress in CuNCs including the structural and physico-chem. properties and new applications to galvanic reactions, fluorescence and catalysis. Particular emphasis is placed on catalysis for which hydrogen evolution reaction, redn. of CO2 and recent comparative results from our group concerning 1,3-dipolar cycloaddn. of org. azides and alkynes (CuAAC, "click reaction") are detailed. In this latter sub-field the key role of the relative stabilities of the CuNCs on their performances is emphasized as shown with Clayborne and Chen's nanocluster anion [Cu6(SR)6]- [Na+, solvent], R=C7H4NO, solvent=acetone or THF, that shows excellent efficiency for the CuAAC reaction.
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943Fang, J.; Zhang, B.; Yao, Q.; Yang, Y.; Xie, J.; Yan, N. Recent advances in the synthesis and catalytic applications of ligand-protected, atomically precise metal nanoclusters. Coord. Chem. Rev. 2016, 322, 1– 29, DOI: 10.1016/j.ccr.2016.05.003943https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XotlCkurk%253D&md5=efeaba33202118deaed818837d25a0b1Recent advances in the synthesis and catalytic applications of ligand-protected, atomically precise metal nanoclustersFang, Jun; Zhang, Bin; Yao, Qiaofeng; Yang, Yang; Xie, Jianping; Yan, NingCoordination Chemistry Reviews (2016), 322 (), 1-29CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)A review. Due to their excellent catalytic properties under mild reaction conditions, well-defined, nanosized noble metal catalysts have potential applications in the manuf. of fine chems., pharmaceuticals, and food additives. Ligand stabilized MnLm NCs (M: noble metal; n: no. of metal atoms, n < 150; L: ligand; m: no. of ligands) have a long history in catalysis, but recent advances in synthetic strategies and instrumental characterization have led to a renaissance in the catalytic applications of MnLm NCs. Thus, NCs can serve as model catalysts for understanding fundamental aspects of catalysis, but they also exhibit interesting properties in practical applications. MnLm NCs such as the recently investigated thiolated capped Au NCs have unique geometric structures with ultra-small size and strong quantum confinement, both of which are lacking in larger noble metal nanoparticles (>2 nm). The correlations among the catalytic performance of MnLm NCs with the size, structure, and compn. of individual NCs at the at. level can be demonstrated in realistic ambient reaction conditions, thereby contributing to the rational design of highly active catalysts with novel properties. Our current understanding of these newly emerging catalytic NCs is still in its infancy, but some studies have shown their potential for promoting new types of reactions. This review summarizes recent exciting advances in this field (since 2010), esp. the catalytic properties of noble metal NCs in the presence of the ligand shell and after removing the ligand.
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944Kang, X.; Chong, H.; Zhu, M. Au25(SR)18: The captain of the great nanocluster ship. Nanoscale 2018, 10, 10758– 10834, DOI: 10.1039/C8NR02973C944https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXpvVChtbg%253D&md5=bb905f0c5cc71c68584323669ca7a4cdAu25(SR)18: the captain of the great nanocluster shipKang, Xi; Chong, Hanbao; Zhu, ManzhouNanoscale (2018), 10 (23), 10758-10834CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Noble metal nanoclusters are in the intermediate state between discrete atoms and plasmonic nanoparticles and are of significance due to their atomically accurate structures, intriguing properties, and great potential for applications in various fields. In addn., the size-dependent properties of nanoclusters construct a platform for thoroughly researching the structure (compn.)-property correlations, which is favorable for obtaining novel nanomaterials with enhanced physicochem. properties. Thus far, more than 100 species of nanoclusters (mono-metallic Au or Ag nanoclusters, and bi- or tri-metallic alloy nanoclusters) with crystal structures have been reported. Among these nanoclusters, Au25(SR)18-the brightest mol. star in the nanocluster field-is capable of revealing the past developments and prospecting the future of the nanoclusters. Since being successfully synthesized (in 1998, with a 20-yr history) and structurally detd. (in 2008, with a 10-yr history), Au25(SR)18 has stimulated the interest of chemists as well as material scientists, due to the early discovery, easy prepn., high stability, and easy functionalization and application of this mol. star. In this review, the prepn. methods, crystal structures, physicochem. properties, and practical applications of Au25(SR)18 are summarized. The properties of Au25(SR)18 range from optics and chirality to magnetism and electrochem., and the property-oriented applications include catalysis, chem. imaging, sensing, biol. labeling, biomedicine and beyond. Furthermore, the research progress on the Ag-based M25(SR)18 counterpart (i.e., Ag25(SR)18) is included in this review due to its homologous compn., construction and optical absorption to its gold-counterpart Au25(SR)18. Moreover, the alloying methods, metal-exchange sites and property alternations based on the templated Au25(SR)18 are highlighted. Finally, some perspectives and challenges for the future research of the Au25(SR)18 nanocluster are proposed (also holding true for all members in the nanocluster field). This review is directed toward the broader scientific community interested in the metal nanocluster field, and hopefully opens up new horizons for scientists studying nanomaterials. This review is based on the publications available up to March 2018.
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945Yang, J.; Jin, R. New advances in atomically precise silver nanoclusters. ACS Mater. Lett. 2019, 1, 482– 489, DOI: 10.1021/acsmaterialslett.9b00246945https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhslWnurfJ&md5=fc5e6fcd73a15a1764206a2c126e7774New Advances in Atomically Precise Silver NanoclustersYang, Jie; Jin, RongchaoACS Materials Letters (2019), 1 (4), 482-489CODEN: AMLCEF; ISSN:2639-4979. (American Chemical Society)A review. Atomically precise noble metal nanoclusters are ultrasmall particles that are typically composed of tens to hundreds of metal atoms in the core (equiv. sizes 1-3 nm). This new class of nanomaterials is unique in that they are atomically precise and possess uniform structures, high stability, and attractive properties. Built on the significant success of Au nanoclusters, Ag nanoclusters have recently received increasing attention. The majority of reported silver nanocluster sizes exhibit mol.-like properties, whereas larger ones exhibit plasmons characteristic of metallic state (as opposed to mol. state in smaller sizes). Both mol. (i.e., nonmetallic) and metallic nanoclusters hold promise in a wide range of applications. To deepen the understanding of their phys. and chem. properties, precise control over size and detn. of the crystal structure are the top priorities. In recent developments, dozens of silver nanoclusters with definite formulas have been prepd. through various strategies, albeit the structural detn. still lags behind. In this short Review, we summarize the recent progress in ligand-protected silver nanoclusters, including the size-focusing synthetic methods, new sizes, structures, and properties.
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946Christensen, S. L.; MacDonald, M. A.; Chatt, A.; Zhang, P.; Qian, H.; Jin, R. Dopant location, local structure, and electronic properties of Au24Pt(SR)18 nanoclusters. J. Phys. Chem. C 2012, 116, 26932– 26937, DOI: 10.1021/jp310183x946https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslOls7jL&md5=235d33f67b95ebaa7d898195fb076b70Dopant Location, Local Structure, and Electronic Properties of Au24Pt(SR)18 NanoclustersChristensen, Stephen L.; MacDonald, Mark A.; Chatt, Amares; Zhang, Peng; Qian, Huifeng; Jin, RongchaoJournal of Physical Chemistry C (2012), 116 (51), 26932-26937CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We report element-specific X-ray spectroscopy results on the structure and bonding of Au24Pt, a thiolate-protected bimetallic nanocluster. Platinum L3-edge extended X-ray absorption fine-structure (EXAFS) data, in assocn. with XPS compositional anal., was used to identify the location of the Pt dopant to be in the center of the icosahedron Au13 core. Comparison of Au24Pt with the structure of Au25 by gold L3-edge EXAFS clearly shows contraction of both metal-thiolate and metal-metal bond distances, caused by Pt doping. The doping effect on the electronic properties of Au24Pt was further evaluated by high-resoln. Au 4f core-level XPS and ab initio calcns., which elucidate the importance of bimetallic (Pt-Au) bonding and bond contraction effects on the properties of Pt-doped thiolate-gold nanoclusters.
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947Faraday, M. X. The Bakerian Lecture.—Experimental relations of gold (and other metals) to light. Philos. Trans. 1857, 145– 181There is no corresponding record for this reference.
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948Heaven, M. W.; Dass, A.; White, P. S.; Holt, K. M.; Murray, R. W. Crystal structure of the gold nanoparticle [N(C8H17)4][Au25(SCH2CH2Ph)18]. J. Am. Chem. Soc. 2008, 130, 3754– 3755, DOI: 10.1021/ja800561b948https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXivVSktLY%253D&md5=0240b5da3df098e66d93a8ed812a84feCrystal Structure of the Gold Nanoparticle [N(C8H17)4][Au25(SCH2CH2Ph)18]Heaven, Michael W.; Dass, Amala; White, Peter S.; Holt, Kennedy M.; Murray, Royce W.Journal of the American Chemical Society (2008), 130 (12), 3754-3755CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors report the crystal structure of the thiolate Au nanoparticle [TOA+][Au25(SCH2CH2Ph)18-], where TOA+ = N(C8H17)4+. Crystallog. data are given. The crystal structure reveals three types of Au atoms: (a) one central Au atom whose coordination no. is 12 (12 bonds to Au atoms); (b) 12 Au atoms that form the vertexes of an icosahedron around the central atom, whose coordination no. is 6 (five bonds to Au atoms and one to a S atom), and (c) 12 Au atoms that are stellated on 12 of the 20 faces of the Au13 icosahedron. The arrangement of the latter Au atoms may be influenced by aurophilic bonding. Together they form six orthogonal semirings, or staples, of -Au2(SCH2CH2Ph)3- in an octahedral arrangement around the Au13 core.
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949Liu, Z.; Zhu, M.; Meng, X.; Xu, G.; Jin, R. Electron transfer between [Au25(SC2H4Ph)18]− TOA+ and oxoammonium cations. J. Phys. Chem. Lett. 2011, 2, 2104– 2109, DOI: 10.1021/jz200925h949https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpvFCju74%253D&md5=2af37eba2812633b5a362ac5e7ce5c7dElectron Transfer between [Au25(SC2H4Ph)18]-TOA+ and Oxoammonium CationsLiu, Zhao; Zhu, Manzhou; Meng, Xiangming; Xu, Guoyong; Jin, RongchaoJournal of Physical Chemistry Letters (2011), 2 (17), 2104-2109CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)We report intermol. electron transfer between 2,2,6,6-tetramethylpiperidin-1-oxoammonium tetrafluoroborate (TEMPO+BF4-) and thiol-stabilized [Au25(SC2H4Ph)18]-TOA+ (abbreviated as Au25-) nanoclusters. The TEMPO+ cations are generated by single electron oxidn. of piperidine aminoxyl radical TEMPO (2,2,6,6-tetramethylpiperidinyl-oxy). Cyclic voltammetry (CV) and ESR explicitly indicate that two consecutive single-electron transfer reactions occur between TEMPO+ cations and Au25- nanoclusters. NMR (1H NMR) anal. demonstrates that the methylene proton resonances of the thiolate ligands can also be used to monitor the redox process. UV-vis spectroscopic anal. reveals the changes in the absorption peaks of Au25 nanoclusters upon consecutive single-electron transfers between the nanoclusters and TEMPO+ cations. The ease of control over the redox process involving TEMPO+ allows the prepn. of pure Au25(SC2H4Ph)18+ nanoclusters. The interesting electron-donating properties of Au25(SR)18 clusters may find some promising applications in future studies.
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950Walter, M.; Akola, J.; Lopez-Acevedo, O.; Jadzinsky, P. D.; Calero, G.; Ackerson, C. J.; Whetten, R. L.; Grönbeck, H.; Häkkinen, H. A unified view of ligand-protected gold clusters as superatom complexes. Proc. Natl. Acad. Sci. U. S. A. 2008, 105, 9157– 9162, DOI: 10.1073/pnas.0801001105950https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXosFaksLY%253D&md5=16b25c17a60dc8916f92cc01c71d505dA unified view of ligand-protected gold clusters as superatom complexesWalter, Michael; Akola, Jaakko; Lopez-Acevedo, Olga; Jadzinsky, Pablo D.; Calero, Guillermo; Ackerson, Christopher J.; Whetten, Robert L.; Gronbeck, Henrik; Hakkinen, HannuProceedings of the National Academy of Sciences of the United States of America (2008), 105 (27), 9157-9162CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chem. of nanomaterials. Factors driving the thermodn. stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles protected by thiolate (SR) or phosphine and halide (PR3, X) ligands. The picture has emerged from anal. of large-scale d. functional theory calcns. of structurally characterized compds., namely Au102(SR)44, Au39(PR3)14X6-, Au11(PR3)7X3, and Au13(PR3)10X23+, where X is either a halogen or a thiolate. Attributable to a compact, sym. core and complete steric protection, each compd. has a filled spherical electronic shell and a major energy gap to unoccupied states. Consequently, the exceptional stability is best described by a "noble-gas superatom" analogy. The explanatory power of this concept is shown by its application to many monomeric and oligomeric compds. of precisely known compn. and structure, and its predictive power is indicated through suggestions offered for a series of anomalously stable cluster compns. which are still awaiting a precise structure detn.
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951Grönbeck, H. Correspondence: On the bonding in ligand-protected gold clusters. Nat. Commun. 2017, 8, 1612, DOI: 10.1038/s41467-017-01292-y951https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M3hs1Khtg%253D%253D&md5=01512e82bed86f7214c92f0e4296f3a6Correspondence: On the bonding in ligand-protected gold clustersGronbeck HenrikNature communications (2017), 8 (1), 1612 ISSN:.There is no expanded citation for this reference.
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952Zeng, C.; Qian, H.; Li, T.; Li, G.; Rosi, N. L.; Yoon, B.; Barnett, R. N.; Whetten, R. L.; Landman, U.; Jin, R. Total structure and electronic properties of the gold nanocrystal Au36(SR)24. Angew. Chem., Int. Ed. 2012, 51, 13114– 13118, DOI: 10.1002/anie.201207098952https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1OgtrfE&md5=4b4410495294e447b83023c22eb302d4Total Structure and Electronic Properties of the Gold Nanocrystal Au36(SR)24Zeng, Chenjie; Qian, Huifeng; Li, Tao; Li, Gao; Rosi, Nathaniel L.; Yoon, Bokwon; Barnett, Robert N.; Whetten, Robert L.; Landman, Uzi; Jin, RongchaoAngewandte Chemie, International Edition (2012), 51 (52), 13114-13118CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors report the discovery of an fcc.-type core structure in Au36(SR)24, where SR refers to 4-tert-butylbenzenethiolate. The emergence of an fcc. structure in Au36(SR)24 is surprising, given the small size of the cluster. The total structure was detd. and theor. insights into its bonding and electronic structure are given. The structures and stability of nanoclusters are detd. by a balance between maximization of the metal (gold) cohesive energy and the electronic effect of the conjugated thiolate. A large (approx. 1.7 eV) HOMO-LUMO energy gap confers extreme stability, and originates from the (superatom) shell-structure organization of the electronic energy levels of the cluster.
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953Jin, R.; Nobusada, K. Doping and alloying in atomically precise gold nanoparticles. Nano Res. 2014, 7, 285– 300, DOI: 10.1007/s12274-014-0403-5953https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXht12jsL8%253D&md5=4d9870aa12729870427d0a9aa592f239Doping and alloying in atomically precise gold nanoparticlesJin, Rongchao; Nobusada, KatsuyukiNano Research (2014), 7 (3), 285-300CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)A review. The recent success in the synthesis and total structure detn. of atomically precise gold nanoparticles has provided exciting opportunities for fundamental studies as well as the development of new applications. These unique nanoparticles are of mol. purity and possess well defined formulas (i.e., specific nos. of metal atoms and ligands), resembling org. compds. Crystn. of such molecularly pure nanoparticles into macroscopic single crystals allows for the detn. of total structures of nanoparticles (i.e., the arrangement of metal core atoms and surface ligands) by X-ray crystallog. In this perspective article, we summarize recent efforts in doping and alloying gold nanoparticles with other metals, including Pd, Pt, Ag and Cu. With atomically precise gold nanoparticles, a specific no. of foreign atoms (e.g., Pd, Pt) can be incorporated into the gold core, whereas a range of Ag and Cu substitutions is obsd. but, interestingly, the total no. of metal atoms in the homogold nanoparticle is preserved. The heteroatom substitution of gold nanoparticles allows one to probe the optical, structural, and electronic properties truly at the single-atom level, and thus provides a wealth of information for understanding the intriguing properties of this new class of nanomaterials. [Figure not available: see fulltext.].
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954Negishi, Y.; Munakata, K.; Ohgake, W.; Nobusada, K. Effect of copper doping on electronic structure, geometric structure, and stability of thiolate-protected Au25 nanoclusters. J. Phys. Chem. Lett. 2012, 3, 2209– 2214, DOI: 10.1021/jz300892w954https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFWhs7fM&md5=bf1bb140218d9f99b90cca66a513fae0Effect of Copper Doping on Electronic Structure, Geometric Structure, and Stability of Thiolate-Protected Au25 NanoclustersNegishi, Yuichi; Munakata, Kenta; Ohgake, Wataru; Nobusada, KatsuyukiJournal of Physical Chemistry Letters (2012), 3 (16), 2209-2214CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Several recent studies have attempted to impart [Au25(SR)18]- with new properties by doping with foreign atoms. The effect of Cu doping on the electronic and geometric structures and stability of [Au25(SR)18]- were studied, with the aim of studying the effect of foreign atom doping of [Au25(SR)18]-. CunAu25-n(SC2H4Ph)18 (n = 1-5) was synthesized by reducing complexes formed by the reaction between metal salts (Cu and Au salts) and PhC2H4SH with NaBH4. Mass anal. revealed that the products contained CunAu25-n(SC2H4Ph)18 (n = 1-5) in high purity. Exptl. and theor. anal. of the synthesized clusters revealed that Cu doping alters the optical properties and redox potentials of the cluster, greatly distorts its geometric structure, and reduces the cluster stability in soln. These findings are expected to be useful for developing design guidelines for functionalizing [Au25(SR)18]- through doping with foreign atoms.
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955Negishi, Y.; Iwai, T.; Ide, M. Continuous modulation of electronic structure of stable thiolate-protected Au25 cluster by Ag doping. Chem. Commun. 2010, 46, 4713– 4715, DOI: 10.1039/c0cc01021a955https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXnslSntbw%253D&md5=ccdf3f8b6934c858fd2e7e911e3c4db1Continuous modulation of electronic structure of stable thiolate-protected Au25 cluster by Ag dopingNegishi, Yuichi; Iwai, Takeyuki; Ide, MaoChemical Communications (Cambridge, United Kingdom) (2010), 46 (26), 4713-4715CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)The effect of Ag doping on the electronic structure of a stable thiolate-protected Au25 cluster (Au25(SR)18) was studied by measuring the optical spectra of Au25-nAgn(SC12H25)18 (n = 0-11) and the electronic structure of Au25(SC12H25)18 is sensitive to Ag doping and is continuously modulated by incorporation of Ag atoms.
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956Ghosh, A.; Mohammed, O. F.; Bakr, O. M. Atomic-Level Doping of Metal Clusters. Acc. Chem. Res. 2018, 51, 3094– 3103, DOI: 10.1021/acs.accounts.8b00412956https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1Wlu7bO&md5=7257881c9d3a9f062a629f3c6b679228Atomic-Level Doping of Metal ClustersGhosh, Atanu; Mohammed, Omar F.; Bakr, Osman M.Accounts of Chemical Research (2018), 51 (12), 3094-3103CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)Atomically precise noble metal (mainly silver and gold) nanoclusters are an emerging category of promising functional materials for future applications in energy, sensing, catalysis, and nanoelectronics. These nanoclusters are protected by ligands such as thiols, phosphines, and hydride and have sizes between those of atoms and plasmonic nanoparticles. In metallurgy, the properties of a pure metal are modified by the addn. of other metals, which often offers augmented characteristics, making them more utilizable for real-life applications. In this Account, we discuss how the incorporation of various metal atoms into existing protected nanoclusters tunes their structure and properties.The process of incorporating metals into an existing cluster is known as doping; the product is known as a doped cluster, and the incorporated metal atom is called a dopant/foreign atom. We first present a brief historical overview of protected clusters and the need for doping and explain (with examples) the difference between an "alloy" and a "doped" cluster, which are two frequently confused terms. We then discuss several commonly obsd. challenges in the synthesis of doped clusters: (i) doping produces a mixt. of compns. that prevents the growth of single crystals; (ii) doping with foreign atoms sometimes changes the overall compn. and structure of the parent cluster; and (iii) doping beyond a certain no. of foreign atoms decomps. the doped cluster. After delineating the challenges, we review a few potential synthetic methods for doped clusters: (i) the co-redn. method, (ii) the galvanic exchange method, (iii) ligand-induced conversion of bimetallic clusters to doped clusters, and (iv) intercluster reactions.As a foreign atom is able to occupy different positions within the structure of the parent cluster, we examine the structural relationship between the parent clusters and their different foreign-atom-doped clusters. We then show how doping enhances the stability, luminescence, and catalytic properties of clusters. The enhancement factor highly depends on the no. and nature of the foreign atoms, which can also alter the charge state of the parent cluster.Atomic-level doping of foreign atoms in the parent cluster is confirmed by high-resoln. electrospray ionization and matrix-assisted laser desorption ionization mass spectrometry techniques and single-crystal X-ray diffraction methods. The photophys. properties of the doped clusters are investigated using both time-dependent and steady-state luminescence and optical absorption spectroscopies.After presenting an overview of at.-level doping in metal clusters and demonstrating its importance for enriching the chem. and photophysics of clusters and extending their applications, we conclude this Account with a brief perspective on the field's future.
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957Negishi, Y.; Kurashige, W.; Niihori, Y.; Iwasa, T.; Nobusada, K. Isolation, structure, and stability of a dodecanethiolate-protected Pd1Au24 cluster. Phys. Chem. Chem. Phys. 2010, 12, 6219– 6225, DOI: 10.1039/b927175a957https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmvVWrs7o%253D&md5=497da89542b2b4d7359b52e818411e57Isolation, structure, and stability of a dodecanethiolate-protected Pd1Au24 clusterNegishi, Yuichi; Kurashige, Wataru; Niihori, Yoshiki; Iwasa, Takeshi; Nobusada, KatsuyukiPhysical Chemistry Chemical Physics (2010), 12 (23), 6219-6225CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)A dodecanethiolate-protected Pd1Au24(SC12H25)18 cluster, which is a mono-Pd-doped cluster of the well understood magic gold cluster Au25(SR)18, was isolated in high purity using solvent fractionation and high-performance liq. chromatog. (HPLC) after the prepn. of dodecanethiolate-protected palladium-gold bimetal clusters. The cluster thus isolated was identified as the neutral [Pd1Au24(SC12H25)18]0 from the retention time in reverse phase columns and by elemental analyses. The LDI mass spectrum of [Pd1Au24(SC12H25)18]0 indicates that [Pd1Au24(SC12H25)18]0 adopts a similar framework structure to Au25(SR)18, in which an icosahedral Au13 core is protected by six [-S-Au-S-Au-S-] oligomers. The optical absorption spectrum of [Pd1Au24(SC12H25)18]0 exhibits peaks at ∼690 and ∼620 nm, which is consistent with calcd. results on [Pd1Au24(SC1H3)18]0 in which the central gold atom of Au25(SC1H3)18 is replaced with Pd. These results strongly indicate that the isolated [Pd1Au24(SC12H25)18]0 has a core-shell [Pd1@Au24(SC12H25)18]0 structure in which the central Pd atom is surrounded by a frame of Au24(SC12H25)18. Expts. on the stability of the cluster showed that Pd1@Au24(SC12H25)18 is more stable against degrdn. in soln. and laser dissocn. than Au25(SC12H25)18. These results indicate that the doping of a central atom is a powerful method to increase the stability beyond the Au25(SR)18 cluster.
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958Kacprzak, K. A.; Lehtovaara, L.; Akola, J.; Lopez-Acevedo, O.; Häkkinen, H. A density functional investigation of thiolate-protected bimetal PdAu24(SR)18z clusters: Doping the superatom complex. Phys. Chem. Chem. Phys. 2009, 11, 7123– 7129, DOI: 10.1039/b904491d958https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXpslels70%253D&md5=6f938a77f85b0cfac037128e7f8849f7A density functional investigation of thiolate-protected bimetal PdAu24(SR)18z clusters: doping the superatom complexKacprzak, Katarzyna A.; Lehtovaara, Lauri; Akola, Jaakko; Lopez-Acevedo, Olga; Haekkinen, HannuPhysical Chemistry Chemical Physics (2009), 11 (33), 7123-7129CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Structure, electronic properties, optical absorption and charging properties of methylthiolate-protected bimetal PdAu24(SR)18z (R = Me) clusters with various charge states (-3 ≤z≤ +3) are investigated by using d. functional theory. The results are compared to properties of the well-understood singly anionic pure gold complex Au25(SR)18(-1). The at. structure of this all-gold complex can be written in a "divide-and-protect" way as Au13[Au2(SR)3]6(-1) where 6 v-shaped Au2(SR)3 ligands protect the close-to-icosahedral Au13 core and where eight delocalized metal electrons, derived from Au(6s) electrons, comprise a stable closed-shell 1S21P6"superatom" configuration in the core. We show that the di-anion PdAu24(SR)18(-2) is a corresponding eight-electron closed-shell species whereas the clusters PdAu24(SR)18z, -1 ≤z≤ +3, have holes in the 1P HOMO manifold. This indicates that the doping Pd atom remains close to the zero-valent 4d105s0 configuration and does not contribute electrons to the delocalized electron d. in the gold core. Structural optimization shows that the all-gold "divide-and-protect" structure motif is robust with respect to replacing the Au by Pd at the center of the core, at the surface of the core or in one of the protecting Au2(SR)3 ligands. However, optical absorption and the HOMO-LUMO and electrochem. gaps depend sensitively on the site of the doping Pd atom, which may turn out be useful for assigning the structure of PdAu24(SR)18 from exptl. data.
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959Jiang, D.-e.; Dai, S. From superatomic Au25(SR)18– to superatomic M@Au24(SR)18q core–shell clusters. Inorg. Chem. 2009, 48, 2720– 2722, DOI: 10.1021/ic8024588959https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitFymurg%253D&md5=caabf4b34c8fb0942609452f6b18c04dFrom Superatomic Au25(SR)18- to Superatomic M@Au24(SR)18q Core-Shell ClustersJiang, De-en; Da, ShengInorganic Chemistry (2009), 48 (7), 2720-2722CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)Au25(SR)18- belongs to a new type of superatom that features an icosahedral Au13 core-shell structure and a protective layer of six RS(Au-SR)2 motifs. This superatom has a magic no. of 8 free electrons that fully fill the 1s and 1p levels of the electron-shell model. By applying this superatom concept to the core-substitution chem. of Au25(SR)18-, we first scanned the periodic table for the potential core atom M by applying a simple rule derived from the 8-electron count and then optimized the selected candidates by d. functional theory calcns. to create many series of M@Au24(SR)18q core-shell nanoclusters. We found that 16 elements from groups 1, 2, and 10-14 of the periodic table can maintain both electronic and geometric structures of the original Au25(SR)18- magic cluster, indicating that the electron-counting rule based on the superatom concept is powerful in predicting viable M@Au24(SR)18q clusters. Our work opens up a promising area for exptl. exploration.
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960Qian, H.; Jiang, D.-e.; Li, G.; Gayathri, C.; Das, A.; Gil, R. R.; Jin, R. Monoplatinum doping of gold nanoclusters and catalytic application. J. Am. Chem. Soc. 2012, 134, 16159– 16162, DOI: 10.1021/ja307657a960https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlygtLnL&md5=c84987ca82307cb22766c05382024719Monoplatinum Doping of Gold Nanoclusters and Catalytic ApplicationQian, Huifeng; Jiang, De-en; Li, Gao; Gayathri, Chakicherla; Das, Anindita; Gil, Roberto R.; Jin, RongchaoJournal of the American Chemical Society (2012), 134 (39), 16159-16162CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)We report single-atom doping of gold nanoclusters (NCs), and its drastic effects on the optical, electronic, and catalytic properties, using the 25-atom system as a model. In our synthetic approach, a mixt. of Pt1Au24(SC2H4Ph)18 and Au25(SC2H4Ph)18 was produced via a size-focusing process, and then Pt1Au24(SC2H4Ph)18 NCs were obtained by selective decompn. of Au25(SC2H4Ph)18 in the mixt. with concd. H2O2 followed by purifn. via size-exclusion chromatog. Exptl. and theor. analyses confirmed that Pt1Au24(SC2H4Ph)18 possesses a Pt-centered icosahedral core capped by six Au2(SC2H4Ph)3 staples. The Pt1Au24(SC2H4Ph)18 cluster exhibits greatly enhanced stability and catalytic activity relative to Au25(SC2H4Ph)18 but a smaller energy gap (Eg ≈ 0.8 eV vs 1.3 eV for the homogold cluster).
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961Fields-Zinna, C. A.; Crowe, M. C.; Dass, A.; Weaver, J. E.; Murray, R. W. Mass spectrometry of small bimetal monolayer-protected clusters. Langmuir 2009, 25, 7704– 7710, DOI: 10.1021/la803865v961https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnt1Wrsr0%253D&md5=569f1f37d5f513ec63deccc78d9cf882Mass Spectrometry of Small Bimetal Monolayer-Protected ClustersFields-Zinna, Christina A.; Crowe, Matthew C.; Dass, Amala; Weaver, Joshua E. F.; Murray, Royce W.Langmuir (2009), 25 (13), 7704-7710CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)Monolayer-protected clusters were prepd. by procedures like those yielding Au25L18 (where L = -SCH2CH2Ph = -SC2Ph) but using, instead, mixts. of Au and Pd salts, as starting materials, with the intent of creating and characterizing Au25-xMxL18 clusters. Isolation of small nanoparticle product followed by partial ligand exchange to introduce thiolated poly(ethylene glycol) (SPEG = -S(CH2CH2O)5CH3) into the nanoparticle ligand shell enabled characterization of the Au25-xMxL18 content by pos. mode electrospray ionization mass spectrometry (ESI-MS). For synthetic feed mole ratios of Au:Pd of 9:1 and 13:12, electrospray spectra of the PEGylated MPCs showed that the reaction and isolation produce a mixt. of Au25(SC2Ph)18 and a mono-Pd nanoparticle Au24Pd(SC2Ph)18. A higher proportion of the mono-Pd nanoparticle is produced by the 13:12 mol ratio, and also when the thiol:metal ratio was lowered, according to ESI-MS and MALDI-TOF-MS. As the nanoparticle mixt. is enriched, by solvent fractionations, in Au24Pd(SC2Ph)18 relative to Au25(SC2Ph)18, the distinctive optical and electrochem. signatures of Au25(SC2Ph)18 are replaced by Au24Pd(SC2Ph)18 nanoparticle responses, which are very different, even though only one Au atom is replaced by a Pd atom.
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962Tofanelli, M. A.; Ni, T. W.; Phillips, B. D.; Ackerson, C. J. Crystal structure of the PdAu24(SR)180 superatom. Inorg. Chem. 2016, 55, 999– 1001, DOI: 10.1021/acs.inorgchem.5b02106962https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVGksr8%253D&md5=2e1ee7a93185d4cd252e3e67c68d792cCrystal Structure of the PdAu24(SR)180 SuperatomTofanelli, Marcus A.; Ni, Thomas W.; Phillips, Billy D.; Ackerson, Christopher J.Inorganic Chemistry (2016), 55 (3), 999-1001CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)The single-crystal X-ray structure of Pd-doped Au25(SR)18 was solved. The crystal structure reveals that in PdAu24(SR)18, the Pd atom is localized only to the centroid of the Au25(SR)18 cluster. This single-crystal X-ray structure shows that PdAu24(SR)180 is well conceptualized with the superatom theory. The PdAu24(SR)180 charge state is isoelectronic with Au25(SR)18+1 as detd. by a first order Jahn-Teller effect of similar magnitude and by electrochem. comparison. The previously reported increased stability of PdAu24(SR)18 can be rationalized in terms of Pd-Au bonds that are shorter than the Au-Au bonds in Au25(SR)18.
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963Negishi, Y.; Igarashi, K.; Munakata, K.; Ohgake, W.; Nobusada, K. Palladium doping of magic gold cluster Au38(SC2H4Ph)24: Formation of Pd2Au36(SC2H4Ph)24 with higher stability than Au38(SC2H4Ph)24. Chem. Commun. 2012, 48, 660– 662, DOI: 10.1039/C1CC15765E963https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1Srur%252FM&md5=1889c0736e65ab7a431cd1f1f57541cdPalladium doping of magic gold cluster Au38(SC2H4Ph)24: formation of Pd2Au36(SC2H4Ph)24 with higher stability than Au38(SC2H4Ph)24Negishi, Yuichi; Igarashi, Kozue; Munakata, Kenta; Ohgake, Wataru; Nobusada, KatsuyukiChemical Communications (Cambridge, United Kingdom) (2012), 48 (5), 660-662CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A phenylethanethiolate-protected Pd2Au36(SC2H4Ph)24 cluster, which is a two-Pd atom-doped cluster of the well studied magic gold cluster Au38(SC2H4Ph)24, was synthesized in high purity and its stability was studied. Pd2Au36(SC2H4Ph)24 is more stable than Au38(SC2H4Ph)24 against degrdn. in soln. and core etching by thiols.
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964Liu, X.; Yuan, J.; Yao, C.; Chen, J.; Li, L.; Bao, X.; Yang, J.; Wu, Z. Crystal and solution photoluminescence of MAg24(SR)18 (M = Ag/Pd/Pt/Au) nanoclusters and some implications for the photoluminescence mechanisms. J. Phys. Chem. C 2017, 121, 13848– 13853, DOI: 10.1021/acs.jpcc.7b01730964https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpsVeqt78%253D&md5=d73c920055df21ddaa3e1faa5fc43a16Crystal and Solution Photoluminescence of MAg24(SR)18(M = Ag/Pd/Pt/Au) Nanoclusters and Some Implications for the Photoluminescence MechanismsLiu, Xu; Yuan, Jinyun; Yao, Chuanhao; Chen, Jishi; Li, Lingling; Bao, Xiaoli; Yang, Jinlong; Wu, ZhikunJournal of Physical Chemistry C (2017), 121 (25), 13848-13853CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)MAg24(SR)18 (M = Ag/Pd/Pt/Au) nanoclusters (NCs) with similar core-inner shell-outer shell structures were prepd., and their crystal and soln. luminescence was studied. The core Ag atom replacement by the Pd/Pt/Au atom obviously tunes the geometric and electronic structures of Ag25(SR)18 NC. The crystal luminescence intensities sequence hints a core-atom-directing charge transfer from the ligands to the metal kernels. Both the calcd. NPA charge and the measured Aginnershell-Sterminal bond length support the proposed mechanism. Further expts. show the solvent influence on the NCs luminescence supported by the blue-shift of emissions of MAg24(SR)18 NCs and the solvent-dependent luminescence intensity sequences. Esp., for PtAg24(SR)18, the quantum yield is almost 100-fold greater in MeCN (18.6%) than in CH2Cl2 (0.2%). However, the emission wavelengths of NCs are barely influenced by the solvent type. This work indicates the importance of the core atom and the solvent to the luminescence of core-inner shell-outer shell Ag NCs, having important implications for the luminescence mechanisms and tuning of noble metal nanoparticles.
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965Yan, J.; Su, H.; Yang, H.; Malola, S.; Lin, S.; Häkkinen, H.; Zheng, N. Total structure and electronic structure analysis of doped thiolated silver [MAg24(SR)18]2– (M = Pd, Pt) clusters. J. Am. Chem. Soc. 2015, 137, 11880– 11883, DOI: 10.1021/jacs.5b07186965https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVygs7jK&md5=f3ce7b369dbd8949b1559419b3c6bc18Total Structure and Electronic Structure Analysis of Doped Thiolated Silver [MAg24(SR)18]2- (M = Pd, Pt) ClustersYan, Juanzhu; Su, Haifeng; Yang, Huayan; Malola, Sami; Lin, Shuichao; Hakkinen, Hannu; Zheng, NanfengJournal of the American Chemical Society (2015), 137 (37), 11880-11883CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)With the incorporation of Pd or Pt atoms, thiolated Ag-rich 25-metal-atom nanoclusters were successfully prepd. and structurally characterized for the first time. With a compn. of [PdAg24(SR)18]2- or [PtAg24(SR)18]2-, the obtained 25-metal-atom nanoclusters have a metal framework structure similar to that of widely investigated Au25(SR)18. In both clusters, a M@Ag12 (M = Pd, Pt) core is capped by six distorted dimeric -RS-Ag-SR-Ag-SR- units. However, the silver-thiolate overlayer gives rise to a geometric chirality at variance to Au25(SR)18. The effect of doping on the electronic structure was studied through measured optical absorption spectra and ab initio anal. This work demonstrates that modulating electronic structures by transition-metal doping is expected to provide effective means to manipulate electronic, optical, chem., and catalytic properties of thiolated noble metal nanoclusters.
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966Bootharaju, M. S.; Joshi, C. P.; Parida, M. R.; Mohammed, O. F.; Bakr, O. M. Templated atom-precise galvanic synthesis and structure elucidation of a [Ag24Au(SR)18]− nanocluster. Angew. Chem., Int. Ed. 2016, 55, 922– 926, DOI: 10.1002/anie.201509381966https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFenurvN&md5=f177df90293e32d87abcd52040997038Templated Atom-Precise Galvanic Synthesis and Structure Elucidation of a [Ag24Au(SR)18]- NanoclusterBootharaju, Megalamane S.; Joshi, Chakra P.; Parida, Manas R.; Mohammed, Omar F.; Bakr, Osman M.Angewandte Chemie, International Edition (2016), 55 (3), 922-926CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Synthesis of atom-precise alloy nanoclusters with uniform compn. is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag24Au(SR)18]- cluster (SR: thiolate) using a pure [Ag25(SR)18]- cluster as a template. Conversely, the direct synthesis of Ag24Au cluster leads to a mixt. of [Ag25-xAux(SR)18]-, x=1-8. Mass spectrometry and crystallog. of [Ag24Au(SR)18]- reveal the presence of the Au heteroatom at the Ag25 center, forming Ag24Au. The successful exchange of the central Ag of Ag25 with Au causes perturbations in the Ag25 crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag25 and Ag24Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single-atom level.
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967Bootharaju, M. S.; Joshi, C. P.; Parida, M. R.; Mohammed, O. F.; Bakr, O. M. Innentitelbild: Templated atom-precise galvanic synthesis and structure elucidation of a [Ag24Au(SR)18]− nanocluster (Angew. Chem. 3/2016). Angew. Chem. 2016, 128, 834– 834, DOI: 10.1002/ange.201511258There is no corresponding record for this reference.
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968Van Der Linden, M.; Van Bunningen, A. J.; Amidani, L.; Bransen, M.; Elnaggar, H.; Glatzel, P.; Meijerink, A.; De Groot, F. M. Single Au atom doping of silver nanoclusters. ACS Nano 2018, 12, 12751– 12760, DOI: 10.1021/acsnano.8b07807968https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1CktrrL&md5=30b1a8ff037c73531341eab63e36ad05Single Au Atom Doping of Silver Nanoclustersvan der Linden, Marte; van Bunningen, Arnoldus J.; Amidani, Lucia; Bransen, Maarten; Elnaggar, Hebatalla; Glatzel, Pieter; Meijerink, Andries; de Groot, Frank M. F.ACS Nano (2018), 12 (12), 12751-12760CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Ag29 nanoclusters capped with lipoic acid (LA) can be doped with Au. The doped clusters show enhanced stability and increased luminescence efficiency. The authors attribute the higher quantum yield to an increase in the rate of radiative decay. With mass spectrometry, the Au-doped clusters consist predominantly of Au1Ag28(LA)123-. The clusters were characterized using x-ray absorption spectroscopy at the Au L3-edge. Both the extended absorption fine structure (EXAFS) and the near edge structure (XANES) in combination with electronic structure calcns. confirm that the Au dopant is preferentially located in the center of the cluster. A useful XANES spectrum can be recorded for lower concns., or in shorter time, than the more commonly used EXAFS. This makes XANES a valuable tool for structural characterization.
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969Khatun, E.; Bose, S.; Jash, M.; Pradeep, T. Atomically precise cluster-based white light emitters. J. Chem. Sci. 2018, 130, 147, DOI: 10.1007/s12039-018-1559-4There is no corresponding record for this reference.
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970Mishra, D.; Lobodin, V.; Zhang, C.; Aldeek, F.; Lochner, E.; Mattoussi, H. Gold-doped silver nanoclusters with enhanced photophysical properties. Phys. Chem. Chem. Phys. 2018, 20, 12992– 13007, DOI: 10.1039/C7CP08682B970https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXnslSmtr8%253D&md5=135cc41f78b198c5636fe102ecb8f3a0Gold-doped silver nanoclusters with enhanced photophysical propertiesMishra, Dinesh; Lobodin, Vladislav; Zhang, Chengqi; Aldeek, Fadi; Lochner, Eric; Mattoussi, HediPhysical Chemistry Chemical Physics (2018), 20 (18), 12992-13007CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We detail the characterization of atomically precise, luminescent silver and gold bimetallic nanoclusters (Ag and AgAuNCs) grown in the presence of bidentate lipoic acid (LA, the oxidized form) and dihydrolipoic acid (DHLA, the reduced form) ligands. We found that while doping AuNCs with Ag or Cu precursors using up to a 50% molar fraction (during growth) did not lead to any photoluminescence enhancement, doping of AgNCs with Au resulted in a six-fold enhancement of the PL emission compared to undoped AgNCs. The effect of doping is also reflected in the optical absorption and PL excitation spectra of the gold-doped NCs (AgAuNCs), where a clear blue shift in the absorbance features with respect to the pure AgNCs has been measured. Mass spectrometry measurements using ESI-MS showed that the AgNCs and Au-doped AgNCs had the compns. Ag29(DHLA)12 and Ag28Au(DHLA)12, resp. The bimetallic nature of the AgAuNC cores was further supported by XPS measurements. Data showed that the binding energies of the Ag and Au atoms measured from the nanoclusters were shifted with respect to those of the Ag and Au metals. Furthermore, the change in the Ag binding energy was affected by the presence of Au atoms. DOSY-NMR measurements performed on both sets of nanoclusters yielded no change in the hydrodynamic radius measured for either set of NCs when capped with the same ligands.
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971Soldan, G.; Aljuhani, M. A.; Bootharaju, M. S.; AbdulHalim, L. G.; Parida, M. R.; Emwas, A. H.; Mohammed, O. F.; Bakr, O. M. Gold doping of silver nanoclusters: A 26-fold enhancement in the luminescence quantum yield. Angew. Chem., Int. Ed. 2016, 55, 5749– 5753, DOI: 10.1002/anie.201600267971https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XlvVagt7c%253D&md5=8e803fba2570f61d6cee38e140c7fedcGold Doping of Silver Nanoclusters: A 26-Fold Enhancement in the Luminescence Quantum YieldSoldan, Giada; Aljuhani, Maha A.; Bootharaju, Megalamane S.; AbdulHalim, Lina G.; Parida, Manas R.; Emwas, Abdul-Hamid; Mohammed, Omar F.; Bakr, Osman M.Angewandte Chemie, International Edition (2016), 55 (19), 5749-5753CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)A high quantum yield (QY) of photoluminescence (PL) in nanomaterials is necessary for a wide range of applications. Unfortunately, the weak PL and moderate stability of atomically precise silver nanoclusters (NCs) suppress their utility. Herein, we accomplished a ≥26-fold PL QY enhancement of the Ag29(BDT)12(TPP)4 cluster (BDT: 1,3-benzenedithiol; TPP: triphenylphosphine) by doping with a discrete no. of Au atoms, producing Ag29-xAux(BDT)12(TPP)4, x=1-5. The Au-doped clusters exhibit an enhanced stability and an intense red emission around 660 nm. Single-crystal XRD, mass spectrometry, optical, and NMR spectroscopy shed light on the PL enhancement mechanism and the probable locations of the Au dopants within the cluster.
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972Kang, X.; Zhou, M.; Wang, S.; Jin, S.; Sun, G.; Zhu, M.; Jin, R. The tetrahedral structure and luminescence properties of Bi-metallic Pt1Ag28(SR)18(PPh3)4 nanocluster. Chem. Sci. 2017, 8, 2581– 2587, DOI: 10.1039/C6SC05104A972https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXksl2hug%253D%253D&md5=f6f3980086e5c40bb4d0b51e035dde2aThe tetrahedral structure and luminescence properties of bi-metallic Pt1Ag28(SR)18(PPh3)4 nanoclusterKang, Xi; Zhou, Meng; Wang, Shuxin; Jin, Shan; Sun, Guodong; Zhu, Manzhou; Jin, RongchaoChemical Science (2017), 8 (4), 2581-2587CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)The at.-structure characterization of alloy nanoclusters (NCs) remains challenging but is crucial in order to understand the synergism and develop new applications based upon the distinct properties of alloy NCs. Herein, we report the synthesis and X-ray crystal structure of the Pt1Ag28(S-Adm)18(PPh3)4 nanocluster with a tetrahedral shape. Pt1Ag28 was synthesized by reacting Pt1Ag24(SPhMe2)18 simultaneously with Adm-SH (1-adamantanethiol) and PPh3 ligands. A tetrahedral structure is found in the metal framework of Pt1Ag28 NC and an overall surface shell (Ag16S18P4), as well as discrete Ag4S6P1 motifs. The Pt1Ag12 kernel adopts a face-centered cubic (FCC) arrangement, which is obsd. for the first time in alloy nanoclusters in contrast to the commonly obsd. icosahedral structure of homogold and homosilver NCs. The Pt1Ag28 nanocluster exhibits largely enhanced photoluminescence (quantum yield QY = 4.9%, emission centered at ∼672 nm), whereas the starting material (Pt1Ag24 NC) is only weakly luminescent (QY = 0.1%). Insights into the nearly 50-fold enhancement of luminescence were obtained via the anal. of electronic dynamics. This study demonstrates the at.-level tailoring of the alloy nanocluster properties by controlling the structure.
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973Bootharaju, M. S.; Kozlov, S. M.; Cao, Z.; Harb, M.; Parida, M. R.; Hedhili, M. N.; Mohammed, O. F.; Bakr, O. M.; Cavallo, L.; Basset, J.-M. Direct versus ligand-exchange synthesis of [PtAg28(BDT)12(TPP)4]4– nanoclusters: Effect of a single-atom dopant on the optoelectronic and chemical properties. Nanoscale 2017, 9, 9529– 9536, DOI: 10.1039/C7NR02844J973https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXps1ensro%253D&md5=67fae01d8975685144d9c8e99e75a6e1Direct versus ligand-exchange synthesis of [PtAg28(BDT)12(TPP)4]4- nanoclusters: effect of a single-atom dopant on the optoelectronic and chemical propertiesBootharaju, Megalamane S.; Kozlov, Sergey M.; Cao, Zhen; Harb, Moussab; Parida, Manas R.; Hedhili, Mohamed N.; Mohammed, Omar F.; Bakr, Osman M.; Cavallo, Luigi; Basset, Jean-MarieNanoscale (2017), 9 (27), 9529-9536CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Heteroatom doping of atomically precise nanoclusters (NCs) often yields a mixt. of doped and undoped products of single-atom difference, whose sepn. is extremely difficult. To overcome this challenge, novel synthesis methods are required to offer monodisperse doped NCs. For instance, the direct synthesis of PtAg28 NCs produces a mixt. of [Ag29(BDT)12(TPP)4]3- and [PtAg28(BDT)12(TPP)4]4- NCs (TPP: triphenylphosphine; BDT: 1,3-benzenedithiolate). Here, we designed a ligand-exchange (LE) strategy to synthesize single-sized, Pt-doped, superat. Ag NCs [PtAg28(BDT)12(TPP)4]4- by LE of [Pt2Ag23Cl7(TPP)10] NCs with BDTH2 (1,3-benzenedithiol). The doped NCs were thoroughly characterized by optical and photoelectron spectroscopy, mass spectrometry, total electron count, and time-dependent d. functional theory (TDDFT). We show that the Pt dopant occupies the center of the PtAg28 cluster, modulates its electronic structure and enhances its photoluminescence intensity and excited-state lifetime, and also enables solvent interactions with the NC surface. Furthermore, doped NCs showed unique reactivity with metal ions - the central Pt atom of PtAg28 could not be replaced by Au, unlike the central Ag of Ag29 NCs. The achieved synthesis of single-sized PtAg28 clusters will facilitate further applications of the LE strategy for the exploration of novel multimetallic NCs.
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974Li, Q.; Lambright, K. J.; Taylor, M. G.; Kirschbaum, K.; Luo, T.-Y.; Zhao, J.; Mpourmpakis, G.; Mokashi-Punekar, S.; Rosi, N. L.; Jin, R. Reconstructing the surface of gold nanoclusters by cadmium doping. J. Am. Chem. Soc. 2017, 139, 17779– 17782, DOI: 10.1021/jacs.7b11491974https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVOit73P&md5=f91b82d39020d45a6eeec0caa113ae0bReconstructing surface of gold nanoclusters by cadmium dopingLi, Qi; Lambright, Kelly J.; Taylor, Michael G.; Kirschbaum, Kristin; Luo, Tian-Yi; Zhao, Jianbo; Mpourmpakis, Giannis; Mokashi-Punekar, Soumitra; Rosi, Nathaniel L.; Jin, RongchaoJournal of the American Chemical Society (2017), 139 (49), 17779-17782CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Atomically precise metal nanoclusters with tailored surface structures are important for both fundamental studies and practical applications. The development of new methods for tailoring the surface structure in a controllable manner has long been sought. In this work, we report surface reconstruction induced by cadmium doping into the [Au23(SR)16]- (R = cyclohexyl) nanocluster, in which two neighboring surface Au at. sites "coalesce" into one Cd at. site and, accordingly, a new bimetal nanocluster, [Au19Cd2(SR)16]-, is produced. Interestingly, a Cd(S-Au-S)3 "paw-like" surface motif is obsd. for the first time in nanocluster structures. In such a motif, the Cd atom acts as a junction which connects three monomeric -S-Au-S- motifs. D. functional theory calcns. are performed to understand the two unique Cd locations. Furthermore, we demonstrate different doping modes when the [Au23(SR)16]- nanocluster is doped with different metals (Cu, Ag), including (i) simple substitution and (ii) total structure transformation, as opposed to surface reconstruction for Cd doping. This work greatly expands doping chem. for tailoring the structures of nanoclusters and is expected to open new avenues for designing nanoclusters with novel surface structures using different dopants.
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975Liao, L.; Zhou, S.; Dai, Y.; Liu, L.; Yao, C.; Fu, C.; Yang, J.; Wu, Z. Mono-mercury doping of Au25 and the HOMO/LUMO energies evaluation employing differential pulse voltammetry. J. Am. Chem. Soc. 2015, 137, 9511– 9514, DOI: 10.1021/jacs.5b03483975https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtF2ltrrE&md5=f13e2e8eb1f42c7f7fb583dd9cfa8410Mono-Mercury Doping of Au25 and the HOMO/LUMO Energies Evaluation Employing Differential Pulse VoltammetryLiao, Lingwen; Zhou, Shiming; Dai, Yafei; Liu, Liren; Yao, Chuanhao; Fu, Cenfeng; Yang, Jinlong; Wu, ZhikunJournal of the American Chemical Society (2015), 137 (30), 9511-9514CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Controlling the bimetal nanoparticle with at. monodispersity is still challenging. Herein, a monodisperse bimetal nanoparticle was synthesized in 25% yield (on gold atom basis) by an unusual replacement method. The formula of the nanoparticle is Au24Hg1(PET)18 (PET: phenylethanethiolate) by high-resoln. ESI-MS spectrometry in conjunction with multiple analyses including XPS and TGA. X-ray single-crystal diffraction reveals that the structure of Au24Hg1(PET)18 remains the structural framework of Au25(PET)18 with one of the outer-shell gold atoms replaced by one Hg atom, which is further supported by theor. calcns. and exptl. results as well. Importantly, differential pulse voltammetry (DPV) is 1st employed to est. the highest occupied mol. orbit (HOMO) and the lowest unoccupied mol. orbit (LUMO) energies of Au24Hg1(PET)18 based on previous calcns.
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976Yao, C.; Lin, Y.-j.; Yuan, J.; Liao, L.; Zhu, M.; Weng, L.-h.; Yang, J.; Wu, Z. Mono-cadmium vs mono-mercury doping of Au25 nanoclusters. J. Am. Chem. Soc. 2015, 137, 15350– 15353, DOI: 10.1021/jacs.5b09627976https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFSmtb7F&md5=2cfde4145db071971db70f1ddfe93d5fMono-cadmium vs Mono-mercury Doping of Au25 NanoclustersYao, Chuanhao; Lin, Yue-jian; Yuan, Jinyun; Liao, Lingwen; Zhu, Min; Weng, Lin-hong; Yang, Jinlong; Wu, ZhikunJournal of the American Chemical Society (2015), 137 (49), 15350-15353CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Controlling the dopant type, no., and position in doped metal nanoclusters (nanoparticles) is crucial but challenging. In the work described herein, the authors successfully achieved the mono-cadmium doping of Au25 nanoclusters, and revealed using x-ray crystallog. (of [Au24Cd(SCH2CH2Ph)18]·2C7H8) in combination with theor. calcns. that one of the inner-shell gold atoms of Au25 was replaced by a Cd atom. The doping mode is distinctly different from that of mono-mercury doping, where one of the outer-shell Au atoms was replaced by a Hg atom. Au24Cd is readily transformed to Au24Hg, while the reverse (transformation from Au24Hg to Au24Cd) is forbidden under the investigated conditions.
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977Wang, Y.; Liu, Y.-H.; Zhang, Y.; Wang, F.; Kowalski, P. J.; Rohrs, H. W.; Loomis, R. A.; Gross, M. L.; Buhro, W. E. Isolation of the Magic-Size CdSe Nanoclusters [(CdSe)13(n-octylamine)13] and [(CdSe)13(oleylamine)13]. Angew. Chem., Int. Ed. 2012, 51, 6154– 6157, DOI: 10.1002/anie.201202380977https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XmvVCjsrk%253D&md5=4f53bfc77613289f37a489f5bc8328cfIsolation of the Magic-Size CdSe Nanoclusters [(CdSe)13(n-octylamine)13] and [(CdSe)13(oleylamine)13]Wang, Yuanyuan; Liu, Yi-Hsin; Zhang, Ying; Wang, Fudong; Kowalski, Paul J.; Rohrs, Henry W.; Loomis, Richard A.; Gross, Michael L.; Buhro, William E.Angewandte Chemie, International Edition (2012), 51 (25), 6154-6157, S6154/1-S6154/15CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)(CdSe)13 nanoclusters have been recently reported as intermediates in the synthesis of CdSe quantum belts (nano-ribbons). A lamellar intermediate phase collected from the quantum-belt synthesis is [(CdSe)13(M-OCtylamine)13], the smallest, discrete, magic-size nanocluster of CdSe that has been obsd. Free, sol. [(CdSe)13(Oleylamine)13] nanoclusters are released from the insol. [(CdSe)13(n-octylamine)13] upon ligand exchange. Nanoclusters of (CdSe)13 are generated by reaction of cadmium acetate dihydrate, [Cd(OAc)2(H2O)2], with selenourea [H2NC(Se)NH2] in n-octylamine solvent at room temp. Combination of CdX2 compds. (X = halide,'1'13' OAc'1') with n-octylamine results in the spontaneous formation of lamellar mesophases consisting of CdX2 layers sepd. by n-octylamine bilayers. Addn. of selenourea generates a mixt. of CdSe nanoclusters that converts completely into (CdSe)13,. A white ppt. is deposited, which we now show to be [(CdSe)13(/i-octylamine)13].
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978Liu, Y. H.; Wang, F.; Wang, Y.; Gibbons, P. C.; Buhro, W. E. Lamellar assembly of cadmium selenide nanoclusters into quantum belts. J. Am. Chem. Soc. 2011, 133, 17005– 17013, DOI: 10.1021/ja206776g978https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1ClsbvP&md5=af6c47a939df2bfba4e688c2b3438cc2Lamellar Assembly of Cadmium Selenide Nanoclusters into Quantum BeltsLiu, Yi-Hsin; Wang, Fudong; Wang, Yuanyuan; Gibbons, Patrick C.; Buhro, William E.Journal of the American Chemical Society (2011), 133 (42), 17005-17013CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Here, we elucidate a double-lamellar-template pathway for the formation of CdSe quantum belts. The lamellar templates form initially by dissoln. of the CdX2 precursors in the n-octylamine solvent. Exposure of the precursor templates to selenourea at room temp. ultimately affords (CdSe)13 nanoclusters entrained within the double-lamellar templates. Upon heating, the nanoclusters are transformed to CdSe quantum belts having widths, lengths, and thicknesses that are predetd. by the dimensions within the templates. This template synthesis is responsible for the excellent optical properties exhibited by the quantum belts. We propose that the templated-growth pathway is responsible for the formation of the various flat, colloidal nanocrystals recently discovered, including nanoribbons, nanoplatelets, nanosheets, and nanodisks.
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979Hsieh, T.-E.; Yang, T.-W.; Hsieh, C.-Y.; Huang, S.-J.; Yeh, Y.-Q.; Chen, C.-H.; Li, E. Y.; Liu, Y.-H. Unraveling the structure of magic-size (CdSe)13 cluster pairs. Chem. Mater. 2018, 30, 5468– 5477, DOI: 10.1021/acs.chemmater.8b02468979https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtlCnsbbM&md5=af47530237d2cf870922909732f24d86Unraveling the Structure of Magic-Size (CdSe)13 Cluster PairsHsieh, Tzung-En; Yang, Ta-Wei; Hsieh, Cheng-Yin; Huang, Shing-Jong; Yeh, Yi-Qi; Chen, Ching-Hsiang; Li, Elise Y.; Liu, Yi-HsinChemistry of Materials (2018), 30 (15), 5468-5477CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)Cadmium selenide is a II-VI semiconductor model system known for its nanoparticle prepn., growth mechanism, luminescence properties, and quantum confinement studies. For the past 2 decades, various thermodynamically stable "magic-size nanoclusters (MSCs)" of CdSe have been obsd., isolated, and theor. calcd. Nevertheless, none of the proposed structures were exptl. confirmed due to the small crystal domains beyond the diffraction limit. With a combination of nondestructive SAXS, WAXS, XRD, XPS, EXAFS, and MAS NMR techniques, we were able to verify the phase transformation, shape, size dimension, local bonding, and chem. environments of (CdSe)13 nanoclusters, which are indicative of a paired cluster model. These exptl. results are consistent with the size, shape, bond lengths, dipole moment, and charge densities of the proposed "paired-tubular geometry" predicted by computational approaches. In this article, we revisit the formation pathway of the mysterious (CdSe)13 nanoclusters and propose a paired cluster structure model for better understanding of II-VI semiconductor nanoclusters.
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980Yu, J. H.; Liu, X.; Kweon, K. E.; Joo, J.; Park, J.; Ko, K.-T.; Lee, D. W.; Shen, S.; Tivakornsasithorn, K.; Son, J. S. Giant Zeeman splitting in nucleation-controlled doped CdSe:Mn2+ quantum nanoribbons. Nat. Mater. 2010, 9, 47– 53, DOI: 10.1038/nmat2572980https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFOnsrrF&md5=e4c63402a3665377e1e141b4bd302229Giant Zeeman splitting in nucleation-controlled doped CdSe:Mn2+ quantum nanoribbonsYu, Jung Ho; Liu, Xinyu; Kweon, Kyoung Eun; Joo, Jin; Park, Jiwon; Ko, Kyung-Tae; Lee, Dong Won; Shen, Shaoping; Tivakornsasithorn, Kritsanu; Son, Jae Sung; Park, Jae-Hoon; Kim, Young-Woon; Hwang, Gyeong S.; Dobrowolska, Margaret; Furdyna, Jacek K.; Hyeon, TaeghwanNature Materials (2010), 9 (1), 47-53CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Doping of semiconductor nanocrystals by transition-metal ions has attracted tremendous attention owing to their nanoscale spintronic applications. Such doping is, however, difficult to achieve in low-dimensional strongly quantum confined nanostructures by conventional growth procedures. The incorporation of manganese ions up to 10% into CdSe quantum nanoribbons can be readily achieved by a nucleation-controlled doping process. The cation-exchange reaction of (CdSe)13 clusters with Mn2+ ions governs the Mn2+ incorporation during the nucleation stage. This highly efficient Mn2+ doping of the CdSe quantum nanoribbons results in giant exciton Zeeman splitting with an effective g-factor of ∼600, the largest value seen so far in dild. magnetic semiconductor nanocrystals. Also, the sign of the s-d exchange is inverted to neg. owing to the exceptionally strong quantum confinement in the authors' nanoribbons. The nucleation-controlled doping strategy demonstrated here thus opens the possibility of doping various strongly quantum confined nanocrystals for diverse applications.
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981Yang, J.; Fainblat, R.; Kwon, S. G.; Muckel, F.; Yu, J. H.; Terlinden, H.; Kim, B. H.; Iavarone, D.; Choi, M. K.; Kim, I. Y. Route to the smallest doped semiconductor: Mn2+-doped (CdSe)13 clusters. J. Am. Chem. Soc. 2015, 137, 12776– 12779, DOI: 10.1021/jacs.5b07888981https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1ajsb7O&md5=46556fbec1ac8be691dfa5bda43cbb6aRoute to the Smallest Doped Semiconductor: Mn2+-Doped (CdSe)13 ClustersYang, Jiwoong; Fainblat, Rachel; Kwon, Soon Gu; Muckel, Franziska; Yu, Jung Ho; Terlinden, Hendrik; Kim, Byung Hyo; Iavarone, Dino; Choi, Moon Kee; Kim, In Young; Park, Inchul; Hong, Hyo-Ki; Lee, Jihwa; Son, Jae Sung; Lee, Zonghoon; Kang, Kisuk; Hwang, Seong-Ju; Bacher, Gerd; Hyeon, TaeghwanJournal of the American Chemical Society (2015), 137 (40), 12776-12779CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Doping semiconductor nanocrystals with magnetic transition-metal ions has attracted fundamental interest to obtain a nanoscale dil. magnetic semiconductor, which has unique spin exchange interaction between magnetic spin and exciton. So far, the study on the doped semiconductor NCs has usually been conducted with NCs with larger than 2 nm because of synthetic challenges. Herein, we report the synthesis and characterization of Mn2+-doped (CdSe)13 clusters, the smallest doped semiconductors. In this study, single-sized doped clusters are produced in large scale. Despite their small size, these clusters have semiconductor band structure instead of that of mols. Surprisingly, the clusters show multiple excitonic transitions with different magneto-optical activities, which can be attributed to the fine structure splitting. Magneto-optically active states exhibit giant Zeeman splittings up to elevated temps. (128 K) with large g-factors of 81(±8) at 4 K. Our results present a new synthetic method for doped clusters and facilitate the understanding of doped semiconductor at the boundary of mols. and quantum nanostructure.
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982Muckel, F.; Yang, J.; Lorenz, S.; Baek, W.; Chang, H.; Hyeon, T.; Bacher, G.; Fainblat, R. Digital doping in magic-sized CdSe clusters. ACS Nano 2016, 10, 7135– 7141, DOI: 10.1021/acsnano.6b03348982https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFKrsL%252FF&md5=7589e98e346f78bb92875ec65085bc04Digital Doping in Magic-Sized CdSe ClustersMuckel, Franziska; Yang, Jiwoong; Lorenz, Severin; Baek, Woonhyuk; Chang, Hogeun; Hyeon, Taeghwan; Bacher, Gerd; Fainblat, RachelACS Nano (2016), 10 (7), 7135-7141CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Magic-sized semiconductor clusters represent an exciting class of materials located at the boundary between quantum dots and mols. It is expected that replacing single atoms of the host crystal with individual dopants in a 1-by-one fashion can lead to unique modifications of the material properties. Here, the authors demonstrate the dependence of the magneto-optical response of (CdSe)13 clusters on the discrete no. of Mn2+ ion dopants. Using time-of-flight mass spectrometry, the authors are able to distinguish undoped, monodoped, and bidoped cluster species, allowing for an extn. of the relative amt. of each species for a specific av. doping concn. A giant magneto-optical response is obsd. up to room temp. with clear evidence that exclusively monodoped clusters are magneto-optically active, whereas the Mn2+ ions in bidoped clusters couple antiferromagnetically and are magneto-optically passive. Mn2+-doped clusters therefore represent a system where magneto-optical functionality is caused by solitary dopants, which might be beneficial for future solotronic applications.
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983Palencia, C.; Yu, K.; Boldt, K. The future of colloidal semiconductor magic-size clusters. ACS Nano 2020, 14, 1227– 1235, DOI: 10.1021/acsnano.0c00040983https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhvFegs70%253D&md5=9b81d754f839c9d8be278d473855fc9bThe Future of Colloidal Semiconductor Magic-Size ClustersPalencia, Cristina; Yu, Kui; Boldt, KlausACS Nano (2020), 14 (2), 1227-1235CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. Atomically defined, zero-dimensional magic-size clusters play pivotal roles in the nucleation and growth of semiconductor nanocrystals. Thus, they provide new opportunities to understand and to control nucleation and growth reactions beyond classical nucleation theory and to employ these reactions in the colloidal synthesis of increasingly complex and anisotropic nanomaterials with at. level monodispersity. Both challenges require reliable detn. of the exact structure and size of these ultrasmall and metastable nanoclusters. In this Perspective, we review and discuss the current challenges in analytics of magic-size clusters, in elucidating their formation mechanism, and in using them as next-generation reagents in colloidal chem.
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984Lebon, A.; Aguado, A.; Vega, A. A new magnetic superatom:. Phys. Chem. Chem. Phys. 2015, 17, 28033– 28043, DOI: 10.1039/C4CP03753G984https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhslOisLzI&md5=1b28f3009f79d4b2f9ea7ba65ee3400eA new magnetic superatom: Cr@Zn17Lebon, Alexandre; Aguado, Andres; Vega, AndresPhysical Chemistry Chemical Physics (2015), 17 (42), 28033-28043CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)We demonstrate, by means of fully unconstrained d. functional theory calcns., that cluster Zn17 endohedrally doped with a Cr impurity can be qualified as a magnetic superalkali cluster. We explain the origin of its high stability, its low vertical ionization potential and its high total spin magnetic moment which amts. to 6 μB, exactly the same value as that of the isolated Cr atom. With the aim of exploring the possibility of designing a bistable magnetic nanoparticle, with a corresponding inter-unit exchange coupling, we also consider the assembling of two such units through different contact regions and in different magnetic configurations. Furthermore, we analyze up to which extent is the Zn shell able to preserve the electronic properties of the embedded Cr atom, both against coalescence of the two superatoms forming the magnetically bistable nanoparticle, and upon the adsorption of an O2 mol. or even under an oversatd. O2 atmosphere. Our results are discussed not only emphasizing the fundamental phys. and chem. aspects, but also with an eye on the new prospects that those Cr@Zn17 magnetic superalkali clusters (and others of similar kind) may open in spintronics-, mol. electronics- or biomedical-applications.
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985Kumar, V. High symmetry Nbn and Tan (n = 12, 15, and 17) clusters: High magnetic moments and the finding of superatoms with doping. Comput. Theor. Chem. 2013, 1021, 149– 154, DOI: 10.1016/j.comptc.2013.07.003985https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVWqs7%252FO&md5=3cbeb0a1792329d2d8c34c7e411d1878High symmetry Nbn and Tan (n = 12, 15, and 17) clusters: High magnetic moments and the finding of superatoms with dopingKumar, VijayComputational & Theoretical Chemistry (2013), 1021 (), 149-154CODEN: CTCOA5; ISSN:2210-271X. (Elsevier B.V.)Using ab initio calcns., we study Nbn and Tan clusters with n = 12, 15, and 17 and find superatoms made of transition metals. Nb12 and Ta12 have an empty cage icosahedral structure. Neutral Ta12 has icosahedral symmetry and 2 μB magnetic moments while the cage for Nb12 is slightly distorted and has no magnetic moment. These clusters behave like a divalent superatom. Accordingly an oxygen atom interacts exohedrally on a 3-fold site of the icosahedral cage like an MgO mol. and leaves the cage intact while Fe, Ru, and Os atoms can be endohedrally doped in Ta12 to produce electronically closed shell clusters with large highest occupied-LUMO (HOMO-LUMO) gap. Also isoelectronic Co@X12 and Rh@X12 (X = Nb and Ta) cations have a large HOMO-LUMO gap of up to about 1 eV. In these cases the magnetic moment is quenched. On the other hand doping with Ni leaves the magnetic behavior of Ta12 the same. Further anions of Nb15 and Ta15 have a closed electronic shell structure and a singlet ground state with a large HOMO-LUMO gap. We show that isoelectronic Nb14Mo, Nb14W, Ta14Mo, Ta14W, Nb14Mn+, Nb14Re+, Ta14Mn+, and Ta14Re+ all have a large HOMO-LUMO gap of up to about 1.0 eV and are magic clusters. Most interestingly Ta17 has a tetrahedrally sym. Z16 Frank-Kasper polyhedral structure with a large magnetic moment of 5 μB. On the other hand the magnetic moment on Nb17 cluster is 1 μB. The magnetic moment on Ta17 is surprisingly large and it is counter intuitive as normally the magnetic moments decrease as one goes down in a column in the periodic table but some tantalum clusters behave differently. Doping of the n = 17 clusters with Zr at the center leaves Zr@Ta16 magnetic with 2 μB and 6 μB magnetic moments nearly degenerate while Zr@Nb16 has zero magnetic moment.
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The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.chemrev.9b00651.
Comparison between the calculated (PBE0/6-311+G(d)) and experimental bond lengths as well as Raman and infrared frequencies of C60 fullerene (Table S1); comparison between the theoretical (PBE0/PAW) and experimental equilibrium lattice constant, cohesive energy, and bulk modulus of B, C, Si, Ge, Al, Au, Ag, Cu crystals (Table S2). Tables S3–S22 give the geometric and electronic properties of endohedral cage clusters from PBE0/6-311+G(d), SDD calculations for M@C28, M@Bn (n = 18–24), M@Si10, M@Si11, M@Si12, M@Si13, M@Si14, M@Si15, M@Si16, M@Si18, 20, M@Ge10, M@Ge11, M@Ge12, M@Ge13, M@Ge14, M@Ge15, M@Ge16, M@Aun (n = 12–17), M@Agn (n = 8–15), and M@Cun (n = 12, 16). (PDF)
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