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Title: Structural evolution of anionic silicon clusters Si(N) (20 <= n <= 45)

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
OSTI Identifier:
1152417
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory; Journal Volume: 110; Journal Issue: 3
Country of Publication:
United States
Language:
English

Citation Formats

Bai, J, Cui, LF, Wang, JL, Yoo, SH, Li, X, Jellinek, J, Koehler, C, Frauenheim, T, Wang, LS, and Zeng, XC. Structural evolution of anionic silicon clusters Si(N) (20 <= n <= 45). United States: N. p., 2006. Web. doi:10.1021/jp055874s.
Bai, J, Cui, LF, Wang, JL, Yoo, SH, Li, X, Jellinek, J, Koehler, C, Frauenheim, T, Wang, LS, & Zeng, XC. Structural evolution of anionic silicon clusters Si(N) (20 <= n <= 45). United States. doi:10.1021/jp055874s.
Bai, J, Cui, LF, Wang, JL, Yoo, SH, Li, X, Jellinek, J, Koehler, C, Frauenheim, T, Wang, LS, and Zeng, XC. Thu . "Structural evolution of anionic silicon clusters Si(N) (20 <= n <= 45)". United States. doi:10.1021/jp055874s.
@article{osti_1152417,
title = {Structural evolution of anionic silicon clusters Si(N) (20 <= n <= 45)},
author = {Bai, J and Cui, LF and Wang, JL and Yoo, SH and Li, X and Jellinek, J and Koehler, C and Frauenheim, T and Wang, LS and Zeng, XC},
abstractNote = {},
doi = {10.1021/jp055874s},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
number = 3,
volume = 110,
place = {United States},
year = {Thu Jan 26 00:00:00 EST 2006},
month = {Thu Jan 26 00:00:00 EST 2006}
}
  • Results of a combined photoelectron spectroscopy and first-principles density-functional study of SiN - clusters in the size range 20 e N e 45 are reported and discussed. Evidence for a prolate-to-near-spherical shape transition at N 27 is presented. It is shown that the tricapped-trigonal-prism (TTP) structural motif Si9 found in most low-lying clusters SiN -, 9 e N e 19, is replaced or augmented by a series of structural motifs consisting of a bulklike ?adamantane? fragment plus a magic-number cluster (Si6, Si7, Si10) or TTP Si9 in low-lying prolate clusters SiN -, N g 20. For 28 e N emore » 45, almost all low-lying near-spherical clusters SiN -adopt ?stuffed-cage?-like structures where the cages are homologous to carbon fullerenes in the sense that they are composed of only five- and six-membered rings. However the arrangement of the ?stuffing? atoms is not yet diamondlike.« less
  • Photoelectron spectra of anionic clusters of silicon require reliable theoretical calculations for their assignment and interpretation. Electron propagator calculations in the outer valence Green's-function approximation with two well-characterized, all-electron basis sets on vertical electron detachment energies (VEDEs) of anions are compared to similar calculations that employ Stuttgart pseudopotentials. Tests on Si{sub n}{sup -} clusters with n=3-7 exhibit an encouraging agreement between the all-electron and pseudopotentials results and between electron propagator predictions and experiments and values obtained from coupled-cluster calculations. To illustrate the capabilities of the new approach based on a Si pseudopotential and electron propagator methods, VEDE calculations on Si{submore » 10}{sup -} are presented.« less
  • Reactions of silicon atoms and small clusters with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. In addition to the previously reported SiCO monocarbonyl, Si{sub 2}(CO){sub 2} and Si{sub n}CO (n=2-5) carbonyl molecules were formed spontaneously on annealing and were characterized on the basis of isotopic substitution and theoretical calculations. It was found that Si{sub 2}CO, Si{sub 3}CO, and Si{sub 5}CO are bridge-bonded carbonyl compounds, whereas Si{sub 4}CO is a terminal-bonded carbonyl molecule. The Si{sub 2}(CO){sub 2} and Si{sub 3}CO molecules photochemically rearranged to the more stable c-Si{sub 2}({mu}-O)({mu}-CCO) and c-Si{sub 2}({mu}-O) ({mu}-CSi)more » isomers where Si{sub 2} is inserted into the CO triple bond.« less
  • The electronic structure of Snn - clusters _n=4–45_ was examined 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 observed with increasing cluster size. A distinct energy gap was observed in the photoelectron spectra of Snn - clusters with n_41, suggesting the semiconductor nature of small neutral tin clusters. For Snn - clusters with n_42, the photoelectron spectra became continuous and no well-defined energy gap was observed, indicating the onset of metallicmore » behavior for the large Snn clusters. The photoelectron spectra thus revealed a distinct semiconductor-to-metal transition for Snn clusters at n=42.« less
  • We report a systematic and comprehensive investigation of the electronic structures and chemical bonding in a series of ditungsten oxide clusters, W 2O n - and W 2O n (n = 1-6), using anion photoelectron spectroscopy and density functional theory (DFT) calculations. Well-resolved photoelectron spectra were obtained at several photon energies (2.331, 3.496, 4.661, 6.424, and 7.866 eV), and W 5d-based spectral features were clearly observed and distinguished from O 2p-based features. More complicated spectral features were observed for the oxygen-deficient clusters because of the W 5d electrons. With increasing oxygen content in W 2O n -, the photoelectron spectramore » were observed to shift gradually to higher binding energies, accompanied by a decreasing number of W 5d-derived features. A behavior of sequential oxidation as a result of charge transfers from W to O was clearly observed. A large energy gap (2.8 eV) was observed in the spectrum of W 2O 6 -, indicating the high electronic stability of the stoichiometric W 2O 6 molecule. Extensive DFT calculations were carried out to search for the most stable structures of both the anion and neutral clusters. Time-dependent DFT method was used to compute the vertical detachment energies and compare to the experimental data. Finally, molecular orbitals were used to analyze the chemical bonding in the ditungsten oxide clusters and to elucidate their electronic and structural evolution.« less