TY - JOUR

T1 - The formation of new silicon cages

T2 - A semiempirical theoretical investigation

AU - Han, Ju Guang

AU - Ren, Zhao Yu

AU - Sheng, Liu Si

AU - Zhang, Yun Wu

AU - Morales, Jorge A.

AU - Hagelberg, Frank

N1 - Funding Information:
This work is supported by the National Natural Science Foundation of China (20173055), the National Foundation from the Department of Science and Technology of China (970211006), the National Science Foundation (NSF) through the CREST program under the grant HRD-9805465, and the Robert A. Welch Foundation under the grant D-1539. We also express our thanks to Dr J. Hess and D. J. Fox (Gaussian, Inc.), Associate Professor Y. H. Duan (Department of Physics, University of Minnesota) and Dr J. Breidung (MPI at Kohlenforschung, Germany) for their useful discussions.

PY - 2003/5/5

Y1 - 2003/5/5

N2 - A systematic theoretical study on the Sin (n = 26-36, 60) cages using semiempirical methods is herein presented. Equilibrium geometries, harmonic vibrational frequency analyses, enthalpies of formations, HOMO-LUMO energy gaps and other properties are calculated at the level of the AM1 theory. Present theoretical results show that all the Sin (n = 26-36, 60) cage isomers exhibiting maximum symmetry undergo slight distortions into more stable structures of lower symmetry. No simple function for the clusters stability with respect to the number of Si atoms can be discerned in the whole Sin (n = 26-36, 60) series. However, the stability in the Sin (n = 33-36) series decreases as the number of Si atoms drops whereas the Sin (n = 26-32) series shows the same trend with the exception of n = 28 and 31. Several instances of four-fold coordinated, distorted sp3 hybridized Si atoms carrying large net charges have been detected. Calculated HOMO-LUMO energy gaps of these Sin cages lie in the range of 3.9-4.6 eV, being larger than those of both smaller Sin clusters and bulk Si. Comparison with available theoretical and experimental data give firm support to the present application of semiempirical methods to large Sin clusters.

AB - A systematic theoretical study on the Sin (n = 26-36, 60) cages using semiempirical methods is herein presented. Equilibrium geometries, harmonic vibrational frequency analyses, enthalpies of formations, HOMO-LUMO energy gaps and other properties are calculated at the level of the AM1 theory. Present theoretical results show that all the Sin (n = 26-36, 60) cage isomers exhibiting maximum symmetry undergo slight distortions into more stable structures of lower symmetry. No simple function for the clusters stability with respect to the number of Si atoms can be discerned in the whole Sin (n = 26-36, 60) series. However, the stability in the Sin (n = 33-36) series decreases as the number of Si atoms drops whereas the Sin (n = 26-32) series shows the same trend with the exception of n = 28 and 31. Several instances of four-fold coordinated, distorted sp3 hybridized Si atoms carrying large net charges have been detected. Calculated HOMO-LUMO energy gaps of these Sin cages lie in the range of 3.9-4.6 eV, being larger than those of both smaller Sin clusters and bulk Si. Comparison with available theoretical and experimental data give firm support to the present application of semiempirical methods to large Sin clusters.

KW - Geometry structure

KW - HOMO-LUMO gap

KW - Silicon fullerene cages

KW - Stability

UR - http://www.scopus.com/inward/record.url?scp=0038034490&partnerID=8YFLogxK

U2 - 10.1016/S0166-1280(02)00788-1

DO - 10.1016/S0166-1280(02)00788-1

M3 - Article

AN - SCOPUS:0038034490

SN - 0166-1280

VL - 625

SP - 47

EP - 58

JO - Journal of Molecular Structure: THEOCHEM

JF - Journal of Molecular Structure: THEOCHEM

IS - 1-3

ER -