Theoretical study of the Ge m Si n (m + n = 3) clusters

• Published in: International journal of quantum chemistry Vol. 111; no. 7-8; pp. 1562 - 1569
• Main Authors: Ueno, Leonardo T., Kiohara, Valéria O., Ferrão, Luiz F. A., Marim, Luiz R., Roberto‐Neto, Orlando, Machado, Francisco B. C.
• Format: Journal Article
• Language: English
• Published: 01.06.2011
• ISSN: 0020-7608; 1097-461X
• DOI: 10.1002/qua.22747

Abstract The main objective of this study consists in providing reliable structures, harmonic vibrational frequencies, and relative electronic energies of Si 3 , GeSi 2 , Ge 2 Si, and Ge 3 clusters using DFT, CCSD(T), CASSCF, and MP2 methods and extended basis sets. The CCSD(T) results are extrapolation to the complete basis set (CBS) limit. For Si 3 cluster, the ground‐state is a singlet ( 1 A 1 ) and the lowest lying electronic state is triplet state ( $ ^{3}{\rm A}^{\prime}_{2}$ ) separated by 0.44 kcal mol −1 at the CCSD(T)/(CBS) limit. The ground‐states of GeSi 2 , Ge 2 Si, and Ge 3 clusters are also singlet state with triplet states very close energetically. Computed equilibrium geometries and vibrational frequencies are compared with previous theoretical and experimental data. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010