Infrared spectra and dissociation pathways of the linear carbon-sulfur clusters CnS and SCnS (n <= 29): Theoretical calculations

摘要

Energies, structural parameters, and harmonic vibrational frequencies of the linear carbon-sulfur clusters, CnSm (n = 1-29, m = 1-2), have been computed using density functional theory (DFT) with the B3LYP exchange-correlation functional and Pople's 6-311G* basis set. The energies and equilibrium geometries have been compared to MP2 (Moller-Plesset second-order perturbation) and CCSD(T) calculations for C2S, C6S, and C7S2, three carbon-sulfur clusters recently observed and reported for the first time in the following article. The vibrational frequencies, predicted using B3LYP/6-311G*, agree satisfactorily with the observed infrared (IR) band frequencies, with only a 17 cm(-1) standard deviation for all experimentally known carbon-sulfur cluster C-C stretching modes. Dissociation energies calculated for different loss mechanisms indicate that carbon-sulfur clusters prefer to lose CS, in agreement with experimental observations. (c) 2004 Wiley Periodicals, Inc.