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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 (Møller–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. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [ABSTRACT FROM AUTHOR]

Carbon–sulfur clusters have been generated by the laser ablation of mixed sulfur–graphite pellets and the pulsed‐jet discharge of acetylene/carbon disulfide/argon or diacetylene/carbon disulfide/argon mixtures. Fourier transform infrared absorption spectroscopic measurements of cryogenic argon matrices, aided by Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar (B3LYP/6‐311G*) calculations of the previous paper, has led to the identification of six heretofore unknown CnSm clusters: C6S, C7S2, C9S2, C11S2, C13S2, and C15S2. In addition, C2S has also been formed and bands at 1662.6 and 857.2 cm−1 unambiguously assigned to its C–C and C–S stretching modes, respectively. Using 12C/13C isotopic substitution and density functional theory calculations, bands at 1377.9, 1368.8, 1832.4, and 1796.9 cm−1 have been assigned to the ν4, ν7, ν10, and ν12 C–C stretching vibrations in linear C6S, C7S2, C13S2, and C15S2 clusters, respectively. From intensity correlation measurements, the 2056.7, 1938.2, and 1504.5 cm−1 bands have been attributed to the C7S2 (ν5, ν6), and C15S2 (ν13) clusters, respectively. A “coincidence plot” has been used to ascribe several additional bands to the C9S2 (ν7, ν8), and C11S2 (ν9) clusters. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [ABSTRACT FROM AUTHOR]