Density functional study of polycarbon sulfides CnS (n = 2−9)

Density functional theory calculations are presented for linear polycarbon sulfides CnS (n = 2−9). Good agreements are obtained between the computed properties of the ground state of these molecules and experimental observations. The BLYP/6–311G∗ or BLYP/6–311 + G∗ methods give stretching frequencies for C3S that are in better agreement than corerlated ab initio methods. Calculated results are also presented for larger clusters CnS (n ⩾ 4), for which only fragmentary information is available. The alternating pattern of the ν1 frequency is related to the variations in the strength of the active bonds with respect to the cluster size.