Several isomers of sulfur clusters were acquired by means of geometry optimization and frequency calculations of the B3LYP DFT approach. According to the total energies, the most stable S-n(-) (n = 9similar to13) isomers are of helical configurations. The helical Sn- (n = 14similar to20) structures are also calculated. Most of the anionic clusters are of chain configurations that are completely different from those of the corresponding neutral and cationic clusters in which the ring clusters are in higher total energy
