Structure and bonding in mixed silicon-carbon clusters and their anions

Density functional calculations with simulated annealing have been performed for singly charged mixed silicon-carbon cluster anions SinCm- and for neutral SinCm clusters with up to eight atoms. The calculations predict the existence of a number of previously unknown isomers and identify two classes of anion structure: carbon-rich (chainlike) and silicon-rich (three-dimensional), with pronounced differences in the vertical detachment energies (VDE, transitions to states of the neutral clusters). The results provide insight into recent photoelectron detachment measurements on the anions. (C) 1996 American Institute of Physics.