Density functional study of AgnAum and (n + m ⩽ 5) clusters interaction with a single S atom

Atomic sulfur adsorption on small neutral AgnAum and cationic Ag n Au m + clusters (n + m ⩽ 5) has been studied using the PW91PW91 density functional method. The adsorption of S on neutral AgnAum can enhance the stability of the whole cluster. The adiabatic ionization potentials of the cluster sulfides increase as the number of Au atoms increases for the given cluster size. The Natural bond orbital analyses indicate that electron flow in the cluster sulfides is mainly from the s and d orbitals of metal atoms connected to S toward the p orbitals of S. The adsorption energy and dissociation channel of the most stable cluster sulfides were also determined and discussed.