Structures and electronic properties of Au_n-1Cu and Au_n (n≤9) clusters

A systematic study on the structure and electronic properties of gold clusters doped each with one copper atom has been performed using the density functional theory. The average bond lengths in the Au_n - 1Cu (n \le 9) bimetallic clusters are shorter than those in the corresponding pure gold clusters. The ionization potentials of the bimetallic clusters Au_n-1Cu (n \le 9) are larger than those of the corresponding homoatomic gold clusters except for Au_5. The energy gaps of the Au--Cu binary clusters are narrower than those of the Au_n clusters except AuCu and Au_3Cu. No obvious even--odd effect exists in the variations of the electron affinities and ionization potentials for the Au_n - 1Cu (n \le 9) clusters, which is in contrast to the case of gold clusters Au_n.