Evolution of structures, stabilities, and electronic properties of anionic [AunRb]− (n = 1–10) clusters: comparison with pure gold clusters

Abstract

The geometric structures, stabilities, and electronic properties of small size anionic [AunRb]− and Aun+1− (n = 1–10) clusters have been systematically investigated by using density functional theory. The optimised geometries show that the structures of [AunRb]− clusters favour the three-dimensional structure at n ≥ 8. The Rb atoms tend to occupy the most highly coordinated position and form the largest probable number of bonds with gold atoms. One Au atom capped on [Aun-1Rb]− structures is the dominant growth pattern for n = 2–8 and Rb atom capped on Aun− structures for n = 9–10. The averaged atomic bonding energies, fragmentation energies, second-order difference of energies, and highest occupied molecular orbital–lowest unoccupied molecular orbital gaps exhibit a pronounced even–odd alternations phenomenon. The charges in [AunRb]− clusters transfer from the Rb atoms to Aun host. In addition, it is found that the most favourable dissociation channel of the [AunRb]− clusters is to eject a Rb atom and the highest energy dissociation path is Rb− anion ejection.