Density-functional investigation of gold cluster anions doped with gallium: Au n Ga– (1 ⩽ n ⩽ 8)

Abstract

The equilibrium geometric, relative stabilities, electronic and magnetic properties of small AunGa– clusters (1 ⩽ n ⩽ 8), in comparison with pure gold cluster anions are investigated systematically within the framework of the first-principles density functional calculations at the PW91PW91 level. The calculations reveal that the impure gallium atom changes the structure of pure gold clusters. The most stable structures of AunGa– (4 ⩽ n ⩽ 8) prefer three-dimensional structures. The VDE, fragmentation energies and the secondorder difference energies and the HOMO–LUMO gaps for the lowest-energy structures of AunGa– and Au-n+1 (1 ⩽ n ⩽ 8) clusters show an even-odd oscillation along with the cluster size. Meanwhile the above results indicate the doping gallium atom enhance the stability of the clusters. It is must be pointed out that Au2Ga– cluster is the most stable. Finally, we research the natural population analysis (NPA) of Au-n+1 (1 ⩽ n ⩽ 8) clusters. The results indicate that Ga atom attracts electron from the Au atom except for the Au Ga–cluster.