Size-selective effects in the geometry and electronic property of bimetallic Au–Ge nanoclusters

We systematically investigated the size-selective effects of geometrical structures and electronic properties on anionic AuGe n - (n = 1–13) nanoclusters by using density functional theory (DFT-B3LYP) calculations with double-ξ LanL2DZ basis set. The lowest-energy structures and their low-lying isomers were identified. Compared with the neutral clusters, the ground state structures of AuGe 8 - and AuGe 9 - were obviously rearranged due to the addition of an extra electron. The threshold number of endohedral cage-like AuGe n - clusters was favored at n = 10, whereas the most stable cluster was found at n = 12, and reflected by the average binding energies and second-order difference in the total energies. The present results demonstrated that the induced effects by an additional electron to the neutral clusters can enhance their stabilities. However, the values of HOMO–LUMO gaps have a decreasing tendency along with the increasing number of Ge atoms. Adiabatic electron affinity (AEA), vertical electron affinity (VEA), and vertical detachment energy (VDE) were obtained and discussed in detail. The chemical bondings of some stable nanoclusters were also analyzed with the electron localization function (ELF).