A systematic search for the structures, stabilities, and electronic properties of bimetallic Ca _2-doped gold clusters: Comparison with pure gold clusters

摘要

The local meta-GGA exchange correlation density functional (TPSS) with a relativistic effective core potential was employed to systematically investigate the geometric structures, stabilities, and electronic properties of bimetallic Ca _2Au _n (n=1-9) and pure gold Au _n (n≤11) clusters. The optimized geometries show that the most stable isomers for Ca _2Au _n clusters have 3D structure when n>2, and that one Au atom capping the Ca _2Au _(n-1) structure for different-sized Ca _2Au _n (n=1-9) clusters is the dominant growth pattern. The average atomic binding energies and second-order difference in energies show that the Ca _2Au _4 isomer is the most stable among the Ca _2Au _n clusters. The same pronounced even-odd alternations are found in the HOMO-LUMO gaps, VIPs, and hardnesses. The polarizabilities of the Ca _2Au _n clusters show an obvious local minimum at n=4. Moreover, the inverse corrections to the polarizabilities versus the ionization potential and hardness were found for the gold clusters.