A systematic search for the structures, stabilities, and electronic properties of bimetallic Ca₂-doped gold clusters: comparison with pure gold clusters.

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(2)Au( n ) (n = 1-9) and pure gold Au( n ) (n ≤ 11) clusters. The optimized geometries show that the most stable isomers for Ca(2)Au( n ) clusters have 3D structure when n > 2, and that one Au atom capping the Ca(2)Au( n-1) structure for different-sized Ca(2)Au( 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(2)Au(4) isomer is the most stable among the Ca(2)Au( n ) clusters. The same pronounced even-odd alternations are found in the HOMO-LUMO gaps, VIPs, and hardnesses. The polarizabilities of the Ca(2)Au( 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.