Equilibrium geometries, stabilities, and electronic properties of the cationic Au n Be + (n = 1-8) clusters: comparison with pure gold clusters.

Ab initio method based on density functional theory at PW91PW91 level has been applied in studying the geometrical structures, relative stabilities, and electronic properties of small bimetallic Au(n)Be(+) (n = 1-8) cluster cations. The geometrical optimizations indicate that a transition point from preferentially planar (two-dimensional) to three-dimensional (3D) structures occurs at n = 6. The relative stabilities of Au(n)Be(+) clusters for the ground-state structures are analyzed based on the averaged binding energies, fragmentation energies, and second-order difference of energies. The calculated results reveal that the AuBe(+) and Au(5)Be(+) clusters possess higher relative stability for small size Au(n)Be(+) (n = 1-8) clusters. The HOMO-LUMO energy gaps as a function of the cluster size exhibit a pronounced even-odd alternation phenomenon. Sequently, the natural population analysis and polarizability for our systems have been analyzed and compared further.