Structural and Electronic Properties of Stable Au_nIr₂ (n = 1 – 7) Clusters: Comparison with Pure Gold Clusters

Abstract

The geometrical structures, relative stabilities, electronic and magnetic properties of Au n Ir 2 (n = 1 -7) clusters have been systematically investigated by using meta-generalized gradient approximation (meta-GGA) Tao-Perdew-Staroverov-Scuseria (TPSS) functional in comparison with pure gold clusters. The optimized geometries show that the two doping iridium atoms can affect the structure of the host cluster. Compared with the pure Au n+2 clusters, the lowest energy Au n Ir 2 (n = 1 -7) clusters favour higher spin multiplicity except for Au 7 Ir 2 . Furthermore, the calculated binding energies, fragmentation energies, second-order difference energies, and the highest occupied-lowest unoccupied energy gaps indicate that the stability of Au n Ir 2 is enhanced. Natural population analysis reveals that the charges transfer from the Au n frames to the iridium atoms for Au 3,4,6,7 Ir 2 clusters. In addition, charges and magnetic moments of 6s, 5d, and 6p states for the iridium atoms in Au n Ir 2 (n = 1 -7) clusters are also analyzed and compared.