Structural properties and relative stability of silver-doped gold clusters AgAun−1 (n = 3–13): Density functional calculations

Abstract

Density functional calculations using Wu and Cohen generalized gradient approximation functional are performed to investigate the structural properties and relative stability of silver doped gold clusters AgAun−1 (n=3–13). Low-lying energy structures include two dimensional and three dimensional geometries. Especially, for the lowest energy structures, the transition from planar to three dimensional structures is found to occur at n=13 and the impurity Ag atom prefers to occupy higher coordination sites. The calculated binding energies, second-order differences in energies, dissociation energies and HOMO–LUMO energy gaps show pronounced odd–even oscillating behaviors, indicating that clusters with even number of atoms keep a higher relative stability than their neighboring odd-numbered ones. Particularly, the cluster AgAu5 shows the strongest stability. Moreover, vertical ionization potential, vertical electronic affinity, and chemical hardness are discussed and compared in depth. The same odd–even oscillations are found.