Magic silver cluster on a MgO(100) terrace with defects

The structure and energetics of Ag(N) clusters (N=2-10) adsorbed on a double vacancy (DV) neutral defect of a MgO(100) terrace are investigated via a density-functional basin-hopping approach. It is found that Ag(8) is a surface magic cluster from both electronic and structural points of view, i.e., it exhibits enhanced stability with respect to neighboring sizes and a large highest occupied molecular orbital-lowest unoccupied molecular orbital gap. The possibility of synthesizing monodisperse Ag(8)/DV/MgO(100) clusters is discussed. The first ionization potential, the electron affinity, and the interaction energies with atomic and molecular oxygen are evaluated for the adsorbed Ag clusters, showing that Ag(8) exhibits appreciable differences in its electronic and chemical properties with respect to neighboring sizes.