The insertion of O atoms into Ag and their interaction with vacancies were studied by means of density-functional theory calculations, using a plane wave basis set. The O atoms were found to be preferentially inserted into octahedral interstitial sites and to exhibit strong interactions with monovacancies as well as with divacancies. A novel configuration was found for the O-divacancy complex, in which the O atom was located halfway between the 2 nearest-neighbor vacancies, whereas the O-vacancy pair reduced in effect to an O atom in the available substitution site. Quantitative estimates of the formation energies of Ag mono- and divacancies, solution energies of O in various sites, and the binding energies of O with 1 or 2 vacancies were calculated using either local density or generalized gradient approximations. Both functionals led to the same qualitative results, but the calculated energies differed significantly. It was not possible to conclude, by comparison with available data, which functional was the more accurate.

Oxygen and Vacancies in Silver - a Density-Functional Study in the Local Density and Generalized Gradient Approximations. J.P.Crocombette, H.De Monestrol, F.Willaime: Physical Review B, 2002, 66[2], 024114 (5pp)