Anion-radical oxygen centers in small (AgO)n clusters: density   functional theory predictions
  Anion-radical form of the oxygen centers O(-) is predicted at the DFT level for small silver oxide particles having the AgO stoichiometry. Model clusters (AgO)n appear to be ferromagnetic with appreciable spin density at the oxygen centers. In contrast to these clusters, the Ag2O model cluster have no unpaired electrons in the ground state. The increased O/Ag ratio in the oxide particles is proved to be responsible for the spin density at oxygen centers. 
Egor V. Trushin and Igor L. Zilberberg
physics.atm-clus physics.chem-ph