Electronic structure and chemical reactivity of oxide-metal interfaces: MgO(100)/Ag(100)

We present an electron spectroscopy investigation of the MgO(100)/Ag(100) oxide-metal interface electronic structure. We find that the O 2p states strongly hybridize with the Ag 5sp band and only weakly with the Ag 4d band. As a result of these interactions, a substantial density of states with a large oxygen antibonding character is pushed above the Fermi level, determining the chemical bonding at the oxide-metal interface. One striking consequence of such an electronic structure is the strong chemical activity of the interface toward H2O dissociative chemisorption.