Hydrolysis at MgO(100)/Ag(100) oxide-metal interfaces studied by O 1s x-ray photoelectron and MgKL(23)L(23) Auger spectroscopy

Using O 1s x-ray photoelectron and Mg KL23L23 Auger spectroscopy, we demonstrate that monolayer MgO(100)/Ag(100) exposed at 300 K to H2O vapor pressure of 10(-8) Torr is strongly hydrated up to 0.8 H2O per MgO formula unit, half of the water molecules being dissociatively adsorbed at the fourfold coordinated surface oxide sites. These dramatic hydrolysis and molecular adsorption phenomena are strikingly different from those observed at perfect bulklike MgO(100) surfaces, and provide strong experimental support to the concept of unprecedented interactions and properties at oxide-metal interfaces.