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

Using O 1s x-ray photoelectron and Mg KL23L23 Auger spectroscopy, we demonstrate that monolayerMgO100/Ag100 exposed at 300 K to H2O vapor pressure of 10−8 Torr is strongly hydrated up to 0.8 H2Oper MgO formula unit, half of the water molecules being dissociatively adsorbed at the fourfold coordinatedsurface oxide sites. These dramatic hydrolysis and molecular adsorption phenomena are strikingly differentfrom those observed at perfect bulklike MgO100 surfaces, and provide strong experimental support to theconcept of unprecedented interactions and properties at oxide-metal interfaces.