Electronic structure of molybdenum oxidized in air

The electronic structure of a clean molybdenum surface oxidized in air and upon sodium Na adsorption at submonolayer coating have been studied by photoelectron spectroscopy in situ in an ultrahigh vacuum. The photoemission spectra from the valence band and O $1s$, O $2s$, Mo $4s$, and Na $2p$ core levels are studied at the synchrotron excitation in the photon energy range 80–600 eV. The spectrum of oxygen core levels related to the substitution of sodium atoms for hydrogen atoms in the hydroxyl group is found to be changed. The surface topography and the cathodoluminescence of the molybdenum oxide has been studied.