CORE-HOLE DECAY STUDIES OF O NI(100) C(2X2)

A study of the core-hole decay spectra of O/Ni(100) c (2 x 2) is prese nted. Spectra were recorded at photon energies corresponding to the O 1s x-ray-absorption (XA) resonance, as well as high above the O is thr eshold. Additional spectra were recorded at photon energies correspond ing to characteristic features in the XA spectrum just above the O 1s threshold. These spectra were found to provide important information r egarding the electronic structure of atomic oxygen on nickel. Broadeni ngs in the decay spectra due to population of Rydberg states are obser ved. A shoulder on the high-kinetic-energy side of the spectra is inte rpreted as a result of Auger final states made up by independent valen ce holes. It was found that the spectroscopic behavior of the O/Ni(100 ) system is in many respects similar to that of pure Ni.