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Core electron energy loss spectroscopy of cerium: Surface oxidation

1984; American Institute of Physics; Volume: 2; Issue: 2 Linguagem: Inglês

10.1116/1.572516

1520-8559

Gregor Strasser, H. Netzer,

Electron and X-Ray Spectroscopy Techniques

Core electron excitations of clean Ce and of Ce exposed to varying amounts of oxygen and H2O have been studied by electron energy loss spectroscopy (ELS) in reflection geometry. The valence change of Ce atoms during surface oxidation with oxygen is well reflected in ELS of core levels. 4d→4f excitations provide the best spectral fingerprint of the valence state, but 3d→4f and 4p→5d excitations also show spectral modifications which can be correlated to the change in f count. The spectral profiles of core level excitations of a CeO2-like oxide phase are discussed in terms of screening effects on the core hole–excited electron final states.