UPS and EELS study of zirconium oxidation

The electronic structure of the zirconium surface with different degrees of oxidation is studied by photoelectron spectroscopy using synchrotron radiation and by electron-energy-loss spectroscopy (EELS). Measurements are performed in one experimental run in the same samples. Some previously unobserved features of the electronic structure have been disclosed. To explain the experimental results, first-principles electronic-structure calculations have been performed for hcp zirconium and for cubic and monoclinic zirconium oxide. The calculated dielectric and loss functions are compared with the EELS data. In spite of small quantitative distinctions, the experimental and calculated results are in qualitative agreement.