X-Ray photoelectron spectroscopy of some uranium oxide phases

Abstract

X-Ray photoelectron spectra of a variety of uranium oxides have been studied and compared with the spectrum obtained from the pure metal. The oxide phases studied were UO_2·0, UO_2·1, UO_2·2, U₄O₉, U₃O₇, U₃O₈, and γ-UO₃ where the formal oxidation number of uranium alters from IV to VI. Significant chemical shifts observed for U 4f and O 1s peaks are explained by consideration of chemical structure and changes in uranium and oxygen oxidation states. The surface oxidation of uranium dioxide powder in air has been studied by comparing the spectra with those of UO₂ pellets and higher uranium oxides.