Interaction of water vapor with UO2(001)

Mohamed Nejib Hedhili*, B. V. Yakshinskiy, T. E. Madey

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    50 Scopus citations

    Abstract

    We have studied the interaction of water vapor with UO2(001) by using low energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), low energy ion scattering (LEIS) and electron stimulated desorption (ESD). The clean UO2(001) exhibits ordered c(2 × 2) LEED patterns in agreement with previously published data. The X-ray photoelectron spectrum of the U 4f peaks exhibits a clear single satellite at 6.8 eV on the high binding energy side of the U 4f5/2 feature, which has been assigned to a shake-up excitation of an electron from the O 2p-U bonding band to partially occupied or unoccupied localized metal 5f levels. Electron stimulated desorption (ESD) measurements of clean UO2 indicate the desorption of H+ and O+; the O+ desorption threshold is at approx. 25 eV, and the kinetic energy distribution is peaked at 3.5 eV. The O+ desorption threshold is correlated to the ionization of the oxygen 2s level, rather than the U 6p levels. Upon exposure to D2 18O at 300 K, the XPS and ESD results show no evidence of OD formation after water exposure. However, an ESD 18O+ signal appears; both 16O+ and 18O+ signals reach a saturation value after 20 L exposure. Further, LEIS spectra show an 18O peak after water dosage. These results indicate that the water is completely dissociated on UO2(001) and that 18O atoms are incorporated in the surface. The results also suggest a diffusion of oxygen into the bulk.

    Original languageEnglish (US)
    Pages (from-to)512-525
    Number of pages14
    JournalSurface Science
    Volume445
    Issue number2-3
    DOIs
    StatePublished - Jan 20 2000

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films
    • Materials Chemistry

    Fingerprint Dive into the research topics of 'Interaction of water vapor with UO<sub>2</sub>(001)'. Together they form a unique fingerprint.

    Cite this