Adsorption of xenon on oxidized Ni(100) and Ni(111) surfaces by leed and photoemission

Abstract Xenon adsorption has been studied by LEED and photoemission for the systems O Ni(100) and O Ni(111) in a large range of oxygen exposures from the chemisorbed phases to the first stages of oxidation. Xenon adsorption on the ordered oxygen phases evidences the local character of this probe. In the first stages of oxidation, this method confirms the existence of oxide islands even though no diffraction pattern is seen. Two kinds of oxide are clearly distinguished: a surface oxide, dominated by nickel-nickel interactions, and similar to non-stoichiometric oxides, and another oxide with dominant Ni-O interactions whose behaviour more closely resembles bulk oxide.