Actively controlled oxidation of Cu{100} with hyperthermal O2 molecular beam

Abstract

The oxidation of Cu{100} with a hyperthermal O2 molecular beam (HOMB) was investigated using x-ray photoemission spectroscopy in conjunction with a synchrotron light source. The efficiency of oxidation with HOMB is higher than that with ambient thermal O2. Further oxidation under oxygen coverage (Θ)⩾0.5 ML occurs rather inefficiently even for the 2.3-eV-HOMB irradiation. We found that such slow oxidation of Cu corresponding to the initial stage of the Cu2O formation can be interpreted in terms of a collision-induced-absorption mechanism. The kinetics of the dissociative adsorption under Θ⩽0.5 ML is well described using the first-order kinetics in a simple Langmuir-type adsorption model.