Initial sticking rate of O2 molecular beams on Ni (111) surface depending on kinetic energy

Abstract

Space structures in a low Earth orbit collide with gaseous atoms and molecules with a relative kinetic energy of several electron volts. The action of high speed reactive atoms and molecules accelerates the degradation of material surfaces. In this study, the oxidation states of Ni (111) surfaces that were prepared by irradiation with supersonic O2 molecular beams were analyzed by soft x-ray photoemission spectroscopy with synchrotron radiation. An oxygen uptake curve and an initial sticking rate were remarkably changed depending on the O2 incident energy. An intermediate plateau shown in an oxygen uptake curve disappeared with increasing incident energy due to the change of dissociative adsorption mechanism from a two-dimensional island growth model to a direct activated adsorption model.