Electron impact desorption of Xe from the tungsten (110) plane

Abstract

Abstract The electron stimulated desorption of Xe adsorbed on the clean and on oxygen and CO covered tungsten (110) surfaces has been investigated. Only neutral Xe desorption was observed; for Xe on clean W a very small initial regime with cross section 10−17cm2 is followed by a slow decay with cross section 3×10−19cm2. The Xe yield varies nonlinearly with coverage, suggesting desorption from edges of islands or from sites with less than their full complement of nearest neighbor Xe atoms. Desorption from oxygen or CO covered surfaces results in an apparent desorption cross section identical to that of the underlying adsorbate. This results from a kicking off of Xe by electron desorbed O or CO. The true cross sections for these processes are ∼10−14cm2 for Xe-0 and ∼10−15 cm2 for Xe-CO. Some speculations about the mechanism, particularly the absence of ions are presented.