Oxygen on an approximately W(110) single crystal: electron reflection, electron energy-loss spectroscopy, and work-function measurements

Abstract

Adsorption of oxygen on W(110) at room temperature has been studied by means of electron reflection, high-resolution electron energy-loss spectroscopy, and work-function measurements. Data collected with these different techniques show that a change in the structure of the adlayer takes place at a coverage of about a 0.2 monolayer. In the low-coverage state, sharp low-energy electron diffraction fine structures in the reflected current, a slow variation in the work-function variation, and a single vibration loss at 68 meV are observed. At higher coverage, a damping of the fine-structure features, a normal work-function increase, and a shift of the 68 meV loss peak to 73 meV together with the growth of a 48 meV loss are observed. These observations seem to support models involving initial dissociation near surface defects and subsequent p(2 × 1) island growth).