PNNL

Abstract

The initial stages of W(110) oxidation have been characterized by surface-sensitive W(4f) core-level photoemission, with the surface-sensitivity provided by the use of tunable synchrotron radiation for excitation. Specific W (4f) photoemission features are assigned to W-atoms bonded to oxygen at coverages below and above 1/2 monolayer(ML). The higher coversge oxygen-induced peaks are at a signigicantly higher binding energy; which is consistent with an increase in the coordination of W to O and, correspondingly, and increase in the extent of charge transfer between W and O.