X-Ray Photoelectron Spectroscopic Study for the Reaction of Evaporated Iron with O2 and H2O

Abstract

Reactions of evaporated iron with O2 and H2O have been investigated by X-ray photoelectron spectroscopy. Binding energies of Fe2p3⁄2 and Ols electrons were measured during the course of reactions and their variation was discussed in terms of the positive and negative charges of the iron and oxygen of the surface oxide formed, respectively, assuming a simple charge-chemical shift relation. They are compared with the binding energies of the Ols in SiO2 Al2O3, Fe2O3, Cd(OH)2, KOH, and Ni(OH)2 and those of Fe2p3⁄2 in various iron compounds High reactivity of the surface oxide with H2O and the resulting hydroxyl group formation were observed. A rough estimation of the Fe to O atomic ratio of the surface oxide was also carried out from the ratio of the Fe and O peak areas.