Inverse photoemission study of the early stages of polycrystalline iron oxidation

Abstract

We present an inverse photoemission (IP) study of polycrystalline Fe oxidation performed at room temperature in the exposure range from 1 to 103 langmuir (1L = 10−6 Torr · s). The spectra have been taken in the isochromat mode in the intraviolet photon energy range from 10.5 to Ev. In this region the empty 3d states give rise to a sharp and well defined feature which moves away from the Fermi level on going from the clean metal to the oxidized system. This effect saturates at an exposure of about 5 L. The data are compared with recent IP results from the complete family of Fe bulk oxides.