Use of the absolute Auger parameter for vanadium in the study of the dielectric relaxation of cerium vanadate

X-ray photoelectron spectroscopy (XPS) is known, mainly, as a technique for surface analysis. It is especially valued for interpretation of the chemical state by means of the chemical shift. This paper concerns the contribution to this shift from polarization of the ligands following core photoionization. Intercalation of ions such as lithium will influence the electronic polarizability of the oxygen ions and hence the value of the Auger parameter (AP). The AP is the difference in kinetic energy of the Auger peak in the spectrum and that of the principal photoelectron peak, calculated by an internationally accepted procedure. Thus, while obtaining the composition and chemical state of a compound one can also determine the polarizability of the material. Polarizability is crucial to the dielectric properties of oxides, such as refractive index, and is of value in optimizing intercalation compounds for use in optoelectronic devices. The use of this methodology will be illustrated using the vanadium ion in V2O5 and CeVO4, including its lithium-intercalated form. Copyright (C) 2002 John Wiley Sons, Ltd.