Correlation between chemical bonding and satellite lines in X-ray photoelectron spectra of transition metal compounds

Abstract

Multielectron processes involved in the core photoionization of 3d-transition metals and metal compounds are considered in connection with the dielectric response to the core-hole creation. Extra-atomic screening is described as a determinant factor limiting the appearance of intense shake-up satellites. This process is achieved by conduction electron polarization in the case of metals or metallic compounds and by bond charge polarization in the case of covalent compounds. Satellite intensity is noticeable when extra-atomic screening is not effecient enough to counteract the perturbing effects of the core-hole potential on the outer orbitals. On the other hand shake-up probability depending on orbital mixing is expected to have a small value of the high ionicity limit. By correlating satellite intensity with the average polarizability and the difference between the electronegativities of anion and cation it is shown that only a limited range of structural and bonding parameters is compatible with the appearance of intense satellites. A discussion of the various possible shake-up transitions is presented.