MANY-BODY CALCULATION OF 3P-XPS AND AUGER-SPECTRA FOR ZN

The Auger electrons and the X-rays emitted in XPS are treated in a unified manner with the photoelectrons as a one-step process, without distinguishing between primary photoionisation and secondary Auger and X-ray emission. Such a formulation will be capable of treating relaxation and interference effects in a consistent and systematic way. The theory is applied to the 3p XPS spectrum of primary and Auger electrons in atomic Zn. Using a diagrammatic RPAE type of treatment for the 3p self-energy and spectral function linewidths of 2.1 eV (3p32/) and 2.2 eV (3p12/) and also super Coster-Kronig (3p to 3d2 epsilon f) and Coster-Kronig (3p to 3d4s epsilon p) spectra are obtained. The authors discuss briefly the problem of screening the localisation-delocalisation of a 3d double vacancy in metallic Zn.