Parametrization of the electronic structure ofZ+1 impurities

Abstract

The local electronic structure of substitutional Z+1 impurities in metals is calculated self-consistently by means of the Korringa-Kohn-Rostoker Green’s-function formalism, and parametrized in terms of a generalized Clogston-Wolff impurity model. The purpose of this approach is to investigate the core-hole effect, which is encountered in high-energy spectroscopies. The analysis is applied to simple metals as well as transition metals, including the complete 4d row. For the d states a clear renormalization of the impurity-host interaction is observed. We find general agreement between the values of the attractive potentials and the differences in effective levels obtained by first-principles calculations. Within the formalism of the Clogston-Wolff model the trend in the values of the attractive potentials for the 4d states can be explained by a local screening condition and the position of the Fermi level in the band. We comment on the transferability of the model parameters and investigate the screening of a Z+1 impurity in a metal. The effect of a locally overscreened or underscreened core hole is found to be related to the band filling and the character of the Friedel oscillations.