Configuration Shifts in Narrow Bands due to Coupling with a Broad Conduction Band

Abstract

As an application of a thermodynamic perturbation theory¹, I have studied the effects of couplings between many electron configurations on atoms in metals and broad conduction electron bands. Of particular interest has been those situations in which many electron states with different numbers of electrons participate in relatively strong fluctuations. One of the main characteristics of this study is the attempt to avoid the one-electron picture implicit in the usual HF approach and deal with the many-electron configurations in a fashion that allows, at least in principle, the treatment of atomic correlation effects in zeroth order. The simplest conceptualization of our results is obtained in the S-shell Anderson model² of a single impurity atom in contact with a host conduction electron band. Extensions of these considerations to compounds like CeAl₃ with very narrow f-shell bands will be discussed at the end of this paper.