Electron Structure and X‐Ray Absorption Spectra of Potassium Chloride I. Band Structure Approach

The conduction band (CB) structure of potassium chloride in a rather wide energy region is calculated by means of the augmented plane wave (APW) method. The important features of CB are the hybridization and interaction of nearly free electron bands with K d‐ and Cl d‐bands. These effects lead to the appearance of many contrast peaks in the energy distribution of the density of K p‐and Cl p‐states. These distributions are compared with the experimental X‐ray K‐spectra in KCl. As a result of this comparison it is concluded that the band theory of an ideal crystal ground state is insufficient for an adequate quantitative explanation of the X‐ray absorption spectra in alkali halides. The assumption is made that one must take in account the deep core hole influence on the final‐states spectrum.