Electron-positron correlations in jellium within the self-consistent Kahana approach

Abstract

The role of the electron-positron enhancement factor epsilon (p) in investigations of the electronic structure of metallic materials by positron annihilation is emphasised. A calculation of this function, performed according to a self-consistent extension of the Kahana formalism, is presented. The merits of this approach in comparison with the traditional approach comprise inclusion of the effect of electron-electron correlations and the achievement of full self-consistency between the potential assumed in the Bethe-Goldstone equation and the screening charge distribution around a positron, obtained from its solutions. In this way the low-density divergence of the annihilation rate lambda is removed-in this region it approaches the averaged free-positronium value. The annihilation parameters obtained in this work are in reasonable agreement with experimental results.