Theory of Positron Annihilation in Sodium, Aluminum and Argon.

Abstract

<p> This work is concerned with the calculation of the angular correlation curves and the lifetime of positrons annihilating in Sodium, Aluminum and Argon. The Carbotte-Kahana theory is developed using orthogonalized plane waves to represent conduction states. The theory is put in a computational form and techniques, which reduce the computational labour to a manageable level are developed for its practical evaluation. Results are obtained for the electron core contribution in Sodium and Aluminum whilst for Sodium a lattice contribution is also attempced. The core theory is applied to Argon with a limiting approximation and results are obtained in a first order perturbation theory approximation. The calculations are compared to experiment with a satisfactory result. </p>