Off-center impurity in alkali halides: reorientation, electric polarization and pairing to F center. III. Numerical calculations

TL;DR

This paper uses numerical calculations to verify analytical results on off-center impurities in alkali halides, focusing on impurity displacement, reorientation, and polarization effects.

Contribution

It provides numerical validation of previous analytical findings on impurity behavior and rotational barriers in alkali halide clusters.

Findings

Off-center displacement of Li+ impurities confirmed

Rotational barrier profiles match analytical predictions

Numerical energies support previous theoretical models

Abstract

We carried out numerical calculations by an extended-Hueckel program in order to check the analytical results reported in the preceding Part I and Part II. We typically consider alkali halide clusters composed of some tens of constituent atoms to calculate electronic energies under static conditions or versus the displacements of particular atoms. Among other things, the off-center displacement of substitutional Li+ impurity in most alkali halides is evidenced. The trigonometric profile of the rotational barriers is also confirmed for KCl.