Quantum-mechanical calculations of defect energies

Abstract

This paper describes the circumstances in which it it necessary to go beyond a semiclassical model in computing the energies of defects in polar solids. The emphasis will be on the ways in which a small cluster, treated quantum-mechanically, can be provided with an environment which represents both the long- and short-range potential of the surrounding crystal. Attention will be given to the additional level of self-consistency which is required between the cluster and its environment. The paper also reviews the application of quantum-chemical methods in generating parameters for the potentials used in semiclassical models.