ABSTRACT
In the previous chapter we described a computational model for point defects in insulators. In it, the local region containing the defect is to be analysed quantum-mechanically, and the rest of the crystal is to be described in terms of a classical atomistic model. In the applications described in Chapter 11, all atomic positions and configurations were assumed to be static. The quantum-mechanical part of the model consists of the electrons associated with a small molecular cluster containing the point defect, including the interaction of the electrons with nuclei in the cluster and with the classical atoms of the embedding region. This chapter is devoted to the theoretical background of such a quantum-mechanical calculation.
