Relaxation of Alkali Halide Crystal Lattice by Dipole Defects

Abstract

In /1/ the relaxation energy of the alkali halide lattice with two kinds of dipole defects has been calculated by the lattice static method. They are: 1. dipoles located in one sublattice (divalent impurity with compensating vacancy), 2. dipoles in different sublattices (divacancy). The results of calculations show that the relaxation energy for dipole in one sublattice is higher than for the dipole in different sublattices. To explain this let us consider lattice relaxation with dipole defects. The position of ions is given by R,,, n is the number of elementary cells, v = 1, 2 corresponds to cation and anion sublattices, respectively. Using the lattice static method the ion displacement of ion c, , can be represented as