Relaxation Modes of Trapped Crystal Point Defects: the Three-Neighbor Shells Model in NaCl

Abstract

The results of a relaxation-mode analysis are presented for two cases of trapped-defect relaxation in the NaCl structure, in which both defects occupy the same type of site (e.g., impurity divalent ion and trapped vacancy), or in which they occupy the two different types of sites (vacancy pair). The relaxation analysis is presented in the form of a set of basis vectors in occupation-probability space and a set of secular equations. Solutions to the equations provide the relaxation rates and also the coefficients in the linear combinations of the basis vectors which constitute the relaxation modes.