Diffusion of negative ion vacancies in potassium chloride

Abstract

The results of experimental investigations on the rate of relaxation of the enhanced electrical conductivity produced by rapid quenching of potassium chloride are shown to be in good agreement with the theoretical findings of Jain (1958) for the rate of annihilation of lattice vacancies by diffusion to surfaces. The rate of relaxation is found to be independent of the size and shape of specimen, suggesting that the surfaces at which annihilation occurs are those of a submicroscopic structure. The temperature and time dependence of the relaxation together with the theory permit the evaluation of the diffusion coefficient for negative ion vacancies (D₀ ~ 7 cm²s^-1) for potassium chloride, their energy of migration (1·86 eV) and the order of the dimensions of the mosaic blocks (10^-5 cm).