The semi-empirical method, and 224-atom quantum clusters, were used to calculate the activation energies for the diffusion of cation and anion vacancies and F-centers in crystals. The predicted activation energies of 1.19, 1.44 and 1.64eV, respectively, agreed well with experimental data.

M.M.Kukija, E.A.Kotomin, A.I.Popov: Journal of the Physics and Chemistry of Solids, 1997, 58[1], 103-6