Thermally induced diffusion of F2+ color centers in lithium fluoride crystals

The existence of thermally induced diffusion of F2+ centers was shown by measuring the coefficient of optical absorption dichroism of gamma-irradiated LiF crystals. An elementary act of diffusion is a rotation of an F2+ center with the shift of one of the vacancies in the neighbor lattice site, thus, there is a displacement of the center as a whole. The measured activation energy of rotation is 1.0 eV, which is in a good agreement with the energies of​​ the activation process of F2+ centers thermal destruction obtained before.