Resonance phonon scattering on stable F 2 + centers in LiF crystals irradiated in the stressed state

The joint action of gamma irradiation and mechanical stress on the optical absorption spectra and thermal conductivity of LiF crystals has been investigated both theoretically and experimentally. Optimum irradiation doses and stress magnitudes for the stabilization and the efficient accumulation of F₂⁺ centers in LiF are determined. The intensity of the absorption band due to F₂⁺ centers is reduced by less than a factor of two in measurements a year apart. The expression for the cross section of resonance phonon scattering on F₂⁺ centers is obtained, and the parameters of the model of the center are determined. The temperature dependence of the thermal conductivity is calculated, and a bend in the (T) curve revealed atT3–5 K is explained.