Model of first-stage F -center production in alkali halides containing divalent cation impurities

A system of equations, describing the formation of F centers and their complements in irradiated alkali halides doped with divalent impurities, has been developed. These incorporate the stabilization of H centers and di-interstitial halogen defects at impurity-vacancy dipoles or aggregates of such dipoles, as well as radiation-induced interstitial detrapping mechanisms. Numerical and approximate analytical solutions of the equations reproduce the dynamic, temperature-dependent features of F-center growth found in experimental studies. They provide a new explanation of the experimentally observed relations between the growth of defects and the divalent-cation-impurity concentration; i.e., the square-root relation between first-stage F centers and such impurities, and the relation between the saturation concentration of HD centers and these impurities.