Transformation of Radiation-Induced Molecular Point Defects and Color Centers in LiF Crystals under Influence of Light

The influences of UV light and integral light pulses from lamps on gamma-irradiated LiF crystals with impurities of hydroxyl and magnesium ions have been investigated. The optical absorption and luminescence of color centers in different bleaching stages are studied depending on the crystal exposure time under UV light or on the number of light pulses. IR spectra of molecular hydrogen-bonded complexes and hydroxyl ions in different bleaching stages are presented. The transformation of strong hydrogen-bonded complexes under illumination into complexes with weak hydrogen bond (and vice versa) is studied. It is shown how molecular hydrogen-bonded complexes involving hydroxyl affect the transformation of color centers during the crystal bleaching.