EPR features of bi component defects in irradiated alkali-haloid crystals

The EPR researches justify a model, according to which the bi component defects are formed on the basis of the Frenkel defects during exposure of alkali-haloid crystals. The first component of defect (F-center) is haloid vacancy with the electron located in its area, second one is negatively charged quasi molecule consisting of two atoms of a haloid. The distance between components predetermines their thermal stability (temperature of annihilation) and EPR parameters. The F-centers are responsible for broad band in EPR spectrum of crystals LiF and NaF, which disappears for registration in a quadrature with the phase of high-frequency modulation of magnetic field. Negatively charged quasimolecules located in the first coordination sphere of F-centers are stabile only for low temperature and annihilate with F-centers even when the temperature increases on some tens degrees. Quasimolecules located farther from F-centers are responsible for STS of EPR spectrum, the distribution of intensity and number of lines in which is characteristic for interaction of a not coupled electron with 14 haloid nucleuses. The intensity of STS lines and broad band are differently changed when the microwave power varies: for first the saturation of absorption is observed which is absent for second. When the doze of gamma-exposure increases the intensity of EPR broad band grows much slower than the intensity of lines STS because F-centers responsible for a broad band are a building material for formation of multi vacancy centers