STRUCTURE OF OXYGEN CENTERS IN LITHIUM FLUORIDE WITH METAL IMPURITIES

Аннотация

The work presents the results of the study of luminescence of LiF-Fe₂O₃, LiF-TiO₂ and LiF-WO₃ crystals during photoexcitation in the region of 4.0...6.2 eV (impurity absorption) at temperatures of 80... 300 K. It was established that in LiF with multivalent metal impurities that replace Li⁺ ions, two types of luminescence centers are created in the form of pairs of O^2--Va⁺ ions located in neighboring nodes and O^2--Me, which correspond to two luminescence bands 3.1 eV and 2.6 eV.

The center O^2--Me (Fe, Ti, W) creates absorption bands in the region 4.0...6.2 eV with parameters similar for the same type of bands in crystals with different metals. The number of these bands is determined by the valence of the metal, that is O^2- the number of ions necessary to compensate for the excess charge of the metal, which are located in the nodes closest to it and form a single complex color center