Abstract:
The work presents the results of the study of luminescence of LiF–Fe$_2$O$_3$, LiF–TiO$_2$ and LiF–WO$_3$ crystals during photoexcitation in the region of 4.0$\dots$6.2 eV (impurity absorption) at temperatures of 80$\dots$300 K. It was established that in LiF with multivalent metal impurities that replace Li$^+$ + ions, two types of luminescence centers are created in the form of pairs of O$^{2-}$–$V_a^+$ 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$\dots$6.2 eV with parameters similar for the same type of bands in crystals with different metals. The number of these bands is determined by the valence of the metal, that is O$^{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.
Keywords:photoluminescence, lithium fluoride, metal impurities, oxygen centers.
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