INTRINSIC AND IMPURITY CROSS-LUMINESCENCE IN 3-COMPONENT BARIUM-CONTAINING COMPOUNDS

Time-resolved luminescence excitation spectra under synchrotron radiation (10-30 eV) excitation for the barium-containing compounds BaLn2F8 (Ln = Y, Tm, Yb), (BaF2)1-x -(NdF3)x (x = 0.005-0.3) and SrF2-Ba2+ (0.1-1%) were investigated. It was shown that BaY2F8 crystals have fast cross-luminescence with an excitation threshold at h-nu = 19.3 eV and spectral characteristics similar to that of BaF2. By introducing in BaF2 rare-earth elements with unfilled 4f-shells the long luminescence of self-trapped excitons is suppressed, but fast cross-luminescence is suppressed as well. The existence of impurity cross-luminescence in SrF2-Ba (excitation threshold at about 18.5 eV) was confirmed. Investigations of impurity cross-luminescence give information about the band structure of crystals which do not have intrinsic cross-luminescence.