Optical transitions in pairs of trivalent ion-interstitial fluorine in alkaline-earth fluorides

Absorption, excitation in vacuum ultraviolet region, emission and decay of emission of alkaline-earth crystals (CaF2, SrF2, BaF2) doped by different concentrations of YF3 or LaF3 were studied. New emission bands in the region 3 - 6 eV and excitation bands just below exciton edges were observed. Unempirical Hartree-Fock and density functional calculations of alkaline-earth crystal clusters containing Y or La impurity were performed. We concluded that observed optical bands belong to transitions between interstitial fluorine and trivalent metal parts of pairs Me3+-F-i(-). (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.