Deviation from the vavilov law in the short-wavelength band of an f-d transition upon excitation of the luminescence of Tb3+ ions in CaF2 and Tb2(SO4)3 · 8H2O crystals and boron glasses

The study of the excitation spectra of fluorite single crystals and boron glasses activated with Tb(III) in the UV range has shown that, unlike other absorption bands, irradiation at the 215-nm band does not result in luminescence. It has been suggested and experimentally confirmed that the excitation in this band causes ionization yielding tetravalent Tb(IV) ion and, thus, decreasing the luminescence intensity.