Vibronic spectra of Eu3+ in lanthanide oxysulfides and oxyhalides

Abstract

Vibronic luminescence spectra and vibronic luminescence-excitation spectra with laser excitation were considered in this work. At low temperatures the luminescence spectra of Eu/sup 3 +/ and Tb/sup 3 +/ in oxysulfides and oxyhalides contain hundreds of lines. The vibronic side bands of the electronic transitions are isolated with the aid of the temperature dependence of the intensity of the lines. The vibronic excitation spectra were also considered, making it possible to get rid of some of the superpositions and to obtain the single-phonon bands in a ''purer'' form and at lower temperatures. The temperature dependence of the intensities of lines has been used to identify the vibronic bands in the luminescence spectra of Eu/sup 3 +/ and Tb/sup 3 +/ in lanthanide oxysulfides and of Eu/sup 3 +/ in these compounds have been obtained. A comparison of the vibronic spectra with the IR and Raman spectra has been carried out, and the width of the phonon bands has been evaluated. Graphs and tables are included.