Dependence of the efficiency of various emissions on excitation density inBaF2 crystals

The dependence of the intensity of the emission of self-trapped excitons, c rossluminescence (CL) and intraband luminescence on the excitation density in BaF2 by electron pulses (300 keV, 3 ns) has been studied. The energy inp ut above 2 x 10(19) eV cm(-3) causes quenching of 5.5 eV CL due to the reco mbination of conduction electrons with the outermost-core holes resulting i n the formation of cation excitons and the subsequent energy transfer from a cation exciton to a valence electron of a neighbouring anion. The excitat ion spectra for various fast (tau < 5 ns) and inertial emissions have been measured using synchrotron radiation at 9 K. (C) 2001 Elsevier Science Ltd. All rights reserved.