PECULIARITIES OF EXCITATION OF CE-EMISSION IN CORE REGION OF CHLORINEPEROVSKITES

Excitation spectra of Ce-doped KCaCl3, RbCaCl3, CsSrCl3 and CsCaCl3 cr ystals were studied at 300 and 9 K in the 4-35 eV spectral range using synchrotron radiation. Peculiarities of the excitation spectra in the region of the uppermost core are considered from the view point of fe asibility of the energy transfer from the core excitons and holes to C e-centers. The possible channels for excitation of the activator lumin escence are assumed for the CsCaCl3 and CsSrCl3 crystals exhibiting co re-valence luminescence (CVL) as follows: (i) the reabsorption of the CVL by Ce-centers; (ii) the creation of the valence holes on account o f radiative decay of core excitations via CVL and (iii) the migration of the core holes. All these schemes are distinctly impossible for the CVL-free KCaCl3 and RbCaCl3 crystals where core excitations decay jus t through the non radiative Auger-process. (C) 1998 Elsevier Science L td. All rights reserved.