ELECTRONIC-STRUCTURE AND TRANSITION-PROBABILITIES IN PURE AND CE-3+ DOPED BAF2, AN EXPLORATIVE STUDY

The energy levels responsible for the cross luminescence in BaF2 are well reproduced with the LCAO cluster approach using Gaussian basis sets. Comparative calculations on CaF2 and SrF2 are, even if the estimated bandwidths are considered, in good agreement with band structure calculations reported in the literature. We will explain quantitatively the appearance of two cross luminescence emission components in BaF2 with a decay time of roughly 1 ns. The work on Ce3+ has shown a substantial reduction of the 5d-4f transition rate due to shielding by the 5p shell. This may be partly responsible for the reported small transition rates measured for this ion in various hosts.