Electron reflection spectra of Ce3+ in BeF2 and B2O3 melts

The electron spectra of the melts of BeF₂-CeF₃ and B₂O₃-Ce₂O₃ systems have been obtained via electron reflection spectroscopy in the near UV range. Coordination numbers of cerium(III) ions have been determined in these systems from spectral data. It has been found that the nephelauxetic shift of interconfigurational 4f → 5d electron transitions in cerium ions depends on the degree of covalence of the bonds and the valence of ligands in complex groups, CeF₆ and CeO₆. It has been shown that the character of spectrograms of the B₂O₃-Ce₂O₃ melts depends on the preliminary preparation of the components of the mixture. This is related to the structural heterogeneity of oxide complex groups of cerium(III) ions in borate melts.