Absorption and fluorescence spectra of praseodymium in KCl and KBr matrices

Abstract

The observed fluorescence and absorption spectra of single crystals of KCl and KBr doped with praseodymium (Pr) show that the rare earth enters substitutionally as Pr³⁺ in these lattices. However, the site symmetry of the ion has at most a twofold axis. This is shown by the fact that the j-degeneracy of its energy levels is completely removed. Fluorescence is observed to occur only from ³P₀ level to ³F_2,3,4 and ³H₆ levels. The overall stark splitting shows that the Pr³⁺ ion experiences a stronger field in these matrices than in LaCl₃ or LaBr₃.