Absorption and Fluorescence Spectra of Pr3+ in LaBr3

Abstract

The absorption and fluorescence spectra of 1% and 10% Pr3+ in LaBr3 were observed and an analysis carried out. The energy levels of these Pr3+ ions are very similar to Pr3+ in LaCl3, except that the centers of the J levels differ on the order of 102 cm−1. This corresponds to a change in Slater integrals of 0.5%. This change must be attributed to the different ligands in the two crystals. Two explanations are proposed, one based on a pure ionic model and the other on a model with small covalent bonding.