Concentration Broadening and Oscillator Strengths in Pr:LaCl3

Abstract

The absorption and fluorescence spectra of Pr³⁺ in LaCl₃ have been examined for molar concentrations of 0.26%, 2%, 15%, 50%, 85%, and 100%, and have been used to determine the effect of concentration on the energy levels and transitions of the ion. A model is advanced to explain the concentration broadening of spectral lines in crystals as due to heterogeneity of the lattice and resonance interaction between the spectroscopically active ions. Oscillator strengths were measured for the dilute crystal and the ratio of the strength of the ion‐pair absorption ³P₀+³F₂(μ=2) to that of ³P₀, in PrCl₃, was found to be 1.3×10⁻⁵.