Study with Analytical Equations of Absorption Spectra Containing Interference Dips in Fluoride Glasses Doped with Cr 3+

Abstract : The optical absorption of Cr3+-doped fluoride glasses has been investigated. The lowest energy absorption band 4A2 → 4T2 shows distinct interference dips due to spin–orbit coupling between 4T2, 2E and 2T1 excited states. The dips were analyzed using an analytical method proposed by Bussière et al. ( J. Phys. Chem. A 2003, 107, 1258) based on coupled potential energy surfaces. Then a theoretical crystal-field analysis based on the Racah tensor algebraic method was carried on Cr3+ ions occupying octahedral site symmetry in the fluoride glasses. Satisfactory correlations were obtained between the experimental and calculated energy levels. The fitting of the interference dips also provided a measure of the spin–orbit coupling constant for Cr3+ in fluoride glasses, intermediate between the theoretical value calculated for a fluoride crystal and the value deduced from Racah parameters.