Vibronic transition probabilities in the excitation spectra of the Pr3+ion

Abstract

Vibronic features are observed in the excitation spectrum of Pr³⁺ in several host lattices. Vibronic transition probabilities, A_VIB, for the ³H₄ to ³P₀ excitation transition on Pr³⁺ are reported. A_VIB varies by two orders of magnitude from LaF₃ to Y₂O₂S. These observations are discussed in terms of existing theories of the intensity of vibronic transitions in the intraconfigurational 4fⁿ spectra. The observed variation can be qualitatively accounted for by the differences in covalency, polarizability and opposite-parity configuration admixing.