A systematic analysis of the spectra of the lanthanides doped into single crystal LaF3

Abstract

The optical spectra of the lanthanides doped into single crystal LaF₃ have been interpreted in terms of transitions within 4f ^N configurations. Energy matrices combining free‐ion terms with a crystal field for an approximate model which assumes C_2v instead of the actual C₂ site symmetry were diagonalized. Excellent correlations were obtained between experimental transition energies and the computed level structures. We also report the results of previously unpublished experimental spectroscopic investigations of Nd³⁺ and Sm³⁺:LaF₃, as well as predicted energy levels for Pm³⁺:LaF₃. The spectroscopic data for each ion were independently interpreted using an effective‐operator model, then the model parameters were intercompared. Systematic trends have been identified, and a comprehensive energy level diagram is presented.