Energy Levels of Sm3+ in LaF3

Abstract

The fluorescence and infrared absorption spectra of Sm³⁺ in single crystals of LaF₃ have been observed and analyzed. Fluorescence was observed in the spectral range of 0.55 to 1.1 μm, and absorption in the region of 0.9 to 10 μm. The intermediate coupling free‐ion energy levels of the ⁶FH multiplets have been calculated from energy matrices including the effects of all the quartet and doublet states of the f⁵ configuration. The experimentally determined barycenters of the crystalline Stark components have been fitted to a ``free‐ion'' calculation of the energy levels in terms of the Slater integrals F₂, F₄, F₆, and spin—orbit parameter ζ_4f. A root‐mean‐square deviation of 12 cm⁻¹ was achieved between the calculated and the observed energies. The wavefunctions are tabulated for Sm³⁺ in LaF₃. Values of F₂=356.3 cm⁻¹, F₄=55.77 cm⁻¹, F₆=4.829 cm⁻¹, and ζ=1151 cm⁻¹ are found to give the best over‐all agreement between the observed and the calculated energy levels.