The 4f 6 → 4f 5 5d 1 absorption spectrum of the Sm 2+ ions incorporated in a SrCl 2 single crystal was recorded at 4.2 K in the 15 000-45 000 cm −1 spectral range. The overall spectrum is very satisfactorily simulated by theoretical calculations performed in the frame of the semi-empirical Hamiltonian model. The calculations enabled the assignment of all bands observed in the spectrum as well as a prediction of some experimentally unobserved transitions in the 45 000-55 000 cm −1 region. The rich vibronic structure observed for absorption bands in the 15 000-25 000 cm −1 spectral region is dominated by the vibronic progressions in the totally symmetric Sr-Cl stretching mode of ϳ213 cm −1 upon the thirteen zero phonon lines and local vibration modes at ϳ81 cm −1 and ϳ116 cm −1 . This multiphonon vibronic spectrum is very well reproduced by the model calculation.

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