Spectroscopy of divalent samarium in alkaline-earth fluorides

One component of the decay of the Sm2+ emission was observed in BaF2 crystals with a lifetime of 16 ms (a slow component) and in CaF2 crystals with a lifetime of 1.3 μs (fast component) at low temperature. In SrF2 crystals, two decay of luminescence components are found in the millisecond and nanosecond time range. The luminescence spectra of the slow and fast components in CaF2, SrF2, BaF2 are similar, which confirms their attribution to forbidden 4f-4f and allowed 5d-4f transitions, respectively. The results obtained made it possible to clarify the position of the excited levels of Sm2+ 4f(5D0) and 5d(eg) relative to the bottom of the conduction band of alkaline-earth fluorides.