Spectra of Optically Pumped SrF2:Sm2+ and SrCl2:Sm2+

Strong absorption bands from the ${}^5{D}_0{\text{(4f}}^6)$ state were found near 4750, 3170, 2850, and 2470 Å of optically pumped SrF₂:Sm²⁺ crystals and near 4750, 3280, 2740, and 2470 Å of pumped SrCl₂:Sm²⁺ crystals. The decay times of these bands agree with the fluorescence lifetimes of the ${}^5{D}_0{\text{(4f}}^6)$ metastable state in the corresponding crystals at various temperatures. These bands were shown to be transitions from ${}^5{D}_0{\text{(4f}}^6)$ to higher quintet states of the ${\text{4f}}^5\text{5d}$ configuration. The ground‐ and excited‐state absorption spectra of both crystals show a correlation both between themselves and with the free‐ion spectra.