THE SPECTRA OF $Sm^{+2}$ IN BARIUM, STRONTIUM, AND CALCIUM HALOFLUORIDES

Author Institution: RCA LaboratoriesDivalent samarium in single crystals of the halofluorides of barium, strontium, and calcium has a number of groups of emission lines in the spectral range $5500 {\AA}-8000 {\AA}$. The transitions, which correspond to $f^{6}, ^{5}D_{j}\longrightarrow f^{6}, ^{7}F_{j1+}$ where $J_{\max} = 3$ and $J^{\prime}_{\max} = 4$, are primarily electric dipole ones. Magnetic dipole transitions are observed in many cases where the symmetry selection rules forbid electric dipole ones. A rather complete spectral assignment has been made with the aid of emission, absorption, and Zeeman spectra. Experimental values of the crystal field parameters for $Sm^{+2}$ in a site of symmetry $C_{4v}=4$ mm have been obtained and a comparison of the crystal field matrix elements of the $^{7}F$ and $^{5}D$ states has been made. The fluorescence lifetimes as a function of temperature provide information about relative values of some of the non-radiative processes