Crystal-Field Spectra of the Compensated Lattice: Nonlinear Magnetic Field Dependence and Polarization of TetragonalSm2+Fluorescence in KCl

The field dependence and the polarization of the Zeeman components of 4.2 K fluorescence lines arising from ${\mathrm{Sm}}^{2+}$ ions in tetragonal compensation in KCl have been measured with magnetic fields up to 93.5 kG. The difficulties encountered in the interpretation of crystal-field spectra in lattices distorted by the presence of compensation defects are described. It has been concluded that all the observed narrow lines originate from the ${}_{}{}^5{}_{}{}^{}D_0^{}{}_{}{}^{}$ level, and that most probably the tetragonal lines arise from transitions in the ${\mathrm{Sm}}^{2+}$-${\mathrm{K}}^{+}$ vacancy $C_{4v}(2, 0, 0)$ pair and the ${\mathrm{Sm}}^{2+}$-${\mathrm{O}}^{2-}$ $C_{4v}(1, 0, 0)$ pair. Representation origins of the observed lines have been determined from the polarization data, the field dependence of line intensities, and the previously determined Zeeman anisotropy fluorescence patterns.