Fluorescent Spectra ofSm2+in KCl. III. Site-Symmetry Correlation of Lines by Crystal Comparison and the Thermal Dependence of Intensities and Lifetimes

In this final paper in the series on the fluorescent spectra of ${\mathrm{Sm}}^{2+}$ in KCl, the authors present results of studies on the spectra of two different crystals at different temperatures, together with detailed studies in one crystal of the intensity and lifetime behavior versus temperature. Three sets of lines are found corresponding to three different site symmetries for the ${\mathrm{Sm}}^{2+}$-${\mathrm{K}}^{+}$-vacancy system. All the prominent lines belong to the same set showing that they originate from the same level of the same (site-symmetry) ion. Magnetic studies presented in Papers I and II show that this site symmetry is $C_{2v}$, in accord with the earlier work of Bron and Heller.