Luminescence from Color Centers in KMgF3

A study of the emission from electron- and $\gamma$-irradiated KMg${\mathrm{F}}_3$ crystals reveals bands at 407, 465, 590, 600, and 750 nm. By means of polarized bleaching experiments the bands at 465 and 590 nm can be assigned as due to $F_3$ and $F_2$ centers, respectively. In addition, the temperature dependence of both the widths and peak positions of the emission bands can be used to predict approximate values for the absorption energy of the defects responsible for these bands. The predicted absorption is very close to that observed for $F_2$ and $F_3$ centers. This lends further confidence to the assignments. The 600-nm emission is believed to be due to ${\mathrm{Mn}}^{2+}$ impurity ions.