Paramagnetic-Resonance Study of the Dynamic Jahn-Teller Effect in Ca${\mathrm{F}}_2$: ${\mathrm{Sc}}^{2+}$ and Sr${\mathrm{F}}_2$: ${\mathrm{Sc}}^{2+}$

${\mathrm{Sc}}^{2+}$ impurities in Ca${\mathrm{F}}_2$ and Sr${\mathrm{F}}_2$ are studied by electron paramagnetic resonance. The ${\mathrm{Sc}}^{2+}$ has an [Ar] $3d^1$ configuration and undergoes a Jahn-Teller distortion. The vibronic states for the equivalent tetragonal distortions couple to give an inversion splitting of roughly 10 ${\mathrm{cm}}^{-1\mathrm{}}$.