Magneto-Optic Study of the Jahn-Teller Effect in the Excited Level of theF+Centers in CaO

The magnetic circular dichroism was measured in both the zero-phonon line and the broad band of the $F^{+}$ centers in CaO. The spin-orbit coupling constant in the relaxed excited state was found to be -0.58 ${\mathrm{cm}}^{-1\mathrm{}}$. Comparison with the same constant measured in the broad band gives for the Ham reduction factor a value $K\left(T_1\right)=0.02\mathrm{}$. Analysis by the method of moments of the circular dichroism in the broad band allowed the determination of the coupling coefficients of the centers to cubic and noncubic modes of vibration. The values found for these coefficients explain quite well the observed shape of the band.