Paramagnetic Resonance Spectrum of Manganese in Corundum

The paramagnetic resonance spectrum of Mn²⁺ in Al₂{O}₃$ was measured at 3 cm. The spectrum can be expressed in a spin Hamiltonian with trigonal symmetry with the following parameters: ${g}II=2.0017±{}0.001$, ${g}_{{⊥}}=2.000±{}0.002$, $D=+194.2±{}1$, $a{-}F=+21.9±{}0.6$, $A={-}79.6±{}0.5$, $B={-}78.8±{}0.8$ in units of ${10}^{{-}4}$ ${cm}^{{-}1}$.