Intrinsically Strain-Broadened Line Shapes for Magnetic-Resonance Absorption within a Non-Kramers Doublet

A theoretical model was developed for the line shape of magnetic-resonance absorption for transitions within a non-Kramers doublet (the term doublet is used here to denote the $\left|\Delta M_s\right|=2\mathrm{}$ transition within a ground triplet) for the point-group symmetries $C_{3v}$ and $O_h$. This was done for both the acoustical-paramagnetic-resonance and the electron-paramagnetic-resonance line shapes. The asymmetric broadening of the absorption distribution is interpreted on the basis of the spin-lattice coupling. For the case of $C_{3v}$ symmetry, the calculation was done for both electric-rf-field-induced and magnetic-rf-field-induced transitions, the necessary condition for the former being a lack of inversion symmetry.