Effect of Internal Strains on the Paraelectric Resonance ofLi+in KCl

Paraelectric-resonance data for KCl: ${\mathrm{Li}}^{+}$ with a number of crystal orientations at 29.2 GHz are presented. The spectra are in serious disagreement with the predictions of the simple eight-$〈111〉$-dipole model in that two lines appear for certain orientations where only one is expected, and one line appears for other orientations where two are expected. However, these spectra can be explained if internal strains are incorporated into the description.