Dielectric Susceptibility of CN- Ions in RbCl from 1 to 26 GHz

The real and imaginary parts of the dielectric susceptibility of the RbCl: CN^- system are measured throughout the 1-26 GHz range. The results, which show a relatively sharp absorption peak at 9.6 GHz and a smaller, broader peak at 4.5 GHz, agree with a model in which the CN^- rotation is both hindered by eight deep potential minima in the [111] directions (XY-8), and severely perturbed by the internal stresses of the crystal (these stresses producing the broad peak at 4.5 GHz). Such an interpretation, in addition to agreeing with the symmetry predictions of previous ultrasonic measurements, can also qualitatively explain the heretofore contradictory results of several other experiments.