The relaxation of Pb2+-vacancy and Cd2+-vacancy dipoles in purified KCl crystals was studied using a double crystal dc polarization method which self-corrects relaxation effects due to spurious causes. In the radius range from Cd2+ to Ba2+ these results and most others support Dreyfus' model. The reciprocal relaxation times for each impurity are given by;.It is also shown that the presence of H2O or its products greatly perturb the relaxation times observed. |