The classical molecular dynamics was used to calculate the fluorine ion mobility in PbMF and PbMKF (M = Ca, Ba) solid solutions with fluorite structure under normal conditions. It was shown that isovalent substitution of lead atoms by calcium atoms in a lead fluoride crystal increases the mobility of fluorine ions, while a similar substitution by barium atoms decreases it. Heterovalent substitution of Pb → K naturally increases the fluorine ion mobility in PbCaKF and PbBaKF solid solutions.
Ji et al. (Wed,) studied this question.