Phonon Conductivity of CdTe:Fe+2and MgO:Fe+2

A phenomenological form for $\omega$ dependence of ${\tau }_r^{-1\mathrm{}}$ is proposed which takes into account a term known as the population-difference factor. The thermal-conductivity-vs-temperature curves for CdTe: ${\mathrm{Fe}}^{+2\mathrm{}}$ and MgO: ${\mathrm{Fe}}^{+2\mathrm{}}$ are explained satisfactorily except that there are slight deviations at the low-temperature as well as at the high-temperature side.