Comments on Klein's Theory of the Thermal Conductivity of Doped Alkali Halides

Abstract

Klein's theory of the resonant phonon scattering from a two-level tunneling system has been applied to the KCl: ${\mathrm{CN}}^{\ensuremath{-}}$ system. Unlike the KCl: ${\mathrm{OH}}^{\ensuremath{-}}$ and NaCl: ${\mathrm{OH}}^{\ensuremath{-}}$ systems, agreement between theory and experiment is achieved with $n=1$. It is concluded that the scattering due to the mass defect ($n=2$) and the scattering due to force-constant changes ($n=4$) do not play a significant role in causing the resonance dips in the $K$-vs-$T$ curves in KCl: ${\mathrm{CN}}^{\ensuremath{-}}$ systems.