RESONANT SCATTERING OF PHONONS .I. CN-DOPED ALKALI HALIDES

The resonant scattering of phonons in KCl:CN and KBr:CN has been investigated. It is found that the ω4 dependence for the resonant scattering of phonons as obtained by Griffin and Carruthers for a similar resonance process in n-Ge does not explain published phonon-conductivity results in CN-doped alkali halides in the temperature range where the resonant-scattering dips occur. The results can, however, be described very well by the formula τr-1 ω2(ω2-ω02)2, which has been obtained by Kwok for n-Ge using a Green's-function approach. This approach is well known to be more suitable for frequencies close to the resonant frequencies where the usual perturbation techniques fail because of divergence difficulties. © 1969 The American Physical Society.