Lifetimes of high-frequency phonons

Abstract

A comparison is made between experimentally and theoretically obtained lifetimes of longitudinal acoustic phonons in ${\mathrm{Al}}_2$ ${\mathrm{O}}_3$, Sr${\mathrm{F}}_2$, Ca${\mathrm{F}}_2$, La${\mathrm{F}}_3$, and $\alpha$-quartz. Theoretical predictions based on an isotropic, dispersionless Debye solid are shown not be be consistent with most of the experimental results.