2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/27158The anharmonic contribution to phonon lifetime and its temperature dependence is calculated from first principle in C, Si and Ge using third-order density-functional perturbation theory. Good agreement with available experimental data is obtained. Different competing two-phonon decay channels are compared and correlated with the density of final states.4 pages, uuencoded, compressed POSTSCRIPT file (debernardi.ps.Z). To extract it, use uudecode and uncompress in turn, SISSA Ref. 116/94/CM/SCCondensed Mattertext