Temperature-dependent frequency shifts and broadening of phonon linewidths in lead

A study of the anharmonic lineshifts and linewidths of phonon modes in lead is presented. The interatomic potential is modelled according to a force constant scheme which includes many-body effects both in the harmonic and anharmonic parts. An enhanced damping of the (0.8,0,0) longitudinal mode is predicted and an explanation for this anomalous behaviour is provided. The results are discussed in connection with the available experimental data