Anharmonic interaction in aluminum. i

Anharmonic linewidths and frequency shifts have been calculated as a function of temperature for Al, employing an effective interionic interaction derived from a model pseudopotential. Calculations have been carried out along principal symmetry directions at 80 and 300 K and comparison is made with the experimental data of Stedman and Nilsson and with the recent calculations of Högberg and Sandström. The structure of the one-phonon spectral function at 300 K for selected longitudinal phonons is examined in detail and discussed. The presence of a significant asymmetry in the one-phonon peak for the (0.8, 0, 0) longitudinal mode is pointed out. © 1970 The American Physical Society.