Observation and description of phonon interactions in molecular dynamics simulations

Three-phonon interactions are identified and analyzed in nonequilibrium molecular dynamics simulations of the Lennard-Jones face-centered cubic crystal. The small simulation cells studied and the classical nature of the simulations lead to a different description of the phonon transport than the quantum-particle model. The selection process is strictly governed by the mode wave vectors. In determining the strength of an allowed interaction, one must consider the mode polarizations and frequencies-the latter in the context of internal resonance. The results are consistent with intrinsic scattering rates calculated directly from the Lennard-Jones potential.