Phonons have finite lifetimes 𝜏 ?@ due to a variety of scattering processes, which means that the intrinsic linewidths Γ ?@ = ℏ 𝜏 ?@ ⁄ (where Γ ?@ is the Lorentzian FWHM linewidth) vary as a function of energy and wavevector, and are intrinsically temperature-dependent through the populations of the modes involved in the scattering processes. We have previously treated phonon linewidths as an empirical parameter, while Lunghi et al. proposed a simplified model for an effective phonon linewidth based on the NVT canonical ensemble (Equation ). Γ ?@ = 2ℏ𝜔 ?@ expBℏ𝜔 ?@ 2k D 𝑇 ⁄ E expBℏ𝜔 ?@ k D 𝑇 ⁄ E -1