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The impact of dispersion relations, anisotropy, and Brillouin zone structureon intrinsic phonon scattering rates has been assessed within the harmonicapproximation-perturbation theory approach for lattice dynamics. Anisotropicnonlinear elastic continuum has been considered with various levels ofrepresentation of phonon dispersion and Brillouin zone shape, and withGr\"uneisen parameter used as an average measure of crystal anharmonicity. Inaddition, thermal conductivity prediction of different models for the treatmentof the off-diagonal elements of phonon collision operator are compared. For amodel system, argon, with a relatively high anisotropy ratio, the results showthat accounting for anisotropy is critical for accurate determination ofavailable phase space for 3-phonon scattering and scattering rates. Moreover,widely spread approximations such as isotropic continuum and Single ModeRelaxation Time are found unreliable, even for cubic systems. The success ofthese approximations is demonstrated to be a direct result of errorcancellations. By benchmarking against our iterative solution of BoltzmannTransport Equation, which achieves excellent agreement with experimentalthermal conductivity data for solid argon (2-80 K), we show the essentialimportance of considering coupling terms of phonon scattering kernel at phononmode level, and not in a statistical average sense as, for example, Callawaymodel does. Moreover, our results manifest the role played by coherent phononscattering near the melting temperature, in agreement with molecular dynamicsfindings, which serves as an evidence for the crossover between heat diffusionmediated by particle-like phonons (incoherent scattering) and wave-like heatpropagation due to phonon coherent scattering. Furthermore, sensitivity ofconductivity prediction to phonon spectrum is revealed to change overtemperature.

Quantitative assessment of perturbation theory-based lattice thermal conductivity models using quasi-continuum approximation