Mechanisms for thermal conduction in methane hydrate.

Crystalline clathrate hydrates exhibit an unusual thermal transport with glasslike thermal conductivity close to the Debye temperature but a crystal-like temperature dependence at low temperature. Molecular dynamics calculations on structure I methane clathrate hydrate reproduced the qualitative trend in the thermal conductivity. Analysis of the heat flux and local energy correlation functions shows that both the crystal structure of the clathrate framework and guest-host interactions contribute to thermal transport processes. The lower thermal conductivity relative to ice Ih is due to differences in crystal structures. The glasslike temperature dependence is governed by the guests and the guest-host interactions.