Thermal transport in gases via homogeneous nonequilibrium molecular dynamics

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Abstract
Thermal transport in gases is investigated by nonequilibrium molecular-dynamics computer simulations. A homogeneous driving force generates a heat flux in the absence of a temperature gradient. It is uniquely derived from a moment-method analysis of the Boltzmann equation by requiring an identical linear response as would result from a temperature gradient. The algorithm is shown to be identical to the Evans-Gillan method if in the latter only kinetic terms are retained in the equations of motion. The validity of this peculiar approach in the linear regime is demonstrated by simulation results for the heat conductivity and the distorted velocity distribution function. In the nonlinear regime, however, the external force leads to an unphysical divergence of the heat conductivity. The accompanying kinetic theory analysis and other recent related work confirm the long-standing presumption that the Evans-Gillan algorithm gives an incorrect nonlinear response.