Modeling the Coupled Mass-Heat Transport in Lennard-Jones-Like Binary Mixtures by Approach-to-Equilibrium Molecular Dynamics

A general theoretical framework to address the coupled heat-mass transport and predict the corresponding Soret and Dufour coefficients is presented. It is shown that by starting from microscopical definitions of heat and mass currents, conservation laws dictate the form of the differential equations governing the time evolution of the temperature and mass density profiles along the sample. The present theoretical device is finally validated using as benchmark system a two-component Lennard-Jones (LJ) liquid system, for which generalized diffusivities are estimated in different reduced temperature and density regions of phase diagram. A comprehensive table of contents capturing the schematic representation of four paradigmatic cases in the investigation of coupled mass-heat transport in LJ-like binary mixtures through approach-to-equilibrium molecular dynamics: a) no gradients; b) temperature gradient only, pure Fourier regime; c) mass density gradient only, pure Fick regime; d) temperature and mass density gradient simultaneously present, coupled regime.image