Transport properties of the Lennard-Jones truncated and shifted fluid from non-equilibrium molecular dynamics simulations

Abstract

The thermal conductivity λ, shear viscosity η, and self-diffusion coefficient D of the Lennard-Jones fluid truncated and shifted at the cut-off radius rc=2.5σ (LJTS fluid) are determined for a wide range of liquid and supercritical states (T*=[0.6,10.0] and ρ*=[0.2,1.2]). The simulations are carried out using a non-equilibrium molecular dynamics (NEMD) method that was introduced recently and in which two gradients are applied simultaneously. It is shown that the two-gradient method is well-suited for studies of liquid and supercritical states. Data for λ, η, and D for about 350 state points are reported. Two variants of the simulation method, which differ in the accuracy and efficiency, are explored and found to yield consistent data. Correlations for λ, η, and Dρ of the LJTS fluid are provided. The data and the correlations are compared to literature data of Lennard-Jones (LJ) type fluids and good agreement is observed. The truncation of the LJ potential causes a slight increase in D, while it has no significant effect on λ and η.