Size effect on transport properties of liquid argon: A molecular dynamics simulation study

A series of equilibrium molecular dynamics (EMD) simulations of liquid argon were carried out at 94.4 K and 1.374 g/cc for the calculation of transport properties as a function of the number of argon molecules (N). While the diffusion coefficients (D) of gaseous argon approach the experimental values with increasing N, the viscosities and thermal conductivities obtained for N = 1728 are unreliable due to the high fluctuation of the time correlation functions, but those for N = 13824 are rather acceptable. The EMD results for viscosities overestimate and those for thermal conductivities underestimate the experimental measurements respectively, and it is not expected that further increase in N would give results closer to the experimental measurements. The use of the smaller size LJ parameter could improve the results for viscosities and thermal conductivities of liquid argon at 94.4 K and 1.374 g/cc but not for diffusion coefficients.