A universal formula for the diffusion coefficient of Lennard-Jones fluids

A Hussain and B Akram and XF Yang, MOLECULAR PHYSICS, 123 (2025).

DOI: 10.1080/00268976.2025.2480829

The general law of the self-diffusion coefficient of Lennard-Jones fluids changing with the state parameters of temperature and density is studied. Using the virial theorem, the effect of temperature on the effective diameter of fluid particles is qualitatively explored under the high-temperature approximation, and it is found that the self- diffusion coefficient of the Lennard-Jones fluid system has a 2/3 power scaling relationship with temperature. Molecular dynamics simulation is used to calculate the diffusion coefficient of Lennard-Jones fluids at 437 state points from dense to relatively rarefied. The results confirmed that the diffusion of Lennard-Jones fluids has this simple power dependence on temperature, and then a universal empirical formula for the dependence of the diffusion coefficient on temperature and density was obtained. This formula is believed to be applicable to Lennard-Jones fluids at temperatures above 1.17 and densities other than glass transition.

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