Molecular dynamics simulations of self-diffusion coefficients in binary isotopic Lennard-Jones solutions

Publisher Website
Google Scholar
Abstract
Molecular dynamics simulations of self-diffusion coefficients in binary solutions of isotopes have been carried out for mole fractions 0·2, 0·5, and 0·8 at constant density and temperature, over a wide range of molecular mass ratios, with Lennard-Jones potential parameters corresponding to argon. A symmetry relation is demonstrated which provides results for two mass ratios from a single calculation. The data are fitted to empirical equations and extrapolated to infinite dilution to give tracer diffusion coefficients. It is found that the calculations are in agreement with experimental data on the diffusion of benzene isotopes in a variety of hydrocarbon solvents. The relationship of the results to perturbation theory is considered briefly, and a prediction is verified numerically. The paper concludes with a general discussion of the effects of the medium on the diffusion coefficient ratios.