Title:
THE ENSKOG THEORY FOR SELF-DIFFUSION COEFFICIENTS OF SIMPLE FLUIDS WITH
CONTINUOUS POTENTIALS
Author(s):
K.Miyazaki (IRI, Delft University of Technology, 2629 JB Delft, The
Netherlands; E-mail: K.Miyazaki@iri.tudelft.nl), G.Srinivas, B.Bagchi
(Solid State and Structural Chemistry Unit, Indian Institute of Science,
Bangalore 560 012, India; E-mail: bbagchi@sscu.iisc.ernet.in)
We develop the Enskog theory for the self-diffusion coefficient for fluids with continuous potentials. General expressions for the memory kernel and the self-diffusion coefficient are derived starting from the Green-Kubo formula. The time-dependent memory kernel is calculated and compared with molecular dynamics simulations for the Lennard-Jones fluid. Excellent agreement is obtained at low density. The self-diffusion coefficient is evaluated for several temperatures and densities. The ratio of the Enskog self-diffusion coefficient to the simulation value is plotted against density for the Lennard-Jones fluid. Significant difference of this density dependence from that for the hard-sphere fluid is observed. In particular, the well-known maximum observed in the hard-sphere fluid is found to be completely absent in the Lennard-Jones fluid.
Key words: Enskog theory, self-diffusion coefficient, Lennard-Jones fluid,
memory kernel
PACS: 66.30.H, 47.10.+g
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