Molecular dynamics study of transport coefficients for hard-chain fluids

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Abstract
Equilibrium molecular dynamics is used to simulate fluids containing molecules modeled as chains of tangent hard spheres. A partially vectorized, efficient algorithm based on the Rapaport method has been designed that allows for very long simulation times and permits calculation of transport coefficients for short chain fluids at liquid-like densities. The self-diffusion coefficient, shear and longitudinal viscosities, and thermal conductivity are calculated for chains of length 2, 4, 8, and 16 at volume fractions ranging from 0.1 to 0.5 using a mean-square displacement approach. Results from the velocity autocorrelation functions provide information about chain motion in the bulk phase. Transport properties for the hard-sphere fluid have also been calculated for systems of 512 particles. Results for chain fluids are compared to results for hard-spheres and to the corresponding Enskog theory.