Thermodynamic and transport properties of the Weeks-Chandler-Andersen fluid: Theory and computer simulation

摘要

The equilibrium molecular dynamics (MD) simulation method is utilized to compute the equation of state, pair correlation function, and transport coefficients of the Weeks-Chandler-Andersen model fluid over a wide range of densities and temperatures. The calculated pair correlation function is used within the virial minimization method to obtain the effective diameter and the results are applied within the generic van der Waals (GvdW) theory to compute the GvdW parameters. The GvdW parameter B, which corresponds to the mean excluded volume of particles, is used to calculate the mean free volume. The computed effective diameter and Gvdw parameters are then fitted to functions of the density and temperature. The modified Cohen-Turnbull theory is employed to calculate the diffusion coefficient using the computed effective diameter and mean free volume. A detailed analysis is presented for the results of the theory and MD simulations for the diffusion coefficient. The system-size dependence of the diffusion coefficient through the MD simulation is studied. The Dullien formula is used to obtain the shear viscosity and the results are compared with those from MD simulations.