An equation of state for the hard-sphere chain fluid: theory and Monte Carlo simulation

We have developed a modified version of the thermodynamic perturbation theory of Wertheim for the hard-sphere chain fluid by incorporating structural information for the diatomic fluid. Using two explicit expressions for the site-site correlation function at contact for the diatomic fluid, we obtained new equations of state for the hard-sphere chain fluid which are accurate at both low and high densities. We also performed Monte Carlo simulations for a bulk hard-sphere chain fluid, and obtained the compressibility factor using the Nezbeda's pressure equation extended to a chain fluid. We found that our results are consistent with the results of Dickman and Hall, but of higher accuracy and cover a wider range of density. By comparing with simulation results, we find that our modified thermodynamic perturbation theory is an accurate and convenient tool which can be useful for more realistic models of chain fluids.