Application of Wertheim's thermodynamic perturbation theory to dipolar hard sphere chains

Abstract

We present results from molecular simulation and statistical mechanics based theory for dipolar hard sphere chains. We consider tangent hard sphere chains with dipoles on alternate segments. The equation of state is obtained by applying Wertheim's associating fluid theory in the total bonding limit to a mixture of non-polar and dipolar hard spheres. The equation of state of the chain requires the compressibility factor and pair correlation functions of this mixture which is the reference fluid. Computer simulation shows that the distribution function between the non-polar and polar hard spheres perpendicular to the dipole can be closely approximated by the hard sphere distribution function. This result is consistent with results from the mean spherical approximation and from reference linear hypernetted chain theory. With this approximation we propose an equation of state for dipolar hard sphere chains.