Orientational correlations in fluids of convex bodies. II. Explicit results for twohyphen; and threehyphen;dimensional systems

摘要

Monte Carlo (MC) simulations and scaled particle theory (SPT) are used to determine a few anisotropic equilibrium properties of an infinitely dilute solution of an ellipse in a bath of circular disks. MC and SPT calculations of orientational polynomials for ellipsehyphen;disk pairs in contact are in qualitative agreement for the systems studied over a range of densities. Quantitative agreement degrades with increasing ellipse eccentricity and at high density. The ellipsehyphen;disk radial distribution function (rdf) has a contact value different than that of a neat fluid of disks at the same density. However, apart from the local surface effect, the full ellipsehyphen;disk rdf is strikingly similar to that of a neat fluid of disks, with the same extrema and a nearly superimposable radial dependence. An SPThyphen;derived rdf for a threehyphen;dimensional fluid comprised of a single ellipsoid in a bath of spheres is used to calculate the density dependence of the meanhyphen;square angular momentum fluctuation in atomndash;(ellipsoidal)diatom collisions. The meanhyphen;square angular momentum fluctuation has a density dependence due primarily to the isotropic collision frequency, with small corrections owing to fluid orientational correlations. The solvent induced shift in the torsional free energy of butane is also determined using SPT.