Density functional for anisotropic fluids

Abstract

We propose a density functional for anisotropic fluids of hard body particles. Itinterpolates between the well established geometrically based Rosenfeld functionalfor hard spheres and the Onsager functional for elongated rods. We test the newapproach by calculating the location of the nematic–isotropic transition insystems of hard spherocylinders and hard ellipsoids. The results are comparedwith existing simulation data. Our functional predicts the location of thetransition much more accurately than the Onsager functional, and almost as wellas the theory by Parsons and Lee. We argue that it might be suited to studyinhomogeneous systems.