Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 12: POSTER Colloids, Nanoparticles and Self-Organizing Systems
CPP 12.4: Poster
Tuesday, March 28, 2006, 17:00–19:00, P3
A fundamental measure free-energy functional for nonspherical particles — •Hendrik Hansen-Goos1,2 and Klaus Mecke3 — 1Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, 70569 Stuttgart — 2ITAP, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart — 3Institut für Theoretische Physik, Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen
In 1989, Y. Rosenfeld established his fundamental measure theory (FMT) free-energy functional for the hard-sphere fluid. The starting point for his derivation is an exact decomposition of the Mayer-f-bond in terms of convolutions of scalar and vectorial weight functions leading him to an excess free-energy function of scalar and vectorial weighted densities. Rosenfeld’s free-energy has proved to describe very accurately inhomogenous hard-sphere fluids and it is conveniently tractable computationally as only one-center convolutions are involved. Later on, a generalisation of his original FMT to nonspherical particles was given by Rosenfeld himself. Unfortunately, the theory does not show an isotropic-nematic transition as observed, e.g., for hard spherocylinders or ellipsoids. Other free-energy functionals that do predict an isotropic-nematic transition generally involve two-center convolutions and therefore demand more computational efforts. Starting from the exact expression for the Mayer-f-bond for convex particles we introduce an approximate decomposition leading us to a new free-energy functional for non-spherical particles. The functional is still based on one-center convolutions and can be shown to yield an isotropic-nematic transition for spherocylinders. Strategies to enhance the agreement with simulation data are presented.