Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: Poster: Colloids and Complex Liquids

CPP 20.16: Poster

Dienstag, 12. März 2013, 18:15–20:15, Poster C

Fundamental mixed measure theory for fluids of hard particles — •René Wittmann and Klaus Mecke — Institut für Theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany

A density functional for anisotropic hard bodies can be constructed in terms of weighted densities which depend on geometry and position of only one single oriented particle [1]. We study the liquid crystalline behavior of a system of hard spherocylinders and compare the results to Monte-Carlo simulations.

The density profile and the director dependence at the isotropic-nematic interface show the correct behavior. The functional also provides closed formulas for the Frank elastic coefficients via the Poniewierski-Stecki equations. The original fundamental measure theory is improved by eliminating the divergence in the free energy of the otherwise unstable smectic phase.

We propose a new geometric method to derive the low-density limit of the exact density functional. Here, so-called mixed measures of two bodies are used rather than weighted densities of only one single particle. This might evade present approximations and lead to an improved density functional for liquid crystals.

[1] H. Hansen-Goos and K. Mecke, Phys. Rev. Lett. 102, 018302 (2009).