Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 30: POSTER: Chemical physics

CPP 30.34: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

Stockmayer fluids under the influence of confining disordered materials — •Carsten Spöler and Sabine H.L. Klapp — Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany

The phase behavior of fluids is very sensitive to the nature of the intermolecular interactions as well as to the presence of a confining material on a nanometer scale. Our work bases on integral equation theory (Reference Hypernetted Chain Approximation) in combination with the replica method and we consider Stockmayer fluids (i.e. fluids containing dipolar and Lennard-Jones interactions) exposed to disordered porous matrices (e.g. silica aerogels). The model matrices consist of hard spheres, hard spheres with additional Lennard-Jones matrix-fluid interaction or dipolar hard spheres. For all confined systems a remarkable shift of the boundaries of the homogeneous isotropic high temperature phase, relative to the bulk fluid, is observed as shown on this poster.[1,2] The treatment of the orientational dependence of the dipolar potential is cumbersome but angle-averaged potentials (like the Keesom potential) are known to produce reasonable well predictions of the condensation transition for the bulk Stockmayer fluid (as long as the dipole moment remains relative small). Therefore, we also test the performance of angle-averaged potentials for our confined systems.[3] [1] C. Spöler and S.H.L. Klapp, J. Chem. Phys. 118, 3628 (2003) [2] C. Spöler and S.H.L. Klapp, J. Chem. Phys. 120, 6734 (2004) [3] C. Spöler and S.H.L. Klapp, J. Chem. Phys. 121, 9623 (2004)