Regensburg 2004 – scientific programme

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.54: Poster

Thursday, March 11, 2004, 16:00–18:00, Poster D

The influence of confining disordered materials on the equilibrium behavior of Stockmayer fluids — •Carsten Spöler and Sabine H.L. Klapp — Stranski-Laboratorium für Physikalische und Theoretische Chemie, Sekr. TC 7, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany

The phase behavior of fluids is very sensitive to the nature of intermolecular interactions as well as to the presence of confining material on a nanometer scale. In the present work, which is based on integral equation theory (Reference Hypernetted Chain Approximation) in combination with the replica method we consider dipolar Stockmayer fluids exposed to disordered porous materials. The latter is modeled by a) a hard sphere matrix, b) a hard sphere matrix with additional Lennard-Jones fluid-matrix attraction c) a dipolar hard sphere matrix. As shown on this poster, we find for all systems a remarkable shift of the boundaries of the homogeneous, isotropic high temperature phase relatively to the bulk[1,2]. Our previous studies, however, require a cumbersome treatment of the orientational dependence of the dipolar potential. It is known for bulk Stockmayer fluids that angle-averaged potentials like the Keesom potential lead to remarkable well predictions of the condensation transition (as long as the dipole moment remains relatively small). Here we test the performance of the angle-averaged potential for the confined systems [e.g. model a)], considering particularly the behavior of the isothermal compressibility and adsorption isotherms.

[1] C. Spöler and S.H.L. Klapp, J. Chem. Phys. 118, 3628 (2003)
[2] C. Spöler and S.H.L. Klapp, submitted