Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 3: Liquid Crystals and Polar Fluids
CPP 3.6: Vortrag
Montag, 25. Februar 2008, 11:30–11:45, C 264
A new approach to the quantitative prediction of phase behaviour of quadrupolar fluids — •Bortolo M. Mognetti1, Leonid Yelash1, Peter Virnau1, Wolfgang Paul1, Kurt Binder1, Marcus Mueller2, and Luis G. MacDowell3 — 1Institut für Physik, Johannes Gutenberg–Universität, Staudinger Weg 7, 55099 Mainz, Germany — 2Institut für Theoretische Physik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 3Dpto. de Quimica Fisica, Facultad de Cc. Qumicas, Universidad Complutense, 28040 Madrid, Spain
We investigate the phase behaviour of simple quadrupolar fluid and short alkane in quadrupolar solvents using Grand-Canonical Monte-Carlo simulations. First we carefully investigate Coarse-Grained models for solvents in which molecules are represented by single Lennard-Jones beads plus a quadrupolar moment. We show that these models perform well in predicting equilibria states, also if compared to more realistic (and computationally more expensive) atomistic models. Furthermore we investigate mixtures. Previous investigations have failed to predict the correct type of the binary phase behaviour without modifying the Lorentz-Berthelot mixing rules. We discuss how the new polar coarse grained model for the solvent improves the description of the mixture without any new phenomenological parameter. In order to elucidate the role of quadrupolar interactions we test also the Lorentz-Berthelot rules in some apolar mixtures.