Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster Session 2
CPP 37.62: Poster
Mittwoch, 2. April 2014, 15:00–19:00, P3
Monte-Carlo Simulations on the CH4/CF4 mixture — Joyjit Chattoraj1, Tobias Risthaus2, •Oliver Rubner1, Stefan Grimme2, and Andreas Heuer1 — 1Institute of Physical Chemistry, University of Münster, Germany — 2Institute of Physical and Theoretical Chemistry, University of Bonn, Germany
It is known, though not understood at all, that methane and perfluoromethane are immiscible below 95K and behave thus similar to other mixtures of hydrocarbons and perfluorinated molecules. In this work we want to study the mixing/unmixing of CH4/CF4 in order to unveil the mechanisms that lead to this behaviour.
For the interaction potentials of CH4-CH4, CF4-CF4 and CH4-CF4 We performed extensive dispersion corrected DFT-calculations which were carefully benchmarked against very accurate CCSD(T) results. These potentials were then approximated by simple spherical potentials (e.g. of the Lennard-Jones type). The approximations were controlled by comparing the experimental structure factor and dynamical properties with Monte-Carlo simulations. We then used different Monte-Carlo-approaches from literature that are well established for studying the mixing/unmixing behaviour of molecular systems to investigate the phase diagram of CH4/CF4 at different temperatures. By comparing the results of the DFT-potentials with those of the approximated spherical potentials we were able to determine the influence of the anisotropy of the molecules on the unusual unmixing behaviour of this system.