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Mie potentials for phase equilibria calculations: application to alkanes and perfluoroalkanes
Jeffrey J Potoff1, Damien A Bernard-Brunel
1Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan 48202, USA. jpotoff@chem1.eng.wayne.edu
The Journal of Physical Chemistry. B
|October 15, 2009
Summary
New transferable united-atom force fields accurately predict properties of alkanes and perfluorocarbons. Adjusting the Lennard-Jones potential improves vapor pressure and liquid density predictions for these important chemical compounds.
Area of Science:
- Chemical Physics
- Computational Chemistry
- Thermodynamics
Background:
- Developing accurate predictive models for molecular behavior is crucial in chemistry and materials science.
- United-atom force fields offer a computationally efficient approach to simulating molecular systems.
- Existing force fields often require specific parameterization for different classes of molecules, limiting their transferability.
Purpose of the Study:
- To develop and validate transferable united-atom force fields for normal alkanes and perfluorocarbons.
- To investigate the impact of modifying the repulsive exponent in Lennard-Jones potentials on predictive accuracy.
- To accurately determine key thermodynamic properties, including vapor pressures and liquid densities.
Main Methods:
- Utilized n-6 Lennard-Jones potentials for united-atom force fields.
- Employed histogram-reweighting Monte Carlo simulations in the grand canonical ensemble.
- Simulated vapor-liquid coexistence curves, vapor pressures, heats of vaporization, and critical points.
Main Results:
- Achieved high accuracy in reproducing saturated liquid densities (within 1% of experiment) for all studied molecules.
- Predicted vapor pressures within 3% for normal alkanes and 6% for perfluorocarbons.
- Demonstrated excellent agreement with experimental data for binary mixture vapor-liquid equilibria (propane + pentane).
Conclusions:
- The developed transferable force fields provide accurate predictions for normal alkanes and perfluorocarbons.
- Adjusting the repulsive exponent of the Lennard-Jones potential enhances the predictive power of the force fields.
- These models show promise for simulating complex mixtures and advancing molecular simulations in chemical engineering.
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