Molecular simulation of fluids with non-identical intermolecular potentials: thermodynamic properties of 10-5 + 12-6 Mie potential binary mixtures.
General methods for combining interactions between particles characterised by non-identical intermolecular potentials are investigated. The combination methods are tested by performing molecular dynamics simulations to determine the pressure, energy, isochoric and isobaric heat capacities, thermal expansion coefficient, isothermal compressibility, Joule-Thomson coefficient, and speed of sound of 10-5 + 12-6 Mie potential binary mixtures. In addition to the two non-identical Mie potentials, mixtures are also studied with non-identical intermolecular parameters. The combination methods are compared with results obtained by simply averaging the Mie exponents. When either the energy or size parameters are non-identical, very significant differences emerge in the thermodynamic properties predicted by the alternative combination methods. The isobaric heat capacity is the thermodynamic property that is most affected by the relative magnitude of the intermolecular potential parameters and the method for combining non-identical potentials. Either the arithmetic or geometric combination of potentials provides a simple and effective way of performing simulations involving mixtures of components characterised by non-identical intermolecular potentials, which is independent of their functional form.
Technische Fakultät, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5a, 91058 Erlangen, Germany.
Thomas
T
Stiegler
Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218 Hawthorn, Victoria 3122, Australia.
Richard J
RJ
Sadus