Influence of dispersive long-range interactions on transport and excess properties of simple mixtures

Abstract

The influence of dispersive long-range interactions on liquid bulk phase transport and excess properties of six binary Lennard–Jones (LJ) mixtures was studied by molecular dynamics simulation and equation of state modelling. For the transport properties, the self-diffusion coefficients, mutual diffusion coefficients, shear viscosity, and thermal conductivity were considered. For the excess properties, the excess energy, volume, Gibbs energy, and entropy were studied. Moreover, the thermodynamic factor was studied. The two components had the same size parameter in all cases, but different dispersion energies and different cross-interaction parameters. Thereby, the six resulting mixtures show three types of phase behaviour: ideal, high- and low-boiling azeotrope. For studying the influence of the dispersive long-range interactions, the results of the full LJ potential were compared to the LJ truncated and shifted (LJTS) potential applying the corresponding states principle. The dispersive long-range interactions have a significant influence on the self-diffusion and the mutual diffusion coefficients, whereas the shear viscosity and the thermal conductivity are hardly affected. For all investigated properties, the dispersive long-range interactions have practically no influence on the composition dependency.

GRAPHICAL ABSTRACT

Keywords:

• Transport properties
• molecular dynamics
• equation of state
• Lennard–Jones
• long-range interactions

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors gratefully acknowledge funding of the present work by Deutsche Forschungsgemeinschaft DFG within CRC 926 and funding by the BMBF within the WindHPC project. The simulations were carried out on the ELWE supercomputer at Regional University Computing Center Kaiserslautern under the grant TUKL-MTD. The present research was conducted under the auspices of the Boltzmann-Zuse Society of Computational Molecular Engineering.