Molecular Simulation of the Vapor Liquid Equilibrium Properties of a Cylindrical Interface

The calculation of the surface tension using molecular simulation has shown great advances over the past decades, allowing to study systems containing dispersive and electrostatic interactions in mixtures of small molecules... [ view full abstract ]

The calculation of the surface tension using molecular simulation has shown great advances over the past decades, allowing to study systems containing dispersive and electrostatic interactions in mixtures of small molecules and polymers. The accurate calculation of the long-range corrections is crucial when dealing with heterogeneous systems. Efficient and fast operational expressions have been develop to calculate long-range corrections of interfacial properties such as coexisting densities, pressure and surface tension. However, these developments focus mainly on planar interfaces.

In this work, we report Monte Carlo simulations of the liquid-vapor cylindrical interface of methane, represented by a unified-atom Lennard-Jones potential. The simulation of curved interfaces needs specific long-range corrections for the calculation of the surface tension. We have investigated the impact of the cutoff radius on the vapor-liquid equilibrium properties.

In order to avoid the cutoff dependence, we have developed a specific calculation of the long-range correction energy which is directly included in the Metropolis scheme. We show that the coexisting densities are well reproduced regardless of the cutoff radius. We investigate the influence of the curvature of the interface using various cylinder sizes (see Figure).