Semi-infinite boundary conditions for the simulation of interfaces: The Ar/CO2(s) model revisited

We propose a method to account for the long tail corrections of dispersive forces in inhomogeneous systems. This method deals separately with the two interfaces that are usually present in a simulation setup, effectively establishing semi-infinite boundary conditions that are appropriate for the study of the interface between two infinite bulk phases. Using the wandering interface method, we calculate surface free energies of vapor–liquid, wall–liquid, and wall–vapor interfaces for a model of Lennard– Jones argon adsorbed on solid carbon dioxide. The results are employed as input to Young’s equation, and the wetting temperature located. This estimate is compared with predictions from the method of effective interface potentials and good agreement is found. Our results show that truncating Ar–Ar interactions at two and a half molecular diameters results in a dramatic decrease of the wetting temperature of about 40%.
We would like to thank Marcus Müller for suggesting us to describe the cutoff dependence of wetting properties by means of the sharp-kink approximation (cf., Sec. V). We also benefitted from helpful discussions with P. Bryk, A. Archer, and E. de Miguel. Generous financial support of Ministerio de Educacion y Ciencia through Project Nos. FIS2010- 22047-C05-05 and FIS2010-14866; Comunidad Autónoma de Madrid through Project No. MODELICO-P2009/ESP- 1691; and Junta de Andalucía through Project No. P07- FQM02884 is gratefully acknowledged.