The shifted reflective boundary for the study of two-phase systems with molecular dynamics simulations

William d'Haeseleer (1) , Geert van den Branden (1) , Martine Baelmans (2)

1 Department of Mechanical Engineering
2 Department of Mechanical Engineering

When studying fluids with molecular dynamics simulations, periodic boundaries are usually used to model an infinite bulk fluid surrounding the primary cell. For homogeneous systems this is, as a rule, the most appropriate way. For inhomogeneous systems, e.g. systems with a fluid-vapour interface, periodic boundaries suffer some disadvantages. Therefore, an alternative for periodic boundaries, called shifted reflective boundary, is proposed for modelling such systems. From a computational point of view, this type of boundary is not more difficult to implement than periodic boundaries. It is shown that the shifted reflective boundary results in a stable spatial fluid-vapour configuration with one fluid-vapour interface, while retrieving the same numerical results for thermodynamic properties, e.g. the surface tension, as molecular dynamics simulations with periodic boundaries. Molecular dynamics simulations with shifted reflective boundaries also need fewer particles than corresponding simulations with periodic boundaries.

Mots clés: Physical Sciences

William d'Haeseleer, Geert van den Branden, Martine Baelmans. The shifted reflective boundary for the study of two-phase systems with molecular dynamics simulations. Molecular Physics, 2008, 106 (01), pp.43-56. ⟨10.1080/00268970701829740⟩. ⟨hal-00513168⟩