A Direct Two-Dimensional Pressure Formulation in Molecular Dynamics

Abstract

Coupling of statistical properties from atomistic simulations to continuum is essential to model many multi-scale phenomena. Often, the system under consideration will be homogeneous in twodimensions (2-D). But due to the existing coupling methods, the property estimation takes place in three-dimensions (3-D) and then averaged to 2-D, which is computationally expensive due to the 3-D convolutions. A direct 2-D pressure or stress estimation model is lacking in literature. In this work, we develop a direct 2-D pressure field estimation method which is much faster than 3-D methods without losing accuracy. The method is validated with MD simulations on two systems: a liquid film and a cylindrical drop of argon suspended in surrounding vapor. This formulation will enable the study of 2-D fundamental phenomena like passive liquid flows in microlayer, as well as facilitate the coupling of atomistic and continuum simulations with reduced computational cost.