Constant chemical potential, pressure and temperature profiles in liquid–vapour equilibrium obtained by spinodal decomposition

Abstract

Constant chemical potential, pressure and temperature profiles across a slab of liquid in equilibrium with its vapour confirm that, the spinodal decomposition procedure carried on the NVT ensemble simulated via molecular dynamics produce an equilibrium system. An initial homogeneous crystalline configuration of fluid is kept in a cell with a parallelepiped shape at a density near the critical density and a temperature between the triple and critical temperatures, form a slab of liquid in equilibrium with its vapour by the spinodal decomposition phenomenon if the simulation is performed in the NVT ensemble. An elongated box favours the formation of two planar parallel surfaces along the largest side of the box. We show in this paper that the ‘three conditions’ for thermodynamic equilibrium: constant temperature, constant pressure and constant chemical potential are met for such a system.