Phase coexistence in finite van der Waals systems

Phase coexistence in finite systems obeying van der Waals equation of state is studied by minimizing a model free energy function for a spherical liqu id droplet and a gaseous phase around it. Phase diagrams are calculated for finite systems with a large range of sizes. According to this model, the h ighest temperature where a droplet and vapour can exist in equilibrium decr eases as N-0.4, where N is the number of particles in the system. The model predicts higher equilibrium vapour pressures than molecular dynamics simul ations.