Phase behavior of a confined nanodroplet in the grand-canonical ensemble: the reverseliquid–vapor transition

Abstract

The equilibrium density distribution and thermodynamic properties of a Lennard-Jonesfluid confined to nanosized spherical cavities at a constant chemical potential wasdetermined using Monte Carlo simulations. The results describe both a single cavity withsemi-permeable walls as well as a collection of closed cavities formed at the constantchemical potential. The results are compared to calculations using classical densityfunctional theory (DFT). It is found that the DFT calculations give a quantitativelyaccurate description of the pressure and structure of the fluid. Both theory andsimulation show the presence of a ‘reverse’ liquid–vapor transition whereby theequilibrium state is a liquid at large volumes but becomes a vapor at small volumes.