Density profile and pressure of a confined fluid with core-softened potential: a one-dimensional model of water in a slit

The density profile and the pressure of a one-dimensional fluid with core-softened potential are calculated rigorously using the exact formula for the grand canonical partition function of a one-dimensional fluid. This core-softened potential has been used as a simple zeroth-order approximation of liquid water, which reproduces anomalous thermal expansion and predicts liquid–liquid phase transition. Our numerical results for a confined fluid suggest a highly structured density profile and pressure which are attributed to two possible packing methods of fluid particles interacting via the core-softened potential.