Core-softened fluids as a model for water and the hydrophobic effect.

An interaction model with core-softened potential in three dimensions was studied by Monte Carlo computer simulations and integral equation theory. We investigated the possibility that a fluid with a core-softened potential can reproduce anomalies found experimentally in liquid water, such as the density anomaly, the minimum in the isothermal compressibility as a function of temperature, and others. Critical points of the fluid were also determined. We provided additional arguments that the old notion, postulating that only angular-dependent interactions result in density anomaly, is incorrect. We showed that potential with two characteristic distances is sufficient for the system to exhibit water-like behavior and anomalies, including the famous density maximum. We also found that this model can properly describe the hydrophobic effect.