Three-dimensional "Mercedes-Benz" model for water.

In this paper we introduce a three-dimensional version of the Mercedes-Benz model to describe water molecules. In this modelvan der Waals interactions and hydrogen bonds are given explicitly through a Lennard-Jones potential and a Gaussian orientation-dependent terms, respectively. At low temperature the model freezes forming Ice-I and it reproduces the main peaks of the experimental radial distribution function of water. In addition to these structural properties, the model also captures the thermodynamical anomalies of water: The anomalous density profile, the negative thermal expansivity, the large heat capacity, and the minimum in the isothermal compressibility.