An Explanation of the Density Maximum in Water

An explanation of the anomalous density maximum in water near 4 °C can be given in terms of a competition between the presence of open second-neighbor oxygen-oxygen structure at 4.5 Å and a dense second-neighbor structure obtained from the bending of hydrogen bonds. Since no computational model of water has provided an explanation of this anomaly, altering the water-water potential to create more realistic interactions in the second-neighbor shell is proposed. Support for this idea is provided here by considering the exactly soluble Takahashi fluid model.