Can simple models describe the phase diagram of water?

Abstract

The melting point of ice Ih for the TIP3P, SPC, SPC/E, TIP4P, TIP4P/Ew and TIP5P models has beendetermined by computer simulation. It has been found that the melting points of iceIh for these models are 146, 190, 215, 232, 245 and 274 K respectively. Thus fromthe models of water available so far only TIP5P reproduces the experimentalmelting point of water. The relative stability of ice II with respect to iceIh at the normal melting point has also been considered. Ice II is more stable than iceIh for the TIP3P, SPC, SPC/E and TIP5P models. Only for the TIP4P and TIP4P/Ew models is iceIh more stable than ice II at low pressures. The complete phase diagram for the SPC/E,TIP4P and TIP5P models has been computed. It has been found that SPC/E and TIP5Pdo not correctly describe the phase diagram of water. However, TIP4P provides aqualitatively correct description of the phase diagram of water. A slight modification of theparameters of the TIP4P model yields a new model, denoted as TIP4P/ice, whichreproduces the experimental melting point of water and provides an excellent description ofthe densities of all ice phases.