TIP4P/2005 can be considered as a minor modification of the successful TIP4P model of water. The parameters of the potential[1] were obtained by reproducing not only properties of the liquid phase, as usual in other potential models, but also properties of the solid phases (ices). In particular the melting point temperature and the phase diagram were also used as a target properties [2,3,4,5,6]. Details will be provided about how to determine fluid-solid and solid-solid equilibria for water and other molecular

fluids and how to use this information to improve the description of the intermolecular interactions [6]. The performance of the TIP4P/2005 model of water will be compared to that of the traditional TIP3P, TIP4P and TIP5P.

For that purpose the predictions for ten different properties of water will be compared :

1. vapour-liquid equilibria (VLE) and critical temperature; 2. surface tension; 3. densities of the different solid structures of water (ices); 4. phase diagram; 5. melting point properties; 6. maximum in density at room pressure and thermal coefficients; 7. structure of liquid water and ice; 8. equation of state at high pressures; 9. diffusion coefficient; 10. dielectric constant.

It will be shown that for almost all these ten properties the best predictions are provided by TIP4P/2005. TIP4P/2005 is probably close to the best description of water that can be achieved with a non polarizable model described by a single Lennard-Jones (LJ) site and three charges.

[1] J.L.F.Abascal and C.Vega, J.Chem.Phys., 123, 234505, (2005).

[2] E.Sanz,C.Vega, J.L.F.Abascal and L.G.MacDowell,Phys.Rev.Lett.,92, 2557011,(2004).

[3] C.Vega, E.Sanz y J.L.F.Abascal, J.Chem.Phys., 122,114507, (2005).

[4] R.G.Fernandez, J.L.F.Abascal y C.Vega, J.Chem.Phys., 124, 144506, (2006).

[5] J.L.F.Abascal y C.Vega, Phys.Rev.Lett.,98, 237801 ,(2007).

[6] C.Vega, E.Sanz, J.L.F.Abascal and E.G.Noya,J.Phys.Condens.Matt., 20,153101,(2008)