Few studies are found in literature about water/iron interface simulation, and as far as we know, none water/iron study was performed using classical method simulations, i.e. they were all performed using ab initio methods [5–10]. Jung [9], Govender [8]and Freitas [10] studied the water–iron interface using DFT and they observed that among the most stable energy adsorption sites(top, bridge and hollow) the top site showed the lowest energy adsorption. These different adsorption sites corrugate the first layer of adsorbed water, where the water–iron distance in the z axis(perpendicular to iron surface) is related to the energy site. The corrugation effect on the liquid adsorption was first simulated by Spohr [7]. His empirical model for describing water interaction with the surface depends on two factors: the water–metal distances and the water location over the metallic surface (i.e. its position in relation to sites top, bridge and hollow). However, the parameterization of the potential function was obtained by ab initio simulation of the water adsorption on a small cluster of a metallic surface. For some metals (e.g. iron), it is very hard to obtain such potential function due to the degeneracy of states and a lack of spin paring configuration near the Fermi level.