Surface properties of water clusters: a molecular dynamics study

Abstract

Radial local densities, local energies per molecule, orientational distribution functions, normal component of the pressure tensor and other surface properties of water are calculated, based on molecular dynamics simulations of water clusters at 300 K. Three different water models are evaluated: the rigid five-site ST2 and four-site TIP4P models; and the three-site SPC/E model, which is made flexible with respect to the angle bending. The size of the clusters is varied from 64 to 1000 water molecules. It is concluded that surface properties are highly sensitive to the choice of potential model. On the basis of the dependence of the work of cluster formation on the cluster size, the influence of the water model on the surface tension of the plane surface is discussed. None of the three models considered gives a proper value for the surface tension of water at room temperature.