Hydration properties of Al3+ ion using empirical ion-water potential by Monte Carlo simulation

Abstract

In this work, hydration properties of Al3+ ion are investigated by statistical mechanics Monte Carlo simulations in the NpT ensemble at 298.15 K and 1 atm using an effective ion-water potential model whose parameters were developed through empirical search in configurational energy space during the course of simulations to fitting structural experimental data of the first hydration shell. Computed structural results for coordination numbers and ion-water oxygen distances for both first and second coordination shells are obtained in very good agreement with experimental observations. The hydration enthalpy predicted from this simple model is also in very good agreement with experimental values and it is quite similar to the one obtained by Wasserman et al. from the hydrated ion model. Many-body contributions investigated for an [Al(H2O)6]3+ cluster using the density functional theory in ab initio quantum mechanical calculations provide support to the effectiveness of the ion-water pair potential developed concerning many-body effects of water molecules around the ion incorporated in the fitted parameters. ©2008 Sociedade Brasileira de Química.