New intermolecular interaction potential for simulation of water and aqueous solutions in a wide range of state parameters

A new semiempirical method for derivation of additive effective potentials is proposed. Local features of the shape of the potential energy surface of water dimers are approximated by Gaussian functions. Optimum geometric parameters of nonlinear bifurcated and inverted dimers, obtained from quantum-chemical calculations are constants of the new BMW potential. Free parameters of the potential were chosen based on the results of Monte Carlo simulation of the structural and thermodynamic functions of water in a wide range of state parameters (268 K ≤ T ≤ 673 K, 0.1 MPa ≤ p ≤ 400 MPa). Calculations revealed rather high concentrations of the bifurcated and inverted dimers in the systems of H-bonds of water models. Clustering of non-tetrahedral fragments of the network of H-bonds is responsible for a microheterogeneous structure of water on the microscopic level.