Microstructure of Water At the Level of Three-particle Correlation Functions As Predicted by Classical Intermolecular Models

Abstract

We compared the microscopic structure of liquid water at ambient conditions predicted by six classical intermolecular potential models. Applying their accepted acronyms were the SPC (Simple Point Charge), SPC/E (SPC extended), MSPC/E (SPC/E modified), TIP4P (Transferable Intermolecular Potential, four point charges), TIP5P (TIP, five point charges), and the PPC (Polarizable Point Charge) intermolecular potential models. Configurations of computer simulations were used to study the structure at the level of partial three-particle correlation functions. We created contour maps for visual evaluation, calculated overlap integrals of the three-particle correlation functions of the models to quantify their similarity, and determined their distance-dependent three-particle entropy contribution. The SPC/E and the TIP4P water models generate quite similar structures, while the SPC and the MSPC/E pair exhibit the largest discrepancies. The structure of the PPC is the most ordered and the SPC structure is the most disordered among the studied interaction models.