How to build a better pair potential for water

Abstract

With the objective of improving the effective pair potentials for water, we develop a potential model that employs diffuse charges, in addition to the usual point charges, on the oxygen and hydrogen atoms, to account for charge penetration effects. The potential has better transferability from the liquid to gaseous phases since, unlike many existing models, it does not require an enhanced dipole moment. As a result it accurately reproduces the structural and thermodynamic properties of water over a wide range of conditions. Moreover, by allowing for electronic polarization when evaluating the total dipole moment of the simulated fluid, the model leads to the correct value of the dielectric constant for virtually any state point. At room temperature the calculation produces an average dipole moment of 3.09 D, in accord with recent theoretical and experimental evaluations. This supports the idea that induction effects in water are more important than previously expected.

Polarizable Atomic Multipole Water Model for Molecular Mechanics Simulation

“…14 Another recently proposed scheme attempts to account for penetration effects and polarization with a formally pairwise model based on screening of diffuse charges at close range. 15 Previous attempts to parametrize a polarizable water model applicable across multiple phases date back to the "polarizable electropole" model of Barnes et al 16 that treated electrostatics via a single site carrying the experimental dipole and quadrupole moments and isotropic dipole polarizability. An interesting polarizable and dissociable potential was suggested by Stillinger and David and applied to water clusters and ion monohydrates.…”

Evaluation of various water models for simulation of adsorption in hydrophobic zeolites

“…The most popular model is Tip4p [26], which has been used by Beauvais et al [18] to describe the location of the sodium cations in FAU in the presence of water; by Di Lella et al [19] to calculate the adsorption isotherms and cation distribution in FAU and MFI; by Trzpit et al [20] and Yang et al [21] to study water diffusion in MFI or by Cailliez et al [22] to study the interaction of water with the possible defects of the zeolite MFI. Desbiens et al [11,23] computed adsorption isotherms in MFI with different partial charges for the framework atoms not only with the Tip4p water model [26], but also with the Tip5p [27], MSPC/E [28] and the polarisable DEC [29] model. Ramachandran et al [13] simulated adsorption of water in MFI with Tip4p [26] and SPC/E [30], trying to reproduce small defects in the framework with extra water molecules.…”

Exp6-polar thermodynamics of dense supercritical water

“…Nevertheless, classical empirical models of water remain very successful in capturing its behavior under a broad spectrum of conditions. These models, which usually assume a rigid geometry, point charges and no polarizability [12,15] remain much studied [17] due to their effectiveness and versatility; enhanced variants of this basic motif have also been considered [16]. Despite their simplicity such representations of the water molecule are still too complicated to be efficiently analyzed with the tools of statistical mechanics.…”