From dimer to condensed phases at extreme conditions: Accurate predictions of the properties of water by a Gaussian charge polarizable model

Abstract

Water exhibits many unusual properties that are essential for the existence of life. Water completely changes its character from ambient to supercritical conditions in a way that makes it possible to sustain life at extreme conditions, leading to conjectures that life may have originated in deep-sea vents. Molecular simulation can be very useful in exploring biological and chemical systems, particularly at extreme conditions for which experiments are either difficult or impossible; however this scenario entails an accurate molecular model for water applicable over a wide range of state conditions. Here, we present a Gaussian charge polarizable model (GCPM) based on the model developed earlier by Chialvo and Cummings [Fluid Phase Equilib. 150, 73 (1998)] which is, to our knowledge, the first that satisfies the water monomer and dimer properties, and simultaneously yields very accurate predictions of dielectric, structural, vapor-liquid equilibria, and transport properties, over the entire fluid range. This model would be appropriate for simulating biological and chemical systems at both ambient and extreme conditions. The particularity of the GCPM model is the use of Gaussian distributions instead of points to represent the partial charges on the water molecules. These charge distributions combined with a dipole polarizability and a Buckingham exp-6 potential are found to play a crucial role for the successful and simultaneous predictions of a variety of water properties. This work not only aims at presenting an accurate model for water, but also at proposing strategies to develop classical accurate models for the predictions of structural, dynamic, and thermodynamic properties.

2D-Raman-THz spectroscopy: A sensitive test of polarizable water models

“…Apart from a careful parametrization, the essential difference to other water models of equal complexity are Gaussian inducible dipoles. 65,71 That solves a problem of other models such as SWM4-NDP, namely that the polarizability has to be kept smaller than the gas-phase value. A cornerstone in the parametrization of the TLnP models was to fix the dipole moment and polarizability to the corresponding experimental gas phase values (for simplicity, however, the polarizability was assumed to be isotropic).…”

Solvent reaction field potential inside an uncharged globular protein: A bridge between implicit and explicit solvent models?

“…Even explicit solvent representations have difficulty adequately representing the highly polar and tetrahedral hydrogen-bonding characteristics of water [29][30][31][32][33][34][35]86]. In particular, restricting the negative charge on the water molecule to travel strictly with the Lennard-Jones site may create adverse effects at the water-protein interface in addition to the compromises that must be made to achieve certain properties of water under a biologically relevant set of conditions [86].…”

Determination of phase diagrams via computer simulation: methodology and applications to water, electrolytes and proteins

“…Therefore it is impossible with three charge models to reproduce simultaneously the melting point and the TMD. It is likely that the inclusion of quantum effects and/or polarizability [246,247,248,249,250,251,252] …”