Advanced models for water simulations

Abstract

Molecular simulations of water using classical, molecular mechanic potential energy functions have enjoyed a 50-year history of development, and much has been learned regarding their parameterization and the essential physics that must be captured in order to reproduce water properties across the phase diagram and across system sizes, from the dimer to the condensed phase. While pairwise-additive force fields using fixed, point charge-based electrostatics have dominated this history owing to computational cost, their limitations in transferability are being recognized, owing particularly to the lack of many-body effects, as well as an inherent difficulty in capturing quantum mechanical effects that become important at short intermolecular separation. This has spurred an impressive development of novel functional forms and parameterization schemes to account for such effects, especially the leading many-body effect of polarization. This review discusses recent efforts in the development of advanced models of water, particularly with regard to important details of their parameterization from quantum mechanical or experimental data, the development of novel functional forms including machine learning-based models, and algorithms that reduce the computational cost of polarization dramatically, permitting them to potentially become competitive with pairwise-additive models as the standby of condensed-phase simulation. These technical developments are appraised based on their ability to impact numerical calculations on water, particularly the condensed phase, and it is hoped that this article provides a clear connection between the essential physics captured by the model and their fitness across a range of environments.

Systematic Optimization of Water Models Using Liquid/Vapor Surface Tension Data

“…1,2 Due to the availability of plentiful experimental and firstprinciples quantum mechanical data, water is a popular testing application for developing new force field models and new approaches to developing models. [3][4][5][6][7] Among the most widely used physics-based water models today are the TIP3P and TIP4P models introduced in the 1980s, 8 which employ well-established functional forms dating back to the 1930s 9 consisting of a rigid molecular geometry, fixed atomic partial charges, and Lennard-Jones interactions.…”

Ab initiomolecular dynamics studies of hydroxide coordination of alkaline earth metals and uranyl

“…Recently, molecular dynamics simulations (MD) have gained popularity as method for investigating such dynamical processes. [20][21][22][23][24] Ab Initio Molecular Dynamics (AIMD), in the form of Born-Oppenheimer Molecular Dynamics (BOMD) or Car-Parrinello Molecular Dynamics (CPMD) [25][26][27] uses quantum chemical techniques to determine interatomic interactions. One of the main advantages of AIMD is that it can be used to study chemical bond-breaking and formation, 28 as such it has been used to study proton transport through water, 29 hydrogen bonding 30 and the microsolvation of ions.…”

Three‐site and five‐site fixed‐charge water models compatible with AMOEBA force field

“…Classical water force fields (FFs) play central roles in computer molecular modeling as many chemical and biophysical processes happen in aqueous solutions . Depending on whether or not the polarization effect is explicitly considered, most water FFs can be divided into two classes.…”

“…As the polarization effect is highly environmental dependent, it is highly realized that the fixed‐charge models fitting only to bulk water properties are not well suited for solutions especially for highly charged biological molecules . The AMOEBA is one of the popular polarizable FFs, where many‐body effects are explicitly taken into account via a linear polarization supposition that can closely reproduce the high‐level quantum potential energy surface.…”

“…[30,31] As the polarization effect is highly environmental dependent, it is highly realized that the fixed-charge models fitting only to bulk water properties are not well suited for solutions especially for highly charged biological molecules. [1][2][3] The AMOEBA is one of the popular polarizable FFs, [12,32] where many-body effects are explicitly taken into account via a linear polarization supposition that can closely reproduce the highlevel quantum potential energy surface. The initial version of AMOEBA water, AMOEBA03, [12] was fitted to QM data of a series of water clusters and experimental measurements for liquid properties (ρ and ΔH vap ) at ambient conditions.…”