Improved general-purpose five-point model for water: TIP5P/2018

TL;DR

The paper introduces TIP5P/2018, an improved five-point water model derived from ab initio electrostatic potentials, which better reproduces thermodynamic and rotational properties but overestimates dielectric constant due to quadrupole moment issues.

Contribution

A new five-point water model, TIP5P/2018, with charges derived from ab initio data, improving thermodynamic and rotational properties over previous models.

Findings

Enhanced isothermal compressibility behavior.

Better thermodynamic and rotational property predictions.

Overestimation of dielectric constant due to quadrupole moment.

Abstract

A new five point potential for liquid water, TIP5P/2018, is presented along with the techniques used to derive its charges from ab initio per-molecule electrostatic potentials in the liquid phase using the split charge equilibration (SQE) of Nistor et al. [J. Chem. Phys. 125, 094108 (2006)]. By taking the density and diffusion dependence on temperature as target properties, significant improvements to the behavior of isothermal compressibility were achieved along with improvements to other thermodynamic and rotational properties. While exhibiting a dipole moment close to ab initio values, TIP5P/2018 suffers from a too small quadrupole moment due to the charge assignment procedure and results in an overestimation of the dielectric constant.