Assessing the accuracy of improved force‐matched water models derived from Ab initio molecular dynamics simulations

Abstract

The accuracy of water models derived from ab initio molecular dynamics simulations by means on an improved force-matching scheme is assessed for various thermodynamic, transport, and structural properties. It is found that although the resulting force-matched water models are typically less accurate than fully empirical force fields in predicting thermodynamic properties, they are nevertheless much more accurate than generally appreciated in reproducing the structure of liquid water and in fact superseding most of the commonly used empirical water models. This development demonstrates the feasibility to routinely parametrize computationally efficient yet predictive potential energy functions based on accurate ab initio molecular dynamics simulations for a large variety of different systems. © 2016 Wiley Periodicals, Inc.

On the validity of the Stokes–Einstein relation for various water force fields

“…Note also that the calculated fractional exponents for the case of the TIP4P/2005f MD simulations reported by Guillaud et al [27] are in excellent agreement with the values calculated from the experimental data reported by Dehaoui et al [11]. The poor agreement of the calculated fractional exponents for the cases of TIP4P-TPSS, TIP4P-TPSS-D3 and Huang et al water models (MD data reported by Koster et al [35]) is a result of their poor performance in predicting accurately the densities, as well as the self-diffusivities and shear viscosities of water. An overall picture of all the exponents t that were calculated during the analysis performed in the current study is shown in Figure 4.…”

“…It is important to note that due to the more demanding nature of the calculation that is required for the shear viscosity of water (especially at low temperatures [38]); MD simulations are less readily available. In addition to the references that are shown in Table 1, shear viscosity studies for various water force fields have also been reported by Fuhrmans et al [43], Raabe and Sadus [44], Fuentes-Azcatl and Alejandre [45], Fuentes-Azcatl et al [46], Ding et al [47], and Köster et al [48]. The classical hydrodynamic theory of Stokes-Einstein (SE) provides a link between the intra-diffusion coefficient D (also applicable to the self-diffusion coefficient) of a particle and its radius r in a continuum with shear viscosity, η.…”

Impact of intermolecular vibrational coupling effects on the sum-frequency generation spectra of the water/air interface

“…To explicitly consider nuclear quantum effects (NQE) in a computational efficient way, the ring polymer contraction scheme was used with a cutoff value of σ = 5 Å to reduce the electrostatic potential energy and force evaluations to a single Ewald sum, in order to speed up the calculations [52]. This is to say that 32 ring-polymer beads were employed to converge all relevant properties [47,52,[56][57][58][59][60], while the computationally expensive part of the electrostatic interactions were contracted to the centroid only. In all simulations, using a discretised integration timestep of 0.1 fs, the system was first equilibrated 10 ps in the canonical ensemble, before microcanonical ensemble averages were computed over the following 8 ps, resulting in a total statistics of 2 ns to compute the present SFG spectra.…”

Benchmark Assessment of Molecular Geometries and Energies from Small Molecule Force Fields

“…Indeed, many examples serve to highlight the limitations of force fields. [12][13][14][15][16] Our focus in this work is on force fields for small molecules, which are instrumental in drug discovery for instance, evaluating binding free energies and modeling ligand binding poses. Relatively few literature studies evaluate force field accuracy on general small drug-like molecules, in contrast to force fields for proteins, [17][18][19][20][21][22][23][24][25] nucleic acids, [26][27][28] carbohydrates, [29][30][31][32] and other specific chemical systems.…”