Dielectric response with short-ranged electrostatics

Abstract

The dielectric nature of polar liquids underpins much of their ability to act as useful solvents, but its description is complicated by the long-ranged nature of dipolar interactions. This is particularly pronounced under the periodic boundary conditions commonly used in molecular simulations. In this article, the dielectric properties of a water model whose intermolecular electrostatic interactions are entirely short-ranged are investigated. This is done within the framework of local molecular-field theory (LMFT), which provides a well-controlled mean-field treatment of long-ranged electrostatics. This short-ranged model gives a remarkably good performance on a number of counts, and its apparent shortcomings are readily accounted for. These results not only lend support to LMFT as an approach for understanding solvation behavior, but also are relevant to those developing interaction potentials based on local descriptions of liquid structure.

Self-Consistent Determination of Long-Range Electrostatics in Neural Network Potentials

“…where = 78.4 is the dielectric constant of water. The χ 0 zz (k) predicted by our SCFNN model is consistent with the expected behavior at small k. In contrast, shortrange models, like the GT system 42 and the Behler-Parrinello model, significantly deviate from the expected asymptotic value. Consequently, these short-range models are expected to have difficulties describing the dielectric screening that is important in nonuniform systems 25,35,37,39,42 , for example.…”

“…By making a physically meaningful choice for σ, the GT system can describe the structure of bulk liquids with high accuracy but with a fraction of the computational cost. Moreover, the GT system has served as a useful short-range component system when modeling the effects of long-range fields 35,37,39,41,42 . Here, we choose σ to be 4.2 Å (8 Bohr), which is large enough for the GT system to accurately describe hydrogen bonding and the local structure of liquid water [32][33][34][35][36] .…”

“…Though the short-range structure exemplified by the radial distribution function is insensitive to long-range interactions, long-range correlations are not. For example, the longitudinal component of the dipole density or polarization correlation function evaluated in reciprocal space, χ 0 zz (k), was recently shown to be sensitive to longrange interactions 42 . This correlation function is defined according to…”

“…To do so, we performed finite-field simulations at constant displacement field, D. These finite-D simulations 51 can be naturally combined with our SCFNN model, unlike many other neural network models. Following previous work 42 , we use D = Dẑ, vary the magnitude of the displacement field from D = 0 V/ Å to D = 0.4 V/ Å, and examine the polarization, P , induced in water. As shown in Fig.…”

On the role of long-range electrostatics in machine-learned interatomic potentials for complex battery materials

“…37 This is presumably because these systems are highly isotropic, so that long-range interactions average out. 38 Consequently, short-ranged ML potentials are now commonly applied to study polar and even ionic systems. 34,[39][40][41] However, the importance of long-range effects will clearly depend on the material and property of interest and thus demands more systematic scrutiny.…”