Exploring the utility of coarse-grained water models for computational studies of interfacial systems

Abstract

Molecular dynamics simulations have become a standard tool for the investigation of biological and soft matter systems. Water models serve as the basis of force fields used in molecular dynamics simulations of these systems. This article reports on an examination of the utility of a set of coarse-grained (CG) water models, with different resolutions, interaction potentials (Lennard-Jones, Morse), and cut-off distances. The relationships between the parameters under specific choices of the above options and the thermodynamic properties, such as density, surface tension, and compressibility, were found to fit simple mathematical equations. The limits of applicability of these CG water models were explored by checking the melting temperature. If a CG site is mapped to one or two real water molecules, a simple model with appropriate combinations of cut-off distances, functional forms, and parameters can be found to simultaneously match the experimental values of density, surface tension, and compressibility under ambient conditions. If more water molecules are included in a CG site, either the melting temperature approaches or surpasses room temperature, or the surface tension and compressibility cannot both be matched simultaneously. In striving for computational efficiency, it is still possible to find a simple CG water model with three water molecules contained in a CG bead that generates a liquid state of water with realistic values of density, surface tension and compressibility at ambient condition, but coarser models are not recommended.

Coarse-grained molecular dynamics studies of the structure and stability of peptide-based drug amphiphile filaments

“…In the SDK CGed water, each CGed water bead represents three water molecules. 78 The total potential energy function, U , including intra and intermolecular CGed bead potentials, is defined as follows: $$U=U_{\mathrm{italicbond}}+U_{\mathrm{italicangle}}+U_{\mathrm{italicdihe}}+U_{LJ}+U_{\mathrm{italicelec}}$$…”

SAFT-γ Force Field for the Simulation of Molecular Fluids. 1. A Single-Site Coarse Grained Model of Carbon Dioxide

“…For example, Nielsen et al 17 employed a CG model for n-alkanes parameterized to reproduce surface tension data using a (9,6) Mie potential. He et al 53 followed a similar approach to obtain Mie potential parameters for the calculation of the surface tension in CG models of water. Shelley and co-workers 15,54,55 developed force-fields based on the Mie potential for the non-bonded interaction for the CG simulations to study the self-assembly of phospholipids 15,54 and diblock copolymers.…”

Comparative assessment of the ELBA coarse-grained model for water

“…In particular, the investigation of water by computer simulation has been a very active research area for about four decades now; multitudes of models have been developed, at many levels of abstraction [3][4][5][6][7][8][9][10][11].…”