Systematic Procedure To Parametrize Force Fields for Molecular Fluids

Abstract

A new strategy to develop force fields for molecular fluids is presented. The intermolecular parameters are fitted to reproduce experimental values of target properties at ambient conditions and also the critical temperature. The partial charges are chosen to match the dielectric constant. The Lennard-Jones parameters, εii and σii, are fitted to reproduce the surface tension at the vapor-liquid interface and the liquid density, respectively. The choice of those properties allows obtaining systematically the final parameters using a small number of simulations. It is shown that the use of surface tension as a target property is better than the choice of heat of vaporization. The method is applied to molecules, from all atoms to a coarse-grained level, such as pyridine, dichloromethane, methanol, and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) at different temperatures and pressures. The heat of vaporization, radial distribution functions, and self-diffusion coeficient are also calculated.

On the composition dependence of thermodynamic, dynamic and dielectric properties of water-dimethyl sulfoxide model mixtures. NPT molecular dynamics simulation results

“…It seems that further minor adjustment of these parameters in the P2 and OPLS-UA DMSO models may lead to an improvement of the results, see e.g. [62,63] for discussion of the choice of Lennard-Jones parameters. However, another possibility is to correct the parameters of the cross water -DMSO interaction, see e.g.…”

“…It was designed to reproduce the dielectric constant of water with good precision. We are not aware of similar efforts for DMSO, still a procedure of parametrization in the spirit of the work [62] can be attempted. However, it is not very likely to obtain better description of ε(X D ) for the entire composition range in this manner.…”

Composition dependence of thermodynamic, dynamic and dielectric properties of water–methanol model mixtures. Molecular dynamics simulation results with the OPLS-AA model for methanol

“…It is difficult to judge if this discrepancy influences substantially other properties discussed below. Still, it seems that either a slight re-parametrization of the potential model (similarly to the procedure applied for pure substances at the united atom level in [24,25]) or introduction of the deviations to the combination rules must be explored to reach perfect agreement with experiment for this property. In this aspect it is worth mentioning that very recently we have undertaken calculations of ρ(X m ) at the same conditions but at the level of OPLS-UA modeling and obtained better coincidence of theoretical calculations with experimental results [26].…”

Molecular dynamics simulation of microwave heating of liquid monoethanolamine (MEA): An evaluation of existing force fields

“…Our approach was to proportionately scale the partial atomic charges in these force fields with all the remaining force field parameters left unchanged. This method was first presented by Salas et al 38 to improve force fields for pyridine, dichloromethane, methanol, and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) at different temperatures and pressures. Luz et al followed the same approach to obtain an accurate force field for formamide 39 .…”