A new intermolecular potential for simulations of methanol: The OPLS/2016 model

Abstract

In this work, a new rigid-nonpolarizable model of methanol is proposed. The model has three sites, located at the same positions as those used in the OPLS model previously proposed by Jorgensen [J. Phys. Chem. 90, 1276 (1986)]. However, partial charges and the values of the Lennard-Jones parameters were modified by fitting to an adequately selected set of target properties including solid-fluid experimental data. The new model was denoted as OPLS/2016. The overall performance of this model was evaluated and compared to that obtained with other popular models of methanol using a similar test to that recently proposed for water models. In the test, a certain numerical score is given to each model. It was found that the OPLS/2016 obtained the highest score (7.4 of a maximum of 10) followed by L1 (6.6), L2 (6.4), OPLS (5.8), and H1 (3.5) models. The improvement of OPLS/2016 with respect to L1 and L2 is mainly due to an improvement in the description of fluid-solid equilibria (the melting point is only 14 K higher than the experimental value). In addition, it was found that no methanol model was able to reproduce the static dielectric constant and the isobaric heat capacity, whereas the better global performance was found for models that reproduce the vaporization enthalpy once the so-called polarization term is included. Similar conclusions were suggested previously in the analysis of water models and are confirmed here for methanol.

The dielectric constant: Reconciling simulation and experiment

“…Another relevant study in this context is that of Gonzalez-Salgado and Vega 24 , who recently parameterised a new united atom (UA) model for methanol by fitting to a large set of thermodynamic properties, and compared its performance with several other UA models. As expected, all models significantly underestimated the dielectric constant of methanol.…”

“…A relatively simple approach is to adopt a set of scaled charges when dealing with properties that depend on the DMS, while using the standard unscaled charges when calculating properties that depend on the PES alone. This approach has been used successfully in only a few studies so far, focusing on specific molecules 13,14,[21][22][23][24] . A physical interpretation of the need for applying a scaling factor to the charges was provided by Leontyev…”

Perturbed structural dynamics underlie inhibition and altered specificity of the multidrug efflux pump AcrB

“…The whole system was solvated with a 0.15 M aqueous NaCl solution. The AMBER force field protein.fb15 57 was used to represent the protein; lipid17 (http://ambermd.org/GetAmber.php) parameters were used for the POPE molecules; the TIP3PFB model was employed for water 58 . The GAFF force-field parameters 59 for CIP and PAβN were taken from Malloci et al 53 .…”

Effect of truncating electrostatic interactions on predicting thermodynamic properties of water–methanol systems

“…These models are frequently used in benchmark studies [3][4][5][6]. In this study, we have chosen for the TraPPE [83] and OPLS/2016 [84] force fields as the TraPPE force field is widely used, and the OPLS/2016 force field is recently published. The OPLS/2016 force field is claimed to be a more accurate force field for methanol [84].…”