Orlando Acevedo, University of Miami

This repository holds two different sets of OPLS-AA parameters for use in ionic liquid simulations.

1) Unscaled and 0.8 scaled OPLS-AA force field parameters (2009IL). Please see the following references for technical details:

1. doi:10.1021/ct900009a
2. doi:10.1021/acs.jctc.7b00520

2) Virtual site OPLS-AA force field parameters (VSIL). Please see the following reference for technical details:

3. doi:10.1021/acs.jpcb.7b11996
4. doi:10.3390/ijms21041190

IMPORTANT: The 2009IL and VSIL parameters should NOT be mixed! VSIL anion parameters were specifically parameterized to work exclusively with the virtual site cations.

• Gromacs 5.0.7
  • Tested with CUDA 7.5/8.0 and on CentOS 6.5/7.0
  • Heat capacity DoS calculations (g_dos) requires Gromacs 5.1.4 due to a known bug in version 5.0.7

git clone git:https://github.com/orlandoacevedo/IL.git

• Cations

  • 1-ethyl-3-methylimidazolium [EMIM]
  • 1-butyl-3-methylimidazolium [BMIM]
  • 1-octyl-3-methylimidazolium [OMIM]

• Anions

  • acetate [ACE]
  • benzoate [BNZ]
  • bis(pentafluoroethylsulfonyl)amide [NPf2]
  • bis(trifluoromethylsulfonyl)amide [NTf2]
  • bromide [Br]
  • chloride [Cl]
  • dicyanamide [DCA]
  • formate [HCOO]
  • hexafluorophosphate [PF6]
  • methylsulfate [MS]
  • nitrate [NO3]
  • perchlorate [ClO4]
  • propionate [PROP]
  • tetrachloroaluminate [AlCl4]
  • tetrafluoroborate [BF4]
  • thiocyanate [SCN]
  • tricyanomethanide [TCM]
  • trifluoromethanesulfonate [TFO]

• 2009IL - unscaled OPLS-2009IL bonded and nonbonded parameters

• 0.8*2009IL - 0.8-scaled OPLS-2009IL bonded and nonbonded parameters

• VSIL - Virtual site OPLS bonded and nonbonded parameters

  • itp, top, and pdb folders

A brief tutorial is provided in the Tutorial_[BMIM][BF4] directory. A README file will guide the user through the contruction of a [BMIM][BF4] box composed of 500 ion pairs using the OPLS-2009IL parameter set. GROMACS input files are provided to run a 40 ns MD simulation and output files are also provided for comparison. The user is guided on how to compute both the density and the heat of vaporization for the ionic liquid system.

Sambasivarao, S.V.; Acevedo, O. "Development of OPLS-AA Force Field Parameters for 68 Unique Ionic Liquids." J. Chem. Theory Comput., 2009, 5, 1038-1050. doi:10.1021/ct900009a

Doherty, B.; Zhong, X.; Gathiaka, S.; Li, B.; Acevedo, O. "Revisiting OPLS Force Field Parameters for Ionic Liquid Simulations." J. Chem. Theory Comput., 2017, 13, 6131-6145. doi:10.1021/acs.jctc.7b00520

Doherty, B.; Zhong, X.; Acevedo, O. "A Virtual Site OPLS Force Field for Imidazolium-Based Ionic Liquids" J. Phys. Chem. B, 2018, 122, 2962-2974. doi:10.1021/acs.jpcb.7b11996

Velez, C.; Doherty, B.; Acevedo, O. "Accurate Diels-Alder Energies and Endo Selectivity in Ionic Liquids using the OPLS-VSIL Force Field" Int. J. Mol. Sci., 2020, 21, 1190. doi:10.3390/ijms21041190

Contributing Authors: Brian Doherty, Symon Gathiaka, Bin Li, S.V. Sambasivarao, Caroline Velez, Xiang Zhong, and Orlando Acevedo*

Funding: Gratitude is expressed to the National Science Foundation (NSF CHE-1562205 and NSF CHE-1149604) for funding the project.

Software License: OPLS-2009IL and OPLS-VSIL. Copyright (C) 2020 Orlando Acevedo

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. https://www.gnu.org/licenses/