Development of a united-atom force field for 1-ethyl-3-methylimidazolium tetracyanoborate ionic liquid

Thomas Koller, Javier Ramos, Nuno M. Garrido, Andreas P. Frba, Ioannis G. Economou

Research output: Contribution to journalArticle

21 Citations (Scopus)


Three united-atom (UA) force fields are presented for the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate, abbreviated as [EMIM] +[B(CN) 4]. The atomistic charges were calculated based on the restrained electrostatic potential (RESP) of the isolated ions (abbreviated as force field 1, FF-1) and the ensemble averaged RESP (EA-RESP) method from the most stable ion pair configurations obtained by MP2/6-31G*+ calculations (abbreviated as FF-2 and FF-3). Non-electrostatic parameters for both ions were taken from the literature and Lennard-Jones parameters for the [B(CN) 4] anion were fitted in two different ways to reproduce the experimental liquid density. Molecular dynamics (MD) simulations were performed over a wide temperature range to identify the effect of the electrostatic and non-electrostatic potential on the liquid density and on transport properties such as self-diffusion coefficient and viscosity. Predicted liquid densities for the three parameter sets deviate less than 0.5% from experimental data. The molecular mobility with FF-2 and FF-3 using reduced charge sets is appreciably faster than that obtained with FF-1. FF-3 presents a refined non-electrostatic potential that leads to a notable improvement in both transport properties when compared to experimental data.

Original languageEnglish
Pages (from-to)1115-1126
Number of pages12
JournalMolecular Physics
Issue number11-12
Publication statusPublished - 10 Jun 2012



  • electrostatic potential
  • force field development
  • ionic liquids
  • tetracyanoborate
  • united-atom model

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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