MolecularDynamics Simulations of 1-Ethyl-3-methylimidazoliumBis[(trifluoromethyl)sulfonyl]imide Clusters and Nanodrops.

Atomisticmolecular dynamics simulations of small clusters andnanodroplets of the ionic liquid 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide[EMIM-Tf2N] subject to an external electric field wereperformed. A 125-ion-pair droplet was found to be nearly sphericalwith an isotropic distribution of cations and anions under vacuumconditions. The droplet was subjected to external electric fieldsof varying strength, and ion emission events were observed. The initiallyspherical droplet is elongated along the electric field axis, resultingin nonspherical behavior and increased net dipole values after theapplication of strong electric fields. The critical electric fieldrequired for ion field emission was determined to be 0.985 V/nm, inagreement with the experimental value of 1.0 V/nm. Excellent agreementis found in the prediction of ionic emission products for a neutral125-ion-pair droplet of the ionic liquid at an electric field strengthof 1.2 V/nm when compared to the results of two independent experiments.Small ionic liquid clusters were investigated with respect to theirthermal stabilities and were found to be thermally stable well aboveroom temperature. The role of electric fields in the dissociationof small charged ion clusters was also investigated. [ABSTRACT FROM AUTHOR]