Ionic liquids in external electric and electromagnetic fields: a molecular dynamics study

The non-thermal effects of external electric and electromagnetic fields in the microwave to far-infrared frequency range and at (r.m.s.) electric field intensities of 10-3 to 0.25 V/angstrom r.m.s. on neat salts of 1,3-dimethyl-imidazolium hexafluorophosphate ([dmim][PF6]) and 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6]) have been investigated by means of non-equilibrium molecular dynamics simulation. Significant alterations in molecular mobility were found vis-a-vis zero-field conditions. Using Green-Kubo and transient time correlation function analysis, the electrical conductivity of these ionic liquids has been estimated. The results indicate that ionic liquids respond most significantly to frequencies much lower than those of smaller polar solvents such as water, although the mechanism of the field response is almost exclusively translational.