Very Different Responses to Electromagnetic Fields in Binary Ionic Liquid-Water Solutions

The thermal and nonthermal effects of electromagnetic fields in the microwave to far-infrared frequency on binary mixtures of dimethylimidazolium hexafluorophosphate salts and water have been investigated by means of nonequilibrium molecular dynamics simulation. Significant alterations in dipole alignment, thermal response, and molecular mobility were found vis-a-vis zero-field conditions for mixtures of varying composition. Results indicate that ionic liquids respond most significantly to frequencies much lower than that of water in terms of both heating and nonthermal responses of dipole alignment and molecular mobility, and this was rationalized in terms of dipole moment magnitudes, rotational inertia, and translational field response.