We study the molecular rotation of the protic room-temperature ionic liquid ethylammonium nitrate with dielectric relaxation spectroscopy and femtosecond-infrared spectroscopy (fs-IR) of the ammonium N-H vibrations. The results suggest that the rotation of ethylammonium ion takes place via large angular jumps. Such nondiffusive reorientational dynamics is unique to strongly hydrogen-bonded liquids such as water and indicates that the intermolecular interaction is highly directional in this class of ionic liquids.

ACS
doi.org/10.1021/jz301334j
J. Phys. Chem. Lett.
Ultrafast Spectroscopy

Hunger, J., Sonnleitner, T., Liu, L., Buchner, R., Bonn, M., & Bakker, H. (2012). Hydrogen-bond dynamics in a protic ionic liquid : evidence of large-angle jumps. J. Phys. Chem. Lett., 3(20), 3034–3038. doi:10.1021/jz301334j