title: Translational, rotational and vibrational relaxation dynamics of a solute molecule in a non-interacting solvent.
abstract: Spectroscopically observing the translational and rotational motion of solute molecules in liquid solutions is typically impeded by their interactions with the solvent, which conceal spectral detail through linewidth broadening. Here we show that unique insights into solute dynamics can be made with perfluorinated solvents, which interact weakly with solutes and provide a simplified liquid environment that helps to bridge the gap in our understanding of gas- and liquid-phase dynamics. Specifically, we show that in such solvents, the translational and rotational cooling of an energetic CN radical can be observed directly using ultrafast transient absorption spectroscopy. We observe that translational-energy dissipation within these liquids can be modelled through a series of classic collisions, whereas classically simulated rotational-energy dissipation is shown to be distinctly faster than experimentally measured. We also observe the onset of rotational hindering from nearby solvent molecules, which arises as the average rotational energy of the solute falls below the effective barrier to rotation induced by the solvent.
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.|Department of Chemistry, Fort Lewis College, Durango, Colorado 81301, USA.
authors: Michael P
authors: MP
authors: Grubb
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
authors: Philip M
authors: PM
authors: Coulter
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
authors: Hugo J B
authors: HJ
authors: Marroux
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
authors: Balazs
authors: B
authors: Hornung
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
authors: Ryan S
authors: RS
authors: McMullen
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
authors: Andrew J
authors: AJ
authors: Orr-Ewing
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
authors: Michael N R
authors: MN
authors: Ashfold