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Title:INTRAMOLECULAR VIBRATIONAL ENERGY REDISTRIBUTION (IVR) IN SELECTED S1 LEVELS ABOVE 1000 cm−1 IN PARA-FLUOROTOLUENE.
Author(s):Whalley, Laura E.
Contributor(s):Wright, Timothy G.; Reid, Katharine L; Davies, Julia A; Tuttle, William Duncan; Gardner, Adrian M.
Subject(s):Vibrational structure/frequencies
Abstract:With increasing vibrational wavenumber, the density of states of a molecule is expected to rise dramatically, especially so when low wavenumber torsions (internal rotations) are present, as in the case of textit{para}-fluorotoluene (textit{p}FT). This in turn is expected to lead to more opportunities for coupling between vibrational modes, which is the driving force for intramolecular vibrational energy redistribution (IVR). Previous studiesfootnote{C. J. Hammond, V. L. Ayles, D. E. Bergeron, K. L. Reid and T. G. Wright, textit{J. Chem. Phys.}, textbf{125}, 124308 (2006)}$^{,}$footnote{J. A. Davies, A. M. Green, A. M. Gardner, C. D. Withers, T. G. Wright and K. L. Reid, textit{Phys. Chem. Chem. Phys.}, textbf{16}, 430 (2014)} at higher energies have focussed on the two close lying vibrational levels at ~1200 cm$^{-1}$ in the S$_{1}$ electronic state of textit{p}FT which were assigned to two zero-order bright states (ZOBSs), whose characters predominantly involve C-CH$_{3}$ and C-F stretching modes. A surprising result of these studies was that the photoelectron spectra showed evidence that IVR is more extensive following excitation of the C-F mode than it is following excitation of the C-CH$_{3}$ mode, despite these levels being separated by only 35 cm$^{-1}$. This observation provides evidence that the IVR dynamics are mode-specific, which in turn may be a consequence of the IVR route being dependent on couplings to nearby states that are only available to the C-F mode. _x000d_ _x000d_ In this work, in order to further investigate this behaviour, we have employed resonance-enhanced multiphoton ionisation (REMPI) spectroscopy and zero-kinetic-energy (ZEKE) spectroscopy to probe S$_{1}$ levels above 1000 cm$^{-1}$ in textit{p}FT. Such ZEKE spectra have been recorded via a number of S$_{1}$ intermediate levels allowing the character and coupling between vibrations to be unravelled; the consequence of this coupling will be discussed with a view to understanding any IVR dynamics seen.
Issue Date:6/23/2017
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:APS
Genre:CONFERENCE PAPER/PRESENTATION
Type:Text
Language:English
URI:http://hdl.handle.net/2142/96814
DOI:10.15278/isms.2017.FC05
Date Available in IDEALS:2017-07-27


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