These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
Cyclohexyl Radical Photodissociation Dynamics.pdf (3.46 MB)

Photodissociation Dynamics of the Cyclohexyl Radical from the 3p Rydberg State at 248 nm

submitted on 16.03.2021, 23:50 and posted on 17.03.2021, 13:17 by Isaac Ramphal, Mark Shapero, Daniel Neumark
The photodissociation of jet-cooled cyclohexyl was studied by exciting the radicals to their 3p Rydberg state using 248 nm laser light and detecting photoproducts by photofragment translational spectroscopy. Both H-atom loss and dissociation to heavy fragment pairs are observed. The H-atom loss channel exhibits a two-component translational energy distribution. The fast photoproduct component is attributed to impulsive cleavage directly from an excited state, likely the Rydberg 3s state, forming cyclohexene. The slow component is due to statistical decomposition of hot cyclohexyl radicals that internally convert to the ground electronic state prior to H-atom loss. The fast and slow components are present in a ~0.7:1 ratio, similar to findings in other alkyl radicals. Internal conversion to the ground state also leads to ring-opening followed by dissociation to 1-buten-4-yl + ethene in comparable yield to H-loss, with the C4H7 fragment containing enough internal energy to dissociate further to butadiene via H-atom loss. A very minor ground-state C5H8 + CH3 channel is observed, attributed predominantly to 1,3-pentadiene formation. The ground-state branching ratios agree well with RRKM calculations, which also predict C4H6 + C2H5 and C3H6 + C3H5 channels with similar yield to C5H8 + CH3. If these channels were active it was at levels too low to be observed.



NIH S10OD024998

NIH S10OD023532


Email Address of Submitting Author


University of California Berkeley


United States

ORCID For Submitting Author


Declaration of Conflict of Interest

No conflicts of interest.