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

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 photofragment translational spectroscopy. Both H atom loss dissociation heavy fragment pairs are observed. channel exhibits a two-component energy distribution. fast photoproduct component is attributed impulsive cleavage directly from an excited state, likely 3s forming cyclohexene. slow due statistical decomposition hot that internally convert ground electronic prior loss. components present in ∼0.7:1 ratio, similar findings other alkyl radicals. Internal conversion also leads ring-opening followed 1-buten-4-yl + ethene comparable yield H-loss, with C4H7 containing enough internal dissociate further butadiene via A very minor ground-state C5H8 CH3 observed, predominantly 1,3-pentadiene formation. branching ratios agree well RRKM calculations, which predict C4H6 C2H5 C3H6 C3H5 channels CH3. If these were active, it at levels too low be