UV photodissociation dynamics of allyl radical by photofragment translational spectroscopy
- Department of Chemistry, University of California, Berkeley, California 94720 (United States)
Photodissociation of the allyl radical, CH{sub 2}CHCH{sub 2}, has been studied using the method of molecular beam photofragment translational spectroscopy following excitation to the {tilde C}(2thinsp{sup 2}B{sub 1}) and {tilde A}(1thinsp{sup 2}B{sub 1}) states by 248 and 351 nm photons. Two different primary channels have been detected following 248 nm excitation: H-atom loss (84{percent}) and CH{sub 3} elimination (16{percent}). From the product translational energy distribution and polarization dependence studies, dissociation processes from the ground-state C{sub 3}H{sub 5} potential energy surface are inferred for both wavelengths. At 248 nm there may also be a contribution to the H-atom loss channel from predissociation by a higher electronically excited state. Rice{endash}Ramsperger{endash}Kassel{endash}Marcus (RRKM) calculations show that the formation of cyclopropene is not important, while formation of allene and methylacetylene from dissociation of 1- and 2-propenyl radicals are important reaction pathways at both wavelengths. Translational energy distributions peaking well away from zero provide evidence for CH{sub 3} elimination directly from an allylic structure through a four-member cyclic transition state. {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 658477
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 13 Vol. 109; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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