Fast beam photodissociation spectroscopy and dynamics of the vinoxy radical
- Department of Chemistry, University of California, Berkeley, California 94720 (United States)
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969 (United States)
The spectroscopy and photodissociation dynamics of the vinoxy (CH{sub 2}CHO) radical {tilde B}({sup 2}A{sup {double_prime}}) {l_arrow}{tilde X}({sup 2}A{sup {double_prime}}) transition have been investigated by fast beam photofragment translational spectroscopy. We show conclusively that excitation to the {tilde B} state is followed by predissociation, even for the origin transition. Two photodissociation channels are observed: (1) CH{sub 3}+CO, and (2) H+CH{sub 2}CO, with a branching ratio of {approx}1:4. The form of the translational energy distributions imply a significant exit barrier to formation of CH{sub 3}+CO, and a considerably smaller barrier for H+CH{sub 2}CO formation. Dissociation ultimately proceeds by internal conversion to the ground electronic state; the internal conversion rate appears to be significantly enhanced by a curve crossing with either the {tilde A}({sup 2}A) or {tilde C}({sup 2}A) states. {ital Ab initio} calculations of critical points on the global potential energy surfaces aid in determining the dissociation mechanism. We present a simple model for dissociation over a barrier, the statistical adiabatic impulsive model, which satisfactorily reproduces the translational energy distributions. {copyright} {ital 1997 American Institute of Physics.}
- Research Organization:
- Lawrence Berkeley National Laboratory
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 450271
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 8 Vol. 106; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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