Photodissociation of 2-bromoethanol and 2-chloroethanol at 193 nm

Journal Article · Thu Feb 15 00:00:00 EST 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.458020· OSTI ID:7170493

Hintsa, E J; Zhao, X; Lee, Y T ^[1]

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1. Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, CA (US) Department of Chemistry, University of California, Berkeley, California 94720 USA

2-Bromoethanol and 2-chloroethanol were photodissociated in a molecular beam at 193 nm. Only one primary reaction channel was observed, elimination of the halogen atom, with an average translational energy release of 33 kcal/mol. In the case of 2-bromoethanol, some of the C{sub 2}H{sub 4}OH partner fragment survived and some underwent secondary dissociation to produce C{sub 2}H{sub 4} and OH. The surviving C{sub 2}H{sub 4}OH contained up to 43 kcal/mol of internal energy, far more than the expected C{sub 2}H{sub 4}-OH bond energy of {similar to}28 kcal/mol. The initial C--Br recoil occurs with a large exit impact parameter and leaves most of the internal energy in C{sub 2}H{sub 4}OH rotation, creating rotationally metastable fragments. The angular distributions of the secondary C{sub 2}H{sub 4} and OH products were strongly forward--backward peaked with respect to the primary (C{sub 2}H{sub 4}OH) velocity vector, consistent with the decay of a long-lived complex in which the total angular momentum is perpendicular to the velocity vector and mainly carried away as orbital angular momentum. This effect is analogous to that observed in the decay of similar long-lived complexes in crossed molecular beam experiments.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7170493
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 92:4; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ALCOHOLS
BEAMS
CHEMICAL REACTIONS
DECOMPOSITION
DISSOCIATION
ELECTROMAGNETIC RADIATION
FAR ULTRAVIOLET RADIATION
HYDROXY COMPOUNDS
MOLECULAR BEAMS
ORGANIC BROMINE COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADIATIONS
ULTRAVIOLET RADIATION