The near ultraviolet photodissociation dynamics of azomethane
- Chemical Sciences Division, Lawrence Berkeley Laboratory, and Department of Chemistry, University of California, Berkeley, California, 94720 (United States)
The photodissociation of azomethane following absorption of a single 351 nm photon was studied using the method of molecular beam photofragment translational spectroscopy. The dissociation was observed to proceed via cleavage of both C--N bonds to yield N[sub 2] and two methyl radicals. The measured time-of-flight spectra show evidence that the two methyl radicals possess unequal velocities in the azomethane center of mass suggesting that the dissociation is not symmetric. The angles between the asymptotic center-of-mass velocities for all three fragments are strongly correlated, implying that the methyldiazenyl radical (CH[sub 3]N[sub 2]) intermediate decomposes within a fraction of its rotational period. We conclude, therefore, that the dissociation is [ital concerted], not stepwise as was inferred from recent time-resolved experiments. The overall translational energy distributions for all the photofragments in the azomethane center of mass reveal that an average of 60% of the total available energy appears as translation. A possible mechanism, consistent with the experimental findings, will be proposed and discussed.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6257897
- Journal Information:
- Journal of Chemical Physics; (United States), Vol. 99:6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AZO COMPOUNDS
PHOTOLYSIS
CENTER-OF-MASS SYSTEM
CHEMICAL BONDS
DISSOCIATION
METHYL RADICALS
MOLECULAR BEAMS
NITROGEN
SYMMETRY
ULTRAVIOLET RADIATION
VELOCITY
YIELDS
ALKYL RADICALS
BEAMS
CHEMICAL REACTIONS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELEMENTS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
RADICALS
400500* - Photochemistry