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The reaction H + C4H2 - Absolute rate constant measurement and implication for atmospheric modeling of TitanThe absolute rate constant for the reaction H + C4H2 has been measured over the temperature (T) interval 210-423 K, using the technique of flash photolysis-resonance fluorescence. At each of the five temperatures employed, the results were independent of variations in C4H2 concentration, total pressure of Ar or N2, and flash intensity (i.e., the initial H concentration). The rate constant, k, was found to be equal to 1.39 x 10 to the -10th exp (-1184/T) cu cm/s, with an error of one standard deviation. The Arrhenius parameters at the high pressure limit determined here for the H + C4H2 reaction are consistent with those for the corresponding reactions of H with C2H2 and C3H4. Implications of the kinetic carbon chemistry results, particularly those at low temperature, are considered for models of the atmospheric carbon chemistry of Titan. The rate of this reaction, relative to that of the analogous, but slower, reaction of H + C2H2, appears to make H + C4H2 a very feasible reaction pathway for effective conversion of H atoms to molecular hydrogen in the stratosphere of Titan.
Document ID
19860049585
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Nava, D. F.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mitchell, M. B.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Stief, L. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1986
Publication Information
Publication: Journal of Geophysical Research
Volume: 91
ISSN: 0148-0227
Subject Category
Lunar And Planetary Exploration
Accession Number
86A34323
Funding Number(s)
CONTRACT_GRANT: NSG-5173
Distribution Limits
Public
Copyright
Other

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