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| Titel |
Absolute rate constant and O(3P) yield for the O(1D)+N2O reaction in the temperature range 227 K to 719 K |
| VerfasserIn |
S. Vranckx, J. Peeters, S. A. Carl |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 8, no. 20 ; Nr. 8, no. 20 (2008-10-28), S.6261-6272 |
| Datensatznummer |
250006426
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| Publikation (Nr.) |
 copernicus.org/acp-8-6261-2008.pdf |
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| Zusammenfassung |
| The absolute rate constant for the reaction that is the major source of
stratospheric NOx, O(1D)+N2O → products, has been
determined in the temperature range 227 K to 719 K, and, in the temperature
range 248 K to 600 K, the fraction of the reaction that yields O(3P).
Both the rate constants and product yields were determined using a
recently-developed chemiluminescence technique for monitoring O(1D)
that allows for higher precision determinations for both rate constants,
and, particularly, O(3P) yields, than do other methods. We found the
rate constant, kR1, to be essentially independent of temperature between
400 K and 227 K, having a value of (1.37±0.11)×10−10 cm3 s−1,
and for temperatures greater than 450 K a marked decrease in rate
constant was observed, with a rate constant of only (0.94±0.11)×10−10 cm3 s−1 at 719 K. The rate constants determined over the 227 K–400 K
range show very low scatter and are significantly greater, by 20%
at room temperature and 15% at 227 K, than the current recommended
values. The fraction of O(3P) produced in this reaction was determined
to be 0.002±0.002 at 250 K rising steadily to 0.010±0.004 at
600 K, thus the channel producing O(3P) can be entirely neglected in
atmospheric kinetic modeling calculations. A further result of this study is
an expression of the relative quantum yields as a function of temperature
for the chemiluminescence reactions (kCL1)C2H + O(1D) → CH(A) + CO
and (kCL2)C2H + O(3P) → CH(A) + CO,
both followed by CH(A) → CH(X) + hν, as
kCL1(T)/kCL2(T)=(32.8T−3050)/(6.29T+398). |
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