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Titel |
Isotope effect in the formation of H2 from H2CO studied at the atmospheric simulation chamber SAPHIR |
VerfasserIn |
T. Röckmann, S. Walter, B. Bohn, R. Wegener, H. Spahn, T. Brauers, R. Tillmann, E. Schlosser, R. Koppmann, F. Rohrer |
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 ; 10, no. 12 ; Nr. 10, no. 12 (2010-06-16), S.5343-5357 |
Datensatznummer |
250008556
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Publikation (Nr.) |
copernicus.org/acp-10-5343-2010.pdf |
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Zusammenfassung |
Formaldehyde of known, near-natural isotopic composition was photolyzed in
the SAPHIR atmosphere simulation chamber under ambient conditions. The
isotopic composition of the product H2 was used to determine the
isotope effects in formaldehyde photolysis. The experiments are sensitive to
the molecular photolysis channel, and the radical channel has only an
indirect effect and cannot be effectively constrained. The molecular channel
kinetic isotope effect KIEmol, the ratio of photolysis frequencies
j(HCHO→CO+H2)/j(HCDO→CO+HD) at surface pressure, is determined
to be KIEmol=1.63−0.046+0.038. This is similar to the kinetic
isotope effect for the total removal of HCHO from a recent relative rate
experiment (KIEtot=1.58±0.03), which indicates that the KIEs in
the molecular and radical photolysis channels at surface pressure (≈100 kPa) may not be as different as described previously in the literature. |
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