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| Titel |
HOx recycling via HO2 + isoprene-derived RO2: Direct experimental evidence |
| VerfasserIn |
Christoph B. M. Groß, Terry J. Dillon, John N. Crowley |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052830
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| Zusammenfassung |
| Recent results from field, lab and theoretical work suggest that the atmospheric oxidation of
isoprene and other important NHMCs is still inadequately represented in atmospheric
models. In low NOx conditions organic peroxy radicals (RO2) – the key intermediates in
these processes – react mainly with HO2. Depending on the substitution pattern of the RO2
these reactions either terminate or propagate radical chemistry. The propagating reaction
channels recycle HOx by direct production of OH and thus contribute to the maintenance of
the atmosphere’s oxidative capacity.
In this work for the first time OH yields for reactions of HO2 with RO2 formed during
isoprene oxidation were measured directly. We deployed a laser-based experiment
with multidiagnostic spectroscopic tools including direct detection of OH, HO2
and RO2 as well as on-line determination of precursor concentrations. Branching
ratios were derived by numerical simulations of the photochemical systems. For the
reactions of HO2 with CH3C(O)O2 and HOCH2C(O)O2 substantial OH yields were
determined. |
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