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| Titel |
Laboratory measurements of the anomalous isotopic composition of ozone |
| VerfasserIn |
Marion Früchtl, Thomas Röckmann |
| 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 |
250058021
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| Zusammenfassung |
| Ozone is of great importance for the chemistry of the atmosphere and its isotopic signature
affects that of many other trace constituents. Due to differences in chemical and physical
properties, most of the isotope fractionations are dependent on mass and follow the
fractionation (MDF) equation Δ17O = δ17O – 0.52 δ18O. However, many atmospheric
components show an oxygen isotope anomaly, defined as the excess 17O over what
is expected based on 18O isotopic abundances. The processes that generate such
deviations in 17O are termed mass-independent fractionations (MIF). The ozone
formation reaction is the most important example for a reaction that leads to the
formation of a mass-independent isotope effect. To what degree ozone destruction
processes also influence the isotopic composition of O3 is still a subject of intense
debate.
Within the framework of INTRAMIF (Initial Training Network on Mass-Independent
Fractionation) we are setting up new experiments to characterize the influence of such O3
destruction reactions on the anomalous isotopic composition of O3 and important isotope
transfer reactions in the atmosphere and in this presentation we present the experimental
setup and first results.
We first examined the reproducibility of our experimental system. Experiments were then
carried out under different photochemical conditions, and the first experiments focus on the
influence of wavelengths used. To measure the O3isotopic composition precisely,
after the experiment ozone is collected in a cold trap, which allows quantitative
collection of O3 at the triple point temperature of nitrogen (63 K). To measure the
oxygen isotopes in O3by isotope ratio mass spectrometry, O3 is converted to O2. |
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