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| Titel |
Laser Spectroscopic Study on Oxygen Isotope Effects in Ozone Surface Decomposition |
| VerfasserIn |
Marco Minissale, Corinne Boursier, Hadj Elandaloussi, Yao Té, Pascal Jeseck, Christian Rouille, Thomas Zanon-Willette, Christof Janssen |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250135694
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| Publikation (Nr.) |
 EGU/EGU2016-16592.pdf |
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| Zusammenfassung |
| The isotope kinetics of ozone formation in the Chapman reaction [1]
O + O2 + M → O3 + M
(1)
provides the primary example for a chemically induced oxygen isotope anomaly and is
associated with large [2] and mass independent [3] oxygen isotope enrichments in the product
molecule, linked to a symmetry selection in the ozone formation kinetics [4–5]. The
isotopic composition of ozone and its transfer to other molecules is a powerful
tracer in the atmospheric and biogeochemical sciences [6] and serves as a primary
model for a possible explanation of the oxygen isotopic heterogeneity in the Solar
system [7–8]. Recently, the isotope fractionation in the photolytic decomposition
process
O3 + hν → O2 + O
(2)
using visible light has been studied in detail [9–10]. Much less is currently known about the
isotope fractionation in the dry deposition or in the gas phase thermal decomposition of
ozone
O3 + M → O2 + O +M.
(3)
Here we report on first spectroscopic studies of non-photolytic ozone decomposition
using a cw-quantum cascade laser at 9.5 μm. The concentration of individual ozone
isotopomers (16O3,16O16O17O, and 16O17O16O) in a teflon coated reaction cell is followed
in real time at temperatures between 25 and 150 ∘C. Observed ozone decay rates depend on
homogeneous (reaction (3)) processes in the gas phase and on heterogeneous reactions on
the wall. A preliminary analysis reveals agreement with currently recommended ozone decay
rates in the gas phase and the absence of a large symmetry selection in the surface
decomposition process, indicating the absence of a mass independent fractionation effect.
This result is in agreement with previous mass spectrometer (MS) studies on heterogeneous
ozone formation on pyrex [11], but contradicts an earlier MS study [12] on ozone surface
decomposition on pyrex and quartz. Implications for atmospheric chemistry will be
discussed.
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901—907 (1990).
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[3] Thiemens, M. H. and Heidenreich, J. E. Science 219, 1073—1075 (1983).
[4] Janssen, C., Guenther, J., Mauersberger, K. and Krankowsky, D. Phys. Chem. Chem.
Phys. 3, 4718–4721 (2001).
[5] Gao, Y. Q. and Marcus, R. A. Science 293, 259–263 (2001).
[6] Brenninkmeijer, C. A. M. et al. Chem. Rev. 103, 5125—5162 (2003).
[7] Thiemens, M. H. and Shaheen, in Treatise on Geochemistry, Holland H. and Turekian K.
eds., 151—177 (2014).
[8] Marcus, R. A. J. Chem. Phys. 121, 8201—8211 (2004).
[9] Früchtl, M., Janssen, C. and Röckmann, T. J. Geophys. Res. Atmos. 120, 4398—4416
(2015).
[10] Früchtl, M., Janssen, C., Taraborrelli, D., Gromov, S. and Röckmann, T. Geophys. Res.
Lett. (2015).
[11] Janssen, C. and Tuzson, B. J. Phys. Chem. A 114, 9709–9719 (2010).
[12] Chakraborty, S. and Bhattacharya, S. K. Chem. Phys. Lett. 369, 662–667 (2003). |
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