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| Titel |
Technical Note: VUV photodesorption rates from water ice in the 120–150 K temperature range – significance for Noctilucent Clouds |
| VerfasserIn |
M. Yu. Kulikov, A. M. Feigin, S. K. Ignatov, P. G. Sennikov, Th. Bluszcz, O. Schrems |
| 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 ; 11, no. 4 ; Nr. 11, no. 4 (2011-02-25), S.1729-1734 |
| Datensatznummer |
250009374
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| Publikation (Nr.) |
 copernicus.org/acp-11-1729-2011.pdf |
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| Zusammenfassung |
| Laboratory studies have been carried out with the aim to improve our
understanding of physicochemical processes which take place at the water
ice/air interface initiated by solar irradiation with a wavelength of
121.6 nm. It was intended to mimic the processes of ice particles
characteristic of Noctilucent Clouds (NLCs). The experimental set-up used
includes a high-vacuum chamber, a gas handling system, a cryostat with
temperature controller, an FTIR spectrometer, a vacuum ultraviolet hydrogen
lamp, and a microwave generator. We report the first results of measurements
of the absolute photodesorption rate (loss of substance due to the escape of
photoproducts into gas phase) from thin (20–100 nm) water ice samples kept
in the temperature range of 120–150 K. The obtained results show that a flow
of photoproducts into the gas phase is considerably lower than presumed in
the recent study by Murray and Plane (2005). The experiments indicate that
almost all photoproducts remain in the solid phase, and the principal
chemical reaction between them is the recombination reaction
H + OH → H2O which is evidently very fast. This means that direct
photolysis of mesospheric ice particles seems to have no significant impact
on the gas phase chemistry of the upper mesosphere. |
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