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Titel |
Isotope effects in N2O photolysis from first principles |
VerfasserIn |
J. A. Schmidt, M. S. Johnson, R. Schinke |
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. 17 ; Nr. 11, no. 17 (2011-09-02), S.8965-8975 |
Datensatznummer |
250010048
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Publikation (Nr.) |
copernicus.org/acp-11-8965-2011.pdf |
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Zusammenfassung |
For the first time, accurate first principles potential energy surfaces allow
N2O cross sections and isotopic fractionation spectra to be derived
that are in agreement with all available experimental data, extending our
knowledge to a much broader range of conditions. Absorption spectra of rare
N- and O-isotopologues (15N14N16O,
14N15N16O, 15N216O,
14N217O and 14N218O) calculated using
wavepacket propagation are compared to the most abundant isotopologue
(14N216O). The fractionation constants as a function of
wavelength and temperature are in excellent agreement with experimental data.
The study shows that excitations from the 3rd excited bending state,
(0,3,0), and the first combination state, (1,1,0), are important for
explaining the isotope effect at wavelengths longer than 210 nm. Only
a small amount of the mass independent oxygen isotope anomaly observed in
atmospheric N2O samples can be explained as arising from photolysis. |
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