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| Titel |
A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases |
| VerfasserIn |
J. Chen, D. S. Venables |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 4, no. 3 ; Nr. 4, no. 3 (2011-03-01), S.425-436 |
| Datensatznummer |
250001793
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| Publikation (Nr.) |
 copernicus.org/amt-4-425-2011.pdf |
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| Zusammenfassung |
| Accurate absorption spectra of gases in the near–ultraviolet (300 to 400 nm)
are essential in atmospheric observations and laboratory studies. This
paper describes a novel incoherent broadband cavity-enhanced absorption
spectroscopy (IBBCEAS) instrument for measuring very weak absorption spectra
from 335 to 375 nm. The instrument performance was validated against the
3B1-X1A1 transition of SO2. The measured
absorption varied linearly with SO2 column density and the resulting
spectrum agrees well with published spectra. Using the instrument, we report
new absorption cross-sections of O3, acetone, 2-butanone, and
2-pentanone in this spectral region, where literature data diverge
considerably. In the absorption minimum between the Huggins and Chappuis
bands, our absorption spectra fall at the lower range of reported ozone
absorption cross-sections. The spectra of the ketones agree with prior
spectra at moderate absorptions, but differ significantly at the limits of
other instruments' sensitivity. The collision-induced absorption of the
O4 dimer at 360.5 nm was also measured and found to have a maximum
cross-section of ca. 4.0×10−46 cm5 molecule−2. We
demonstrate the application of the instrument to quantifying low
concentrations of the short-lived radical, BrO, in the presence of stronger
absorptions from Br2 and O3. |
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