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| Titel |
Synchrotron radiation and long path cryogenic cells: New tools and results for modelling SF6 absorption in the 10μm atmospheric window |
| VerfasserIn |
Mbaye Faye, Vincent Boudon, Michel Loete, Pascale Roy, Laurent Manceron |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101090
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| Publikation (Nr.) |
 EGU/EGU2015-158.pdf |
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| Zusammenfassung |
| Sulfur hexa?uoride (SF6) is a heavy and stable molecule used in many sectors, such as the
electrical industry, but also as a gas tracer to model air masse motions in the Earth
atmosphere. This anthropogenic species is also an atmospheric pollutant owing to its
greenhouse effect capability. Although its six fundamental modes have been largely studied
up to now, it is not the case for the numerous hot bands that represent the most important part
of the SF6 spectrum at room temperature. So, to model correctly the SF6 atmospheric
absorption requires the knowledge of the spectroscopic parameters of all states involved in
these hot bands. Nevertheless, due to their overlapping, a direct analysis of the
hot bands near the 10,5μm absorption of SF6 in the atmospheric window is not
possible. It is necessary to use another strategy, gathering information in the far
and mid infrared regions on initial and final states to recompute the relevant total
absorption.
Here, we present new results of an analysis of spectra recorded at the AILES beam line at
the SOLEIL Synchrotron facility. For these measurements, we used a IFS125HR
interferometer in the 100 - 3200 cm-1 range, coupled to a cryogenic multiple pass cell [1].
The optical path length was adjusted to 93m; the SF6 sample was cooled down to 153 K. We
could record 17 rovibrational bands of SF6 in this region with a resolution of 0.0025 cm-1.
These results allowed us to perform the detailed analysis of several bands. Adding to previous
knowledge on ν3, ν2, 2ν3 and new results on 3ν3, 2ν1 + ν3, ν1 + ν3, ν2 + ν3, ν3 - ν2 ,
ν3 - ν1 , we developed a global fit of the ν1, ν2, ν3 parameters, thus permitting the
modelling of the ν3 + ν1 - ν1, ν3 + ν2 - ν2 hot bands. New information has also been
obtained on ν6 and ν3 + ν5 and another strategy will be detailed to model the more important
ν3 + ν5 - ν5 and ν3 + ν6 - ν6 hot band contributions. Including these new parameters in
the XTDS model [2], we substantially improved the previous global fit [3] of SF6
parameters.
[1] F. Kwabia Tchana, F. Willaert, X. Landsheere, J.- M. Flaud, L. Lago, M.
Chapuis, P. Roy, L. Manceron. A new, low temperature long-pass cell for mid-IR
to THz Spectroscopy and Synchrotron Radiation Use. Rev. Sci. Inst. 84, 093101,
(2013).
[2] C. Wenger, V. Boudon, M. Rotger, M. Sanzharov, and J.-P. Champion, ”XTDS and
SPVIEW: Graphical tools for Analysis and Simulation of High Resolution Molecular
Spectra”, J. Mol. Spectrosc. 251, 102 (2008).
[3] M. Faye, A. Le Ven, V. Boudon, L. Manceron, P. Asselin, P. Soulard, F. Kwabia
Tchana, P. Roy, High-Resolution spectroscopy of difference and combination bands of SF6 to
elucidate the ν3 + ν1 - ν1 and ν3+ ν2 - ν2hot band structures in the ν3 region, Mol. Phys.
112, 909059 (2014). |
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