Download presentation
Presentation is loading. Please wait.
Published byEmerald Carr Modified over 9 years ago
1
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 LOW-TEMPERATURE COLLISIONAL BROADENING IN THE FAR-INFRARED CENTRIFUGAL DISTORSION SPECTRUM OF CH 4 Vincent BOUDON 1, Jean VANDER AUWERA 2, Laurent MANCERON 3,4, Fridolin KWABIA TCHANA 5, Tony GABARD 1, Badr AMYAY 1, Mbaye FAYE 3 1 Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, Univ. Bourgogne Franche-Comté / CNRS 2 Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles 3 AILES Beamline, SOLEIL Synchrotron 4 Laboratoire MONARIS, UMR 8233, Université Pierre et Marie Curie / CNRS 5 LISA, UMR 7583, Université Paris-Est Créteil et Université Paris-Diderot / CNRS
2
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Context and method of this study Methane (CH 4 ) in Titan’s stratosphere measured in the far-infrared First high-resolution spectrum at SOLEIL V. Boudon et al., JQSRT 111, 1117 (2010) Self- and nitrogen- broadening measured at room temperature M. Sanzharov et al., JQSRT 113, 1874 (2012) Image Credit: NASA/JPL/Space Science Institute – PIA06230
3
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Example: Herschel / PACS observation of Titan Spectrum: Courtesy Dr. Miriam Rengel
4
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 I. Experimental setup
5
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 AILES beamline at SOLEIL High Resolution Absorption Spectroscopy in the Far-IR Synchrotron beam entrance Interferometer Multipass cell Bolometer detectors Maximum spectral resolution = 0.001 cm -1 Spectral range= 7-1000 cm -1
6
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Coolable long-path gas cell Adapted optics for long path (up to 150 m) Four compartment chamber Sample gas Convection-cooling gas (He) Liquid Nitrogen reservoir Insulating vacuum 1m Accurate far infrared high resolution spectra of diluted gas samples and mixture at temperatures : 400 – 90K F. Kwabia Tchana et al., Rev. Sci. Instrum. 84, 093101 (2013)
7
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 II. Experimental results
8
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Pure CH 4 overview (transmission) R(9) R(8)R(7)R(6)R(5)R(4)R(10) R(11) R(12)
9
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Overview under different conditions (absorbance)
10
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 R(6) and R(7) clusters
11
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 R(8) and R(9) clusters
12
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 R(9) cluster
13
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Preliminary simulations for pure CH 4
14
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 III. Broadening coefficients
15
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Measured self-broadening coefficients Very preliminary! !
16
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Measured N 2 -broadening coefficients Very preliminary! !
17
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Calculation at 120 K Very preliminary! !
18
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Calculation at 160 K Very preliminary! !
19
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 IV. Conclusion and perspectives
20
70 th International Symposium on Molecular Spectroscopy / Champaign-Urbana, Illinois, USA, June 22–26, 2015 Conclusions First line broadening measurements at low-temperature in the far infrared Pure CH 4 and various CH 4 /N 2 mixings Preliminary measurements of self- and nitrogen-broadening coefficients Preliminary semi-classical calculations of self- and nitrogen-broadening coefficients Perspectives for CH 4 Temperature dependence of broadening coefficients Semi-classical calculations Improved databases for planetary applications
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.