Lineshape analysis of the J=3←2 and J=5←4 rotational transitions of room temperature CO broadened by N2, O2, CO2 and noble gases
| Autor: | Georges Wlodarczak, J.-M. Colmont, François Rohart, Linh Nguyen |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Voigt profile
Materials science Spectrometer Atomic and Molecular Physics and Optics Linear variation Pressure range chemistry.chemical_compound symbols.namesake Laser linewidth Nuclear magnetic resonance chemistry symbols Millimeter Physical and Theoretical Chemistry Atomic physics Doppler effect Spectroscopy Carbon monoxide |
| Zdroj: | Journal of Molecular Spectroscopy. 246:86-97 |
| ISSN: | 0022-2852 |
| DOI: | 10.1016/j.jms.2007.08.003 |
| Popis: | Collisional relaxation has been considered for millimeter lines of carbon monoxide at room temperature. Accurate measurements of carbon dioxide- and rare gases-broadened widths have been performed on the J = 3 ← 2 rotational line of 12 CO by using a video-type spectrometer. Measurements of nitrogen-, oxygen-, and xenon-broadened widths of the J = 5 ← 4 rotational line of 13 CO were also carried by using a frequency-modulated spectrometer. A lineshape study performed on all the investigated binary systems provide confirmation that Voigt profile is not a suitable model to analyse experimental lines in the millimeter-waves region. On one hand, using this profile in the low pressure range, i.e. in the Doppler regime, the retrieved collisional linewidths do not follow a linear variation with the perturbing gas pressure. On the other hand, regardless of the pressure, lineshapes exhibit a narrowed profile. An accurate analysis of the pressure dependence of relaxation rates show that the Galatry profile is not appropriate and that experimental lineshapes are actually Speed Dependent Voigt profiles. Accurate broadening parameters were retrieved from this profile and compared to previous reported values and predictions calculated from the Robert–Bonamy formalism. Finally a variation of the ratio of relaxation speed dependence to broadening parameters versus relative masses of the collision partners is presented. |
| Databáze: | OpenAIRE |
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