STRONG THERMAL NONEQUILIBRIUM IN HYPERSONIC CO AND CH4 PROBED BY CRDS

Boudon, Vincent

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https://hdl.handle.net/2142/79070 Copy

Description

Title

STRONG THERMAL NONEQUILIBRIUM IN HYPERSONIC CO AND CH4 PROBED BY CRDS

Author(s)

Boudon, Vincent

Contributor(s)

• Kassi, Samir
• Rey, Michael
• Georges, Robert
• Suas-David, Nicolas
• Louviot, Maud

Issue Date

25-Jun-15

Keyword(s)

Instrument/Technique Demonstration

Date of Ingest

2016-01-05T20:05:41Z

Abstract

A new experimental set-up coupling a High Enthalpy Source (HES) reaching 2000~K to a cw Cavity Ring-Down Spectrometer has been developed to investigate rotationnally cold hot bands of polyatomic molecules in the $[1.5,1.7]$~$mu$m region. The rotational and vibrational molecular degrees of freedom are strongly decoupled in the hypersonic expansion produced by the HES and probed by Cavity Ring-Down Spectroscopy. Carbon monoxide has been used as a first test molecule to validate the experimental approach. Its expansion in argon led to rotational and vibrational temperatures of $6.7pm 0.8$~K and $2006pm 476$~K, respectively. The Tetradecad polyad of methane ($1.67$~$mu$m) was investigated under similar conditions leading to rotational and vibrational temperatures of $13pm 5$~K and $750pm 100$~K, respectively. The rotationally cold structure of the spectra reveals many hot bands involving highly excited vibrational states of methane.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Genre of Resource

Conference Paper / Presentation

Language

English

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http://hdl.handle.net/2142/79070

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