FOURIER TRANSFORM ABSORPTION SPECTROSCOPY OF C3 IN THE ν3 ANTISYMMETRIC STRETCH MODE REGION

Pirali, Olivier

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https://hdl.handle.net/2142/97093 Copy

Description

Title

FOURIER TRANSFORM ABSORPTION SPECTROSCOPY OF C3 IN THE ν3 ANTISYMMETRIC STRETCH MODE REGION

Author(s)

Pirali, Olivier

Contributor(s)

• Tokaryk, Dennis W.
• Martin-Drumel, Marie-Aline
• Vervloet, Michel

Issue Date

6/22/2017

Keyword(s)

Radicals

Abstract

The C$_3$ molecule has been detected in a variety of astrophysical objects thanks to the well-known 4050 AA~(A$^1Pi_u$--X$^1Sigma ^+ _g$) electronic transition as well as the two IR active modes of the electronic ground state: $nu_2$ ($sim$ 63.42 cm$^{-1}$) and $nu_3$ ($sim$ 2040.02 cm$^{-1}$)footnote{L. Gausset, G. Herzberg, A. Lagerqvist, B. Rosen, Astrophysical Journal, 45--81 (1965); T. F. Giesen et al., The Astrophysical Journal, 551, L181--L184 (2001); K. W. Hinkle, J. J. Keady, P. F. Bernath, Science, 241, 1319--1322 (1988)}. Previous laboratory data in the $nu_3$ region, obtained using diode laser spectroscopy and the photolysis of allene to produce C$_3$, permitted measurement of the fundamental (0,0,1)$Sigma$--(0,0,0)$Sigma$ as well as the hot bands: (0,1,1)$Pi$--(0,1,0)$Pi$; (0,2,1)$Sigma$--(0,2,0)$Sigma$; (0,2,1)$Delta$--(0,2,0)$Delta$ and provided insights on the anharmonicity of the (0,$nnu_2$,1) vibrational patternfootnote{K. Kawaguchi et al., J. Chem. Phys., 91, 1953--1957 (1989)}._x000d_ _x000d_ We have recorded the absorption spectrum of C$_3$ in the 1800--2100 cm$^{-1}$ region (at a resolution of 0.003 cm$^{-1}$) using the Bruker IFS 125 Fourier Transform spectrometer at the AILES beamline of Synchrotron SOLEIL. C$_3$ was produced in a DC discharge of methane heavily diluted in helium. The rovibrational temperature of C$_3$ produced in our discharge is noticeably higher than in Ref. [4], which allowed us to extend measurements to higher $J$ values. More interestingly, we assigned new hot bands involving higher quanta of the $nu_2$ bending states: (0,$nnu_2$,1) with $n$ ranging from 0 to 5. Despite the absence of $Q$ branches for these bands, which results in a possible ambiguous $J$-assignment of $P$ and $R$ lines, the large variety of data considered in this work, in addition to our experimental data and including observations of comet spectra, allows confident assignments.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/97093

DOI

10.15278/isms.2017.RJ09

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