The 2CH excitation band in C₂H₂–N₂O and 2CH+torsion combination bands in C₂H₂–N₂O and C₂H₂–CO₂

Abstract

A preliminary analysis of the 2CH excitation band in C₂H₂–N₂O in the 1.5  µm range (K. Didriche, C. Lauzin, P. Macko, M. Herman and W.J. Lafferty, Chem. Phys. Letters 469, 35 (2009).), only considering 117 low J-, and K_a - vibration-rotation lines, is significantly extended thanks to the analysis of new spectra including very regular series of lines with J/K_a up to 31/15. 1271 b-type lines were assigned. Perturbations are briefly discussed. The rotational temperature in the experiments is estimated to be 20 K and the upper state mean half-time is 1.6 ns for non perturbed levels. The previous analyses of the 2CH + torsion band in C₂H₂–N₂O and in C₂H₂–CO₂ (C. Lauzin, K. Didriche, T. Földes and M. Herman, Mol. Phys. 109, 2105 (2011).), are also extended to include 286 and 234 lines, respectively, also correcting for calibration errors. New rotational constants are obtained using a rigid rotor Hamiltonian by simultaneously fitting the ground, 2CH and 2CH + torsion states in C₂H₂–N₂O, and the latter state, only, in C₂H₂–CO₂.

Keywords:

• van der Waals complex
• overtone spectroscopy
• intermolecular vibration
• acetylene
• CRDS
• supersonic expansion

Acknowledgements

We are indebted to Drs W. Lafferty (NIST) and A. Perrin (LISA) for their help during initial steps in the analysis. This work was sponsored by the Fonds National de la Recherche Scientifique (FNRS, contracts FRFC and IISN) and the «Action de Recherches Concertées de la Communauté française de Belgique».

Notes

FRS-FNRS postdoctoral fellow.

AGACC postdoctoral fellow.

Additional information

Notes on contributors

K. Didriche

FRS-FNRS postdoctoral fellow.

T. Földes

AGACC postdoctoral fellow.