High resolution study of the ν₅ + ν₁₂ band of C₂H₄

Abstract

The combination band ν₅ + ν₁₂ of ethylene, C₂H₄, has been recorded for the first time with a high resolution Fourier transform spectrometer Bruker IFS 125HR. Assignments of transitions and preliminary rotational analysis are made. Two models (Hamiltonian of the isolated vibrational state and Hamiltonian that takes into account resonance interactions) are used. Influence of the local resonance interactions on the parameters and reproduction power of the models is discussed.

Keywords:

• ethylene
• high-resolution spectra
• spectroscopic parameters

Acknowledgements

We enjoyed fruitful discussions with Dr. Yu. Ponomarev. Part of the work benefited from the joint PICS grant of CNRS (France) and RFBR (Russia), 4221N0000211752a; from the grant of the President of Russian Federation, SS-3400.2010.2; from the Russian Science and Innovations Federal Agency under contract No. 02.740.11.0238, and from the project No. 9.4 of the Basic Research of the Russian Academy of Sciences.

Notes

1. In Table 3 characters of irreducible representations and nomenclature of the vibrational coordinates correspond to the notations of axis, x′, y′, and z′, from 7. At the same time, belonging of the operators, J _α and/or k _zα, to one or another irreducible representation of the D_2h group corresponds to such an orientation of the coordinate axis, x, y, and z, in the C₂H₄ molecule that provides a validity of the A-reduction and I ^r -representation of a vibrational–rotational Hamiltonian.