The high resolution infrared spectrum of ethylene in the 1800 cm-1 to 2350 cm-1 spectral region

W.J. Lafferty (1) , Jean Marie Flaud (2) , Fridolin Kwabia (2)

1 NIST - National Institute of Standards and Technology [Gaithersburg]
2 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques

Fourier transform spectra of ethylene (C2H4) have been recorded in the 1800 cm-1 to 2350 cm-1 (4.3 μm to-5.6 μm) spectral region using a Bruker IFS125 HR spectrometer at a resolution of 0.004 cm-1 leading to the observation of six vibrational bands, ν7 + ν8 , ν4 + ν8 , ν6 + ν10, ν6 + ν7, ν4 + ν6 and ν3 + ν10. The corresponding upper state ro-vibrational levels were fit using a Hamiltonian matrix accounting for numerous interactions. A satisfactory fit could be obtained using a polyad of nine interacting states {81101, 7181, 4181, 81121, 61101, 6171, 4161, 31101, 3171} among which three (81101, 81121 and 3171) are unobserved dark states. As a result a much more accurate and extended set of Hamiltonian constants were obtained than previously derived. The following band centers were determined: : ν0(ν7+ ν8) = 1888.9783(20) cm-1, ν0(ν4+ ν8) = 1958.2850(20) cm-1, ν0(ν6+ ν10) = 2047.7589(20) cm-1 , ν0(ν6+ ν7) = 2178.011(60) cm-1 , ν0(ν4+ ν6) = 2252.8026(24) cm-1 and ν0(ν3+ ν10) = 2171.2397(20) cm-1. Finally, a synthetic spectrum which couldl be useful for ethylene detection in planetary atmospheres was generated.

Mots clés: Physical Sciences

Domaines: Matière Condensée [cond-mat]

W.J. Lafferty, Jean Marie Flaud, Fridolin Kwabia. The high resolution infrared spectrum of ethylene in the 1800 cm-1 to 2350 cm-1 spectral region. Molecular Physics, 2011, 109 (21), pp.2501-2510. ⟨10.1080/00268976.2011.577040⟩. ⟨hal-00747936⟩