15min:

I. KLEINER, Laboratoire de Photophysique Mol\a'eculaire, Batiment 210, Universit\a'e PARIS 11, Campus d'ORSAY, 91405 ORSAY CEDEX, FRANCE; M. HEPP, R. GEORGES AND M. HERMAN, Laboratoire de Chimie Physique Mol\a'eculaire, CP160/09, Universit\a'e Libre de Bruxelles, B-1050, Belgium.

Three ranges of the infrared and near infrared absorption spectrum of CH₃CHO have been recorded using a Fourier transform interferometer, under various experimental conditions: between 1300 and 3100 cm^-1 at a resolution of 0.01 cm^-1 under jet cooled conditions, between 1400 and 3200 cm^-1 at a resolution of 0.008 cm^-1 at room temperature, and between 4000 and 8000 cm^-1 at a resolution of 0.03 cm^-1 at room temperature. We are investigating specific bands in those ranges, all presenting problems of different nature, severely limiting the analysis in each case. We are studying ₅ and ₁₂ respectively located at 1429.91 and 1435.83 cm^-1. They are two methyl bending fundamentals, with strong Coriolis interaction. We are also focusing on the aldehydic CH stretch fundamental band (₃), located around 2716 cm^-1 and known to be in Fermi-type interaction with 2₆. Eventually, we are considering the two first overtones of the aldehydic CH stretch, observed around 5320 and 7810 cm^-1, presenting a dense structure.