F. KWABIA TCHANA, N. LACOME, Université Pierre et Marie Curie-Paris 6; CNRS; Laboratoire de Dynamique, Interactions et Réactivité, UMR 7075, Case Courrier 49, 4 Place Jussieu, 75252 Paris Cedex 05, France; A. PERRIN, Laboratoire Inter Universitaire des Systèmes Atmosphériques (LISA), CNRS, Universités Paris 12 et 7, 61 Avenue du Général de Gaulle, 94010 Créteil Cedex, France.
Formaldehyde (H2CO) is detected in the earth's troposphere by infrared techniques in the 3.5 and 5.7-µm regions. Recent measurements produced line positions and relative line intensities\footnoteA.~Perrin, F.~Keller, and J.-M.~Flaud, J.~Mol.~Spectrosc. , \textbf221, (2003) 192. A.~Perrin, A.~Valentin, and L.~Daumont, J.~Mol.~Struct. , \textbf780-781, (2006) 28. and also IR\LeftrightarrowUV line intensity intercomparisons . For atmospheric retrievals absolute intensities and line broadening parameters are needed. For that, new Fourier transform spectra were recorded at high resolution (0.0035~cm-1) at LADIR in the 1600-3000~cm-1 spectral region. Low pressures (up to 0.5 torr) of H2CO were generated by warming paraformaldehyde. An appropriate monitoring of the heating temperature (~ 40\circ C) avoided any polymerization and allowed to obtained a stable pressure of pure H2CO (98 \pm 1%). In this way accurate line positions and absolute intensities of H2CO were measured and theoretical modelled in the 3.5 and 5.7-µm regions leading also to an intercomparison of intensities between the two spectral regions. The determination of self- and N2-broadening coefficients is in progress.