Methyl chloride (CH3Cl) is one of the most abundant chlorine-containing molecules in the atmosphere. For this reason a recent update was performed in HITRAN for this molecule in the 0-2600 cm−1 region by Nikitin et al.1. CH3Cl has a rather strong signature at 3 μm which has been used recently by the Atmospheric Chemistry Experiment (ACE) satellite mission to produce the first study of the global distribution of methyl chloride in the upper troposphere and stratosphere 2. However it was mentioned that the CH3Cl line parameters are of very low quality in this spectral region in the HITRAN or GEISA databases 3. In this work we present a complete update of the line positions and of the (absolute) line intensities for CH3 35Cl and CH3 37Cl in the 3 μm region. At LADIR about 4000 line positions and 500 line intensities were measured for CH3 35Cl and CH3 37Cl using new high resolution FTS spectra (Bruker IFS 120) of methyl chloride. The theoretical model accounts for the interactions coupling the ν1 (l=0), ν4 (l=1), 2ν3+ν5 (l=1), 2ν5 (l=2) and 3ν6 (l=1 and l=3) vibrational states. In addition line shape studies are in progress.

{"references": ["None given"]}

Session IV-5.