The High Resolution Infrared Spectrum of 34SO2 up to 4000 cm_1

The infrared spectrum of sulfur dioxide is of interest both for the earth (volcanic eruptions in particular) and planetary (Venus, Io) atmospheres. While the spectrum of the normal species, 32SO2, has been very well studied and an excellent set of molecular constants obtained, this is not the case for the rarer isotopic species, 34SO2, the abundance of which is about 4.2% of the normal species. In order to improve our knowledge of the 34SO2 spectrum we have studied a sample of SO2 enriched to 95% in 34S at high resolution (0.0019 cm_1 ) over a wavenumber region including all the fundamental bands, the relatively strong combination bands _2+_3 and _1+_3 as well as the weaker 2_3 and 2_1+_3 bands. Also the hot bands 2_2-_2, 3_2-2_2, _1+_2-_2, _2+_3-_2, _1+_2+_3-_2 were analysed. In this way, an accurate set of assigned lines was derived. The experimental energy levels were fitted leading to an accurate set of rotational constants for the (000), (010), (020), (030), (100), (001), (101), (201) vibrational states. From these constants, equilibrium rotational constants were derived and an accurate equilibrium structure determined. Finally, line intensities are being measured and preliminary results concerning this last point will be presented.Session V-5