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[56.07] High resolution photoabsorption cross section measurements of SO₂ at 295 K between 220 and 328 nm

P.L. Smith, J. Rufus (Harvard-Smithsonian CfA), G. Stark (Dept. of Physics, Wellesley College), A.P. Thorne, J.C. Pickering (Blackett Laboratory, Imperial College, London)

Analysis of the UV spectrum of Io and modelling of the chemical composition of, and photochemical processes in, its atmosphere require knowledge of the photoabsorption cross section of SO₂ over a wide wavelength range at temperatures from 110 to ~500 K. Our laboratory program, which employs an ultraviolet Fourier transform spectrometer at Imperial College, London, provides such data at very high resolution. Previous photoabsorption measurements at these wavelengths have been unable to resolve the very congested SO₂ spectrum.

We report new cross section data for SO₂ at 295 K for wavelengths between 220 and 328~nm at resolving powers, \lambda/\Delta\lambda, from 90,000 to 550,000. The new work complements our earlier cross section data for SO₂ at room temperature in the 190 to 220 nm wavelength region [Stark {\em et al}., JGR Planets 104, 16,585 (1999)]. Current effort is focussed on analysis of similar data over the wavelength range 190 to 220 nm for SO₂ cooled to 160 K.

This work was supported in part by NASA Grant NAG5-9059.

The author(s) of this abstract have provided an email address for comments about the abstract: gstark@wellesley.edu

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