HR: 0800h
AN: P21A-0226    [Abstracts]
TI: Sulphur Dioxide: High Resolution Ultra-Violet Photoabsorption Cross Section Measurements at 200K.
AU: * Blackie, D
EM: douglas.blackie01@imperial.ac.uk
AF: Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
AU: Blackwell-Whitehead, R
AF: Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
AU: Stark, G
AF: Wellesley College, 106 Central Street, Wellesley, MA 02481, United States
AU: Pickering, J C
AF: Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
AU: Rufus, J
AF: Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
AU: Thorne, A
AF: Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
AU: Smith, P L
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
AB: Sulphur Dioxide plays an important role not only within the Earth's atmosphere but also within the complex chemistry of both the upper atmosphere of Venus and the volcanically active Jovian moon Io. The lack of high resolution laboratory studies has prevented the full, accurate determination of absorption cross sections which are the basis for reliable photochemical models. High resolution laboratory measurements of SO₂ are essential to resolve the complex SO₂ spectrum and yield accurate photoabsorption cross sections. Using the Imperial College UV Fourier Transform Spectrometer new high resolution (λ/δλ ~ 450,000) measurements have been recorded over a range of temperatures and pressures. As part of an on-going series of measurements, current laboratory work focused on photoabsorption cross sections of SO₂ at 200K across the wavelength range 220 → 325 nm. These measurements not only compliment previous room temperature measurements obtained at Imperial College in the 190 → 220 nm and 220 → 328 nm ranges (Stark et al., JGR Planets 104, 16, 585 (1999) and Rufus et al.,( JGR Planets 108, 2, 5 (2003)), but also coincide with the wavelength regions being recorded by the Venus Express mission through the UV-IR spectrometer SPICAV (ESA-SCI(2001)6). Our new measurements will allow accurate analysis of the chemical processes in the upper atmosphere of Venus. These absorption cross section measurements are the first to be acquired at this resolution, temperature and pressure. Results will be presented. This work was supported in part by NASA Grant NNG05GA03G, PPARC (UK), and the Leverhulme Trust.
DE: 9805 Instruments useful in three or more fields
DE: 9820 Techniques applicable in three or more fields
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting