Abstract
Photoabsorption cross sections of sulphur dioxide have been measured in the spectral region 280-320 nm for temperatures ranging from 220 to 300 K at an interval of 20 K. These measurements have been carried out with an accuracy of plus or minus 4.1% at an instrumental resolution of 0.1 nm. The cross sections obtained in the present experiment have been compared with other measurements wherever possible. The role of sulphur dioxide in the troposphere and stratosphere of the Earth is well known. The volcanic eruptions from El Chichon and Mount Pinatube in 1982 and 1991 respectively have been responsible for depositing solid and gaseous materials in the atmosphere in the form of SO sub(2) clouds. Bluth et al have shown that SO sub(2) along with other sulphur compounds acts as an aerosol precursor and exerts an effect on cloud production as well as other climatic conditions. Sulphur dioxide is also an important constituent of the atmospheres of Venus and Io. It has been found that the absorption of solar radiation in the vacuum ultra-violet and ultra-violet spectral regions is one of the dominant mechanisms for studying the chemistry of the Terrestrial and Venusian atmospheres. That is why there is a need for improved laboratory measurements of the photoabsorption cross sections of SO sub(2) in the spectral regions mentioned above. Also, these measurements should be carried out at various temperatures of planetary and atmospheric interest.