UV absorption cross sections for SO3

Room temperature gas phase absorption cross sections for SO, have been measured over the wavelength range 195 to 330 nm using a diode array spectrometer. The SO, spectrum is continuous with weak diffuse vibrational band structure in the 225 to 295 nm region. Atmospheric photolysis rate calculations show that photolysis of SO, in the 190 to 230 nm actinic window is important in determining the sulfur partitioning in the upper stratosphere.