The UV-visible absorption cross-sections of IONO2
1Centre for Atmospheric Science, Chemistry Department, University of Cambridge, UK
*present address: Chemistry Department, University College London, UK
Abstract. The UV-visible absorption spectrum of gaseous IONO2 has been measured over the wavelength range 245--415 nm using the technique of laser photolysis with time-resolved UV-visible absorption spectroscopy. IONO2 was produced in situ in the gas phase by laser flash photolysis of NO2/CF3I/N2 mixtures. Post flash spectra were deconvolved to remove contributions to the observed absorption from other reactant and product species. The resulting spectrum attributed to IONO2 consists of several overlapping broad absorption bands. Assuming a quantum yield of unity for IONO2 photolysis, model calculations show that during sunlit hours at noon, 53° N, the first order solar photolysis rate coefficient (J value) for IONO2 is 4.0 x 10-2 s-1.
Mössinger, J. C., Rowley, D. M., and Cox, R. A.: The UV-visible absorption cross-sections of IONO2, Atmos. Chem. Phys., 2, 227-234, doi:10.5194/acp-2-227-2002, 2002.