The UV-visible absorption cross-sections of IONO₂

J. C. Mössinger (1) , D. M. Rowley (1) , R. A. Cox (1)

1 Centre for Atmospheric Science [Cambridge, UK]

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 4.6 x 10^-2 s^-1.

Domaines: Océan, Atmosphère

J. C. Mössinger, D. M. Rowley, R. A. Cox. The UV-visible absorption cross-sections of IONO₂. Atmospheric Chemistry and Physics Discussions, 2002, 2 (3), pp.765-788. ⟨hal-00300844⟩