A SPECTROSCOPIC STUDY OF CL2O3

The UV absorption spectrum of dichlorine trioxide, Cl2O3 has been reco rded in the wavelength range 220-340 nm and at 223 K using a recently developed flash photolysis-kinetic UV absorption spectroscopy apparatu s. Cl2O3 was generated in the reaction between ClO and OClO following the partial photolysis of OClO. The spectrum obtained is smooth, and s hows a peak at 267 nm, where sigma = 1.76 x 10-(17) cm(2) molecule(-1) (base e). Results are broadly consistent with previous determinations of the spectrum, although we report higher cross-sections in the long -wavelength tail of the absorption. The discrepancies between these an d previous measurements are discussed, together with the atmospheric i mplications of this work.