Absorption Cross Sections and Self-Reaction Kinetics of the IO Radical

Rate coefficients for the IO self-reaction, IO + IO → products (4), were determined over the range 250−320 K and were found to be independent of temperature with an average value of (9.9 ± 1.5) × 10-11 cm3 molecule-1 s-1. Absorption cross sections for the IO radical were measured between 340 and 480 nm. The absorption cross section at the peak of the (4,0) band was determined as a function of temperature. The cross section is essentially independent of temperature with an average value between 373 and 203 K of (3.6 ± 0.5) × 10-17 cm2 molecule-1. Comparison with previous measurements and a discussion of the atmospheric implications of these results are also presented.