Kinetics of the IO Radical. 1. Reaction of IO with ClO

The rate coefficient for the IO + ClO → products (5) reaction was measured by coupling discharge flow and pulsed laser-induced fluorescence techniques. Rate coefficients were measured from 200 to 362 K by monitoring the temporal profile of IO in an excess of ClO. The rate coefficient is described by the expression: k 5 ( T ) = (5.1 ± 1.7) × 10 -12 exp[(280 ± 80)/ T ] cm 3 molecule -1 s -1 where the quoted uncertainties include estimated systematic errors. Atomic iodine was identified as a major product of reaction 5. A branching ratio of Φ = 0.14 ± 0.04 at 298 K was obtained for the sum of channels which do not produce I atoms.