Formation of bromine chloride(3.PI.0+) in the reaction of bromine monoxide with chlorine monoxide

Observations of bromine atom yields from the reaction of BrO with ClO indicate the presence of a third product channel in addition to channels which form Br + OClO and Br + ClOO. The authors argue that this process is a four-center elimination of vibrationally excited BrCl(/sup 3/II/sub 0/sup +//) and O/sub 2/(/sup 3/..sigma../sub g//sup -/) from an internally excited singlet BrOOCl intermediate. The excited BrCl subsequently is quenched, predissociates, or fluoresces; the latter process has been observed previously in the Br/sub 2/ + OClO chain reaction system. This mechanism may commonly occur in the halogen monoxide disproportionation reactions. The implications of this new channel for kinetic measurements and models of stratospheric ozone depletion are significant.