A computational investigation of the atmospheric reaction CH3O2Â +Â ClO

The computational characterization of the reaction between methylperoxy radicals and ClO is reinvestigated. The calculations suggest a plausible mechanism for the description of the two important channels observed experimentally, leading to CH3O + ClOO (1a) and CH3OCl + O2 (1b) products. More specifically, the proper reevaluation of the exothermicity of channel (1a) using spin-restricted methods, describes satisfactorily the experimental evidence about the significance of this channel as the most important pathway. The methyl hypochlorite production, channel (1b), is also shown to be significant and thermodynamically possible through either the singlet or the triplet surface. Finally, the channel CH2O + HOOCl (1e) is also investigated and found to be thermodynamically accessible, with HOOCl product readily dissociating into HCl and O2.