Computational studies of the reactions of CH3I with H and OH

Transition states for attack by H and OH at the CH and CI bonds of CH3I have been characterized at the Gaussian-2 level of theory. The results are employed in transition state theory analyses to obtain ab initio rate constants and product branching ratios. For the H reaction the major pathway is predicted to be I-atom abstraction, while for OH attack H-atom abstraction is faster than HOI formation. The rate constants agree well with measurements at around room temperature and are extrapolated to combustion conditions. The contributions of the title reactions to the flame chemistry of CH3I are assessed.