Crossed beams and theoretical studies of the O(³P)+CH₄→H+OCH₃ reaction excitation function

A joint experimental and theoretical study of a reaction in which the excitation function measured in a crossed-beams experiment is compared with direct dynamics quasiclassical trajectory results is presented. Based on this comparison, it is found that the shape of the experimental excitation function can only be reproduced when the two first triplet surface are included in the calculations. Intersystem crossings between triplet and singlet surfaces are shown to occur at energies substantially below the reaction barrier.