Evidence for the dominance of collision-induced intersystem crossing in collisions of 1CH2 with O2 and a determination of the H atom yields from 3CH2+O2, using time-resolved detection of H formation by vuvLIF

The formation of H atoms, following pulsed generation of CH2 a1A1 in the presence of O2, has been monitored by vacuum ultraviolet laser-induced fluorescence. The rise time of H is compatible with its production from the reaction of CH2X3B1+O2, with the interaction between the singlet and O2 leading exclusively to the formation of the triplet state by collision-induced intersystem crossing. A comparison of the intensities of the H atom signal from reaction of 1CH2 with H2 and of 1CH2 with O2 gives a yield of H from 3CH2+O2 of 0.8±0.2.