Photodissociation of CH2(13B1) through the coupled 2 A″ and 3 A″ states: quantitative branching ratios for the production of CH + H and C + H2

Quantitative results on photodissociation of CH2(X̃ 3B1) through the coupled 2 A″ and 3 A″ states are presented. A three-dimensional, hybrid time-dependent quantum dynamical method was used, employing diabatic potential energy surfaces taken from ab initio calculations. In agreement with experiment and recent approximate dynamical calculations, a small product fraction (2.7%) was computed for the CH(A2Δ) + H channel. The dissociation proceeds mostly on an A2-like diabatic surface, into CH (a 4Σ−) + H (93.3%) and C(3P) + H2 (4.0%). Model calculations show that the initial motion on the ‘bright’ B1-like surface biases the outcome of the dissociation in favour of CH + H.