PHOTODISSOCIATION OF CH2(1 B-3(1)) THROUGH THE COUPLED 2-A'' AND 3-A'' STATES - QUANTITATIVE BRANCHING RATIOS FOR THE PRODUCTION OF CH-2(H AND C+H)

Quantitative results on photodissociation of CH2((X) over tilde B-3(1) ) through the coupled 2A '' and 3 A '' states are presented. A three-d imensional, hybrid time-dependent quantum dynamical method was used, e mploying diabatic potential energy surfaces taken from ab initio calcu lations. In agreement with experiment and recent approximate dynamical calculations, a small product fraction (2.7%) was computed for the CH (A(2) Delta) + H channel. The dissociation proceeds mostly on an A(2)- like diabatic surface, into CH(a (4) Sigma(-)) + H (93.3%) and C(P-3) + H-2 (4.0%). Model calculations show that the initial motion on the ' bright' B-1-like surface biases the outcome of the dissociation in fav our of CH + H. (C) 1997 Elsevier Science B.V.