3-DIMENSIONAL ANALYTICAL INFINITE-ORDER SUDDEN QUANTUM-THEORY FOR TRIATOMIC INDIRECT PHOTODISSOCIATION PROCESSES

Our previously developed analytical infinite order sudden (IOS) quantu m theory of triatomic photodissociation is extended to describe indire ct photodissociation processes through a real or virtual intermediate state. The theory uses the IOS approximation for the dynamics in the f inal dissociative channels and an Airy function approximation for the continuum states. These approximations enable us to evaluate the multi -dimensional non-separable transition amplitudes analytically (as one- dimensional quadratures), despite the different natural coordinates fo r the initial bound, the intermediate resonant, and the final dissocia tive states. The fragment internal energy distributions are described as a function of the initial and final quantum states and the photon e xcitation energy. The theory readily permits the evaluation of rotatio nal distributions for high values of the total angular momentum J in t he initial bound molecular state, a feature that would be very difficu lt with close-coupled methods. In paper II we apply the theory to desc ribe the photofragment yield spectrum of NOCl in the region of the T-1 (1(3)A '')<--S-0(1(1)A') transition. (C) 1997 American Institute of Ph ysics.