Department of Chemistry, University of California, Santa Cruz, California 95064
The photodissociation of ICN in liquid chloroform on different electronic states of the A band is studied using molecular dynamics simulations. By taking into account non-adiabatic transitions to the ICN ground state and by using a simple statistical model for the reaction between the CN radical and a chloroform molecule, the competition between recombination, cage escape and hydrogen abstraction reaction with the solvent is examined. Good agreement with the cage escape results of a recent experiment by Raftery et al [(J. Chem. Phys., 101, 8572 (1994)] is found. Simulations which did not include the non-adiabatic transitions to the ground state overestimated the probability for cage escape by about a factor of two. Very fast translational relaxation of the CN fragment and very low probability for achieving a transition state configuration for the abstraction reaction are calculated. This supports the suggestion that the abstraction reaction proceeds thermally and is controlled by a structural (entropic) barrier.