Photodissociation, Recombination, and Electron Transfer in Cluster Ions:  A Nonadiabatic Molecular Dynamics Study of I<INF>2</INF><SUP>-</SUP>(CO<INF>2</INF>)<INF>n</INF><INF></INF>

We simulate and interpret the photodissociation and recombination of I<INF>2</INF>^- embedded in CO<INF>2</INF> clusters using a Hamiltonian that accounts for the strong perturbation of the solute electronic structure by the solvent. The calculated product distributions agree well with the experimental results of Lineberger and co-workers. Excited-state dynamics are more involved than anticipated from the isolated solute potential curves. For example, dissociation does not occur from the A‘ state, and permanent recombination occurs only on the X state, despite the fact that the A state of I<INF>2</INF>^- is weakly bound. We discuss the role of the cluster environment in bringing about recombination and electronic relaxation in terms of a qualitative model inspired by the theory of electron transfer in solution.