ROTATIONAL-EXCITATION AS A PROBE OF PHOTOCHEMISTRY IN (HI)(N) CLUSTERS

Laser excitation in the range 280-285 nm was used to initiate chemistry in small (HI)(n) clusters formed in a supersonic expansion. The same laser pulse also probed the rotational population of HI monomers by 2 + 1 REMPI through three different excited states. An increase in the HI rotational temperature above the normally very low temperature of the molecular beam was detected and is indicative of chemistry occurring within the cluster environment. Laser intensity and stagnation pressure dependence studies were conducted to provide further insight into the chemistry. Possible mechanisms that yield product molecules with internal excitation, including H-atom exchange reactions, are discussed.