TIME-RESOLVED AND PRODUCT ANGLE-VELOCITY MEASUREMENTS OF (CH3I)(N) CLUSTER PHOTODISSOCIATION

We present a study of the photodissociation of CH3I to CH3 + I in an isolated molecule and in clusters. In previous picosecond pump-probe studies of photodissociation in clusters, we observed very fast sequential radical chemistry. An important recurring reaction is CH3 + CH3I --> C2H6 + I. In this paper we present new measurements of the I atom anisotropy and kinetic energy distribution from cluster photodissociation and make comparisons to similar measurements in bare CH3I. Using a new photofragment imaging technique for measuring angle-velocity distributions, we measured an I atom kinetic energy distribution for cluster photodissociation that is substantially broader and of lower energy than that observed for monomer photodissociation. The angular distribution is essentially isotropic in the former case as opposed to highly anisotropic in the latter case.