Spectroscopic and Photochemical Perturbations of Weak Interactions on Electronic Surfaces of Methyl Iodide

Spectroscopic methods in concert with molecular-beam techniques can be used to study t h e effects of intermolecular interactions on reactive potential-energy surfaces. For these studies, w e employ photoreactive molecules 'embedded' in small clusters. Spectroscopic and photochemical studies of isolated and clustered methyl iodide are described. The following effects are presented and discussed : intensity enhancement of forbidden electronic transitions by weak intermolecular interactions; predissociation dynamics on potential-energy surfaces perturbed by weak intermolecular interactions; the effect of weak van der Waals bonds on t h e chemistry of strong, covalent, bonds. Small clusters of methyl iodide are shown to be ideal media for studying t h e perturbing effect of t h e environment on the reactive potential-energy surfaces of this molecule.