Transient solvent dynamics and incoherent control of photodissociation pathways in I-2(-) cluster ions

摘要

Detailed time-resolved photodissociation and caging dynamics in clusters are studied using I-2(-)(OCS)(11) as a model system. We report new observations of product channel-dependent properties of nuclear coherence in the dissociated chromophore, reflecting complex dynamics of the solvent cage. The coherence feature is most pronounced in the caged two-photon channels and its relative amplitude increases with the product size. Shorter delays, on the time scale of coherent I...I- motion, favor larger products, allowing for incoherent control of two-photon dissociation pathways by appropriately timing the two laser pulses. As an example of such control, I-2(-) (OCS)(2) is produced most effectively by a limited set of pump-probe excitations at short delays. We emphasize generality of these results that relate to caging dynamics in any cluster ions. (C) 1998 American Institute of Physics. [References: 54]