Transient solvent dynamics and incoherent control of photodissociation pathways in I2− cluster ions

Detailed time-resolved photodissociation and caging dynamics in clusters are studied using I2−(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, I2−(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.