LASER-INDUCED INFRARED PHOTOFRAGMENTATION OF SF6(C6H6)(N)(+) CLUSTER IONS

Size-selected SF6 .(C6H6)(n)(+) cluster ions have been photoexcited in the infrared using radiation from a line-tuneable CO2 laser. In contrast to metastable (unimolecular) decay where loss of C6H6 is the dominant decay channel, photoexcitation only promotes the loss of SF6. This observation is rationalized in terms of a structure where SF6 resides on the surface of the cluster and there is no statistical partitioning of the photon's energy prior to dissociation. Further support for a surface-bound SF6 is provided by infrared absorption profiles recorded as a function of laser wavelength. These latter measurements also show that SF6 .(C6H6)(14)(+) may adopt a structure that is more symmetric than those of its immediate neighbors.