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 contr ast to metastable (unimolecular) decay where loss of C6H6 is the domin ant 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 partitionin g 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 sho w that SF6 .(C6H6)(14)(+) may adopt a structure that is more symmetric than those of its immediate neighbors.