New Applications of Ionization and Fluorescence Techniques for Detecting and Characterization of Open-Shell Organometallics in the Gas Phase.

摘要

Recent advances are discussed in the development of electronic spectroscopic probes for the study of excited-state structure and photodissociation dynamics of gas-phase organometallics. Because of the short time - scale for intermolecular energy transfer within van der Waals clusters, the UV photodissociation dynamics of cluster-bound transition metal carbonyls differs considerably from the photodissociation dynamics of the naked species in the gas phase. It is therefore possible to employ multiphoton ionization to produce cluster-bound metal carbonyl photoions in high yield. Resonant photoionization (accomplished with tunable lasers) and mass-resolved detection allow one to probe the excited states of both closed-shell and open-shell neutral organometallics. Finally, a time-resolved two-laser technique employing fluorescent detection of atomic photoproducts is described. This technique allows one to study photodissociation dynamics of organometallics with a temporal resolution competitive with the fastest transient absorption techniques, and a level of sensitivity which is far superior.