PHOTODISSOCIATION OF MAGNESIUM-ION MOLECULE COMPLEXES IN A REFLECTRONTIME-OF-FLIGHT MASS-SPECTROMETER

Ion/molecule cluster complexes containing magnesium (e.g., Mg+-(CO2)x, Mg+-(H2O)x) are generated in a pulsed nozzle cluster source. Specific ions are size selected from the source distribution with a reflectron time-of-flight mass spectrometer for studies of their photodissociati on dynamics. Photoexcitation of these complexes near the Mg+ (2S --> 2 P) resonance line causes a variety of novel photochemistry, ranging fr om simple ligand ejection, to metal insertion, to metal-ligand charge exchange. These reactions arc first observed in the single molecule co mplexes, and they persist in larger aggregates with more extensive sol vation. Excitation spectra probe the energy dependence of the photoche mistry and they provide information on the structures of the ion/molec ule complexes.