PHOTOIONIZATION AND PHOTODISSOCIATION STUDIES ON ALUMINUM-WATER CLUSTERS AND THEIR IONS

Clusters of aluminum atoms solvated with water molecules, Al(H2O)n, ha ve been studied by one-photon ionization and time-of-flight mass spect roscopy. Characteristic feature is observed in the photoionization mas s spectrum: The intensities of the product Al+(H2O)n ions are about on e order of magnitude larger for n less-than-or-equal-to 4 than for n g reater-than-or-equal-to 5. The ionization potentials are determined fo r n up to 4. The obtained results are discussed in connection with the recent theoretical works. The photodissociation spectroscopy has also been applied to the Al+(H2O)n ions with n = 1-10. The observed spectr a are ascribed to the transition localized on the Al+ ion on the analo gy of the results Of Mg+(H2O)n photodissociation. The dissociation dyn amics is also discussed from the fragmentation pattern with the aid of the recent theoretical work on the structure and stability of these i ons.