ELECTRONIC-STRUCTURE AND REACTIVITY OF MG+(H2O)N CLUSTER IONS

Electronically excited states of magnesium-water cluster ions, Mg+(H2O )n, n=1-5, are studied by photodissociation after mass selection. The observed photodissociation spectra are assigned to the P-2-S-2 type tr ansitions localized on the Mg+ ion with the aid of ab initio CI calcul ations. In addition to evaporation of water molecules, photoinduced in tracluster reaction to produce MgOH+(H2O)n is found to occur efficient ly, with pronounced size dependence. The intriguing features observed in the mass spectrum of nascent cluster ions are discussed in relation to the stepwise solvation of this reaction.