Solvation and chemical reaction of sodium in water clusters

Na-m(H2O)(n) Clusters (n = 1...200, m = 1...50) are formed in a recently build pick-up arrangement. Preformed water clusters traverse a sodium oven, where sodium atoms are picked up. At low sodium vapour pressure (< 1 x 10(-4) mbar) pure Na(H2O)(n) clusters are observed in the mass spectra. At high sodium vapour pressure (> 1 x 10(-3) mbar) the water cluster pick up more than 50 Na atoms and reaction products Na(NaOH)(n) (n = 2,4...50) dominate the mass spectra. The even number of NaOH units in the products indicate that also in a finite cluster the reaction occurs in pairs as in the macroscopic reaction.