Knowledge Bank

Infrared photodissociation spectra of mass-selected $Ni+(H2O)n$ clusters are reported for $n=3-25$ complexes. The clusters fragment by the loss of one or more intact water molecules and their spectra show distinct bands in the region of the symmetric and asymmetric stretches of water $(3657cm-1,3756cm-1)$. A broad feature appears to the red of the O-H region due to hydrogen bonding at a specific cluster size $(n=4)$, indicating the onset of solvation. At larger cluster sizes, the red-shifted feature becomes more dominant and the symmetric O-H stretch loses its intensity until it is not observed at all. The data indicate that as cluster size increases, the water molecules are included in the hydrogen-bonded network and beginning with $Ni+(H2O)10$, the complexes resemble water clusters contaminated with a single metal atom.