| Abstract
| - Infrared photodissociation spectroscopy is reported for mass-selected Ni+(H2O)n complexes inthe O−H stretching region up to cluster sizes of n = 25. These clusters fragment by the loss of one ormore intact water molecules, and their excitation spectra show distinct bands in the region of the symmetricand asymmetric stretches of water. The first evidence for hydrogen bonding, indicated by a broad bandstrongly red-shifted from the free OH region, appears at the cluster size of n = 4. At larger cluster sizes,additional red-shifted structure evolves over a broader wavelength range in the hydrogen-bonding region.In the free OH region, the symmetric stretch gradually diminishes in intensity, while the asymmetric stretchdevelops into a closely spaced doublet near 3700 cm-1. The data indicate that essentially all of the watermolecules are in a hydrogen-bonded network by the size of n = 10. However, there is no evidence for theformation of clathrate structures seen recently via IR spectroscopy of protonated water clusters.
|
