Solvation Dynamics in Ni+(H2O) n Clusters Probed with Infrared Spectroscopy

• Published in: Journal of the American Chemical Society Vol. 127; no. 47; pp. 16599 - 16610
• Main Authors: Walters, Richard S, Pillai, E. Dinesh, Duncan, Michael A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 30.11.2005
• Subjects: Atomic and molecular clusters; Atomic and molecular physics; Diffuse spectra; predissociation, photodissociation; Exact sciences and technology; Molecular properties and interactions with photons; Photon interactions with molecules; Physics; Stability and fragmentation of clusters; Studies of special atoms, molecules and their ions; clusters; Infrared spectroscopy; Nickel Complexes; Theoretical study; Complex cluster; Fragmentation pattern; Photodissociation; Experimental study; Dissociation energy; Time of flight mass spectroscopy; Transition elements Complexes; Vibrational analysis; Hydrogen bonds; Aqua complex; Vibrational modes; Density functional method
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0542587

Infrared photodissociation spectroscopy is reported for mass-selected Ni+(H2O) n complexes in the O−H stretching region up to cluster sizes of n = 25. These clusters fragment by the loss of one or more intact water molecules, and their excitation spectra show distinct bands in the region of the symmetric and asymmetric stretches of water. The first evidence for hydrogen bonding, indicated by a broad band strongly 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 stretch develops into a closely spaced doublet near 3700 cm-1. The data indicate that essentially all of the water molecules are in a hydrogen-bonded network by the size of n = 10. However, there is no evidence for the formation of clathrate structures seen recently via IR spectroscopy of protonated water clusters.