Water forms hydrogen-bonded networks that are perturbed significantly by the presence of solute molecules, even when the solute is an aromatic molecule without traditional hydrogen-bonding sites. This talk will present infrared spectra of aromatic-(H2O)n clusters in the OH stretch region that report sensitively on the H-bonded networks and the perturbations imposed on them by the aromatic solute. In small solute-(H2O)n clusters with n=1,2, the OH stretch infrared spectra display unusual combination bands that signal the presence of large-amplitude motions. In larger clusters with strong H-bonds, some of the OH stretch fundamentals are shifted into resonance with the overtone of the OH bend, producing a different kind of perturbation. Working in collaboration with the Sibert group at UW-Madison, we have developed a local-mode based theoretical model that accounts for the stretch-bend Fermi resonance and provides new insight to the perturbations imposed on the networks by the aromatic molecule.

Attaching water clusters to aromatic solutes: Spectroscopic signatures of large-amplitude motions and Fermi resonance in the OH stretch region

251st National Meeting (2016)

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