Recent studies of state-to-state vibrational predissociation (VP) dynamics of small hydrogen bonded clusters will be described, with emphasis placed on energy flow and bond breaking in small networks. Photofragment spectroscopy and ion imaging are exploited to interrogate state-specific energy flow patterns in predissociation of vibrationally excited hydrogen-bonded dimers, and ring trimers and tetramers. Bond dissociation energies of water dimers and trimers, as well as those of the HCl trimer and mixed water-HCl clusters are determined. Measured product energy distributions from the VP of these complexes are compared to theoretical models, and insights into mechanisms are obtained from the quasi-classical trajectory calculations of Bowman and coworkers. The prototype for pairwise interactions is the water dimer, while non-pairwise (cooperative) interactions are important in the small networks, such as the cyclic trimers of water and HCl, and these can be determined quantitatively by the imaging experiments. Experiments on complexes of HCl with water, which provide a way to explore incipient acid ionization, will be described as well. The floppy nature of the clusters influences energy transfer and hydrogen bond breaking mechanisms. The research was supported by the US National Science Foundation.

Imaging bond breaking and vibrational energy transfer in hydrogen-bonded clusters

251st National Meeting (2016)

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