A.K. Luong, T.G. Clements, M.S. Resat and R.E. Continetti, "Energetics and dissociative photodetachment dynamics of superoxide-water clusters: O2-(H2O)n, n=1-6.", J. Chem. Phys. 114, 3449-3455 (2001).
The dissociative photodetachment of O2-(H2O)n=1-6 was studied at 388 and 258 nm using photoelectron-multiple-photofragment coincidence spectroscopy. Photoelectron spectra for the series indicate a significant change in the energetics of sequential solvation beyond the fourth water of hydration. Photoelectron-photofragment kinetic energy correlation spectra were also obtained for O2-(H2O)1-2, permitting a determination of the first and second energies of hydration for O2- to be 0.85 +/-0.05 and 0.70 +/-0.05 eV, respectively. The correlation spectra show that the peak photofragment kinetic energy release in the dissociative photodetachment of O2-(H2O) and O2-(H2O)2 are 0.12 and 0.25 eV, respectively, independent of the photon and photoelectron kinetic energies. The molecular frame differential cross section for the three-body dissociative photodetachment: O2-(H2O)2 + hv -->O2 + 2H2O + e- is also reported. The observed partitioning of momentum is consistent with either a sequential dissociation or dissociation from a range of initial geometries.