Direct Photo Double Ionization of Water and Subsequent Fragmentation

We have measured and imaged the dissociation of water in the gas phase following direct double photoionization by a 57 eV photon. The dissociation left the dication in a range of several energetically available excited states. The momenta of the resulting dication fragments and photoelectrons were measured in coincidence with Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS). The different states of the dication result in marked differences in photoelectron energies, kinetic energy release, and bond angle at the time of the fragmentation, as well as leaving the neutral oxygen fragment in one of several indirectly observed excited states.