Time-Resolved XAS of Strong-Field Ionized Water*

X-ray Absorption Spectroscopy (XAS) performed using next-generation x-ray free electron laser (XFEL) light sources offers insight into temporally and spatially localized electronic structure within molecules.  We apply XAS to study the multiple dissociation pathways induced by the strong-field ionization of isolated water molecules.  Combining XAS with spectral-domain ghost imaging, we observe electronic dynamics within the water cation with sub 30-fs resolution.  This measurement benchmarks the time-resolution capabilities of instruments at the high repetition rate XFEL facility, LCLS-II.