The electronic structure of hydrated H3O+ and OH- is probed in a water 
jet by photoelectron spectroscopy employing 100 eV
photons. The first ionization potential for OH- at 9.2 eV and 
the second ionization potential for H3O+ at 20 eV are resolved corresponding
to the removal of an electron from the 2p. highest occupied molecular 
orbital and from the 1e orbital, respectively. These assignments are
supported by present computational results based on a 
combination of molecular dynamics and ab initio calculations.