PHOTOELECTRON-SPECTROSCOPY OF THE LINEAR (A2A1)3PB2 1B2 RYDBERG STATE OF WATER

Photoelectron spectra are reported for two-photon-resonant, three-photon ionization via several vibrational levels of the linear (A2A1)3pb2 1B2 Rydberg state of H2O and D2O. In the dominant photoionization pathway, the ejection of the Rydberg electron occurs with no change in the electronic or vibrational state of the ion core, providing direct confirmation of the vibrational numbering of the 1B2 state proposed by Abramson et al. Photoionization accompanied by excitation of the symmetric stretch in the resulting ion is also observed, reflecting the difference in bond lengths between the 1B2 Rydberg state and the A2A1 ionic state.