ZERO-KINETIC-ENERGY PHOTOELECTRON-SPECTROSCOPY OF THE HYDROGEN-BONDEDPHENOL-WATER COMPLEX

Two-photon, two-color (1+1') zero-kinetic-energy (ZEKE) photoelectron spectra are presented for the 1:1 phenol-water complex, a prototype sy stem for hydrogen bonding between an aromatic molecule and a simple so lvent. ZEKE spectra via different (intermolecular) vibrational interme diate S, levels of the fully protonated complex (C6H5OD-D2O, h(3)) as well as the ZEKE spectrum via the vibrationless S-1 state of the three fold deuterated complex (C6H5OD-D2O, d(3)) have been recorded. The spe ctra are rich in structure, which is mainly attributable to intermolec ular vibrations of the ionic complex. Progressions of the intermolecul ar stretch vibration (240 cm(-1)) in combination with different interm olecular and intramolecular vibrational levels are the dominant featur e of all ZEKE spectra obtained and indicate a large change in the comp lex geometry along the hydrogen-bond coordinate on ionization. Compari son between the spectrum of the d(3) complex and the spectra via diffe rent intermediate intermolecular levels of the h(3) complex has allowe d a more detailed analysis of the intermolecular features compared to previously reported results. Finally, the vibrational assignments obta ined are compared with ab initio results for the phenol-water cation r eported in the following paper in this issue.