Journal of the American Chemical Society, Vol.116, No.13, 5880-5886, 1994
Vibrational Spectroscopy of the Microsolvated Phenol Cation - Phenol-Dimethyl Ether
The hydrogen-bonded 1:1 phenol-dimethyl ether complex is studied in a skimmed supersonic jet. Two-photon, two-color resonance-enhanced multiphoton ionization (1 + 1’ REMPI) spectroscopy is used to probe the first excited singlet (S-1) state, and the spectra obtained here show that the analysis of a previously recorded laser-induced fluorescence excitation spectrum was partially erroneous. The origin of the S-1 <-- S-0 transition is now identified at 35 843.6 cm(-1); the intermolecular stretch of the S-1 state is determined (for the first time) as 141 cm(-1); other inter- and intramolecular vibrational structures are also observed and analyzed. Particular S-1 state vibrational levels are selected and then used as intermediate resonances for the zero-kinetic-energy photoelectron (ZEKE) spectroscopic studies. This technique allows the measurement of the intermolecular modes of the cationic complex. These measurements also allow the first determination of the ionization energy as 62 604 +/- 5 cm(-1) (7.7620 +/- 0.0006 eV). The intermolecular bond in the cation is over 6000 cm(-1) more stable than that in the neutral complex. A qualitative interpretation of the chemical bonding changes between this complex and other phenol-containing hydrogen-bonded complexes is presented.
Keywords:FLUORESCENCE EXCITATION-SPECTRA;KINETIC-ENERGY PHOTOELECTRON;HYDROGEN-BONDED PHENOLS;SUPERSONIC FREE JET;RESOLUTION;MOLECULES;COMPLEX;DIMER