ULTRAVIOLET PHOTOELECTRON-SPECTROSCOPY OF THE PHENIDE, BENZYL AND PHENOXIDE ANIONS, WITH ABINITIO CALCULATIONS

The 351 nm photoelectron spectra of the phenide, benzyl and phenoxide anions are reported. Information obtained for phenyl radical includes an adiabatic electron affinity (EA) of 1.096(6) eV, two vibrational modes at 600(10) and 968(15) cm-1, and an excited electronic state at less-than-or-equal-to 1.7 eV. For benzyl, the radical EA is 0.912(6) eV, a vibration appears at 514(15) cm-1, and another is possibly present at 1510(25) cm-1. Phenoxyl radical has an EA of 2.253(6) eV, exhibits a vibration at 515(15) cm-1, and possibly another at 1490(25) cm-1. The first excited state of phenoxyl radical appears at 1.06(5) eV above the ground state. Ab initio calculations using GAUSSIAN 88 are used to elicit geometries, normal modes of the active vibrations, and help confirm the presence of various vibrations. Combining our results with previous measurements we find gas-phase acidities for benzene and toluene of 399(2) kcal mol-1 and 380.5(1.5) kcal mol-1 respectively, and a hydrogen bond dissociation energy for phenol of 86.5(2) kcal mol-1.