The ionic states of iodobenzene studied by photoionization andab initioconfiguration interaction and DFT computations (original) (raw)

New valence electron photoelectron spectra of iodobenzene obtained using synchrotron radiation have been recorded. Ionization energies (IE) determined using multiconfiguration SCF calculations (MCSCF) procedures confirmed the adiabatic IE order as: X 2 B 1 < A 2 A 2 < B 2 B 2 < C 2 B 1. Although it is convenient to retain C 2v labelling, there is evidence that minor distortion to C S symmetry occurs at the MCSCF level for the C state. The fifth ionization process shown to be D 2 A 1 , exhibits dissociation to C 6 H 5 + + I, both in the experimental and theoretical studies. The calculated Franck-Condon vibrational spectral envelopes, including hot band contributions, for the first four ionic states reproduce the observed peak positions and intensities with reasonable accuracy. In order to simulate the