title: The ionic states of iodobenzene studied by photoionization and ab initio configuration interaction and DFT computations.
abstract: New valence electron photoelectron spectra of iodobenzene obtained using synchrotron radiation have been recorded. Ionization energies (IEs) determined using multi-configuration SCF calculation (MCSCF) procedures confirmed the adiabatic IE order as: X(2)B1<A(2)A2<B(2)B2<C(2)B1. Although it is convenient to retain C2v labelling, there is an evidence that minor distortion to CS symmetry occurs at the MCSCF level for the C state. The fifth ionization process shown to be D(2)A1 exhibits dissociation to C6H5 (+) + 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 observed spectra, different bandwidths are required for different states. The increase in the required bandwidths for the A(2)A2 and B(2)B2 states is attributed to internal conversion to lower-lying states. The presence of relatively high intensity sequence bands leads to asymmetry of each of the X(2)B1 state bands.
authors: School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom.
authors: Michael H
authors: MH
authors: Palmer
authors: School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom.
authors: Trevor
authors: T
authors: Ridley
authors: ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
authors: Søren Vrønning
authors: SV
authors: Hoffmann
authors: ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
authors: Nykola C
authors: NC
authors: Jones
authors: CNR-IMIP, Montelibretti, c/o Laboratorio Elettra, Trieste, Italy.
authors: Marcello
authors: M
authors: Coreno
authors: CNR-IOM Laboratorio TASC, Trieste, Italy.
authors: Monica
authors: M
authors: de Simone
authors: CNR-IOM Laboratorio TASC, Trieste, Italy.
authors: Cesare
authors: C
authors: Grazioli
authors: National Research Council ICCOM-CNR, UOS di Pisa, Via G. Moruzzi 1, I-56124 Pisa, Italy.
authors: Malgorzata
authors: M
authors: Biczysko
authors: Scuola Normale Superiore, Piazza Cavalieri 7, 56126 Pisa, Italy.
authors: Alberto
authors: A
authors: Baiardi