title: Interpretation of the photoelectron, ultraviolet, and vacuum ultraviolet photoabsorption spectra of bromobenzene by ab initio configuration interaction and DFT computations.
abstract: New photoelectron, ultraviolet (UV), and vacuum UV (VUV) spectra have been obtained for bromobenzene by synchrotron study with higher sensitivity and resolution than previous work. This, together with use of ab initio calculations with both configuration interaction and time dependent density functional theoretical methods, has led to major advances in interpretation. The VUV spectrum has led to identification of a considerable number of Rydberg states for the first time. The Franck-Condon (FC) analyses including both hot and cold bands lead to identification of the vibrational structure of both ionic and electronically excited states including two Rydberg states. The UV onset has been interpreted in some detail, and an interpretation based on the superposition of FC and Herzberg-Teller contributions has been performed. In a similar way, the 6 eV absorption band which is poorly resolved is analysed in terms of the presence of two ππ* states of (1)A1 (higher oscillator strength) and (1)B2 (lower oscillator strength) symmetries, respectively. The detailed analysis of the vibrational structure of the 2(2)B1 ionic state is particularly challenging, and the best interpretation is based on equation-of-motion-coupled cluster with singles and doubles computations. A number of equilibrium structures of the ionic and singlet excited states show that the molecular structure is less subject to variation than corresponding studies for iodobenzene. The equilibrium structures of the 3b13s and 6b23s (valence shell numbering) Rydberg states have been obtained and compared with the corresponding ionic limit structures.
authors.affiliation: School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Palmer
authors.affiliation: School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom.
authors.forename: Trevor
authors.initials: T
authors.lastname: Ridley
authors.affiliation: ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
authors.forename: Søren Vrønning
authors.initials: SV
authors.lastname: Hoffmann
authors.affiliation: ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
authors.forename: Nykola C
authors.initials: NC
authors.lastname: Jones
authors.affiliation: CNR-IMIP, Montelibretti, c/o Laboratorio Elettra, Trieste, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Coreno
authors.affiliation: CNR-IOM Laboratorio TASC, Trieste, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: de Simone
authors.affiliation: CNR-IOM Laboratorio TASC, Trieste, Italy.
authors.forename: Cesare
authors.initials: C
authors.lastname: Grazioli
authors.affiliation: Department of Physics and Astronomy, University of Uppsala, Uppsala, Sweden.
authors.forename: Teng
authors.initials: T
authors.lastname: Zhang
authors.affiliation: National Research Council ICCOM-CNR, UOS di Pisa, Via G. Moruzzi 1, I-56124 Pisa, Italy.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Biczysko
authors.affiliation: Scuola Normale Superiore, Piazza Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Baiardi
authors.affiliation: Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, USA.
authors.forename: Kirk
authors.initials: K
authors.lastname: Peterson