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Theoretical Study of the Fast Photodissociation Channels of the Monohalobenzenes

Liu, Y.-J.; Persson, Petter LU and Lunell, S. (2004) In The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory 108(12). p.2339-2345
Abstract
Excited state properties of fluorobenzene, chlorobenzene, bromobenzene, and iodobenzene have been investigated theoretically using multireference CASSCF and CASPT2 methods. Experimentally, chlorobenzene and bromobenzene are known to exhibit one fast dissociation channel, whereas iodobenzene exhibits two fast dissociation channels. The calculations indicate that the chlorobenzene, the bromobenzene, and the slower iodobenzene dissociation channels are due to intersystem crossings from a bound (π,π*) singlet excited state to a repulsive (n,σ*) triplet excited state. The faster iodobenzene dissociation channel is instead found to be caused by a direct dissociation of an antibonding (n,σ*) singlet excited state. The CASPT2 calculations predict... (More)
Excited state properties of fluorobenzene, chlorobenzene, bromobenzene, and iodobenzene have been investigated theoretically using multireference CASSCF and CASPT2 methods. Experimentally, chlorobenzene and bromobenzene are known to exhibit one fast dissociation channel, whereas iodobenzene exhibits two fast dissociation channels. The calculations indicate that the chlorobenzene, the bromobenzene, and the slower iodobenzene dissociation channels are due to intersystem crossings from a bound (π,π*) singlet excited state to a repulsive (n,σ*) triplet excited state. The faster iodobenzene dissociation channel is instead found to be caused by a direct dissociation of an antibonding (n,σ*) singlet excited state. The CASPT2 calculations predict that the onset of fluorobenzene photodissociation should occur around 196 nm, with a single time constant longer than 1 ns. CASSCF geometries and accurate MSCASPT2 calculated vertical excitation energies are presented for the ground state as well as the first excited singlet and triplet states of all the monohalobenzenes. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
volume
108
issue
12
pages
2339 - 2345
publisher
The American Chemical Society
external identifiers
  • scopus:1842636265
ISSN
1520-5215
DOI
10.1021/jp0379648
language
English
LU publication?
no
id
2745fd19-cb86-417f-a019-4cf30a682a52 (old id 1457785)
date added to LUP
2009-08-28 12:49:31
date last changed
2017-06-11 04:32:57
@article{2745fd19-cb86-417f-a019-4cf30a682a52,
  abstract     = {Excited state properties of fluorobenzene, chlorobenzene, bromobenzene, and iodobenzene have been investigated theoretically using multireference CASSCF and CASPT2 methods. Experimentally, chlorobenzene and bromobenzene are known to exhibit one fast dissociation channel, whereas iodobenzene exhibits two fast dissociation channels. The calculations indicate that the chlorobenzene, the bromobenzene, and the slower iodobenzene dissociation channels are due to intersystem crossings from a bound (π,π*) singlet excited state to a repulsive (n,σ*) triplet excited state. The faster iodobenzene dissociation channel is instead found to be caused by a direct dissociation of an antibonding (n,σ*) singlet excited state. The CASPT2 calculations predict that the onset of fluorobenzene photodissociation should occur around 196 nm, with a single time constant longer than 1 ns. CASSCF geometries and accurate MSCASPT2 calculated vertical excitation energies are presented for the ground state as well as the first excited singlet and triplet states of all the monohalobenzenes.},
  author       = {Liu, Y.-J. and Persson, Petter and Lunell, S.},
  issn         = {1520-5215},
  language     = {eng},
  number       = {12},
  pages        = {2339--2345},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory},
  title        = {Theoretical Study of the Fast Photodissociation Channels of the Monohalobenzenes},
  url          = {http://dx.doi.org/10.1021/jp0379648},
  volume       = {108},
  year         = {2004},
}