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Non Franck-Condon effects in photoionization of molecular oxygen

Erman, Peter; Karawajczyk, Andrzej; Rachlew, Elisabeth; Rius i Riu, Jaume LU ; Stankiewicz, Marek; Yoshiki Franzén, Ken; Weider Moen, A and Veseth, Leif (2000) In Physica Scripta 62(4). p.294-300
Abstract
We present a theoretical and experimental analysis of non Franck-Condon effects in photoionization to the b 4Σg- state of O2+. Experimentally, by dispersing the synchrotron radiation induced O2+ b 4Σg- - a 4Πu fluorescence we derive the b 4Σg- state vibrational branching ratios in the excitation energy range 21–34 eV. The vibrational branching ratios reveal features in the region 21–28 eV, indicating strong non Franck-Condon effects. The experimental results have been analysed by computing ab initio the vibrational population branching ratios using a many-body perturbation method. Additionally, the autoionizing neutral states existing in this energy region have been studied. We have computed the energies of the valence states up to an... (More)
We present a theoretical and experimental analysis of non Franck-Condon effects in photoionization to the b 4Σg- state of O2+. Experimentally, by dispersing the synchrotron radiation induced O2+ b 4Σg- - a 4Πu fluorescence we derive the b 4Σg- state vibrational branching ratios in the excitation energy range 21–34 eV. The vibrational branching ratios reveal features in the region 21–28 eV, indicating strong non Franck-Condon effects. The experimental results have been analysed by computing ab initio the vibrational population branching ratios using a many-body perturbation method. Additionally, the autoionizing neutral states existing in this energy region have been studied. We have computed the energies of the valence states up to an energy of 30 eV, their transition moments for excitations from the ground state, and autoionization rates. Our calculations show, that strong non Franck-Condon effects recorded in the branching ratio spectrum (below 25 eV) are actually caused by the narrow 3σg → σu shape resonance, and its coupling to the 1πu → πg channel. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Physica Scripta
volume
62
issue
4
pages
294 - 300
publisher
Institute of Physics Publishing Ltd.
external identifiers
  • scopus:0001698514
ISSN
0031-8949
DOI
10.1238/Physica.Regular.062a00294
language
English
LU publication?
no
id
d80ec662-b480-4269-81de-5a2f9509be0b (old id 1029877)
date added to LUP
2008-02-18 12:05:56
date last changed
2017-01-01 07:36:49
@article{d80ec662-b480-4269-81de-5a2f9509be0b,
  abstract     = {We present a theoretical and experimental analysis of non Franck-Condon effects in photoionization to the b 4Σg- state of O2+. Experimentally, by dispersing the synchrotron radiation induced O2+ b 4Σg- - a 4Πu fluorescence we derive the b 4Σg- state vibrational branching ratios in the excitation energy range 21–34 eV. The vibrational branching ratios reveal features in the region 21–28 eV, indicating strong non Franck-Condon effects. The experimental results have been analysed by computing ab initio the vibrational population branching ratios using a many-body perturbation method. Additionally, the autoionizing neutral states existing in this energy region have been studied. We have computed the energies of the valence states up to an energy of 30 eV, their transition moments for excitations from the ground state, and autoionization rates. Our calculations show, that strong non Franck-Condon effects recorded in the branching ratio spectrum (below 25 eV) are actually caused by the narrow 3σg → σu shape resonance, and its coupling to the 1πu → πg channel.},
  author       = {Erman, Peter and Karawajczyk, Andrzej and Rachlew, Elisabeth and Rius i Riu, Jaume and Stankiewicz, Marek and Yoshiki Franzén, Ken and Weider Moen, A and Veseth, Leif},
  issn         = {0031-8949},
  language     = {eng},
  number       = {4},
  pages        = {294--300},
  publisher    = {Institute of Physics Publishing Ltd.},
  series       = {Physica Scripta},
  title        = {Non Franck-Condon effects in photoionization of molecular oxygen},
  url          = {http://dx.doi.org/10.1238/Physica.Regular.062a00294},
  volume       = {62},
  year         = {2000},
}