Core localization and sigma* delocalization in the O 1s core-excited sulfur dioxide molecule.
Electron-ion-ion coincidence measurements of sulfur dioxide at discrete resonances near the O 1s ionization edge are reported. The spectra are analyzed using a model based upon molecular symmetry and on the geometry of the molecule. We find clear evidence for molecular alignment that can be ascribed to symmetry properties of the ground and core-excited states. Configuration interaction (CI) calculations indicate geometry changes in accord with the measured spectra. For the SO(2) molecule, however, we find that the localized core hole does not produce measurable evidence for valence localization, since the transition dipole moment is not parallel to a breaking sigma* O-S bond, in contrast to the case of ozone. The dissociation behavior based upon the CI calculations using symmetry-broken orbitals while fixing a localized core-hole site is found to be nearly equivalent to that using symmetry-adapted orbitals. This implies that the core-localization effect is not strong enough to localize the sigma* valence orbital.
Lindgren
Andreas
A
Department of Synchrotron Radiation Research, Institute of Physics, University of Lund, Lund, Sweden.
Kosugi
Nobuhiro
N
Gisselbrecht
Mathieu
M
Kivimäki
Antti
A
Burmeister
Florian
F
Naves de Brito
Arnaldo
A
Sorensen
Stacey L
SL
D004583:Electrons; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry; D013057:Spectrum Analysis; D013458:Sulfur Dioxide / Q000737:chemistry*
D013458:Sulfur Dioxide; D010126:Ozone; D010100:Oxygen