The {sigma}* absorption peak at the oxygen 1{ital s} edge of O{sub 2}: Exchange splitting, ultrafast dissociation, and atomiclike Auger spectra
- Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- Theoretical Chemistry Section, Code 6179, Naval Research Laboratory, Washington, D.C. 20375 (United States)
The x-ray absorption spectrum of solid O{sub 2} at the O 1{ital s} absorption edge is analyzed, using its polarization dependence and the Auger de-excitation spectra. Rydberg states are quenched in the solid, and the exchange splitting of the 1{ital s} ionization threshold (1.1 eV) can be observed. Below the ionization threshold, core electrons can be excited into unoccupied antibonding {pi}* and {sigma}* orbitals. We conclude from the relative intensities and from the polarization dependence, that the exchange splitting of the {sigma}* final state is small ({lt}1 eV). This is confirmed by LDA calculations of core-excited states. The calculated {sigma}* potential surfaces are repulsive, which explains the large width of this absorption peak. Because of ultrafast dissociation ({similar_to}5 fs), core hole decay is likely to occur at large interatomic distances. Auger spectra at the {sigma}* absorption of O{sub 2} do indeed show peaks that would be expected for free core-excited oxygen atoms.
- Research Organization:
- Brookhaven National Laboratory
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 143285
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 6 Vol. 100; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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