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MO: Molekülphysik
MO 13: Photoionisation II (joint session A and MO)
MO 13.7: Talk
Friday, April 6, 2001, 17:15–17:30, H1012
Photo- and Auger-Electron Spectroscopy on Oriented CO and N2 — •Oliver Gessner, Jens Viefhaus, Rainer Hentges, Georg Prümper, and Uwe Becker — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin
The angular distributions of photo- und Auger-electrons emitted by CO-
and N2-molecules were measured in the molecular frame in the energy
region of the
1s inner shell excitation. The target molecules were not
statically
oriented before the photoionization took place, rather the molecular
orientation
was measured using a time- and position-resolved coincidence
technique [1]. This method enables us to measure photoelectron
angular distributions of oriented molecules and ion-emission angular
distributions for selected electron emission directions simultaneously.
By analysing both distributions we derived all matrix elements and
phase shifts describing the C1s inner shell photoionization of CO.
While direct photoionization has to be described by dipol matrix
elements, the effects of the resonant Auger-electron emission have to
be explained by Coulomb matrix elements. For the first time,
intramolecular
Auger-electron emission distributions following the
C1s-π∗
and N1s-π∗ excitation of free CO and N2,
respectively, are presented. They will be compared with theoretical
predictions and related measurements of non-resonant Auger processes.
[1] F. Heiser, O. Geßner, J. Viefhaus, K. Wieliczek, R. Hentges, and U. Becker, Phys. Rev. Lett. 79, 2435 (1997).
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