Hannover 2010 – scientific programme
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A: Fachverband Atomphysik
A 4: Photoionization I (exchanged with A1)
A 4.6: Invited Talk
Monday, March 8, 2010, 18:00–18:30, F 303
Two-Center Interference in Valence Photoionization of N2 and O2 — •Markus Braune1, Markus Ilchen2, Sanja Korica1, Andre Meißner1, Lokesh Tribedi1, Sascha Deinert2, Leif Glaser2, Frank Scholz2, Peter Walter2, Jens Viefhaus2, and Uwe Becker1 — 1Fritz-Haber-Institut, 14195 Berlin — 2DESY, 22607 Hamburg
Cohen and Fano derived their famous formula for the oscillation of the partial cross sections of homonuclear diatomic molecules in 1966 [1]. The oscillatory behavior in the valence photoionization of N2 and O2 which they presented as experimental evidence turned out to be basically an intensity variation due to a shape resonance rather than a signature of coherent emission from two emitter sites. The oscillation period of a real Cohen-Fano type oscillation depends on the internuclear distance and extends over a broad energy range as has been proven many years later for the 1s core photoionization of H2 [2] and N2 [3]. Most recently, we analyzed the valence photoionization of N2 and O2 used as an example by Cohen and Fano by means of angular resolved photoelectron spectroscopy in a collaboration with DESY. We present first data of Cohen-Fano oscillations concerning outer valence partial cross sections and angular distribution asymmetry parameters. The results are compared with recent theoretical calculations [4].
[1] Cohen H D and Fano U, Phys. Rev. 150, 30 (1966)
[2] N. Stolterfoht et al., Phys. Rev. Lett. 87, 23201 (2001).
[3] B. Zimmermann et al., NPhys. 4, 649 (2008)
[4] D. Toffoli, P. Decleva, J. Phys. B 39, 2681 (2006)