Hannover 2010 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 4: Photoionization I (exchanged with A1)
A 4.5: Vortrag
Montag, 8. März 2010, 17:45–18:00, F 303
Precise Determination of Valence Photoionisation Properties - From Precision Electron Spectroscopy to Molecular Two-Centre Interferences — •Markus Ilchen1, Markus Braune2, Sascha Deinert1, Leif Glaser1, Frank Scholz1, Peter Walter1, and Jens Viefhaus1 — 1Deutsches Elektronen Synchrotron, 22067 Hamburg — 2Fritz-Haber-Institut, 14195 Berlin
Angle resolved photoelectron spectroscopy was performed with an online analysis tool which has been set up for determining several beamline parameters of the P04 beamline at PETRA III, DESY. The device is capable of giving users an online feedback of e.g. the degree of polarization within seconds without affecting the beam. Building a precise database of anisotropy parameters β for many gases in a wide energy range is the basis for this task. An intrinsic benefit of this method is that actual literature is evaluated and complex phenomena can be analysed in detail. Highly precise angle resolving measurements for the valence photoionization of N2 and O2 are presented in a low energy range from 19 - 50 eV in comparison to other authors [1,2]. Concerning the data calibration, modified data for the β-literature of Neon [3] is presented. In a collaboration with the Fritz-Haber-Institut, additional measurements of N2 and O2 in a wider energy range show Cohen-Fano oscillations due to interference of two-centre electron emission [4].
[1] S.H. Southworth et al, Phys. Rev. A 33 (1986) 1020.
[2] I. Iga et al, J. Phys. B 22 (1989) 2991.
[3] F. Wuilleumier and M.O. Krause, JESRP 15 (1976) 15.
[4] H.D. Cohen and U. Fano, Phys. Rev. 150 (1966) 30.