Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 5: Posters Tuesday (Photoionisation, Multi Photon Processes)
A 5.6: Poster
Dienstag, 3. April 2001, 12:30–15:00, AT3
Spin polarisation in the resonant Auger decay of argon — •Burkhard Langer1, György Snell2,3, Sophie Canton2,3, and Nora Berrah2 — 1Max-Born-Institut, Berlin, Germany — 2Western Michigan University, Kalamazoo, MI, USA — 3Advanced Light Source, LBL, Berkeley, CA, USA
The dynamics of the photoionization and Auger decay processes can be fully described by the corresponding dipole and Coulomb transition matrix elements, respectively. A complete set of such matrix elements, amplitudes and phase shifts, enables the prediction of all parameters of the emission process, such as the angular distribution and spin polarisation of the electrons. In recent years, significant progress was achieved in the field of complete photoionization experiments. In contrast, only very few spin polarisation studies have been carried out for Auger decay processes [1]. Following the first measurements of the spin polarisation of resonant Auger electrons in Xe [1] we have measured the spin polarisation of resonant Auger electrons emitted from the decay of the Ar 2p−1→ 4s and 2p−1 → 3d excited states for the first time. We used monochromatized, circularly and linearly polarised light of 245 eV photon energy from the new elliptical polarization undulator (EPU) beamline at the Advanced Light Source (ALS) to carry out the experiment. Some of the Auger lines show a high degree of polarization, which will possibly enable the determination of Coulomb matrix elements.
[1] U. Hergenhahn, G. Snell, M. Drescher, B. Schmidtke, N. Müller, U. Heinzmann, M. Wiedenhöft, and U. Becker, Phys. Rev. Lett. 82, 5020 (1999).