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A: Atomphysik

A 10: Posters Wednesday (Cooling and Trapping, Electron Scattering and Recombination)

A 10.13: Poster

Mittwoch, 4. April 2001, 12:30–15:00, AT3

Measurement of Spin-Asymmetries in Elastic Electron - Cs Scattering at Intermediate Energies. — •Nataša Pavlovic, Bernhard Roth, and Günter Baum — Fakultät Physik, Universität Bielefeld

The determination of spin-polarization effects in electron scattering from Cs atoms has provided a challenge, experimentally as well as theoretically, for many years. We have used crossed electron and atomic beams, both spin-polarized, to measure the angular dependences of the spin-asymmetries A₁, A₂, and A_nn at selected energies in the range from 4 to 25 eV. The asymmetries can be related to electron exchange processes (A_nn), to relativistic/spin-orbit effects (A₂), or to an interference of these two mechanisms (A₁). We will present our results for these asymmetries as well as our results for the relative differential cross section. A comparison can be made in this theoretically difficult intermediate energy regime with recent calculations, which use either the relativistic R matrix method [1], or the convergent close-coupling method [2]. Before, we had reported on theoretical and experimental benchmark data at low-energy (3 eV) [3].

[1] K. Bartschat, private communication (2000).

[2] I. Bray, private communication (2000).

[3] G. Baum et al., Phys. Rev. Lett. 82, 1128 (1999)