Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 6: Spectroscopy
A 6.6: Vortrag
Dienstag, 3. April 2001, 17:00–17:15, H1028
Coherence transfer in the Auger cascades of resonantly excited noble gases — •S. Fritzsche1, N. M. Kabachnik2, H. Chiba3, T. Hayaishi4, M. Hoshino5, M. Kitajima5, M. Okamoto5, Y. Shimizu3, H. Tanaka5, and K. Ueda3 — 1Universität Kassel, D–34132 Kassel, Germany. — 2Universität Bielefeld, D–33615 Bielefeld, Germany. — 3Tohoku University, Sendai 980–8577, Japan. — 4University of Tsukuba, Tsukuba 305–8577, Japan. — 5Sophia University, Tokyo 102–8554, Japan.
Angle–resolved Auger electron spectroscopy provides a unique tool for studying the excitation and decay mechanisms in atomic many–particle systems. With improved synchrotron light sources and electron spectrometers, nowadays experiments yield a spectral resolution much higher than the natural widths of individual lines. These experiments may therefore help understand the alignment transfer and angular correlations among subsequently emitted electrons in Auger cascades. In this contribution, we report about a detailed theoretical and experimental study of the transitions following the 2p → 4s and 3d → 5p photo–excited states in argon [1] and krypton, respectively. These states mainly decay in a two–step process via the ns−1np−1(n+1)l′ and ns−2(n+1)l′ levels (n = 3,4) to the double ionized np 4 states, a process which leads to the coherent excitation of nearly degenerated intermediate levels. To understand the alignment transfer through the cascade and the angular correlation between the emitted electrons, a series of multiconfiguration calculations have been carried out. These investigations show the strong influence of correlation effects on the description of angle–dependent properties. Even for quite large wave function expansions, the theoretical anisotropy and angular correlation parameters disagree with experiment for some of the transitions.
[1] K. Ueda, Y. Shimizu, H. Chiba, M. Kitajima, H. Tanaka, S. Fritzsche and N. M. Kabachnik, J. Phys. B34 (2001) 107.