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A: Fachverband Atomphysik
A 14: Posters: Interaction of matter with ions
A 14.16: Poster
Dienstag, 11. März 2008, 16:30–18:30, Poster C3
Theoretical analysis of cascading effects on the nonstatistical enhancement of the 1s2s2p 4P state in electron transfer in C4+-He collisions — •Dennis Röhrbein1, Tom Kirchner1, Stephan Fritzsche2,3, Diane Strohschein4, Jamie Baran4, and John Tanis4 — 1Institut für Theoretische Physik, TU Clausthal, D-38678 Clausthal-Zellerfeld — 2GSI, D-64291 Darmstadt — 3Max-Planck-Institut für Kernphysik, D-69029 Heidelberg — 4Department of Physics, Western Michigan University, Kalamazoo MI 49008, USA
In several experiments nonstatistical enhancements for formation of the metastable 1s2s2p 4P state compared to the similarly configured 1s2s2p 2P− and 1s2s2p 2P+ states following single electron transfer to a 1s2s 3S state have been observed. The enhancements were attributed to a dynamical Pauli exchange mechanism involving projectile and target electrons having the same spin alignment. Recently, it was suggested that the enhancements might be due to cascading effects following electron transfer to levels with n≥ 3.
To test the latter interpretation we have combined dynamical capture calculations on the single-particle level with structure calculations for the relevant excited three-particle states. The E1 transition rates have been calculated for all these states up to n=5, and the dynamical rate equations solved to obtain total cross sections for the final 4P and 2P states under consideration. These results are compared with new measurements for 500-1000 keV/amu C4+-He collisions. It is found that cascade feeding due to capture into n≥ 3 levels does indeed play a role, but explains only about half of the observed enhancement.