Hannover 2013 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 41: Poster: Electron scattering and recombination

A 41.1: Poster

Donnerstag, 21. März 2013, 16:00–18:30, Empore Lichthof

Coupling Nuclei to the Atomic Shells in Stellar Environments — •Stephan Helmrich1,2 and Adriana Pálffy11Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg — 2Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg

The role of processes coupling nuclear transitions to the atomic shells has been investigated in dense stellar plasma conditions. In particular addressed was the process of nuclear excitation by electron capture (NEEC) [1], in which the recombination of a free electron into a highly charged ion leads to the simultaneous excitation of the nucleus. In the context of isomer depletion, the role of NEEC in populating low-lying nuclear excited states under dense stellar plasma conditions has been previously investigated [2].

Here we study a different scenario, in which NEEC occurs not from the nuclear ground state but instead from highly excited states close to the neutron threshold. Such states are reached in dense astrophysical plasmas via neutron capture. The impact of such additional nuclear excitations on the neutron capture and gamma decay sequence which is relevant for s-process nucleosynthesis is investigated. Our results show that for electron fluxes typical for the s-process, NEEC does not influence the nucleosynthesis sequence. Higher plasma temperatures as typical for r-process nucleosynthesis also do not favor the coupling to the atomic shells, but rather processes like photoabsorption.

[1] A. Pálffy, W. Scheid and Z. Harman, Phys. Rev. A 73, 012715 (2006)

[2] G. Gosselin, P. Morel and P. Mohr, Phys. Rev. C 81, 055808 (2010)

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