Coupling highly excited nuclei to the atomic shell in dense astrophysical plasmas

Abstract

In dense astrophysical plasmas, neutron capture populates highly excited nuclear states close to the neutron threshold. The impact of additional low-energy nuclear excitations via coupling to the atomic shell on the ability of the so-formed compound nucleus to retain the captured neutron is investigated. We focus on the mechanism of nuclear excitation by electron capture in plasmas characterized by electron fluxes typical for the slow neutron capture process of stellar nucleosynthesis. The small effect of this further excitation on the neutron capture and gamma decay sequence relevant for nucleosynthesis is quantified and compared to the corresponding effect of an additional low-energy photoexcitation step.

11 pages, 10 figures; v2 minor modifications to match the published version, results unchanged

References in corpus (6)

• Measurement of the ${\beta }^{+}$ and orbital electron-capture decay rates in fully-ionized, hydrogen-like, and helium-like ${}^{140}$Pr ions
• Isomer triggering via nuclear excitation by electron capture
• Theory of nuclear excitation by electron capture for heavy ions
• Nuclear excitation by electron capture followed by fast x-ray emission
• Modification of nuclear transitions in stellar plasma by electronic processes: K-isomers in 176Lu and 180Ta under s-process conditions
• Nuclear Level Densities in the Constant-Spacing Model