The iron isotopic chain: A case study for neutron capture in the weak r-process region

Neutron capture rates is one of the worse quantitatively constrained of the quantities needed in order to understand isotopic abundances in the Universe. An accurate account involves a detailed knowledge of the reaction and structure aspects of the process, including the absorption of the neutron and the decay of the excited compound nucleus, emitting particles and electromagnetic radiation. Since experimental data on unstable isotopes is virtually nonexistent, the role of theory is particularly important, both for predicting neutron capture rates away from stability, and in designing indirect experimental measures. In addition, a unified theoretical description is very desirable in order to provide reliable estimates of the uncertainties involved in the theoretical predictions. We present here a systematic theoretical calculation of neutron capture rates along the iron isotopic chain. We will highlight the role of nuclear structure changes on the predicted rates as we move away from stability on the predicted cross sections, including the crossing of the N=28 neutron shell closure.