The 76Se Gamow-Teller strength distribution and its importance for stellar electron capture rates

Recent theoretical studies predicted that, due to nuclear correlations across the N = 40 shell gap, electron captures on nuclei with proton numbers Z <40 and neutron numbers N > 40 would not be strongly suppressed due to Pauli blocking of Gamow-Teller (GT) transitions. This prediction has recently been confirmed by the experimental determination of the single-particle occupation numbers in Se-76 and by the measurement of the Se-76 GT(+) strength distribution. In this manuscript we derive such occupation numbers and GT(+) distributions within large-scale shell model studies. Based on the same models, we calculate stellar electron capture rates and compare them to those obtained from the experimental GT(+) data. (C) 2011 Elsevier B.V. All rights reserved.