Nuclear Physics A 859 (2011) 172–184 www.elsevier.com/locate/nuclphysa The 76 Se Gamow–Teller strength distribution and its importance for stellar electron capture rates Q. Zhi a,b , K. Langanke a,c,d , G. Martínez-Pinedo a,∗ , F. Nowacki e,f , K. Sieja e,f a GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany b School of Physics and Electronic Science, Guizhou Normal University, Guiyang, PR China c Technische Universität Darmstadt, Germany d Frankfurt Institute for Advanced Studies, Frankfurt, Germany e Université de Strasbourg, IPHC, 23 rue du Loess 67037 Strasbourg, France f CNRS, UMR7178, 67037 Strasbourg, France Received 28 December 2010; received in revised form 31 March 2011; accepted 25 April 2011 Available online 3 May 2011 Abstract Recent theoretical studies predicted that, due to nuclear correlations across the N = 40 shell gap, elec- tron 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 con- firmed by the experimental determination of the single-particle occupation numbers in 76 Se and by the measurement of the 76 Se GT + strength distribution. In this manuscript we derive such occupation num- bers 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.  2011 Elsevier B.V. All rights reserved. Keywords: Beta decay; Electron capture; Core collapse supernova; Shell-model 1. Introduction Electron captures on nuclei play an essential role for the dynamics of the collapsing core in a supernova [1,2]. As during most of the collapse the pressure is dominated by the degenerate * Corresponding author. E-mail address: g.martinez@gsi.de (G. Martínez-Pinedo). 0375-9474/$ – see front matter  2011 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysa.2011.04.010