Eur. Phys. J. A (2005) 25: 357-362
https://doi.org/10.1140/epjad/i2005-06-025-1

ENAM 2004

Shell structure from ¹⁰⁰Sn to ⁷⁸Ni: Implications for nuclear astrophysics

¹ GSI, Planckstr. 1, D-64291, Darmstadt, Germany
² University of Sofia, Sofia, Bulgaria
³ Katholieke Universiteit Leuven, Leuven, Belgium
⁴ RRC “Kurchatov Institute”, RU-123481, Moscow, Russia
⁵ Yale University, New Haven, CT, USA
⁶ IReS, Strasbourg, Cedex 2, France
⁷ ORNL, Oak Ridge, TN, USA
⁸ IEP Warsaw University, Warsaw, Poland

^* e-mail: h.grawe@gsi.de

Received: 11 November 2004
Accepted: 18 February 2005
Published online: 25 April 2005

Abstract

The single-particle structure and shell gap of ¹⁰⁰Sn is inferred from prompt in-beam and delayed γ-ray spectroscopy of seniority and spin-gap isomers. Recent results in ^{94, 95}Ag and ⁹⁸Cd stress the importance of large-scale shell model calculations employing realistic interactions for the isomerism, np-nh excitations and E2 polarisation of the ¹⁰⁰Sn core. The strong monopole interaction of the Δl = 0 spin-flip partners πg _9/2- νg _7/2 in N = 51 isotones below ¹⁰⁰Sn is echoed in the Δl = 1 πf _5/2- νg _9/2 pair of nucleons, which is decisive for the persistence of the N = 50 shell gap in ⁷⁸Ni. This is corroborated by recent experimental data on ^{70, 76}Ni, ⁷⁸Zn. The importance of monopole driven shell evolution for the appearance of new shell closures in neutron-rich nuclei and implications for r-process abundances near the N = 82 shell is discussed.