The role of seniority-zero states in nuclear level densities

Research output: Contribution to journalArticle


At low excitation energies seniority-zero states dominate the level density of K = 0 bands in deformed even even nuclei, while they play no role at higher excitation energies. We describe the level densities in a Fermi-gas model as well as in a combinatorial level-density model and compare to detailed experimental data for some rare-earth nuclei. An explanation is provided for recent observations of an odd even staggering in the spin-distribution function as an effect of r-symmetry of wave functions for deformed nuclei. The structure of 0(+) states in deformed nuclei is discussed in the model and compared to data, stressing the role of the seniority quantum number. The Fermi-gas model is utilized to obtain an overview of the odd even staggering phenomenon in other mass regions. Odd even staggering in spherical nuclei, appearing in open-shell nuclei, is briefly discussed as caused by fermion exchange symmetry. (C) 2015 Elsevier B.V. All rights reserved.


External organisations
  • Niels Bohr Institute
  • Los Alamos National Laboratory
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Subatomic Physics


  • Level-density, Seniority-zero states, Spin-distribution, 0(+)-states
Original languageEnglish
Pages (from-to)97-120
JournalNuclear Physics, Section A
Publication statusPublished - 2015
Publication categoryResearch

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Mathematical Physics (Faculty of Technology) (011040002)