https://doi.org/10.1140/epja/i2004-10025-9
K-Mixing and fast decay of a seven-quasiparticle isomer in 179Ta
1
Nuclear Engineering Division, Argonne National Laboratory, IL 60439, Argonne, USA
2
Department of Nuclear Physics, R.S.Phys.S.E, Australian National University, ACT 0200, Canberra, Australia
3
Physics Division, Argonne National Laboratory, IL 60439, Argonne, USA
4
Department of Physics, The Faculties, Australian National University, ACT 0200, Canberra, Australia
5
Department of Physics, University of Massachusetts, MA 01854, Lowell, USA
* e-mail: kondev@anl.gov
A seven-quasiparticle isomer with and T
1/2 = 53 ( + 3
-7) ns has been identified in 179Ta. By comparing its excitation energy with results from multi-quasiparticle calculations that include the effects of blocking and residual nucleon-nucleon interactions, the isomer is assigned the
(5/2 + [402], 7/2 + [404],
(5/2-[512], 7/2-[514], 7/2-[503], 9/2 + [624]) configuration. The decay of this isomer is found to be unusually fast, a feature that is attributed to a mixing with a specific collective level. The interaction strength is found to be orders of magnitude lower than that observed between interacting collective levels.
© Società Italiana di Fisica and Springer-Verlag, 2004