Isomer spectroscopy in 133Ba and high-spin structure of 134Ba
Abstract
The transitional nuclei 134Ba and 133Ba are investigated after multinucleon transfer employing the high-resolution Advanced GAmma Tracking Array coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and after fusion-evaporation reaction at the FN tandem accelerator of the University of Cologne, Germany. The Jπ=19 /2+ state at 1942 keV in 133Ba is identified as an isomer with a half-life of 66.6 (20 )ns corresponding to a B (E 1 ) value of 7.7 (4 ) ×10-6e2fm2 for the Jπ=19 /2+ to Jπ=19 /2- transition. The level scheme of 134Ba above the Jπ=10+ isomer is extended to approximately 6 MeV. A pronounced backbending is observed at ℏ ω =0.38 MeV along the positive-parity yrast band. The results are compared to the high-spin systematics of the Z =56 isotopes. Large-scale shell-model calculations employing the GCN50:82, SN100PN, SNV, PQM130, Realistic SM, and EPQQM interactions reproduce the experimental findings and elucidate the structure of the high-spin states. The shell-model calculations employing the GCN50:82 and PQM130 interactions reproduce alignment properties and provide detailed insight into the microscopic origin of this phenomenon in transitional 134Ba.
- Publication:
-
Physical Review C
- Pub Date:
- August 2019
- DOI:
- 10.1103/PhysRevC.100.024323
- Bibcode:
- 2019PhRvC.100b4323K