Two-quasiparticle structures and isomers in {sup 168}Er, {sup 170}Er, and {sup 172}Er.

Journal Article · Sat May 01 04:00:00 EDT 2010 · Phys. Rev. C

DOI:https://doi.org/10.1103/PhysRevC.81.054313· OSTI ID:982680

Dracoulis, G D; Lane, G J; Kondev, F G; Watanabe, H; Seweryniak, D; Zhu, S; Carpenter, M P; Chiara, C J; Janssens, R V. F.; Lauritsen, T; Lister, C J; McCutchan, E A; Stefanescu, I; RIKEN,

The stable and neutron-rich isotopes 168Er, 170Er, and 172Er have been studied with Gammasphere using inelastic excitation with energetic 136Xe beams. The previously assigned structures based on the proposed K?=4- isomeric intrinsic states in both 168Er and 170Er have been re-evaluated and an equivalent band identified in 172Er. In 170Er, the identification of a K?=6- band with transitions close in energy to those of the 4- band leads to a modified interpretation, since the overlap would have compromised previous analyses. The gK-gR values for the 4- bands deduced from the in-band ?-ray intensities for the sequence of isotopes suggest a predominantly two-neutron configuration in 168Er, an equally mixed two-neutron, two-proton configuration in 170Er, and a two-proton configuration in 172Er. A comprehensive decay scheme for the previously proposed 6+ isomer in 172Er has also been established, as well as band structures built on this isomer that closely resemble the 6+ and 7- two-neutron structures known in the isotone 174Yb. The implied K hindrances are discussed. The main decay path of the 6+ isomer occurs through the newly identified 4- isomer. The measured lifetimes of the 4- and 6+ isomers in 172Er are 57(3) and 822(90) ns, respectively. Multiquasiparticle calculations support the suggested configuration changes across the isotopic chain.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; Australian Research Council Discovery Program
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 982680
• Report Number(s): ANL/PHY/JA-66447
• Journal Information: Phys. Rev. C, Journal Name: Phys. Rev. C Journal Issue: May 2010 Vol. 81; ISSN 0556-2813
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BEAMS
CONFIGURATION
DECAY
ENERGY
EXCITATION
ISOMERS
ISOTONIC NUCLEI
ISOTOPES
NEUTRON-RICH ISOTOPES
SUPPORTS
WELLS