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

Journal Article · Sat May 15 04:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.81.054313· OSTI ID:21389021

Dracoulis, G D; Lane, G J ^[1]; Kondev, F G; Chiara, C J ^[2]; Watanabe, H ^[3]; Seweryniak, D; Zhu, S; Carpenter, M P; Janssens, R V. F.; Lauritsen, T; Lister, C J; McCutchan, E A ^[4]; Stefanescu, I ^[4]

---

1. Department of Nuclear Physics, R.S.P.E, Australian National University, Canberra ACT 0200 (Australia)
2. Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
3. RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
4. Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

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

• OSTI ID: 21389021
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 5 Vol. 81; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYONS
BEAMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COMPUTERIZED SIMULATION
CONFIGURATION
DAYS LIVING RADIOISOTOPES
DECAY
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY-LEVEL TRANSITIONS
ERBIUM 168
ERBIUM 170
ERBIUM 172
ERBIUM ISOTOPES
EVEN-EVEN NUCLEI
EXCITATION
FERMIONS
GAMMA RADIATION
HADRONS
INELASTIC SCATTERING
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOMERS
ISOTOPES
LIFETIME
NEUTRON-RICH ISOTOPES
NEUTRONS
NUCLEAR DECAY
NUCLEI
NUCLEONS
PROTONS
RADIATIONS
RADIOISOTOPES
RARE EARTH NUCLEI
SCATTERING
SIMULATION
STABLE ISOTOPES
XENON 136
XENON ISOTOPES
YTTERBIUM 174
YTTERBIUM ISOTOPES