I {approximately} 60 {dirac_h} in {sup 156}Dy : competition between collective and terminating structures at very high-spin.
The highest-spin discrete states (I {approx} 60 {Dirac_h}and E{sub x}{approx}30 MeV) in normal deformed nuclei have been observed in the rare-earth isotope {sup 156}Dy using the {sup 124}Sn({sup 36}S,4n) reaction in conjunction with the GAMMASPHERE spectrometer. The positive parity yrast sequence appears to evolve smoothly from a prolate (collective) towards an oblate (non-collective) shape, in contrast to the sudden shape change observed in the isotone {sup 158}Er. Terminating states are identified in the negative parity sequences at I{sup {pi}}=52{sup -} and 53{sup -} and specific multi-particle-hole configurations are assigned by comparison with cranked Nilsson-Strutinsky calculations. An order of magnitude increase in the interaction strength between close lying high-spin weakly collective structures is determined compared with that found in the lower-spin strongly collective domain. These results give valuable insight into the interplay between collective and terminating structures, and their competition for yrast status in the 40 {approx} 60 {Dirac_h}spin range.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- ER
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 938363
- Report Number(s):
- ANL/PHY/JA-29753; PYLBAJ; TRN: US200908%%306
- Journal Information:
- Phys. Lett. B, Vol. 437, Issue 1998; ISSN 0370-2693
- Country of Publication:
- United States
- Language:
- ENGLISH
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