Title: Shape transition with temperature of the pear-shaped nuclei in covariant density functional theory

Abstract

The shape evolutions of the pear-shaped nuclei $$^{224}$$Ra and even-even $$^{144-154}$$Ba with temperature are investigated by the finite-temperature relativistic mean field theory with the treatment of pairing correlations by the BCS approach. We study the free energy surfaces as well as the bulk properties including deformations, pairing gaps, excitation energy, and specific heat for the global minimum. For $$^{224}$$Ra, three discontinuities found in the specific heat curve indicate the pairing transition at temperature 0.4 MeV, and two shape transitions at temperatures 0.9 and 1.0 MeV, namely one from quadrupole-octupole deformed to quadrupole deformed, and the other from quadrupole deformed to spherical. Furthermore, the gaps at $N$=136 and $Z$=88 are responsible for stabilizing the octupole-deformed global minimum at low temperatures. Similar pairing transition at $$T\sim$$0.5 MeV and shape transitions at $T$=0.5-2.2 MeV are found for even-even $$^{144-154}$$Ba. Finally, the transition temperatures are roughly proportional to the corresponding deformations at the ground states.

Authors:

Zhang, Wei ^[1]; Niu, Yi-Fei ^[2]

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+ Show Author Affiliations

1. Zhengzhou Univ. (China). Henan Key Lab. of Ion-beam Bioengineering; Chinese Academy of Sciences (CAS), Xi'an (China). Key Lab. of Precision Navigation and Technology; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry
2. Horia Hulubei National Inst. for Physics and Nuclear Engineering, Bucharest-Magurele (Romania). Extreme Light Infrastructure-Nuclear Physics (ELI-NP)

Publication Date:

2017-11-10

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Natural Science Foundation of China (NNSFC)

Contributing Org.:

.

OSTI Identifier:

1408225

Alternate Identifier(s):

OSTI ID: 1408264

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review C

Additional Journal Information:

Journal Volume: 96; Journal Issue: 5; Journal ID: ISSN 2469-9985

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

73 NUCLEAR PHYSICS AND RADIATION PHYSICS; covariant density functional; finite temperature; shape transition