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. The free energy surfaces as well as the bulk properties including deformations, pairing gaps, excitation energy, and specific heat for the global minimum are studied. 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. The transition temperatures are roughly proportional to the corresponding deformations at the ground states.

19 pages, 11 figures

References in corpus (7)

• Relativistic Continuum Hartree Bogoliubov Theory for Ground State Properties of Exotic Nuclei
• New parametrization for the nuclear covariant energy density functional with point-coupling interaction
• Shell Structure and $\rho$-Tensor Correlations in Density-Dependent Relativistic Hartree-Fock theory
• Octupole deformation properties of the Barcelona-Catania-Paris energy density functionals
• Compilation of Giant Electric Dipole Resonances Built on Excited States
• Effect of temperature on the effective mass and the neutron skin of nuclei
• Octupole deformation for Ba isotopes in a reflection-asymmetric relativistic mean-field approach

Cited by in corpus (9)

• Microscopic core-quasiparticle coupling model for spectroscopy of odd-mass nuclei with octupole correlations
• Continuum Skyrme-Hartree-Fock-Bogoliubov theory with Green's function method for odd-$A$ nuclei
• Searching for single-particle resonances with the Green's function method
• Finite-temperature electron-capture rates for neutron-rich nuclei around N=50 and effects on core-collapse supernovae simulations
• Microscopic model for the collective enhancement of nuclear level densities
• Study of single-particle resonant states with Green's function method
• Clustering in nuclei at finite temperature
• Thermodynamics of pairing transition for Odd-A nuclei
• Microscopic quasifission dynamics of the ${}^{54}\text{Cr}+{}^{243}\text{Am}$ reaction