Relativistic self-consistent mean-field description of Sm isotopes

Abstract

The evolution of the shape from the spherical to the axially deformed shapes of the neutron-rich, even-even $^{144\text{--}164}\mathrm{Sm}$ transitional nuclei is investigated. The investigations are performed with explicit density-dependent meson-nucleon and point-coupling models within the framework of the covariant density functional theory. A nonlinear meson-nucleon coupling model represented by the NL3* parametrization of the relativistic mean-field Lagrangian has also been used. The bulk and the microscopic properties of these nuclei have been investigated to analyze the phase-transition region and the critical-point behavior. The microscopic and self-consistent quadrupole deformation-constrained calculations show a clear shape change for even-even Sm isotopes with $N=82\ensuremath{-}102$. The potential energy surfaces for $^{148}\mathrm{Sm},^{150}\mathrm{Sm}$, and $^{152}\mathrm{Sm}$ obtained using different interactions are found to be relatively flat, which may be the possible critical-point nuclei. By examining the single-particle spectra, it is found that these nuclei distribute more uniformly as compared to other isotopes. Investigations also support the proposed shell-closure properties of $^{162}\mathrm{Sm}$. Overall good agreement is found within the different models used and between the calculated and experimental results wherever available.