Isotopic shift in magic nuclei within relativistic mean-field formalism

Abstract

The ground-state properties such as binding energy, root-mean-square radius, pairing energy, nucleons density distribution, symmetry energy, and single-particle energies are calculated for the isotopic chain of Ca, Sn, Pb, and Z = 120 nuclei. The recently developed G3 and IOPB-I forces along with the DD-ME1 and DD-ME2 sets are used in the analysis employing the relativistic mean-field approximation. To locate the magic numbers in the superheavy region and to explain the observed kink at neutron number N = 82 for Sn isotopes, a three-point formula is used to see the shift of the observable and other nuclear properties in the isotopic chain. Unlike the electronic configuration, due to strong spin-orbit interaction, the higher spin orbitals are occupied earlier than the lower spin, causing the possible kink at the neutron magic numbers. We find peaks at the known neutron magic number with the confirmation of sub-shell, shell closure respectively at N = 40, 184 for Ca and 304120.

Appearance of peak in symmetry energy at N = 126 for Pb isotopic chain within relativistic energy density functional

“…2. Furthermore, from Brückner's prescription, no significant peak is found at N = 126 shell closure, corresponding to 208 Pb as also reported in earlier studies [8,11,12,36,37] and the references therein. This peak shifted to N=120 which is not a close shell for Pb nucleus.…”

“…This is one of the most essential characteristics of nuclei that lies far from the stability line. Several recent studies have unequivocally demonstrated that the presence of kinks in symmetry energy of finite nuclei over the isotopic chain points to the existence of magic numbers [7][8][9][10][11][12]. The advancement in the sophisticated experimental radioactive ion beam facilities using the projectile-fragmentation reaction method with fast ion-beams at FRIB (USA) [13], RIKEN (Japan) [14], GSI (Germany) [15], FLNR (Russia) [16], CSR (China) [17] and SPIRAL2/GANIL (France) [18] have led to the renaissance of investigating the behaviour of symmetry energy at and above the saturation density [19].…”

“…Recently, the surface properties of nuclei can be estimated by using the non-relativistic and relativistic inputs within the coherent density fluctuation model (CDFM) [8,11,12,36,37]. From these analysis, one can find the notable peaks/kinks that have been observed for traditional magic neutron and/or proton.…”

“…The peak in the surface properties such as nuclear symmetry energy and its component are used as indicators of shell/sub-shell closure [8,11,12,36,37]. The possible reasons for the disappearance of the peak at neutron number N=126 for Pb nuclei have been discussed.…”

Theoretical Investigation of α-decay Chains of Fm-isotopes

“…However, the decay channels 231 Pu+ 4 He and 233 Pu+ 4 He displays a departure from the norm (highlighted in the footnote a), signifying the presence of a shell/sub-shell closure at N=139, 141 and Z=94 which corresponds to 231 Pu and 233 Pu, respectively. This is somewhat reminiscent of the appearance of peaks/kinks in symmetry energy of finite nuclei across the isotopic chain as indicators of shell/sub-shell closures [38][39][40].…”