Novel feature of doubly bubble nuclei in 50 ≤ Z(N) ≤ 82 region along with magicity and weakly bound structure

In this work, we identify a unique and novel feature of central density depletion in both proton and neutron named as doubly bubble nuclei in [Formula: see text] region. The major role of 2d-3s single-particle (s.p.) states in the existence of halo and bubble nuclei is probed. The occupancy in s.p. state 3s[Formula: see text] leads to the extended neutron density distribution or halo while the unoccupancy results in the central density depletion. By employing the Relativistic Mean-Field (RMF) approach along with NL3* parameter, the separation energies, s.p. energies, pairing energies, proton and neutron density profiles along with deformations of even–even nuclei are investigated. Our results are concise with few other theories and available experimental data. Emergence on new shell closure and the magicity of conventional shell closures are explored systematically in this yet unknown region.

Multipole expansion of densities in the deformed relativistic Hartree–Bogoliubov theory in continuum

The deformed relativistic Hartree–Bogoliubov theory in continuum (DRHBc) has been proved as one of the best models to probe the exotic structures in deformed nuclei. In DRHBc, the potentials and densities are expressed in terms of the multipole expansion with Legendre polynomials, the dependence on which has only been touched for light nuclei so far. In this paper, taking a light nucleus [Formula: see text]Ne and a heavy nucleus [Formula: see text]U as examples, we investigated the dependence on the multipole expansion of the potentials and densities in DRHBc. It is shown that the total energy converges well with the expansion truncation both in the absence of and presence of the pairing correlation, either in the ground state or at a constrained quadrupole deformation. It is found that to reach the same accuracy of the total energy, even to the same relative accuracy by percent, a larger truncation is required by a heavy nucleus than a light one. The dependence of the total energy on the truncation increases with deformation. By decompositions of the neutron density distribution, it is shown that a higher-order component has a smaller contribution. With the increase of deformation, the high-order components get larger, while at the same deformation, the high-order components of a heavy nucleus play a more important role than that of a light one.

NEUTRON DENSITY DISTRIBUTIONS IN SPHERICALLY SYMMETRIC LEAD ISOTOPES

Based on a relativistic Thomas–Fermi model, it is shown that a two-parameter Fermi distribution can be used for describing the neutron density distribution in the 208 Pb nucleus.