Peninsula of neutron stability of nuclei in the neighborhood of neutron magic number N = 126

Abstract

The properties of the ground state of even-even nuclei with extreme neutron excess that are remote from the known neutron drip line (NDL) are calculated. The calculations are based on the Hartree-Fock method with Skyrme forces SkM*, SkI2, Sly4, Ska) with allowance for axial deformation and the BCS pairing approximation. It is shown that the isotone chain at the neutron number N = 126 beyond the NDL forms a peninsula of nuclei that are stable with respect to the emission of one neutron (PNS). The neutron and proton density distributions of the PNS nuclei have spherical symmetry. A mechanism for restoring the stability of nuclei beyond the NDL is discussed. The obtained results are compared with those from Hartree-Fock-Bogoliubov calculations for long isotope chains of Zr and Pd up to the NDL.

Investigation of the properties of nuclei with extreme neutron excess in the vicinity of neutron magic numbers

“…We obtained similar diagrams with other parameterizations of the Skyrme forces as well [12][13][14][15]. The grey region in the NZ diagram shows the atomic nuclei known from experiments.…”

“…In our DHF calculations, such pairing was considered only in the space of bound sin gle particle states due to the difficulties [29] that arise in solving HF equations with methods in which the HF wave function is expanded in a series in the wave functions of an axially deformed harmonic oscillator. Despite this simplification in our consideration of pairing, our results [12][13][14][15] were in very good agree ment up to the NDL with calculations by the HFB method [2,3]. The HFB calculations in [2,3], in which the continuum was considered, are usually regarded as the standard in the literature.…”

“…Later [10][11][12][13][14][15], we showed that beyond the NDL there could be PSes for nuclei with extremely large neutron excess in the vicinity of the magic and new magic numbers N = 32, 58, 82, 126, 184, and 258. It was shown that the positions of those PSes in (N, Z) space did not depend on our choice of Skyrme forces (Ska [16], SkM* [17], Sly4 [18], SkI2 [19], SkP [20]), while the length of the PSes was sensitive to the choice of the forces.…”

“…RESULTS AND DISCUSSION Figure 1 shows an NZ diagram of atomic nuclei that presents DHF calculations [12][13][14][15] with SkM* parameterization of the Skyrme forces. We obtained similar diagrams with other parameterizations of the Skyrme forces as well [12][13][14][15].…”

“…magic numbers for which nucleon stability is seen to increase [12][13][14][15]33]. The solid line connecting the black squares is the 1n NDL obtained from HFB cal culations [2,3] with SkM* forces.…”