Odd-even differences in the stability “peninsula” in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>106</mml:mn><mml:mo>≤</mml:mo><mml:mi>Z</mml:mi><mml:mo>≤</mml:mo><mml:mn>112</mml:mn></mml:mrow></mml:math> region with the deformed relativistic Hartree-Bogoliubov theory in continuum

Abstract

The predictive power of the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) with density functional PC-PK1 is demonstrated for superheavy region ($101\ensuremath{\leqslant}Z\ensuremath{\leqslant}120$) by comparing with available experimental and evaluated data from AME2020. The DRHBc theory predicts 93 bound nuclei beyond the drip line $N=258$ in the region of $106\ensuremath{\leqslant}Z\ensuremath{\leqslant}112$, which form a stability peninsula. The odd-even differences between $\mathrm{odd}\text{\ensuremath{-}}N$ and even-$N$ nuclei are remarkable in the peninsula; the one-neutron separation energy of an $\mathrm{odd}\text{\ensuremath{-}}N$ nucleus is smaller than those of its neighboring even-$N$ nuclei due to the blocking effect, and as a result the number of bound $\mathrm{odd}\text{\ensuremath{-}}N$ nuclei is less than that of bound even-$N$ nuclei. The deformation effect is indispensable for the re-entrant stability beyond the drip line by significantly affecting the structure of single-particle levels around the Fermi energy. The interplay between deformation and pairing influences the location of the first bound $\mathrm{odd}\text{\ensuremath{-}}N$ nucleus in the peninsula. By examining the deformation effect at different orders, it is found that quadrupole deformation ${\ensuremath{\beta}}_{2}$ contributes predominantly to the appearance of stability peninsula, and the effects of higher-order deformations ${\ensuremath{\beta}}_{4}$ and ${\ensuremath{\beta}}_{6}$ are non-negligible.

Topics & Concepts