Studies of Deformed Halo Structures of 39Na and 42Mg

Abstract

Background: The recent experimental discovery of drip-line nucleus ³⁹Na has attracted great interest in theoretical studies of exotic nuclear structures in this mass region. Methods: We solve the Skyrme–Hartree–Fock–Bogoliubov (Skyrme-HFB) equation within deformed coordinate-spaces. The present approach is suitable for descriptions of weakly bound deformed nuclei with continuum effects and deformed halo structures. Results: The systematical two-neutron separation energies are obtained with the SkM${}_{\mathrm{ext}1}^{*}$ and UNEDF0${}_{\mathrm{ext}1}$ forces for Na and Mg isotopes close to the neutron drip line. The density distributions show that ${}^{39}$Na and ${}^{42}$Mg have deformed halo structures. Furthermore, there are significant influences of various pairing interactions on halo shapes at large distances. Conclusions: Both ${}^{39}$Na and ${}^{42}$Mg are very weakly bound with well prolate deformed cores. However, their surface halo structures are dependent on the choices of pairing interactions. The volume-type pairing interaction tends to predict a prolate deformed halo, while the halo deformations at large distances are reduced by adopting the surface pairing. We demonstrate that ${}^{39}$Na and ${}^{42}$Mg are promising candidates for two-neutron deformed halo nuclei.