One-particle properties of deformed N≈28 odd-N nuclei with weakly bound or resonant neutrons

Possible deformation of odd-N nuclei with N≈28 toward the neutron drip line is investigated using the Nilsson diagram based on deformed Woods-Saxon potentials. Both weakly-bound and resonant one-particle levels are properly obtained by directly solving the Schrödinger equation in mesh of space coordinate with the correct boundary condition. If we use the same diffuseness of the potential as that of β-stable nuclei, the energy difference between the neutron 2p_3/2 and 1f_7/2 levels becomes very small or the N=28 energy gap almost disappears, as the binding energies of those levels approach zero. This suggests that the ground states of those neutron drip line nuclei are likely to be deformed. In particular, the spin-parity and the magnetic moment of the ground state of odd-N nuclei, ₁₆⁴³S₂₇ and ₁₆⁴⁵S₂₉, are examined. Moreover, it is suggested that in ₁₂³⁹Mg₂₇ lying outside the drip line the lowest resonant state may have 5/2^-, if the N=28 energy gap almost vanishes.