A systematic study of neutron magic nuclei withN= 8, 20, 28, 50, 82 and 126 in the relativistic mean-field theory

We perform a systematic study of all the traditional neutron magic nuclei with N = 8, 20, 28, 50, 82 and 126, from the neutron drip line to the proton drip line. We adopt the deformed relativistic mean-field theory as our framework and treat pairing correlations by a simple BCS method with a zero-range δ-force. Remarkable agreement with the available experimental data is obtained for the binding energies, the two- and one-proton separation energies, and the nuclear charge radii. The calculated nuclear deformations are compared with the available experimental data and the predictions of the FRDM mass formula and the HFBCS-1 mass formula. We discuss, in particular, the appearance of sub-shell magic nuclei by observing irregular behaviour in the two- and one-proton separation energies.