Relativistic Mean-Field Theory and the Structural Properties of Ne, Mg, Si, S, Ar and Ca Nuclei from Proton- to Neutron-Drip Lines

We have investigated the gross structural properties of Ne, Mg, Si, S, Ar and Ca nuclei, starting from the proton-drip line till the neutron drip-line. An axially deformed self-consistent relativistic mean-field approach is used. All possible shapes (prolate, oblate or spherical) are searched, using three sets of force parameter, the NL2, NL-SH and TM2. Agreement between the calculation and experiment is found to be good, particularly for the TM2 force parameters. We find a sizeable deformation of the neutron/proton-rich Ne and Mg isotopes near the drip lines. Also, deformations of nuclei at and near the spherical magic shell N=28 are found to be large, in agreement with experiments. The breaking/non-breaking of the spherical shell gap at N=28 is also observed, dependent on the choice of force parameters and pairing strength. A large number of cases of shape coexistence are identified. The effects of pairing strength on the calculated properties are also discussed.