Nuclear ground-state properties probed by the relativistic Hartree–Bogoliubov approach

Using the relativistic Hartree–Bogoliubov approach with separable pairing force coupled with the latest point-coupling and meson-exchange covariant density functionals, i.e., PC-L3R, PC-X, DD-MEX, and DD-PCX, we systematically explore the ground-state properties of all isotopic chains from oxygen (Z=8) to darmstadtium (Z=110). These properties consist of the binding energies (E_b), one- and two-neutron separation energies (S_n and S_2n), root-mean-square radii of matter (R_m), of neutron (R_n), of proton (R_p) and of charge (R_c) distributions, Fermi surfaces (λ), ground-state spins (J) and parities (π). We then use these calculated properties to predict the edges of nuclear landscape and bound nuclei for the isotopic chains of Z = 8–110. The number of bound nuclei predicted by PC-L3R, PC-X, DD-MEX, and DD-PCX, are 9004, 9162, 7112, and 6799, respectively. These latest covariant density functionals produce a set of rather similar proton drip lines due to the strong repulsive Coulomb force shifting up the single-proton energy of the proton-rich nuclei. PC-L3R and PC-X estimate more extended borders of the neutron-rich region compared with the neutron drip lines estimated by DD-MEX, and DD-PCX. Meanwhile, the root-mean-square deviations of one- (two-) neutron separation energies yielded from PC-L3R, PCX, DD-MEX, and DD-PCX are 0.962 (1.300) MeV, 0.920 (1.483) MeV, 1.010 (1.544) MeV, and 0.993 (1.753) MeV, respectively. The deviations of theoretical S_n, S_2n, and charge radii from the available experimental ones increase at the regions further away from the proton magic numbers, indicating the important role of deformation in these regions. The root-mean-square deviations of charge radius distributions of comparing the available experimental values with the theoretical counterparts resulted from PC-L3R, PC-X, DD-MEX, and DD-PCX are 0.035 fm, 0.037 fm, 0.034 fm, and 0.035 fm, respectively. We compute and present the root-mean-square radii of neutron distributions for all isotopes of 8≤Z≤110 with respect to the empirical R_n. Basically, the systematic trends of the theoretical root-mean-square radii of neutron distributions generated from PC-L3R and PC-X closely follow the empirical R_n, except for the region of extreme neutron-rich nuclei, whereas DD-PCX produces a trend lower than the empirical R_n at the N<150 region. We notice pronounced differences between the empirical and theoretical R_n at nuclei near the neutron drip line of the Mg, Ca, and Kr isotopic chains, suggesting the possible existence of the halo or giant halo phenomena.