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 $S_{\mathrm{2n}}$), root-mean-square radii of matter ($R_m$), of neutron ($R_n$), of proton ($R_p$) and of charge ($R_c$) distributions, Fermi surfaces ($\lambda$), ground-state spins ($J$) and parities ($\pi$). 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 $S_n$, $S_{\mathrm{2n}}$, 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 $8\le Z\le 110$ 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.