Abstract: The nucleus is described as a system of A nucleons interacting via the exchange of different mesons in covariant density functional theory (CDFT). This is state-of-the-art relativistic version of density functional theory.
I will start my presentation from basic features of the CDFT. Then, the results of systematic global investigation of differential charge radii within the CDFT framework will be presented. Absolute differential radii of different isotopic chains and their relative properties are well described in model calculations in the cases when the mean-field approximation is justified. The role of beyond-mean-field correlations in the description of odd-even staggering (OES) of charge radii will also be discussed. A new mechanism in which the fragmentation of the single-particle content of the ground state in odd-mass nuclei due to particle-vibration coupling provides a significant contribution to OES in charge radii has been suggested. The role of single-particle structure and its competition with Coulomb interaction in the creation of bubble nuclear shapes in light neutron-rich and superheavy nuclei will be discussed.
The detailed investigation of new physical mechanisms which allow to extend the boundaries of particle-bound nuclear landscape beyond the traditional limits has been performed over recent years. In the region of hyperheavy Z > 126 nuclei, the transition from ellipsoid-like nuclear shapes to toroidal ones provides a substantial increase of nuclear landscape. An extension of nuclear landscape is also feasible in lighter nuclei but it is driven by the rotation of the nuclei: rotational bands which are proton/neutron unbound at zero or low spins can be transformed into proton/neutron bound ones by collective rotation of nuclear systems. Strong Coriolis interaction acting on high-N intruder orbitals is responsible for this transformation. This new physical mechanism leads also to a new phenomenon of the formation of giant proton halos in rotating proton-rich nuclei which is triggered by the occupation of high-N intruder proton orbitals.