Octupole deformation in the ground states of even-even nuclei: a global analysis within the covariant density functional theory
Abstract
A systematic investigation of octupole deformed nuclei is presented for even-even systems with Z≤ 106 located between the two-proton and two-neutron drip lines. For this study we use five most up-to-date covariant energy density functionals of different types, with a non-linear meson coupling, with density dependent meson couplings, and with density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov (RHB) theory based on an effective separable particle-particle interaction of finite range. This allows us to assess theoretical uncertainties within the present covariant models for the prediction of physical observables relevant for octupole deformed nuclei. In addition, a detailed comparison with the predictions of non-relativistic models is performed. A new region of octupole deformation, centered around Z 98, N 196 is predicted for the first time. In terms of its size in the (Z,N) plane and the impact of octupole deformation on binding energies this region is similar to the best known region of octupole deformed nuclei centered at Z 90, N 136. For the later island of octupole deformed nuclei, the calculations suggest substantial increase of its size as compared with available experimental data.