Covariant density functional theory input for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>r</mml:mi></mml:math>-process simulations in actinides and superheavy nuclei: The ground state and fission properties
A. Taninah, S. E. Agbemava, A. V. Afanasjev
Abstract
A systematic investigation of the ground-state and fission properties of even-even actinides and superheavy nuclei with $Z=90--120$ from the two-proton up to two-neutron drip lines with proper assessment of systematic theoretical uncertainties has been performed for the first time in the framework of covariant density functional theory (CDFT). These results provide a necessary theoretical input for the $r$-process modeling in heavy nuclei and, in particular, for the study of fission cycling. Four state-of-the-art globally tested covariant energy density functionals (CEDFs), namely, DD-PC1, DD-ME2, NL3*, and PC-PK1, representing the major classes of the CDFT models are employed in the present paper. Ground-state deformations, binding energies, two-neutron separation energies, $\ensuremath{\alpha}$-decay ${Q}_{\ensuremath{\alpha}}$ values and half-lives, and the heights of fission barriers have been calculated for all these nuclei. Theoretical uncertainties in these physical observables and their evolution as a function of proton and neutron numbers have been quantified and their major sources have been identified. Spherical shell closures at $Z=120, N=184$, and $N=258$ and the structure of the single-particle (especially, high-$j$) states in their vicinities as well as nuclear matter properties of employed CEDFs are two major factors contributing to theoretical uncertainties. However, different physical observables are affected in a different way by these two factors. For example, theoretical uncertainties in calculated ground-state deformations are affected mostly by the former factor, while theoretical uncertainties in fission barriers depend on both of these factors.