Isotopic dependence of fission threshold in nuclei with Z=114 and Z=120

Abstract:

Potential energy surfaces of superheavy nuclei are investigated within the multidimensionally-constrained relativistic mean-field model. The results are analysed using the Strutinsky shell correction method, with particular emphasis on ²⁹⁶Lv and isotopic chains of Z=114 and Z=120. The analysis reveals that triaxial degrees of freedom substantially reduces the barrier height along the triaxial fission pathway compared to the axial fission path in ²⁹⁶Lv. A step-like behaviour emerges in proton shell corrections for Z=114 isotopes, contrasting with the smoother patterns observed in Z=120 isotopes, is attributed to the differences in the ground-state deformations. The observed correlation between fission barrier maxima and shell correction minima points to the shell closures at neutron numbers N=172 and N=184 at Z=114 and 120.