Fission Barriers at the End of the Chart of Nuclides

P. Möller, A. J. Sierk, T. Ichikawa, A. Iwamoto, M. Mumpower

Phys. Rev C 91 024310 (2015)

We present calculated fission-barrier heights for 5239 nuclides, for all nuclei between the proton and neutron drip lines with $171 \le A \le 330$. The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop model with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than five million different shapes, defined by five deformation parameters in the three-quadratic-surface shape parameterization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid ($\epsilon$) and in the spherical-harmonic ($\beta$) parameterizations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the $\epsilon-\gamma$ parameterization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about one MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative, and when possible, quantitative agreement and/or consistency with data on $\beta$-delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. These studies all indicate that the model is realistic at considerable distances from the region of nuclei where its parameters were determined.