Static Fission Properties of Even-Even Actinides within the Warsaw Macroscopic-Microscopic Model Using Fourier-over-Spheroid Parameterization

TL;DR

This study systematically analyzes fission barrier heights and static properties of even-even actinides using a comprehensive five-dimensional shape parameterization within the Warsaw macroscopic-microscopic model, achieving high accuracy and detailed potential energy landscapes.

Contribution

It introduces a large deformation grid and a refined shape parameterization to improve the exploration of fission barriers in actinides, including the analysis of hyperdeformed minima.

Findings

Barrier heights agree with empirical data within 1 MeV

A shallow third minimum is observed in Th isotopes

No third minimum is found in heavier actinides like U and Pu

Abstract

A systematic study of fission barrier heights and static properties of even-even actinide nuclei from Th to Cf has been performed within the Warsaw macroscopic-microscopic model using the five-dimensional Fourier-over-Spheroid (FoS) shape parameterization. The use of a large deformation grid, containing about $1.3\times10^{8}$ points for each nucleus, allows for a refined and numerically complete exploration of the potential energy landscape without dividing the configuration space into subregions or applying interpolation. Barrier heights, extracted via the Immersion Water Flow method, show good agreement with empirical evaluations (including the new IAEA RIPL-4 dataset) with mean deviations below 1 MeV. Special attention is given to the long-debated third, hyperdeformed minimum. For Th isotopes, a shallow but distinct third well appears, whereas it's absent in heavier actinides (U, Pu).