Three-dimensional potential energy surface for fission of ²³⁶U within covariant density functional theory*

Abstract

We have calculated the three-dimensional potential energy surface (PES) for the fission of compound nucleus 236U using the covariant density functional theory with constraints on the axial quadrupole and octupole deformations (β2, β3) as well as the nucleon number in the neck q N. By considering the additonal degree of freedom q N, coexistence of the elongated and compact fission modes is predicted for 0.9≤ β3≤1.3. Remarkably, the PES becomes very shallow across a large range of quadrupole and octupole deformations for small q N, and consequently, the scission line in (β2, β3) plane will extend to a shallow band, which leads to a fluctuation for the estimated total kinetic energies by several to ten MeV and for the fragment masses by several to about ten nucleons.