Further microscopic studies of the fission barriers of heavy nuclei

TL;DR

This paper investigates two key sources of error in microscopic calculations of fission barrier heights in heavy nuclei, specifically the Coulomb exchange approximation and parity projection, showing their impact on barrier height estimations.

Contribution

It identifies and quantifies the effects of Coulomb exchange treatment and parity projection approximations on fission barrier height calculations.

Findings

Approximate Coulomb exchange treatment underestimates barrier heights by a few hundred keV.

Unprojected solutions lead to similar underestimations of fission barriers.

Correcting these approximations improves the accuracy of microscopic fission barrier evaluations.

Abstract

Two systematic sources of error in most current microscopic evaluations of fission-barrier heights are studied. They are concerned with an approximate treatment of the Coulomb exchange terms (known as the Slater approximation) in the self-consistent mean fields and the projection on good parity states (e.g., of positive parity for the spontaneous fission of an even-even nucleus) of left-right reflection asymmetric intrinsic solutions (e.g., around the second barrier). Approximate or unprojected solutions are shown to lead each to an underestimation of the barrier heights by a few hundred keV.