Scission configuration in the self-consistent calculations with neck constraint

TL;DR

This paper demonstrates that using multi-constraint calculations with a neck constraint results in a smooth potential energy surface during nuclear fission, revealing insights into neck properties and alternative fission pathways.

Contribution

It introduces a method to avoid discontinuities at scission in fission calculations by applying multi-constraints, and analyzes neck properties in different fission modes.

Findings

No discontinuity in potential energy surface at scission with multi-constraint approach.

Early neck rupture can occur at lower deformation parameters.

Neck radius cannot decrease below 2 fm in asymmetric fission mode.

Abstract

The calculations of the potential energy surface are essential in the theoretical description of the fission process. In the constrained self-consistent approach, the smooth evolution of nuclear shape is described from the ground state until a very elongated one with a narrow neck. In all microscopic calculations, the rupture of the neck at scission is associated with a substantial change of nuclear matter density distribution and rapid energy decrease. In this paper, we show that there is no discontinuity of the potential energy surface at scission when multi-constrained calculations are applied with the neck constraint. An early rupture of the neck at lower quadrupole and octupole moments is discussed as competitive with the conventional fission path. We discuss the neck properties in the scission configuration. We find that the neck radius in the asymmetric fission mode cannot decrease below 2 fm, and the nuclear matter density cannot decrease below the saturation density. In the compact fission mode, nuclear density may go down to half of the saturation density before the rupture of the neck.