Microscopic study on asymmetric fission dynamics of 180Hg within covariant density functional theory

The asymmetric fission dynamics of 180Hg has been analyzed in the framework of the time-dependent generator coordinate method (TDGCM) based on covariant density functional theory (CDFT) with the relativistic PC-PK1 functional. Three-dimensional (f32, f33, qN) constrained CDFT calculations have been performed to determine the scission configurations. Remarkably, an asymmetric fission valley is observed in the potential energy surface in the f32-f33 plane and the heavy/light fragments at scission are 101Rh/79Br, in good agreement with the data. Furthermore, we find that the heavy fragments of lowest-energy scission configurations, compared to those of other scission points, have rather small quadrupole deformations (f32 - 0.4) and certain octupole deformations (f33 - 0.3-0.4), which are driven by the extended neutron octupole shell gap with N = 56. Based on the scission configurations, the estimated total kinetic energy distribution is consistent with the trend of experimental data. Finally, the dynamical TDGCM calculation reproduces the asymmetric yield distribution of the low-energy fission of 180Hg, especially for the peak positions.

Automated summary

The asymmetric fission dynamics of 180Hg has been studied using the time-dependent generator coordinate method (TDGCM) based on covariant density functional theory (CDFT). The results show that there is an asymmetric fission valley in the potential energy surface, and the heavy/light fragments at scission are 101Rh/79Br, consistent with experimental data. It is also found that the heavy fragments of lowest-energy scission configurations have small quadrupole deformations and certain octupole deformations, driven by the extended neutron octupole shell gap. The estimated total kinetic energy distribution is in agreement with experimental data. The dynamical TDGCM calculation successfully reproduces the asymmetric yield distribution of low-energy fission of 180Hg, particularly the peak positions.