Microscopic description of fission in nobelium isotopes with the Gogny-D1M energy density functional

TL;DR

This paper uses Gogny-D1M energy density functional within mean-field models to systematically study fission properties and lifetimes of nobelium isotopes, including both even-even and odd-mass nuclei.

Contribution

It provides a comprehensive microscopic analysis of fission in nobelium isotopes using advanced self-consistent methods and accounts for effects specific to odd-mass nuclei.

Findings

Odd-mass nuclei have larger spontaneous fission half-lives than even-even neighbors.

The Gogny-D1M functional accurately reproduces alpha decay energies and lifetimes.

Fission barriers and other properties are systematically characterized across isotopes.

Abstract

Constrained mean-field calculations, based on the Gogny-D1M energy density functional, have been carried out to describe fission in the isotopes $^{250-260}$No. The even-even isotopes have been considered within the standard Hartree-Fock-Bogoliobov (HFB) framework while for the odd-mass ones the Equal Filling Approximation (HFB-EFA) has been employed. Ground state quantum numbers and deformations, pairing energies, one-neutron separation energies, inner and outer barrier heights as well as fission isomer excitation energies are given. Fission paths, collective masses and zero-point quantum vibrational and rotational corrections are used to compute the systematic of the spontaneous fission half-lives t$_\mathrm{SF}$ both for even-even and odd-mass nuclei. Though there exists a strong variance of the predicted fission rates with respect to the details involved in their computation, it is shown that both the specialization energy and the pairing quenching effects, taken into account within the self-consistent HFB-EFA blocking procedure, lead to larger t$_\mathrm{SF}$ values in odd-mass nuclei as compared with their even-even neighbors. Alpha decay lifetimes have also been computed using a parametrization of the Viola-Seaborg formula. The high quality of the Gogny-D1M functional regarding nuclear masses leads to a very good reproduction of $Q_{\alpha}$ values and consequently of lifetimes.