Schottky mass measurements of heavy neutron-rich nuclides in the element range $70\leZ \le79$ at the ESR

TL;DR

This study used storage-ring mass spectrometry to measure and improve the masses of neutron-rich heavy nuclei in the element range 70 to 79, revealing irregularities linked to nuclear collectivity.

Contribution

First-time mass measurements of several neutron-rich isotopes and improved mass data for others, enhancing understanding of nuclear structure in this region.

Findings

Measured new masses of $^{181,183}$Lu, $^{185,186}$Hf, $^{187,188}$Ta, $^{191}$W, $^{192,193}$Re.

Improved mass uncertainties for $^{189,190}$W and $^{195}$Os.

Detected irregularities in two-neutron separation energies related to nuclear collectivity.

Abstract

Storage-ring mass spectrometry was applied to neutron-rich $^{197}$Au projectile fragments. Masses of $^{181,183}$Lu, $^{185,186}$Hf, $^{187,188}$Ta, $^{191}$W, and $^{192,193}$Re nuclei were measured for the first time. The uncertainty of previously known masses of $^{189,190}$W and $^{195}$Os nuclei was improved. Observed irregularities on the smooth two-neutron separation energies for Hf and W isotopes are linked to the collectivity phenomena in the corresponding nuclei.