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

摘要

Storage-ring mass spectrometry was applied to neutron-rich $^{197}$Auprojectile 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. Theuncertainty of previously known masses of $^{189,190}$W and $^{195}$Os nucleiwas improved. Observed irregularities on the smooth two-neutron separationenergies for Hf and W isotopes are linked to the collectivity phenomena in thecorresponding nuclei.