Abstract
Atomic masses of the neutron-rich isotopes , , , , and have been measured with high precision using the Penning trap mass spectrometer JYFLTRAP at the IGISOL facility. The masses of , , , and were measured for the first time. These new data represent a major improvement in the knowledge of the masses in this neutron-rich region. Two-neutron separation energies provide evidence for the reduction of the shell gap energy towards germanium () and a subsequent increase at gallium (). The data are compared with a number of theoretical models. An indication of the persistent rigidity of the shell gap towards nickel () is obtained.
- Received 20 March 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.052502
©2008 American Physical Society