New atomic mass differences and mass systematics in the region 100 ≦ N ≦ 126

Abstract

Values are reported for ten atomic mass differences involving isotopes of W, Re and Os. The new mass differences are combined with existing nuclear reaction and decay data to yield single- and double-neutron separation energies and neutron pairing energies for many nucleides in this mass region. The neutron separation energy systematics defined by the nucleides between Hf and Pb indicate that the transition from permanently deformed nuclei at N ≈ 110 to spherical nuclei at N ≈ 120 is not accompanied by a pronounced mass effect.