Shape evolution in the neutron-rich tungsten region

Recent experimental data on the low-lying states in 190W show a change in the E(41 )/E(2 + 1 ) behavior compared to less neutron-rich neigbors. Self-consistent axially-deformed Hartree-Fock calculations, using a separable monopole interaction, of nuclei in the vicinity of 190W are performed to systematically examine the evolution of ground state quadrupole deformations. It is found that the neutron number N = 116 causes a coexistence of oblate and prolate shapes, with a weak dependence on proton number, thereby hindering the development of these isotones as well-deformed rotors.