Nuclear structure of N = 86 isotones of Ce, Nd, Sm and Gd

Abstract

The collectivity in the low-energy spectra of N = 86 isotones of Ce, Nd, Sm and Gd is studied vis-a-vis their vibrational band structure. The energy level pattern and the E2 transition rates are compared with the predictions of the microscopic dynamic pairing plus quadrupole model plus 5DCH (Bohr-Mottelson view). The role of the Z = 64 subshell in the increase of ground band level energies with increasing Z , and the different effects on the B(E2) values are illustrated. The subshell energy gap versus the occupation of Nilsson single-particle orbits is discussed. A brief discussion of the different current microscopic collective models is also given.