Shape transition and coexistence in Te isotopes studied with the quadrupole collective Hamiltonian based on a relativistic energy density functional

Evolution and coexistence of shape and the related spectroscopic properties of even-even Te isotopes are investigated within the quadrupole collective model that is based on the nuclear density functional theory. By means of the constrained self-consistent mean-field calculations performed within the relativistic Hartree-Bogoliubov method with a choice of the energy density functional and pairing interaction, the deformation-dependent mass parameters and moments of inertia as well as collective potential of the triaxial quadrupole collective Hamiltonian are completely determined. The collective model produces for the near mid-shell nuclei, e.g., $^{116}$Te and $^{118}$Te, the low-energy $0^+_2$ state, which can be interpreted as the intruder state originating from the strongly deformed prolate minimum in the potential energy surface, along with the $0^+_1$ ground state that is attributed to the normal state based on a weakly oblate deformed global minimum. The collective model calculation suggests a parabolic behavior of the $0^+_2$ energy level near the neutron mid-shell $N=66$, as observed experimentally. Sensitivities of the calculated low-energy spectra to the pairing strength and collective mass parameters are analyzed.