Semi-microscopic description of the double backbending in some deformed even–even rare earth nuclei

Abstract

A semi-microscopic model to study the neutron- and proton-induced backbending phenomena in some deformed even–even nuclei from the rare earth region is proposed. The space of particle–core states is defined by the angular momentum projection of a quadrupole deformed product state. The backbending phenomena are described by mixing four rotational bands, defined by a set of angular momentum projected states, and a model Hamiltonian describing a set of paired particles moving in a deformed mean field and interacting with a phenomenological deformed core. The ground band corresponds to the configuration where all particles are paired, while the other rotational bands are built on one neutron or/and one proton broken pair. Four rare earth even–even nuclei which present the second anomaly in the observed moments of inertia are successfully treated within the proposed model.