A cluster-rotor-coupling approach to the backbending in rare earth nuclei

Abstract

Opposite to the strong-coupling scheme, in which the back bending effect is discussed as an effect of the Coriolis force in the rotating body fixed frame, we have studied the effect in lab coordinates, in which a Coriolis force does not exist. For this purpose exact solutions of the ( i 13 2 ) N ν problem have been weakly coupled to a rigid rotor core spectrum. In addition to the usual quadrupole coupling also a pairing type interaction was included, which allows for the exchange of neutron pairs between the core and the valence system. It was found that this pairing field has drastic effects on the results and should hence not be neglected.