Semi-microscopic description of the backbending phenomena in some deformed even-even nuclei

摘要

The mechanism of backbending is semi-phenomenologically investigated based onthe hybridization of two rotational bands. These bands are defined by treatinga model Hamiltonian describing two interacting subsystems: a set of particlesmoving in a deformed mean field and interacting among themselves through aneffective pairing force and a phenomenological deformed core whose intrinsicground state is an axially symmetric coherent boson state. The two componentsinteract with each other by a quadrupole-quadrupole and a spin-spininteraction. The total Hamiltonian is considered in the space of states withgood angular momentum, projected from a quadrupole deformed product function.The single-particle factor function defines the nature of the rotational bands,one corresponding to the ground band in which all particles are paired andanother one built upon a $i_{13/2}$ neutron broken pair. The formalism isapplied to six deformed even-even nuclei, known as being good backbenders.Agreement between theory and experiment is fairly good.