Collective Models

Abstract

Abstract While the static moments of nuclei located close to the major shell closures are well described by the independent particle model (with core polarization and meson-exchange current corrections) nuclei further away from shell closures are characterized by non-spherical shapes and large quadrupole moments. To give a quantitative discussion of such nuclei will require a more phenomenological approach. It will be necessary to introduce some collective variables to describe cooperative modes of motion and a few intrinsic variables to describe the few extra-core nucleons not participating in the collective motion. Any coupling between the collective and intrinsic variables is taken as weak and studied through perturbation theory. Collective variables are only useful if the energy Hamiltonian can be separated into terms that depend on the collective variables and terms that do not. Then the eigenstates are of product form.