From cluster structures to nuclear molecules: The role of nodal structure of the single-particle wave functions

Abstract

The nodal structure of the density distributions of the single-particle states occupied in rod-shaped, hyperand megadeformed structures of nonrotating and rotating N ∼ Z nuclei has been investigated in detail. The single-particle states with theNilsson quantum numbers of the [NN0]1/2 (withN from 0 to 5) and [N,N − 1,1] (with N from 1 to 3 and = 1/2, 3/2) types are considered. These states are building blocks of extremely deformed shapes in the nuclei with mass numbers A 50. Because of (near) axial symmetry and large elongation of such structures, the wave functions of the single-particle states occupied are dominated by a single basis state in cylindrical basis. This basis state defines the nodal structure of the single-particle density distribution. The nodal structure of the single-particle density distributions allows us to understand in a relatively simple way the necessary conditions for α clusterization and the suppression of the α clusterization with the increase of mass number. It also explains in a natural way the coexistence of ellipsoidal mean-field-type structures and nuclear molecules at similar excitation energies and the features of particle-hole excitations connecting these two types of the structures. Our analysis of the nodal structure of the single-particle density distributions does not support the existence of quantum liquid phase for the deformations and nuclei under study.