Cluster structures and superdeformation inSi28

Abstract

We have studied positive-parity states of 28 Si using antisymmetrized molecular dynamics and multiconfiguration mixing with constrained variation. Applying constraints to the cluster distance and the quadrupole deformation of the variational calculation, we have obtained basis wave functions that have various structures such as α- 24 Mg and 12 C- 16 O cluster structures as well as deformed structures. Superposing those basis wave functions, we have obtained a oblate ground-state band, a β vibration band, a normal-deformed prolate band, and a superdeformed band. It is found that the normal-deformed and superdeformed bands contain large amounts of the 12 C- 16 O and α- 24 Mg cluster components, respectively. The results also suggest the presence of two excited bands with the developed α- 24 Mg cluster structure, where the intercluster motion and the 24 Mg-cluster deformation play important roles.