Microscopic Study of Coexistence of Alpha-Cluster and Shell-Model Structure in the 40Ca-44Ti Region

Abstract

The structure of the nuclei in the mass range 40 ≤ A ≤ 44 is investigated by the microscopic α + core orthogonality condition model. The energy spectra, electromagnetic transitions and α-spectroscopic factors are calculated. The calculated properties are in good overall agreement with the available experimental data. It is shown that the α-cluster states yield similar rotational bands which are characterized by the weak coupling feature and parity-doublet. The observed E2 intra-band transitions in the cluster bands, which show strong enhancement, and other transitions are systematically reproduced by the model. The model also gives a good account for enhancement and spreading of the α-spectroscopic factors. It is discussed that the coexistence and interference of α-cluster states and shell-model states are important for understanding these features of the nuclei.