Superdeformation and clustering inCa40studied with antisymmetrized molecular dynamics

Abstract

Deformed states in $^{40}\mathrm{Ca}$ are investigated with a method of antisymmetrized molecular dynamics. Above the spherical ground state, rotational bands arise from a normal deformation and a superdeformation as well as an oblate deformation. The calculated energy spectra and $E2$ transition strengths in the superdeformed band reasonably agree to the experimental data of the superdeformed band starting from the ${0}_{3}^{+}$ state at 5.213 MeV. By the analysis of single-particle orbits, it is found that the superdeformed state has particle-hole nature of an $8p\text{\ensuremath{-}}8h$ configuration. One of new findings is parity asymmetric structure with $^{12}\mathrm{C}+^{28}\mathrm{Si}$-like clustering in the superdeformed band. We predict that $^{12}\mathrm{C}+^{28}\mathrm{Si}$ molecular bands may be built above the superdeformed band due to the excitation of intercluster motion. They are considered to be higher nodal states of the superdeformed state. We also suggest negative-parity bands caused by the parity asymmetric deformation.