Structure and dynamics of linear-chain αcluster in covariant density functional theory

Recent progress in the structure and dynamics of nuclear linear-chain a clusters within the framework of covariant density functional theory is reviewed. The covariant density functional theory does not a priori assume the existence of a clusters and provides a microscopic and self-consistent description of the corresponding linear-chain cluster structure. By combining the covariant density functional theory with the cranking model, the coherent effects ff ects of nuclear spin and isospin on the linear-chain cluster structure of carbon isotopes are revealed. Owing to the effects ff ects of the Coriolis term in the cranking covariant density functional theory, o orbitals show a reduction in energy with the rotational frequency and are occupied by valence neutrons, indicating that the linear-chain cluster structures are more feasible in fast-rotating neutron-rich nuclei. A similar mechanism exists for the 3a a and 4a a linear-chain cluster structures in proton-rich nuclei, wherein protons occupy o orbitals at lower angular momenta than those observed for neutrons. Based on the calculations of the covariant density functional theory in a three-dimensional lattice space, the linear-chain cluster configuration in L2 C is shown as a state with the minimum energy on the potential energy surface for rotational frequencies of 2.0-3.5 MeV, thereby demonstrating the stability of the linear-chain cluster structure against nuclear bending motion and fission. Furthermore, the development of the time-dependent covariant density functional theory enables the dynamical study of the linear-chain cluster structure. Investigations of the microscopic dynamics of the linear-chain cluster states for L2 C and L4 C isotopes in the reactions 4 He + 8 Be and 4 He + L0 Be show that the dynamical isospin effects ff ects by the valence neutrons impede the longitudinal oscillations of clusters, thereby prolonging the lifetime of the linear-chain cluster states.