Molecular-orbital structure in Be isotopes

The structure of 12Be is investigated using a microscopic α+α+4n model based on the molecular-orbit (MO) model. It is shown that the remark-able α-clustering and the contribution of the spin-orbit interaction make the binding of the state with the (3/2−)2(1/2+)2 configuration for the valence neutrons properly stronger in comparison with the closed p-shell (3/2−)2(1/2−)2 configuration. The molecular-like structure of the C isotopes is also investigated using a microscopic α+α+α+n+n+... model.