Molecular-orbital structure in neutron-rich C isotopes - art. no. 014301

The moleculelike structure of the C isotopes (A = 12, 14, 16) is investigat ed using a microscopic alpha + alpha + alpha + n + n + ... model. The valen ce neutrons are classified based on the molecular-orbit model, and both pi orbit and sigma orbit are introduced around three alpha clusters. The valen ce neutrons which occupy the pi orbit increase the binding energy and stabi lize the linear chain of 3 alpha against the breathinglike breakup. However , C-14 With the pi orbit does not show a clear energy minimum against the b endinglike path. The combination of the valence neutrons in the pi and sigm a orbits is promising to stabilize the linear-chain state against the breat hing and bending modes, and it is found that the excited states of C-16 wit h the (3/2(pi)(-))(2)(1/2(sigma)(-))(2) configuration for the four valence neutrons is one of the most promising candidates for such a structure.