Effects of rotation and valence nucleons in molecular α-chain nuclei

Effects of rotation and valence nucleons in molecular linear alpha-chain nuclei are analyzed using a three-dimensional lattice cranking model based on covariant density functional theory. The structure of the mirror nuclei C-16 and Ne-16 is investigated as a function of rotational frequency. The valence nucleons, with respect to the 3 alpha linear chain core of C-12, at low frequency occupy the pi molecular orbital. With increasing rotational frequency these nucleons transition from the pi orbital to the sigma molecular orbital, thus stabilizing the 3 alpha linear chain structure. It is predicted that the valence protons in Ne-16 change occupation from the pi to the sigma molecular orbital at (h) over bar omega approximate to 1.3 MeV, a lower rotational frequency compared to (h) over bar omega approximate to 1.7 MeV for the valence neutrons in C-16. The same effects of valence protons are found in Mg-20, compared to the four valence neutrons in O-20. The model is also used to examine the effect of alignment of valence nucleons on the relative positions and size of the three alpha clusters in the mirror nuclei C-16 and Ne-16.