Heavy-ion collisions and nuclear quasi-molecular states

The bonding potential between two 12C-ion has been extracted from the experimental energies through a well defined quantum mechanical procedure. The potential is found to have a long range of the order of 15fm. This long range carries the signature of strong prolate deformation of the ions developed during the course of collision. This is also compatible with the 7.65 MeVO+ state of 12C which has a structure of a linear chain of 3-α clusters. It is also known from the deep inelastic studies that, in the entrance channel oblate deformation is favoured and in the exit channel prolate deformation. Thus the mechanism of the quasi-molecular states which emerge from this study is that in 12C+12C collision, after the two nuclei come closer by overcoming the coulomb barrier or by subbarrier tunneling, they form a composite system. In the effort to separate, they undergo a strong prolate deformation and a broad Coulomb barrier is formed which inhibits separation. Hence they undergo rotation and vibration like a diatomic molecule and generate molecular resonance states. Finally they separate with restoration of original shape after a long time in the exit channel. (author). 7 figs., 2 tabs