Coupled-channels study of the nuclear rainbow phenomena for the 16O-16O system

We investigate refractive phenomena of the O-16+O-16 system at E-lab = 124, 145, 250 and 350 MeV using the microscopic coupled-channels method. The coupling potentials are constructed by the double folding model using the three effective nucleon-nucleon interactions, M3Y, DDM3Y-ZR and DDM3Y-FR (DDM3Y1). With respect to the transition density matrix elements of the O-16 nucleus, we employ the orthogonal condition model based on the microscopic alpha+C-12 cluster picture. We perform coupled-channels calculations that include both the 3(1)(-) (E-ex = 6.13 MeV) and the 1(1)(-) (E-ex = 7.12 MeV) excitations of the O-16 nucleus. We show that the characteristic features of the nuclear rainbow phenomena can be reproduced successfully by our coupled-channels calculations with the DDM3Y-FR folding potential. The absolute values of the experimental cross sections for inelastic scattering at E-lat, = 350 MeV can also be reproduced by our calculation. The coupling effects from inelastic channels are mainly absorptive and weakly repulsive in the refractive phenomena at these energies in the O-16+O-16 system.