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

We investigate refractive phenomena of the 16O+16O system at Elab=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 16O nucleus, we employ the orthogonal condition model based on the microscopic α+12C cluster picture. We perform coupled-channels calculations that include both the 31- (Eex=6.13 MeV) and the 11- (Eex=7.12 MeV) excitations of the 16O 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 Elab=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 16O+16O system. (author)