Probing the potential and reaction coupling effects of (6,7)Li+(28)Si at sub- and near-barrier energies with elastic backscattering

The excitation functions for (7)Li + (28)Si quasielastic scattering at 150 degrees and 170 degrees have been measured at sub- and near-barrier energies (0.6 to 1.3 VB) and the corresponding barrier distributions derived. The results were analyzed within the framework of the optical model using a procedure similar to one used on previous results for (6)Li + (28)Si employing double-folded potentials calculated using the BDM3Y1 effective interaction. The variation of the surface strength of the optical potential as a function of incident energy was compared for the two systems (6)Li + (28)Si and (7)Li + (28)Si, the barrier distributions being used to help better define the potential at the lowest energies. The barrier distributions were also analyzed with continuum-discretized coupled-channel (CDCC) and coupled reaction channel (CRC) calculations as a means of investigating the influence of breakup and transfer reactions on these quantities for these light, weakly bound projectiles. Physical Review C