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

The excitation functions for 7Li+28Si quasielastic scattering at 150\ub0 and 170\ub0 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 6Li+28Si 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 6Li+28Si and 7Li+28Si, 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