Quasielastic scattering of Li and Be on 12C

The quasielastic 11Li, 12Be + 12C scattering at E/A = 60 MeV has been studied by adding a fitted polarisation potential to the folding model potential derived from 9Li, 12Be - 12C and neutron-12C phenomenological optical potentials. For 11Li + 12C scattering we have required that our potentials reproduce simultaneously quasielastic data, reaction and break-up cross sections with a polarisation potential satisfying the global properties derived theoretically by several authors. We have shown that an overall agreement is achieved if the Li wave function has a large (2s)2 two-neutron component and only in this case. For a 12Be projectile we were able to reproduce the quasielastic data with reasonable reaction cross section and polarisation potential. However, when a similar analysis has been performed for 11Li+ 28Si scattering at E/A = 29 MeV we have failed to explain the data.