Onset of nuclear structure effects in near-barrier elastic scattering of weakly bound nuclei: 6He and 6Li compared

The elastic scattering of the halo nucleus 6He from heavy targets at incident energies near the Coulomb barrier displays a marked deviation from the standard Fresnel-type diffraction behavior. This deviation is due to the strong Coulomb dipole breakup coupling produced by the Coulomb field of the heavy target, a specific feature of the nuclear structure of 6He. We have performed Continuum Discretized Coupled Channels calculations for the elastic scattering of 6He and 6Li from 58Ni, 120Sn, 144Sm, 181Ta and 208Pb targets in order to determine the range of ZT where this nuclear-structure specific coupling effect becomes manifest. We find that the strong Coulomb dipole breakup coupling effect is only clearly experimentally distinguishable for targets of ZT≅80.