We present an optical model (OM) analysis of the elastic scattering data of
the reactions 6He+27Al and 6He+208Pb at incident energies around the Coulomb
barrier. The bare part of the optical potential is constructed microscopically
by means of a double folding procedure, using the Sao Paulo prescription
without any renormalization. This bare interaction is supplemented with a
Coulomb dipole polarization (CDP) potential, which takes into account the
effect of the dipole Coulomb interaction. For this CDP potential, we use an
analytical formula derived from the semiclassical theory of Coulomb excitation.
The rest of the optical potential is parametrized in terms of Woods-Saxon
shapes. In the 6He+208Pb case, the analysis confirms the presence of long range
components, in agreement with previous works. Four-body Continuum-Discretized
Coupled-Channels calculations have been performed in order to better understand
the features of the optical potentials found in the OM analysis. This study
searches to elucidate some aspects of the optical potential of weakly bound
systems, such as the dispersion relation and the long range (attractive and
absorptive) mechanisms.Comment: Accepted in Nucl. Phys. A; 26 pages, 8 figures, 6 tables