Abstract
The real parts of the alpha alpha and alpha-nucleus potential, particularly for Ca-40,Ca-44,Ca-48 and Ni-58 targets are determined from a realistic two-nucleon potential using an energy-density functional approach and axe found to be non-monotonic with a short range repulsion in their functional forms that axe similar to those needed in accounting for elastic scattering data. The deduced alphaalpha potential has no bound states and the calculated decay width of Be-8 of about 6.4 eV at about 200 keV energy is in agreement with the measurement.