This paper is devoted to the study of elastic scattering processes with the use of nonlocal separable interactions. An explicit and general expression for the transition amplitude has been given which includes Coulomb effects and possible excitation of the particles involved. As a first application of the formalism it is shown that a striking improvement of Mongan's results can be obtained in $p-p$ elastic scattering just by including Coulomb effects at low energy. We have then studied the nucleon-$\alpha$ elastic scattering below 50 MeV and the $\alpha -\alpha$ elastic scattering below 100 MeV, and the results obtained are in very good agreement with experimental data.

• Received 11 January 1971

DOI:https://doi.org/10.1103/PhysRevC.4.704