The optical potential in the Green's function approach

Utilizing the so-calledλ ⁰⁰-approximation the effective single-particle potential (“mass operator”) is investigated with respect to its energy and momentum dependence. For the nucleon-nucleon interaction a localS-wave potential matching the experimental phase shifts is used. The dispersion behaviour of the real and imaginary parts of the generalized optical potential is studied. The potential on the energy-shell is in satisfactory agreement with the phenomenological fits.