Full-folding model calculations of proton elastic scattering at intermediate energy made using the free off-shell NN t matrix and including the variation of the energy in the NN center of mass as prescribed by the full-folding model are compared with similar calculations using t matrices evaluated at a fixed energy. The fixed energy is chosen on the basis of the incident beam energy ignoring the Fermi momentum of the struck target nucleon. Near 200 MeV, the energy prescription for the NN matrix is found to be responsible for much of the difference between recently reported full-folding calculations as well as for the differences between full-folding calculations and conventional tρ approximations to them. The sensitivity of the scattering observables to the starting energy suggests that at lower intermediate energies, explicit medium corrections should be included in applications of the full-folding model.

• Received 9 January 1991

DOI:https://doi.org/10.1103/PhysRevC.43.2734