Mean field calculations of nucleon-nucleus scattering

Corrections to the first order term of the multiple scattering expansion of the nucleon-nucleus optical potential due to the propagation of the projectile nucleon in the target nucleus mean field are estimated. The effects of nonlocalities of the nucleon-nucleon transition amplitude are included. Calculations are performed for nucleon scattering from {sup 16}O and {sup 208}Pb at 100, 200, and 400 MeV incident energies. We show that the mean field effect is repulsive and reduces the strength of the local representation of the impulse approximation potential by approximately 25{percent} in the nuclear interior. {copyright} {ital 1996 The American Physical Society.}