Abstract
The Watson's multiple scattering theory is used to generate the first and second order optical potentials for nucleon-nucleus elastic scattering at intermediate energies, (90-1000 MeV). A coupled channels method is developed to study the Pauli and Medium Range correlations, by using the non-local second order optical potential. The scattering due to first order potential is compared to the two cases in which the second order optical potential, incorporating double scattering corrections, is generated by Pauli and Pauli plus Medium Range correlations. The results are significantly different for the angular distribution of protons, on Carbon-12, at lower energies. The effects of deformation in Carbon-12 target are approximately incorporated by using the second order potential. Cohen and Kurath's wavefunctions were used for Carbon-12. The strength of the second order potential is sensitive to the nucleon distribution among the 1p1/2 and 1p3/2 shells. This potential is found to be energy dependent, and its influence on elastic scattering becomes insignificant above 300 MeV projectile energy. The target deformation does not influence the proton-Carbon-12, elastic scattering angular distribution or absorption above this energy. Simple methods are used to include in the theory the finite range of the two body interactions, and the overall agreement with the data seems to improve. However fits to the data are not good, and some reasons for this are considered.