  The real part of the optical potential for the nucleon-nucleus scattering at
lower energies (E_i<100MeV) has been calculated including nucleonic and mesonic
form factors by a double folding approach. Realistic density- and
energy-dependent effective NN-interactions DDM3Y, BDM3Y and HLM3Y based on the
Reid and Paris potentials are used in this respect. The effects of the nucleon
density distribution and the average relative momentum on the folded potential
have been analysed. A good agreement with the phenomenological potential of
Lagrange-Lejeune, as well as with the parametrization of
Jeukenne-Lejeune-Mahaux for both neutron and proton double-folded potentials is
obtained. The results indicate that the strongly simplified model interactions
used in preequilibrium reaction theory neglect important dynamical details of
such processes.
