The imaginary part of the nucleon-nucleus optical potential

Volume integrals of the imaginary part of the proton and the neutron optical potentials obtained from the existing phenomenological analyses for the mass number range of 12-209 and for a range of nucleon energies (Esub(p)=10-180 MeV, Esub(n)=8-150 MeV) have been fitted with an empirical expression. The isoscalar, the isovector and the Coulomb components determined empirically have been compared with those obtained from the microscopic approach. Though there is qualitative agreement between the two predictions, there are differences when compared qualitatively. (orig.)