We present a closed expression for the exact deuteron (H
3, He
3) optical potential in terms of higher point Green functions. This form is well suited to study its energy dependence. Intermediate resonances due to two (three) particle phonon coupling are suggested and the coupling constants are identified with the Migdal parameters.
I would like to thank Prof. H. J. Mang and Prof. W. Brenig for stimulating discussions and Dr. S. Ethofer for very useful remarks concerning the formalism.