Exciton Model Calculations up to 200 MeV: The Optical Model Points the Way

We present a preequilibrium model for nucleons with incident energies from 7 to 200 MeV, for nuclides in the mass range A ⩾ 24. This is accomplished by a new global approach for the two‐component exciton model which, together with the complementary compound and direct reaction mechanisms, enables a description of continuum energy spectra over the whole outgoing energy range. We develop new forms for the internal transition rates with collision probabilities based on a recent optical‐model potential. To connect with conventional semi‐classical analyses, we derive from this approach a new energy‐dependent form for the average square matrix element M². We include surface effects and multiple preequilibrium emission up to any order. To assess the predictive power of our model, we have tested it against a complete experimental database of (n,xn), (n,xp), (p,xn), and (p,xp) spectra. In this paper we will show some examples.