Refinements of the nucleon-exchange transport model for the emission of hard photons and nucleons

A previously developed nucleon-exchange transport model for preequilibrium neutron and hard photon emission is extended to include proton emission. Several refinements including diffuse ground-state nucleonic momentum distributions and quantal rather than classical bremsstrahlung production are added. The incorporation of a diffuse momentum distribution improves the reproduction of experimental spectra and multiplicities, particularly at low bombarding energies. Quantal bremsstrahlung enhances the production of high-energy photons. The effect of deceleration of the colliding nuclei during the propagation of the jetting particles through the receptor nucleus is explored. The effect of preequilibrium emission on the evaporation residue and its dependence on entrance channel mass asymmetry is studied. The number of preequilibrium particles emitted is inconsistent with some previous analyses of evaporation residue spectra