Collective Reactions in the Continuum

We show that pre-equlibrium inelastic scattering reactions to the continuum contain substantial collective components in addition to the multistep direct and multistep compound reactions. These collective reactions are investigated for the vibrational nuclei 56Fe, 58Ni, 90Zr, 93Nb, 208Pb and 209Bi , and the strongly-deformed, rotational W nucleus. The collective cross-sections are calculated using the experimental data for low-lying collective excitations supplemented where necessary by the giant multipole resonances evaluated using the energy-weight ed sum rule. The MSC and MSD cross-sections are evaluated by the Feshbach-Kerman-Koonin theory using a consistent set of parameters determined by analyses of (p, xn) reactions, that have practically no collective components. The results are compared with high-resolution neutron inelastic scattering data and prove able to account for the absolute magnitude of the cross-sections and also their detailed structure.