THE INFLUENCE OF GIANT-RESONANCES ON THE PRODUCTION OF DELTA-ELECTRONS IN HEAVY-ION COLLISIONS

Recently measured delta-electron spectra from elastic U + Pd-collisions at 6.1 MeV/u show for small impact parameters enhancements up to two orders of magnitude relative to coupled-channel calculations which describe delta-electron production for larger impact parameters almost perfectly. If these deviations are interpreted as due to modified nuclear trajectories they imply most interesting structures of the internuclear potential at the Coulomb-barrier. We show that an alternative explanation, namely an delta-electron enhancement due to strong collective nuclear excitations, e.g. giant resonances, does not reproduce the experimental finding.