Relativistic Coulomb excitation at small impact parameters
  The semiclassical model of relativistic Coulomb excitation is studied in situations in which the impact parameter is small enough so that projectile and target charge distributions overlap. The electromagnetic effects of this overlap are shown to be small. Realistic nucleon-nucleon reaction cross-sections, and realistic nuclear radial charge and matter distributions are used to determine a formula for the lower impact parameter limit to be used in the calculation of the Coulomb excitation cross-section. A wide selection of projectile-target pairs is explored, in the bombarding energy range of 1 GeV to 5 GeV per nucleon. 
B.F. Bayman and F. Zardi