IONIZATION OF EXCITED HYDROGENIC ATOMS BY FAST ELECTRON IMPACT O. A. Fojon, R.D. Rivarola and C. Stia Instituto de Fisica Rosario (CONICET-UNR), Av. Pellegrini 250, 2000 - Rosario, Argentina In this work we study theoretically the structures in the triply-differential cross section for electron impact ionization of excited hydrogenic atoms at intermediate and high impact energies. A new analytical and numerical technique is introduced to calculate the cross sections.