The non-relativistic transition T-matrix element for electron impact ionization of H-like has been calculated with starting from the formulation of Brauner,Briggs and Klar.The final state wavefunction involving three appropriate confluent hypergeometric functions considers all three two-body interactions on an equal footing and satisfies the proper Coulomb boundary conditions.The long range Coulomb interaction occurring in the initial channel has been taken into account properly.The T-matrix element,including four confluent hypergeometric functions,has been reduced to a three-dimensional integral in real space.The results are of use in a wide class of scattering problems.

A general method to calculate the triple differential cross sections(TDCS) for electron impact ionization of hydrogen atom,hydrogenicion He⁺, helium atom and helium-like ion Li⁺is given by generalizing the theoretical framework developed by Brauner et al. The present TDCS results of H, He⁺, He and Li⁺are compared with those of other theoretical models and/or experiment, and good agreements have been found.