An accurate calculation for impact ionization cross sections of atoms by electron

A theoretical method called multiple-scattering expansion was proposed and developed by author in the previous works. This method has a few advantages, such as, high accuracy, simplicity for calculations and wide valid region. This method has been applied to calculations for the impact ionization cross sections of H-atoms, and the results are in agreement with the experimental data very well. A detailed description for practical calculations based on this method is given