Variational study of atomic hydrogen ionization by electrons impact

Triple differential cross section results of the electron impact ionization of hydrogen atom are performed in the so-called Schwinger-Born approximation of variational principle of Schwinger. In the theoretical calculations the first Born term was calculated analytically, and the second Born term was determined in the closure approximation using semi-analytical calculations. The theoretical results were corrected by the so-called Gamow factor in order to include post-collision effects, then compared with experiments performed with an incident electron energy of E_i = 250 eV and with those of other models. Better agreement was found between our results and experimental data even for high values of the ejected electrons energy (50 eV). (paper)