IONIZATION EXCITATION OF HELIUM-LIKE IONS BY HIGH-ENERGY ELECTRONS
The differential and total cross sections for ionization of helium-like ions with a simultaneous excitation of the residual ion to ns states by electron impact are evaluated. Nonrelativistic perturbation theory in the inter-electron interaction using the Coulomb functions as the zeroth approximation is employed as a method of calculation. The formulas obtained exhibit the universal behavior. The range of their applicability is restricted by moderate values of the nuclear charge number Z of target and high energies of incident electrons. A comparison between the total cross sections for helium atom calculated within the framework of different theoretical methods is given.