Effective Sommerfeld parameters in the three-body Coulomb continuum problem

The three-body Coulomb continuum wave function as a product of three two-body Coulomb wave functions is modified by the introduction of an Ansatz for effective Sommerfeld parameters corresponding to the modification of a particular two-body Coulomb interaction by the presence of the third particle. The triple-differential cross sections for electron-impact ionization of atomic hydrogen at incident energies of 54.4 and 150 eV in asymmetric geometry are calculated. We generally find that this approach gives good agreement with experiment, though some small quantitative discrepancies remain.