Evidence of Initial-state Two-Center Effects for (e, 2e) Reactions

Coincidence, or (e, 2e), measurements of electron-impact ionization of atoms have established that the largest values of triply differential cross sections are obtained in collisions involving small momentum transfer to the target. Absolute measurements for these reactions are now available for hydrogen at 54.4-eV impact energy, and relative data have recently been reported at 27.2 eV. Previous theoretical works have concentrated on employing asymptotically correct two-center wave functions for the final state, leaving the initial state described by the Born approximation. Here we report results for which asymptotically correct two-center wave functions are used for both the initial and final states of the scattering system. Comparison of these results with experiment reveals that two-center effects (projectile-target correlations) are also important in the initial state