Non-dipole effects in (e, 2e) and photoelectron experiments:: a comparison

Photoelectron and (e, 2e) experiments are compared under limiting conditions. The results of an (e, 2e) experiment in the helium au-toionizing region are presented. Spectra taken for ejected electron directions 180degrees apart are analyzed using a new technique involving fundamental magnitudes and phases. It is shown that although all quantities may not be deduced from the experimental data, reliable values may be obtained for the net magnitude and phase of the summed non-resonant even parity amplitude relative to those of the resonant dipole amplitude. (C) 2004 Elsevier B.V. All rights reserved.