Ionisation of atomic hydrogen at intermediate momentum transfer

Relative differential cross sections for the asymmetric coplanar (e,2e) reaction have been measured in three energy-sharing regions, for two of which the ionisation peak is about 1 a.u. off the Bethe ridge. Momentum transfer is intermediate between large (binary) and small (dipole) values, where the distorted-wave impulse and second Born approximations respectively give a good account of the experimental data. In addition to these approximations the distorted-wave Born approximation is calculated. It is somewhat superior to the distorted-wave impulse approximation and very much better than the second Born approximation