FINE-STRUCTURE EFFECT IN ELECTRON-IMPACT IONIZATION

Spin resolved (e,2e) experiments provide an extremely sensitive test o f theories of electron impact ionization and many-body Coulomb effects . We present here results for (e,2e) collisions with xenon which show the First experimental evidence of the fine structure effect in electr on impact ionization, analogous to the well known effect in electron i mpact excitation of atoms by polarized electrons. Comparison with dist orted-wave Born-approximation calculations shows the sensitivity of th e results to details of the target atom wave functions as well as the treatment of relativistic effects.