Theoretical ionization cross-sections in the K-shell - Hydrogenic model and beyond

The K-shell ionization cross-sections are studied in a semiclassical model that takes into account the projectile kinematics in the field of nucleus and atomic electrons, and considers the time evolution of the wave functions within a simplified coupled-channel approach. The wave functions are Dirac hydrogenic, though a correction of using the Hartree-Fock field is proposed. The calculation is non-hydrogenic in the estimate of the continuum-continuum interaction. A comparison with the experiment was performed for the elements that exhibit a large number of measured points, and for the reference data. With respect to the united atom semiclassical model, the present calculation provides a more realistic description of the binding effect and agrees better with the experimental data in lighter atoms. As for the ECPSSR theory, general validity of this method in light and medium atoms was confirmed, though the present model, on account of precise projectile kinematics, reproduces better the adiabatic region of heavy elements. (C) 2002 Elsevier Science B.V. All rights reserved.