ADIABATIC L-SHELL IONIZATION OF HG AND TL BY PROTON AND HE-4 ION IMPACT

L-shell x-ray production cross sections by proton and He-4 ion impact on Hg and T1 (of great importance from the biological point of view, o wing to their moderate toxicity properties) have been measured in the energy ranges 0.3 less than or equal to E-p less than or equal to 2.6 MeV and 0.7 less than or equal to E4He less than or equal to 1.8 MeV, respectively. L-subshell ionization cross sections have been extracted and arranged, together with the few existing data from other laborato ries, in an analysis aimed at testing the performance of various theor etical approximations in the description of the ionization process. Th e disagreement observed at low values of the reduced velocity paramete r xi(L)(R) between the data and the predictions of the ECPSSR model is reduced significantly by using a united-atom approximation in the tre atment of the binding correction, suggested by our group (ECPSSR-UA). The remaining discrepancies, mostly for the L-1-subshell, are strongly reduced by replacing the screened hydrogen-like wavefunctions with th e more realistic Dirac-Hartree-Slater ones. In the case of He-4 ions, especially for the L-2-subshell, a more refined Coulomb deflection cor rection and/or more sophisticated coupled-channels calculations are al so needed.