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L-shell ionization of Cd, Sb, Te, Ba, La, Eu, Tb and Yb by ^16O ions in the energy range from 0.19 to 0.75 MeV u^-1

Lalpha_1, 2, Lbeta_1, 3, 4, Lbeta_2, 15, Lgama_1(5) and Lgama_2, 3(4, 4') X-ray production cross-section have been measured on selected medium-Z elements using ^16O ions with energies from 0.19 to 0.75 MeV u^-1. Calculated L-subshell ionization cross-sections were compared with the predictions of the direct ionization theories. The ECPSSR theory, the semiclassical approximation (SCA) in the united atom limit (SCA-UA) and SCA coupled-channel calculations (SCA-CC) involving a few lowest lying states. For the ECPSSR theory, large discrepancies were found for all three subshells. Better overall agreement between the experiment and theory was found for the SCA-UA theory. SCA-CC calculations improved the agreement between experiment and theory for the L_2-subshell in the very adiabatic region. By measuring the Lalpha X-ray production cross section was estimated to be less than 20%. The degree of multiple ionization of outer shells caused by heavy ion bombardment was estimated from the X-ray line energy shifts and by comparing the X-ray intensity ratios for heavy ions and protons.

oxygen ions; L shell ionization; L-subshell ionization; cross section; Born approximation; semiclassical approximation; united atomn; coupled channel; electron capture; multiple ionization

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