Charge dependence of total K-shell vacancy-production cross sections in argon by the impact of heavy ions

The charge dependence of K-shell-electron vacancy production in argon by heavy-ion impact is found by adding charge-exchange and ionization cross sections computed in the binary-encounter approximation. The dependence of these cross sections on the nuclear charge, for fully stripped ions (z=6,7,8,and 9), is in agreement with recent experimental results at 1.88 MeV/amu, where large deviations (>100%) from a z² dependence were observed. The dependence of atomic charge q for $F^{+q}$ at 1.88 MeV/amu (q=9,7,8,6,and 5) is in reasonable agreement with experiment.