Projectile charge-state dependence ofK-shell ionization by silicon ions: A comparison of Coulomb ionization theories for direct ionization and electron capture with x-ray production data

X-ray-production cross sections measured in K-shell ionization of ₂₁Sc, ₂₂Ti, ₂₉Cu, and ₃₂Ge by 52-MeV ₁₄²⁸Si+q projectiles with q=7 to 14 are reported, which demonstrate, through their charge-state dependence, the validity of a recently developed electron-capture theory with a reduced binding effect. Furthermore, the data provide evidence for the applicability of the perturbed stationary-state theory of direct ionization for values of 0.44≤Z₁Z₂≤0.67.