  The K x-ray spectra of different targets (Cu, Zn, and Ge) induced by 3 to 5
MeV/u Si projectile ions have been measured to determine the K-shell ionization
cross-section. A significant difference is observed between the measurements
and theoretical estimates, with the latter being about 50% below the
experimental results. This underestimation} is attributed to the
charge-exchange from target K-shell to projectile K- and L-shells. Such
observation can only be possible if the projectile ions attain up to H- and
He-like charge states. Corresponding projectile charge state fractions have
been evaluated from the Lorentzian charge state distribution, where mean charge
state is taken from the Fermi gas model [Phys. Rev. Lett. 30, 358 (1973)] and
width from the Novikov and Teplova approach [Phys. Lett. A378, 1286-1289
(2014)]. The sum of the direct ionization cross-section and K-K + K-L capture
cross-sections gives a good agreement with the measured cross-sections.
Furthermore, we have validated this methodology with available data for Si-ion
on Ti target. Such results may be useful in many solid target based
applications.
