Ionization, charge exchange, and excitation in F + Ar and F + Kr collisions

We have measured projectile and target x-ray cross sections for F + Ar and F + Kr collisions using fluorine beams of charge states 7+, 8+, and 9+ with energies from 20 to 76 MeV. Pronounced enhancements for the Ar K and Kr L vacancy cross sections using F9+ ions compared to those for the 7+ projectile can be explained by charge exchange as described by an empirically scaled Brinkman-Kramers theory. The Ar L, Kr K, and Kr M cross sections are found to exhibit features expected for Coulomb ionization. The projectile K x- ray production for the 9+ ion is accounted for by charge exchange processes. Predictions of the first Born approximation for direct single-step excitation to bound states by the target nucleus overestimate the observed cross sections for F7+ and F8+.