Projectile 1s→2p excitation due to electron-electron interaction in collisions of O/sup 5+/ and F/sup 6+/ ions with H2 and He targets

Evidence is presented of an excitation process in ion-atom collisions analogous to electron-impact excitation in free-electron-ion collisions. The production of (1s2s2p)4P projectile states excited in collisions of (1s22s) O/sup 5+/ and F/sup 6+/ with He and H2 targets was found to increase with projectile energy above /similar to/0.75 MeV/u, in agreement with an impulse-approximation treatment of 1s→2p electron-impact excitation of ions in collisions with ''quasifree'' target electrons. Such ion-atom excitations could provide presently unavailable information about inner-shell electron-impact excitation