Excitation into the molecular ionization continuum in potassium atom alkyl halide collisions

Relative cross sections for the production of positive molecular and molecular fragment ions by collision with fast K atoms are reported. In the collision energy range between 100 and 1000eV the observed fragmentation patterns for CF 3 I and CH 3 I show that excitation is dominantly to electronically excited states of the parent ion. The mechanism for this excitation is discussed and a model involving autoionization from a state with a low lying vacancy proposed.