Dissociation of polyatomic ions at surfaces: the influence of mechanical and electronic energy transfer
The dissociative scattering of CF3+ions from a clean Ag(111) surface was explored in the energy range 100-600 eV. Both negative (CF3–, CF2–, and F–) and positive ions (CF+ and C+) were formed. The complete dissociation of the CF3+ molecular ions into C+ fragments was found to be feasible at low (normal) incoming energies. We conclude that the breaking of three C-F bonds is due to concerted electronic and mechanical energy transfer. The azimuthal orientation of the crystal has a large influence on the degree of dissociation, which indicates the importance of direct momentum transfer.