MOLECULAR EFFECTS IN MEASURED SPUTTERING YIELDS ON GOLD AT NEAR-THRESHOLD ENERGIES

We report on first measurements of sputtering yields of NO+ on polycry stalline gold targets at near threshold energies. The results are comp ared to N+ and O+ sputtering yields as well as N-2(+) and O-2(+) sputt ering yields at the same velocities. When sputtering yields of NO+, N and O+ (per incident atom) are compared, a pronounced enhancement is observed for NO+ below about 190 eV per atom. The onset of the effect is measured to lie between that observed for O-2(+) (75 eV) and N-2(+) (350 eV). We discuss this correlation in the context of the binding e nergies and vibrational periods of the incident molecules.