We have observed surface-molecule electron transfer from the semiconductor diamond (111) surface to the iodine molecule, following hyperthermal molecular-beam scattering. The negative-ion mass spectrum was dominated by undissociated molecular ions. No positive ions were observed. The threshold kinetic energy was ≅ 3 eV and an absolute yield of ≅ 1% was measured at 10-eV incident kinetic energy. The surface temperature effect on the yield was small. The ions' energy distribution was broad and the angular distribution was shifted towards the surface.

• Received 12 September 1988

DOI:https://doi.org/10.1103/PhysRevLett.61.2961