Negative ion formation in the scattering of CF+3 from graphite

The scattering of CF⁺₃ from highly oriented pyrolytic graphite results in the formation of CF^-₃. Comparison is made with CF⁺₃ scattering from a metal and from an insulator surface, which do not yield negative molecular ions. The outcome of the charge transfer processes that occur as CF⁺₃ approaches a surface is critically dependent on the electronic properties of that surface. The ability to produce a stable negative ion close to a surface may be an important factor in the etching efficiency of the CF⁺₃ molecule.