Low energy de-excitation and neutralization processes near surfaces

The electronic transitions near solid surfaces that deexcite and neutralize atomic particles carrying potential energy, such as Auger neutralization and the two-stage process of resonance neutralization followed by Auger de-excitation, are discussed. Experimental evidence for atomic energy level variation near surfaces is reviewed and the critical distance separating regions outside the surface where different processes occur is defined. Further evidence for the general validity of the theoretical picture is that provided in the investigation of the processes occurring for the metastably excited He+(2s) ion