Ion scattering:a spectroscopic tool for study of the outermost atomic layer of a solid surface

Noble gas ions which are back-scattered from crystal surface lose a specific amount of energy for surface atoms of a specific mass. The chemical reaction of a silicon (III) crystal surface with bromine has been followed using He+ and Ne+ ion scattering. It is shown that this technique can be used to study the first atomic layer of a surface selectively. Methods using ion scattering to study vibrations of surface atoms are also indicated.