Transmission and reflection of low-energy electrons at the surface barrier of a metal

LEED calculations are presented which indicate that the emergence of a non-specular beam is accompanied with a surface resonance fine structure in the intensity of the specular beam. It is shown that the fringes of the fine structure are arranged in a Rydberg series having the constant 1/16 Rydbergs and terminating at the energy of emergence. The resonances are caused by reflections of electrons between the image potential before the metal surface on one side and the bulk of the metal on the other. The resolving power required for recording the fine structure is discussed and the calculated fine structure is compared with three electron scattering experiments.