Elastic Small-Angle Electron Scattering by He, Ne, and Ar at 35 keV

Abstract
New experimental data are presented for the scattering of 35-keV electrons by He, Ne, and Ar in the limit of vanishing momentum transfer. Previous data of Geiger and Morón-León show a strong forward peak with structures similar to a Fraunhofer diffraction pattern (shadow scattering) for elastic scattering of 15-25-keV electrons. No recent theory can explain this effect; therefore we repeated the experiment. The new data agree well with partial-wave calculations utilizing configuration interaction and Hartree-Fock potentials. The results are compared with the previous unexpected findings.