Quasi-elastic electron scattering from atoms and molecules

Over the past four years we have measured quasi-elastic electron scattering spectra from molecules and atoms at large momentum transfer (100° angle, 2.25keV incident energy, ∼20a.u.). The peak positions agree completely with those predicted by classical conservation of momentum and energy, assuming the electron scatters from each atom independently. However the peak intensities do not agree with expectations, particularly for light elements. …