Mean free path of inelastic electron scattering in elemental solids and oxides using transmission electron microscopy: Atomic number dependent oscillatory behavior

Mean free path of inelastic electron scattering lambda has been measured with a 200 keV transmission electron microscope for the majority of stable elemental solids and their oxides. An oscillating behavior vs atomic number Z has been revealed, such that within one row of the Periodic Table, the minimum (maximum) of lambda is observed for elements with completed (empty) outer d shells. A significantly weaker lambda(Z) dependence is observed for the oxides. The lambda(Z) variation is ascribed to the three major factors: atomic density, number of free electrons per atom, and contribution of atomic core-loss transitions.