Elastic Scattering: Interactions of Electrons with Matter

This lecture provides an in-depth examination of elastic scattering, focusing on the interactions of fast electrons with matter. The instructor begins by introducing the concept of elastic scattering, emphasizing that the energy and wavelength of the fast electron remain unchanged during the scattering process. The discussion progresses to the Schrödinger equation and the treatment of electron waves in a uniform potential field. The instructor explains the derivation of the refractive index for electrons in a medium and how the potential affects the speed and wavelength of the electron wave. The lecture also covers the scattering from atomic potentials, leading to the formulation of the Mott formula, which describes the scattering amplitude in relation to the atomic structure. The instructor illustrates the scattering geometry and the significance of the scattering angle in determining the intensity of the scattered wave. The session concludes with a summary of the key concepts, including the effective refractive index and the implications of scattering by individual atoms, setting the stage for future discussions on lattice scattering.