Fine Structure Analysis in EELS: Quantum Mechanics and Applications

This lecture focuses on fine structure analysis in electron energy loss spectroscopy (EELS), emphasizing the quantum mechanics underlying inelastic scattering. The instructor begins by explaining the core principles of coalesci spectroscopy, detailing how fast electrons interact with core-level electrons in atoms, leading to energy loss. The discussion includes the double differential scattering cross-section, which is crucial for understanding transition probabilities during electron interactions. The instructor elaborates on the significance of matrix elements and the Coulomb potential in these interactions. The lecture also covers the challenges of quantifying chemical compositions in materials using EELS, highlighting the importance of understanding the final state of electrons above the Fermi level. The instructor presents examples of fine structure analysis, particularly in strained materials, and discusses the role of density functional theory (DFT) in modeling these systems. The session concludes with a discussion on angular resolved EELS, demonstrating how specimen orientation affects fine structure observations, particularly in anisotropic materials like graphite and boron nitride.