Determining atomic arrangement using electron diffraction In materials characterization, can the arrangement of atoms in a solid be inferred by analyzing its electron diffraction pattern (e.g., in TEM or LEED techniques)?

Introduction / Context:
Electron diffraction exploits the wave nature of electrons to probe crystal structures. Techniques such as transmission electron microscopy (TEM) selected-area electron diffraction (SAED) and low-energy electron diffraction (LEED) reveal reciprocal-space information that maps to real-space periodicity and symmetry, enabling identification of lattice parameters, orientations, and defects.

Given Data / Assumptions:

• Electrons have de Broglie wavelengths at typical accelerating voltages comparable to interatomic spacings.
• Kinematic or dynamic diffraction conditions apply depending on thickness and energy.
• Crystalline or polycrystalline specimens are considered; amorphous materials yield diffuse halos.

Concept / Approach:

Bragg’s law and reciprocal lattice concepts explain electron diffraction patterns. Spot or ring patterns correspond to allowed reflections from sets of lattice planes. By indexing the pattern (measuring spacings and angles), one can deduce crystal structure, lattice constants, grain orientation, and sometimes identify phases. In LEED, surface periodicities are probed due to the shallow penetration of low-energy electrons.

Step-by-Step Reasoning:

Verification / Alternative check:

Practical materials labs routinely use SAED or nano-beam diffraction to confirm phases and orientations after synthesis or heat treatment; crystallographers also use X-ray diffraction similarly, but electrons provide stronger scattering and surface sensitivity.

Why Other Options Are Wrong:

• “False”: contradicts well-established electron diffraction techniques.
• “Only for amorphous” or “only for liquids”: reversed; crystals give discrete patterns; amorphous gives diffuse rings; liquids rarely measured this way for structure.
• “Electrons do not diffract”: incorrect, electrons exhibit wave–particle duality.

Common Pitfalls:

Assuming electron diffraction works identically to X-ray diffraction; electron–matter interactions are stronger, leading to multiple scattering (dynamic effects) that must be considered in analysis.

Final Answer:

True