Direct methods and applications to electron crystallography

A study was conducted to describe the basics of the direct methods and their applications to electron crystallography. Theoretical considerations were discussed along with descriptions of some practical aspects and applications. The direct methods assumed that the crystal structure was potentially derived from the experimental knowledge of the moduli. It was demonstrated that there were combinations of phases that were origin-independent as they depended only on the crystal structure and had the potential to be estimated by means of the diffraction moduli. It was observed that electron diffraction was receiving increasing attention as a means of obtaining structural information when crystal structure solution was not achievable by X-ray techniques due to advancements in methods and instrumentation. Any perturbation causing observed magnitudes to deviate from the moduli of the Fourier transform of the potential field weakened the efficiency of the methods, as they relied on diffraction magnitudes.