5. Diffraction Table of contents 5.1 Fundamentals 5.2 Characteristics of diffraction patterns 5.3 Structure factors 5.4 Structure solutions 5.1 Fundamentals Questions & answers 💍 What is the relation between the Laue diffraction condition and the Bragg’s equation? 💍 Given a crystal with unit cell volume V and a wavelength λ for the incident beam, how many different intensities can be collected in a diffraction experiment? 💍 What is the Ewald sphere and how to use it? 💍 In an X-ray diffraction experiment, is the wavelength of the incident and the diffracted beam the same? 💎 How do I identify crystal patterns? 💎 How is the Laue method used in studying crystals? 💎 What difference would twinning make to powder diffraction pattern? 💎 What are modern x-ray films made of (CR)? 💎 How do you explain the differences of XRD peak intensities the same material? 💎 What are k-alpha and k-beta peaks in the X-ray spectrum? Why do X-rays have a "continuous" spectrum? 💎 What methodology and apparatus are used to analyze the crystal structure? 💎 Is crystallography able to detect the presence of atoms other than carbon and hydrogen in a crystal? I mean atoms like fluorine, magnesium, etc. 💎 How does powder crystallography work? How do we construct the crystal structure of the particles from the diffraction patterns observed? 💎 What is the difference between X-ray crystallography and x-ray diffraction? 💎 Is it okay to delete a substrate peak from an XRD pattern? If possible, which software can be used? 💎 Why do crystals diffract X-rays? 💎 In X-ray diffraction pattern, the position of peaks depend on what factor, the linear constant of the planes or the size and shape of crystal? 5.2 Characteristics of diffraction patterns Questions & answers 💎 Why do we use (100) or other ways of showing for silicon crystals? Don't they all have the same spatial distribution? 💎 What is an aperiodic crystal? 5.3 Structure factors Questions & answers 💎 How can you calculate the structure factor for a 75% Ni 25% Fe DISORDERED system? 💎 How many types of structure factors are there in crystallography? 💎 What is the atomic structure factor in crystallography? 5.4 Structure solutions Questions & answers 💎 The biggest problem in crystallography is solving the phases. Why is this not solved using principles that holography uses (the reference wave) for obtaining the phases? Are current x-ray sources not coherent enough, or is there another problem? 💍 How can you obtain the crystal structure of a crystalline compound from the experimental diffraction data? 💍 What is the charge flipping algorithm? 💎 What is the name of the effect, which helps in determining the structure of ionic solid? 💎 How can X-ray diffraction determine the crystalline structure of powders with randomly oriented crystals? 💎 How do you calculate HKL values from XRD?