In physics, the phase problem is the problem of loss of information concerning the phase that can occur when making a physical measurement. The name comes from the field of X-ray crystallography, where the phase problem has to be solved for the determination of a structure from diffraction data. The phase … See more Light detectors, such as photographic plates or CCDs, measure only the intensity of the light that hits them. This measurement is incomplete (even when neglecting other degrees of freedom such as See more • Coherent diffraction imaging • Ptychography • Phase retrieval See more There are several ways to retrieve the lost phases. The phase problem must be solved in x-ray crystallography, neutron crystallography, and electron crystallography See more Refining initial phases In many cases, an initial set of phases are determined, and the electron density map for the diffraction … See more • An example of phase bias • An appropriate use of 'molecular replacement' See more WebThis labor-intensive approach to the phase problem, referred to as ‘multiple isomorphous replacement (MIR)’ or more simply the ‘heavy-atom method’, is the oldest and technically most challenging way to solve the X-ray crystal structure of a biological macromolecule.
The Direct Methods of X-ray Crystallography Science
WebApr 1, 2024 · One of the first applications of these models is in solving the `phase problem' encountered in X-ray crystallography in calculating electron-density maps from diffraction data. Indeed, the... WebNov 1, 1991 · Thus, a 'phase' phi H, unobtainable from the diffraction experiment, must be assigned to each mod E H mod , and the problem of determining the phases when only the magnitudes mod E H mod are known is called 'the phase problem'. Owing to the known atomicity of crystal structures and the redundancy of observed magnitudes mod E H mod … florist in lake wales fl
Direct methods (crystallography) - Wikipedia
WebMay 28, 2003 · X-ray crystallography can provide detailed information about the structure of biological molecules if the ‘phase problem’ can be solved for the molecule under study. The phase problem... WebAlthough X-ray crystallography remains the premier technology to ascertain the structure of proteins, there remain two fundamental problems with this technique. First, the proteins are confined in the crystal lattice so that large-scale … WebCrystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics ( condensed matter physics ). The word "crystallography" is derived from the Greek word κρύσταλλος ( krystallos) "clear ice, rock ... florist in lakeway tx