Search results
Results from the WOW.Com Content Network
The Scherrer equation, in X-ray diffraction and crystallography, is a formula that relates the size of sub-micrometre crystallites in a solid to the broadening of a peak in a diffraction pattern. It is often referred to, incorrectly, as a formula for particle size measurement or analysis.
An X-ray diffraction pattern of a crystallized enzyme. The pattern of spots (reflections) and the relative strength of each spot (intensities) can be used to determine the structure of the enzyme. The relative intensities of the reflections provides information to determine the arrangement of molecules within the crystal in atomic detail.
The resulting map of the directions of the X-rays far from the sample is called a diffraction pattern. It is different from X-ray crystallography which exploits X-ray diffraction to determine the arrangement of atoms in materials, and also has other components such as ways to map from experimental diffraction measurements to the positions of atoms.
The first X-ray diffraction experiment was conducted in 1912 by Max von Laue, [7] while electron diffraction was first realized in 1927 in the Davisson–Germer experiment [8] and parallel work by George Paget Thomson and Alexander Reid. [9] These developed into the two main branches of crystallography, X-ray crystallography and electron ...
The most common powder X-ray diffraction (XRD) refinement technique used today is based on the method proposed in the 1960s by Hugo Rietveld. [2] The Rietveld method fits a calculated profile (including all structural and instrumental parameters) to experimental data.
There is no theoretical maximum, but in practice, values are considerably less than one even for poor models, provided the model includes a suitable scale factor. Random experimental errors in the data contribute to R {\displaystyle R} even for a perfect model, and these have more leverage when the data are weak or few, such as for a low ...
X-ray diffraction (XRD) X-ray fluorescence spectroscopy (XRF) X-ray microscopy (XRM) See also. Analytical chemistry; List of materials analysis methods
XRD may refer to: X-ray diffraction , used to study the structure, composition, and physical properties of materials Extensible Resource Descriptor , an XML format for discovery of metadata about a web resource