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  2. X-ray crystallography - Wikipedia

    en.wikipedia.org/wiki/X-ray_crystallography

    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.

  3. R-factor (crystallography) - Wikipedia

    en.wikipedia.org/wiki/R-factor_(crystallography)

    The minimum possible value is zero, indicating perfect agreement between experimental observations and the structure factors predicted from the model. 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.

  4. X-ray crystal truncation rod - Wikipedia

    en.wikipedia.org/wiki/X-ray_crystal_truncation_rod

    The maximum diffracted intensity is roughly proportional to the square of the atomic number, . [3] Anode X-ray sources have been successfully used to study gold ( Z = 79 {\displaystyle Z=79} ) for example.

  5. Rietveld refinement - Wikipedia

    en.wikipedia.org/wiki/Rietveld_refinement

    Rietveld refinement is a technique described by Hugo Rietveld for use in the characterisation of crystalline materials. The neutron and X-ray diffraction of powder samples results in a pattern characterised by reflections (peaks in intensity) at certain positions. The height, width and position of these reflections can be used to determine many ...

  6. Scherrer equation - Wikipedia

    en.wikipedia.org/wiki/Scherrer_Equation

    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.

  7. Structure factor - Wikipedia

    en.wikipedia.org/wiki/Structure_factor

    This set of values forms a lattice, called the reciprocal lattice, which is the Fourier transform of the real-space crystal lattice. In principle the scattering factor () can be used to determine the scattering from a perfect

  8. X-ray scattering techniques - Wikipedia

    en.wikipedia.org/wiki/X-ray_scattering_techniques

    Note that X-ray diffraction is sometimes considered a sub-set of X-ray scattering, where the scattering is elastic and the scattering object is crystalline, so that the resulting pattern contains sharp spots analyzed by X-ray crystallography (as in the Figure).

  9. Phase problem - Wikipedia

    en.wikipedia.org/wiki/Phase_problem

    A number of initial phases are tested and selected by this method. The other is the Patterson method, which directly determines the positions of heavy atoms. The Patterson function gives a large value in a position which corresponds to interatomic vectors. This method can be applied only when the crystal contains heavy atoms or when a ...