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In condensed matter physics and crystallography, the static structure factor (or structure factor for short) is a mathematical description of how a material scatters incident radiation. The structure factor is a critical tool in the interpretation of scattering patterns ( interference patterns ) obtained in X-ray , electron and neutron ...
The pair correlation function is related via Fourier transform to the static structure factor, which can be determined experimentally using X-ray diffraction or neutron diffraction. The OZ equation relates the pair correlation function to the direct correlation function. The direct correlation function is only used in connection with the OZ ...
In condensed matter physics, the dynamic structure factor (or dynamical structure factor) is a mathematical function that contains information about inter-particle correlations and their time evolution. It is a generalization of the structure factor that considers correlations in both space and time.
The structure factor is a complex number containing information relating to both the amplitude and phase of a wave. In order to obtain an interpretable electron density map , both amplitude and phase must be known (an electron density map allows a crystallographer to build a starting model of the molecule).
Static structure factor of the hard-spheres liquid in Percus–Yevick approximation at three different packing ratios. For hard spheres, the potential u(r) is either zero or infinite, and therefore the Boltzmann factor / is either one or zero, regardless of temperature T. Therefore structure of a hard-spheres fluid is temperature independent.
One can determine () indirectly (via its relation with the structure factor ()) using neutron scattering or x-ray scattering data. The technique can be used at very short length scales (down to the atomic level [ 10 ] ) but involves significant space and time averaging (over the sample size and the acquisition time, respectively).
Atoms with low B-factors belong to a part of the structure that is well ordered. Atoms with large B-factors generally belong to part of the structure that is very flexible. Each ATOM record (PDB file format) of a crystal structure deposited with the Protein Data Bank contains a B-factor for that atom.
The process is then repeated with the new structure factor estimate. At this point, the unit cell, background, peak widths, peak shape, and resolution function are refined, and the parameters are improved. The structure factor is then reset to the new structure factor value, and the process begins again.