{ "id": "epsgs7yfwc", "slug": "anomalous-x-ray-scattering", "title": "Anomalous X-ray scattering", "updated": "2026-10-15", "topic_path": [ { "id": "physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical" }, { "id": "physical.physics", "label": "Physics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.physics" }, { "id": "physical.physics.matter-and-radiation", "label": "Matter and radiation physics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.physics.matter-and-radiation" }, { "id": "physical.physics.matter-and-radiation.condensed-matter", "label": "Condensed matter physics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.physics.matter-and-radiation.condensed-matter" }, { "id": "physical.physics.matter-and-radiation.condensed-matter.cm-structures", "label": "Crystal and structural condensed matter", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.physics.matter-and-radiation.condensed-matter.cm-structures" } ], "geo": [ { "id": "geo.nongeo.t1800.physical.physics.matter-and-radiation", "label": "Non-geographic · 1800 to 1945: Matter and radiation physics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.physics.matter-and-radiation", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1800", "label": "Non-geographic · 1800 to 1945", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800" }, { "id": "geo.nongeo.t1800.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical" }, { "id": "geo.nongeo.t1800.physical.physics", "label": "Physics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.physics" }, { "id": "geo.nongeo.t1800.physical.physics.matter-and-radiation", "label": "Matter and radiation physics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.physics.matter-and-radiation" } ] }, { "id": "geo.nongeo.t1946.physical.physics.matter-and-radiation.condensed-matter.cm-structures", "label": "Non-geographic · 1946 to 2000: Crystal and structural condensed matter", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.physics.matter-and-radiation.condensed-matter.cm-structures", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1946", "label": "Non-geographic · 1946 to 2000", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946" }, { "id": "geo.nongeo.t1946.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical" }, { "id": "geo.nongeo.t1946.physical.physics", "label": "Physics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.physics" }, { "id": "geo.nongeo.t1946.physical.physics.matter-and-radiation", "label": "Matter and radiation physics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.physics.matter-and-radiation" }, { "id": "geo.nongeo.t1946.physical.physics.matter-and-radiation.condensed-matter", "label": "Condensed matter physics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.physics.matter-and-radiation.condensed-matter" }, { "id": "geo.nongeo.t1946.physical.physics.matter-and-radiation.condensed-matter.cm-structures", "label": "Crystal and structural condensed matter", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.physics.matter-and-radiation.condensed-matter.cm-structures" } ] } ], "excerpt": "Anomalous X-ray scattering is a diffraction technique that tunes X-ray energy near an element's absorption edge, making its scattering factor complex for element-specific structure and phase information.", "snippet": "Anomalous X-ray scattering is a diffraction technique that tunes X-ray energy near an element's absorption edge, making its scattering factor complex for element-specific structure and phase information.", "node": "physical.physics.matter-and-radiation.condensed-matter.cm-structures", "markdown": "# Anomalous X-ray scattering\n\nAnomalous X-ray scattering is a diffraction technique that tunes the X-ray energy close to an absorption edge (X-ray energy matching an inner-shell electron's binding energy) of a chosen element, making its scattering factor complex to yield element-specific structure and phase information that ordinary diffraction cannot provide. The effect underlies phasing methods such as MAD and SAD, absolute-structure determination, and resonant diffraction studies of materials.[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) • [2](https://doi.org/10.1126/science.1925561) In macromolecular crystallography, single-wavelength anomalous diffraction now dominates de novo structure determination, accounting for over 70% of de novo structures deposited to the [Protein Data Bank](https://www.edgepedia.org/protein-data-bank) in 2013.[3](https://www.nature.com/articles/ncomms13388)\n\n| Key fact | Value |\n|---|---|\n| Scattering factor near an edge | \\( f = f^{\\circ} + f' + i f'' \\), with energy-dependent corrections \\( f' \\) and \\( f'' \\)[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) |\n| Dispersion corrections | \\( f''(E) = K \\cdot \\mu(E) \\cdot E \\) (proportional to absorption); \\( f' \\) follows from \\( f'' \\) by the Kramers–Kronig relation[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) • [4](https://www.pnas.org/doi/10.1073/pnas.191003998) |\n| Typical Bijvoet signals | <1% for S-SAD at 8 keV; ~4% for SeMet-SAD at the Se K edge[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/) |\n| Accessible edges | The ~3.5–35 keV diffraction range covers K and/or L edges for all elements with Z ≥ 20 (Ca upward); H, C, N, and O scatter anomalously negligibly there[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) |\n| Energy resolution needed | The separation between the \\( f'' \\) peak and the \\( f' \\) inflection is often only a few eV out of 10,000 eV[6](https://mol-xray.princeton.edu/xray0/Guides/MAD_example1.html) |\n| First absolute configuration | Sodium rubidium (+)-tartrate tetrahydrate, Bijvoet, Peerdeman, and van Bommel, 1951[7](https://doi.org/10.1038/168271a0) |\n\n## How it works\n\nOrdinary [X-ray scattering](https://www.edgepedia.org/x-ray-scattering) by an atom is described by a real factor \\( f^{\\circ} \\) that depends on the number of electrons and on scattering angle. Near an absorption edge, where the photon energy matches the binding energy of an inner-shell electron, resonance between the X-ray waves and electronic transitions from bound atomic orbitals makes the true atomic scattering factor complex: \\( f = f^{\\circ} + f' + i f'' \\).[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) • [2](https://doi.org/10.1126/science.1925561) Because the anomalous term derives from core electrons, it is essentially independent of scattering angle, but unlike normal scattering it is a strong function of wavelength.[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970)\n\nThe two corrections behave differently as energy scans through an edge: \\( f'' \\) jumps rapidly to a maximum while \\( f' \\) dips and then rises again as the energy goes from below to above the edge.[8](http://www.crystal.chem.uu.nl/~schreurs/reprints/GD3231.pdf) \\( f'' \\) is proportional to the X-ray absorption spectrum, \\( f''(E) = K \\cdot \\mu(E) \\cdot E \\), and \\( f' \\) is related to \\( f'' \\) by the Kramers–Kronig dispersion integral, so both can be obtained from absorption measurements.[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) • [4](https://www.pnas.org/doi/10.1073/pnas.191003998) The \\( f'' \\) term breaks Friedel's law: for noncentrosymmetric structures the intensities of Friedel pairs, \\( hkl \\) and \\(\\bar h\\bar k\\bar l\\), are no longer equal, and choosing a wavelength close to an absorption edge produces these Bijvoet differences.[8](http://www.crystal.chem.uu.nl/~schreurs/reprints/GD3231.pdf)\n\n## How it is done\n\nThe experimenter selects an absorption edge accessible at the beamline, then calibrates the energy. For selenium labeling, a two-stage fluorescence scan is standard: a Se foil EXAFS scan calibrates the energy to the Se K edge at 12.67 keV, followed by a fluorescence scan of the crystal itself.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/) Because the \\( f'' \\) peak and \\( f' \\) inflection are often separated by only a few eV out of 10,000 eV, MAD relies on a well-calibrated beamline with good energy resolution.[6](https://mol-xray.princeton.edu/xray0/Guides/MAD_example1.html)\n\nA MAD experiment typically collects data at three or four wavelengths: one at the \\( f'' \\) peak, one at the \\( f' \\) minimum (inflection), and one or more remote wavelengths, chosen to maximize the Bijvoet and dispersive differences.[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) These two difference types depend orthogonally on the phase angles, so strong differences in both are desirable for definitive phase determination.[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970) The signal strength is quantified by the Bijvoet diffraction ratio,\n\n\\[ \\frac{\\mathrm{rms}(\\Delta F_{\\pm h})}{\\mathrm{rms}(F_{P})} \\approx \\frac{\\sqrt{2}\\,\\sqrt{N_{A}}\\, f''}{\\sqrt{N_{P}}\\, Z_{\\mathrm{eff}}} \\]\n\nwhere \\( N_{A} \\) and \\( N_{P} \\) are the numbers of anomalous scatterers and total non-hydrogen atoms, and \\( Z_{\\mathrm{eff}} \\approx 6.7 \\) for proteins.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/) Recommended diffraction limits are better than 6 Å for at-resonance SAD and better than 3.5 Å for off-resonance native SAD, with high multiplicity at reduced dose and inverse-beam collection improving signal-to-noise.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/)\n\n## Origin\n\n[Isomorphous replacement](https://www.edgepedia.org/isomorphous-replacement) and anomalous scattering have been in use since the 1930s, with their most useful applications in macromolecular crystallography from the 1950s.[9](https://xrpp.iucr.org/cgi-bin/itr?url_ver=Z39.88-2003&rft_dat=what%3Dchapter%26volid%3DBa%26chnumo%3D2o4%26chvers%3Dv0001) The resonant scattering effect itself had been observed in the inorganic compound ZnS in the 1920s, and Bijvoet recognized that anomalous scattering could identify the correct enantiomorph of a noncentrosymmetric structure.[8](http://www.crystal.chem.uu.nl/~schreurs/reprints/GD3231.pdf) In 1951, Bijvoet, Peerdeman, and van Bommel determined the absolute configuration of sodium rubidium (+)-tartrate tetrahydrate, the first such determination for an organic compound, using monochromated Zr radiation (0.788 Å) close to the rubidium K-absorption limit at 0.814 Å, which gave \\( f' = 3.1 \\) and \\( f'' = 3.2 \\).[7](https://doi.org/10.1038/168271a0) • [8](http://www.crystal.chem.uu.nl/~schreurs/reprints/GD3231.pdf) Comparing 15 measured Bijvoet differences with values calculated from the structural model confirmed that the Fischer nomenclature assignment was correct.[8](http://www.crystal.chem.uu.nl/~schreurs/reprints/GD3231.pdf)\n\nThe synchrotron era transformed the method. Hendrickson and Teeter solved the structure of crambin directly from the anomalous scattering of sulfur in 1981,[10](https://doi.org/10.1038/290107a0) and Hendrickson's 1991 Science paper established multiwavelength anomalous diffraction with synchrotron radiation.[2](https://doi.org/10.1126/science.1925561) The first diffraction experiments with focused monochromatic synchrotron radiation, at SPEAR/SSRL on cesium hydrogen (+)-tartrate, measured a reduction in cesium scattering power of as much as 25 electrons per atom near the LIII edge.[11](https://escholarship.org/uc/item/78r179jw)\n\n## Variants\n\n**MAD and SAD** are the macromolecular workhorses. MAD measures several wavelengths around one edge, reducing the problem of solving thousands of atoms to solving a few anomalous centers used as a reference for the whole structure.[2](https://doi.org/10.1126/science.1925561) SAD uses a single wavelength and accounted for over 70% of de novo structures deposited to the Protein Data Bank in 2013.[3](https://www.nature.com/articles/ncomms13388) Two-color serial femtosecond crystallography at [SACLA](https://www.edgepedia.org/sacla) (7 and 9 keV) performs same-crystal two-wavelength MAD on microcrystals, with more accurate phases than single-color SAD and halved sample consumption.[12](https://www.nature.com/articles/s41467-017-00754-7)\n\n**DAFS** measures elastic Bragg reflection intensities versus photon energy, combining the long-range order sensitivity of diffraction with the short-range order sensitivity of absorption; in the extended region it yields EXAFS-like bond lengths, coordination numbers, and disorders, and in the near-edge region XANES-like valence information, with wavevector selectivity and site selectivity for inequivalent sites of one atomic species.[13](https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.69.3064) • [14](https://millenia.cars.aps.anl.gov/dafs/icas/) **AXS** denotes the quantitative anomalous scattering method for local chemical environments, introduced for amorphous thin films by Matsubara and colleagues in 1988 in the Transactions of the Japan Institute of Metals.[15](https://doi.org/10.2320/matertrans1960.29.697) **RXDS** (with its powder form P-RXDS) extracts site- and phase-selective spectroscopic information from DAFS measurements.[16](https://google.iopscience.iop.org/article/10.1088/1361-648X/aa53bb) The **anisotropy of anomalous scattering (AAS)** extends resonant diffraction, which distinguishes chemically identical atoms on different Wyckoff sites, to anisotropically scattering atoms to probe local orbitals.[17](https://onlinelibrary.wiley.com/doi/10.1002/crat.201300430) **Bijvoet-difference Fourier syntheses** at peak energies associate elemental identity with specific sites in metalloproteins.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/)\n\n## Applications\n\nIn protein crystallography, selenium-substituted (SeMet) crystals are phased at the Se K edge, and native sulfur SAD exploits the intrinsic sulfur signal without derivatization.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/) At X-ray free-electron lasers, Se-SAD solved streptavidin–selenobiotin to 1.9 Å at 12.8 keV,[3](https://www.nature.com/articles/ncomms13388) and thaumatin microcrystals were phased de novo using only endogenous sulfur atoms at 6 keV.[18](https://www.osti.gov/servlets/purl/1307373) In materials science, the quantitative AXS method determines the local environment around a specific atom in thin multicomponent films, applied to a 0.3 µm Bi-Fe-Ca-O oxide film.[15](https://doi.org/10.2320/matertrans1960.29.697) P-RXDS targets practical materials including antisite-defect electrode materials for lithium-ion batteries,[16](https://google.iopscience.iop.org/article/10.1088/1361-648X/aa53bb) and operando anomalous powder diffraction pinpoints active sites in catalysts such as Cu–MAZ zeolites.[19](https://wrap.warwick.ac.uk/id/eprint/193583/1/Journal%20of%20Applied%20Crystallography%20-%202025%20-%20Wardecki%20-%20Operando%20anomalous%20X%E2%80%90ray%20powder%20diffraction%20interleaved%20with%20X%E2%80%90ray.pdf)\n\n## Limitations and alternatives\n\n[Radiation damage](https://www.edgepedia.org/radiation-damage) is a central constraint: in sulfur SAD on thaumatin at 8 keV, \\(\\langle I/\\sigma(I) \\rangle \\) drops to about half its initial value after 8–12 full rotations, corresponding to roughly 5–8 MGy absorbed, and doses of 4–5 MGy keep damage tolerable.[20](https://journals.iucr.org/s/issues/2017/01/00/xh5051/xh5051.pdf) Damage appears first as reduction of metal centers, then cleavage of disulfide bonds and decarboxylation of aspartates and glutamates.[20](https://journals.iucr.org/s/issues/2017/01/00/xh5051/xh5051.pdf) Edge choice is restricted: the sulfur and phosphorus K edges lie at 5.02 Å and 5.78 Å, far beyond the 0.9–2.5 Å range of standard beamlines, so native SAD signals are very small at conventional wavelengths; a long-wavelength in-vacuum experiment at 4.96 Å reached a Bijvoet ratio of 8.8% for thaumatin but delivered 11.4 MGy, still within the 20 MGy Henderson limit.[21](https://www.sciencedirect.com/science/article/pii/S0168583X16305341) Other complications are inadequate anomalous strength, poor crystal order, small crystals, and the fluorescence, absorption, and background-shift corrections that anomalous small-angle experiments require when the wavelength is changed.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/) • [22](https://www.osti.gov/servlets/purl/5483971)\n\nAgainst alternatives, anomalous methods use the identical sample for all measurements, in effect providing perfect isomorphous replacement, unlike isotopic substitution in neutron small-angle scattering.[22](https://www.osti.gov/servlets/purl/5483971) MAD and SAD have displaced multiple isomorphous replacement, which dominated the first decades of protein crystallography, precisely because the crystal is the same at each wavelength, avoiding imperfect isomorphism.[1](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970)\n\n## References\n\n1. [Anomalous diffraction in crystallographic phase evaluation](https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/anomalous-diffraction-in-crystallographic-phase-evaluation/6AC7B9F432AA6482FD1ED9EC8655E970)\n2. [Wayne A. Hendrickson (1991). Determination of Macromolecular Structures from Anomalous Diffraction of Synchrotron Radiation. Science.](https://doi.org/10.1126/science.1925561)\n3. [Selenium single-wavelength anomalous diffraction de novo phasing using an X-ray-free electron laser](https://www.nature.com/articles/ncomms13388)\n4. [Multiwavelength anomalous diffraction analysis at the M absorption edges of uranium](https://www.pnas.org/doi/10.1073/pnas.191003998)\n5. [Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541782/)\n6. [Structure Determination using MAD - Example #1 (Princeton)](https://mol-xray.princeton.edu/xray0/Guides/MAD_example1.html)\n7. [J. M. BIJVOET, A. F. PEERDEMAN, A. J. van BOMMEL (1951). Determination of the Absolute Configuration of Optically Active Compounds by Means of X-Rays. Nature.](https://doi.org/10.1038/168271a0)\n8. [Redetermination of sodium rubidium (+)-tartrate tetrahydrate from Bijvoet's first absolute-configuration experiment](http://www.crystal.chem.uu.nl/~schreurs/reprints/GD3231.pdf)\n9. [International Tables for Crystallography: Isomorphous replacement and anomalous scattering](https://xrpp.iucr.org/cgi-bin/itr?url_ver=Z39.88-2003&rft_dat=what%3Dchapter%26volid%3DBa%26chnumo%3D2o4%26chvers%3Dv0001)\n10. [Wayne A. Hendrickson, Martha M. Teeter (1981). Structure of the hydrophobic protein crambin determined directly from the anomalous scattering of sulphur. Nature.](https://doi.org/10.1038/290107a0)\n11. [Edge anomalous scattering of cesium measured with synchrotron radiation (SSRL/SPEAR experiment)](https://escholarship.org/uc/item/78r179jw)\n12. [Multi-wavelength anomalous diffraction de novo phasing using a two-colour X-ray free-electron laser with wide tunability](https://www.nature.com/articles/s41467-017-00754-7)\n13. [Diffraction anomalous fine structure: A new x-ray structural technique](https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.69.3064)\n14. [Diffraction anomalous fine structure: DAFS](https://millenia.cars.aps.anl.gov/dafs/icas/)\n15. [Eiichiro Matsubara and colleagues (1988). A New Quantitative Anomalous X-ray Scattering Method for the Structural Analysis of Amorphous Thin Films. Transactions of the Japan Institute of Metals.](https://doi.org/10.2320/matertrans1960.29.697)\n16. [Site- and phase-selective x-ray absorption spectroscopy based on phase-retrieval calculation](https://google.iopscience.iop.org/article/10.1088/1361-648X/aa53bb)\n17. [Probing a crystal's short-range structure and local orbitals by Resonant X-ray Diffraction methods](https://onlinelibrary.wiley.com/doi/10.1002/crat.201300430)\n18. [Protein structure determination by single-wavelength anomalous diffraction phasing of X-ray free-electron laser data](https://www.osti.gov/servlets/purl/1307373)\n19. [Operando anomalous X-ray powder diffraction interleaved with X-ray absorption spectroscopy using a scanning 2D imaging detector on the XMaS beamline](https://wrap.warwick.ac.uk/id/eprint/193583/1/Journal%20of%20Applied%20Crystallography%20-%202025%20-%20Wardecki%20-%20Operando%20anomalous%20X%E2%80%90ray%20powder%20diffraction%20interleaved%20with%20X%E2%80%90ray.pdf)\n20. [Identification of the point of diminishing returns in high-multiplicity data collection for sulfur SAD phasing](https://journals.iucr.org/s/issues/2017/01/00/xh5051/xh5051.pdf)\n21. [Long-wavelength macromolecular crystallography – First successful native SAD experiment close to the sulfur edge](https://www.sciencedirect.com/science/article/pii/S0168583X16305341)\n22. [Anomalous small angle scattering (review/report)](https://www.osti.gov/servlets/purl/5483971)\n\n---\n*Topic: Encyclopedia › Physical world and mathematics › Physics › Matter and radiation physics › Condensed matter physics › Crystal and structural condensed matter*\n\n*Initially written Sep 29, 2026 · Edited: Oct 15, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/anomalous-x-ray-scattering", "markdown_url": "https://www.edgepedia.org/anomalous-x-ray-scattering.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Anomalous X-ray scattering\", Edgepedia (EdgeChat), https://www.edgepedia.org/anomalous-x-ray-scattering. Edgepedia Community License 1.0.", "credit_md": "\"[Anomalous X-ray scattering](https://www.edgepedia.org/anomalous-x-ray-scattering)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/anomalous-x-ray-scattering](https://www.edgepedia.org/anomalous-x-ray-scattering). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Anomalous X-ray scattering\", Edgepedia (EdgeChat), https://www.edgepedia.org/anomalous-x-ray-scattering. Edgepedia Community License 1.0.", "speakable": "Anomalous X-ray scattering is a diffraction technique that tunes X-ray energy near an element's absorption edge, making its scattering factor complex for element-specific structure and phase information." }