Zur Theorie der Absorption und Dispersion in den R�ntgenspektren

Kronig, R. de L.; Kramers, H. A.

doi:10.1007/bf01351301

Cited by 124 publications

(32 citation statements)

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“…The quantum dispersion theory (Kramers and Heisenberg, 1925) was extended to analysis of the refraction, absorption and dispersion of x-rays (Kronig, 1926; Kronig and Kramers, 1928). The most complete quantum elaboration came in the theory of Hönl (1933), which used atomic wave functions to obtain oscillator strengths and from them the photoelectric absorption cross-sections were needed to calculate scattering factor corrections.…”

Section: Historical Backgroundmentioning

confidence: 99%

Anomalous diffraction in crystallographic phase evaluation

Hendrickson

2014

Quart. Rev. Biophys.

126

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X-ray diffraction patterns from crystals of biological macromolecules contain sufficient information to define atomic structures, but atomic positions are inextricable without having electron-density images. Diffraction measurements provide amplitudes, but the computation of electron density also requires phases for the diffracted waves. The resonance phenomenon known as anomalous scattering offers a powerful solution to this phase problem. Exploiting scattering resonances from diverse elements, the methods of multiwavelength anomalous diffraction (MAD) and single-wavelength anomalous diffraction (SAD) now predominate for de novo determinations of atomic-level biological structures. This review describes the physical underpinnings of anomalous diffraction methods, the evolution of these methods to their current maturity, the elements, procedures and instrumentation used for effective implementation, and the realm of applications.

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Section: Historical Backgroundmentioning

confidence: 99%

Anomalous diffraction in crystallographic phase evaluation

Hendrickson

2014

Quart. Rev. Biophys.

126

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“…Small-angle scattering will depend on the anomalous contributions, as described by Eq. 4: [4] where 1U(h) = 2 ffpa(r)Psjr) sihIF -j d3rd3r'…”

Section: Methodsmentioning

confidence: 99%

“…From the previous data off andf", it is clear that Eq. 4 is simplified, as the quadratic term of p' and p" in Eq. 4 will be small compared with the crossterm, which is linear in p'.…”

Section: I(h) =mentioning

confidence: 99%

Configuration of the four iron atoms in dissolved human hemoglobin as studied by anomalous dispersion.

Stuhrmann¹,

Notbohm²

1981

Proc. Natl. Acad. Sci. U.S.A.

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The anomalous dispersion of iron at its K-absorption edge in small-angle scattering of an aqueous solution of hemoglobin has been used to establish the geometrical arrangement of the four iron atoms in this protein. Although the anomalous contributions are 0.001-0.01 of the total scattering, experiments with synchrotron radiation from the storage ring DORIS have shown that these effects can be measured with an average precision of =10% at each of the 50 points of the scattering curve. The anomalous scattering represents the convolution ofthe whole structure with the configuration of the four iron atoms of hemoglobin. Analysis in terms bf multipoles suggests that tetrahedral symmetry ofboth the subunit arrangement and the iron structure is a dominant feature. The mean distance between the iron atoms of 26 A derived from this experiment compares well with that derived from crystallographic data.

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“…Resonant scattering near an X-ray absorption edge is mainly due to one type of oscillator, f' and f" are connected by the Kronig-Kramers relation (Kronig & Kramers, 1928) (1980). The units of the atomic form factor are electrons.…”

Section: Introductionmentioning

confidence: 99%

A small-angle camera for resonant scattering experiments at the storage ring DORIS

Stuhrmann¹,

Gabriel²

1983

J Appl Cryst

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Resonant small-angle scattering is measured routinely in the wavelength range of 0"6 to 3"25 A with the instrument X15 at the storage ring DORIS. The monochromatic beam with a vertical offset of 1.22 m is achieved by a double monochromator system with a constant exit slit. The small-angle instrument allows for sample-detector distances between 0.37 and 7.33 m. A muitiwire proportional counter with a sensitive area of 200 x 200 mm detects the scattered intensity with a spatial resolution of 2 x 2 mm. Its sensitivity can be adapted to the requirements of the experiment by activating a drift chamber of 8 cm depth at the back end of the detector. The performance of the instrument as a function of the wavelength is described. The energy resolution is about 1 eV at the L 3 absorption edge of caesium, as shown by the resonant scattering of ferritin in 30% CsC1 solution.

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Zur Theorie der Absorption und Dispersion in den R�ntgenspektren

Cited by 124 publications

References 0 publications

Anomalous diffraction in crystallographic phase evaluation

Anomalous diffraction in crystallographic phase evaluation

Configuration of the four iron atoms in dissolved human hemoglobin as studied by anomalous dispersion.

A small-angle camera for resonant scattering experiments at the storage ring DORIS

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