scholarly journals Coherent X-ray Scattering by Co III

1985 ◽  
Vol 38 (4) ◽  
pp. 609
Author(s):  
R Glass
Keyword(s):  
Ground State ◽  
Open Shell ◽  
Sufficient Accuracy ◽  
X Ray ◽  
Hartree Fock ◽  
X Ray Scattering ◽  
Atomic Scattering Factor ◽  
Atomic Scattering ◽  
Scattering Factor ◽  
State Configuration

The atomic scattering factor for the ground state of the cobalt ion, 3d7 4F, has been evaluated using nonrelativistic and 'relativistic-corrected' wavefunctions of varying accuracy. The importance of incorporating all types of electron correlation systematically within the valence subshell while keeping a fixed argon core is discussed. From the results presented, it appears that atomic scattering factors evaluated using Hartree-Fock wavefunctions are of sufficient accuracy for an atomic ion with an open-shell ground-state configuration.

Coherent X-ray Scattering Factors for Various Configurations of Lanthanides and Their Positive Ions

1975 ◽  
Vol 53 (1) ◽  
pp. 93-96 ◽  
Author(s):  
Robert Benesch ◽  
K. M. S. Saxena
Keyword(s):  
Ground State ◽  
Wave Functions ◽  
X Ray ◽  
Hartree Fock ◽  
Positive Ions ◽  
X Ray Scattering ◽  
Scattering Factor ◽  
Ray Scattering

Coherent X-ray scattering factors have been computed from numerical Hartree–Fock wave functions for the neutral lanthanides and for their single-, double-, and triple-positive ions having the most commonly occurring 6sm4fn ground state configurations. For small scattering angles, the scattering factors for the ions vary among the various configurations. At large scattering angles all configurations for a given ion yield similar values for the scattering factor.

scholarly journals Calculation of The Imaginary Part of Atomic Form Factor For X-ray In Nickel

2019 ◽  
Vol 23 (10) ◽  
pp. 66
Author(s):  
Ahmed Raheem Ahmed ◽  
, Muhsin Hasan Ali
Keyword(s):  
Imaginary Part ◽  
High Energy ◽  
Approximate Methods ◽  
X Ray ◽  
X Ray Scattering ◽  
Atomic Scattering Factor ◽  
Atomic Scattering ◽  
Scattering Factor ◽  
Atomic Form Factor ◽  
Good Agreement

In the present study, we calculated the imaginary part of the x-ray scattering factor of nickel based on the principles of quantum mechanics to find a wave function that describes the electronic state of atoms by approximate methods, observed the study suggested that in both low energy values , and at high energy values , the imaginary part is approximately zero, this means that the electrons are intensely connected to the atom, where in the spectrum the photon energies are approximately equal to the electron bonding energy  we note the study pointed out that the imaginary part of the atomic scattering factor become  prominent and the electron becomes highly absorbent, the relative accuracy varies within range (0.03-0.22)%, and there was also a good agreement between the behavior we obtained for the imaginary part of the atomic scattering factor and the behavior that was calculated using other models.    http://dx.doi.org/10.25130/tjps.23.2018.171

Calculation of scattering curves for macromolecules in solution and comparison with results of methods using effective atomic scattering factors

1983 ◽  
Vol 16 (1) ◽  
pp. 74-82 ◽  
Author(s):  
J. J. Müller
Keyword(s):  
Scattering Data ◽  
Structure Parameters ◽  
Wide Angle ◽  
X Ray ◽  
Rna Molecules ◽  
Dna And Rna ◽  
X Ray Scattering ◽  
Atomic Scattering Factor ◽  
Atomic Scattering ◽  
Scattering Factor

An improved cube method was developed for the computation of X-ray scattering curves of macromolecules in solution. For double-helical DNA and RNA molecules the efficiency of this method is shown. The results are compared with curves calculated by effective atomic scattering factor methods. In the small-angle and in the wide-angle regions the improved cube method is superior to the effective atomic scattering factor methods. This was proved by the calculation of structure parameters and by a comparison with experimental scattering data. On the basis of the improved cube method, models with a reduced structure resolution are deduced for DNA and RNA molecules. The models consisting of the three scattering centres phosphate, sugar and base per nucleotide are equivalent in scattering to the real structure up to a scattering angle of about 0.15 rad for copper radiation.

X-ray Scattering Factors of Ions in Crystals

1979 ◽  
Vol 34 (12) ◽  
pp. 1471-1481 ◽  
Author(s):  
P. C. Schmidt ◽  
Alarich Weiss
Keyword(s):  
Gaseous Phase ◽  
Form Factors ◽  
Negative Ions ◽  
X Rays ◽  
Charged Sphere ◽  
Sphere Model ◽  
X Ray ◽  
Hartree Fock ◽  
X Ray Scattering ◽  
Atomic Scattering

AbstractThe atomic scattering factors for X - Rays are given for the ions Li⊕, Be2⊕, B3⊕, C4⊕, N5⊕, N3⊖, O2⊖, F⊖, Na⊕, Mg2⊕, Al3⊕, S2⊖, Cl⊖, K⊕, Ca2⊕, Sc3⊕, Ti4⊕, V5⊕, Ni, Cu⊕, Zn2⊕, Ga3⊕, Se2⊖, Br⊖, Rb⊕, Sr2⊕, Y3⊕, Pd, Ag⊕, Cd2⊕, I⊖, Cs⊕, and Ba2⊕ in the crystal. The crystal potential is simulated by a hollow charged sphere (Watson sphere model). The Hartree-Fock-Roothaan-method was used for the calculation. The crystal field affects most strongly the atomic form factors of the negative ions, especially the twofold and threefold ionized negative ions, which are unstable in the gaseous phase.

Anomalous x-ray atomic scattering factor for Zr, Nb, and Mo

1989 ◽  
Vol 40 (9) ◽  
pp. 5420-5421
Author(s):  
M. S. Wang ◽  
Sheau-Huey Chia
Keyword(s):  
X Ray ◽  
Atomic Scattering Factor ◽  
Atomic Scattering ◽  
Scattering Factor

scholarly journals The atomic scattering factor for X-rays in the region of anomalous dispersion

1933 ◽  
Vol 139 (838) ◽  
pp. 459-466 ◽  
Keyword(s):  
Free Electron ◽  
Scattered Radiation ◽  
Wave Length ◽  
Anomalous Dispersion ◽  
X Rays ◽  
Characteristic Frequencies ◽  
X Ray ◽  
Atomic Scattering Factor ◽  
Atomic Scattering ◽  
Scattering Factor

The atomic scattering factor ( f -factor) for X-rays is the ratio of the amplitude of the X-rays scattered by a given atom and that scattered according to the classical theory by one single free electron. It is given as a function of sin ϑ/λ, λ being the wave-length of the X-rays, 2ϑ the angle between the primary and the scattered radiation. It is assumed to be independent of the wave-length so long as sin ϑ/λ remains constant. Recently, however, it has been shown both theoretically and experimentally that the last assumption is no longer valid, when the scattered frequency is in the neighbourhood of one of the characteristic frequencies of the scattering element. The first to show the influence of the anomalous dispersion on the f factor were Mark and Szilard, who reflected strontium and bromine radiations by a rubidium bromide crystal. Theoretically the problem was dealt with by Coster, Knol and Prins in their investigation of the influence of the polarity of zincblende on the intensity of X-ray reflection and later on once more by Gloeker and Schäfer.

Modelling of cation displacements in SrTiO3by means of multi-energy anomalous X-ray diffuse scattering

2016 ◽  
Vol 49 (3) ◽  
pp. 1016-1020 ◽  
Author(s):  
Miloš Kopecký ◽  
Jan Fábry ◽  
Jiří Kub
Keyword(s):  
Absorption Edge ◽  
Diffuse Scattering ◽  
Ambiguous Information ◽  
X Ray ◽  
Two Photon ◽  
Atomic Scattering Factor ◽  
Atomic Scattering ◽  
Scattering Factor

X-ray diffuse scattering of SrTiO3has been measured at two photon energies, the first just below the absorption edge and the second far from theKabsorption edge of strontium, in order to vary the atomic scattering factor of the strontium cations. It is shown that two different models of cation displacement comply with the single-energy diffuse scattering patterns, because single-energy diffuse scattering provides only ambiguous information on the directions of displacement of the Sr2+and Ti4+cations. However, the application of multi-energy anomalous diffuse scattering determines unambiguously that the Sr2+cations are moved from their ideal positions in the [100] direction and the Ti4+cations are shifted in {111} directions.

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