Guinier diffraction

A. Guinier, Diffraction In Crystals, Imperfect Crystals, and Amorphous Bodies, Dover, New York, 1963. 

Figure 2.15. High-resolution Guinier diffraction scans over the principal iron line of partly activated samples. We note the intensity between the two clear peaks in both diffraction patterns which indicate the presence of an additional phase during activation.

Investigations for the occurrence of polymorphism have been undertaken by ir spectroscopy, differential scanning calorimetry and x-ray powder diffraction (Guinier-de Wolff). No polymorphism has been observed so far. An amorphous form may be prepared artificially by rapid evaporation of a methanolic solution of the drug substance. 

A. Guinier, X-Ray Diffraction In Crystals and Amorphous Bodies, Freeman, San Francisco, 1964. 

The method of Simpson and Steinfink (4, 5) which uses liquid scattering functions was employed to take into account the unlocated atoms, assuming that they are uniformly distributed throughout a sphere. Atomic parameters were refined with 235 structure factors corresponding to all reflections with h2 + k2 + l2 <396 except the 111 line. A Guinier-type camera with monochromatized Cu K i radiation was used because of its low background diffusion, to detect the broad diffraction fines of external... 

The distribution of cations in AH 200 is very similar to that found with AH 25, and thus the amount of reduced palladium remains unchanged. This result is not surprising because water molecules subsequent to the reduction of the first five atoms are still bonded to the cation at this temperature, and prevent subsequent reduction as suggested above. Besides, very weak and broad diffraction lines observed on Guinier photographs indicate a beginning of Pd(0) migration toward the zeolite external surface. 

Guinier, A. (1963). X-ray diffraction. W. H. Freeman, San Francisco. Reprinted by Dover, New York. 

Several octahedral crystals were ground to powder and studied by the Guinier-Hagg technique (Cu radiation). All diffraction lines could be indexed on the basis of a cubic cell with a = 4.560 0.001 A., which is within experimental error of that reported previously for MnSi, 4.558 0.001 A.2 In view of the similarity of the cell constants of the ground crystals to those of previous preparations, significant replacement of manganese by copper is not indicated. This was checked on a few crystals by emission spectrographic analysis which indicated an upper limit of ca. 1% of copper. 

It will be assumed here that the X-ray diffraction data were collected on flat films with a point focus camera. This simplifies the theoretical presentation. The TMV data analyzed in the results section were collected on cylindrical films with Guinier cameras, but positions on the cylindrical films can be mapped onto positions on a flat film by a simple geometric transformation. In general, the form of the optical density, D(r,), in a fiber diffraction pattern can be expressed in film coordinates as the sum of contributions from all reflections, I (r,iJ> ), plus a background term, B(r,) ... 

Figure 2 shows the results of the non-linear fitting procedure on a part of the equator, first and second layer lines of TMV. The diffraction pattern used was taken by Dr. S. Warren and Dr. G. Stubbs at the Max-Plank-Institut in Heidelberg, Germany. This pattern was taken on a Guinier camera and the arcsdue to disorientation are not circular. The natural coordinate system (3)of the camera (rather than polar coordi-nates)was used in the deconvolution procedure. The standard... 

Samples of purified EuC12 were analysed for europium and chlorine by conventional analytical methods. Calc for EuC12 Eu, 68.18%. Found Eu, 68.1 x +0.2i Cl, 31.80+0.02. X-Ray diffraction patterns of the polycrystalline samples and residues from the vaporization experiments, to which an internal Pt standard (a = 3.9238 +0.0003 A) had been added, were obtained with a Haegg-type Guinier camera and Cu Ka radiation. The lattice parameters and intensities of the diffraction lines were in agreement with those reported (1) for orthorhombic EuC12 (PbCl2 structure). 

Guinier, A. (1939). La diffraction des rayons X aux tres petits angles Application a l etude de phenomenes ultramicroscopiques. Ann. Phys. (Paris) 12, 161—237. 

X-ray powder diffraction investigations were made in cooperation with P. Norby (Oslo University) and I.G. and E. Krogh Andersen (Odense University). For phase identification and lattice costants determination a Guinier-Hagg camera has been used (CuKa =1.5451 (10) quartz internal standard a=4.91309 A, c=5.40426 A (11). The diagrams were indexed and lattice constants refined by least square... 

A. Guinier, Intermediary States between Order and Disporder. In Diffraction Studies on Non-Crystalline Substances, I. Hargittai, W. J. Orville Thomas, eds., Elsevier, Amsterdam, 1981, pp. 411 138, p. 413. 

Fig. 5.6 XRD powder diffraction pattern (microdensiiomctcr trace of Guinier film CuK , radiation spacings in A) of a fully reacted P-CjS paste. Mohan and Taylor...

X-ray Diffraction Studies. They are performed under vacuum with a Guinier type focussing camera equipped with a bent quartz monochromator giving a linear collimation of the CuK (X = 1.54 A) radiation (8). 

In simulating the observed diffraction pattern, however, large values of anisotropic thermal parameters (l/i,) were necessary for As and F atoms. The temperature dependence of the pattern obtained by the Guinier-Simon method (Fig. 8) indicates that the pattern essentially does not change up to 390 K. This hinted that there prevails considerable disorder already at room temperature. The fine structure at 300 K shown in Fig. 8(/>)... 

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