First diffraction peak

Person 1 Use Bragg s Law [Eqnation (1.35)] to calculate the rf-spacing (in nm) for the first diffraction peak in hydroxyapatite. Assume a first-order diffraction and an X-ray source of k = 0.1537 nm. 

Combine your information to determine the Miller indices of the first diffraction peak for hydroxyapatite. 

Information about disorder comes also from the position of the first diffraction peak, which defines the inter-planar spacing. The K values of the first diffraction peak are 1.675 A"... 

A radial section through a CD showing the rows of pits as a diffraction grating, the positioning of the detectors at the first diffraction peak, and the oblique path of the plane-polarised light. 

SAXS measurements showed that once Na-DFC was solubilized (even in low levels) the diffraction-scattering reflection intensities were higher (and better resolved) than those of the empty samples. The first diffraction peak appeared at the higher q values (0.0583, 0.0622, 0.0629, and 0.0661 for 0, 0.1, 0.2, and 0.4 wt% Na-DFC, respectively). These results indicated a decrease of d value due to partial dehydration of the headgroups as the Na-DFC content increased without a significant change in the cubic space group. 

Many factors which might affect the coprecipitation products were examined, i.e., the adipate concentration, the Mg/Al ratio, and the reaction temperature. As the mole ratio of adipate/Al in the solution varied in the range of 17.6 to 0.25, little change was found in the intensity of the first diffraction peak and the basal spacing (Fig. 8.2 (a)-(e)). This result is quite different from what is observed in method lA, where the diffraction peaks become broader as the concentration of adipate salt is decreased. 

It is concluded from table 1 that for most of the samples only the first diffraction peak, which implies sinusoidal composition modulation, is observed for the bilayer thicknesses A <30 A. This implies that R/T multilayers with thin layers have diffuse interfaces and... 

The assignment of the first diffraction peak to interchain and the second one to intrachain correlation is further supported by the different temperature dependence of both the... 

Therefore, the first diffraction peak has a much more pronounced temperature dependence compared to the second one (see Figure 1). 

Moreover, it is noteworthy that the intensity of the first diffraction peak decreases with decreasing temperature. This seems to be a general phenomenon of amorphous systems although its molecular origin has not been wdl understood up to the present. 

Figure 2 (a) Position of the first diffraction peak (interchain correiations) vs. temperature for fuiiy deuterated poiybutadiene. Soiid symbois ... 

M = 9.5 X 10 g moi open symbois /14 = 5.0 x 10 g moi". Lines are guides to the eyes. The data were taken from Frick, B. Richter, D. Ritter, Ci. Europhys. Lett. 1989, 9, 557. (b) Fuii width at haif maximum r of the first diffraction peak vs. temperature for fuiiy deuterated poiybutadiene. Soiid symbois /l4/ = 9.5 x lO g moM open symbois /14/ = 5.0 x 10 g moi The dashed iines are guides to the eyes. The dotted iine indicates a hypothetical equiiibrium vaiue for r in the giassy state. The data were taken from Frick, B. Richter, D. Ritter, Ci. Europhys. Lett 1989, 9, 557. ... 

---