Diffraction patterns from ciystals

Figure 10.7 Diffraction from small crystal volumes. This example is an SR Laue diffraction pattern from a (20 tm)3 ciystal of gramicidin. From Hedman et al (1985) with permission.

Figure 8.3 Single ciystal synchrotron X-ray diffraction patterns recorded from a variety of macromolecular crystals illustrating the variety of diffuse scattering features, (a) aPP, resolution limit 1.8A, wavelength 1.49A, 4.9° oscillation photograph. (b) RNAse, resolution limit 1.9 A, wavelength 1.488 A, still exposure.

Fig. 1 a shows a section of a Laue diffraction pattern of a LSGMO ciystal detected at room-temperature with a ciystal-detector distance of < 58 mm after the 4 thermal cycle. The Laue pattern shows multiplets splitting into 4 reflections, each one generated by Bragg reflections from its corresponding orientation state. The symbols TOl, T02, T03 and T04 (Fig. la) indicate different ferroelastic orientation states and corresponding reflections. 

A reaction of lead acetate and thioacetamide in addition with eetyl-trimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) at 80 °C yielded star fish like lead sulfide nanociystals. In this reaetion CTAB was dissolved in ethanol and then SDS was dissolved into it. To this mixture, acetic acid, lead acetate and thioacetate were added. The resultant solution was transferred into a stainless steel autoelave, which was heated to 80 °C for 24 h. Selected area electron diffraction (SAED) pattern from the star shaped PbS ciystals imaged along [111] zone axis indicated the arms of star shaped PbS have grown along [100] direction. Authors have studied the effect of reaction temperature and lead source on the morphology of PbS and they have concluded that 80 °C and lead acetate only yielded star-shaped PbS crystals. 

Crystals transited from liquid-ciystals can generate many more diffraction peaks corresponding to more crystalgraphic planes. Oddly, XRD pattern reveals more orders on the hepatic crystals. 

In the X-ray pattern for "HCOOH sol" Hf02 films fired at temperatures below 560 °C, only halo patterns representing the amorphous state were observed. At 560 °C [Fig. 12(a)], a small diffraction peak was observed at 2d = 28° in the halo pattern. At 570 °C, the diffraction peak at 26 = 28° became clearer and higher, indicating that partial crystallization from the amorphous state commenced at 560 °C. The observed diffraction peak was identified to correspond to monoclinic (111) (JCPDS card) and full ciystallization was attained at 700 °C. 

Figure 5.9 SEM micrographs of Sn02 NWs after the AAO template was (a) partially and (b] totally removed by immersing in 0.5 and 1 M NaOH solution for 2 h and 4 h, respectively (c] TEM of single Sn02 wire the inset is the selected area electron diffraction (SAED) pattern of the single-ciystal Sn02 NW in (c) (d] HRTEM micrograph of the area marked in (c] with a square. The black arrow indicates the in situ formed thin layer. Reprinted with permission from Ref 63. Copyright 2008 American Chemical Society.

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