 | Acta Crystallographica Section A Acta Crystallographica Section A FOUNDATIONS AND ADVANCES |
journal menu
![[Figure 10]](ae5046fig10mag.jpg)
|
|
Figure 10
The interaction of different shape functions with the Ewald sphere. A gives rise to peaks ac1 and ac2 where the tails touch the Ewald sphere; this is the interpretation based on the conventional theory. In the new theory there is another term [equation (4), Fewster (2014  )], so that three peaks appear an1, an2 and an3 (an3 is the enhancement peak) and there is also residual intensity associated with the whole of the shape function. The shape function given at B corresponds to the sample used in Fig. 8, i.e. for a crystal wafer with a truncation rod normal to the surface with a very short arm parallel to the surface. At this orientation the conventional theory predicts no peaks since no part of the shape function touches the Ewald sphere. The new theory predicts a peak at 2θB (bn1) for all orientations in Ω. The reciprocal-space map B can be compared with the measured data from Fig. 8 (inset) to show how a single extracted 2θ scan away from the Bragg condition forms enhanced intensity at 2θB. |
![[Figure 10]](ae5046fig10.jpg)
| FOUNDATIONS ADVANCES |
ISSN: 2053-2733
Open 
access
access
