Figure 5
The formation of a diffraction peak in an imperfect crystal represented by undulating planes due to defects. The atomic planes scatter intensity in a direction defined by the crystal truncation rod, the specular angle 2θ (red), and towards the enhancement angle 2θB (blue). The specular peak is therefore broad, appearing as background, and the enhancement peak is sharp. Only for those scattering directions where the specular and enhancement contributions overlap (purple) will the Bragg condition and dynamical effects become important. For imperfect crystals, this overlap becomes a small fraction and I = |Fhkl|2 is a reasonable assumption. |