Figure 1
The new theory in terms of the Ewald sphere construction. All the reciprocal-lattice points coloured blue can form intensity for this given incident angle at their respective 2θB [subject to the conditions contained in Fewster (2014), i.e. 0 < Ω < 2θB]. The distance of the reciprocal-lattice point to the surface of the Ewald sphere along the arc in Ω defines its amplitude. The amplitude decreases as the distance increases, e.g. 03 is in the Bragg condition and the amplitude is at its maximum value, whereas 002 is weaker and 03 is very weak etc. The arcs drawn for some of the reflections give a guide to judge the strength of the scattering by the distance along the arc from the Ewald sphere maximum value. We can consider the Ewald sphere surface to have a thickness with a profile given by Fewster [2014, equation (4)]. |