(a) Difference in structure factor phases regarding the proposed models, as detailed in the inset (NH3 FG and N3e ). X-rays of 10 keV. (b) Three-beam cases predicted to show opposite profile asymmetries on each model structure according to the criterion . G = 261 and (NH3 and N3e ). Limited to amplitude W > 5%. dG,H is the interplanar distance of Bragg planes.