(color online) (a) Comparison of the data derived directly from the experimental image shown in Fig. 5(a) (solid circles) with those derived from the best fitting simulated image shown in Fig. 5(b) (open squares) for the peak intensity at atomic positions. (b) The difference δ_Pos in positions of the intensity maxima between the experimental and the simulated images for x (squares) and y (circles) directions. The standard deviation (SD) for the position difference is 0.5 pm for both x and y directions. The indexes i, j of the intensity maxima are referred to those in Fig. 5.^[12]