Figure 3 Significance of anomalous signal in a three-wavelength MAD data set (peak, edge, remote). (a) Normal probability plot of anomalous differences anom = (I+ - I-)/[2(I+) + 2(I-)]1/2 for each wavelength. The central slope indicates the strength of the anomalous signal relative to the estimated errors, Peak > Remote > Edge. (b) Correlation coefficients between pairs of different wavelengths: filled circles, peak to edge; diamonds, edge to remote; open circles, peak to remote. The dashed line is the correlation coefficient between dispersive differences, peak-remote to edge-remote. (c) Correlation coefficients between random half data sets with the peak data set: filled circles, anomalous differences (acentric); open circles, Bijvoet differences for centric data (should be 0); diamonds, <I>, showing decrease in the quality of the intensities themselves at high resolution.

© International Union of Crystallography 2006