R1Q7 unit cell parameters determination

[dagewa]

Page 13-14 unit cell parameters determination – ED data is known for large deviations of reflection positions from their expected coordinates – therefore different clustering routines were adopted in the unit cell search procedures. How scattered were the data used, how good different algorithms performed?

[dagewa]

Reply: It is possible that the discussion regarding different indexing methods available in DIALS confuses this section. These methods are all described in the DIALS general reference and don't need to be repeated here as we simply used the default FFT3D in each case. We have edited the section to remove the discussion of different algorithms. We do not report the deviation of expected from observed positions immediately after indexing in the manuscript, because this represents an intermediate stage in the modelling of the diffraction experiment. It is better to report the final RMSDs after the final step of geometry refinement. At that point, a more sophisticated model incorporating unit cell, orientation and beam direction drift has been determined. These values are included in Table 1. It can be seen that all datasets have sub pixel RMSDs. Angular deviation is less than 0.1 degree in all cases, except for dataset 6, which had RMSD in Z close to 0.5 degree. As discussed in the text, this dataset showed relatively poor diffraction.