Hello everyone,
I collected a x-ray crystal data at around 3-4A resolution and processed
with HKL2000.
The space group, P6, C2, C222, P2, P1, were possible when indexing.
I tried all these space groups.
However, when first cycle of scaling without using rejection, chi square
values of the lowest resolution shell (50-8 A) were very high (from 10 to
30).
>From next cycle, after use rejection, those chi square decrease to 2-3.
One example of results is below.
Shell Lower Upper Average Average Norm. Linear Square
limit Angstrom I error stat. Chi**2 R-fac R-fac
50.00 7.75 386.3 12.7 6.3 1.171 0.035 0.040
7.75 6.15 91.7 5.8 4.9 1.047 0.075 0.073
6.15 5.38 66.5 6.5 6.3 1.021 0.110 0.103
5.38 4.89 71.4 8.4 8.2 1.018 0.123 0.113
4.89 4.54 71.5 10.2 9.9 1.005 0.135 0.134
4.54 4.27 49.5 11.7 11.7 0.908 0.197 0.211
4.27 4.05 41.0 13.4 13.4 0.848 0.249 0.268
4.05 3.88 31.2 15.1 15.1 0.777 0.341 0.408
3.88 3.73 28.1 17.0 17.0 0.732 0.392 0.488
3.73 3.60 25.7 18.0 18.0 0.666 0.456 0.622
All reflections 90.0 11.7 10.8 0.978 0.093 0.064
It was difficult to adjust chi square, and the structure was not solved
using molecular replacement with all space groups, even with P1.
Is there any comments or recommendations about these unusual chi square?
Thank you,
Best Regards, Ki Joon Cho
