You can use Pointless to sort out the relative indexing of the two
files, but I have no idea how you get that information back into HKL2000
Phil
On 22 Oct 2009, at 16:19, Yuan Cheng wrote:
Hi everyone,
I have some question about the merging of diffraction data from
different crystals. I have two (room-temperature) datasets in my
hand and each of them can be scaled in P21 space group and the screw
axis is along k. However,each dataset only have below 55%
completeness. To get better completeness, I am trying to merge this
two datasets. The problem is one dataset has cell dimension
(80.632,87.085,114.977),(90,90.026,90) and the other one has
(85.497,79.857,114.003) (90,90.004,90),. It looks like that the a,b
dimensions are switched between these two datasets.
Unsurprisingly,the chi^2 is very high when I tried to merge these
two datasets in scalepack.I am wondering whether there is any way to
reindex these two datasets to make their a/b dimensions match. Any
suggestion will be highly appreciated.
By the way, as you might notice, the beta angle is pretty close
to 90 degree. I scaled the datasets into P212121 or P2221 or P21212
at the beginning,I had no trouble to merge them in these space
groups. However,I could not make the Rfree go below 45% during
following refinement (2.7 angstrom cutoff). Phenix.xtriage indicated
that there might exist twinning but no twin law is given. Then I
reindexed the data into P2 and scaled them in P21 SG.Phenix.xtriage
indicates there exists a pseudomerohedral twinning operator. When I
used the twin law given in phenix.refine,the Rfree could go down to
29%. So I think P21 might be the correct space group.
Thanks again for any suggestion.
Yuan
