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
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