Trigonal space groups have a choice of two arbitrary "settings."
Were all those 180 frames collected in one pass? What were the
integration statistics?
What was the phasing method? Did you have a pre-existing structure*,
molecular replacement, anomalous, or what?
* This is the one I am concerned about. If you had a pre-existing
structure in this same crystal form, but then used some newly collected
data, it may not be in the same setting as the original.
On 01/23/12 16:48, Sam Arnosti wrote:
Hi every one
I have some crystals in the space group P3121. I collect 180 frames of data.
My crystals do not diffract better than at most 2.0 angstrom, but the Rf barely
goes below 23%,
and Rfree also remains somewhere between 28-33%. I have tried to refine my data
as much as I can.
I do not know whether the problem is because of the bad diffraction or
collecting extra frames.
The structure factors are also high but they get better as the crystals
diffract better.
Thanks
Sam
--
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All Things Serve the Beam
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David J. Schuller
modern man in a post-modern world
MacCHESS, Cornell University
schul...@cornell.edu
