On 7/22/13 11:20 PM, Ethan Merritt wrote:
>
> Which brings up the point that something seems to have
> gone wrong in one of your processing runs.
> Both runs claim mean (I/sigI) in the outer shell is 2.0,
> but in one case this is for the 2.4A shell and in the other case
> it's for the 2.2A shell. That is unlikely to be correct.
> I/sigI should not depend on the Laue group.
>
Why is this surprising? This is what I would expect. By going to
orthorhombic, she is getting higher redundancy (two-fold more), and
hence higher I/sigI. She will also have fewer molecules per asu, and
less of NCS to help her with refinement if she sticks to orthorhombic.
But, other than that, yes, twin R factors should come with big warning
signs on them. Intensity moments, for example,
<I**2>/<I>**2 = 2.032
are showing no signs of twinning (and there is no translational NCS to
confuse the intensity stats), so the data should not have been treated
as twinned in the first place. I agree with Ethan that at first sight,
it appears orthorhombic.
Engin
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