Yes - that is true.
Any crystal might be split, and give diffraction with overlapping
lattices- ie show non-merohedral twinning. If you are lucky/careful you
might only get a few spots which overlap after integration of one of the
lattices- not enough to be detected as "twinning" from the statistical
analysis...
but the SG R3 is a classic one for merohedral twinning with operator k,h,-l
Have you looked at the scala log file - you need to check the L test for
twinning, whether there is non-crystallographic translation etc.. as
well as looking at the moment plots.
Eleanor
On 04/06/2011 05:08 PM, ka...@ssl.serc.iisc.ernet.in wrote:
Dear users,
Is there a possibility that both non-merohedral twinning
and partial hemihedral twinning occur in the same crystal?
In one of the data in R3, sfcheck indicated twinning and thus
upon using twinning option during refinement, refmac considered
twinning operator of (k h -l). But the images also show some
interpenetrating lattice spots which are characteristics of
non-merohedral twinning.
Probably one of the lattices have been more prominent
and hence detected and processed by mosflm with an overall
Rmerge of 8.2 at 2.35 Ang resolution.
So is there such a possibility?
Thanking you
With Regards
Kavya
