My experience with pseudo-merohedral twinning (it was actually the
reticular case with half the spots overlapped and the other
non-overlapped half on a pseudo C-centred lattice) is that the degree
of splitting varies widely over the diffraction pattern. In some
places there was complete overlap, in others you see elongation of the
spots, in others partial separation, and in others complete separation
(and of course all shades in-between), with around 50-50 intensity
split. In this situation the mosaicity becomes meaningless! I'm not
aware of any software that can handle this kind of thing successfully
(and certainly the data we did manage to get turned out to be
garbage!).
Both DIRAX or SAINT should be able to handle it, you'll need SADABS to
scale it. (The latter two are in the Bruker software.)
phx.
