A good compromise in the case of suspected perfect merohedral twinning
is to select the free R reflections using thin shells. Since the twin
related reflections have the same sin(theta)/lambda values they will
not be split over the working and reference sets. XPREP offers this
option. A disadvanta
you need to select the Free R in the highest possible Laue group , then
use cad to extend this to all reflections in the chosen point group.
This is best done immediately post-truncate..
eg if you twinning operator is k,h,-l, then if
1,2, 3 is assigned to the free set so should 2, 1, -3 be.
P
Am 5 Dec 2008 um 13:50 hat Agnieszka Kiliszek geschrieben:
> Hi,
>
> What is the meaning of R free of perfect twin? Shelxl counts it but it
> seems that the R f is no longer independent.
>
> Aga
Dear Aga,
I also had this problem, however with Refmac5.5.
My solution was to use the CNS script
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
I guess the independence is mostly depending on how you select the
reflection that lie in the free-set.
If (from the beginning) you select reflections that are related by the
twin operator to be both in the free-set you keep the "independence"
Hi,
What is the meaning of R free of perfect twin? Shelxl counts it but it
seems that the R f is no longer independent.
Aga
