Hi Peter,
Can you try to run xtriage and see what it tells you in terms of
possible twin laws and merging statistics in higher symmetry space
groups?
The log file is attached. xtriage does not find any clear signs of
pseudosymmetry or higher metric symmetry, but it does detect the
Frankly when faced with these problems of generating symmetry
equivalents i revert to almn, where a) I can guarantee the
orthogonalisation is as I expect, and b) it generates an exhaustive set
of symmetry equivalent peaks.
But that is old technology..
If you have two dimers in the asymmetric
we have NCS rotation (158.56, 180, 0) - rotation matrix [R]
and we have two CS operators (P21) - rotation matrix (0 0 0) [1]
and (90 90 180) [2].
So, all symmetry related (for [R]) rotations are
[1][R][1] = [R] - (158.56, 180, 0)
[1][R][2] = [R][2] - ( 111.44 0.0 180.0)
[2][R][1] = [2][R] - (
Hi everyone,
Can anyone help me with interpretation of a self rotation function and
native Patterson from a dataset with pseudosymmetry? I've always been
a bit poor on spherical polars. The space group is P21 with beta =
92.2°. The kappa=180° section of the SRF, calculated using Molrep, is
Hi Derek,
The assymertic unit of the self rotation function is only one
hemisphere, for example the north hemisphere.
So, if you look on the kappa = 180 °, horizontally in the equator you
have the crystallographic axis and 2 perpendicular 2-fold axis on to the
other, the one in the near
1) It is a bit hard to find out how MOLREP defines its orthogonal axes -
many programs use X0 || a, Yo || b* and in P21 hence Zortho is || to c*
If that is what Molrep does then your 2 fold is in the a c* plane, 21
degrees or 111 degrees from c*.
The 2 peaks you see are symmetry equivalents.
Peak (21.44, 0, 180) has symmetry-related peak (111.44 0 180).
These two peaks are identical because NCS peak (21.44, 0, 180) is
pependicular to CS peak (90 90 180)
Two perpendicular 2-fold peaks (NCS and CS) generate
additional 2-fold axis (111.44 0 180). It's called Klug peak.
Regards
Alexei
Hi Derek
The symmetry of the self-RF is explained in detail in the documentation for
POLARRFN, in fact I would advise you to use this because you can then plot
monoclinic space groups with the unique b axis along the orthogonal Z axis
(NCODE = 3) and then the symmetry is *much* easier to
correction:
Peak (21.44, 0, 180) has symmetry-related peak (158.56 180 180).
.
On 23 Apr 2008, at 13:39, Derek Logan wrote:
Hi everyone,
Can anyone help me with interpretation of a self rotation function
and native Patterson from a dataset with pseudosymmetry? I've
always been a
Thanks to everyone who helped with the self RF problem: Eleanor, Ian,
Claudine, Pietro Alexei.
Eleanor wrote:
1) It is a bit hard to find out how MOLREP defines its orthogonal
axes - many programs use X0 || a, Yo || b* and in P21 hence Zortho
is || to c*
If that is what Molrep does then
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