Orientation matrices conventions

The crystal orientation matrices are defined in reference to a particular coordinate system, which is different in Mosflm, Denzo and XDS. This document tries to summarize the necessary informations to convert matrices from one coordinate system to the other. Note: Mosflm and Denzo are using to distinct coordinate systems for the gogniosta and the detector (the X and Y axis of the detector are not the same that defines the crystal orientation).

MOSFLM

The crystal orientation matrix is defined relative to the camera (goniosta) coordinate frame. See the complete definition at http://www.mrc-lmb.cam.ac.uk/harry/mosflm/mosflm_user_guide.html#a3.

DENZO

Z is parallel to the incident radiation beam. X is parallel to the spindle axis, from the crystal to the goniometer base. Y is the so-called "vertical" axis is perpendicular to the spindle and beam axes.

In terms of crystal orientation rotations: rotz would again denote rotations of the crystal around the beam axis, rotx would denote rotations of the crystal about the spindle axis and roty would denote rotations about the axis perpendicular to the beam and the spindle.

XDS

In XDS, the crystal orientation matrix, the detector cooordinates and the goniosta system are defined relative to a laboratory coordinate frame. This definition makes it possible to descibe any possible experimental setup. The complete description of this coordinate system is available here: http://www.mpimf-heidelberg.mpg.de/~kabsch/xds/coordinate_systems.html.

However, in the distributed XDS input files, the most common orientation for the beam is along the Z axis.



Resuming Table




MOSFLM

DENZO

XDS


Beam along

X

Z

Z


Rotation axis along

Z

X

X if the rotation axis is horizontal (most common on synchrotron)
or
Y if the rotation axis is vertical


Third axis

Y = Z × X

Y = Z × X

Y = Z × X
or
X = Y × Z



Permutation matrices Q

[Q] are permutation matrices to go from one UB matrix to the other ([UBmos] = [Qdnz2mos] [UBdnz])


Qdnz2mos     =

0

0

1

Qmos2dnz     =

0

0

1

1

0

0

1

0

0

0

1

0

0

1

0

Qdnz2xds(1)    =

0

1

0

Qxds2dnz(1)     =

0

1

0

1

0

0

1

0

0

0

0

1

0

0

1

Qmos2xds(1)     =

0

0

1

Qxds2mos(1)     =

0

0

1

0

1

0

0

1

0

1

0

0

1

0

0

(1) In the case that  the rotation  axis is horizontal and perpendicular to the beam direction.



References

  1.  

  2.  

  3.  

  4.  

Appendix A.    File format for the orientation matrices

In all the data processing programs the crystal orientations matrices are written with a specific format  in an ASCII file. These format are described bellow.

MOSFLM

The REFIX format used by mosflm is the following:

Content
Description
Fortran Format
UB11 UB12 UB13

UB = setting matrix

3f12.7
UB21 UB22 UB23
3f12.7
UB31 UB32 UB33
3f12.7
dummy


3f12.7
Ur11 Ur12 Ur13

Ur = reference orientation matrix

3f12.7
Ur21 Ur22 Ur23
3f12.7
Ur31 Ur32 Ur33
3f12.7
cell

cell parameters

6f12.4
phixyzr

(mis)setting angles

3f12.4



Example:

 -0.02097959 -0.00902253  0.00277554
  0.01076026 -0.01447723 -0.00303052
  0.01271281 -0.00263528  0.00714553
       0.000       0.000       0.000
 -0.78320117 -0.52269857  0.33672263
  0.40169735 -0.83873395 -0.36764740
  0.47458947 -0.15268128  0.86686404
     36.5750     56.7600    118.8580     90.0000     90.0000     90.0000
       0.000       0.000       0.000

DENZO

The *.x file contains in the first lines the following informations:


XDS