HKL Transformation and SHELX Direction Cosines

Transformation of Reflection Data

It is generally better not to touch the original SHELX reflection file with a transformation matrix, thus avoiding unnecessary chaos.
SHELX avoids that need with a useful facilily to specify a transformation matrix on the HKLF line to transform reflection data as provided to the 'CELL-standard'.
However, there are cases when a 'hard' transformation is needed.
PLATON provides a tool (the HKLT option) for such a transformation.

The following example illustrates the procedure:

Two files are needed:

compound.hkl : the reflection file (SHELX HKLF 4 - STYLE)
compound.ins : instruction file

Example: transformation from P21/c to P21/n : (1 0 1/0 1 0/ -1 0 0)

Two equivalent sets of instructions accomplish the transformation.

Using transformation matrix TRMX

 
  TRMX 1 0 1 0 1 0 -1 0 0
  CELL 0.71073 10.6597 9.1517 21.8466 90.0 102.25 90.0
  SPGR P21/c
  HKLF 4 1 1 0 0 0 1 0 0 0 1 
  HKLT

Using transformation matrix on HKLF line

  TITL N1848A
  CELL 0.71073 22.1829 9.1517 10.6593 90.0 105.76 90.0
  SPGR P21/n
  HKLF 4 1   1 0 1 0 1 0 -1 0 0
  HKLT

The specification of the space group is optional.

The example run (#2) would produce a new file compound.hkp
and a short VDU output when run as 'platon compound.ins :

:: TITL  N1848A                                                               
:: CELL    22.1829    9.1517   10.6597    90.000   105.758    90.000    2082.7
:: SPGR P21/n       

Direct Cell axes and HKL Transformation Matrix

    1.0000    0.0000    1.0000
    0.0000    1.0000    0.0000
   -1.0000    0.0000    0.0000

Coordinate Transformation Matrix

    0.0000    0.0000    1.0000
    0.0000    1.0000    0.0000
   -1.0000    0.0000    1.0000

Transformation Matrix for SHELX Direction Cosines

    0.0000    0.0000    1.0000
    0.0000    1.0000    0.0000
   -0.9848    0.0000    0.4805
:: HKLTRANS hkl on :hklt.hkp

MISC. TOOLS

PLATON HOMEPAGE

07-apr-1999 A.L.Spek