indications for the twin operation) indicate a best rotation about the direction in (). Negative
Freq numbers indicate a best rotation about the vector in [].
The program needs an '.fcf' file (e.g. shelxl.fcf) [or a .cif + .fcf] for the analysis.
Cases of merohedral twinning are normally handled in a subsequent BASF/TWIN
refinement.
Alternatively, an HKLF 5 type of file for the best solution is written to a file with extension
'.hkp' to be used for subsequent SHELXL refinement.
Options are provided to display the twinning effect in reciprocal space.
Parameters:
Iobs-Icalc/sigma Crit: PAR(413) = 10.0
Theta Criterium: PAR(414) = 0.05
Indexfit criterium: PAR(415) = 0.1
The analysis can be invoked in various ways. (The -T option bypasses the alternative
invocation from the PLATON menu).
1.
Given an '.fcf' run
platon -T compound.fcf
2.
Given an .cif & .fcf run
platon -T compound.cif
In this case, the missing calculated structure factors will be calculated prior to the
analysis for twinning.
Example:
s103b.fcf
. Monoclinic, twinned about (1 0 0). Overlap in 0, 6 & 12 th l-layer.
PLATON Analysis Result:
2-Rotation about ( 1 0 0 )
Rotation Matrix:
1 0 0.8347
0 -1 0
0 0 -1
An HKLF 5 type SHELXL file is written. In order to proceed with the SHELXL refinement:
1.
save the original
.hkl file
2.
1copy file
.hkp to
.hkl
3.
copy latest
.res to
.ins
4. add 'BASF 0.0' to the '.ins' instruction set.
5. change 'HKLF' line into 'HKLF 5' (no transformation matrix !
1.3.5.1 - MULABS - Blessing's Method for Absorption Correction
MULABS implements a semi-empirical method for absorption correction using multiple
scanned reflections (i.e. multiple symmetry, azimuth equivalent reflection data, CCD-
detector datasets) following the excellent algorithm published by Bob Blessing, (Blessing,
1995) (and also available in his SORTAV program).
Related Keyboard Instruction:
MULABS (mu radius (tmin tmax l0max l1max)) (NOCHECK)