[sdpd] Chekcell GUI Powder Indexing Helper Program for cell and spacegroup assignment by Jean Langier and Bernard Bochu.

[L.M.D.Cranswick...@dl.ac.uk]

CHEKCELL: Graphically determining most likely cells and spacegroups
from powder diffraction data.

(Note: Chekcell should still be considered a beta test version that
is still under development.  Please contact the authors at
jean.laugier2...@wanadoo.fr if you have any problems or feature requests.
Also please check for updates regularly at:
  http://www.ccp14.ac.uk/tutorial/lmgp/).

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A new program from the LMGP suite for Windows
by Jean Laugier and Bernard Bochu is the CHEKCELL
program for helping in graphically identifying possible
cells from powder indexing (automatic and manual point and click mode) and
assigning spacegroups (again via automatic and manual point and click mode).
The program is based on the design of the "celref" unit cell refinement
software but optimised for easy graphical powder indexing.

Using the combination of Crysfire (or any list of trial cells in the
Crysfire *.SUM format) and Chekcell, Powder Indexing is no longer
the drudgery it often is and becomes easier and less stressful.
Especially when attempting the indexing of marginal data of poor
resolution and/or large cells and/or possible spurious peaks.

----

Chekcell reads a Crysfire powder indexing suite *.SUM summary file
and can graphically help assign the "most likely spacegroups" for
a particular cell by manual and automatic methods using the
"Best Group" option.

Using the automatic "BEST SOLUTION" option:
Chekcell can easily browse the suggested trial cells generated by
the programs within Crysfire (from the *.SUM summary file).
The user has control over:
  - size of tested cells,
  - figure of merit,
  - number of peaks indexed,
  - avoiding repeat determinations of duplicate cells,
  - cell type that is automatically trialed for likely spacegroups.

e.g., The various Crysfire programs give you a summary file with
1 to a few thousand different trial cells.  Using the "BEST SOLUTION"
option, Chekcell will automatically dredge through this mass of
results and present the most likely cell/spacegroup combinations.
Then allowing the user to manually check out these results and
other guesses via a point and click Windows interface.

It is still up to the user to interact with the powder indexing
process in an intelligent manner; but CELREF takes most of the
time-consuming drudge work.

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Tutorials and examples on using this program are available on the web:

Automatically obtaining "Best (Space)Group" of a manually selected cell:
  http://www.ccp14.ac.uk/tutorial/lmgp/chekcell.htm
  http://www.ccp14.ac.uk/tutorial/lmgp/chekcellb.htm
  http://www.ccp14.ac.uk/tutorial/lmgp/chekcellc.htm
  http://www.ccp14.ac.uk/tutorial/lmgp/chekcelld.htm

Automatically obtaining the "BEST (cell/spacegroup) SOLUTION"
from a list of trial cells:
  http://www.ccp14.ac.uk/tutorial/lmgp/achekcell.htm
  http://www.ccp14.ac.uk/tutorial/lmgp/achekcellb.htm
  http://www.ccp14.ac.uk/tutorial/lmgp/achekcellc.htm
  http://www.ccp14.ac.uk/tutorial/lmgp/achekcelld.htm

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Chekcell can be obtained via download from the CCP14 Site and it's
mirrors:

  http://www.ccp14.ac.uk/ccp/web-mirrors/lmgp-laugier-bochu/chekcell.zip
  http://ccp14.sims.nrc.ca/ccp/web-mirrors/lmgp-laugier-bochu/chekcell.zip
  ftp://ftp.minerals.csiro.au/pub/xtallography/ccp14/ccp/web-mirrors/lmgp-laugier-bochu/chekcell.zip

(Crysfire Indexing Suite (with ito, treor, dicvol, taup, fjzn, kohl,
losh and lzon) by Robin Shirley is freely available off the
CCP14 web site - including tutorials on its use)

Tutorials:
     http://www.ccp14.ac.uk/tutorial/crys/
Download:
  http://www.ccp14.ac.uk/ccp/web-mirrors/crys-r-shirley/
  http://ccp14.sims.nrc.ca/ccp/web-mirrors/crys-r-shirley/
  ftp://ftp.minerals.csiro.au/pub/xtallography/ccp14/ccp/web-mirrors/crys-r-shirley/

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Regards,

Lachlan.

-- 
Lachlan M. D. Cranswick

Collaborative Computational Project No 14 (CCP14)
    for Single Crystal and Powder Diffraction
Daresbury Laboratory, Warrington, WA4 4AD U.K
Tel: +44-1925-603703  Fax: +44-1925-603124
E-mail: l.cranswick...@dl.ac.uk  Ext: 3703  Room C14
                           http://www.ccp14.ac.uk