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 [EMAIL PROTECTED] if you have any problems or feature requests. Also please check for updates regularly at: http://www.ccp14.ac.uk/tutorial/lmgp/). --- 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 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. ------ 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 ---------- 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/ --------- 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: [EMAIL PROTECTED] Ext: 3703 Room C14 http://www.ccp14.ac.uk
