CHEKCELL: Graphical Powder Indexing helper and Spacegroup Assignment Software that links into the Crysfire Powder Indexing Suite by Robin Shirley
CHEKCELL can be obtained off the web at the the LMGP
(Laboratoire des Materiaux et du Génie Physique de l'Ecole Supérieure de
Physique de Grenoble http://www.inpg.fr/LMGP/)
program suite site at:
The example data file is of Armel Le Bail's laboratory Powder X-ray Diffraction data of Tetracycline Hydrochloride (supplied with the Chekcell distribution) using Indexing results from the Crysfire Powder Indexing Suite by Robin Shirley.
This runthrough will show the new December 2001 Chekcell Chekcell Density / Z explorer. The Molecular Formula of Tetracycline Hydrochloride is C22 H25 N2 O8 Cl1.
There is also a Density Explorer in the Truecell and LePage dialog options for when you generate derivative cells.
Opening up the data (diffraction data, peak listing and Crysfire summary file)
The DENSITY Icon located as part of the middle set of Icons (on the right).
Clicking on the Density Icon leads to the Density Menu.
If you have saved previous molecular formula information, you can retrieve this using the File, Import Formula menu; or just type in the molecular formular information, density range and Z range. (then you may like to save this safely into a file using the File, Export Formula menu)
Input the Molecular Formula, Density Range, and Z range
of interest. (this can be changed as required)
The molecular weight will be calculated, as well as the estimated volume of the molecule - based on 18 cubic Angstrom per non-hydrogen atom. This can also be changed by the user.
Now select whether you wish to calc on Density or
Z range and click on the Calc button to see
the output which gives a list of Z, density, total estimated atomic volume,
and the ratio of "total estimated atomic volume"/"trial Cell volume".
To obtain an ASCII file of the output, use the Edit/Print button.
Play and have fun. Don't forget that there is a Density Explorer in the Truecell and LePage dialog options.