CELREF 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
CELREF: Graphical Unit Cell refinement.
The 4th of June 2002 version of Celref has a new option for manually defining HKLs and observed peak positions. This can be useful for difficult unit cell refinement involving distorted cells and high-angle overlapping reflections.
The following assumes you have a list of peak positions and HKLs which have been manually assigned to them.
Run Celref and load the raw diffraction data file (this is optional but allows graphical feedback with respect to the raw diffraction data)
Click on the Initial cell parameters tab and input the starting cell and spacegroup.
Now select the Selection of reflections tab and the Edit/Modif Icon.
This will bring up the Edit/ Modif selected reflections dialogue box.
Now start adding the HKLs and peak positions - inserting them into the Celref list by use of the Add/Modif Icon. Celref will automatically calculate the theoretical position once you have inputted the HKL and put your mouse cursor in the 2-theta obs box.
The peak and matching HKL will also be displayed as blue lines over the raw diffraction data.
You can then use the Save selection icon to save and backup the list then continue on with the refinement. (to reload this list, go into the measured reflections tab and the lst file is one of the file types that can be loaded. In Selection of reflections, the Re-ind from list Icon will then reapply the relevant HKLs to the peaks.)
Now just go into the Cell Refinement tab and continue with the refinement as per normal.