Endeavour: Frequently Asked Questions
The "Frequently Asked Questions" (FAQ) page for Endeavour provides an overview over the most common questions along with the corresponding answers.
If you encounter a problem with your installation, please check if your
Endeavour version is up-to-date. You find an update opportunity
on our Endeavour Update Page.
Since many functions of Endeavour, mainly the crystal structure visualization, are related with functions in Diamond, please
also read the Frequently Asked Questions page for Diamond.
You can also send your comment or request to
support@crystalimpact.com.
Q(uestion): I want to determine the unit cell parameters from the powder
diffraction pattern (indexing), but Endeavour can't do it.
A(nswer): One option is to use Match! along
with the FullProf package (which also contains
the indexing programs Treor and Dicvol). This is demonstrated in the corresponding
tutorial video.
An alternative would be to use the Crysfire powder indexing system
that can be downloaded free-of-charge (for academic usage) from
http://www.ccp14.ac.uk/tutorial/crys/.
Crysfire still is an excellent and elaborate package for indexing, being able
to use a large variety of different indexing programs/methods (ITO, TREOR, DICVOL,
KOHL etc.). Having a variety of different indexing approaches available is generally
adventageous, since not all methods are equally successful in solving different
indexing problems.
Q: How can I define the total count of atoms per unit cell (cf.
"Preparation of Structure Solution" wizard) - my XRD software can't find it.
A: The way to find a reasonable number of atoms per unit cell strongly
depends on the compound under investigation. In any case, the composition (formula
sum) of the compound under investigation must be known first. Typically, one can
then use the density (either of the compound under investigation or the one of similar
compounds) and/or the space filling as a guide:
First, you should try to find a reasonable density and/or space filling percentage,
e.g. by measurement and/or determining values from similar compounds/structures.
Afterwards, you should compare these value(s) to the ones that are calculated
and displayed for the current input data in step 2 and 3 of Endeavour's so-called
"structure solution wizard". Provided that the composition (formula sum) has already
been entered, you can adjust the "Z" parameter (Z = number of formula
units per unit cell) in order to find the best agreement between estimated and calculated
density/space filling.
In some cases, it may also be helpful to take the multiplicity of the general position
of the space group into account, in order to find a reasonable value for Z.
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