>Now my problem as a synthetic inorganic chemist is most often this: I do
>have patterns of rather poor quality (only 1-2 sec integration time per
>step) thus the signal-to-noise-ratio is most often not suitable for a
>Rietveld-refinement (10-20; unless I do have very well crystallized
>samples).
>In fact, for 90% of my XRD patterns, it would be sufficient to determine
>the lattice constants (and space group) directly from the routine xrd
>patterns.
>
>Do you think, the methods are developped enough to treat this noisy stuff?
>Would be much easier for me ;-).
You did not mention if you know your sample structure. If the structure
is known and your sample is just ill crystallized, you may attempt
cell parameters refinement. But if your compound structure is
hitherto unknown, OK, you may propose an indexation
to ICDD that will probably accept it. However I would not give
my hand to cut on its accuracy ! And you ?
>PS: I forgot to mention the usual range of my routine patterns: 5-80 °2Q.
>Usually, I will find about 40-60 reflections within this range.
Either trivial or half amorphous... In the past I refined glassy SiO2
by the Rietveld method but I never tried to refine the cell parameters
if you see my point :-).
Anyway, best wishes !
Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen, 72085 Le Mans cedex 9, France
http://fluo.univ-lemans.fr:8001/
http://www.cybercable.tm.fr/~cristal/welcome.html