Dear Maxim,
Gaussian peak shape is, normally, related to the instrumental, strain and/or
lattice distribution broadening. The Williamson-Hall plot shows the dependency
of broadening on the diffraction angle and if this dependency can not be
explained by strain then it is most probably instrumental. If you use the
Bragg-Brentano geometry a possible reason might be a loose powder, sample
misalignment or surface roughness.
Regards,
Leonid
*******************************************************
Leonid A. Solovyov
Institute of Chemistry and Chemical Technology K. Marx av., 42
660049, Krasnoyarsk Russia
Phone: +7 3912 495663
Fax: +7 3912 238658
www.icct.ru/eng/content/persons/Sol_LA
*******************************************************
--- On Tue, 10/21/08, Maxim V. Lobanov <[EMAIL PROTECTED]> wrote:
> From: Maxim V. Lobanov <[EMAIL PROTECTED]>
> Subject: question on size-strain analysis
> To: rietveld_l@ill.fr
> Cc: "Дмитрий А. Павлов" <[EMAIL PROTECTED]>
> Date: Tuesday, October 21, 2008, 7:20 AM
> Dear colleagues,
>
> I have a probably very basic question related to
> size-strain analysis:
>
> we have a pattern of a nanocrystalline oxide, which shows
> (from
> Williamson-Hall plot) almost purely size broadening, and
> shape of
> reflections is to good accuracy Gaussian.
> I am curious what type of microstructure this Gaussian
> behavior can reflect.
> Maybe it is just something usual, but so far I had only
> observed
> predominantly Lorentzian broadening in similar materials...
>
> Sincerely,
> Maxim.
>
>
> -------------------------------------------
> Dr. Maxim Lobanov
> R&D Director
> Huntsman-NMG
> mailto: [EMAIL PROTECTED]
>
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