Dear Maxim,
In the expression
Dv=3mu_4/2mu_3
mu is related to the crystal RADIUS distribution, but in
<L>v=3mu_4/4mu_3
mu is related to the crystal DIAMETER distribution
As for the instrumental and strain contributions, they may be correctly allowed
for along with the size effect using the TCH pV function from which you may get
estimations for VWDS and AWDS.
See, for instance, EXAMPLE3 in the DDM suite where the refinement of the Ceria
sample from the Size-Strain Round Robin is presented.
Best regards,
Leonid
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Leonid A. Solovyov
Institute of Chemistry and Chemical Technology
660049, K. Marx 42, Krasnoyarsk, Russia
www.icct.ru/eng/content/persons/Sol_LA
www.geocities.com/l_solovyov
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--- On Mon, 12/15/08, Максим В. Лобанов <m_loba...@huntsman-nmg.com> wrote:
> From: Максим В. Лобанов <m_loba...@huntsman-nmg.com>
> Subject: RE: calculation of VWDS and SWDS from distributions?
> To: "rietveld_l@ill.fr" <rietveld_l@ill.fr>
> Cc: "Eduard E. Levin" <le...@elch.chem.msu.ru>
> Date: Monday, December 15, 2008, 6:04 AM
> Dear colleagues,
>
> First of all, thanks to Dr. Ortiz for the
> advice/explanation.
>
> I would like to point out some discrepancy in the standard
> formulae for VWDS/SWDS, which are given in various
> well-respected articles.
>
> 1) N.C. Popa, D. Balzar, JAC 35, 338, formulae 7-8:
> Dv=3mu_4/2mu_3 (7)
> and
> Da=4mu_3/3mu_2 (8)
>
> 2) P. Scardi, M. Leoni, JAC 39, 24, formulae 1a-1b:
> <L>s=2mu_3/3mu_2 (1a)
> and
> <L>v=3mu_4/4mu_3 (1b)
>
> It seems that these definitions are differing merely by a
> factor of two.
> I am curious if anybody could clarify this point.
>
> Sincerely,
> Maxim.
>
