Dear Mario,
One more possible problem of applying preferred orientation corrections in QPA
is that not all of them are normalized. For example, the March-Dollase
correction is normalized and can be applied safely, but the Rietveld-Toraya
correction is inapplicable to QPA as it does not preserve the scale
normalization.
Best regards,
Leonid
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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
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--- On Mon, 10/27/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> From: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> Subject: Quantitative analysis
> To: Rietveld_l@ill.fr
> Date: Monday, October 27, 2008, 3:48 PM
> Dear all,
>
> I have this question,
>
> I have been refined one mixture (of well-know percentage
> composition) of
> CaCO3, CaF2, SiO2 and Al2O3, with preferential orientation
> in CaCO3 (104)
> and CaF2 (111) with good results. When I add to the mixture
> FeCO3 and I
> refine with preferential orientation (104), it happens that
> when I don´t
> apply the preferential orientation in all this phases, I
> have correct
> values of percentage composition, but when I apply the
> preferential
> orientation the refinement is good but with incorrect
> values of percentage
> composition. This experiment has been taken in Bragg
> Brentano geometry.
> How I should refine this mixture?
>
> Thanks a lot by your help.
>
> Mario Macías
> Universidad Industrial de Santander
> Colombia
