Kavecansky
Viktor Kavecansky RNDr.CSc. ( (no email) )
Mon, 19 Sep 1994 16:05:12 +0200
On Sep 19., Mark Raven wrote:
> ...
> My question is, has anyone made an effort to modify the March preferred
> orientation correction in the Rietveld code to allow for multiple preferred
> orientation directions?
> ...
>
well, I tried to extend the March preferred orientation correction in the
Rietveld code but only for the case of two various preferred orientation
directions. Three parameters are to be refined : two March r-parameters for
the two kinds of preferred orientations and the third parameter which
represents the volume fraction of crystallites dominated by one of them
[W.A.Dollase in J.Appl.Cryst.,19, (1986), p.267].
The procedure was used to refine the structure of the high temperature
superconductors Y-Ba-Cu-O prepared in the form of pressed pellets. The
resulting Rwp factors were found to be a little smaller then in the case
of using standard Rietveld code but the relatively strong correlations
between the three parameters considerably complicated the refinement.
kavecansky
-- Viktor Kavecansky Institute of Experimental Physics SAS 47 Watson Str., 043 53 Kosice, Slovakia phone:(+42 95) 381 15 /136 fax:(+45 95) 363 20 telex: 77348 sav c