Dear Lachlan and others,
I pretty sure this is not a problem with space group settings, bacause:
a) I have descripbed the structure in various space groups in both GSAS and
DBWS/Fullprof and the difference is always the same
b) the problem is in one single peak only
c) I have imported the GSAS .EXP-file into Cerius2 to draw the structure,
and it appears just as I intended it to.
Regards
Magnus
At 11:53 05.01.01 +0000, you wrote:
>
>> Doing Rietveld refinement with GSAS, I get close to zero calculated
>> intensity in the 110 peak. The rest of the pattern fits nicely. I have
>> tried to set POLA to diffent values between 0 and 1 (usually I lock it at
>> 0.98), and I have also tried the three possible settings of IPOL. None of
>> this has any significant influence on the calculated intensity of 110.
>>
>> If I insert my refined structure model into DBWS, I immediately get
>> sensible intensity in 110. The same happened when a colleague tried it in
>> Fullprof. The calculated structure factor for the peak is similar in GSAS
>> and DBWS.
>>
>> Does anybody have a idea of what I can be doing wrong? Or can it be a
>> problem with GSAS? I'm currently using the Linux version, but I have also
>> tried older UNIX versions.
>
>The main occassions I have encountered this type of behaviour
>(besides errors in structure input) is when different
>default settings of the spacegroup are assumed by different
>Rietveld programs.
>Might this mean the structure has to be transformed into a
>different spacegroup setting for which GSAS is the default?
>
>Inserting the cubic silicon metal co-ordinates directly
>from the ICSD can cause initial mayhem with various
>Rietvelds due to this.
>
>Lachlan.
>
>
>--
>Lachlan M. D. Cranswick
>
>Collaborative Computational Project No 14 (CCP14)
> for Single Crystal and Powder Diffraction
>Daresbury Laboratory, Warrington, WA4 4AD U.K
>Tel: +44-1925-603703 Fax: +44-1925-603124
>E-mail: [EMAIL PROTECTED] Ext: 3703 Room C14
> http://www.ccp14.ac.uk
>
>
>
