> 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
