> I have a related question about the so-called Kalpha3.
> Trying to take account of it, I only obtain some slight increase
> in the Rp and Rwp, though the fit seems to have improved,
> at first glance.
>
> Has someone a powder pattern available which shows clearly
> Kalpha3, and which he was able to fit by a Rietveld code
> (which one ?) and obtained some improvement in the Rp
> and Rwp values ?
Yes, in the fundamental parameters Koalariet/XFIT software
on the Y2O3 standard pattern given with the program.
http://www.ccp14.ac.uk/tutorial/xfit-95/getxfit.htm
The improvement was done by fitting to Kalpha5.
The data was collected on a Philips 1050 style diffractometer.
For good crystalline material, you do see an improvement.
I didn't bother going from Kalpha2 to Kalpha3 as Koalariet
can easily do the Kalpha5.
Kalpha2 Rwp = 6.908
Kalpha5 Rwp = 5.455
By doing peak profiling using XFIT with Kalpha5 you get
a noticable improvement over Kalpha2.
----
I assume BGMN (another fundamental parameters Rietveld) and
XND (which can handle this type of thing as well using its
wavelength definitions/parasitic lines option) would see
similar improvements.
BGMN
http://www.bgmn.de/
http://www.ccp14.ac.uk/ccp/web-mirrors/bgmn/
XND
ftp://old-labs.polycnrs-gre.fr/pub/xnd/
http://www.ccp14.ac.uk/ccp/ccp14/ftp-mirror/xnd/pub/xnd/
----
Are there any other Rietvelds out there that can
handle custom multiple wavelength definitions such
as 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
