RIET: Re: I am a newcome, how can I begin my rietveld refinement analysis

2008-11-30 Thread Lachlan Cranswick

Moderate self citation alert follows - the practical notes from the 
Canadian Powder Diffraction Workshop give starting practical on
fitting using GSAS which might help guide starting refinements
if you following the manual examples.

  http://www.cins.ca/cpdw/notes.html

Lachlan.


At 08:11 AM 11/30/2008 +0800, Mingtao Li wrote:
Hi, everyone,
  I am a newcome to Rietveld refinement. Actually I am a student
majored in photocatalytic splitting water for hydrogen production. We
want to analysis the structures of our photocatalysts via rietveld
method. For that purpose we got a X'pert Pro diffractionmeter from
Panalytica about 3 years ago. But rietveld is too difficult to start.
Now I have read some books and downloaded some programs from ccp14
such as fullprof, checkcell and so on. Also I have tested some
examples. However I am still confused. How can I determine the initial
value of some parameters such as U, V and W. Maybe I need a
Instrumental Resolution Function file, but how can set that file?

Can anybody give me some advice about this?

thanks a million.

-- 
Mingtao Li
State Key Laboratory of Multiphase Flow in Power Engineering
School of Energy and Power Engineering
Xi'an Jiaotong University
Xi'an, 710049
P.R.China
Tel: +86-29-8266 8296
Fax: +86-29-8266 9033
Email: [EMAIL PROTECTED]



---
Lachlan M. D. Cranswick
Contact outside working hours /
  Coordonnees en dehors des heures de travail:
NEW E-mail / courriel:  lachlanc *at* magma.ca
Home Tel: (613) 584-4226 ; Cell/mobile: (613) 401-6254
WWW: http://lachlan.bluehaze.com.au/
P.O. Box 2057, Deep River, Ontario, Canada, K0J 1P0

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I am a newcome, how can I begin my rietveld refinement analysis

2008-11-29 Thread Mingtao Li
Hi, everyone,
 I am a newcome to Rietveld refinement. Actually I am a student
majored in photocatalytic splitting water for hydrogen production. We
want to analysis the structures of our photocatalysts via rietveld
method. For that purpose we got a X'pert Pro diffractionmeter from
Panalytica about 3 years ago. But rietveld is too difficult to start.
Now I have read some books and downloaded some programs from ccp14
such as fullprof, checkcell and so on. Also I have tested some
examples. However I am still confused. How can I determine the initial
value of some parameters such as U, V and W. Maybe I need a
Instrumental Resolution Function file, but how can set that file?

Can anybody give me some advice about this?

thanks a million.

-- 
Mingtao Li
State Key Laboratory of Multiphase Flow in Power Engineering
School of Energy and Power Engineering
Xi'an Jiaotong University
Xi'an, 710049
P.R.China
Tel: +86-29-8266 8296
Fax: +86-29-8266 9033
Email: [EMAIL PROTECTED]


Re: I am a newcome, how can I begin my rietveld refinement analysis

2008-11-29 Thread Leonid Solovyov




At the
initial stage you don’t need precise values of U, V, and W. You may set U=0,
V=0, and W equal to the squared FWHM of the highest peak.

 



Leonid


*
 
Leonid A. Solovyov
 
Institute of Chemistry and Chemical Technology
 
660049, K. Marx 42, Krasnoyarsk, Russia
 
www.icct.ru/eng/content/persons/Sol_LA

  www.geocities.com/l_solovyov

*
--- On Sun, 11/30/08, Mingtao Li [EMAIL PROTECTED] wrote:

Hi, everyone,
 I am a newcome to Rietveld refinement. Actually I am a student
majored in photocatalytic splitting water for hydrogen production. We
want to analysis the structures of our photocatalysts via rietveld
method. For that purpose we got a X'pert Pro diffractionmeter from
Panalytica about 3 years ago. But rietveld is too difficult to start.
Now I have read some books and downloaded some programs from ccp14
such as fullprof, checkcell and so on. Also I have tested some
examples. However I am still confused. How can I determine the initial
value of some parameters such as U, V and W. Maybe I need a
Instrumental Resolution Function file, but how can set that file?

Can anybody give me some advice about this?

thanks a million.

-- 
Mingtao Li
State Key Laboratory of Multiphase Flow in Power Engineering
School of Energy and Power Engineering
Xi'an Jiaotong University
Xi'an, 710049
P.R.China
Tel: +86-29-8266 8296
Fax: +86-29-8266 9033
Email: [EMAIL PROTECTED]