: Beekman, Matthew [mailto:mbeek...@cas.usf.edu]
Sent: Saturday, March 07, 2009 7:20 PM
To: Peter Y. Zavalij; rietveld_l@ill.fr
Subject: RE: cRs
Hello all,
A quick question regarding the background subtracted R values:
In the .LST file, GSAS gives two sets of values for wRp and Rp: Fitted
AM
Subject: Re: cRs
As a rule, before doing that I'd switch to xye format to preserve the
statistics
Wow. What a rule.
Did anyone try to calculate simple mean deviance and compare with popular
R factors?
OS
Olga Smirnova wrote:
Did anyone try to calculate simple mean deviance and compare with
popular R factors?
OS
For simple mean deviance do you mean like in:
http://en.wikipedia.org/wiki/Deviance_(statistics)
Seems we normally call that chi^2. If that's what you meant, then yes,
people do
Subject: Re: cRs
Dear Olga!
Maybe you should explain what do you mean by saying background?
To my opinion you were given an exhaustive answer, but you still disagree
with companions.
This is puzzling.
I suppose that you are assigning as background contribution from partially
amorphous
:* Wednesday, March 04, 2009 8:17 AM
*To:* Jon Wright; olga.smirn...@hw7.ecs.kyoto-u.ac.jp
*Cc:* rietveld_l@ill.fr
*Subject:* RE: cRs
I'll put my tuppence worth in here as there can be another
consideration with high backgrounds.
Normally I wouldn't touch the background, but there are times when
, 2009 8:17 AM
*To:* Jon Wright; olga.smirn...@hw7.ecs.kyoto-u.ac.jp
*Cc:* rietveld_l@ill.fr
*Subject:* RE: cRs
I'll put my tuppence worth in here as there can be another
consideration with high backgrounds.
Normally I wouldn't touch the background, but there are times when a
high background
Maxim V. Lobanov wrote:
However, some Rietveld programs do not have good selection of BG functions,
and it is sometimes problematic to correctly fit the BG - so, I think in this
case
careful BG removal would be the only option.
Not the only option...
You have an option to forget about the
Dear Olga,
As you've noticed, the Rietveld R-factors tell you how well you fit the
pattern, but don't tell you how well you fit the peaks. There is a
correlated intensities R-factor which follows from the methods outlined in:
J. Appl. Cryst. (2004). 37, 621-628[
Dear All,
I think one should not just say that it is /verbotten /to subtract
background.
Merci to all replies. I would swallow and 'subtract' if I would not be full.
:-)
Best regards,
Olga
Olga Smirnova wrote:
Andreas Leineweber wrote:
Dear all,
I think one should not just say that it
[mailto:m_loba...@huntsman-nmg.com]
Sent: Tue 3/3/2009 11:35 PM
To: rietveld_l@ill.fr
Subject: RE: cRs
As far as I understand, the major issue is that BG subtraction changes the
error statistics (accordingly, weights applied in calculating function to
minimize...). It is also somewhat arbitrary how you
Rwp for the paper!
Pam
From: Jon Wright [mailto:wri...@esrf.fr]
Sent: Wed 04/03/2009 4:00 AM
To: olga.smirn...@hw7.ecs.kyoto-u.ac.jp
Cc: rietveld_l@ill.fr
Subject: Re: cRs
Dear Olga,
As you've noticed, the Rietveld R-factors tell you how well you fit
; olga.smirn...@hw7.ecs.kyoto-u.ac.jp
Cc: rietveld_l@ill.fr
Subject: RE: cRs
I'll put my tuppence worth in here as there can be another consideration
with high backgrounds.
Normally I wouldn't touch the background, but there are times when a high
background causes an artificially shallow minimum
Background removal is verbotten!
Brian O'Connor
From: Olga Smirnova [mailto:olga.smirn...@hw7.ecs.kyoto-u.ac.jp]
Sent: Wed 4/03/2009 2:14 PM
To: rietveld_l@ill.fr
Subject: cRs
Dear All,
How is life with conventional R factors when you always have to divide
by
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-Original Message-
From: Olga Smirnova [mailto:olga.smirn...@hw7.ecs.kyoto-u.ac.jp]
Sent: Wednesday, 4 March 2009 16:30
To: Brian O'Connor
Cc: rietveld_l@ill.fr
Subject: Re: cRs
According to my
: Wednesday, March 04, 2009 8:32 AM
To: olga.smirn...@hw7.ecs.kyoto-u.ac.jp
Cc: rietveld_l@ill.fr
Subject: RE: cRs
It's German... verboten == forbidden.
You should never delete the background from a diffraction pattern prior to
(Rietveld) analysis.
It changes peak positions and shapes
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