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 is /verbotten /to "subtract"
background. This Verbot should only apply for simple Rietveld
refinement without considering the effect of the subtraction in the
counting statistics (said before) and not telling it in the
publication. But in some case something like background subtraction
may be helpful. At least I recall an older work where it was proposed
that it may be reasonable to calculate a special R-value considering
the background level:
Author(s): JANSEN E
<http://apps.isiknowledge.com/DaisyOneClickSearch.do?product=WOS&search_mode=DaisyOneClickSearch&db_id=&SID=T2jpIF91p18847FCOP@&name=JANSEN%20E&ut=A1994PB26500006&pos=1>,
SCHAFER W
<http://apps.isiknowledge.com/DaisyOneClickSearch.do?product=WOS&search_mode=DaisyOneClickSearch&db_id=&SID=T2jpIF91p18847FCOP@&name=SCHAFER%20W&ut=A1994PB26500006&pos=2>,
WILL G
<http://apps.isiknowledge.com/DaisyOneClickSearch.do?product=WOS&search_mode=DaisyOneClickSearch&db_id=&SID=T2jpIF91p18847FCOP@&name=WILL%20G&ut=A1994PB26500006&pos=3>
Source: JOURNAL OF APPLIED CRYSTALLOGRAPHY Volume: 27 Pages:
492-496 Part: Part 4 Published: AUG 1 1994 Times Cited: 19
<http://apps.isiknowledge.com/CitingArticles.do?product=WOS&search_mode=CitingArticles&SID=T2jpIF91p18847FCOP@&db_id=WOS&parentQid=1&parentDoc=15&recid=88169708>
References: 21
<http://apps.isiknowledge.com/CitedRefList.do?product=WOS&search_mode=CitedRefList&SID=T2jpIF91p18847FCOP@&db_id=WOS&parentQid=1&parentDoc=15&recid=88169708>
Citation Map*Citation Map* <javascript:void();> beta Abstract:
Profile and Bragg R values are discussed with respect to different
versions of the Rietveld program. The R values calculated from an
exemplary neutron diffraction pattern are compared. Results obtained
by a modified treatment of background and by a simplified method to
decompose an observed pattern into Bragg intensities are presented.
However, I do not have never applied that method and I do not know
whether it can be regarded as commonly accepted. At least I don't
think that it has been included in any of the present-day major
Rietveld programs.
Best regards
Andreas Leineweber
Olga Smirnova wrote:
Dear All,
How is life with conventional R factors when you always have to
divide by zero background?
Let's have time. Considering a part of the profile without peaks one
gets 100% cR.
I did not give the agreement factor; I would say those cR with all
non-excluded points is incorrect, but cR for
points with Bragg contribution is almost the same!
Do you decrease the Rs by adding the background or do you increase
cRs by subtracting the background?
OS
PS I did not ask my supervisor before sending such a mail.
