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Hi Clemens,<br>
<br>
In the current public release of RMCProfile, it seems that we do
have some problems with the normalization for X-ray data due to the
q-dependent form factors. Therefore the normalization may not be so
straightforward as it is for neutron. Actually, if you have a look
at the manual in the section introducing the 'XRAY_REAL_SPACE_DATA'
keyword, you may probably notice that we have different options for
the normalization.<br>
<br>
I have ever looked at your attached pictures showing the problem you
described, but since the mailing list gets rid of the attachment so
I cannot see it now. So can I ask you to share with me (email:
<a class="moz-txt-link-abbreviated" href="mailto:zhangy3@ornl.gov">zhangy3@ornl.gov</a>) your previously attached pictures? Also could you
please share with the whole folder in which you ran the RMCProfile
so I can have a look and see whether I can help solving the problem?
Thank you!<br>
<br>
Meanwhile, we are currently working on a new way for the X-ray data
fitting in RMCProfile, and in the new version we do the Fourier
transform internally in RMCProfile so we don't need to provide the
real space data by ourselves. The only thing we need is to provide
the reciprocal space data and give the program a keyword saying we
also want to fit in real space. The program now is not available to
public yet, but if you want to have a try, I can send the package to
you (if you tell me which operating system you are using).<br>
<br>
Cheers,<br>
Yuanpeng<br>
<br>
<div class="moz-signature">
<br>
<b>Dr. Yuanpeng Zhang</b><br>
Postdoctoral Research Associate<br>
Chemical and Engineering Materials Division<br>
Neutron Science Directorate<br>
<br>
Oak Ridge National Laboratory<br>
1 Bethel Valley Road<br>
Bldg. 8600, Room C-509-C, Mailstop 6454<br>
Oak Ridge, TN 37831-6475<br>
Mobile | 865-335-4818<br>
Email | <a href="mailto:zhangy3@ornl.gov" target="_top">zhangy3@ornl.gov</a>
| Web | <a href="http://aipeng1990.life">aipeng1990.life</a></div>
<div class="moz-cite-prefix">On 05/15/2018 08:30 AM, Clemens
Prescher wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAFcD9XkBD27m91wYe882+pwpP0UQCgM0XzDgdnuwP=-UbiYQ7g@mail.gmail.com">
<pre wrap="">Hi there,
i have problems figuring out how X-ray derived PDF should be correctly
inputted into RMCProfile.
On page 157 in the RMCProfile manual it is written that the X-ray G(r)
needs to be normalised so that it is scaled from 0 to 1. This is exactly
the format i have. However, if I init my calculation and plot the "PDFs of
rmc fit" using rmcplot it has an offset (please see the attached figure "
gr_without_offset.ps")
It is clear, that the RMC fit is actually normalized to 0 when going into
infinity.
I thought, this might just a result by subtracting 1 from the previously 0
to 1 normalized G(r). But after several iterations using an offset of -1 it
became clear that low part is not normlized to -1. (see the
"gr_with_offset" figure attached).
In the manual it is also written that G(r) goes from -(sum c_j b_j)² to 0.
But for X-ray this does not make sense due to q-dependent form factors...
Can you please explain me how i should transform my data?
Best wishes,
Clemens
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</pre>
</blockquote>
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