Dear Claudia, Qingying Jia, Matt
Thank you so much for your responses :)
The shift in bond length I see is almost around 0.1-0.12 Angstrom, which is
not small enough to ignore. I think the coordination might be changing, if
not the oxidation state. I will redo the Artemis calculations with N as a
variable again to see if that helps. Because keeping my N constant actually
gave me pretty low Debye-Waller values and R factor was also below 5% so I
was assuming the fits were reliable.
I was also thinking maybe Mn is undergoing partial oxidation, however, in
bulk we do not see that change in the main XANES absorption peak. I am not
sure if that can be a possibility.
Thanks a lot again!
Kind Regards
Disha
Disha Gupta
Graduate Student
School of Materials Science and Engineering
Nanyang Technological University (NTU), Singapore
+65 84087404
DISHA001@e.ntu.edu.sg
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than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: Demeter on Windows 10 does not work (sikolen)
2. Re: No shift in XANES absorption peak (Claudia Schnohr)
3. Re: No shift in XANES absorption peak (Qingying Jia)
4. Re: Demeter on Windows 10 does not work (Matt Newville)
5. Re: No shift in XANES absorption peak (Matt Newville) ---------------------------------------------------------------------- Message: 1
Date: Mon, 11 Jun 2018 13:39:03 +0200
From: sikolen Thanks Kathy, It seems the problem is really with the wrong path... Now I see how to
fix it. Vadim On 2018-06-08 17:07, Kathy Dardenne wrote: Dear Vadim, I am running myself Demeter 0.9.26, 64bit under win10 and do not have
such
trouble. But your description is similar to the problem occurring with
the
previous release of Demeter 0.9.26 pre2 (old path for gnuplot
executable in
ini file leading the same effect), did you download the actual version
for
Demeter 0.9.26? this later trouble is fixed and Demeter runs smoothly
with
win7 and win10. Kathy -----Message d'origine-----
De?: Ifeffit Dear all, I've just changed my loving Windows-7 to the new Windows-10. I've
installed
Demeter (v.0.9.26, 64-bit), but it does not work: cmd-Windows appears
for
the a couple of seconds and disappears forever. Is it already known
problem
of the OS? Sorry, may be this question already appeared here, I just
missed
it. Vadim
--
***********************************
Dr. Vadim Sikolenko
Senior Scientist
Frank Laboratory of Neutron Physics
Vadim.Sikolenko@jinr.ru
Skype: svadimm
**********************************
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Vadim.Sikolenko@jinr.ru
Skype: svadimm
********************************** ------------------------------ Message: 2
Date: Mon, 11 Jun 2018 14:56:22 +0200
From: Claudia Schnohr Dear Disha, In principle, yes, there can be a change of bond length without a
notable change of the XANES. But it also depends on how large the bond
length changes are that you observe. I have studied a lot of semiconductor alloys, for example (In,Ga)P or
Cu(In,Ga)Se2 where the Ga and In atoms share the same lattice site.
They are always coordinated to four P or Se atoms, respectively, but
the bond lengths change by 0.02 to 0.03 A because the size of the unit
cell changes with In/Ga ratio. At the same time, the Ga and In XANES
is completely unaffected by a change of the In/Ga ratio. If you are
interested in this, you may have a look at Phys. Rev. B 85, 245204
(2012), J. Appl. Phys. 116, 093703 (2014), or Appl. Phys. Rev. 2,
031304 (2015). This is just to say that, yes, in some special cases you can have a
change of bond length without a change of XANES. There can be lot's of
other things going on, too :) Cheers, Claudia ----- Nachricht von Disha Gupta Betreff: Re: [Ifeffit] No shift in XANES absorption peak
An: ifeffit@millenia.cars.aps.anl.gov Dear Dr Carlo The edges are almost identical. The pre-edge intensity change isn't that
significant I feel. I did the Artemis fittings with the coordination
numbers fixed. Maybe I can try varying the coordination numbers and see
if
it gives a different result.
I have attached the images of the pre-edge and main peak. Thanks and Regards
Disha From: Carlo Segre Hi Disha: it would be good to see the XANES you are referring to. Are the edges
identical or do they change but not shift significantly? Is the
coordination number also constant? Generally, the bond distance will
change with oxidation state if the coordination number is constant but if
the coordination number changes, then there could be a change in bond
length too. Cheers, Carlo On Mon, 11 Jun 2018, Disha Gupta wrote: Dear All Firstly, I would like to say sorry if I have missed out on this
discussion
before but it would be great if you could help me out.
I have been analyzing some Mn K-edge XAS data for some battery
materials.
While the XANES data shows no shift in the main absorption peak which
means
that there is no oxidation change happening, however, when I am fitting
the
data in Artemis, I can see a shift in the bond lengths suggesting an
oxidation change. Is it possible that bond lengths change even though
XANES
spectra show no change? Thank you and Kind Regards
Disha --
Carlo U. Segre -- Duchossois Leadership Professor of Physics
Interim Chair, Department of Chemistry
Director, Center for Synchrotron Radiation Research and Instrumentation
Illinois Institute of Technology
Voice: 312.567.3498 Fax: 312.567.3494
segre@iit.edu http://phys.iit.edu/~segre segre@debian.org
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Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit Disha Gupta
Graduate Student
School of Materials Science and Engineering
Nanyang Technological University (NTU), Singapore
+65 84087404
DISHA001@e.ntu.edu.sg On Mon, Jun 11, 2018 at 11:34 AM, Disha Gupta Dear All Firstly, I would like to say sorry if I have missed out on this
discussion
before but it would be great if you could help me out.
I have been analyzing some Mn K-edge XAS data for some battery
materials.
While the XANES data shows no shift in the main absorption peak which
means
that there is no oxidation change happening, however, when I am fitting
the
data in Artemis, I can see a shift in the bond lengths suggesting an
oxidation change. Is it possible that bond lengths change even though
XANES
spectra show no change? Thank you and Kind Regards
Disha ----- Ende der Nachricht von Disha Gupta --
PD Dr. Claudia S. Schnohr
Institut f?r Festk?rperphysik
Friedrich-Schiller-Universit?t Jena
Max-Wien-Platz 1
D-07743 Jena
Germany Tel: +49 3641 947333
Fax: +49 3641 947302 ------------------------------ Message: 3
Date: Mon, 11 Jun 2018 09:59:23 -0400
From: Qingying Jia Hi Disha, The shift in bond distance in this case, is not necessarily associated
with the change of oxidation state. It can be simply caused by the
insertion/removal of Li/Na or whatever depending on your battery type
during the charge/discharge, which sometimes changes the oxidation state of
Mn slightly, sometimes doesn't. Regards, On Sun, Jun 10, 2018 at 11:34 PM, Disha Gupta Dear All Firstly, I would like to say sorry if I have missed out on this
discussion
before but it would be great if you could help me out.
I have been analyzing some Mn K-edge XAS data for some battery materials.
While the XANES data shows no shift in the main absorption peak which
means
that there is no oxidation change happening, however, when I am fitting
the
data in Artemis, I can see a shift in the bond lengths suggesting an
oxidation change. Is it possible that bond lengths change even though
XANES
spectra show no change? Thank you and Kind Regards
Disha _______________________________________________
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