[Ifeffit] How to identify N and O atoms in the first coordinate

[mzhu at udel.edu]

Hello JeongEunSuk,
  Following your recommendation, I do find the pre-edge peak corresponding to s->d electron transition slightly shifts to higher energy for a nickel nitrogen-coordinated organic reference than for a nickel oxygen-coordinated organic reference. But the peak position is nearly the same for the nitrogen-coordinated organic reference with the aqueous nickel solution. I guess it is because the long Ni-OH2 bond in the aqueous nickel solution which also results in a less electron density on nickel(higher oxidation state). I will think about that. Thanks for your recommendations.  

Best wishes,

Mengqiang Zhu   







-----------------------
Mengqiang Zhu
Ph.D Candidate 
Environmental Soil Chemistry
Department of Plant and Soil Sciences 
University of Delaware
152 Townsend Hall
Newark, DE 19716 
http://ag.udel.edu/soilchem/zhu.html 


---- Original message ----
>Date: Sat, 20 Dec 2008 16:02:44 +0900
>From: ifeffit-bounces at millenia.cars.aps.anl.gov (on behalf of JeongEunSuk <eunsuk1986 at hotmail.com>)
>Subject: Re: [Ifeffit] How to identify N and O atoms in the first coordinate  
>To: ifeffit <ifeffit at millenia.cars.aps.anl.gov>
>
>   Hello mzhu
>    
>   I think that it is impossible to distinguish
>   nitrogen with oxygen by using EXAFS. I would like
>   to recommend XANES for your study.
>   The shift of pre-edge of XANES shows how the
>   oxidation state of metal is changed.
>   As you know, If there are nitrogen atoms in
>   substitute for oxygen atoms  around metal,  the
>   pre-edge of metal xanes may shift to high energy
>   because the oxidation state increases.
>    
>
>   > From: mzhu at udel.edu
>   > To: ifeffit at millenia.cars.aps.anl.gov
>   > Date: Fri, 19 Dec 2008 16:20:39 -0500
>   > Subject: [Ifeffit] How to identify N and O atoms
>   in the first coordinate
>   >
>   > Hello all,
>   > Merry Christmas!
>   > I have some samples of heavy metal sorption on
>   bacterial biofilm. I want to figure out what
>   elements are coordinated with the heavy metal in the
>   first coordinate. Since the oxygen and nitrogen have
>   similar scattering factors, how can I differetiate
>   them? Using shell-by-shell fitting or linear
>   combination fitting with standards? Thanks.
>   >
>   > Best wishes,
>   >
>   > Mengqiang Zhu
>   >
>   >
>   >
>   >
>   >
>   >
>   >
>   > -----------------------
>   > Mengqiang Zhu
>   > Ph.D Candidate
>   > Environmental Soil Chemistry
>   > Department of Plant and Soil Sciences
>   > University of Delaware
>   > 152 Townsend Hall
>   > Newark, DE 19716
>   > ! http://ag.udel.edu/soilchem/zhu.html
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