[Ifeffit] Fwd: Re: Solid AuCl EXAFS fitting – big N

[Gleb Pokrovski]

Dear Sin-Yuen,

Your Au(I)Cl seems to be significantly oxidized to HAu(III)Cl4,
as can be judged by the pronounced pre-edge feature at ~11921 eV, 
typical of square-coordinated Au(III) compounds.

I added a few (likely good!) spectra of Au(III) and Au(I) chloride 
reference compounds
to your athena file (attached), together with the  paper in which they 
were published.

My AuCl(s) looks much less oxidized than yours, but still might be 
somewhat altered;
the best Au(I)Cl2 reference, to my opinion, is the aqueous AuCl2(-) 
complex, which is stable
in acidic Cl solutions at elevated temperatures (included in the file).
Please feel free to use these spectra by referring to this paper.

best regards

Gleb

Dr. Gleb S. Pokrovski
Directeur de Recherche CNRS
Associate Editor of Economic Geology
Associate Editor of Geochimica et Cosmochimica Acta
Geosciences Environnement Toulouse (ex-LMTG)
GET - UMR 5563 of CNRS, University of Toulouse III
14 avenue  Edouard Belin , F- 31400 TOULOUSE, France
e-mail:gleb.pokrovski at get.obs-mip.fr;glebounet at gmail.com
phone: 33-5-61-33-26-18 , fax: 33-5-61-33-25-60

On 27/06/2014 20:11, Sin Yuen Chang wrote:
> Many thanks for the response, Bruce.
>
>> For something as tricky as Au(1+) chloride, I think it is unwise to
>> blindly trust data that you found in some disreputable corner of the
>> internet.  It really seems like the kind of thing you need to measure
>> for yourself if you want confidence in what you have.
> Exactly what I am working on!
>
> Best regards,
> Sin-Yuen
>
> -----Original Message-----
> From:ifeffit-bounces at millenia.cars.aps.anl.gov  [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf Of Bruce Ravel
> Sent: 27 June 2014 16:40
> To: XAFS Analysis using Ifeffit
> Subject: Re: [Ifeffit] Solid AuCl EXAFS fitting – big N
>
> On 06/27/2014 01:14 AM, Sin Yuen Chang wrote:
>> Given how many times AuCl XANES has been published before, has anyone
>> else perhaps run into this problem? Has anyone perhaps measured solid
>> AuCl under exclusion of moisture and air, or several times as a
>> function of time to assess beam damage?
>>
> I was under the impression that *everyone* runs into that problem.  As you say Au(1+) chloride is quite unstable.  Given that the white line in the data that you took from my LCF fitting example is so close in size to that of Au(3+) chloride, I would guess that the sample was no pure Au(1+) by the time we measured it.
>
> For something as tricky as Au(1+) chloride, I think it is unwise to blindly trust data that you found in some disreputable corner of the internet.  It really seems like the kind of thing you need to measure for yourself if you want confidence in what you have.
>
> B
>
> --
>    Bruce Ravel  ------------------------------------bravel at bnl.gov
>
>    National Institute of Standards and Technology
>    Synchrotron Science Group at NSLS --- Beamlines U7A, X24A, X23A2
>    Building 535A
>    Upton NY, 11973
>
>    Homepage:http://xafs.org/BruceRavel
>    Software:https://github.com/bruceravel
> _______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>
> _______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20140630/b645debd/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: AuCl_solid_GP.prj
Type: application/octet-stream
Size: 65432 bytes
Desc: not available
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20140630/b645debd/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: AuCl_xafs_ChemGe_2009.pdf
Type: application/pdf
Size: 755040 bytes
Desc: not available
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20140630/b645debd/attachment.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: AuCl_xafs_ChemGe_2009_supplement.pdf
Type: application/pdf
Size: 59484 bytes
Desc: not available
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20140630/b645debd/attachment-0001.pdf>