Dear Sin-Yuen,
Your Au(I)Cl seems to be significantly oxidized to HAu(III)Cl4.
It can be judged by the pronounced pre-edge feature at ~11921 eV.
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 the paper attached.
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@get.obs-mip.fr; glebounet@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@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@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@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
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