- Ifeffit - millenia.cars.aps.anl.gov

Re: [Ifeffit] non-standard space group P 21/n
by andrea.sanson＠unipd.it 09 Dec '14

09 Dec '14

Dear Wayne, thank you very much for your enlightening answer! Best regards, Andrea Dear Andrea, To convert the atomic positions, use the following equations (starred positions are in the P21/c setting) a* = c b* = b c* = a+b To convert the unit cell,Â A* = C B* = B C* = sqrt{[Ccos(90-beta)]^2+[A-Csin(90-beta)]^2} beta* = 90 - cos-1[Ccos(90-beta)/C*] where cos-1 is the inverse cosine function If you have problems, please double check my geometry for converting the unit cell parameters. Sincerely, Wayne On Fri, Dec 5, 2014 at 9:04 AM, <andrea.sanson(a)unipd.it> wrote: Dear Gordon, thank you for your reply. I tried to use the space group P1, but the resulting local structure around the absorber atoms is completely different from that expected. Andrea HI Andrea, My suggestion, if you know where all the atoms are in the unit cell, is to use space group P1. It may be tedious and brute force in nature, but you won't have to worry about origin choices or non-standard space groups. You will still know which atoms are equivalent and can pick an appropriate one as your target atom. regards, Robert On Fri, Dec 5, 2014 at 8:07 AM, Sanson Andrea <andrea.sanson(a)unipd.it> wrote: Dear all does anyone know if is it possible to create with ATOMS the non-standard space group P 21/n ? Space group keywords are listed at the atoms website http://iffwww.iff.kfa-juelich.de/icp/atoms/atoms.sgml-7.html#ss7.4 but no keyword for P 21/n group is available. Thanks for any suggestion. Best regards, AS _______________________________________________ Ifeffit mailing list Ifeffit(a)millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit _______________________________________________ Ifeffit mailing list Ifeffit(a)millenia.cars.aps.anl.gov http://millenia.cars _______________________________________________ Ifeffit mailing list Ifeffit(a)millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit -- Wayne Lukens Staff Scientist Lawrence Berkeley National Lab _______________________________________________ Ifeffit mailing list Ifeffit(a)millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit

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Re: [Ifeffit] non-standard space group P 21/n
by andrea.sanson＠unipd.it 05 Dec '14

05 Dec '14

Dear Gordon, thank you for your reply. I tried to use the space group P1, but the resulting local structure around the absorber atoms is completely different from that expected. Andrea HI Andrea, My suggestion, if you know where all the atoms are in the unit cell, is to use space group P1. It may be tedious and brute force in nature, but you won't have to worry about origin choices or non-standard space groups. You will still know which atoms are equivalent and can pick an appropriate one as your target atom. regards, Robert On Fri, Dec 5, 2014 at 8:07 AM, Sanson Andrea <andrea.sanson(a)unipd.it> wrote: Dear all does anyone know if is it possible to create with ATOMS the non-standard space group P 21/n ? Space group keywords are listed at the atoms website http://iffwww.iff.kfa-juelich.de/icp/atoms/atoms.sgml-7.html#ss7.4 but no keyword for P 21/n group is available. Thanks for any suggestion. Best regards, AS _______________________________________________ Ifeffit mailing list Ifeffit(a)millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit _______________________________________________ Ifeffit mailing list Ifeffit(a)millenia.cars.aps.anl.gov http://millenia.cars

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non-standard space group P 21/n
by Sanson Andrea 05 Dec '14

05 Dec '14

Dear all does anyone know if is it possible to create with ATOMS the non-standard space group P 21/n ? Space group keywords are listed at the atoms website http://iffwww.iff.kfa-juelich.de/icp/atoms/atoms.sgml-7.html#ss7.4 but no keyword for P 21/n group is available. Thanks for any suggestion. Best regards, AS

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Re: [Ifeffit] Launching Athena on Mountain Lion (Mac OS 10.8)
by Kyler Carroll 04 Dec '14

04 Dec '14

Hello, I had posted a comment/question a few months back when I had initially installed Mountain Lion on my mac regarding iXAFS compatibility with XQuartz and the new OS not supporting X11 anymore. Since then I have received a few comments back and I found one solution to be the best. This was originally sent by Tsu-Chien Weng from SSRL (tsuchien(a)slac.stanford.edu) Please find the following solution below. Once you install XQuartz the rest will be done in the Terminal.app. This is a one time solution and I havent had any trouble thus far with the program. Hope this works as well for everyone else as it did for me. 1. Install XQuartz from <http://xquartz.macosforge.org/landing/> 2. open Terminal.app 3. cd /Applications/Utilities 4. sudo mkdir X11.app 5. cd X11.app 6. sudo ln -s ../XQuartz.app/Contents Thank you, Kyler J. Carroll, Ph.D. Assistant Project Scientist Department of NanoEngineering University of California, San Diego

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Regarding a fit for Fe(OTf)2
by pushkar shejwalkar 03 Dec '14

03 Dec '14

Dear All, I am experiencing problem during my fit for Fe(OTf)2 anhydrous. The problem is as follows. I collected the data and used a model to fit. The fitting values and other technical information is as below. The basic problem is Fe(OTf)2 in anhydrous condition is probably not cyrstalline because of which there are no crystal data available. Although .cif file is available for hexahydrate and tetra acetonitrile. But obviously it is not directly useful as I am looking for Fe(OTf)2 only. I used hexahydrate for fitting, and the fit information is given. Is this fit acceptable? *Now two questions* 1) Why do I not see any scattering or peak for Fe-S. I expected S to be a strong scatterer and would show a peak. Under given circumstances it looks like Fe is all surrounded by water and no triflate is present near Fe at all. Is this assumption even make sense (when the bottle said anhydrous) The bottle was not kept under inert condition (and its my fault), but does it mean Fe(OTf)2 is so hygroscopic and that it can actually form such hexahydrate to the full extent? OR there is some inherent problem with my fitting and collection itself. I used RBKG=1.0 2) Is anybody working on Fe(OTf)2 and had such or any other problem indicating that Fe(OTf)2 by itself is a bad choice of precursor because of its reactivity. Also any comments on purification method etc. does anybody know if crystal structure is available for Fe(OTf)2 anhydrous? I could not find it on the quick search or on CCDC. Any other site where I can get crystal data and .cif information? Thank you very much for all the help, I hope the question is asked appropriately and all the other information is provided, however, if anybody needs any other information please let me know. Thank you in an anticipation Best Pushkar Independent points : 16.1250000 Number of variables : 4 Chi-square : 7324.9401796 Reduced chi-square : 604.1187777 R-factor : 0.0195782 Measurement uncertainty (k) : 0.0001264 Measurement uncertainty (R) : 0.0004142 Number of data sets : 1 guess parameters: SO = 1.06525455 # +/- 0.05504541 [1.00000] delE = -2.32587026 # +/- 0.59606221 [-2.77870] delR = 0.00911122 # +/- 0.00503027 [-0.02322] ss = 0.00706809 # +/- 0.00071967 [0.00300] Correlations between variables: delr & dele --> 0.9154 ss & so --> 0.9023 All other correlations below 0.4 name N S02 sigma^2 e0 delr Reff R ========================================================================= O1.1 6.000 1.065 0.00707 -2.326 0.00911 2.09150 2.10061 -- Best Regards, Pushkar Shejwalkar. Post-doctoral -Researcher,JSPS Fellow Hokkaido University, Sapporo, Japan [image: Inline image 3]

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Re: [Ifeffit] A small query on constricting mean square displacement in multi-edge EXAFS refinement
by Badari Rao 03 Dec '14

03 Dec '14

Dear Scott, Thank you for the answer. Date: Wed, 3 Dec 2014 08:03:56 -0500 > From: Scott Calvin <scalvin(a)sarahlawrence.edu> > To: XAFS Analysis using Ifeffit <ifeffit(a)millenia.cars.aps.anl.gov> > Subject: Re: [Ifeffit] A small query on constricting mean square > displacement in multi-edge EXAFS refinement > Message-ID: <A7199A7A-EA1B-4396-960B-301A94F68648(a)slc.edu> > Content-Type: text/plain; charset="utf-8" > > Yes. > > The only minor adjustment I can think of to that is something called the > ?McMaster correction,? which adjusts for an oversimplification in the usual > EXAFS method of normalization, and thus can be different for the two edges. > But that correction is generally quite small, and the difference in it > between two edges is even smaller. > > ?Scott Calvin > Sarah Lawrence College > > > On Dec 3, 2014, at 7:54 AM, Badari Rao <badari.rao(a)gmail.com> wrote: > > > > Dear All, > > > > Suppose I have a compound, say AB. I have the EXAFS data from both > A-edge as well as B-edge and I am simultaneously refining these data. > > Would it be correct to force the mean square displacement of the A-B > path in both the edges to be the same? > > > > -- Regards, > > Badari Narayana. A. R. > > Ph.D Student, Nanoscience and Nanotechnology, > > c/o Prof Rajeev Ranjan, > > Electroceramics Lab, > > Department of Materials Engineering, > > Indian Institute of Science. > > > > _______________________________________________ > > Ifeffit mailing list > > Ifeffit(a)millenia.cars.aps.anl.gov > > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit >

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Fit a mixture
by kaziz sameh 03 Dec '14

03 Dec '14

Dear All,I look for advice or document that can help me to fit the FT EXAFS data of Pd2Au36(SR)24.The situation is as follows:In the sample there is 3 sites of the Pd ( in staples, in surface or in the core). the spectrum that I have presents a first bond of Pd_S and second bond of Pd_Au, so the palladium should be in the staples or in the surface because in core we cannot see Pd-S, but other results of the same sample confirm that the palladium is in core.I concluded that there is a mixture of some nano (x ) with Pd in staple and another nano(y) with Pd in core such y>x.Note that I fit the data with Pd2Au36(SR)24 structure in which I put the 2 palladium in the staple and I have got a good fit (attached) but I think that is not logical.If you can help me with an idea how to fit this mixture, I would be very grateful.Kaziz.

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A small query on constricting mean square displacement in multi-edge EXAFS refinement
by Badari Rao 03 Dec '14

03 Dec '14

Dear All, Suppose I have a compound, say AB. I have the EXAFS data from both A-edge as well as B-edge and I am simultaneously refining these data. Would it be correct to force the mean square displacement of the A-B path in both the edges to be the same? -- Regards, Badari Narayana. A. R. Ph.D Student, Nanoscience and Nanotechnology, c/o Prof Rajeev Ranjan, Electroceramics Lab, Department of Materials Engineering, Indian Institute of Science.

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open position at KIT
by Lichtenberg, Henning (IKFT) 02 Dec '14

02 Dec '14

Dear XAS community, we have an open position in the field of EXAFS and operando spectroscopy in our group. For further information see the attached job description. Please feel to contact us also if you are interested in a beamline scientist position or x-ray microscopy. with best regards, Henning Lichtenberg

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S XANES question
by Matthew Marcus 26 Nov '14

26 Nov '14

A user on ALS 10.3.2 is taking S K-edge XANES and consistently finding a strong peak at 2484eV (calibration: gypsum white line = 2482.75eV). There's a shoulder at the nominal position of the sulfate peak. Now, peaks below sulfate I can understand, but since there's no such thing as heptavalent sulfur, what could give a peak *above* the sulfate white line? Anybody ever seen that? Yes, we checked calibration. mam

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