September 2009 - Ifeffit - millenia.cars.aps.anl.gov

Athena User Guide—FCFS
by Julie Olmsted Cross 09 Nov '09

09 Nov '09

I have ten copies of the Athena User Guide leftover from the 2009 APS XAFS School. If you want one, send me your mailing address. First come, first served. ~^^~^~^~~^~^~^~^~^~^~^~^~~^~^~ Dr. Julie O. Cross User Technical Interface APS Engineering Support Division Argonne National Laboratory 9700 South Cass Ave., Bldg. 401/B4204 Argonne IL 60439-4801 tel: 630 252 0592 fax: 630 252 7187 ~^^~^~^~~^~^~^~^~^~^~^~^~~^~^~

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Got Athena data plotted
by abhijeet gaur 28 Oct '09

28 Oct '09

Thanks a lot kicaj, I followed the procedure step by step and I got the data plotted in Excel. Thanks again Kicaj. Abhijeet

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Cementite EXAFS
by Andrew 25 Sep '09

25 Sep '09

Bhoopesh, I would trust the XAFS.org spectrum more than mine, I'm sure that the APS has a better resolution etc. I'm aware that there are other forms of reduced iron carbide, but I did nothing special except for following the Li et al. paper. I then tried to see if the spectrum was similar to both the one on Dr. Newville's database as well as the Iglesia and coworkers' papers, and they were. I know this data is a bit glitchy... and I was pretty much only interested in the XANES. If the person that Dr. Newville is referring to made the Fe3C from the iron melt it would have been a white powder, so they likely did a similar procedure as reducing the Fe2O3 std. to a sufficient temperature (at 1 atm). I have also heard from a former Exxon researcher that when they wanted to make cementite they simply CO reduced Fe2O3 to a sufficient temperature as well. I'm forwarding this directly to your e-mail as well. Hope this helps, if not (try and comparing it with the one on the XAFS.org, I remember when I checked it was similar). Andrew Campos

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Cementite EXAFS - thanks
by Bhoopesh Mishra 24 Sep '09

24 Sep '09

Hi Scott and Mathew, Thanks for pointing me to Matt Newville's archive. It is a great resource to have and I have used it on several occasions. However, what I found on that database is "Fe3C". Since there are couple of different local environments for Fe3C, and not all of them are Cementite - I am not sure if that would be a good standard for me. Nevertheless, it served as a good starting point. It would be great if Andrew can send us his data. Thanks again, Bhoopesh On Thu, Sep 24, 2009 at 11:54 AM, Scott Calvin <SCalvin(a)slc.edu> wrote: > Hi Bhoopesh, > > There are files that are identified as cementite in Matt Newville's > archive: > > http://cars9.uchicago.edu/~newville/ModelLib/search.html<http://cars9.uchicago.edu/%7Enewville/ModelLib/search.html> > > If you manage to get any other data, let me know; I've used the > standard at the link above, but I'd like to confirm it. > > --Scott Calvin > Sarah Lawrence College > > On Sep 24, 2009, at 11:45 AM, bhoopeshm wrote: > > > Dear All, > > I am writing to see if anyone on this mailing list has > > ever measured "Cementite" (Fe3C) EXAFS. It is basically an Iron > > Carbide, nothing exotic at all. > > > > I would be very grateful to anyone who might want to share an EXAFS > > spectrum of Cementite (Fe3C). > > > > > > Regards, > > Bhoopesh > _______________________________________________ > Ifeffit mailing list > Ifeffit(a)millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit >

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Cementite EXAFS
by Andrew 24 Sep '09

24 Sep '09

Bhoopesh, There's a paper which says how to make it if you want to run it on your own: "Fe3C, which can form during FTS reactions, was prepared by temperature-programmed reaction (0.167 K/s) of Fe2O3 up to 973 K using CO (Matheson, 99.99%, 107 mol of CO/mol of Fe h) as the reduction and carburization agent. The resulting Fe3C powder was passivated in flowing 1% O2/ He (Matheson, 99.999%, 0.05 mol/h) at room temperature (RT) for 1 h before removing the sample from the synthesis cell." [1] S. Li, G.D. Meitzner and E. Iglesia, J. Phys. Chem. B, 105 (2001) 5743. I made some myself using this method. I would send my spectrum, but if I can recall we had glitches in the EXAFS region. Andrew Campos ** If you want other iron carbides, this will be quite tricky since this is the only one that can be synthesized to a pure extent... obviously one could make cementite to using an iron melt but that requires really high temperature furnaces etc.

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mu(E) of theoretically calculated spectra
by abhijeet gaur 24 Sep '09

24 Sep '09

Hi all, I am doing the theoretical fitting using Artemis. But I am unable to get the mu(E) of theoretically calculated spectra in Artemis. If I got it correctly, Artemis plot the theoretical spectra using FEFF code. But it gives chi(k) and chi(R). Is there any way to get mu(E) from this chi(k) spectra. Or in order get the theoretically calculated mu(E) spectrum of the given structure , we have to use FEFF code alone. How it can be done? with thanks Abhijeet Gaur Vikram University Ujjain (INDIA)

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job postings
by Matt Newville 22 Sep '09

22 Sep '09

Hi Folks, There have been two post-doc positions posted at http://xafs.org/Jobs recently. If you know of anyone who might be interested, please pass these along. Cheers, --Matt Newville

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Re: [Ifeffit] Ifeffit Digest, Vol 79, Issue 9
by abhijeet gaur 20 Sep '09

20 Sep '09

The FEFF6L distributed with Ifeffit is only set up to calculate EXAFS. If you want the near edge structure, you will have to use FEFF8 separately. Hello Carlo Sir, Sorry to give you trouble again about the same reply of yours. Is it possible to get mu(E) of EXAFS, say beyond 20-50 eV through FEFF6L distributed with Ifeffit . with regards Abhijeet

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Re: [Ifeffit] Ifeffit Digest, Vol 79, Issue 8
by abhijeet gaur 19 Sep '09

19 Sep '09

Hi Abhijeet: The FEFF6L distributed with Ifeffit is only set up to calculate EXAFS. If you want the near edge structure, you will have to use FEFF8 separately. Cheers, Carlo Hello Carlo Sir, Thanks for your quick response. But if you can tell me, from where I can get FEFF8 to calculate the near edge structure, it will be very helpful to me. with regards Abhijeet

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XANES spectrum of cobalt carbide
by Xiaoming Wang 19 Sep '09

19 Sep '09

Dear All, I am doing the analysis of some unknown cobalt-containing samples, and I suspect that there might be cobalt carbide there. Thus I am wondering if anybody has a cobalt K edge XANES spectrum of cobalt carbide to share. Your help will be greatly appreciated! Many thanks! Xiaoming Wang Yale University

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