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

Fe foil at 900 C
by KONG Quingyu 12 Jun '11

12 Jun '11

Hello, We are measuring the kinetic of carbon nanotubes using Fe as catalytic element. To analyze the data, we need the Gamma iron (Fe fcc, iron foil measured with a temperature between 910 and 1400 C) EXAFS spectrum. We appreciate if anyone could send us this spectrum. Thanks a lot in advance, Sincerely Qingyu Kong Beamline ODE Société civile Synchrotron SOLEIL L'Orme des Merisiers Saint-Aubin - BP 48 91192 GIF-sur-YVETTE CEDEX Tel: +33 (0)1 69 35 97 84 (office) +33 (0)1 69 35 97 16 (beamline) email: kong(a)synchrotron-soleil.fr ________________________________________ From: ifeffit-bounces(a)millenia.cars.aps.anl.gov [ifeffit-bounces(a)millenia.cars.aps.anl.gov] on behalf of ifeffit-request(a)millenia.cars.aps.anl.gov [ifeffit-request(a)millenia.cars.aps.anl.gov] Sent: Wednesday, June 08, 2011 9:03 AM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: Ifeffit Digest, Vol 100, Issue 6 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: Question about shift in E0 (Christopher Patridge) 2. Re: Question about shift in E0 (Brandon Reese) ---------------------------------------------------------------------- Message: 1 Date: Mon, 6 Jun 2011 21:55:25 -0400 From: Christopher Patridge <patridge(a)buffalo.edu> To: XAFS Analysis using Ifeffit <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] Question about shift in E0 Message-ID: <D53A5E8D-B912-4E7B-A567-2E0BB79B4B06(a)buffalo.edu> Content-Type: text/plain; charset="us-ascii" Brandon, I have a question about your method. You mention that you pick E0 based on the 1st peak of the derivative for each sample then extract chi(k). Have you tried constraining E0 across the set? I have thought that in order to make a good comparison between samples in a set, a common E0 should be chosen in order to replicate closely the background function across the whole set. Constraining may also provide a trend in the fitting. Buena salud, Chris On Jun 6, 2011, at 6:46 PM, Brandon Reese <bjreese(a)gmail.com> wrote: > Kicaj and Matt, > > Thanks for the replies. It is certainly reasonable to ask about the experimental setup, that seems like a good first place to look for oddities. Sorry about using E0 in two different contexts (Athena and Artemis). I'll switch to using E0 for the chosen parameter in Athena's background subtraction and Enot for the guess parameter in Artemis. > > I aligned the scans in Athena using the reference foil absorption edge. I ended up shifting the scans in energy by ~1 eV or less based on the reference foil. I then set the E0 parameter in Athena to the peak of the first derivative. This value varied by about 0.5 eV (or less) between the different samples. This is what I considered when I made the statement about not seeing the oxidation change in the XANES. There is a shift of about 4 eV compared to the reference foil, which I would expect because I am looking at oxides. > > I then extracted the chi(k) into Artemis, and used the same Feff calculations/paths for each sample. In the Artemis fits I am seeing Enot shifts of 1-2 eV, which is a fair bit larger than the error bars. If I chose E0 at peak of the first derivative the Enot came out to be ~7 eV. Since this seemed a little on the big side, I also tried setting E0 to be the top of the white line, in that case Enot came out to be ~1 eV. The Enot shift between samples was about the same either way. Could an argument be made that there is a small shift in the overall oxidation state of the films, possibly contributing to the changes in the conductivity changes in the films? Does anyone have any references about using Enot shifts in this way? > > Scott - The amplitudes of the XANES features are very close. in the normalized spectrum the difference practically 0, and in the derivative the amplitudes are ~5% off. There is bit larger of a difference in amplitude between the samples (in fluorescence) and a pure In2O3 powder (in transmission) of ~10% in the first derivative. The samples are sputtered from oxide sources, so the presence of metallic In should be pretty small. I am interested about your comment on the relative sizes of the first derivative peaks. Comparing my samples to the foil the oxide peak amplitude is bigger than the metal peak by 10% or so. Could this be due to the differences between fluorescence and transmission or not optimizing the experiment to measure the foil? Or could it be due to something else more heinous? > > I noticed on individual fits that the dR for the first shell came out nearly the same (2.162 +/- .007 vs. 2.164) on the two samples, while the Enot's had the 1-2 eV shift between the samples. I tried to fit the two types of samples simultaneously while constraining the dR's (and a few 2nd shell parameters) to be equal to each other and letting the Enot's float. The relative Enot values came out close to what they were before. If I let dR values fit independantly, there was no real change present. In other words the multiple data set fit just made my EB's a bit smaller, but the relative shifts stayed about the same. > > Would there be some reasonable way in a multi-data set fit to constrain the Enot's? > > Brandon > > On Mon, Jun 6, 2011 at 9:04 AM, Matt Newville <newville(a)cars.uchicago.edu> wrote: > HI Brandon, > > If I understand right (and to echo Darius's questions), it seems like > you measure samples with a metal reference, and aligned the spectra in > Athena so that the references matched. That's a fine way to go. I > would ask: how big were the needed energy shifts? > Are the experimental mu(E) spectra aligned well at this point? If > you're studying metal oxides with different oxygen content, you might > very well see oxidation in the XANES. If I understand correctly, > you're saying you don't see this. > > Then, you extracted the chi(k) from the aligned spectra. How much did > E0 vary for the shifted spectra in this background-subtraction step? > > Then, you pulled these chi(k) into Artemis, and see different E0 > shifts in the fits. This E0 is a little different, in that it is the > E0 shift applied to the Feff calculation to match the experimental > spectra. If you use different paths or different calculations, such > E0 shifts might happen, and wouldn't be highly meaningful. > > I know that's not a complete answer, but hopefully that and Darius's > questions will help, > > --Matt > > PS on Q2: 1/ (kR)^2 vs 1 / kR^2 > > This is probably either a typo, or a different convention based on the > definition of f(k) as the electron scattering amplitude. In the Feff > world, it should be 1/kR^2, but using 1/(kR)^2 would just map f(k) to > k*f(k). > _______________________________________________ > 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.aps.anl.gov/mailman/listinfo/ifeffit

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Postdoc in XAFS at Australian Synchrotron
by Chris Glover 11 Jun '11

11 Jun '11

Hi All, Im hoping this reaches, or could be passed to, interested candidates in a 2 year Postdoc position at the XAS beamline at the Australian Synchrotron. In short the beamline is based on a 1.9T Wiggler with high flux focused beam of ~ 0.2 x 1 mm. It features 2 experimental hutches, the first is a (fixed) 'standard' RT/He transmission / fluorescence setup, and the second flexible for a range of different setups. The main detector on the beamline is a Canberra 100 element Ge pixel array detector and XIA electronics. Optimizing the experimental performance of this detector be the main focus of the Postdocs project. Further information regarding the beamline and the position are available at: http://www.synchrotron.org.au/index.php/aussyncbeamlines/x-ray-absorption-s… http://www.synchrotron.org.au/index.php/about-us/working-at-the-synchrotron… Relocation and repatriation expenses for international candidates will be provided. I would like to clarify that despite rumors and what may be reported in the local and international media, we are not concerned about the long term security and viability of the Australian Synchrotron continued operations. We are, unfortunately, a hot topic with local politics. For any queries or further information please contact me off the list. Regards Chris Glover.

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Question about shift in E0
by Brandon Reese 08 Jun '11

08 Jun '11

Hi all, I am looking at EXAFS of thin film metal oxides. I am varying both metal content and the oxygen content of the films. I aligned the scans with a metal reference foil collected simultaneously. In Artemis, I have noticed that when changing between films with no extra oxygen versus those with extra oxygen there is a shift in the fitted E0 of ~1.5 eV (after aligning to the foil). I tried setting the E0 in Athena to the peak of the 1st derivative and the peak of the white line with the same result (~7 eV difference). I was a little surprised by the offset because in Athena the E0 values varied by <0.5 eV. I am not sure if the argument could be made that this shift is a result in a changing oxidation state because it doesn't show up in the XANES (at least qualitatively). Are there other experimental effects that could cause a shift like this, or is this likely something real in my material? If anyone want to see a representative group of data, let me know. I also have an unrelated quick (I think) question on the EXAFS equation. In some references I see a term 1/(k R)^2 and in others it is 1/(k R^2). I couldn't really see any reason for the difference, unless it is to correct for subtle differences in how the other terms are defined. Thanks Brandon

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Re: [Ifeffit] Question about shift in E0
by Andrew Korinda 07 Jun '11

07 Jun '11

Sorry Brandon, I see now everything I was asking for was I'm the first few emails. Enot is a local atomic shift in E0 as explained before. (sorry I'm not referencing, I only have my phone available this week) What I understand is you have set E0 to 27944 and 27950 then get Enot of -7 and -1 respectively. This leads to a local edge in the EXAFS equation of 27951 in both cases which is what I was getting at previously. But you say ~ so that means you have an real difference between the two, and the opposite of what I was thinking. Sorry if I caused any confusion. Andy Korinda On Jun 7, 2011 6:27 AM, "Brandon Reese" <bjreese(a)gmail.com> wrote: > I was using feff6. Does your comment mean that when fitting Enot with Feff6, > the results should be considered unreliable? I assumed the 0.5 eV shift in > the mu spectra was small enough that the spectrum could be considered > essentially at the same energy. That is why I was surprised with the > (somewhat) larger shift in Artemis. > > Andy, are you asking what the difference is between E0-Enot for the two > samples? If I picked E0 to be 27944 for all the samples( a round number near > the 1st derv peak), Artemis would fit Enot to be ~5.5 for one group of > samples and ~7 for the other group. Approximately the same offset was > present if I let the parameters get chosen automatically, regardless of the > absolute E0 (within reason). Is this what you were asking, or did I > misunderstand? > > Brandon > > Andy, E0-Enot came out to be 2794 > 2011/6/7 "Dr. Dariusz A. Zając" <kicaj(a)ifj.edu.pl> > >> ** >> Hi Brandon, >> that was a reason why I wanted to clarify which parameters you use. >> E0 (as a Fermi level) in Athena can be taken (but do not must) as a valence >> state of measured ion for K edges, whereas in Artemis delE0 can correspond >> to the potential of the one of nearest atoms to the measured one. If you >> talk about Artemis and calculations, would be also helpful to know the >> version of feff. It is known that for version up to 6. can be problem with >> fitting values of Enot. And of course Matt answered you more clearly... >> The difference of 0.5eV between spectra of reference sample can be simply >> related with the energy resolution of the beam (beamline). >> >> Maybe this will helps you more: >> http://cars9.uchicago.edu/pipermail/ifeffit/2004-June/005607.html >> http://cars9.uchicago.edu/pipermail/ifeffit/2006-February/006811.html >> >> kicaj >> >> W dniu 11-06-07 00:46, Brandon Reese pisze: >> >> Kicaj and Matt, >> >> Thanks for the replies. It is certainly reasonable to ask about the >> experimental setup, that seems like a good first place to look for oddities. >> Sorry about using E0 in two different contexts (Athena and Artemis). I'll >> switch to using E0 for the chosen parameter in Athena's background >> subtraction and Enot for the guess parameter in Artemis. >> >> I aligned the scans in Athena using the reference foil absorption edge. I >> ended up shifting the scans in energy by ~1 eV or less based on the >> reference foil. I then set the E0 parameter in Athena to the peak of the >> first derivative. This value varied by about 0.5 eV (or less) between the >> different samples. This is what I considered when I made the statement about >> not seeing the oxidation change in the XANES. There is a shift of about 4 eV >> compared to the reference foil, which I would expect because I am looking at >> oxides. >> >> I then extracted the chi(k) into Artemis, and used the same Feff >> calculations/paths for each sample. In the Artemis fits I am seeing Enot >> shifts of 1-2 eV, which is a fair bit larger than the error bars. If I chose >> E0 at peak of the first derivative the Enot came out to be ~7 eV. Since this >> seemed a little on the big side, I also tried setting E0 to be the top of >> the white line, in that case Enot came out to be ~1 eV. The Enot shift >> between samples was about the same either way. Could an argument be made >> that there is a small shift in the overall oxidation state of the films, >> possibly contributing to the changes in the conductivity changes in the >> films? Does anyone have any references about using Enot shifts in this way? >> >> Scott - The amplitudes of the XANES features are very close. in the >> normalized spectrum the difference practically 0, and in the derivative the >> amplitudes are ~5% off. There is bit larger of a difference in amplitude >> between the samples (in fluorescence) and a pure In2O3 powder (in >> transmission) of ~10% in the first derivative. The samples are sputtered >> from oxide sources, so the presence of metallic In should be pretty small. I >> am interested about your comment on the relative sizes of the first >> derivative peaks. Comparing my samples to the foil the oxide peak amplitude >> is bigger than the metal peak by 10% or so. Could this be due to the >> differences between fluorescence and transmission or not optimizing the >> experiment to measure the foil? Or could it be due to something else more >> heinous? >> >> I noticed on individual fits that the dR for the first shell came out >> nearly the same (2.162 +/- .007 vs. 2.164) on the two samples, while the >> Enot's had the 1-2 eV shift between the samples. I tried to fit the two >> types of samples simultaneously while constraining the dR's (and a few 2nd >> shell parameters) to be equal to each other and letting the Enot's float. >> The relative Enot values came out close to what they were before. If I let >> dR values fit independantly, there was no real change present. In other >> words the multiple data set fit just made my EB's a bit smaller, but the >> relative shifts stayed about the same. >> >> Would there be some reasonable way in a multi-data set fit to constrain the >> Enot's? >> >> Brandon >> >> On Mon, Jun 6, 2011 at 9:04 AM, Matt Newville <newville(a)cars.uchicago.edu >wrote: >> >>> HI Brandon, >>> >>> If I understand right (and to echo Darius's questions), it seems like >>> you measure samples with a metal reference, and aligned the spectra in >>> Athena so that the references matched. That's a fine way to go. I >>> would ask: how big were the needed energy shifts? >>> Are the experimental mu(E) spectra aligned well at this point? If >>> you're studying metal oxides with different oxygen content, you might >>> very well see oxidation in the XANES. If I understand correctly, >>> you're saying you don't see this. >>> >>> Then, you extracted the chi(k) from the aligned spectra. How much did >>> E0 vary for the shifted spectra in this background-subtraction step? >>> >>> Then, you pulled these chi(k) into Artemis, and see different E0 >>> shifts in the fits. This E0 is a little different, in that it is the >>> E0 shift applied to the Feff calculation to match the experimental >>> spectra. If you use different paths or different calculations, such >>> E0 shifts might happen, and wouldn't be highly meaningful. >>> >>> I know that's not a complete answer, but hopefully that and Darius's >>> questions will help, >>> >>> --Matt >>> >>> PS on Q2: 1/ (kR)^2 vs 1 / kR^2 >>> >>> This is probably either a typo, or a different convention based on the >>> definition of f(k) as the electron scattering amplitude. In the Feff >>> world, it should be 1/kR^2, but using 1/(kR)^2 would just map f(k) to >>> k*f(k). >>> _______________________________________________ >>> Ifeffit mailing list >>> Ifeffit(a)millenia.cars.aps.anl.gov >>> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit >>> >> >> >> _______________________________________________ >> Ifeffit mailing listIfeffit@millenia.cars.aps.anl.govhttp:// millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit >> >> >> >> _______________________________________________ >> 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] Question about shift in E0
by Scott Calvin 06 Jun '11

06 Jun '11

Hi Brandon, I don't find this terribly surprising if your samples are mixtures of a metal and a metal oxide. If you look at the derivative of the XANES spectra of a pure transition metal and its oxides, you'll generally find that the biggest difference is not in the position of the derivative peaks, but in their relative size; for the metal the lower energy derivative peak is much larger than it is for the oxide. A mixture of oxide and metal, therefore, will be primarily evident in XANES through the relative heights of these peaks; sometimes the apparent shift can be very subtle indeed. For example, consider what happens if the first peak in the first derivative is 20 times lower in the oxide than in the metal, and is also 1.5 eV higher in energy. If you have one sample which is 70% metal, and you compare it to a sample which is 40% metal, the tiny contribution of the oxide to the first peak will hardly be visible in either case, and you might see no measurable shift in energy in the XANES for that peak. (You'll see a big change in its amplitude, though.) Likewise, the white line may be dominated by the oxide, and show little shift in the XANES (but once again, a big change in amplitude). An EXAFS fit, however, doesn't suffer from weighting issues in the same way, and may indeed show an E0 shift when the mixture of oxidation states changes. For my description to apply to your system, though, I'd expect you to be seeing substantial changes in the amplitudes of XANES features, even if their position doesn't shift much. Is that the case for your data? --Scott Calvin Sarah Lawrence College On Jun 5, 2011, at 11:56 PM, Brandon Reese wrote: > Hi all, > > I am looking at EXAFS of thin film metal oxides. I am varying both > metal content and the oxygen content of the films. I aligned the > scans with a metal reference foil collected simultaneously. In > Artemis, I have noticed that when changing between films with no > extra oxygen versus those with extra oxygen there is a shift in the > fitted E0 of ~1.5 eV (after aligning to the foil). I tried setting > the E0 in Athena to the peak of the 1st derivative and the peak of > the white line with the same result (~7 eV difference). I was a > little surprised by the offset because in Athena the E0 values > varied by <0.5 eV. I am not sure if the argument could be made that > this shift is a result in a changing oxidation state because it > doesn't show up in the XANES (at least qualitatively). Are there > other experimental effects that could cause a shift like this, or is > this likely something real in my material? If anyone want to see a > representative group of data, let me know. > > >

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Startup Macros
by Emiliano Fonda 31 May '11

31 May '11

Dear all, I would like to write some IFeffit macro and use it in Athena. Actually, I did not find a clean way to load a file with macros at the Athena startup. How can we add our own macros to those that are built-in? Best regards, Emiliano -- Dr. Emiliano Fonda Beamline Scientist (SAMBA) Synchrotron SOLEIL L'Orme des Merisiers Saint Aubin BP48 91192 Gif Sur Yvette CEDEX France Phone +33169359633 Fax +33169359456

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Re: [Ifeffit] more bugs in atoms?
by Gudrun Lisa Bovenkamp 27 May '11

27 May '11

Hi George, I cannot understand how you got this atoms.inp file where the core is stated to be Co1 and there is only Fe. So, I cannot confirm the crystal structure from a database. My problem is solved. I understood that the ATOMS program implemented in Arthemis and ATOMS 2.5 have some bugs that are corrected in ATOMS 3.0 and WebATOMS. When I use those two programs I get a correct crystal structure xyz table in feff.inp. the only reason that I can think of, why your shifting seem to work better is that the atoms.inp file was not representing the correct structure in the first place. This can happen when the situation you wnat to describe is not the situation that was measured by somebody else. Or there is a mistake in the paper. Anyway. Thanks for sharing this idea. Lisa > Date: Thu, 26 May 2011 11:41:08 -0400 >From: George Sterbinsky <GeorgeSterbinsky(a)u.northwestern.edu> > To: XAFS Analysis using Ifeffit <ifeffit(a)millenia.cars.aps.anl.gov> > Subject: Re: [Ifeffit] more bugs in atoms? > Message-ID: <BANLkTi=OH=NCJjmwhkE5vLmnTEao8k3avg(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Lisa, > > Let me just mention one situation I have encountered using atoms, >and how I > resolved it. I am not sure if this is the result of a bug or not, >but > perhaps you can try applying the approach I took to your own >situation and > see if it can resolve your problem. > > The issue I encountered was running atoms for a monoclinic I2/c >structure, > space group 15. > > Here is the atoms input file: > > ! This atoms input file was generated by Artemis 0.8.014 > ! Atoms written by and copyright (c) Bruce Ravel, 1998-2001 > title = ... > space = i 2/c 1 1 > a = 5.51120 b = 5.51120 c = 7.79410 > alpha = 90.0 beta = 90.740 gamma = 90.0 > core = Co1 edge = K rmax = 6.0 > !shift 0.25000 0.25000 0.25000 > atoms > ! elem x y z tag occ. > Fe 0.00000 0.00000 0.00000 Fe1 1.00000 > > If one calculates the Fe-Fe distance between the atom at (0,0,0) and >the > atom at (0, 0, 0.5), from application of the (x, -y, -z+0.5) lattice > translation, one finds a Fe-Fe distance of 3.9705. However, if one >runs the > above atoms input file, this Fe-Fe distance is not found. Instead, a >shift > vector of (0.25, 0.25, 0.25) is needed to get the correct Fe-Fe >distance. > Note, the i2/c space group is listed with only one origin in the > international tables. I determined the necessary shift vector from >trail and > error. It is still unclear to me why it was necessary to include a >shift > vector. So the best suggestion I have is that you can try including > different shift vectors in your own atoms.inp file and see if you >can get > agreement with the crystallography program that way. Since, as I >said, it > isn't clear to me why this fixed my problem, its hard to say if this >is the > same issue you are having, but it may be worth a try. > > It may also be worth while to calculate some atomic distances from >the > lattice positions given in the international tables, and see if >atoms or the > crystallography program is giving you the same thing. > >Finally, let me add on another question for the list here since it is > somewhat related. When one runs the above atoms.inp file with the >(0.25, > 0.25, 0.25) shift vector one finds four Fe1_1 atoms at 3.9701 and >two Fe_2 > atoms at 3.9705. When one then runs Feff, it combines these into a >single >Fe1_1 scattering path with N=6. Is there a command can be placed in >the Feff > input file to tell Feff not to combine identical paths like this? > > Best, > George > >

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Simulation of ion xanes spectra using feff9
by Aurora Clark 27 May '11

27 May '11

Hi; I hope you don¹t mind me posting a question about feff9 to this list, but the feff userlist is defunct. I am trying to learn feff9 by reproducing the work in a JPCA recent paper (JPCA 2011, 115, 2345). I have a calculated structure for U(H2O)8]4+ ion that is nearly identical to that of the paper and so I am using that structure. I have been able to run several test cases for feff9 and I think I have a reasonable understanding of the different cards in feff9 however there are definitely some particulars for these f-element ions that are eluding me. My primary question surround how to deal with ion charge 1. I have tried several options with the ion card, everything from the U having a charge of 4 and the O-atoms zero, to partial charges like 2 and 0.25. However, in each case I get errors that state: ION: Expert option, please read documentation carefully and check your results. ION: Expert option, please read documentation carefully and check your results. U4+-8h2o Now if I run the calculation with no charges on the atoms everything proceeds very smoothly. The manual states that charges typically should not exceed 1 for an atom but in a highly charged system what are you to do? Thank you; Aurora

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Re: [Ifeffit] more bugs in atoms?
by Gudrun Lisa Bovenkamp 26 May '11

26 May '11

Hi George, thanks for responding. I sure imported the same structural information into atoms and the crystal structure program. Lisa > > Hi Lisa, > > I'm not very familiar with PbSO4, so I'm not sure if I can help, but >your > email immediately brought some questions to mind. > >First, did you import the same information into atoms and the crystal > structure program? The way you worded your message made me think >that the > crystal structure program already "knew" the structure of PbSO4, in >which > case perhaps it is using a structure that is slightly different from >the one > you import into atoms. > > Second, what is the source of the structure data you are feeding >into atoms? > In my experience, errors and inconsistencies in the reporting of >structure > data in the literature can lead to unusual results in atoms. > > Best, > George > > >

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Re: [Ifeffit] Can Artemis Simulate a FT Spectrum?
by Palomino, Robert 19 May '11

19 May '11

Matt, Thank you. How would I go about making a theory sum? Would I have to do that in another graphing program or can it be done in Artemis? -----Original Message----- From: ifeffit-bounces(a)millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Thursday, May 19, 2011 1:00 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: Ifeffit Digest, Vol 99, Issue 17 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Can Artemis Simulate a FT spectrum? (Palomino, Robert) 2. Re: Can Artemis Simulate a FT spectrum? (Matt Newville) ---------------------------------------------------------------------- Message: 1 Date: Thu, 19 May 2011 11:38:45 -0400 From: "Palomino, Robert" <rpalomino(a)bnl.gov> To: <ifeffit(a)millenia.cars.aps.anl.gov> Subject: [Ifeffit] Can Artemis Simulate a FT spectrum? Message-ID: <B32CD18BE9D42745B75847F981879A3602051206(a)exchangemb3.bnl.gov> Content-Type: text/plain; charset="us-ascii" Hi, I was wondering if it was possible for Artemis to simulate a FT spectrum, I have a model and would like to visually see what the simple R-space spectrum would like so see if there are any similarites at all to my sample. I'm not sure if the reason it doesn't converge is because the signal level is too low or if it is the wrong model all together. Robert

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