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

a few words...
by Bruce Ravel 18 Jun '04

18 Jun '04

Hi folks, This is just a quick note to let everyone know that I have read all of the traffic on the mailing list from the last two weeks. Clearly there are some serious issues with the current release of artemis that need my attention. I am still in the middle of a very busy period and won't have much time to devote to the codes for a couple more weeks, but I wanted everyone to know that I have read about the problems and will work on solutions just as soon as I get a chance. Thanks to those who commented for your input. As I have said many times before, the codes are only usable because of the contributions of their users. It seems that most of the non-bug report traffic was answered to some extent. I probably will not respond to any of the mail from the last two weeks, so if anyone posted a question for me that didn't get answered to your satisfaction, I would recommend posting it again. I also wanted to comment on a couple of things that made me laugh out loud. One was was Paul's comment to Chris Derr asking him to inform the list of the answer once he gets EXAFS all figured out. (Is it 42?) The other was when Doug Pease (sorry for picking on you Doug, but this *was* funny) refered to Shelly Kelly as Mary Shelly. Mary Shelley, of course, was the author of Frankenstein. I would say that it is unfair to burden Shelly with the responsibility of creating a Frankenstein monster. That would be me or Matt, I think, depending on whether the interior part or the exterior part seems more monstrous to you ;-) B -- Bruce Ravel ----------------------------------- ravel(a)phys.washington.edu Code 6134, Building 3, Room 405 Naval Research Laboratory phone: (1) 202 767 2268 Washington DC 20375, USA fax: (1) 202 767 4642 NRL Synchrotron Radiation Consortium (NRL-SRC) Beamlines X11a, X11b, X23b National Synchrotron Light Source Brookhaven National Laboratory, Upton, NY 11973 My homepage: http://feff.phys.washington.edu/~ravel EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/

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Fwd: Alignment!
by Bruce Ravel 18 Jun '04

18 Jun '04

Hi folks, I received this (rather vague) question this morning and thought I would forward it along to the list for discussion. A couple of FAQ entries seem relevant: http://cars9.uchicago.edu/cgi-bin/ifeffit/faqwiz?req=all#5.6 and http://cars9.uchicago.edu/cgi-bin/ifeffit/faqwiz?req=all#5.7 Perhaps someone could write a FAQ entry on the topic of data alignment... B ---------- Forwarded Message ---------- Subject: Alignment! Date: Friday 18 June 2004 10:20 am From: Nasser Afify <n_afify(a)science.unitn.it> To: ravel(a)phys.washington.edu Dear Prof., I need to align my fluorescence spectra to the one of the reference before the extraction of the signals, but it is too difficult to align, what is the best way for alignment and what is the best choice of E0 in the case of noisy data. thank you for your time best regards, Yours Nasser ------------------------------------------------------- -- Bruce Ravel ----------------------------------- ravel(a)phys.washington.edu Code 6134, Building 3, Room 405 Naval Research Laboratory phone: (1) 202 767 2268 Washington DC 20375, USA fax: (1) 202 767 4642 NRL Synchrotron Radiation Consortium (NRL-SRC) Beamlines X11a, X11b, X23b National Synchrotron Light Source Brookhaven National Laboratory, Upton, NY 11973 My homepage: http://feff.phys.washington.edu/~ravel EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/

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Re: A very quick question
by Barton, David (DG) 18 Jun '04

18 Jun '04

On Thursday 17 June 2004 03:17 pm, Ahmed M Shahin wrote: AM> Hello, I would like to ask a very quick question and I would AM> appreciate if someone can help me. While running XANES fitting AM> for mixed valence state metals such as cerium (3/4), should I use AM> two arctangent functions with selected group of Lorentzian AM> functions or I have to use only one arctangent function with a AM> group of Gaussian functions? I would appreciate if someone give AM> some advice. Yours, Ahmed I have used the XANES peak fitting option some in Athena and would concur with Bruce's suggestions that peak fitting needs to be handled in a *consistent* manner to be useful. With that said, I appreciated Bruce adding the feature to be able to fit multiple arctangents because it can help tease out the relative ratios of mixed valence state metals. However, one must be careful to not overinterpret these fits because of the sensitivity of the XANES edges to coordination changes as well as oxidation state. With the appropriate set of standards this fitting can be a useful tool especially when the data quality does not permit a full blown EXAFS analysis. In regards to the other peak shapes (Lorentzian or Gaussians)....use what fits best. This fitting is just a tool to help describe your datasets and is not a fundamental approach to XANES interpretation. One other suggestion, be patient with the fitting and play around. Try multiple initial guesses, don't let all variable float in the initial fit, consider fitting the energy first and then fix it and fit the other variables. Once you get a good fit, use this solution as the initial guesses for all your other datasets. And....one other feature request for Bruce for Athena version 2.3. It would be nice if we could put constraints on each of the fitting variables. This would help prevent fits where the variables quickly spin off into meaningless territory. Of course, implemenation of this feature could get complex given the number of variables to be fit. An easier implemenation of constraints would be a checkbox and a % deviation field that would let the variables chosen float within that %deviation. Dave _________________________________ David Barton The Dow Chemical Company Catalysis R&D 1776 Building Midland, MI 48674 USA Email: dgbarton(a)dow.com

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Regarding XANES spectra of Manganese oxides
by Grant Bunker 17 Jun '04

17 Jun '04

This is in response to Prof. Gang Ho Lee's question. There is indeed a spinel form of Mn2O3 which is isostructural with Mn3O4, except (as I recall from twenty years ago) that the +2 and +3 ion populations are reversed (2/3 of the ions are in octahedral sites, and 1/3 in tetrahedral). So even though the average charge state is changed, the structure isn't. The XANES and XRD are virtually the same because the structures are virtually the same. grant bunker On Thu, 17 Jun 2004 ifeffit-request(a)millenia.cars.aps.anl.gov wrote: > 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: a few words... (scalvin(a)slc.edu) > 2. A very quick question (Ahmed M Shahin) > 3. Re: A very quick question (Bruce Ravel) > 4. Reagrding Xanes spectra of manganese oxides (Gang Ho Lee) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Jun 2004 14:01:28 -0400 (EDT) > From: scalvin(a)slc.edu > Subject: Re: [Ifeffit] a few words... > To: ravel(a)phys.washington.edu, "XAFS Analysis using Ifeffit" > <ifeffit(a)millenia.cars.aps.anl.gov> > Message-ID: <2823.138.110.111.207.1087495288.squirrel(a)mail.slc.edu> > Content-Type: text/plain;charset=iso-8859-1 > > Bruce said: > > > I also wanted to comment on a couple of things that made me laugh out > > loud. One was was Paul's comment to Chris Derr asking him to inform > > the list of the answer once he gets EXAFS all figured out. (Is it > > 42?) > > > > Bruce! I'm shocked at you! Everyone knows that legitimate EXAFS results > must always be reported with the uncertainty; the answer is actually 42 > +/- pi. > > --Scott Calvin > Sarah Lawrence College > > > ------------------------------ > > Message: 2 > Date: Thu, 17 Jun 2004 14:17:38 -0500 > From: "Ahmed M Shahin" <shahin(a)umr.edu> > Subject: [Ifeffit] A very quick question > To: <Ifeffit(a)millenia.cars.aps.anl.gov> > Message-ID: <001a01c4549f$c0ece3a0$fc689783(a)chem.umr.edu> > Content-Type: text/plain; charset="iso-8859-1" > > Hello, > I would like to ask a very quick question and I would appreciate if someone can help me. > While running XANES fitting for mixed valence state metals such as cerium (3/4), should I use two arctangent functions with selected group of Lorentzian functions or I have to use only one arctangent function with a group of Gaussian functions? > I would appreciate if someone give some advice. > Yours, > Ahmed > >

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Reagrding Xanes spectra of manganese oxides
by Gang Ho Lee 17 Jun '04

17 Jun '04

Dear Sirs I am writing to you because we are not familiar with xanes. We took xanes spectra of both sample (synthesized by us and we think it as gamma-Mn2O3 ) and Mn3O4 (reference) to make sure that we synthesized gamma-Mn2O3 nanoparticles. The particle diameters ranged from 10 to 15 nm. By using XRD pattern, the structure of sample was determined to be tetragonal with lattice constants of a=5.79 A and c=9.4 A, similar to Mn3O4. From the XRD patterns, we can not distinguish between gamma-Mn2O3 and Mn3O4 because both show nearly identical XRD patterns (JACS 72, 856 (1950)). We attached a data file. Could you please tell us whether the sample is gamma-Mn2O3 nanoparticles or not. Sincerely, Prof. Gang Ho Lee Department of Chemistry College of Natural Sciences Kyungpook National University Taegu 702-701, South Korea tel: 001-82-53-950-5340 fax: 001-82-53-950-6330 e-mail: ghlee(a)bh.knu.ac.kr

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A very quick question
by Ahmed M Shahin 17 Jun '04

17 Jun '04

Hello, I would like to ask a very quick question and I would appreciate if someone can help me. While running XANES fitting for mixed valence state metals such as cerium (3/4), should I use two arctangent functions with selected group of Lorentzian functions or I have to use only one arctangent function with a group of Gaussian functions? I would appreciate if someone give some advice. Yours, Ahmed

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Artemis: Error in laoding additional FEFF paths?
by Carlo U. Segre 17 Jun '04

17 Jun '04

Hello All: One of my students is just trying Scott's ZnO tutorial and we are finding a consistent problem when trying to work with the third project file. When we get to the point of adding an additional path, (feff0011.dat), artemis crashes with the following message: --------------------------------- The following message was trapped by Artemis: Artemis0.7.006warn/home/segre/.horae/stash/ARTEMIS.TRAPCODE(0x9652e54)/home/segre/.horae/stash/artemis.project.2/ at /usr/bin/artemis line 1562 main::__ANON__('Use of uninitialized value in string eq at /usr/bin/artemis l...') called at /usr/bin/artemis line 7313 main::read_feff('^^') called at /usr/lib/perl5/Tk.pm line 225 eval {...} called at /usr/lib/perl5/Tk.pm line 225 Tk::__ANON__('Tk::Menu=HASH(0x974a060)', 'active') called at /usr/lib/perl5/Tk/Menu.pm line 531 Tk::Menu::Invoke('Tk::Menu=HASH(0x974a060)', 1) called at /usr/lib/perl5/Tk.pm line 347 eval {...} called at /usr/lib/perl5/Tk.pm line 347 Tk::MainLoop() called at /usr/bin/artemis line 1707 -------------------------------- This is happening on all of my Linux machines. They are using my Debian packages and so I have not tried with the tarball installation. Has anyone else had this problem? I hesitate to report it as a bug until it is confirmed. In a previous version of horae, it worked fine. Carlo -- Carlo U. Segre -- Professor of Physics Associate Dean for Special Projects, Graduate College Illinois Institute of Technology Voice: 312.567.3498 Fax: 312.567.3494 Carlo.Segre(a)iit.edu http://www.iit.edu/~segre

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Re: [Ifeffit] Iffeffit1.5.2a compilation troubles
by Stefano Ciurli 16 Jun '04

16 Jun '04

Hello folks, I said earlier: "Apparently, I need to restart the PC any time that somethig goes wrong with aquaterm" No, the problem is really with the ZnO tutorial .apj files. I get aquaterm starting when I open a Cu.chi file, but I do not get it to open when I try to read the ZnO1.apj file. I think this is due to some bug in horae, which makes the programs not really good at managing project files. I think Bruce said something like that some time ago. Stefano -- ____________________________________________ Stefano Ciurli Professor of Chemistry Department of Agro-Environmental Science and Technology University of Bologna Viale Giuseppe Fanin, 40 I-40127 Bologna Italy Phone: +39-051-209-6204 Fax: +39-051-209-6203 "Fatti non foste a viver come bruti, ma per seguir virtute e canoscenza" Dante Alighieri - Inferno - Canto XXVI

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Re: [Ifeffit] Iffeffit1.5.2a compilation troubles
by Stefano Ciurli 16 Jun '04

16 Jun '04

Hello folks, following the "lost" message from yesterday, and in order to solve the apparent bug that aquaterm does not start automatically etc etc, I reinstalled 1.2.5a using the binary installer AND, this time, restarted the computer (the same old trick). This time aquaterm opens again.... Then, after running the horae_update --force command, aquaterm does not open automatically. BUT, if I restart again the PC, the aquaterm opens. Apparently, I need to restart the PC any time that somethig goes wrong with aquaterm. Stefano -- ____________________________________________ Stefano Ciurli Professor of Chemistry Department of Agro-Environmental Science and Technology University of Bologna Viale Giuseppe Fanin, 40 I-40127 Bologna Italy Phone: +39-051-209-6204 Fax: +39-051-209-6203 "Fatti non foste a viver come bruti, ma per seguir virtute e canoscenza" Dante Alighieri - Inferno - Canto XXVI

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Re: [Ifeffit] Artemis: Error in laoding additional FEFF paths?
by Stefano Ciurli 15 Jun '04

15 Jun '04

Matt, as to the following question: QUESTION: I do not seem to have, in tcsh, the command "configure" I think I solved this one by entering the /Users/stefano/Tk-804.027/ifeffit-1.2.5 directory I am proceeding with the resto of the indicated protocol, so far not caring about the downloading directory (I am using my home directory right now). Please let me know whether I can change the Tk-804.027 directory from my home directory to where it is more right to move it (which I do not know). Thanks, Stefano -- ____________________________________________ Stefano Ciurli Professor of Chemistry Department of Agro-Environmental Science and Technology University of Bologna Viale Giuseppe Fanin, 40 I-40127 Bologna Italy Phone: +39-051-209-6204 Fax: +39-051-209-6203 "Fatti non foste a viver come bruti, ma per seguir virtute e canoscenza" Dante Alighieri - Inferno - Canto XXVI

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