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

S02 and k_min
by Michael Morrill 02 Dec '12

02 Dec '12

Hello everyone, I am currently performing a simple curve fit on bulk MoS2 using an atoms file for crystalline MoS2. I've found that increasing k_min on my fit (e.g. from 2 to 4) improves the quality of the fit (R-factor from 0.028 to 0.009), but also increases S02. If I use a large enough k_min (but not so large I run out of data), S02 gets as high as 1.2 +/- 0.05. This trend is observable for single and multiple k-weight fittings. While I understand that S02>1.0 does not necessarily invalidate the fit, I am not sure how to justify which parameter values are the best seeing that "0.8<S02<1.0" is often one of the justifications that everything "is reasonable." Ultimately, I want to assume the S02 is chemically transferrable and use it for curve fits on metal oxide supported MoS2. Any direction on the mater would be greatly appreciated. Thank you, Mike Morrill GaTech CHBE

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Help to run Demeter on Windows XP (So. Muru)
by Andrei Shiryaev 30 Nov '12

30 Nov '12

Dear All, I have a similar problem running Demeter on Windows 7 64 bit. It simply makes nothing. I remember that several years ago there was a problem to run IFEFFIT on XP windows machines which were operating under non-unicode settings (in those cases it was Brazilian (i.e. Portugese) and Russian versions). Bruce had solved the problem using another compilation of Perl, if I am correct. Is is possible that the same "non-unicode" problem persists in Demeter? All the best, A.Shiryaev

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Help to run Demeter on Windows XP
by So. Muru 27 Nov '12

27 Nov '12

Dear all, greetings from Murugesan, recently I downloaded the latest version of Demeter for windows and installed it on my windows xp (32bit) environment. I try to run the programs by shortcuts in the desktop, but the programs didn't run. what was the problem, kindly give your suggestions to run the Demeter package successfully on windows xp environment. with thanks and regards S Murugesan -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dr S Murugesan Kalpakkam, Tamil Nadu India Email : muruges(a)gmail.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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Re: [Ifeffit] FOLP
by Joshua Kas 27 Nov '12

27 Nov '12

Hi Enyuan, It is very strange that FOLP 1.3 is causing the code to take longer. There really should be almost no difference in timing between different values of FOLP. This has to be a bug. Would you mind sending your input file? As for the CRITERIA card, this effects the filtering of the path expansion. The path expansion should only be used for EXAFS calculations, which is why the CRITERIA card is greyed out for XANES calculations (which use full multiple scattering). If you really want to run XANES with path expansion, you can still do that using the text based input and running the code from the command line. If you don't know how to do this, I can explain. Just let me know what operating system you are using. Cheers, Josh > > Hi Joshua, > > Thank you for your comment. Like you said, I tried FOLP with value from 1 > to 1.3 and it didn't change the calculated spectrum much. It's very > time-consuming when FOLP reached 1.3, taking more than 3 hours to finish > the calculation on my laptop. On using 0.8 for hydrogen, actually I'm going > to calculated a sample with lots of Li in it. Do you suggest using a > similarly small number of FOLP for Li, in an analogy to H? The other thing > I want to ask is the CRITERIA card in Feff9. It seemed that once I asked > the program to calculate XANES, the CRITERIA card in the software cannot be > checked. It can only be checked if I selected EXAFS calculation mode. Is > there any way to solve this? thanks again for all your answers. > > Enyuan > > > On Mon, Nov 26, 2012 at 5:33 PM, > <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: FOLP card (Joshua Kas) > > 2. Question on Glitch in FEFF for Ru EXAFS measurements > > (Dooshaye Moonshiram) > > 3. Re: Question on Glitch in FEFF for Ru EXAFS measurements > > (Bruce Ravel) > > 4. Re: Question on Glitch in FEFF for Ru EXAFS measurements > > (Bobrik, Michael) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Mon, 26 Nov 2012 10:56:19 -0800 > > From: Joshua Kas <joshua.j.kas(a)gmail.com> > > To: ifeffit(a)millenia.cars.aps.anl.gov > > Subject: Re: [Ifeffit] FOLP card > > Message-ID: > > < > > CAHuhYRkW5R6iSLjSc03aNnfVRmX+YWvUiNB4HDF7CDEJLNNSjw(a)mail.gmail.com> > > Content-Type: text/plain; charset="iso-8859-1" > > > > Hi Enyuan, > > I don't really know a rule of thumb for ionic bond v.s. covalent bond, > but > > by default, the FEFF code will automatically choose reasonable muffin > tins > > in most cases, and most of the time it overlaps them by ~15%, i.e. FOLP > > 1.15. In many cases, the overlap doesn't change the structure in the > XANES > > a lot until you get far from FOLP 1.0. However, there are some special > > cases. For example, we have found that using FOLP 0.8 for hydrogen atoms > > seem's to work reasonably well in the XANES. This is because of the short > > bond lengths of H. In addition, there are cases where one atom is fairly > > isolated from the others, i.e., cage like structures, where FEFF can't > > overlap the potentials, and setting FOLP to something smaller than 1.0 is > > essential to make the code run. I would start by letting the code choose > > the muffin tins automatically, then change them and see how the results > > change. If the changes in the XANES are small, you probably don't have to > > worry about FOLP. Otherwise, this is probably a limitation of the > spherical > > muffin tin potential. The best thing to do in that case, is to compare > the > > DOS (LDOS) with a calculation from a full potential electronic structure > > code, i.e., WIEN2K, ABINIT, QUANTUM ESPRESSO, etc. > > This can give you confidence in the FEFF calculation, or lead you to the > > best values for FOLP. You could also use the FOLP values to get the best > > comparison to experiment, but in some cases you may be fitting many-body > > effects, which can lead you to the wrong conclusions about your system. > > Cheers, > > Josh Kas > > > > On Mon, Nov 26, 2012 at 7:53 AM, > > <ifeffit-request(a)millenia.cars.aps.anl.gov>wrote: > > > > > Re: > >

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Re: [Ifeffit] Ifeffit Digest, Vol 117, Issue 24
by Enyuan Hu 27 Nov '12

27 Nov '12

Hi Joshua, Thank you for your comment. Like you said, I tried FOLP with value from 1 to 1.3 and it didn't change the calculated spectrum much. It's very time-consuming when FOLP reached 1.3, taking more than 3 hours to finish the calculation on my laptop. On using 0.8 for hydrogen, actually I'm going to calculated a sample with lots of Li in it. Do you suggest using a similarly small number of FOLP for Li, in an analogy to H? The other thing I want to ask is the CRITERIA card in Feff9. It seemed that once I asked the program to calculate XANES, the CRITERIA card in the software cannot be checked. It can only be checked if I selected EXAFS calculation mode. Is there any way to solve this? thanks again for all your answers. Enyuan On Mon, Nov 26, 2012 at 5:33 PM, <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: FOLP card (Joshua Kas) > 2. Question on Glitch in FEFF for Ru EXAFS measurements > (Dooshaye Moonshiram) > 3. Re: Question on Glitch in FEFF for Ru EXAFS measurements > (Bruce Ravel) > 4. Re: Question on Glitch in FEFF for Ru EXAFS measurements > (Bobrik, Michael) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 26 Nov 2012 10:56:19 -0800 > From: Joshua Kas <joshua.j.kas(a)gmail.com> > To: ifeffit(a)millenia.cars.aps.anl.gov > Subject: Re: [Ifeffit] FOLP card > Message-ID: > < > CAHuhYRkW5R6iSLjSc03aNnfVRmX+YWvUiNB4HDF7CDEJLNNSjw(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Enyuan, > I don't really know a rule of thumb for ionic bond v.s. covalent bond, but > by default, the FEFF code will automatically choose reasonable muffin tins > in most cases, and most of the time it overlaps them by ~15%, i.e. FOLP > 1.15. In many cases, the overlap doesn't change the structure in the XANES > a lot until you get far from FOLP 1.0. However, there are some special > cases. For example, we have found that using FOLP 0.8 for hydrogen atoms > seem's to work reasonably well in the XANES. This is because of the short > bond lengths of H. In addition, there are cases where one atom is fairly > isolated from the others, i.e., cage like structures, where FEFF can't > overlap the potentials, and setting FOLP to something smaller than 1.0 is > essential to make the code run. I would start by letting the code choose > the muffin tins automatically, then change them and see how the results > change. If the changes in the XANES are small, you probably don't have to > worry about FOLP. Otherwise, this is probably a limitation of the spherical > muffin tin potential. The best thing to do in that case, is to compare the > DOS (LDOS) with a calculation from a full potential electronic structure > code, i.e., WIEN2K, ABINIT, QUANTUM ESPRESSO, etc. > This can give you confidence in the FEFF calculation, or lead you to the > best values for FOLP. You could also use the FOLP values to get the best > comparison to experiment, but in some cases you may be fitting many-body > effects, which can lead you to the wrong conclusions about your system. > Cheers, > Josh Kas > > On Mon, Nov 26, 2012 at 7:53 AM, > <ifeffit-request(a)millenia.cars.aps.anl.gov>wrote: > > > Re: >

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Question on Glitch in FEFF for Ru EXAFS measurements
by Dooshaye Moonshiram 27 Nov '12

27 Nov '12

Dear Bruce, I recently collected EXAFS data on the *Tris(bipyridine)ruthenium(II) dichloride Ru 2 compound-photosensitizer in solution form. In order to compare EXAFS data to XRD data, I uploaded the XRD coordinates of this crystal structure from cambridge database in a FEFF calculation page in ARTEMIS. I ran FEFF on the x,y and z coordinates of this standard compound in Artemis and summed all paths to compare with my experimental data(collected in solution form in fluorescence mode)* *I have 2 problems* *1) I found a glitch when running FEFF in ARTEMIS. In order to compare XRD coordinates to EXAFS data, I upload the XRD coordinates in a FEFF calculation page, run FEFF and sum all paths. Now* *a) **f I upload the XRD coordinates in a FEFF calculation page without having the EXAFS artemis file present, I get different fits compared to* *b) if I first upload the EXAFS experimental file and then run FEFF on the XRD cartesian coordinates. It seems that **the sum of all paths from the FEFF calculation page tend to mimic the experimental EXAFS file which has first been uploaded and is not a true presentation of how the FT should be.* * * *-Please let me know if this is unclear and I can send you my EXAFS file as well as the XRD coordinates which I obtained from Cambridge structural databse* * * *2) Another problem which I have with my EXAFS data is that I have a peak at 2.5 Angstrom which does not match XRD coordinates and is not present if I run FEFF on XRD coordinates only(true comparison as I don't add the the experimental file in Artemis). Could this peak be due to the Ru standard somehow? All measurements were done in fluorescence mode (F/Io) at 20 K in cryostat using a germanium detector. I simultaneously collected EXAFS measurements on Ru metal standard between Iref and IT ionization chambers.* * * *Thank you for your help,* *Sincerely* *Best Regards* *Dooshaye Moonshiram*

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Re: [Ifeffit] Ifeffit Digest, Vol 117, Issue 13
by Zack Gainsforth 26 Nov '12

26 Nov '12

Kyler, you and Tsu-Chien are terrific! iXAFS is working for me again! Cheers, Zack Gainsforth Space Sciences Laboratory, UC Berkeley 7 Gauss Way Berkeley, CA 94720 510-642-9733 zackg(a)ssl.berkeley.edu On Nov 15, 2012, at 10:00 AM, 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: Launching Athena on Mountain Lion (Mac OS 10.8) (Kyler Carroll) ---------------------------------------------------------------------- Message: 1 Date: Thu, 15 Nov 2012 09:32:34 -0800 From: Kyler Carroll <kyler.carroll(a)gmail.com> To: ifeffit(a)millenia.cars.aps.anl.gov Subject: Re: [Ifeffit] Launching Athena on Mountain Lion (Mac OS 10.8) Message-ID: <CAN+rEib3FNvmTE0x8BPgCBN2TRytRE+1CG2aN6A=mEEWxS6NcA(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" 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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Help: some operation using Athena and Artemis
by Bingjie Ouyang 26 Nov '12

26 Nov '12

Hi, I just joined the mailing list recommended by a friend, I hear this is a really good place to communicate and learn. So I'm here, actually I need help for some basic questions on Iffeffit software: 1, In Athena, how to make a fourier transform draft? 2, In Artemis, since I was told that each shell in R-space can be fitted separatly, is it OK to fit each shell in the R-range respectively, and then join up the fitted curve and just ignore the not match part in other R-ranges? And can a shell be comprised of several different paths (like Fe-O and Fe-S)? Thank you. Best wishes, Bingjie -- Bingjie Ouyang School of Earth Sciences and Engineering Nanjing University 22nd Hankou Road, Nanjing, Jiangsu, 210093 P. R. China Email: jessicaoy89(a)gmail.com

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Re: [Ifeffit] FOLP card
by Joshua Kas 26 Nov '12

26 Nov '12

Hi Enyuan, I don't really know a rule of thumb for ionic bond v.s. covalent bond, but by default, the FEFF code will automatically choose reasonable muffin tins in most cases, and most of the time it overlaps them by ~15%, i.e. FOLP 1.15. In many cases, the overlap doesn't change the structure in the XANES a lot until you get far from FOLP 1.0. However, there are some special cases. For example, we have found that using FOLP 0.8 for hydrogen atoms seem's to work reasonably well in the XANES. This is because of the short bond lengths of H. In addition, there are cases where one atom is fairly isolated from the others, i.e., cage like structures, where FEFF can't overlap the potentials, and setting FOLP to something smaller than 1.0 is essential to make the code run. I would start by letting the code choose the muffin tins automatically, then change them and see how the results change. If the changes in the XANES are small, you probably don't have to worry about FOLP. Otherwise, this is probably a limitation of the spherical muffin tin potential. The best thing to do in that case, is to compare the DOS (LDOS) with a calculation from a full potential electronic structure code, i.e., WIEN2K, ABINIT, QUANTUM ESPRESSO, etc. This can give you confidence in the FEFF calculation, or lead you to the best values for FOLP. You could also use the FOLP values to get the best comparison to experiment, but in some cases you may be fitting many-body effects, which can lead you to the wrong conclusions about your system. Cheers, Josh Kas On Mon, Nov 26, 2012 at 7:53 AM, <ifeffit-request(a)millenia.cars.aps.anl.gov>wrote: > Re:

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Plot multiple fits in (D)Artemis and statistical errors
by Nilmar Camilo 26 Nov '12

26 Nov '12

Dear Bruce, I am new in the list and really don't know if the points raised below were already discussed. In the (D)Artemis (Demeter version 0.9.13) how may I: - Plot different fits with the experimental data (to visually compare the results) - I don't know if this is a (new) bug of the program but when I try to restore a fit the program closes. In the log file the following line is written: "Can't use an undefined value as a HASH reference at C:/Strawberry/perl/site/lib/Demeter/Fit.pm line 1558." Obs.: I am running Demeter in Windows 7 (Pro). Another problem is related to the statistical errors when constraining the S0^2 parameter to float between two limits. The program doesn't return the error for all others parameters (but just zero as the error value) as you can see below: guess parameters: amp = 0.79284158 # +/- 0.00000000 [0.95] enot = 5.29826510 # +/- 0.00000000 [0] delrIn11 = 0.00235278 # +/- 0.00000000 [0] ssIn11 = 0.00155959 # +/- 0.00000000 [0.00300] delrCe1 = -0.00231455 # +/- 0.00000000 [0] ssCe1 = 0.00192778 # +/- 0.00000000 [0.00300] delrIn11In11 = 0.02070081 # +/- 0.00000000 [0] delrIr1 = -0.00435502 # +/- 0.00000000 [0] ssIr1 = 0.00386517 # +/- 0.00000000 [0.00300] delrIn31 = 0.00648507 # +/- 0.00000000 [0] ssIn31 = 0.00669602 # +/- 0.00000000 [0.00300] delrIn12 = 0.00255704 # +/- 0.00000000 [0] ssIn12 = 0.00305432 # +/- 0.00000000 [0.00300] def parameters: b = 0.80000000 # [min(max(0.8,amp),1.0)] Thanks so much in advance. Nilmar

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