Hi Rana, in the simple approximation E0 can be connected to electronic configuration of ion, in your situation (but I can only guess) ions can have different E0's (Fe, Mn), but in the first step I would keep one E0 value for each ion (one E0 for O, one for Fe, etc), especially that you are focused on first shell of oxygen
here we/I had a small discussion about E0 http://www.mail-archive.com/ifeffit@millenia.cars.aps.anl.gov/msg01745.html here you can find also something http://xafs.org/Tutorials?action=AttachFile&do=get&target=Newville_Intro.pdf best regards darek -----Wiadomość oryginalna----- Od: ifeffit-boun...@millenia.cars.aps.anl.gov w imieniu Jatinkumar Rana Wysłano: Śr 2010-07-28 09:40 Do: ifeffit@millenia.cars.aps.anl.gov Temat: Re: [Ifeffit] Ifeffit Digest, Vol 89, Issue 17 Hello Darek, Thank you so much for your reply. Yes, i can rely on model, we have performed reitveld refinement to get the crystallographic data. To my knowledge, there should not be any other phases. Your suggestion is quite right. Somehow, i have to constrain my parameters (to reduce the no. of parameters) and try to fit it. However, I would like to ask you following questions. I am confused about the term "Delta E0" what is the theoretical meaning of that in terms of photoelectron interactions ? If you have multiple atomic sites of absorbing atom, should "Delta E0" be same for all of them (assuming all absorbing atoms are at same oxidizing state) ? I am looking forward to your comments.. Best regards, Rana On 27.07.2010 19:00, ifeffit-requ...@millenia.cars.aps.anl.gov wrote: > Send Ifeffit mailing list submissions to > ifeffit@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-requ...@millenia.cars.aps.anl.gov > > You can reach the person managing the list at > ifeffit-ow...@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. updating Athena in Windows 7 (Monson, Todd) > 2. ODP: Ifeffit Digest, Vol 88, Issue 12 (Zajac, Dariusz A.) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 26 Jul 2010 14:39:00 -0600 > From: "Monson, Todd"<tmon...@sandia.gov> > To: "ifeffit@millenia.cars.aps.anl.gov" > <ifeffit@millenia.cars.aps.anl.gov> > Subject: [Ifeffit] updating Athena in Windows 7 > Message-ID: > <ac050ba7eac9a34e9a05bc31c3aa2e8b183c0d1...@es02snlnt.srn.sandia.gov> > Content-Type: text/plain; charset="us-ascii" > > On Saturday, while starting up Athena, I was informed that there was an > update to Athena available. I tried installing the update but failed. I am > afraid this is due to some user permission issue in windows 7. How can I try > to reinstall the update and ensure that it works? > Thanks, > Todd > > Todd Monson > Sandia National Labs > Nanomaterials Sciences > P.O. Box 5800, MS 1415 > Albuquerque, NM 87185-1415 > (505) 845-2129 > Fax: (505) 844-5470 > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL:<http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20100726/9267cfec/attachment.html> > > ------------------------------ > > Message: 2 > Date: Tue, 27 Jul 2010 17:47:36 +0200 > From: "Zajac, Dariusz A."<dariusz.za...@desy.de> > To: "XAFS Analysis using Ifeffit"<ifeffit@millenia.cars.aps.anl.gov> > Subject: [Ifeffit] ODP: Ifeffit Digest, Vol 88, Issue 12 > Message-ID: > <35e004ad6290a7438fca34bbf325f41601206...@adxv2.win.desy.de> > Content-Type: text/plain; charset="iso-8859-2" > > > Dear Rana, > sorry for really late response, but I was cut off from the internet for a > while... > if I understand correctly you created a model of the structure and you fit it > to the first shell (oxygen?), what is the expected difference between > different path? with my humble experience you can try to clarify following > problems: > - is your model really correct and cover all possible scenarios? > - are you sure that in your sample are no other (unwanted) phases? with Mn, > Fe it can happen... > - have you tried to increase the number of variables? (to free the fit from > boundaries) > > I am only thinking about it (with an examples at Fe site): > you have 4 positions for Fe and if there is a mixing between Fe and Mn sites > additional 3, it means maximally 7 sets of (e0, delr, and ss2 - N you can > probably estimate, calculate). that means you have more variables than > independent points. you should try, in the first approximation, to free the > delr parameter and keep others the same. I havent seen good example of > fitting such samples, but if you start from different points, and during > fitting you will minimize no. of variables with the same result (with the > same fit) should be ok. > good luck > darek > > -----Wiadomo?? oryginalna----- > Od: ifeffit-boun...@millenia.cars.aps.anl.gov w imieniu Jatinkumar Rana > Wys?ano: ?r 2010-06-16 12:57 > Do: ifeffit@millenia.cars.aps.anl.gov > Temat: Re: [Ifeffit] Ifeffit Digest, Vol 88, Issue 12 > > Dear Darek, > > Sorry for the late response. To fit the "first shell" the No.of > independent points and No.of variables which i use are as follows: > > I use deltaK=11, deltaR = 1.1 so No.of independent points are 8 and > No.of variables are 4 (i.e. N, e0, delr, and ss2) I set s02=0.9. > > Best regards, > Rana > > > > > > > > > > On 14.06.2010 19:00, ifeffit-requ...@millenia.cars.aps.anl.gov wrote: > >> Send Ifeffit mailing list submissions to >> ifeffit@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-requ...@millenia.cars.aps.anl.gov >> >> You can reach the person managing the list at >> ifeffit-ow...@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. XAFS fitting with multiple atomic sites of absorbing atom >> (Jatinkumar Rana) >> 2. ODP: XAFS fitting with multiple atomic sites of absorbing >> atom (Zajac, Dariusz A.) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Mon, 14 Jun 2010 12:00:27 +0200 >> From: Jatinkumar Rana<jatinkumar.r...@helmholtz-berlin.de> >> To: Ifeffit users<ifeffit@millenia.cars.aps.anl.gov> >> Subject: [Ifeffit] XAFS fitting with multiple atomic sites of >> absorbing atom >> Message-ID:<4c15fdbb.1050...@helmholtz-berlin.de> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> Dear users, >> >> I have measured XAFS spectra on Mn and Fe edge on my material. The >> material contains 3 different atomic positions for Mn and 4 different >> atomic positions for Fe. >> >> Initially, I tried fitting Fe-edge/Mn-edge spectra using indiviual Fe/Mn >> atomic position one-by-one (i.e. first take one Fe/Mn position, >> calculate Feff paths, consider certain paths to fit specific R-range, >> then take another Fe/Mn position and do the same) but the fit was not >> good visually and in terms of goodness of fit parameters. >> >> Then, i tried fitting Fe-edge/Mn-edge spectra, taking into account all >> Fe/Mn atomic position together i.e. I separately calulated Feff paths >> for each Fe/Mn atomic position and summed up related paths from each >> Feff calculation for fitting a specific R-range. (The assumption being, >> the experimental Fe-edge/Mn-edge XAFS spectra has varying contribution >> from all Fe/Mn atomic position in crystal structure). >> >> Anybody in the group could comment about my approach to fit such problem ? >> >> Is there any specific strategy to fit such problem ? >> >> I would be thankful if you could suggest some literature available on >> such problems. >> >> Thanks in advance. >> >> Best regards, >> Rana >> >> >> ------------------------------ >> >> Message: 2 >> Date: Mon, 14 Jun 2010 13:34:18 +0200 >> From: "Zajac, Dariusz A."<dariusz.za...@desy.de> >> To: "XAFS Analysis using Ifeffit"<ifeffit@millenia.cars.aps.anl.gov> >> Subject: [Ifeffit] ODP: XAFS fitting with multiple atomic sites of >> absorbing atom >> Message-ID: >> <35e004ad6290a7438fca34bbf325f41601206...@adxv2.win.desy.de> >> Content-Type: text/plain; charset="iso-8859-2" >> >> >> Dear Rana, >> could you specify how many independent data points and variables you have >> and you use for fitting? >> thnx >> darek >> >> -----Wiadomo?? oryginalna----- >> Od: ifeffit-boun...@millenia.cars.aps.anl.gov w imieniu Jatinkumar Rana >> Wys?ano: Pn 2010-06-14 12:00 >> Do: Ifeffit users >> Temat: [Ifeffit] XAFS fitting with multiple atomic sites of absorbing atom >> >> Dear users, >> >> I have measured XAFS spectra on Mn and Fe edge on my material. The >> material contains 3 different atomic positions for Mn and 4 different >> atomic positions for Fe. >> >> Initially, I tried fitting Fe-edge/Mn-edge spectra using indiviual Fe/Mn >> atomic position one-by-one (i.e. first take one Fe/Mn position, >> calculate Feff paths, consider certain paths to fit specific R-range, >> then take another Fe/Mn position and do the same) but the fit was not >> good visually and in terms of goodness of fit parameters. >> >> Then, i tried fitting Fe-edge/Mn-edge spectra, taking into account all >> Fe/Mn atomic position together i.e. I separately calulated Feff paths >> for each Fe/Mn atomic position and summed up related paths from each >> Feff calculation for fitting a specific R-range. (The assumption being, >> the experimental Fe-edge/Mn-edge XAFS spectra has varying contribution >> from all Fe/Mn atomic position in crystal structure). >> >> Anybody in the group could comment about my approach to fit such problem ? >> >> Is there any specific strategy to fit such problem ? >> >> I would be thankful if you could suggest some literature available on >> such problems. >> >> Thanks in advance. >> >> Best regards, >> Rana >> _______________________________________________ >> Ifeffit mailing list >> Ifeffit@millenia.cars.aps.anl.gov >> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit >> >> >> >> ------------------------------ >> >> _______________________________________________ >> Ifeffit mailing list >> Ifeffit@millenia.cars.aps.anl.gov >> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit >> >> >> End of Ifeffit Digest, Vol 88, Issue 12 >> *************************************** >> >> >> >> > _______________________________________________ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > > > > ------------------------------ > > _______________________________________________ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > > > End of Ifeffit Digest, Vol 89, Issue 17 > *************************************** > > > _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
