Re: [Ifeffit] problem with E0 (enot) parameters

As Anatoly mentioned, feff6 overestimates e0 (the Fermi energy). This is at least partially due to the use of overlapped atomic potential. The problem is fixed when the self-consistent potentials are used in feff8. If no self-consistency is used, I believe feff6 and feff8 give very similar results. Josh

From: "Frenkel, Anatoly" Subject: Re: [Ifeffit] problem with E0 (enot) parameters To: "XAFS Analysis using Ifeffit" , "XAFS Analysis using Ifeffit" Message-ID: Content-Type: text/plain; charset="iso-8859-1"

Just a comment, to add some sanity in this discussion:

FEFF6 is overestimating delta E0 for Pt and a few other metals. I forgot the reason but it could be the cause of a problem. I think FEFF8 is doing a better job. Fortunately - and it was checked - no other problems occur, just E0 values change, when one usees FEFF8 instead of FEFF6 in most cases. > Anatoly

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From: ifeffit-bounces@millenia.cars.aps.anl.gov on behalf of Kropf, Arthur Jeremy Sent: Fri 6/19/2009 3:41 PM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] problem with E0 (enot) parameters

With the very strong white lines at the L3 edges of oxidized Pt, W, Ir, etc., there is no reason to assume that Eo is on the lower energy side of the peak.

Jeremy Kropf

...

-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of Zajac, Dariusz A. Sent: Friday, June 19, 2009 9:45 AM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] problem with E0 (enot) parameters

Hi Scott, I am afraid that E0 jumps over the edge - see bmp's in the attachment (files with enot_12 means E0=12...). Hovewer 12 eV is still less than k=3 (the starting k value). Can it influence? I did also once more fit with R from 1.7 to 4A. Fits of first 2 peaks are identical - you can see in the attachment too... I hope you and anyone from the mailing list don't mind that I am attaching so many files...

cheers darek

...

-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of Scott Calvin Sent: Friday, June 19, 2009 2:49 PM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] problem with E0 (enot) parameters

Hi Darek,

OK, so if the K, H, and O don't affect the fit much for the C and N, and the K, H, and O are returning nonsensical values, then a logical possibility is that the E0's for C and N are correct. If you add 12 eV to the E0 you chose in Athena, where in the spectrum does it fall? Is it still before the white line? If so, it seems to me you don't have a problem. If not, then we have to ponder further.

--Scott Calvin Sarah Lawrence College

On Jun 19, 2009, at 8:28 AM, Zajac, Dariusz A. wrote:

...

Hi Scott, look also at H and O, but for me and for this fit important are only W-C and W-C-N bondings. This sample is an reference sample for other cyano-brigded networks. So you suggest to focuse on K ions? how can it help with first 2 peaks? K is at ~5A. I have analysed in larger R space only to see how the spectrum behave. contribution from K, O etc. at k highers than 5A is for me too low to analyse it resonable for such compound. I have attached in the previus post the last version of results. Anyway, enots for C and N do not change if I am enlarging R region (when I am including next paths, also for K). about material I am quite sure ;) and crystal structure is from literature

in the attachment you will find bmp file of the fit: data, fit, bkg and K path. fitting ranges k(3-15) R(1.7-6) dk 2 dr 0.5, phase correction - first C

cheers darek

_______________________________________________ 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

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Message: 3 Date: Sat, 20 Jun 2009 10:37:09 +0200 From: "Zajac, Dariusz A." Subject: [Ifeffit] ODP: problem with E0 (enot) parameters To: "XAFS Analysis using Ifeffit" Message-ID: <35E004AD6290A7438FCA34BBF325F4160C57F8@ADXV2.win.desy.de> Content-Type: text/plain; charset="iso-8859-2"

Dear Jeremy, thanks for your reply. This fits to my results and to my "feeling", but is any physical meaning behind it? cheers darek

-----Wiadomo?? oryginalna----- Od: ifeffit-bounces@millenia.cars.aps.anl.gov w imieniu Kropf, Arthur Jeremy Wys?ano: Pt 2009-06-19 21:41 Do: XAFS Analysis using Ifeffit Temat: Re: [Ifeffit] problem with E0 (enot) parameters

With the very strong white lines at the L3 edges of oxidized Pt, W, Ir, etc., there is no reason to assume that Eo is on the lower energy side of the peak.

Jeremy Kropf

...

-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of Zajac, Dariusz A. Sent: Friday, June 19, 2009 9:45 AM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] problem with E0 (enot) parameters

Hi Scott, I am afraid that E0 jumps over the edge - see bmp's in the attachment (files with enot_12 means E0=12...). Hovewer 12 eV is still less than k=3 (the starting k value). Can it influence? I did also once more fit with R from 1.7 to 4A. Fits of first 2 peaks are identical - you can see in the attachment too... I hope you and anyone from the mailing list don't mind that I am attaching so many files...

cheers darek

...

-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of Scott Calvin Sent: Friday, June 19, 2009 2:49 PM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] problem with E0 (enot) parameters

Hi Darek,

OK, so if the K, H, and O don't affect the fit much for the C and N, and the K, H, and O are returning nonsensical values, then a logical possibility is that the E0's for C and N are correct. If you add 12 eV to the E0 you chose in Athena, where in the spectrum does it fall? Is it still before the white line? If so, it seems to me you don't have a problem. If not, then we have to ponder further.

--Scott Calvin Sarah Lawrence College

On Jun 19, 2009, at 8:28 AM, Zajac, Dariusz A. wrote:

...

Hi Scott, look also at H and O, but for me and for this fit important are only W-C and W-C-N bondings. This sample is an reference sample for other cyano-brigded networks. So you suggest to focuse on K ions? how can it help with first 2 peaks? K is at ~5A. I have analysed in larger R space only to see how the spectrum behave. contribution from K, O etc. at k highers than 5A is for me too low to analyse it resonable for such compound. I have attached in the previus post the last version of results. Anyway, enots for C and N do not change if I am enlarging R region (when I am including next paths, also for K). about material I am quite sure ;) and crystal structure is from literature

in the attachment you will find bmp file of the fit: data, fit, bkg and K path. fitting ranges k(3-15) R(1.7-6) dk 2 dr 0.5, phase correction - first C

cheers darek

_______________________________________________ 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

------------------------------

Message: 4 Date: Sat, 20 Jun 2009 12:44:34 +0200 From: Stefan Mangold Subject: Re: [Ifeffit] problem with E0 (enot) parameters To: XAFS Analysis using Ifeffit Message-ID: <6F3358E1-7C2C-4FA2-B3B3-AD9FF7B0C5F3@iss.fzk.de> Content-Type: text/plain; charset="iso-8859-1"

Please do not attach 10 Mb of data on your Mails. Just send an Link to an Web-space with your e-mail. People can then download the stuff if needed.

Best regards

Stefan

Am 19.06.2009 um 16:44 schrieb Zajac, Dariusz A.:

...

Hi Scott, I am afraid that E0 jumps over the edge - see bmp's in the attachment (files with enot_12 means E0=12...). Hovewer 12 eV is still less than k=3 (the starting k value). Can it influence? I did also once more fit with R from 1.7 to 4A. Fits of first 2 peaks are identical - you can see in the attachment too... I hope you and anyone from the mailing list don't mind that I am attaching so many files...

cheers darek

...

-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of Scott Calvin Sent: Friday, June 19, 2009 2:49 PM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] problem with E0 (enot) parameters

Hi Darek,

OK, so if the K, H, and O don't affect the fit much for the C and N, and the K, H, and O are returning nonsensical values, then a logical possibility is that the E0's for C and N are correct. If you add 12 eV to the E0 you chose in Athena, where in the spectrum does it fall? Is it still before the white line? If so, it seems to me you don't have a problem. If not, then we have to ponder further.

--Scott Calvin Sarah Lawrence College

On Jun 19, 2009, at 8:28 AM, Zajac, Dariusz A. wrote:

...

Hi Scott, look also at H and O, but for me and for this fit important are only W-C and W-C-N bondings. This sample is an reference sample for other cyano-brigded networks. So you suggest to focuse on K ions? how can it help with first 2 peaks? K is at ~5A. I have analysed in larger R space only to see how the spectrum behave. contribution from K, O etc. at k highers than 5A is for me too low to analyse it resonable for such compound. I have attached in the previus post the last version of results. Anyway, enots for C and N do not change if I am enlarging R region (when I am including next paths, also for K). about material I am quite sure ;) and crystal structure is from literature

in the attachment you will find bmp file of the fit: data, fit, bkg and K path. fitting ranges k(3-15) R(1.7-6) dk 2 dr 0.5, phase correction - first C

cheers darek

_______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit

< K4W (CN )8_enot_12 .bmp

...

< K4W (CN )8_enot_0.bmp><mime- attachment.txt>

-- Dr. Stefan Mangold Institut f?r Synchrotronstrahlung Forschungszentrum Karlsruhe Tel.: +49-7247-826073