Re: [Ifeffit] huge S02 value ??
Hello Anatoly, In addition to Ni aqueous solutions, I and my former group members also collected EXAFS of solutions of many Ni-organic complexes which are octahedral (O)in first shell at differet time and on differet beamlines. All the fitting resulted in high S02 values although bond distances are correct and fitting goodness is good as well. My collegue and I also found that a S02 of 0.85 was obtained from the fitting of Ni aqueous solution if we used feff files created from the artificial single Ni-O path instead of from crystal structures using Feff 6. Using files created from Feff 7 with single Ni-O path resulted in a high value close to 1. I am thinking if this high S02 value comes from the Feff code. The versions of Feff that I use is Feff 7.00 and Feff 6. I am wondering if you can send me your EXAFS data of Ni aqueous solution and the Feff you used to creat these files. Thanks for your time and efforts. Best wishes, Mengqiang --- Mengqiang Zhu Ph.D Candidate Environmental Soil Chemistry Department of Plant and Soil Sciences University of Delaware 152 Townsend Hall Newark, DE 19716 http://ag.udel.edu/soilchem/zhu.html Original message >Date: Sun, 5 Apr 2009 21:54:41 -0400 >From: ifeffit-boun...@millenia.cars.aps.anl.gov (on behalf of "Frenkel, >Anatoly" ) >Subject: Re: [Ifeffit] huge S02 value ?? >To: "XAFS Analysis using Ifeffit" > >Hi, >Very strange. Your data are indeed more intense in k-space than mine, after >they are perfectly aligned. Since you have some systematic noise in the end of >the k-range, I wonder if you should be better off remeasuring this system, >instead of trying to brain storm why it gives high S02. > >Of course, it could mean that my data are wrong and your are right. But this >is not easy to troubleshoot. If you are in doubt, better to look at other >comparisons, between reference materials that you collected during the same >run and those that you had measured earlier. > >Anatoly > > > > > >From: ifeffit-boun...@millenia.cars.aps.anl.gov on behalf of m...@udel.edu >Sent: Sun 4/5/2009 1:47 PM >To: XAFS Analysis using Ifeffit >Subject: Re: [Ifeffit] huge S02 value ?? > > > >Hello Anatoly, > The E0 I used for EXAFS extraction is 8344 ev, which is located in the half > of the edge jump. I tried a higher E0 as you suggested, such as 8347 ev, but > I still got a huge S02 value. In the attchment is the mu(E) and average data > of Ni solution. I very appreciate your help. > >Best wishes, > >Mengqiang Zhu > > > > > > > >--- >Mengqiang Zhu >Ph.D Candidate >Environmental Soil Chemistry >Department of Plant and Soil Sciences >University of Delaware >152 Townsend Hall >Newark, DE 19716 >http://ag.udel.edu/soilchem/zhu.html > > > Original message >>Date: Sun, 5 Apr 2009 12:44:13 -0400 >>From: ifeffit-boun...@millenia.cars.aps.anl.gov (on behalf of "Frenkel, >>Anatoly" ) >>Subject: Re: [Ifeffit] huge S02 value ?? >>To: "XAFS Analysis using Ifeffit" , >> >> >>Hi Mengqiang, >> >>I have done fits of aqueous solution of NiSO4 before and obtained S02 of 0.8 >>for the octahedrally coordinated Ni-O shell. You did not send the mu(E) data, >>just chi(k), so I was not able to compare my and your raw data fully, just in >>k-space. Here is what I found: my data is in perfect agreement in k-space >>with yours, only if I move E0 down to the pre-edge region, and I suspect, >>therefore, it is where you chose your E0. >> >>As a result, the entire, very intense, main absorption peak became a part of >>your EXAFS, increasing the intensity of the k-space signal (since it became >>the first half-cycle of the EXAFS oscillation), and thus you got such a large >>S02. If you move your E0 to half-the edge jump, your result will be the same >>as mine, 0.8 >> >>Let me know if it helped, >>Anatoly >> >> >> >>From: ifeffit-boun...@millenia.cars.aps.anl.gov on behalf of m...@udel.edu >>Sent: Sat 4/4/2009 10:04 PM >>To: ifeffit@millenia.cars.aps.anl.gov >>Subject: [Ifeffit] huge S02 value ?? >> >> >> >>Hello everyone, >> I have been fitting EXAFS of NiSO4 aqueous solution. The feff files were >> created from Ni(OH)2 using Feff7.00. During the fitting, coordination number >> was fixed as 6. The S02 derived from fitting is 1.22. I tried other >> materials for creating feff files, such as NiCO3 and NiPO4, and I got the >> similar S02 values. I also tried Feff6, it did not result in a reasonable >> S02 value, either. >> Anyone can tell me why it led to such high S02 value? The data file and >> feff input file (Feff 7) are attached. >> Thanks in advance. >> >>Best wishes, >> >>Mengqiang Zhu >> >> >> >> >> >> >> >> >>--- >>Mengqiang Zhu >>Ph.D Candidate >>Environmental Soil Chemistry >>Department of Plant and Soil Sciences >>University of Delaware >>152 Townsend Hall >>Newark, DE 19716 >>http://ag.udel.edu/so
Re: [Ifeffit] huge S02 value ??
Hi, Very strange. Your data are indeed more intense in k-space than mine, after they are perfectly aligned. Since you have some systematic noise in the end of the k-range, I wonder if you should be better off remeasuring this system, instead of trying to brain storm why it gives high S02. Of course, it could mean that my data are wrong and your are right. But this is not easy to troubleshoot. If you are in doubt, better to look at other comparisons, between reference materials that you collected during the same run and those that you had measured earlier. Anatoly From: ifeffit-boun...@millenia.cars.aps.anl.gov on behalf of m...@udel.edu Sent: Sun 4/5/2009 1:47 PM To: XAFS Analysis using Ifeffit Subject: Re: [Ifeffit] huge S02 value ?? Hello Anatoly, The E0 I used for EXAFS extraction is 8344 ev, which is located in the half of the edge jump. I tried a higher E0 as you suggested, such as 8347 ev, but I still got a huge S02 value. In the attchment is the mu(E) and average data of Ni solution. I very appreciate your help. Best wishes, Mengqiang Zhu --- Mengqiang Zhu Ph.D Candidate Environmental Soil Chemistry Department of Plant and Soil Sciences University of Delaware 152 Townsend Hall Newark, DE 19716 http://ag.udel.edu/soilchem/zhu.html Original message >Date: Sun, 5 Apr 2009 12:44:13 -0400 >From: ifeffit-boun...@millenia.cars.aps.anl.gov (on behalf of "Frenkel, >Anatoly" ) >Subject: Re: [Ifeffit] huge S02 value ?? >To: "XAFS Analysis using Ifeffit" , > > >Hi Mengqiang, > >I have done fits of aqueous solution of NiSO4 before and obtained S02 of 0.8 >for the octahedrally coordinated Ni-O shell. You did not send the mu(E) data, >just chi(k), so I was not able to compare my and your raw data fully, just in >k-space. Here is what I found: my data is in perfect agreement in k-space with >yours, only if I move E0 down to the pre-edge region, and I suspect, >therefore, it is where you chose your E0. > >As a result, the entire, very intense, main absorption peak became a part of >your EXAFS, increasing the intensity of the k-space signal (since it became >the first half-cycle of the EXAFS oscillation), and thus you got such a large >S02. If you move your E0 to half-the edge jump, your result will be the same >as mine, 0.8 > >Let me know if it helped, >Anatoly > > > >From: ifeffit-boun...@millenia.cars.aps.anl.gov on behalf of m...@udel.edu >Sent: Sat 4/4/2009 10:04 PM >To: ifeffit@millenia.cars.aps.anl.gov >Subject: [Ifeffit] huge S02 value ?? > > > >Hello everyone, > I have been fitting EXAFS of NiSO4 aqueous solution. The feff files were > created from Ni(OH)2 using Feff7.00. During the fitting, coordination number > was fixed as 6. The S02 derived from fitting is 1.22. I tried other materials > for creating feff files, such as NiCO3 and NiPO4, and I got the similar S02 > values. I also tried Feff6, it did not result in a reasonable S02 value, > either. > Anyone can tell me why it led to such high S02 value? The data file and > feff input file (Feff 7) are attached. > Thanks in advance. > >Best wishes, > >Mengqiang Zhu > > > > > > > > >--- >Mengqiang Zhu >Ph.D Candidate >Environmental Soil Chemistry >Department of Plant and Soil Sciences >University of Delaware >152 Townsend Hall >Newark, DE 19716 >http://ag.udel.edu/soilchem/zhu.html > > > >___ >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
Re: [Ifeffit] huge S02 value ??
Hello Anatoly, The E0 I used for EXAFS extraction is 8344 ev, which is located in the half of the edge jump. I tried a higher E0 as you suggested, such as 8347 ev, but I still got a huge S02 value. In the attchment is the mu(E) and average data of Ni solution. I very appreciate your help. Best wishes, Mengqiang Zhu --- Mengqiang Zhu Ph.D Candidate Environmental Soil Chemistry Department of Plant and Soil Sciences University of Delaware 152 Townsend Hall Newark, DE 19716 http://ag.udel.edu/soilchem/zhu.html Original message >Date: Sun, 5 Apr 2009 12:44:13 -0400 >From: ifeffit-boun...@millenia.cars.aps.anl.gov (on behalf of "Frenkel, >Anatoly" ) >Subject: Re: [Ifeffit] huge S02 value ?? >To: "XAFS Analysis using Ifeffit" , > > >Hi Mengqiang, > >I have done fits of aqueous solution of NiSO4 before and obtained S02 of 0.8 >for the octahedrally coordinated Ni-O shell. You did not send the mu(E) data, >just chi(k), so I was not able to compare my and your raw data fully, just in >k-space. Here is what I found: my data is in perfect agreement in k-space with >yours, only if I move E0 down to the pre-edge region, and I suspect, >therefore, it is where you chose your E0. > >As a result, the entire, very intense, main absorption peak became a part of >your EXAFS, increasing the intensity of the k-space signal (since it became >the first half-cycle of the EXAFS oscillation), and thus you got such a large >S02. If you move your E0 to half-the edge jump, your result will be the same >as mine, 0.8 > >Let me know if it helped, >Anatoly > > > >From: ifeffit-boun...@millenia.cars.aps.anl.gov on behalf of m...@udel.edu >Sent: Sat 4/4/2009 10:04 PM >To: ifeffit@millenia.cars.aps.anl.gov >Subject: [Ifeffit] huge S02 value ?? > > > >Hello everyone, > I have been fitting EXAFS of NiSO4 aqueous solution. The feff files were > created from Ni(OH)2 using Feff7.00. During the fitting, coordination number > was fixed as 6. The S02 derived from fitting is 1.22. I tried other materials > for creating feff files, such as NiCO3 and NiPO4, and I got the similar S02 > values. I also tried Feff6, it did not result in a reasonable S02 value, > either. > Anyone can tell me why it led to such high S02 value? The data file and > feff input file (Feff 7) are attached. > Thanks in advance. > >Best wishes, > >Mengqiang Zhu > > > > > > > > >--- >Mengqiang Zhu >Ph.D Candidate >Environmental Soil Chemistry >Department of Plant and Soil Sciences >University of Delaware >152 Townsend Hall >Newark, DE 19716 >http://ag.udel.edu/soilchem/zhu.html > > > >___ >Ifeffit mailing list >Ifeffit@millenia.cars.aps.anl.gov >http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit # Averaged Data E:/XAFS data reduction/Ni_organic/Niaqueous_fl.avg created by SamView 8202.2409 0.0503432191908 8212.23413 0.0506953708827 8222.2525 0.0511789694428 8232.25978 0.0514279566705 8242.2558 0.0518624223769 8252.24038 0.0525789260864 8262.24992 0.0531375817955 8272.24784 0.0537167079747 8282.23396 0.0542418546975 8292.24495 0.0547551847994 8302.24396 0.0557973235846 8302.76118 0.0557101033628 8303.24153 0.0556985065341 8303.75888 0.0558634921908 8304.23935 0.0559157207608 8304.75683 0.0559655353427 8305.23741 0.055898886174 8305.75502 0.055989921093 8306.23572 0.0560606531799 8306.75347 0.0560192279518 8307.23428 0.0562393777072 8307.75215 0.0562160164118 8308.23309 0.0561975836754 8308.75109 0.0563822872937 8309.23215 0.0565039329231 8309.75027 0.0565173178911 8310.23145 0.0564906336367 8310.7497 0.056623019278 8311.2310.0567095503211 8311.74938 0.0567882247269 8312.2308 0.0567082725465 8312.74931 0.056889321655 8313.23084 0.056946605444 8313.74948 0.0570479556918 8314.23113 0.0570488572121 8314.7499 0.0571002848446 8315.23167 0.0570758283138 8315.75057 0.0572652854025 8316.23246 0.0573980659246 8316.75149 0.0573919713497 8317.2335 0.0573230311275 8317.75265 0.057468816638 8318.23479 0.0576100423932 8318.75407 0.057746309787 8319.23632 0.0577853955328 8319.75573 0.0579555816948 8320.2381 0.058120302856 8320.75764 0.0578925535083 8321.24013 0.0581668056548 8321.7598 0.05829712376 8322.24241 0.0583414137363 8322.76221 0.0584905035794 8323.24494 0.0585640184581 8323.76487 0.058735050261 8324.24771 0.0589188709855 8324.73062 0.0589252784848 8325.25074 0.0591709502041 8325.73377 0.0592750348151 8326.25401 0.0594279393554 8326.73716 0.0597358644009 8327.25754 0.0597774200141 8327.7408 0.0600643604994 8328.26131 0.0602235011756 8328.7447 0.0604247003794 8329.26533 0.0606681294
Re: [Ifeffit] huge S02 value ??
Hi Mengqiang, I have done fits of aqueous solution of NiSO4 before and obtained S02 of 0.8 for the octahedrally coordinated Ni-O shell. You did not send the mu(E) data, just chi(k), so I was not able to compare my and your raw data fully, just in k-space. Here is what I found: my data is in perfect agreement in k-space with yours, only if I move E0 down to the pre-edge region, and I suspect, therefore, it is where you chose your E0. As a result, the entire, very intense, main absorption peak became a part of your EXAFS, increasing the intensity of the k-space signal (since it became the first half-cycle of the EXAFS oscillation), and thus you got such a large S02. If you move your E0 to half-the edge jump, your result will be the same as mine, 0.8 Let me know if it helped, Anatoly From: ifeffit-boun...@millenia.cars.aps.anl.gov on behalf of m...@udel.edu Sent: Sat 4/4/2009 10:04 PM To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] huge S02 value ?? Hello everyone, I have been fitting EXAFS of NiSO4 aqueous solution. The feff files were created from Ni(OH)2 using Feff7.00. During the fitting, coordination number was fixed as 6. The S02 derived from fitting is 1.22. I tried other materials for creating feff files, such as NiCO3 and NiPO4, and I got the similar S02 values. I also tried Feff6, it did not result in a reasonable S02 value, either. Anyone can tell me why it led to such high S02 value? The data file and feff input file (Feff 7) are attached. Thanks in advance. Best wishes, Mengqiang Zhu --- Mengqiang Zhu Ph.D Candidate Environmental Soil Chemistry Department of Plant and Soil Sciences University of Delaware 152 Townsend Hall Newark, DE 19716 http://ag.udel.edu/soilchem/zhu.html ___ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
