Hello Mike, Thank you very much for your help. I have a question about combining different atoms in a shell. For example, in the Fe5C2 model, ATOMS * this list contains 221 atoms * x y z ipot tag distance 0.00000 0.00000 0.00000 0 Fe1 0.00000 -0.19385 1.76888 -0.78107 4 C1.1 1.94335 -0.19385 -0.94552 1.72493 4 C1.2 1.97661
If I am going to combine C1.1 and C1.2, shall I set them the cartisian coordinate as in FEFF file? ATOMS * this list contains 221 atoms * x y z ipot tag distance 0.00000 0.00000 0.00000 0 Fe1 0.00000 0.00000 0.00000 1.94335 4 C1.1 1.94335 Thanks a lot for your help again! Best, Yunyun On Thu, Oct 26, 2017 at 4:40 PM, Mike Massey <mmas...@gmail.com> wrote: > I definitely recommend combining multiple atoms of similar distances into > the same path. That's what you end up with anyway if you use multiple > paths, with a lot more potential problems in the software. > > Sometimes it is beneficial to split a shell of of atoms into two, to > capture some physical behavior (for example, 2 atoms at 3 Angstroms and 4 > atoms at 3.3 Angstroms, instead of one very disordered shell of 6 atoms at > 3.2 Angstroms). > > Depending on your data quality, I recommend building a fitting model with > maybe 2-8 total "shells" of atoms at different distances. > > > > Mike > > > > On Oct 26, 2017, at 12:52 PM, Yunyun Zhou <yyzhouz...@gmail.com> wrote: > > > > Hello All, > > > > I am having trouble fitting my sample with both Fe5C2 and Fe3O4 as > standards. Hopefully somebody could help me out and I really appreciate it. > > > > My iron sample was mainly iron carbide in the core and iron oxide on the > shell. Fe5C2 has a monoclinic structure and generated complicated FEFF > paths. Many of the paths have similar distances. I have found some paper > reported their results as follows, which apparently combined several paths > together and assume they have similar path length. My first question is > does someone know how they did it? It seems that combing similar paths > makes fitting much easier, but I am not sure whether this is a correct way > to do the fitting. > > > > My second question is regarding fitting with the two combined models of > Fe5C2 and Fe3O4. I haven't fit with two models before. Is it just like what > I did in the attached Artemis file? Shall there be any restrictions between > the two models and do I have to fix some of the parameters? > > > > Thank you very much in advance for your help! > > > > Best, > > > > Yunyun Zhou > > > > Fe5C2 FEff paths: > > <image.png> > > > > Literature reported results: > > <image.png> > > <artemis_CWV 130 spent_example.fpj> > > _______________________________________________ > > Ifeffit mailing list > > Ifeffit@millenia.cars.aps.anl.gov > > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit > > _______________________________________________ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit >
_______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit