Re: [Ifeffit] Fe K-edge maghemite (gamma-Fe2O3)
Dear XAFS community, I wonder if anyone has a CuSiO3 spectrum measured at Cu K-edge? Thank you, again! Em sex., 9 de fev. de 2024 às 05:58, Morgane Desmau < morgane.des...@gmail.com> escreveu: > Hi, > > I have some but for nanoparticles maghemite (room temperature and 20K, > continuous scanning mode). > > Best, > Morgane Desmau > > Le jeu. 8 févr. 2024, à 13 h 11, Christian Wittee Lopes < > chriswit...@gmail.com> a écrit : > >> Dear XAFS community, >> >> Does anyone have a Fe K-edge XAS spectrum of maghemite (gamma-Fe2O3) >> sample or standard? >> >> Thank you in advance. >> >> Best, >> >> Christian Wittee Lopes >> >> -- >> >> Christian Wittee Lopes >> >> Professor Adjunto >> >> *Departamento de Química - Setor de Ciências Exatas* >> >> Universidade Federal do Paraná (UFPR) >> >> *Curitiba - Paraná* >> >> *LinkedIn >> <https://urldefense.us/v3/__https://www.linkedin.com/in/christian-wittee-lopes-561855219/__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqAOhHj9aw$ >> > >> | ORCID >> <https://urldefense.us/v3/__https://orcid.org/my-orcid?orcid=-0001-8420-1958__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqBwDSzRLg$ >> > | Lattes >> <https://urldefense.us/v3/__http://lattes.cnpq.br/4953371870936050__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqAy7MN43w$ >> >* >> ___ >> Ifeffit mailing list >> Ifeffit@millenia.cars.aps.anl.gov >> https://urldefense.us/v3/__http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqBqZw1wkg$ >> >> Unsubscribe: >> https://urldefense.us/v3/__http://millenia.cars.aps.anl.gov/mailman/options/ifeffit__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqAqjmdJBg$ >> >> > ___ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > https://urldefense.us/v3/__http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqBqZw1wkg$ > > Unsubscribe: > https://urldefense.us/v3/__http://millenia.cars.aps.anl.gov/mailman/options/ifeffit__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqAqjmdJBg$ > > -- Christian Wittee Lopes Professor Adjunto *Departamento de Química - Setor de Ciências Exatas* Universidade Federal do Paraná (UFPR) *Curitiba - Paraná* *LinkedIn <https://urldefense.us/v3/__https://www.linkedin.com/in/christian-wittee-lopes-561855219/__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqAOhHj9aw$ > | ORCID <https://urldefense.us/v3/__https://orcid.org/my-orcid?orcid=-0001-8420-1958__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqBwDSzRLg$ > | Lattes <https://urldefense.us/v3/__http://lattes.cnpq.br/4953371870936050__;!!G_uCfscf7eWS!eFcwWUu4VfNRwi1wTzYci8AJYPyrJYLXh7duGqtivxZv1AE5mPoYiXb1ENtYktsPKLMGbv5u888KMTqMfkK2xOaYxqAy7MN43w$ >* ___ 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] Fe K-edge maghemite (gamma-Fe2O3)
Dear XAFS community, Does anyone have a Fe K-edge XAS spectrum of maghemite (gamma-Fe2O3) sample or standard? Thank you in advance. Best, Christian Wittee Lopes -- Christian Wittee Lopes Professor Adjunto *Departamento de Química - Setor de Ciências Exatas* Universidade Federal do Paraná (UFPR) *Curitiba - Paraná* *LinkedIn <https://www.linkedin.com/in/christian-wittee-lopes-561855219/> | ORCID <https://orcid.org/my-orcid?orcid=-0001-8420-1958> | Lattes <http://lattes.cnpq.br/4953371870936050>* ___ 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] Co(OH)2 spectrum
Hi folks, Does anyone have a spectrum of bulk cobalt hydroxide Co(OH)2 by chance? Thank you in advance. Christian Wittee Lopes -- Christian Wittee Lopes Visiting Researcher - ANP/FINEP - PRH 50.1 Institute of Chemistry, Universidade Federal do Rio Grande do Sul (UFRGS) chriswit...@gmail.com LinkedIn <https://www.linkedin.com/in/christian-wittee-lopes-561855219/> | ORCID <https://orcid.org/my-orcid?orcid=-0001-8420-1958> | Lattes <http://lattes.cnpq.br/4953371870936050> ___ 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
Re: [Ifeffit] Co2P spectrum
Dear Hiraoka, Thank you very much! Christian Em seg., 12 de set. de 2022 às 21:03, Yuji Hiraoka escreveu: > Dear Lopes, > > You can download Co2P spectrum from following URL. > By using Si(311) plane as a monochromator: > https://mdr.nims.go.jp/concern/datasets/8336h411j?locale=en > By using Si(111) plane as a monochromator: > https://mdr.nims.go.jp/concern/datasets/p2676x842?locale=en > > These data is originally uploaded at https://benten.spring8.or.jp/ , and > provided to above databases. If you have a interest, see this also. > > Sincerely, > > Yuji Hiraoka > > >Dear XAFS community, > > > >Does anyone have a spectrum of Co2P sample or standard? > > > >Thank you in advance. > > > >Best, > > > >Christian Wittee Lopes > > > >-- > > > >Christian Wittee Lopes > > > >Visiting Researcher - ANP/FINEP - PRH 50.1 > > > >Institute of Chemistry, Universidade Federal do Rio Grande do Sul (UFRGS) > > > >chriswit...@gmail.com > > > >LinkedIn <https://www.linkedin.com/in/christian-wittee-lopes-561855219/> > | > >ORCID <https://orcid.org/my-orcid?orcid=-0001-8420-1958> | Lattes > ><http://lattes.cnpq.br/4953371870936050> > > > > > >html-part included links--- > >mailto:chriswit...@gmail.com > > > >---text/plain--- > >___ > >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 > -- Christian Wittee Lopes Visiting Researcher - ANP/FINEP - PRH 50.1 Institute of Chemistry, Universidade Federal do Rio Grande do Sul (UFRGS) chriswit...@gmail.com LinkedIn <https://www.linkedin.com/in/christian-wittee-lopes-561855219/> | ORCID <https://orcid.org/my-orcid?orcid=-0001-8420-1958> | Lattes <http://lattes.cnpq.br/4953371870936050> ___ 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] Co2P spectrum
Dear XAFS community, Does anyone have a spectrum of Co2P sample or standard? Thank you in advance. Best, Christian Wittee Lopes -- Christian Wittee Lopes Visiting Researcher - ANP/FINEP - PRH 50.1 Institute of Chemistry, Universidade Federal do Rio Grande do Sul (UFRGS) chriswit...@gmail.com LinkedIn <https://www.linkedin.com/in/christian-wittee-lopes-561855219/> | ORCID <https://orcid.org/my-orcid?orcid=-0001-8420-1958> | Lattes <http://lattes.cnpq.br/4953371870936050> ___ 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] Nanocrystalline NiO
Dear all, Firstly I would like to wish you a much better year than in 2020. Does anyone have some spectra of nanocrystalline NiO (not bulk standards)? I have a spectrum of a mixed compound and would like to get more insights into what I really have in this sample. Thank you in advance!!! Kind regards, -- *Christian Wittee Lopes* *Visiting Researcher* ANP/FINEP - PRH50 Institute of Chemistry, Universidade Federal do Rio Grande do Sul (UFRGS) Phone: +55 54 992430264 ___ 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] Ga standards
Dear colleagues, Does anyone have the XANES spectra of the different Ga2O3 polymorphs (alfa, beta, gamma) and α-GaOOH? I'm treating some data and I need to rule out the presence of such phases in my samples. Thanks in advance!!! -- *Christian Wittee Lopes* *Postdoctoral Researcher* Institute of Physics, Universidade Federal do Rio Grande do Sul (UFRGS) Phone: +55 54 992430264 ___ 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
Re: [Ifeffit] XAFS detection limit
Hi Chris and Matt,
Thank you for the complete information, this will help a lot. It is always
good to have such experienced people contributing to someone else's growth.
Kind regards,
Christian
Em dom., 9 de fev. de 2020 às 11:50, Matt Newville <
newvi...@cars.uchicago.edu> escreveu:
> Hi Christian,
>
> On Thu, Feb 6, 2020, 8:40 PM Christian Wittee Lopes
> wrote:
>
>> Dear all,
>>
>> Recently I was questioned about the EXAFS detection limit when describing
>> different metal species in a bimetallic sample.
>>
>> By checking Pd and Cu K-edges, for example, I found Pd metal
>> nanoparticles and CuO clusters, respectively. But additional techniques
>> tell me I can have copper atoms in intimate contact with the Pd
>> nanoparticles. What would be the minimum amount of these "single atoms"
>> needed to be detected by EXAFS? is there a detection limit or it depends on
>> several parameters?
>>
>
> As Chris Chantler says, there are a lot of things that can influence this,
> so there really isn't one simple answer. Also, as Chris says, advances in
> analytic methods have been (mostly) been improving the situation.
>
> At my beamline, we often get asked questions about detection limits.
> We're typically working in a different context than
> nanoparticles/catalysts, but I think the basic ideas are about the same.
>
> A good starting rule-of-thumb for absolute detection limits is 1 ppm by
> atomic weight. You might be able to do better sometimes, but there are
> situations where XANES at 10 ppm is very hard. For sure, a matrix of
> light elements is much better than a matrix of heavy elements.
>
> For very dilute samples, one will be using fluorescence XAFS measurements
> with a solid-state detector or know very well why you are doing something
> different. These solid-state detectors and electronics are fundamentally
> limited to have energy resolutions of ~120 eV (often 250 eV) and maximum
> total count rates of 5 MHz (often 0.5 MHz). Many beamlines use "a
> handful" (2 to 16) parallel detectors, and some have up to 100 (but often
> with each having a lower individual maximum count rate, and perhaps
> less-than-ideal energy resolution).
> With a count rate of a few MHz total and a sample with 1ppm of "element of
> interest", the elastic and Compton scattering and/or fluorescence from
> other elements will dominate that total count rate and the energy
> resolution will give non-zero background in the fluorescence spectrum.
> That means that even seeing a peak from 1 ppm of an element in an X-ray
> fluorescence spectrum with a solid-state detector is challenging. Not
> impossible, but definitely not routine.
>
> For sure, adding more detectors or counting for a long time can help. But
> those are linear in time and the number of detectors (and no beamline has
> 1000 parallel detectors). Low Z matrices like water, biological material,
> carbon-rich materials are easier. Samples with nearby or overlapping
> fluorescence lines are much harder. That is 10 ppm Zn in water: yes, 1
> ppm Zn in water: maybe, 10 ppm Zn in CaCO3: maybe, 100 ppm Zn in Cu metal:
> no. For sure, XANES at 1ppm is sometimes possible. Getting interpretable
> XAFS would take a lot longer, perhaps days of counting.
>
> Using filters and/or Bent Laue Analyzers in front of a solid-state (or
> integrating) detector can sometimes help to eliminate the unwanted scatter
> signals before they get to the solid-state detector. Using crystal
> analyzers ("wavelength" vs "energy" dispersive fluorescence) can help -
> they have lower backgrounds and are not limited by the total scatter - but
> the solid angle for these tend to be small. Using crystal analyzer arrays
> are probably really needed to get the best detection limits. A few
> beamlines do regularly do HERFD analysis with arrays of crystal analyzers,
> and many of the rest of us are trying to catch up. Still, I believe that
> "1 ppm" is around the state of the art, if not "heroic".
>
> All of that is for the detection limit of an atomic species. If you are
> asking about detecting Cu in/on/with Pd nanoparticles with CuO also
> present, the answer is far worse. Cu XAS measurements will be an average
> of all Cu atoms in the illuminated volume -- you cannot avoid the CuO.
> Seeing that 1% of the Cu atoms are bound to Pd and not to oxygen would be
> very challenging.
>
> Hope that helps,
> --Matt
>
> ___
> 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/
[Ifeffit] XAFS detection limit
Dear all, Recently I was questioned about the EXAFS detection limit when describing different metal species in a bimetallic sample. By checking Pd and Cu K-edges, for example, I found Pd metal nanoparticles and CuO clusters, respectively. But additional techniques tell me I can have copper atoms in intimate contact with the Pd nanoparticles. What would be the minimum amount of these "single atoms" needed to be detected by EXAFS? is there a detection limit or it depends on several parameters? Thanks!!! -- *Christian Wittee Lopes* *Postdoctoral Researcher* Institute of Physics, Universidade Federal do Rio Grande do Sul (UFRGS) Phone: +55 54 992430264 ___ 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
