[Ifeffit] Ifeffit Digest, Vol 150, Issue 3
Abhijeet Gaur
abhijeetgaur9 at gmail.com
Tue Aug 4 02:30:11 CDT 2015
Hi Max,
Thanks for the explaning the probable reason of smaller
particle sizes determined by EXAFS. I will also try to refine my fittings.
Hi Anatoly,
Can you please send me the link of that recent paper
again as I am unable to find it in your earlier message.
Abhijeet
On Mon, Aug 3, 2015 at 6:04 PM, <ifeffit-request at millenia.cars.aps.anl.gov>
wrote:
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> Today's Topics:
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> 1. Re: Ifeffit Digest, Vol 150, Issue 2 (Abhijeet Gaur)
> 2. Re: Measuring particle size by coordination number (Maxim Boyanov)
> 3. Re: Measuring particle size by coordination number
> (Anatoly I Frenkel)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 3 Aug 2015 13:49:40 +0200
> From: Abhijeet Gaur <abhijeetgaur9 at gmail.com>
> To: ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> Subject: Re: [Ifeffit] Ifeffit Digest, Vol 150, Issue 2
> Message-ID:
> <
> CAEq27Q1Fde2qTQyrgaAMaTJ1wUpoXydxOcS0v73MPXdAKJs_zA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Scott,
>
> Thanks for your quick reply. So, I have to add more paths to
> the fitting and then try to determine the size of the particle.
>
> Also, I want to add some analysis details to confirm that I am
> on the right path.
>
> The value of amp is obtained from fitting of metal foil, i.e.,
> 0.84 (0.03) and is kept fixed during the fitting of the sample.
>
> S02 is defined by the formula S02 =
> amp*(1-(0.75*(Reff/R))+(0.063*(Reff*Reff*Reff/(R*R*R)))).
>
> With thanks
>
> Abhijeet
>
>
>
>
> >
> >
> > Message: 2
> > Date: Mon, 3 Aug 2015 07:11:53 -0400
> > From: Scott Calvin <scalvin at sarahlawrence.edu>
> > To: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> > Subject: Re: [Ifeffit] Measuring particle size by coordination number
> > Message-ID: <C61F6046-713C-4EC2-8F7A-536ECC43DEA5 at slc.edu>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Hi Abhijeet,
> >
> > The formula looks poorly when it is only applied with one path.
> >
> > The strength of this approach, and of Anatoly Frenkel?s alternative
> > strategy for finding particle sizes, is that it compares coordination
> > numbers for different shells, helping to break the correlations between
> N,
> > S02, and sigma2.
> >
> > Even then, it tends to report sizes that are small compared to those
> > provided by other techniques, but compares sizes between different
> samples
> > quite well.
> >
> > ?Scott Calvin
> > Sarah Lawrence College
> >
> >
> >
>
>
> --
> *Dr. Abhijeet Gaur*
> *Post doctoral fellow in the Institute for Chemical Technology and Polymer
> Chemistry *
> *Karlsruher Institut f?r Technologie (KIT), Karlsruhe Germany.*
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>
> ------------------------------
>
> Message: 2
> Date: Mon, 3 Aug 2015 10:54:05 -0500
> From: "Maxim Boyanov" <mboyanov at nd.edu>
> To: "'XAFS Analysis using Ifeffit'"
> <ifeffit at millenia.cars.aps.anl.gov>
> Subject: Re: [Ifeffit] Measuring particle size by coordination number
> Message-ID: <001a01d0ce04$a13d13f0$e3b73bd0$@nd.edu>
> Content-Type: text/plain; charset="utf-8"
>
> An additional reason for the discrepancy in particle sizes between EXAFS
> and TEM may be that TEM detects only particles above a cut-off size,
> whereas particles of all sizes (including single ion complexes) contribute
> to the EXAFS signal. Assuming that EXAFS is 100% accurate in determining
> particle size ;-), this would result in smaller sizes reported by EXAFS and
> will be noticeable if a significant fraction of the atoms are in particles
> with sizes below the detection limit of TEM.
>
>
>
> -Max
>
>
>
> From: ifeffit-bounces at millenia.cars.aps.anl.gov [mailto:
> ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf Of Scott Calvin
> Sent: Monday, August 3, 2015 6:12 AM
> To: XAFS Analysis using Ifeffit
> Subject: Re: [Ifeffit] Measuring particle size by coordination number
>
>
>
> Hi Abhijeet,
>
>
>
> The formula looks poorly when it is only applied with one path.
>
>
>
> The strength of this approach, and of Anatoly Frenkel?s alternative
> strategy for finding particle sizes, is that it compares coordination
> numbers for different shells, helping to break the correlations between N,
> S02, and sigma2.
>
>
>
> Even then, it tends to report sizes that are small compared to those
> provided by other techniques, but compares sizes between different samples
> quite well.
>
>
>
> ?Scott Calvin
>
> Sarah Lawrence College
>
>
>
> On Aug 3, 2015, at 4:41 AM, Abhijeet Gaur <abhijeetgaur9 at gmail.com
> <mailto:abhijeetgaur9 at gmail.com> > wrote:
>
>
>
> Hi all,
>
>
>
> Sorry, I may be asking a question already asked in the
> mailing list, but I am unable to get it from the earlier discussions.
>
>
>
> I am reading one of the research article ?? Determination
> of crystallite size in a magnetic nanocomposite using extended x-ray
> absorption fine structure?? .J. Appl. Phys,. vol 94, page 778, 2003
>
>
>
> In this paper there is a formula N_nano =
> [1-3/4(r/R)+1/16(r/R)^3]N_bulk, which you said can be used in the Artemis
> for extracting the particle size.
>
>
>
> I am trying to use this formula for determination of size
> of Ni particles in an Ni / Al2O3 catalyst. From TEM the size determined is
> around 4 nm.
>
>
>
> So, I am trying to fit the theoretical model of Ni metal to
> the sample data in the Artemis
>
>
>
> I defined a guessed parameter R and then put the whole
> formula for S02 = amp*(1-(0.75*(Reff/R))+(0.063*(Reff*Reff*Reff/(R*R*R)))).
>
>
>
> The value of R I am getting is 0.81 (0.05) which is quite
> small.
>
>
>
> Is there something I am missing in the formula or I have to
> define the N seprately for sample cooridnation number.
>
>
>
> Currently, I am using only the first path in the fitting.
>
>
>
>
>
>
>
> With thanks
>
>
>
>
>
> Abhijeet Gaur
>
>
>
>
>
> --
>
> Dr. Abhijeet Gaur
>
> Post doctoral fellow in the Institute for Chemical Technology and Polymer
> Chemistry
>
> Karlsruher Institut f?r Technologie (KIT), Karlsruhe Germany.
>
> _______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov <mailto:
> Ifeffit at millenia.cars.aps.anl.gov>
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>
>
>
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> ------------------------------
>
> Message: 3
> Date: Mon, 3 Aug 2015 16:02:28 +0000
> From: Anatoly I Frenkel <afrenke2 at yu.edu>
> To: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> Subject: Re: [Ifeffit] Measuring particle size by coordination number
> Message-ID:
> <
> 545F89325F51764C902D37B42C9F4D53017CC2BF8E at YUWEXCPM11.yuad.uds.yu.edu>
>
> Content-Type: text/plain; charset="windows-1252"
>
> As an illustration of the very good comment that Max just made, here is a
> recent paper that explains this discrepancy in detail, and proposes a
> remedy.
>
> Anatoly
>
> Sent from my mobile phone, please forgive typos
>
> ----- Reply message -----
> From: "Maxim Boyanov" <mboyanov at nd.edu>
> To: "'XAFS Analysis using Ifeffit'" <ifeffit at millenia.cars.aps.anl.gov>
> Subject: [Ifeffit] Measuring particle size by coordination number
> Date: Mon, Aug 3, 2015 11:59 AM
>
> An additional reason for the discrepancy in particle sizes between EXAFS
> and TEM may be that TEM detects only particles above a cut-off size,
> whereas particles of all sizes (including single ion complexes) contribute
> to the EXAFS signal. Assuming that EXAFS is 100% accurate in determining
> particle size ;-), this would result in smaller sizes reported by EXAFS and
> will be noticeable if a significant fraction of the atoms are in particles
> with sizes below the detection limit of TEM.
>
> -Max
>
> From: ifeffit-bounces at millenia.cars.aps.anl.gov [mailto:
> ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf Of Scott Calvin
> Sent: Monday, August 3, 2015 6:12 AM
> To: XAFS Analysis using Ifeffit
> Subject: Re: [Ifeffit] Measuring particle size by coordination number
>
> Hi Abhijeet,
>
> The formula looks poorly when it is only applied with one path.
>
> The strength of this approach, and of Anatoly Frenkel?s alternative
> strategy for finding particle sizes, is that it compares coordination
> numbers for different shells, helping to break the correlations between N,
> S02, and sigma2.
>
> Even then, it tends to report sizes that are small compared to those
> provided by other techniques, but compares sizes between different samples
> quite well.
>
> ?Scott Calvin
> Sarah Lawrence College
>
> On Aug 3, 2015, at 4:41 AM, Abhijeet Gaur <abhijeetgaur9 at gmail.com<mailto:
> abhijeetgaur9 at gmail.com>> wrote:
>
> Hi all,
>
> Sorry, I may be asking a question already asked in the
> mailing list, but I am unable to get it from the earlier discussions.
>
> I am reading one of the research article ?? Determination
> of crystallite size in a magnetic nanocomposite using extended x-ray
> absorption fine structure?? .J. Appl. Phys,. vol 94, page 778, 2003
>
> In this paper there is a formula N_nano =
> [1-3/4(r/R)+1/16(r/R)^3]N_bulk, which you said can be used in the Artemis
> for extracting the particle size.
>
> I am trying to use this formula for determination of size
> of Ni particles in an Ni / Al2O3 catalyst. From TEM the size determined is
> around 4 nm.
>
> So, I am trying to fit the theoretical model of Ni metal to
> the sample data in the Artemis
>
> I defined a guessed parameter R and then put the whole
> formula for S02 = amp*(1-(0.75*(Reff/R))+(0.063*(Reff*Reff*Reff/(R*R*R)))).
>
> The value of R I am getting is 0.81 (0.05) which is quite
> small.
>
> Is there something I am missing in the formula or I have to
> define the N seprately for sample cooridnation number.
>
> Currently, I am using only the first path in the fitting.
>
>
>
> With thanks
>
>
> Abhijeet Gaur
>
>
> --
> Dr. Abhijeet Gaur
> Post doctoral fellow in the Institute for Chemical Technology and Polymer
> Chemistry
> Karlsruher Institut f?r Technologie (KIT), Karlsruhe Germany.
> _______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov<mailto:Ifeffit at millenia.cars.aps.anl.gov
> >
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>
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>
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> Ifeffit at millenia.cars.aps.anl.gov
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>
>
> End of Ifeffit Digest, Vol 150, Issue 3
> ***************************************
>
--
*Dr. Abhijeet Gaur*
*Post doctoral fellow in the Institute for Chemical Technology and Polymer
Chemistry *
*Karlsruher Institut für Technologie (KIT), Karlsruhe Germany.*
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