[Ifeffit] Ifeffit Digest, Vol 167, Issue 3
Raj kumar
rajrk37 at gmail.com
Wed Jan 4 07:42:45 CST 2017
Hi Bruce,
I agree with your comments. Side phase with less than 5% in total
composition cannot be easily detected using regular XRD but comprehensively
using EXAFS. Here, i have also recorded bulk sample, similar to
nanoparticles composition, which is completely free from contamination.
>From this data, i have ruled out the presence of heavy metals.
Regards,
Raj
On 4 January 2017 at 12:38, <ifeffit-request at millenia.cars.aps.anl.gov>
wrote:
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> 1. Re: Ifeffit Digest, Vol 167, Issue 2 (Raj kumar)
> 2. Re: Ifeffit Digest, Vol 167, Issue 2 (Bruce Ravel)
> 3. Re: Ifeffit Digest, Vol 167, Issue 2 (Raj kumar)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 3 Jan 2017 21:32:51 +0100
> From: Raj kumar <rajrk37 at gmail.com>
> To: ifeffit at millenia.cars.aps.anl.gov
> Subject: Re: [Ifeffit] Ifeffit Digest, Vol 167, Issue 2
> Message-ID:
> <CACc-a9+uy+4i65LrZf8kiJRk6bdTD2cVSdeeGLp2r0x4fDBrSQ at mail.
> gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Scott,
>
> Thank you very much for your prompt response. EXAFS measurement was done
> after the XRD characterization. From XRD, it is confirmed that there is no
> side phase formation and contamination. Hence, i guess the heavier element
> role could be avoided here.
>
> Split distances could be the reason??. The following is the method, i have
> opted for modelling the obtained curve. Since YbVO4 is zircon structure, i
> have constrained distance in paths 3, 8 and 9 with the pre-structural info
> and let other distances vary with regular mathematical expression
> alpha*Reff. am i doing wrong here? Before this, I have tried alpha*Reff for
> all paths but fit failed miserably for multi-shells.
>
> Regards,
> Raj
>
> On 3 January 2017 at 19:00, <ifeffit-request at millenia.cars.aps.anl.gov>
> wrote:
>
> > Send Ifeffit mailing list submissions to
> > ifeffit at millenia.cars.aps.anl.gov
> >
> > To subscribe or unsubscribe via the World Wide Web, visit
> > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> > or, via email, send a message with subject or body 'help' to
> > ifeffit-request at millenia.cars.aps.anl.gov
> >
> > You can reach the person managing the list at
> > ifeffit-owner at millenia.cars.aps.anl.gov
> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of Ifeffit digest..."
> >
> >
> > Today's Topics:
> >
> > 1. Re: Problem with large so2 (Scott Calvin)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Tue, 3 Jan 2017 09:59:18 -0600
> > From: Scott Calvin <dr.scott.calvin at gmail.com>
> > To: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> > Subject: Re: [Ifeffit] Problem with large so2
> > Message-ID: <3EF5E209-7681-49C6-9713-4BBF34C619A5 at gmail.edu>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Hi Raj,
> >
> > I haven?t looked at your files, but the kinds of results you are
> > describing often indicate the model you are using beyond the first shell
> is
> > incorrect. It may be that it has the wrong elements (e.g., heavier
> elements
> > are present than what you modelled) or that the model includes split
> > distances when in reality the compound is more symmetric.
> >
> > In short, no, the high second S02 does not make sense (although it would
> > be good to know the uncertainties).
> >
> > Best,
> > Scott Calvin
> > Lehman College of the City University of New York
> >
> > > On Jan 3, 2017, at 9:38 AM, Raj kumar <rajrk37 at gmail.com> wrote:
> > >
> > > Dear All,
> > >
> > >
> > >
> > > I have been trying to fit EXAFS signal of YbVO4 both in bulk and
> > nanoparticles form. Here, I would like to estimate so2 from bulk
> > (reference) and subsequently use the number, as normalization parameter,
> to
> > calculate the co-ordination number in all nanoparticles. Nanoparticles
> were
> > synthesized by solution route. From our earlier understanding on the
> > synthesis, in some cases, Yb may or may not completely involve in
> reaction.
> > Therefore, I except Yb in two environments, one surrounded by mere oxygen
> > (in precise oxygen-Hydrogen; due to disorder one may expect a single
> peak)
> > and another one in YbVO4 environment. With this info and for reasonable
> > fit, I have used two so2 as free parameters for N: one for first shell
> > (oxygen at two distances) and another for rest other shells. If I use
> > single so2, I obtain the value of around 0.92 with unsatisfactory fit
> > whereas the fit seems plausible with two so2 i.e., 0.75 and 2.2,
> > respectively. Using the same strategy, I could successfully fi!
> > t the nanoparticles again with large second so2 (1.79). From literature
> > and IFEFFIT earlier discussion, i understood that so2 should be between
> > 0.8-1.2 value. Here, I would like to know, does this huge second so2
> value
> > makes sense? is the obtained so2 value can be used to calculated
> > coordination number for unknown? Further, i have attached my worked files
> > with this message.
> > >
> > >
> > >
> > > Regards,
> > >
> > > Raj
> > >
> > > <YbVO4-bulk.fpj><YbVO4-nps.fpj>_____________________________
> > __________________
> > > Ifeffit mailing list
> > > Ifeffit at millenia.cars.aps.anl.gov
> > > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
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> > _______________________________________________
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> > End of Ifeffit Digest, Vol 167, Issue 2
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> ------------------------------
>
> Message: 2
> Date: Tue, 3 Jan 2017 15:45:37 -0500
> From: Bruce Ravel <bravel at bnl.gov>
> To: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> Subject: Re: [Ifeffit] Ifeffit Digest, Vol 167, Issue 2
> Message-ID: <d24675d6-264a-7850-54bd-109fe393b9bd at bnl.gov>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> On 01/03/2017 03:32 PM, Raj kumar wrote:
> > From XRD, it is confirmed that there is no side phase formation and
> > contamination. Hence, i guess the heavier element role could be avoided
> > here.
>
> Raj,
>
> While this might be true for your sample, in general, a statement like
> this always concerns me.
>
> From XRD, you can say is that there is no /crystalline/ side phase
> formation and that there is no contamination in the /diffracting/
> /portion/ of the sample.
>
> It is very common when preparing nanoparticulate matter for there to be
> non- or poorly-diffracting content in the sample. If that content
> contains the absorbing element, then it will have an impact on the XAS
> data.
>
> B
>
>
>
> --
> Bruce Ravel ------------------------------------ bravel at bnl.gov
>
> National Institute of Standards and Technology
> Synchrotron Science Group at NSLS-II
> Building 743, Room 114
> Upton NY, 11973
>
> Homepage: http://bruceravel.github.io/home/
> Software: https://github.com/bruceravel
> Demeter: http://bruceravel.github.io/demeter/
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 4 Jan 2017 12:38:05 +0100
> From: Raj kumar <rajrk37 at gmail.com>
> To: ifeffit at millenia.cars.aps.anl.gov
> Subject: Re: [Ifeffit] Ifeffit Digest, Vol 167, Issue 2
> Message-ID:
> <CACc-a9+EHP7bGjjpxW+cUp=9LzSZzKG=TvnM+gYVeR-T2g1yqQ at mail.
> gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Scott,
>
> I would like to add an extra point to the previous message. Yes, i am
> getting a large uncertainty for the second so2 (2.04 +/- 1.36).
>
> Regards,
> Raj
>
> On 3 January 2017 at 21:32, Raj kumar <rajrk37 at gmail.com> wrote:
>
> > Hi Scott,
> >
> > Thank you very much for your prompt response. EXAFS measurement was done
> > after the XRD characterization. From XRD, it is confirmed that there is
> no
> > side phase formation and contamination. Hence, i guess the heavier
> element
> > role could be avoided here.
> >
> > Split distances could be the reason??. The following is the method, i
> have
> > opted for modelling the obtained curve. Since YbVO4 is zircon structure,
> i
> > have constrained distance in paths 3, 8 and 9 with the pre-structural
> info
> > and let other distances vary with regular mathematical expression
> > alpha*Reff. am i doing wrong here? Before this, I have tried alpha*Reff
> for
> > all paths but fit failed miserably for multi-shells.
> >
> > Regards,
> > Raj
> >
> > On 3 January 2017 at 19:00, <ifeffit-request at millenia.cars.aps.anl.gov>
> > wrote:
> >
> >> Send Ifeffit mailing list submissions to
> >> ifeffit at millenia.cars.aps.anl.gov
> >>
> >> To subscribe or unsubscribe via the World Wide Web, visit
> >> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> >> or, via email, send a message with subject or body 'help' to
> >> ifeffit-request at millenia.cars.aps.anl.gov
> >>
> >> You can reach the person managing the list at
> >> ifeffit-owner at millenia.cars.aps.anl.gov
> >>
> >> When replying, please edit your Subject line so it is more specific
> >> than "Re: Contents of Ifeffit digest..."
> >>
> >>
> >> Today's Topics:
> >>
> >> 1. Re: Problem with large so2 (Scott Calvin)
> >>
> >>
> >> ----------------------------------------------------------------------
> >>
> >> Message: 1
> >> Date: Tue, 3 Jan 2017 09:59:18 -0600
> >> From: Scott Calvin <dr.scott.calvin at gmail.com>
> >> To: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> >> Subject: Re: [Ifeffit] Problem with large so2
> >> Message-ID: <3EF5E209-7681-49C6-9713-4BBF34C619A5 at gmail.edu>
> >> Content-Type: text/plain; charset="utf-8"
> >>
> >> Hi Raj,
> >>
> >> I haven?t looked at your files, but the kinds of results you are
> >> describing often indicate the model you are using beyond the first
> shell is
> >> incorrect. It may be that it has the wrong elements (e.g., heavier
> elements
> >> are present than what you modelled) or that the model includes split
> >> distances when in reality the compound is more symmetric.
> >>
> >> In short, no, the high second S02 does not make sense (although it would
> >> be good to know the uncertainties).
> >>
> >> Best,
> >> Scott Calvin
> >> Lehman College of the City University of New York
> >>
> >> > On Jan 3, 2017, at 9:38 AM, Raj kumar <rajrk37 at gmail.com> wrote:
> >> >
> >> > Dear All,
> >> >
> >> >
> >> >
> >> > I have been trying to fit EXAFS signal of YbVO4 both in bulk and
> >> nanoparticles form. Here, I would like to estimate so2 from bulk
> >> (reference) and subsequently use the number, as normalization
> parameter, to
> >> calculate the co-ordination number in all nanoparticles. Nanoparticles
> were
> >> synthesized by solution route. From our earlier understanding on the
> >> synthesis, in some cases, Yb may or may not completely involve in
> reaction.
> >> Therefore, I except Yb in two environments, one surrounded by mere
> oxygen
> >> (in precise oxygen-Hydrogen; due to disorder one may expect a single
> peak)
> >> and another one in YbVO4 environment. With this info and for reasonable
> >> fit, I have used two so2 as free parameters for N: one for first shell
> >> (oxygen at two distances) and another for rest other shells. If I use
> >> single so2, I obtain the value of around 0.92 with unsatisfactory fit
> >> whereas the fit seems plausible with two so2 i.e., 0.75 and 2.2,
> >> respectively. Using the same strategy, I could successfully fi!
> >> t the nanoparticles again with large second so2 (1.79). From literature
> >> and IFEFFIT earlier discussion, i understood that so2 should be between
> >> 0.8-1.2 value. Here, I would like to know, does this huge second so2
> value
> >> makes sense? is the obtained so2 value can be used to calculated
> >> coordination number for unknown? Further, i have attached my worked
> files
> >> with this message.
> >> >
> >> >
> >> >
> >> > Regards,
> >> >
> >> > Raj
> >> >
> >> > <YbVO4-bulk.fpj><YbVO4-nps.fpj>_____________________________
> >> __________________
> >> > Ifeffit mailing list
> >> > Ifeffit at millenia.cars.aps.anl.gov
> >> > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> >> > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
> >>
> >> -------------- next part --------------
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> >> ------------------------------
> >>
> >> Subject: Digest Footer
> >>
> >> _______________________________________________
> >> Ifeffit mailing list
> >> Ifeffit at millenia.cars.aps.anl.gov
> >> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> >> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
> >>
> >>
> >> ------------------------------
> >>
> >> End of Ifeffit Digest, Vol 167, Issue 2
> >> ***************************************
> >>
> >
> >
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