[Ifeffit] Ifeffit Digest, Vol 158, Issue 3

[Matteo Busi]

Hi Bruce,
Thanks for your help, it's really appreciated.
I was trying to keep it simple but it seems I'm just messing around.

What I am trying to do is to perform a new developed self-absorption
correction using collected fluorescence absorption coefficient data on a
CuSO4 (pentahydrate) capillar (cylinder) and spherical sample with Cu as
absorber, having different values of molarity and penetration depth.
The correction expression requires these measured quantity:
μX(E) : the absorption coefficient due to a given core excitation of the
absorbing atom
              - I used the background function for this ( bkg(E))
μo = μ(E) : photoelectric total linear absorption coefficient of the sample
at incident energy E
                   - I used the xmu(E) for this
μh = μ(E) :photoelectric total linear absorption coefficient of the sample
at fluorescence emission Ef
                   - I used the xmu(Ef) with Ef the K absorption edge of Cu
( 8.9789 eV)
χ: and here I used the chi(E) values of the exported ascii .xmu file

Hope it's clear now.
Matteo


2016-04-02 19:00 GMT+02:00 <ifeffit-request at millenia.cars.aps.anl.gov>:

> 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: Ifeffit Digest, Vol 158, Issue 1 (Matt Newville)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 1 Apr 2016 15:56:29 -0500
> From: Matt Newville <newville at cars.uchicago.edu>
> To: XAFS Analysis using Ifeffit <ifeffit at millenia.cars.aps.anl.gov>
> Subject: Re: [Ifeffit] Ifeffit Digest, Vol 158, Issue 1
> Message-ID:
>         <CA+7ESbrsbsFQGMGLwGNPJmVO=
> fGzksbv1SezR3M5pRkXanNyDg at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Matteo,
>
>
> On Fri, Apr 1, 2016 at 8:35 AM, Matteo Busi <basebush at gmail.com> wrote:
>
> > Hi Bruce,
> > Now this is clear.
> > In my case the correction I have to perform requires these
> > measured/evaluated parameters: chi, mu (not sure if it's better to work
> > with normmu here) and the background function.
> > Is it physically meaningless to have the mu(k) and bkg(k) data? If that
> is
> > not the case I would like to have these two columns exported in the ascii
> > chi(k) file.
> > So then I can perform the correction and re-import the new corrected
> > chi(k) and make comparison with the uncorrected.
> >
> > Kind regards,
> > Matteo
> >
> >
> It would certainly help (and by that I mean "help you get the answers
> you're looking for") if you gave us more details about what you're trying
> to do rather than ask for how to what you think you want to do.
>
> Just to be clear: Converting from E to k does not involve a Fourier
> transform, just
>    k = sqrt((2m*e/hbar**2)*(E-E0))
>
> for k in Ang^-1 and E in eV, that's  k ~= sqrt(0.262468*(E-E0))
>
> I'm not sure what you're trying, but I would image you want to use
> normalized mu(E) or at least pre-edge subtracted mu(E).  That is, what we
> call mu(E) is typically really -ln(I/I0)
> where I and I0 are not the actual intensities before and after the sample,
> but counts or counts per time in some detector that samples the flux.
> These values include more or less arbitrary scale factors (amplifier gains,
> etc) included.  That means that (unless you very careful) mu(E) does not
> have meaningful units, certainly not cm^-1 or cm^2/gram.
>
> Normalized mu(E) doesn't have such units either, but it's an easier place
> to start.
>
> --Matt
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20160401/658d433a/attachment-0001.html
> >
>
> ------------------------------
>
> 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 158, Issue 3
> ***************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20160404/56ff6153/attachment.html>