[Ifeffit] Ifeffit Digest, Vol 158, Issue 3

[Matt Newville]

On Sun, Apr 3, 2016 at 6:56 PM, Matteo Busi <basebush at gmail.com> wrote:

> 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))
>


Wouldn't using bkg(E) suppress the fine-structure you are trying to
recover?  Anyway what are the units, are you normalizing bkg(E) to
something meaningful?  I would suggest using data from Chantler or
Cromer-Liberman here.   Or perhaps match mu(E) or bkg(E) to these.


> μo = μ(E) : photoelectric total linear absorption coefficient of the
> sample at incident energy E
>                    - I used the xmu(E) for this
>

Again, be mindful of what the units are.


> 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)
>

I am pretty sure that this is not what you want.  You probably want mu(E)
at the Cu fluorescence energy (8.046  keV). This can make a significant
difference.

HTH,

--Matt
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