[Ifeffit] Problem with Hephaestus at Ca L-edges (Matthew Marcus)
Jana Padeznik Gomilsek
jana.padeznik at um.si
Thu Sep 24 01:49:23 CDT 2015
It is very hard to measure or to calculate absolute absorption data,
especially in the
vicinity of the absorption edges and especially in the soft x-ray
region. Therefore there
are significant differences between the tables and I think nobody knows
which
are better.
Chantler, for example, says the expected uncertainties of the tables in
your region are
50 % to 100 %
(http://physics.nist.gov/PhysRefData/FFast/Text2000/sec06.html#tab2).
I would doubt the Chantler's L3+.1 number, all other numbers look ok -
this is what you
can get.
jana padeznik gomilsek
> Message: 3
> Date: Wed, 23 Sep 2015 18:02:08 -0700
> From: Matthew Marcus<mamarcus at lbl.gov>
> To: XAFS Analysis using Ifeffit<ifeffit at millenia.cars.aps.anl.gov>
> Subject: [Ifeffit] Problem with Hephaestus at Ca L-edges
> Message-ID:<56034B90.70405 at lbl.gov>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> I wanted to work out the edge-jump ratio between the L3 and L2 edges of Ca using Hephaestus. I ran into two problems:
>
> 1. The ratio implied by what it says for the unit-edge-step thickness does not agree with that derived by computing the absorption (cm^2/gm) above and below each edge and
> dividing the difference (L3+ - L3-)/(L2+ - L2-).
>
> 2. The results differ wildly depending on which resource I use:
>
> L3-.1 L3+.1 L2-.1 L2+.1 (L1+ - L1-)/(L2+ - L2-)
> Elam 4759.796 27837.796 27478.018 38434.277 2.106375908
> Chantler 4322.6 6547.121 32827.61 35436.543 0.852655473
> Cromer-Leiberman 4288.524 33471.375 32786.294 47072.991 2.042659055
>
> The Henke table doesn't yield an L2 edge jump at all, while the Shaltout yields the same results as Cromer-Leiberman. Which one should I trust and why?
>
> This is old-style H. (V0.18), not Demeter.
> mam
>
>
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