[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 
are better.
Chantler, for example, says the expected uncertainties of the tables in 
your region are
50 % to 100 % 
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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