Re: [Ifeffit] Problem with Hephaestus at Ca L-edges (Matthew Marcus)

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 To: XAFS Analysis using Ifeffit Subject: [Ifeffit] Problem with Hephaestus at Ca L-edges Message-ID:<56034B90.70405@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