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

[Matthew Marcus]

I'm not after absolute data, just the edge-jump ratio.  This would have to be extracted by peak+arctan fitting because any spectra will have peaks and a very limited
range between edges.  If the Chantler numbers are incorrect, then perhaps the edge-jump ratio is really 2.

Do you have a reference which can be cited?

I'll try the CXRO tool next, since CXRO specializes in soft X-rays.
	mam

On 9/23/2015 11:49 PM, Jana Padeznik Gomilsek wrote:
> 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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