[Ifeffit] Standardized Spectra

[Matt Newville]

Hi Kyle,

On Sun, Aug 7, 2022 at 8:15 PM Kyle Draim <kad141 at georgetown.edu> wrote:

> Hello!
>
> I don't have any X-Ray data to analyze in your app, I'm just seeking a
> visual display of each element's standardized/accepted X-Ray spectra
> (instead of a table of numbers). So far, I've downloaded the application,
> but I'm stuck on how to find this information.
>

"X-ray data" and "X-ray spectra" are somewhat ambiguous.   In my
experience, the generic "X-ray data" often implies X-ray fluorescence
spectra, X-ray powder diffraction data, or an X-ray astronomy instrument
(say, Chandra).

We're mainly dealing with X-ray absorption spectroscopy (XAS) data here.
But if you want "X-ray spectra" for each element, that may not really mean
XAS, which will depend not only on the element but also on its atomic
environment.

Anyway, for XAS data, there are some example data included with the
software we use, see

https://github.com/xraypy/xraylarch/tree/master/examples/xafsdata, and
https://github.com/bruceravel/demeter/tree/master/examples/data

There are also online databases of experimental spectra at

https://xaslib.xrayabsorption.org/, and
https://mdr.nims.go.jp/

(FWIW, I would not recommend the data at the Lytle database - these data
files are hard to turn into usable spectra, and the quality is spotty.)

There are also calculations of predicted XAS spectra for some materials at
https://next-gen.materialsproject.org/xas.

To be clear, all of these spectra are represented by tables of numbers...
which kind of leads me back to thinking you might not be asking about XAS
data.

Anyway, I hope that helps,

--Matt
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