Hi Matt,

  I think the “turn of the pre-edge baseline” option would be useful in cases like mine where one would like to plot the “experimental” E(k) as well as its Fourier transform. If it’s easy to do, why not offer a checkbox to run off the pre-edge subtraction?  In any case, thanks for thinking about the problem.

Cheers,

              Paul

From: Ifeffit <ifeffit-bounces@millenia.cars.aps.anl.gov> on behalf of Matt Newville <newville@cars.uchicago.edu>
Reply-To: XAFS Analysis using Ifeffit <ifeffit@millenia.cars.aps.anl.gov>
Date: Tuesday, January 29, 2019 13:21
To: XAFS Analysis using Ifeffit <ifeffit@millenia.cars.aps.anl.gov>
Subject: Re: [Ifeffit] Plotting flattened feffit simulation results

Hi Paul, 

On Mon, Jan 28, 2019 at 2:57 AM FonsPaul <paul-fons@aist.go.jp> wrote:

Hi All,

  I have a rather simple question and a reply for either Larch or athena would be welcome.  I have calculated a number of structures using DFT and have run feff on each of the appropriate sites and have then averaged the E(k) results.  I have no problem reading in the data to athena, however, due to the lack of a pre-edge baseline, it is typically not possible to choose a reasonable “pre-edge” baseline so that I can plot the data for the different structures in “flattened” mode. The “post-edge” baseline works very well with the default values (as there is literally no noise in the spectra).  My question is how can I induce athena to plot the E(k) data for the different structures in “flattened” mode. Ultimately, I will end up taking a Fourier transform into real space so I would also like to have a proper baseline so I can compare intensities as well.  In effect, the data from feff9 is already normalized.  Thanks for any suggestions!

Sorry for the trouble. Perhaps we should add a routine that adds a more realistic preedge to the Feff XANES calculations, so that the "normal" pre-edge and normalization steps work better?   I would think that simply add a segment of 0s for value below the main edge might wok well enough.....   That would be easy enough to do....

--Matt