Re: [Ifeffit] Shifted data in Athena

Hello, I am writing with a way to reproduce the shift that I previously reported between data and reference, which I suspect is the result of a bug in Athena Demeter 0.9.15. Attached are two data files and two screen shots. 1. open Athena 2. from the file menu choose import data 3. select the file Co_016.dat and click open 4. select the columns as shown in Load016ScreenShot.png and click OK 5. from the file menu choose import data 6. select the file Co_228.dat and click open 7. select the columns as shown in Load228ScreenShot.png and click OK. The data imported from Co_228.dat will display the shift between data and reference. Repeating steps 5-7 will import the data without applying a shift. Comparing the first import of Co_228.dat to subsequent imports shows that the reference spectrum is shifted on the first import of this file. Thank you, George On Fri, Mar 8, 2013 at 11:43 PM, George Sterbinsky < GeorgeSterbinsky@u.northwestern.edu> wrote:

Hello,

In attempting to reproduce the steps that I performed before I noticed the shift, I am now unable to deglitch the data, and obtain the attached error instead. I'm not certain this is related to the shift, but it may be.

If anyone is interesting in attempting to reproduce the steps to obtain this message on their own system, let me know and I will send you the project and instructions.

Thank you, George

On Fri, Mar 8, 2013 at 9:48 PM, George Sterbinsky < GeorgeSterbinsky@u.northwestern.edu> wrote:

...

Hi Anatoly,

I've checked with other software and the shift is not present. You can also tell the shift has some other origin by choosing to show data points in the preferences. This way you can see the data points do not match in energy, as one might expect for data and a reference. This can also been seen by looking at the beginning and ending of the spectra, which begin and end at different energy. Also, note the energy shift parameter for both groups is set to zero.

Thank you, George

On Fri, Mar 8, 2013 at 9:25 PM, Anatoly I Frenkel wrote:

...

Maybe the shift is real due to chemical shift of the sample relative to reference material?

Sent from my mobile phone, please forgive typos

----- Reply message ----- From: "George Sterbinsky" To: "XAFS Analysis using Ifeffit" Subject: [Ifeffit] Shifted data in Athena Date: Fri, Mar 8, 2013 9:15 PM

Hello,

I have attached an (D)Athena project with containing two groups, imported as a primary data set and a reference. The groups were therefore imported on the same energy grid. However, when plotted, the energy values of the data points for the two groups are clearly shifted with respect to each other. Can someone please explain the origin of this shift?

Thank you, George

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