[Ifeffit] Shifted data in Athena

George Sterbinsky GeorgeSterbinsky at u.northwestern.edu
Wed Mar 27 10:51:23 CDT 2013


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 at 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 at 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 <afrenke2 at yu.edu>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" <GeorgeSterbinsky at u.northwestern.edu>
>>> To: "XAFS Analysis using Ifeffit" <ifeffit at millenia.cars.aps.anl.gov>
>>> 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
>>>
>>> _______________________________________________
>>> Ifeffit mailing list
>>> Ifeffit at millenia.cars.aps.anl.gov
>>> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>>>
>>>
>>
>
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