[Ifeffit] The difference of EXAFS oscillation when using Athena and when using Larch

[Yuji Mahara]

Dear All,



I am Yuji Mahara at Nagoya University, Japan.



I am using Athena in Demeter 0.9.24 package and Larch 0.9.33 on windows 10.

At that time, I am worrying about the difference of EXAFS oscillation when
using Athena and when using Larch.



k3-weighted Pd K-edge EXAFS and Fourier transform EXAFS spectrum for PdO
bulk are shown in attached file(PdO.png).

When XAFS raw data is read using Athena and EXAFS oscillation is obtained,
EXAFS spectrum is smooth and noise is small. On the other hand, using Larch,
noise is noticeable in k space.

This phenomenon occurred when analyzing other XAFS data as well.



I tried to analyze XAFS data by Athena and Larch with the almost same
conditions.

Does this difference of EXAFS results arise from the difference in autobk's
algorithm between Athena and Larch?



The analysis conditions are shown below.

If someone knows this reason, please let me know.



Best regards,



Yuji Mahara

******************************************
■ Yuji Mahara
Nagoya University(Japan)  D3
Graduate School of Engineering
Furo-cho, Chikusa-ku, Nagoya-shi, Aichi, 466-8603, Japan
・Phone :  <tel:%2B81-52-789-3192> +81-52-789-3192
・E-mail :  <mailto:mahara.yuji �� e.mbox.nagoya-u.ac.jp>
mahara.yuji �� e.mbox.nagoya-u.ac.jp
******************************************



#####Analysis condition of Athena #####



e0 -->[ set e0 to a fraction of the edge step] --> 24355.9037323484

Normalization order: 3

Pre-edge range: from -150 to -60 eV

Normalization range: from 150 to 1100 eV

Rbkg: 1

k-weight used by spline: 2

Spline clamp: low=None, high=Strong

Spline range in k: from 0 to 17

Fourier transform k-range: from 3 to 15, dk=0.5, window=’hanning’



#####Analysis condition of Larch #####



dat.e0 = 24355.9037323484 <-- e0 was estimated by Athena

pre_edge(dat.e, dat.mu, group=dat, e0=dat.e0, pre1=-150, pre2=-60,
norm1=150, norm2=1100, nnorm=2, _larch=mylarch)

autobk(dat.e, dat.mu, group=dat, e0=dat.e0, rbkg=1, nclamp=5, clamp_lo=0,
clamp_hi=24, kstep=0.05, kmin=0, kmax=17, kweight=2, win='hanning',
_larch=mylarch)

xftf(dat.k, dat.chi, group=dat, kmin=3, kmax=15, dk=0.5, window='hanning',
kweight=3, _larch=mylarch)



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