FEFF10 simulation of Pt alloy
Dear all, I tried to use FEFF10 to simulate the XANES of Pt alloy (Pt L3 edge), and the simulation results fit the XANES collected using TFY mode. However, the white line intensity of the simulated XANES is much lower than the experiential spectra collected using HERFD mode. I wonder if there is way to fit the HERFD XANES results through simulation (in other words, to increase the white line intensity of the simulated XANES). Thanks a lot in advance! Best, Harry
Hello Harry:
I’m not sure how to help you with your specific question, but you might find this paper helpful.
High Energy Resolution Fluorescence Detection of the Pt L3, 2-Edge Whitelines of Pt-Based Bimetallic Systems: Implications for the Pt 5d5/2, 3/2 Density of States
Chen J, Finfrock Y, […] Sham T
The Journal of Physical Chemistry C (2021) 125(4) 2327-2333
Kind regards,
Shelly
From: Ifeffit
Dear Harry,
To a good approximation, using a decreased lifetime broadening works for
simulating HERFD-XANES. See https://doi.org/10.1021/jp063416t where
conventional and HERFD XANES are calculated with FEFF by decreasing the
broadening (Fig. 2). This is done in the EXCHANGE card, e.g. to decrease
the HWHM by 1.5 eV, apply on the 3rd number:
EXCHANGE 0 0.0 -1.5 -1
To use the default tabulated Pt L3 broadening (about 5 eV), use 0 (EXCHANGE
0 0.0 0 -1 )
Note: experimentally this is not entirely accurate, because in HERFD you
select the Pt L-alpha1 line, while in TFY you integrate over ~300 eV of
this line, taking all other transitions as well. For a detailed explanation
see https://doi.org/10.1016/j.cattod.2008.11.019 (Fig 2). But it should
represent the results pretty well.
Also note that specifically for Pt L3, the best match of the simulated
white line with experiment is obtained by ignoring the core-hole (assuming
its full screening), by applying the COREHOLE NONE card option. If this is
not done (COREHOLE FSR or RPA is used), the white line intensity is
strongly under-estimated, at least in Pt metal. See
https://doi.org/10.1023/A:1013849814153 for example and explanation.
Best regards,
Alexey
Am Mo., 16. Jan. 2023 um 12:45 Uhr schrieb Andy Zhang
Dear all,
I tried to use FEFF10 to simulate the XANES of Pt alloy (Pt L3 edge), and the simulation results fit the XANES collected using TFY mode. However, the white line intensity of the simulated XANES is much lower than the experiential spectra collected using HERFD mode.
I wonder if there is way to fit the HERFD XANES results through simulation (in other words, to increase the white line intensity of the simulated XANES).
Thanks a lot in advance!
Best, Harry _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
Dear all,
I appreciate your kind help! I followed your instructions and now the
simulation improves a lot! I will also follow the suggested papers
mentioned in the emails.
Have a nice day!
Best,
Harry
On Mon, Jan 16, 2023 at 4:11 PM Alexey Boubnov
Dear Harry,
To a good approximation, using a decreased lifetime broadening works for simulating HERFD-XANES. See https://doi.org/10.1021/jp063416t where conventional and HERFD XANES are calculated with FEFF by decreasing the broadening (Fig. 2). This is done in the EXCHANGE card, e.g. to decrease the HWHM by 1.5 eV, apply on the 3rd number: EXCHANGE 0 0.0 -1.5 -1
To use the default tabulated Pt L3 broadening (about 5 eV), use 0 (EXCHANGE 0 0.0 0 -1 )
Note: experimentally this is not entirely accurate, because in HERFD you select the Pt L-alpha1 line, while in TFY you integrate over ~300 eV of this line, taking all other transitions as well. For a detailed explanation see https://doi.org/10.1016/j.cattod.2008.11.019 (Fig 2). But it should represent the results pretty well.
Also note that specifically for Pt L3, the best match of the simulated white line with experiment is obtained by ignoring the core-hole (assuming its full screening), by applying the COREHOLE NONE card option. If this is not done (COREHOLE FSR or RPA is used), the white line intensity is strongly under-estimated, at least in Pt metal. See https://doi.org/10.1023/A:1013849814153 for example and explanation.
Best regards, Alexey
Am Mo., 16. Jan. 2023 um 12:45 Uhr schrieb Andy Zhang
:
Dear all,
I tried to use FEFF10 to simulate the XANES of Pt alloy (Pt L3 edge), and the simulation results fit the XANES collected using TFY mode. However, the white line intensity of the simulated XANES is much lower than the experiential spectra collected using HERFD mode.
I wonder if there is way to fit the HERFD XANES results through simulation (in other words, to increase the white line intensity of the simulated XANES).
Thanks a lot in advance!
Best, Harry _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
_______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
Hi Harry,
If you're calculating HERFD with FEFF, you have to suppress the
core-hole broadening, which will reduce the white line intensity.
This can be done by using a negative value of vi0 in the EXCHANGE card.
You can find the default value of the width in the header
files to xmu.dat.
If you have problems doing that, please send us your feff.inp and a
comparison with the expt data and we can troubleshoot.
With best wishes,
John
On Mon, Jan 16, 2023 at 3:45 AM Andy Zhang
Dear all, I tried to use FEFF10 to simulate the XANES of Pt alloy (Pt L3 edge), and the simulation results fit the XANES collected using TFY mode. However, the white line intensity of the simulated XANES is much lower than the experiential spectra ZjQcmQRYFpfptBannerStart This Message Is From an Untrusted Sender You have not previously corresponded with this sender. See https://itconnect.uw.edu/guides-by-topic/email-calendaring/protecting-your-e... for additional information.
Contact the UW-IT Service Center, help@uw.edu 206.221.5000, for assistance.
ZjQcmQRYFpfptBannerEnd Dear all,
I tried to use FEFF10 to simulate the XANES of Pt alloy (Pt L3 edge), and the simulation results fit the XANES collected using TFY mode. However, the white line intensity of the simulated XANES is much lower than the experiential spectra collected using HERFD mode.
I wonder if there is way to fit the HERFD XANES results through simulation (in other words, to increase the white line intensity of the simulated XANES).
Thanks a lot in advance!
Best, Harry _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov
https://urldefense.com/v3/__http://millenia.cars.aps.anl.gov/mailman/listinf... Unsubscribe: https://urldefense.com/v3/__http://millenia.cars.aps.anl.gov/mailman/options...
You also want to use COREHOLE None.
If the white line is still a bit low, you can shift the fermi level back by
about an eV or so:
CORRECTIONS 1.0 0.0
Cheers,
Josh
On Mon, Jan 16, 2023 at 10:38 AM John J Rehr
Hi Harry,
If you're calculating HERFD with FEFF, you have to suppress the core-hole broadening, which will reduce the white line intensity. This can be done by using a negative value of vi0 in the EXCHANGE card. You can find the default value of the width in the header files to xmu.dat.
If you have problems doing that, please send us your feff.inp and a comparison with the expt data and we can troubleshoot.
With best wishes, John
On Mon, Jan 16, 2023 at 3:45 AM Andy Zhang
wrote: Dear all, I tried to use FEFF10 to simulate the XANES of Pt alloy (Pt L3 edge), and the simulation results fit the XANES collected using TFY mode. However, the white line intensity of the simulated XANES is much lower than the experiential spectra ZjQcmQRYFpfptBannerStart This Message Is From an Untrusted Sender You have not previously corresponded with this sender. See https://itconnect.uw.edu/guides-by-topic/email-calendaring/protecting-your-e... for additional information.
Contact the UW-IT Service Center, help@uw.edu 206.221.5000, for assistance.
ZjQcmQRYFpfptBannerEnd Dear all,
I tried to use FEFF10 to simulate the XANES of Pt alloy (Pt L3 edge), and the simulation results fit the XANES collected using TFY mode. However, the white line intensity of the simulated XANES is much lower than the experiential spectra collected using HERFD mode.
I wonder if there is way to fit the HERFD XANES results through simulation (in other words, to increase the white line intensity of the simulated XANES).
Thanks a lot in advance!
Best, Harry _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov
https://urldefense.com/v3/__http://millenia.cars.aps.anl.gov/mailman/listinf... Unsubscribe: https://urldefense.com/v3/__http://millenia.cars.aps.anl.gov/mailman/options...
participants (5)
-
Alexey Boubnov
-
Andy Zhang
-
John J Rehr
-
Joshua Kas
-
Kelly, Shelly Diane