[Ifeffit] FEFF10 simulation of Pt alloy

[Andy Zhang]

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 <alexeyboubnov at gmail.com>
wrote:

> 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 <hzhangcat at gmail.com
> >:
>
>> 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
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