[Ifeffit] EXAFS of solid-solution alloy

mike massey mmassey at gmail.com
Fri Feb 8 10:40:50 CST 2019


A couple of thoughts...

A) If I were approaching a problem like this, I would probably prepare a
series of samples with different ratios, and look for trends in the fits.
If you see consistent differences across the series, in the same direction,
you can probably be more confident in the resulting fits, and in your
conclusions.

B) This problem seems like it might be a good application of a wavelet
transform for analysis. I've been meaning to do some wavelet analysis
myself, but haven't gotten around to it, so I can't offer specific
advice...But perhaps someone on the list can.


Cheers,



Mike









On Fri, Feb 8, 2019 at 2:37 AM Chongchong Mellon <mellonchongchong at gmail.com>
wrote:

> Hi all,
>
>  I have some problems in analyzing the EXAFS of solid-solution alloy, let
> us define as A0.5B0.5. I have searched the mailbox but cannot find
> similar discussion yet. So I post the question here and hope to get some
> suggestion from you.
>
>
>
>    1. A and B are immiscible metals from the phase diagram, which means
>    that I couldn’t get the bulk A0.5B0.5 as a standard reference. In this
>    case, how can I estimate the amp for the K-edge of A or B?
>    2. A and B are very near (atomic number B-A = 2) in the periodic
>    table. So their lattice parameters are quite close to each other. In this
>    case, when I tried to fit the 1st shell use A-A and A-B paths at the same
>    time, the Happiness parameter becomes worse and the coordination number of
>    A-B is not realistic (large errors!).  If I fit with only the A-A path
>    or A-B path, I get a good fit. However, atomic resolution STEM-EDX maps
>    show the homogenous distribution of both A and B atoms. The A-A and A-B
>    bond might have an equal ratio. In this case, how can I do the fitting?
>
>
> Thank you very much in advance!
>
>
> Sincerely,
>
> Chong
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