[Ifeffit] P K-edge EXAFS

[Mike Massey]

In my experience the main difficulties with EXAFS on P (phosphate) come from two factors (not signal to noise, it's not hard to get a nice smooth line, but):

1) You've got 4 O atoms, guaranteed, so any other signal will be small and on top of that very strong signal generated from the first-neighbor O

Unfortunately,

2) You have very limited data range, either due to instrumental limitations, or due to interference from sulfur

Don't get me wrong I still have some data sitting around and I'd love to try P EXAFS analysis on it just to try and grasp that brass ring but...It's not the easiest task ever.

If you want good data quality "scan longer" is always an option. Some might think it's crazy but I do think I have some P XAS data where I took 30 or 60 scans, maybe overnight or something. The scans are so short that repeats are easy.


Hope this commentary is helpful.



Mike




> On Sep 14, 2023, at 07:04, Marcelo Eduardo Alves <mealves at gmail.com> wrote:
> 
> 
> Hi there,
> 
> I begin by examining phosphorus adsorption by goethite, hematite, and gibbsite.
> 
> Why is it difficult, if not impossible, to obtain EXAFS spectra at the P-K edge that can be properly used, i.e., spectra with a high signal-to-noise ratio, especially for dilute samples?
> 
> Would it be possible to use arsenic as a phosphorus proxy to get conclusions from As K-edge EXAFS data that could be extended to P?
> 
> Thank you.
> 
> 
> 
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