Good Morning.
Iv'e made Fe K-edge XAS measurements on a mineral with Fe3+ and Fe2+ atoms, looking for the pre-edge feature and using gaussian curves to fit the pre-edge assuming 4 quadrupole transitions: 2 for Fe2+, 2Fe3+. Obviusly, each transitions has an excitation state lifetime, of 1.5eV from literature, which i have assumed to be the same for each absorbing atom.
My question is: Can the temperature (even 800°C) alter this lifetime? If it changes, does it equally changes? The lifetime can be altered also by the oxidation state of the absorbing atom?
ps: naturally, what i wonder is if the alterations is more than 5/10 % than the original.
Edit: the sample is a natural riebeckite crystal, measured from 270°C to 800°C continuosly, with normal atmosphere conditions.
Hi Federico:
interesting question.
I would add a question but not an answer.
If there is observable change in the life time, you may see it in the broadening of of those absorption features, is that your case?
I suggest the following paper
https://www.sciencedirect.com/topics/engineering/high-temperature-oxidation
Yimin Mijiti You are absolutely right, becouse we see the broadening in the pre-edge feature. However, i was wondering what could be the cause, due to the fact that the pre-edge depends also on the asimmetry of the absorbing atom's neightbours.
Artur Braun Thanks for your suggestions. I've added the required informations.
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