====== Relating trigonal crystal field parameters ($D_\sigma$ and $D_\tau$) to real space distortion ======
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asked by [[mailto:H.M.E.A.Elnaggar@uu.nl|Hebatalla Elnaggar]] (2019/06/19 12:12)
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Dear all,

I have simulated L-edge XAS data using trigonal distortion and was able to reproduce my spectra for a certain set of $D_q$, $D_\sigma$, and $D_\tau$. Now I am trying to understand what that implies in real space: Is the octahedron compressed or elongated and how much has the bond angles moved. I have checked Ballhausen but the trigonal distortion section is not very detailed. I was able to find only this paper regarding the issue: [[https://doi.org/10.1063/1.432116|J. C. Hempel, JCP 64, 11, p4307(1976)]] however the definitions of the angles are not very clear to me. Any suggestions on how to proceed with this?

Many thanks!
Heba  
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