Dear fleur developers,

It would be very interesting if we can calculate Mossbauer parameters, isomer shift, electric field gradient, and hyperfine field(with different contributions output separately, contact field+orbital+dipole field).

Best,
Zhiwei

Dear fleur developers,

It's been a year since my last check, I just want to see what is the status now? Is there anyone working on this problem?

Thanks for your wonderful work!

Zhiwei

Dear Gregor,

Thank you for putting this into fleur. We do need the following three parts:
1) The isomer shift, in fact this is related to the s-electron density (Isomer shift = a * density) at the nucleus and the proportion constant, a, is materials relevant. Therefore, the output should be just the corresponding s-electron density I think.
2) The quadrupole splitting is related to the electric field gradient. In this case, the electric field gradient is enough.
3) the magnetic hyperfine field.

In understanding the calculated numbers, it is good to know different contributions to these quantities. Therefore, it would be nice that the output contains the total results and also how much contributions from different physical orgins.

Best,
Zhiwei

Dear Gregor,

I found these notes from wien2k website which might be helpful. There, they have some notes on how they implemented the calculations of EFG and hyperfine field.
ww.wien2k.at/reg_user/textbooks/

Also these papers might help
journals.aps.org/prb/abstract/10.1103/PhysRevB.35.3271
journals.aps.org/prb/abstract/10.1103/PhysRevB.81.174412

best,
Zhiwei

Dear Gregor,

Sorry for this late reply.

Thank you very much for this good news. The shell-resolved output should be fine I think.

one more thing, please can you write a short explanation on how to use this feature, because I could find any tutorial on this subject on the website of fleur.
For example, make a short example on some simple systems from which we can learn how to calculate these parameters that we measure with experiments.

Best,
Zhiwei

Dear Gregor,

Thanks for the info. I made a simple calculation of Fe with default settings.
To activate the hyperfine field calculation kcrel was setted to "1"
However, I got the following results in the file of OUT: see what follows.
It seems that the calculated Hyperfine field is: -643.473 kG when compared to the experimental value of ~340 kG this is not OK.
To me, it looks like (3s1/2) electron is not treated as core electrons which it should be I think.
However, when I changed the electron configuration in the input file, some err happened. I am still trying to fix this.

best,
Zhiwei

MUE KAP ITER ENERGY (Hart) HF (KG)
1s1/2 -1/2 -1 3 -256.5470723
1s1/2 1/2 -1 3 -256.5475614
1s -5.349
2s1/2 -1/2 -1 3 -29.5370218
2s1/2 1/2 -1 3 -29.4877801
2s -639.931
2p3/2 -3/2 -2 3 -24.9233138
2p3/2 -1/2 -2 3 -24.9101239
2p1/2 -1/2 1 4 -25.3578354
2p3/2 1/2 -2 3 -24.8976487
2p1/2 1/2 1 4 -25.3699574
2p3/2 3/2 -2 3 -24.8857818
2p 1.806
HFTOT: -643.474