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forum:data:2023:directional_x-ray_spectroscopy_potential_bug [2023/04/08 00:10] – Charles Cardotforum:data:2023:directional_x-ray_spectroscopy_potential_bug [2023/04/08 01:00] (current) – Charles Cardot
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 I have been experimenting with calculating direction dependent x-ray emission using Quanty and the DFT+MLFT framework. However, I seem to be running into an issue with the mean field operators calculated from the Tight Binding (TB) object. I have been experimenting with calculating direction dependent x-ray emission using Quanty and the DFT+MLFT framework. However, I seem to be running into an issue with the mean field operators calculated from the Tight Binding (TB) object.
  
-The directional dependence is encoded in the DFT step, where I distort the crystal lattice slightly (~1%) along a particular axis. When I stretch along the a-axis I get an tight binding Hamiltonian, HDFT, that looks like+The directional dependence is encoded in the DFT step, where I distort the crystal lattice slightly (~2%) along a particular axis.
  
-a_stretched_HDFT: https://drive.google.com/file/d/1_pMPkm1Pxw_f7F8whgx8hkA1boeQX_5-/view?usp=share_link+   # lattice constants; 
 +   @l@ 4.27633759 4.18633759 4.18633759 
 +   # set axis angles 
 +   @a@ 90. 90. 90. 
 +   # setup Wyckoff positions 
 +   @n@2 
 +   # Now, give list of ALL !!! Wyckoff positions. 
 +   @1@ Ni @ 0.00000000  0.00000000  0.00000000 
 +   @2@ O  @ 0.00000000  0.00000000  0.50000000 
 + 
 + 
 +When I stretch along the a-axis and go through the regular Wannierization process to create a tight binding Hamiltonian, I get an HDFT that looks like 
 + 
 +a_stretched_HDFT: https://drive.google.com/file/d/1sE72v2rbbPM9Bof4Hg_CgNgvqmtjKjYY/view?usp=share_link
  
 which makes sense in the context of the distorted octahedral crystal field. The //xy// and //xz// orbitals are still degenerate, while the //yz// is now lower energy. Also the //z^2-r^2// and //x^2-y^2// orbitals become mixed. The MLFT calculation within Quanty proceeds much the same way as described in the 2022 and 2019 Heidelberg tutorials for DFT + MLFT, where the mean field components Coulomb interaction is subtracted from HDFT to avoid double counting. The full code that I am running can be found here (https://drive.google.com/drive/folders/1G0iSTfIMT8i39CWWg1StEs5Kj26ZYQ1W?usp=share_link), but an excerpt is shown below. which makes sense in the context of the distorted octahedral crystal field. The //xy// and //xz// orbitals are still degenerate, while the //yz// is now lower energy. Also the //z^2-r^2// and //x^2-y^2// orbitals become mixed. The MLFT calculation within Quanty proceeds much the same way as described in the 2022 and 2019 Heidelberg tutorials for DFT + MLFT, where the mean field components Coulomb interaction is subtracted from HDFT to avoid double counting. The full code that I am running can be found here (https://drive.google.com/drive/folders/1G0iSTfIMT8i39CWWg1StEs5Kj26ZYQ1W?usp=share_link), but an excerpt is shown below.

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