I want to calculate the band structure and RPA absorption spectrum of ferromagnetic Ni where one of the atom has a core-hole. For this purpose is it sufficient to create a super-cell with one of the Ni atom replaced with a new species where one of the elctron is removed from a core state (setting its occupancy to 1 instead of 2) and adding an electron to the super cell as a background charge?
Any advice would be greatly appreciated
Zuanni
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yes, that's how you can do it. You could also just add the missing electron to the valence states in the species file - it does not matter to which, as this will be redistributed during the SCF run.
However, you should be aware that the spectrum does vary with the orbital you choose and this is not equivalent to having the core hole on the orbital of the initial absorption state. The latter is however not possible in elk, because you can not enforce an occupation for the valence orbitals.
You might instead consider a BSE calculation, which is certainly more accurate than the core-hole calculation. Obtaining a well-converged spectrum is not so easy, though and you have no access to the band structure.
Good luck,
Markus
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Dear all,
I want to calculate the band structure and RPA absorption spectrum of ferromagnetic Ni where one of the atom has a core-hole. For this purpose is it sufficient to create a super-cell with one of the Ni atom replaced with a new species where one of the elctron is removed from a core state (setting its occupancy to 1 instead of 2) and adding an electron to the super cell as a background charge?
Any advice would be greatly appreciated
Zuanni
Dear Zuanni,
yes, that's how you can do it. You could also just add the missing electron to the valence states in the species file - it does not matter to which, as this will be redistributed during the SCF run.
However, you should be aware that the spectrum does vary with the orbital you choose and this is not equivalent to having the core hole on the orbital of the initial absorption state. The latter is however not possible in elk, because you can not enforce an occupation for the valence orbitals.
You might instead consider a BSE calculation, which is certainly more accurate than the core-hole calculation. Obtaining a well-converged spectrum is not so easy, though and you have no access to the band structure.
Good luck,
Markus