Use of Magmom when l is not zero

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KWH
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Use of Magmom when l is not zero

#1 Post by KWH » Fri May 08, 2026 7:08 pm

I am confused the proper choice for magmom. Is it based solely on unpaired spins or is it the spin plus orbital angular momentum (sum of l+2s). That is, if I have one unpaired electron in an s orbital magmom = 1, but what is it for an unpaired electron in a p or d orbital?


martin.schlipf
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Re: Use of Magmom when l is not zero

#2 Post by martin.schlipf » Fri May 08, 2026 8:14 pm

MAGMOM is only the initial guess for the spin component. During an iteration the density will be updated to find the ground state. If you set LORBIT you can read the final spin magnetic moments. To compute the orbital moments you need to set LORBMOM as well (note that this requires spin-orbit coupling LSORBIT).
Furthermore keep in mind that the magnetic moments are only defined in a sphere around the atom so the sum of all magnetic moments is not equal to the magnetization because there may be some density in the interstitial region.

Martin Schlipf
VASP developer


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