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Partial charge density

Posted: Wed Dec 07, 2022 9:05 am
by IBRAHIM
Dear All,

I would like to understand the effect of using LORBIT = 11 together with ISYM =2 in vasp5:

It is written on vasp wiki "For LORBIT >= 11 and ISYM = 2 the partial charge densities are not correctly symmetrized and can result in different charges for symmetrically equivalent partial charge densities. This issue is fixed as of version >=6"

Yes, I checked OUTCARs from vasp5.4.4 and vasp6.2.0. vasp6.2.0 gives equivalent charges for symmetrically equivalent partial charge densities and vasp5.4.4 gives slightly different values. However, by checking density of states, look same with both versions.

So, what is the effect of using LORBIT = 11 together with ISYM =2 in vasp5 on partial DOS calculation or charge calculations such as charge density, charge transfer?
Should we switch to ISYM=0 in these cases? or what we should take care about?

Best regards,
Ibrahim

Re: Partial charge density

Posted: Wed Dec 07, 2022 9:47 am
by IBRAHIM
Also, for some 2D systems, the partial charge density written in outcar are symmetrically equivalent with both versions.

Re: Partial charge density

Posted: Mon Dec 12, 2022 11:45 am
by ferenc_karsai
The error in VASP version<6 is always there but don't always show themselves.
The extent is fully case dependent.
So to be on the safe side, I would follow the advises on wiki (first ISYM=2 and then recalculate with ISYM=0) for VASP version <6.

Re: Partial charge density

Posted: Mon Dec 12, 2022 1:01 pm
by IBRAHIM
Thanks for your reply.

Would this error only relate to the printed information in OUTCAR "partial charge density and partial magntization"?

Or it affects also on other calculated properties such as partial density of states, electron transfer, charge density difference, and so on?

Re: Partial charge density

Posted: Mon Dec 12, 2022 2:19 pm
by ferenc_karsai
I think every quantity that uses local symmetries should be affected by the bug.

So it's safer you always use the workaround for VASP <6 or better upgrade to the latest version since versions <6 are not maintained by us.