Regarding the incorporation of charged ions

[chandan_kumarvishwakarma1]

Dear users
I am trying to incorporate/dope a charged ion (e.g. Li+) in a complex organic
system. For this, I tried NELECT tag by removing one electron from the
total valance electrons. Using this tag we can remove an electron from the
whole system but I just want to remove one electron from the Li only, so
that it becomes Li+.
Please suggest me, how can I incorporate charged atoms/ions??

---
Chandan

[henrique_miranda]

What you mean by removing an electron from Li only?
If you mean removing a valence electron and this electron is at the same energy as other electrons in the system then NELECT is the right way to go.
If you mean an electron that that is mostly localized near the Li ion and has energy below all the other electrons in your system (sometimes called a semi-core electron) then the best approach might be to use a POTCAR that treats this electron in the core and use the ICORELEVEL approach.

There is also this third-party package available that might be closer to what you require:
https://github.com/WatsonGroupTCD/Occup ... ol-in-VASP
but in this case, we cannot provide support for it.

If you are referring to core electrons, then I believe you already started a thread asking this question:
https://www.vasp.at/forum/viewtopic.php?t=17936
If something was not clear in my answer in that thread I ask you that we please continue the discussion there.

[chandan_kumarvishwakarma1]

I got your point.

Thanks for your reply.
Chandan

[henrique_miranda]

There is one other option that I've forgotten to mention: using ISMEAR=-2 together with FERWE and FERDO (for the case of spin-polarized calculations).
Note however that in this case the occupations are kept fixed during the SCF cycle which is only reasonable for a certain type of calculations.

I leave here the links for the relevant documentation:
https://www.vasp.at/wiki/index.php/ISMEAR
https://www.vasp.at/wiki/index.php/FERWE
https://www.vasp.at/wiki/index.php/FERDO