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For a slab calculation adding dipole correction. If I don't set the tag 'DIPOL', VASP determines where the charge density averaged over one plane drops to a minimum. But I can only find it in vasprun.xml, <v name="DIPOL"> -100.00000000 -100.00000000 -100.00000000</v>. Why it's showing this value not actual position?
Is it possible to find exact location in this case?
If I set DIPOL by ourself, like DIPOL = 0.5 0.5 0.5, then we can find it in vasprun.xml, with 0.5 0.5 0.5 in this entry.
Note that DIPOL in vasprun.xml refers to the INCAR tag.
If none was specified, then a value of -100 -100 -100 is used by default, which means that the center w.r.t which the dipole is computed is determined automatically.
You can always read the position from the OUTCAR by looking for:
direction 1 min pos XXX
direction 2 min pos YYY
direction 3 min pos ZZZ
Note that it's possible that only one of these lines appears, depending on the value of https://www.vasp.at/wiki/index.php/IDIPOL
The numbers XXX, YYY, ZZZ refer to coordinates of the point in the charge density in real space.
To check how many points you have in each direction, you just need to look in the OUTCAR for:
dimension x,y,z NGXF= NGYF= NGZF=
To compute the actual coordinate, it should just be a matter of taking XXX/NGXFA, YYY/NGYFB or ZZZ/NGZF*C