FERWE
FERWE = [real array]
Description: FERWE sets the occupancies of the states for ISMEAR=-2.
To set the occupancies, specify
FERWE = f(1) f(2) f(3) ... f(NBANDS×Nk)
The occupancies must be specified for all bands and k points. The band index runs fastest. The occupancies must be between 0 and 1.
The occupancies are even kept fixed during ionic relaxations or molecular dynamics simulations. However, keeping the orbital occupancies fixed, requires that the orbital order does not change during the self-consistency cycle or during the optimization of the orbitals. Imagine, for instance, that the eigenenergy of the 65th orbital moves below the orbital energy of the 64th orbital. Then the subspace diagonalization step will swap both orbitals, but the occupancies will remain as read from the INCAR file (this means that the originally unoccupied 65th orbital will move to the 64th place and it will hence become occupied). This problem can be often circumvented by specifying LDIAG=.FALSE. in the INCAR file.
Note that the partial occupancies are also written to the OUTCAR file, but in this case they are multiplied by 2, i.e. they are between 0 and 2.
In the case of spin-polarized calculations (ISPIN=2), FERWE sets the occupancies of the states in the up-spin channel. Specify the occupancies of the states in the down-spin channel by means of the FERDO tag.
| Mind: If the calculation stops with an error message when reading FERWE, then this may be due to an automatic increase of the number of bands NBANDS in parallel calculation (the new value of NBANDS is indicated in the corresponding warning message). If this is the case, then the number of occupancies provided to FERWE should be increased according to the new NBANDS. |