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Band decomposed chargedensity ( parameters)
VASP.4.4 can calculate the partial (band decomposed)
charge density according to parameters specified in the file INCAR.
Mind that the partial charge density can be calculated only
if a preconverged WAVECAR file exists, VASP enters the
evaluation routine very quickly and stops immediately after
evaluating the partial charge density. This implementation
was chosen to allow a fast (almost interactive) recalculation
of the charge density for particular bands and kpoints.
The following parameters control the behavior of VASP.
- LPARD: Evaluate partial (band and/or k-point) decomposed charge density.
We want to stress again, that the wavefunctions read
from WAVECAR must be converged in a separate prior run.
If only LPARD is set (and none of the tags discussed below),
the total charge density is evaluated from the wavefunctions and
written to CHGCAR.
- There are several ways how to specify
for which bands the charge density is evaluated: In general the
input lines with IBAND, EINT and NBMOD control this respect of
the routine:
- IBAND: Calculate the partial charge density for all bands specified in
the array IBAND. If IBAND is specified in the INCAR file and
NBMOD is not given,
NBMOD is set automatically to the size of the array. If IBAND is
for instance
IBAND= 20 21 22 23
the charge density will be calculated for bands 20 to 23.
- EINT: Specifies the energy range of the bands that
are used for the evaluation of the partial charge density.
Two real values should
be given, if only one value is specified, the second one
is set to
. If EINT is given and NBMOD is not specified,
NBMOD is set automatically to -2.
- NBMOD: This integer variable can take the following values

- Number of values in the array IBAND.
If IBAND is specified, NBMOD is
set automatically to the correct value
(in that case NBMOD should not be set manually in the INCAR file)
- 0
- Take all bands to calculate the charge density, even
unoccupied bands are taken into account.
- -1
- Calculate the total charge density as usual. This is the default
value if nothing else is given.
- -2
- Calculate the partial charge density for electrons with there
eigenvalues in the range specified by EINT.
- -3
- The same as before, but the energy range is given vs. the Fermi
energy.
- KPUSE:
KPUSE specifies which k-points are used in
the evaluation of the partial dos. KPUSE is an array of
integer values.
KPUSE= 1 2 3 4
means that the charge density is evaluated and summed for
the first four k-points. Be careful: VASP
changes the kpoint weights if KPUSE is specified.
- LSEPB: Specifies whether the charge density is calculated for
every band separately and written
to a file PARCHG.nb.
(TRUE) or whether charge density
is merged for all selected bands and write to the file
PARCHG.ALLB.
or PARCHG. Default is FALSE.
- LSEPK: Specifies whether the charge density of every
k-point is write to
the files PARCHG.
.nk (TRUE) or whether it is merged (FALSE)
to a single file.
If the merged file is written, then the weight of each k-point
is determined from the KPOINTS file, otherwise the
kpoints weights of one are chosen.
Next: Berry phase calculations
Up: The INCAR File
Previous: Dipole corrections for defects
  Contents
Georg Kresse
2007-03-01