PARCHG: Difference between revisions

Revision as of 12:01, 9 February 2024

PARCHG is an output file created when partial charge densities are calculated by setting LPARD = .TRUE.. The file has the same structure as the CHG file, containing the structure followed by the charge density on the fine FFT grid, but missing the augmentation occupancies that are written to CHGCAR. The units are also equivalent to CHG and CHGCAR.

The density written to PARCHG is the valence electron density that was converged selfconsistently in a previous run. The bands and k points that contribute to the partial charges are selected by the IBAND, NBMOD, EINT and KPUSE tags, allowing for fine control of the contributions to the partial charge density.

Spin-polarized calculation

In spin-polarized calculations, two data sets are stored in the PARCHG file. The first set contains the total partial density (spin up + spin down) and the second one is the magnetization density (spin up - spin down). Each block is separated by a blank line and a line containing the fine FFT grid dimensions NGXF NGYF NGZF.

structure
total charge density (spin up + spin down)
magnetization density (spin up - spin down)

Variants of PARCHG with bands or k points separated

If LSEPB and/or LSEPK are set to .TRUE. variants of the PARCHG file are written, separating the contributing bands and k points respectively. The units and format of the files stay the same.

If LSEPB = .TRUE. but LSEPK = .FALSE. PARCHG.nb.ALLK files will be written, with nb an index running through all bands contributing to the partial charge density.

LSEPB = .FALSE. but LSEPK = .TRUE. results in PARCHG.ALLB.nk files being created, with nk running over all k points in KPUSE or all k points if KPUSE is not set.

For both LSEPB = .TRUE. and LSEPK = .TRUE. all combinations are written to PARCHG.nb.nk files.

@@ Line 1: / Line 1: @@
 {{FILE|PARCHG}} is an output file created when partial charge densities are calculated by setting {{TAG|LPARD}} = .TRUE..
-The file has the same structure as the {{FILE|CHG}} file, containing the structure followed by the charge density on the fine FFT grid, but missing the augmentation occupancies that are written to {{FILE|CHGCAR}}. The units are also equivalent to {{FILE|CHG}} and {{FILE|CHGCAR}}, charge density <math>n(r)</math> multiplied by the grid volume <math>V_\mathrm{grid}</math> = {{TAG|NGXF}}<math>\times</math>{{TAG|NGYF}}<math>\times</math>{{TAG|NGZF}}, <math>n(r)\times V_{\mathrm{grid}}</math>.
+The file has the same structure as the {{FILE|CHG}} file, containing the structure followed by the charge density on the fine FFT grid, but missing the augmentation occupancies that are written to {{FILE|CHGCAR}}. The units are also equivalent to {{FILE|CHG}} and {{FILE|CHGCAR}}.
-The density written to {{FILE|PARCHG}} is the valence electron density, that was converged selfconsistently in a previous run.
+The density written to {{FILE|PARCHG}} is the valence electron density that was converged selfconsistently in a previous run.
 The bands and '''k''' points that contribute to the partial charges are selected by the {{TAG|IBAND}}, {{TAG|NBMOD}}, {{TAG|EINT}} and {{TAG|KPUSE}} tags, allowing for fine control of the contributions to the partial charge density.
 === Spin-polarized calculation===
-In spin-polarized calculations, two sets of data are stored in the {{FILE|PARCHG}} file.
+In spin-polarized calculations, two data sets are stored in the {{FILE|PARCHG}} file.
 The first set contains the total partial density (spin up + spin down) and the second one is the magnetization density (spin up - spin down). Each block is separated by a blank line and a line containing the fine FFT grid dimensions {{TAG|NGXF}} {{TAG|NGYF}} {{TAG|NGZF}}.
 * structure

Revision as of 12:01, 9 February 2024

Spin-polarized calculation

Variants of PARCHG with bands or k points separated

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