POT: Difference between revisions

Latest revision as of 11:40, 22 June 2026

The POT file contains the total local potential (in eV), including the PAW augmentation part. It is written for optimized-effective-potential (OEP)-type calculations — such as the local Hartree-Fock and EXX-OEP methods, when LVTOT = True, and it stores the local potential as the restart quantity for such calculations.

As of VASP 6.6.0, LVTOT = True together with LH5 = True writes the content of the POT file to the restart file vaspwave.h5 instead. When restarting, a legacy POT file is used in preference to vaspwave.h5 if both are present.

Tip: If you are interested in the local potential as a quantity (and not in restarting a calculation), use the LOCPOT file and/or the WRT_POTENTIAL tag instead.

Format

The POT file uses the same block format as the CHGCAR file, with the potential (in eV) in place of the charge density. Each block consists of:

Structure in POSCAR format
FFT-grid dimensions NGXF, NGYF, NGZF
The local potential on the FFT grid, written with multiple real numbers per line (data runs fastest over NX, slowest over NZ, as for CHGCAR)
The PAW augmentation part

Unlike CHGCAR, which stores the charge density and magnetization, the potential is written in the following spin representation:

Non-spin-polarized calculations: a single block with the total local potential.
Collinear spin-polarized calculations (ISPIN = 2): two blocks, the spin-up and spin-down potentials.
Noncollinear calculations (LNONCOLLINEAR = True): the (density, magnetization) representation, i.e., the scalar potential and the three components of the magnetic field, in the spinor basis set by SAXIS.

Each potential block is followed by its corresponding PAW augmentation part.

Warning: The augmentation occupancies are written up to the l-quantum number set by LMAXMIX. See LMAXMIX for the consequences of restarting without the appropriate one-center occupancies.

@@ Line 1: / Line 1: @@
-The {{FILE|POT}} file contains the local potential (in eV), including the augmentation part. It is written if {{TAG|LVTOT}}=T, and it can be used to restart a calculation that requires the local potential as a restart quantity, e.g., for the optimized effective potential (OEP) method.
+The {{FILE|POT}} file contains the total local potential (in eV), including the PAW augmentation part. It is written for optimized-effective-potential (OEP)-type calculations — such as the local Hartree-Fock and EXX-OEP methods, when {{TAG|LVTOT|True}}, and it stores the local potential as the restart quantity for such calculations.
-For {{TAG|LVTOT}}=T and {{TAG|LH5}}=T, the content of the {{FILE|POT}} file is written to the restart file {{FILE|vaspwave.h5}} instead.
+As of VASP 6.6.0, {{TAG|LVTOT|True}} together with {{TAG|LH5|True}} writes the content of the {{FILE|POT}} file to the restart file {{FILE|vaspwave.h5}} instead. When restarting, a legacy {{FILE|POT}} file is used in preference to {{FILE|vaspwave.h5}} if both are present.
+{{NB|tip|If you are interested in the local potential as a quantity (and not in restarting a calculation), use the {{FILE|LOCPOT}} file and/or the {{TAG|WRT_POTENTIAL}} tag instead.}}
-If you are interested in the local potential as a quantity (and not interested in restarting a calculation), we recommend the {{FILE|LOCPOT}} file and/or setting {{TAG|WRT_POTENTIAL}}.
+== Format ==
+The {{FILE|POT}} file uses the same block format as the {{FILE|CHGCAR}} file, with the potential (in eV) in place of the charge density. Each block consists of:
+* Structure in {{FILE|POSCAR}} format
+* FFT-grid dimensions {{TAG|NGXF}}, {{TAG|NGYF}}, {{TAG|NGZF}}
+* The local potential on the FFT grid, written with multiple real numbers per line (data runs fastest over NX, slowest over NZ, as for {{FILE|CHGCAR}})
+* The PAW augmentation part
-The format is similar to that of the {{TAG|LOCPOT}} file but it additionally contains the augmentation part at the end of each block.
+Unlike {{FILE|CHGCAR}}, which stores the charge density and magnetization, the potential is written in the following spin representation:
+* Non-spin-polarized calculations: a single block with the total local potential.
+* Collinear spin-polarized calculations ({{TAG|ISPIN|2}}): two blocks, the spin-up and spin-down potentials.
+* Noncollinear calculations ({{TAG|LNONCOLLINEAR|True}}): the (density, magnetization) representation, i.e., the scalar potential and the three components of the magnetic field, in the spinor basis set by {{TAG|SAXIS}}.
+Each potential block is followed by its corresponding PAW augmentation part.
+{{NB|warning|The augmentation occupancies are written up to the ''l''-quantum number set by {{TAG|LMAXMIX}}. See {{TAG|LMAXMIX}} for the consequences of restarting without the appropriate one-center occupancies.}}
 == Related tags and articles ==
+[[Restart and output files cheat sheet]]
+{{FILE|CHGCAR}},
 {{FILE|LOCPOT}},
+{{FILE|vaspwave.h5}},
 {{TAG|LVTOT}},
 {{TAG|LVHAR}},
-{{TAG|WRT_POTENTIAL}}
+{{TAG|WRT_POTENTIAL}},
+{{TAG|LH5}},
+{{TAG|LMAXMIX}}
 [[Category:Files]][[Category:Output files]][[Category:Potential]]