KPOINTS OPT: Difference between revisions

Latest revision as of 14:29, 22 July 2024

KPOINTS_OPT is an optional input file to perform an additional one-shot calculation after self-consistency is reached. The format is the same as for the KPOINTS file. VASP first performs a self-consistent calculation using the k points specified in the KPOINTS file and then performs an additional one-shot calculation to obtain the Kohn–Sham orbitals and eigenenergies at the k points specified in the KPOINTS_OPT file.

Important:

The KPOINTS file must contain a uniform k mesh, when the KPOINTS_OPT file should be used afterward.
In the case of a functional using the long-range Hartree-Fock exchange (e.g., unscreened hybrid functionals), the default method for treating the Coulomb singularity (HFRCUT=0) is not adapted to do so for states at k-points that have not been included in the calculation of the Fock potential. Instead, HFRCUT=-1 should be used.

KPOINTS_OPT is read automatically when present. To avoid this, set LKPOINTS_OPT=.FALSE. in the INCAR file. VASP writes the PROCAR_OPT file when LORBIT>10 and corresponding fields in the vaspout.h5 file indicated by the keyword kpoints_opt.

Mind: Available as of VASP 6.3.0.

Related tags and sections

LKPOINTS_OPT, KPOINTS, KSPACING, PROCAR_OPT, KPOINTS_OPT_NKBATCH

@@ Line 1: / Line 1: @@
-{{FILE|KPOINTS_OPT}} is an optional input file to perform an additional one-shot calculation after convergence. It has the same format as the {{FILE|KPOINTS}} file and is read automatically when present. VASP first performs a self-consistent calculation using the '''k''' points specified in the {{FILE|KPOINTS}} file and then performs an additional one-shot calculation to obtain the Kohn&ndash;Sham (KS) orbitals at the '''k''' points specified in the {{FILE|KPOINTS_OPT}} file.
+{{DISPLAYTITLE:KPOINTS_OPT}}
-{{NB|important| The {{FILE|KPOINTS}} file must contain a uniform '''k''' mesh, when the {{FILE|KPOINTS_OPT}} file should be used afterward.}}
+{{FILE|KPOINTS_OPT}} is an optional input file to perform an additional one-shot calculation after self-consistency is reached. The format is the same as for the {{FILE|KPOINTS}} file. VASP first performs a self-consistent calculation using the '''k''' points specified in the {{FILE|KPOINTS}} file and then performs an additional one-shot calculation to obtain the Kohn&ndash;Sham orbitals and eigenenergies at the '''k''' points specified in the {{FILE|KPOINTS_OPT}} file.
-This functionality is convenient for the following use cases among others:
+{{NB|important|
+*The {{FILE|KPOINTS}} file must contain a uniform '''k''' mesh, when the {{FILE|KPOINTS_OPT}} file should be used afterward.
-* compute the band structure in one go,
+*In the case of a functional using the long-range Hartree-Fock exchange (e.g., unscreened hybrid functionals), the default method for treating the Coulomb singularity ({{TAG|HFRCUT}}{{=}}0) is not adapted to do so for states at k-points that have not been included in the calculation of the Fock potential. Instead, {{TAG|HFRCUT}}{{=}}-1 should be used.}}
-* compute optical properties on a denser '''k''' mesh,
+{{FILE|KPOINTS_OPT}} is read automatically when present. To avoid this, set {{TAG|LKPOINTS_OPT}}<code>=.FALSE.</code> in the {{FILE|INCAR}} file.
-* compute the KS orbitals in a specific region of the BZ, e.g., to investigate a band crossing more closely.
+VASP writes the {{FILE|PROCAR_OPT}} file when {{TAG|LORBIT}}>10 and corresponding fields in the {{FILE|vaspout.h5}} file indicated by the keyword ''kpoints_opt''.
-The use of the {{FILE|KPOINTS_OPT}} file can be avoided by setting the {{TAG|LKPOINTS_OPT}} tag to <code>.FALSE.</code> in the {{FILE|INCAR}} file.
-VASP writes the {{FILE|PROCAR_OPT}} file and corresponding fields in the {{FILE|vaspout.h5}} file indicated by the keyword ''kpoints_opt''.
 {{NB|mind| Available as of VASP 6.3.0.}}
 == Related tags and sections ==
-{{FILE|KPOINTS}}, {{TAG|KSPACING}}
+{{TAG|LKPOINTS_OPT}}, {{FILE|KPOINTS}}, {{TAG|KSPACING}}, {{FILE|PROCAR_OPT}}, {{TAG|KPOINTS_OPT_NKBATCH}}
-[[Category:VASP]][[Category:Files]][[Category:Input Files]]
+[[Category:VASP]][[Category:Files]][[Category:Input files]][[Category:Band structure]]