LOCPOT: Difference between revisions

Revision as of 20:20, 18 January 2021

The LOCPOT file contains the total local potential (in eV).

To write this file, the line

LVTOT = .TRUE.

must exist in the INCAR file. In the present version, the only electrostatic part of the potential is written (exchange correlation is not added). This is desirable for the evaluation of the work-function, because the electrostatic potential converges more rapidly to the vacuum level than the total potential. However if the exchange correlation potential is to be included, change one line in main.F:

! comment out the following line to add  exchange correlation
!         INFO%LEXCHG=-1
         CALL POTLOK(...)

Mind: Older versions might have had a different behavior, when they were retrieved from the server. Please always check yourself, whether main.F is working in the way you expect (simply search for LEXCHG=-1 in main.F). If the line LEXCHG=-1 is commented out, the exchange correlation is added. It is recommended to avoid wrap around errors, when evaluating LOCPOT. This can be done by specifying PREC=High in the INCAR file.

The LOCPOT file format is similar to that of the CHGCAR file but it does not have the same data arrangement. For spin unpolarized calculations it contains a single dataset with the potential. For collinear spin calculations (ISPIN=2), it contains two datasets: spin up and spin down. For noncollinear calculations (LNONCOLLINEAR=.TRUE.), it contains four datasets with spinor representation of the potential.

For VASP.5.2.12 and newer: LVTOT=.TRUE. writes the local potential including the exchange-correlation contribution on LOCPOT. LVHAR=.TRUE. writes the local potential excluding the exchange-correlation potential on LOCPOT.

@@ Line 12: / Line 12: @@
 Mind:
 Older versions might have had a different behavior, when they were retrieved from the server. Please always check yourself, whether main.F is working in the way you expect (simply search for ''LEXCHG=-1'' in main.F). If the line ''LEXCHG=-1'' is commented out, the exchange correlation is added. It is recommended to avoid wrap around errors, when evaluating {{TAG|LOCPOT}}. This can be done by specifying {{TAG|PREC}}=''High'' in the {{TAG|INCAR}} file.
-The data arrangement on the {{TAG|LOCPOT}} file is similar to that of the {{TAG|CHGCAR}} file.
+The {{TAG|LOCPOT}} file format is similar to that of the {{TAG|CHGCAR}} file but it does not have the same data arrangement.
+For spin unpolarized calculations it contains a single dataset with the potential.
+For collinear spin calculations (ISPIN=2), it contains two datasets: spin up and spin down.
+For noncollinear calculations (LNONCOLLINEAR=.TRUE.), it contains four datasets with spinor representation of the potential.
 For VASP.5.2.12 and newer: {{TAG|LVTOT}}=.TRUE. writes the local potential ''including'' the exchange-correlation contribution on {{TAG|LOCPOT}}. {{TAG|LVHAR}}=.TRUE. writes the local potential ''excluding'' the exchange-correlation potential on {{TAG|LOCPOT}}.