WRT_POTENTIAL

From VASP Wiki
Revision as of 09:46, 7 February 2024 by Huebsch (talk | contribs)

WRT_POTENTIAL = string
Default: WRT_POTENTIAL = None 

Description: Select which component of the local potential to be written as a post-processing step.

WRT_POTENTIAL can select one or multiple local potentials on the real-space grid in the unit cell to be written, e.g., 

 WRT_POTENTIAL = total

or 

 WRT_POTENTIAL = hartree ionic

The output is written to vaspout.h5 and can be accessed either by py4vasp or HDF5 command-line tools (h5ls, h5dump). 

 import py4vasp as pv
 calc = pv.Calculation.from_path(".")
 pot_dict = calc.potential.read("total")

The above allows the creation of a Python dictionary with the potential data. 

 h5ls -r vaspout.h5

The above shows the table of contents of vaspout.h5. Depending on the keywords specified with WRT_POTENTIAL and the system it yields 

 /results/potential       Group
 /results/potential/grid  Dataset {3}
 /results/potential/hartree Dataset {1, 24, 24, 24}
 /results/potential/ionic Dataset {1, 24, 24, 24}
 /results/potential/total Dataset {4, 24, 24, 24}
 /results/potential/xc    Dataset {4, 24, 24, 24}

The grid density can be increased by choosing a higher value for ENCUT or explicitly by NGX, NGY, NGZ.

The first dimension of the datasets in /results/potential is 1 for nonmagnetic calculation, 2 for spin-polarized calculation, and 4 for noncollinear calculations. In case the potential is scalar, i.e., has no B-field-like contribution that couples to the magnetization, only the 1st component exists. Hence, for hartree and ionic, the first dimension is 1. The components for the magnetic calculations correspond to the spinor representation with the scalar potential in the first component and the B-field in the second (ISPIN=2) or Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle B_1} , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle B_2} and Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle B_3} in the 2nd, 3rd and 4th component (LNONCOLLINEAR=T) in the basis of Pauli matrices Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle \{\sigma _{1}} , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle \sigma _{2}} , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle \mathbf{\sigma}_3\}} given by SAXIS.

Mind: As a convention, the Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle \mathbf{G}{{=}}0} component in reciprocal-space representations of both, the Hartree and ionic, potentials are set to zero. This implies that considering the sum of the Hartree and ionic potentials is more meaningful than either potential individually.

WRT_POTENTIAL can be run as a post-processing step by restarting from a converged CHGCAR and setting ALGO=None. It is available for VASP >= 6.4.3.

Options to select

total

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle V_{\text{total}}(\mathbf{r}) + B_{\text{total}}(\mathbf{r}) = V_{\text{ion}}(\mathbf{r}) + V_{\text{hartree}}(\mathbf{r})+ V_{\text{xc}}(\mathbf{r}) + B_{\text{xc}}(\mathbf{r}) }
The output is written to /results/potential/total, as well as LOCPOT.

hartree

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle V_{\text{hartree}}(\mathbf{r}) = \int \frac{n(\mathbf{r'})}{|\mathbf{r}-\mathbf{r'}|}d\mathbf{r'} }
The output is written to /results/potential/hartree.

ionic

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle V_{\text{ion}}(\mathbf{r})} as mimicked by the pseudopotentials of the PAW method. The output is written to /results/potential/ionic.

xc

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): {\displaystyle V_{\text{xc}}(\mathbf{r}) + B_{\text{xc}}(\mathbf{r}) } as defined by the selected exchange-correlation functional. The output is written to /results/potential/xc.
Mind: This only corresponds to the (semi-)local functionals, i.e., LDA, GGA, non-local vdW-DF functionals, and does not account for either the potential Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://www.vasp.at/wiki/restbase/vasp.at/v1/":): \mu associated with the kinetic energy density in METAGGA or the nonlocal Fock exchange considered in hybrid functionals.

Related tags and articles

LVACPOTAV, LVTOT, LVHAR, WRT_POTENTIAL, LDIPOL, ENCUT, NGX, NGY, NGZ

Retrieved from "https://www.vasp.at/wiki/index.php?title=WRT_POTENTIAL&oldid=23551"