LOCPOT

The LOCPOT file stores the local potential [math]\displaystyle{ V_{\text{LOCPOT}}(\mathbf{r}) }[/math] (in eV) given by:

[math]\displaystyle{ V_{\text{LOCPOT}}(\mathbf{r}) = V(\mathbf{r}) + \int \frac{n(\mathbf{r'})}{|\mathbf{r}-\mathbf{r'}|}d\mathbf{r'}+ V_{\text{XC}}(\mathbf{r}) }[/math]

where [math]\displaystyle{ V(\mathbf{r}) }[/math] is the ionic potential, the second term is the Hartree potential and [math]\displaystyle{ V_{\text{XC}}(\mathbf{r}) }[/math] is the exchange-correlation potential.

To write this file, LVTOT=.TRUE. or LVHAR=.TRUE. must be set in the INCAR file. If LVHAR=.TRUE. the [math]\displaystyle{ V_{\text{XC}}(\mathbf{r}) }[/math] is not included in [math]\displaystyle{ V_{\text{LOCPOT}}(\mathbf{r}) }[/math].

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.

Note for versions older than vasp.5.1.12: please check whether your version supports this tag (it is written out at the beginning of the OUTCAR file). Versions not supporting LVHAR might or not add [math]\displaystyle{ V_{\text{XC}}(\mathbf{r}) }[/math]. Please check this by searching for LEXCHG=-1 in main.F. If the line LEXCHG=-1 is commented out [math]\displaystyle{ V_{\text{XC}}(\mathbf{r}) }[/math] is added otherwise it is not.

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