POTCAR: Difference between revisions
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The POTCAR file | The {{FILE|POTCAR}} file contains the pseudopotential for each atomic species used in the calculation. If the number of species is larger than one simply concats the {{FILE|POTCAR}} files of the species. On a UNIX machine you might type the line | ||
cat ~/pot/Al/POTCAR ~/pot/C/POTCAR ~/pot/H/POTCAR >POTCAR | |||
to concat three {{FILE|POTCAR}} files. The first file will correspond to the first species on the {{FILE|POSCAR}} and {{FILE|INCAR}} file and so on. Starting from version VASP 3.2, the {{FILE|POTCAR}} file also contains information about the atoms (i.e. there mass, their valence, the energy of the reference configuration for which the pseudopotential was created etc.). With these new {{FILE|POTCAR}} file it is not necessary to specify valence and mass in the {{FILE|INCAR}} file. If tags for the mass and valence exist in the {{FILE|INCAR}} file they are checked against the parameters found on the {{FILE|POTCAR}} file and error messages are printed. | |||
Mind: Be very careful with the concatenation of the {{FILE|POTCAR}} files, it is a frequent error to give the wrong ordering in the {{FILE|POTCAR}} file! | |||
The new {{FILE|POTCAR}} files also contains a default energy cutoff ({{TAG|ENMAX}} and {{TAG|ENMIN}} line), therefore it is no longer necessary to specify ENCUT in the INCAR file. Of course the value in the {{FILE|INCAR}} file overwrites the default in the {{FILE|POTCAR}} file. For {{FILE|POTCAR}} files with more than one species the maximum cutoffs ({{TAG|ENMAX}} or {{TAG|ENMIN}}) are used for the calculation. For more information about the supplied pseudopotentials please refer to [[Pseudopotentials supplied with VASP|Pseudopotentials]]. | |||
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Revision as of 12:09, 6 June 2012
The POTCAR file contains the pseudopotential for each atomic species used in the calculation. If the number of species is larger than one simply concats the POTCAR files of the species. On a UNIX machine you might type the line
cat ~/pot/Al/POTCAR ~/pot/C/POTCAR ~/pot/H/POTCAR >POTCAR
to concat three POTCAR files. The first file will correspond to the first species on the POSCAR and INCAR file and so on. Starting from version VASP 3.2, the POTCAR file also contains information about the atoms (i.e. there mass, their valence, the energy of the reference configuration for which the pseudopotential was created etc.). With these new POTCAR file it is not necessary to specify valence and mass in the INCAR file. If tags for the mass and valence exist in the INCAR file they are checked against the parameters found on the POTCAR file and error messages are printed. Mind: Be very careful with the concatenation of the POTCAR files, it is a frequent error to give the wrong ordering in the POTCAR file!
The new POTCAR files also contains a default energy cutoff (ENMAX and ENMIN line), therefore it is no longer necessary to specify ENCUT in the INCAR file. Of course the value in the INCAR file overwrites the default in the POTCAR file. For POTCAR files with more than one species the maximum cutoffs (ENMAX or ENMIN) are used for the calculation. For more information about the supplied pseudopotentials please refer to Pseudopotentials.