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Input

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Overview > Input > Preparing a Super Cell >Output > List of tutorials

VASP basically needs 4 input files for standard production runs:

INCAR

The INCAR file holds the input parameters which "steer" the calculation.

  • The default values set by VASP itself are a clever choice to do standard calculations.
  • These standard settings can be modified to specify:
    • What do you want to do? (scf calculation, DOS, dielectric properties ...)
    • You can give parameters to fulfill your requirements concerning required precision, requested convergence, calculation time ...


POSCAR

The POSCAR file contains the information on the structure.

  • A simple POSCAR file may look like this:
fcc:  Ni
3.53
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
Ni
1
Selective Dyn
Cartesian
0 0 0  T T T
  • The description of each line is given as follows:
    • 1: Header (comment).
    • 2: Overall scaling constant.
    • 3-6: Bravais matrix.
    • 4: Name(s) of the atom(s).
    • 5: Number of the atoms (of each atom type).
    • 6: (optional: selective dynamics).
    • 7: Specifies which coordinate system is used ("cartesian" or "direct").
    • 8-x: Positions of the atoms.


KPOINTS

The KPOINTS file determines the sampling of the 1st Brillouin zone.

Automatic mesh
0
G (M)
4 4 4
0.  0.  0.
  • The description of each line is given as follows:
    • 1: Header (comment).
    • 2: Specifies the k mesh generation type. : automatic generation scheme.
    • 3: -centered (Monkhorst-Pack) grid.
    • 4: Number of subdivisions in each direction.
    • 5: Optional shift of the mesh.


POTCAR

The POTCAR file contains the relevant information concerning the pseudo potentials that are necessary to run the calculation:

  • Data that was required for generating the pseudo potentials.
  • Number of valence electrons.
  • Atomic mass.
  • Energy cut-off.

If the cell contains different atomic species, the corresponding POTCAR files have to be concatenated, in the same order as the atomic species are given in the POSCAR file.

N.B.: Different XC-types must not be mixed.

Overview > Input > Preparing a Super Cell >Output > List of tutorials

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