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# ENCUT

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ENCUT = [real]

 Default: ENCUT = largest ENMAX from the POTCAR-file

Description: EMAX specifies the Cut-off energy for plane wave basis set in eV.

All plane-waves with a kinetic energy smaller than ${\displaystyle E_{\mathrm {cut} }}$ are included in the basis set: i.e.

${\displaystyle |{\mathbf {G}}+{\mathbf {k}}|}$ with ${\displaystyle E_{{{\mathrm {cut}}}}={\frac {\hbar ^{2}}{2m}}G_{{{\mathrm {cut}}}}^{2}}$

The number of plane waves differs for each k-point, leading to a superior beahviour for e.g. energy-volume calculations. If the volume is increased the total number of plane waves changes fairly smoothly. The criterion ${\displaystyle |{\mathbf {G} }| (i.e. same basis set for each ${\displaystyle {\mathbf {k}}}$-point) would lead to a very rough energy-volume curve and, generally, slower energy convergence.

Starting from version VASP 3.2 the POTCAR files contains a default ENMAX (and ENMIN) line, therefore it is in principle not necessary to specify ENCUT in the INCAR file. For calculations with more than one species, the maximum cutoff ENMAX or ENMIN value is used for the calculation (see PREC). For consistency reasons we still recommend to specify the cutoff manually in the INCAR file and keep in constant throughout a set of calculations.