NGXF

NGXF = [integer]
Default: NGXF = set in accordance with PREC, NGX, ENCUT and ENAUG 

Description: NGXF sets the number of grid points in the "fine" FFT grid along the first lattice vector.

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On this "fine" FFT mesh the localized augmentation charges are represented if ultrasoft pseudopotentials (USPPs) or the PAW method are used. In case USPPs are used, the local potentials (exchange-correlation, Hartree-potential and ionic potentials) are also calculated on this "fine" FFT-mesh.

By default NGXF is set in accordance with the requested "precision"-mode (PREC), NGX, and the plane wave kinetic energy cutoffs ENCUT and ENAUG:

PREC	NGX	NGXF
Normal	3/2×Gcut	2×NGX
Single	3/2×Gcut	NGX
Accurate	2×Gcut	2×NGX
Low	3/2×Gcut	3×Gaug
Medium	3/2×Gcut	4×Gaug
High	2×Gcut	16/3×Gaug

where

$E_{\rm cut}=\frac{\hbar^2}{2m_e}G_{\rm cut}^2 \qquad E_{\rm aug}=\frac{\hbar^2}{2m_e}G_{\rm aug}^2$

with E_cut=ENCUT and E_aug=ENAUG.

Alternatively NGXF may be set to a specific value in the INCAR file.

Related tags and articles

NGX, NGY, NGZ, NGYF, NGZF, PREC, ENCUT, ENAUG, ENMAX

Examples that use this tag

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