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NGXF

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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.


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 NGX
Single 3/2×Gcut NGX
Accurate 2×Gcut 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 Ecut=ENCUT and Eaug=ENAUG.

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

Related Tags and Sections

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


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