NGXF: Difference between revisions

Revision as of 08:19, 17 October 2023

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× $G_{\rm cut}$	2×NGX
Single (VASP.5)	3/2× $G_{\rm cut}$	NGX
Single (VASP.6)	2× $G_{\rm cut}$	NGX
SingleN (VASP.6)	3/2× $G_{\rm cut}$	NGX
Accurate	2× $G_{\rm cut}$	2×NGX
Low	3/2× $G_{\rm cut}$	3× $G_{\rm aug}$
Medium	3/2× $G_{\rm cut}$	4× $G_{\rm aug}$
High	2× $G_{\rm cut}$	16/3× $G_{\rm aug}$

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 $E_{\rm cut}$ =ENCUT and $E_{\rm aug}$ =ENAUG.

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

@@ Line 28: / Line 28: @@
 where
 :<math>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</math>
-with E<sub>cut</sub>={{TAG|ENCUT}} and E<sub>aug</sub>={{TAG|ENAUG}}.
+with <math>E_{\rm cut}</math>={{TAG|ENCUT}} and <math>E_{\rm aug}</math>={{TAG|ENAUG}}.
-Alternatively {{TAG|NGXF}} may be set to a specific value in the {{FILE|INCAR}} file.
+Alternatively {{TAG|NGXF}} can be set to a specific value in the {{FILE|INCAR}} file.
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