KSPACING: Difference between revisions
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{{TAG|KSPACING}} is the smallest allowed spacing between k | {{TAG|KSPACING}} is the smallest allowed spacing between k points in units of | ||
<math>\AA^{-1}</math>. The number of k-points increases when the spacing is decreased. | <math>\AA^{-1}</math>. The number of k-points increases when the spacing is decreased. | ||
The number of k-points in the direction of the first, second and third | The number of k-points in the direction of the first, second and third | ||
reciprocal lattice vector is determined by | reciprocal lattice vector is determined by | ||
<math> \mathrm{max}(1, | \vec{b}(i)| / \mathrm{KSPACING} ). </math> | <math> \mathrm{max}(1, | \vec{b}(i)| / \mathrm{KSPACING} ). </math> | ||
Revision as of 08:55, 28 April 2017
KSPACING = [real]
Default: KSPACING = 0.5
Description: The tag KSPACING determines the number of k-points if the KPOINTS file is not present.
KSPACING is the smallest allowed spacing between k points in units of [math]\displaystyle{ \AA^{-1} }[/math]. The number of k-points increases when the spacing is decreased. The number of k-points in the direction of the first, second and third reciprocal lattice vector is determined by
[math]\displaystyle{ \mathrm{max}(1, | \vec{b}(i)| / \mathrm{KSPACING} ). }[/math]
These values are rounded to the next integer. The generated grid is either centred at the [math]\displaystyle{ \Gamma }[/math] point (e.g. includes the [math]\displaystyle{ \Gamma }[/math] point) (KGAMMA=.TRUE.) or is shifted away from the [math]\displaystyle{ \Gamma }[/math] point, as usually done for Monkhorst Pack grids (KGAMMA=.FALSE.). Per default, the grids include the [math]\displaystyle{ \Gamma }[/math] point.