KERNEL TRUNCATION/IDIMENSIONALITY

KERNEL_TRUNCATION/IDIMENSIONALITY = 0 | 2 | 3
Default: KERNEL_TRUNCATION/IDIMENSIONALITY = 3 

Description: KERNEL_TRUNCATION/IDIMENSIONALITY specifies the boundary condition used to compute the hartree and ionic potential.

Mind: IF KERNEL_TRUNCATION/LTRUNCATE is switched off, all other KERNEL_TRUNCATION tags, i.e. KERNEL_TRUNCATION/IDIMENSIONALITY, KERNEL_TRUNCATION/LCOARSEN, and KERNEL_TRUNCATION/ISURFACE will be ignored.

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If KERNEL_TRUNCATION/LTRUNCATE = T, KERNEL_TRUNCATION/IDIMENSIONALITY determines the boundary condition that is used to compute the local potential. The default value of 3 implies that the system is periodic in all dimensions, i.e. there is no influence of kernel truncation on the resulting energies and forces. Setting KERNEL_TRUNCATION/IDIMENSIONALITY to either 0 or 2 uses the 0D and 2D truncated kernel respectively. These kernels create 0D (i.e. no periodic interactions, as is the case of molecules) and 2D (i.e. periodic interactions only in two dimensions, as in the case for surfaces).

KERNEL_TRUNCATION/IDIMENSIONALITY = 0

Consider using the option when computing energies and forces of atoms and molecules. Recommended INCAR tags to be used with option are

 KERNEL_TRUNCATION {
       LTRUNCATE      = T
       IDIMENIONALITY = 0
       LCOARSEN       = T
 }

KERNEL_TRUNCATION/IDIMENSIONALITY = 2

Use this option when computing the energies and forces of 2D and quasi-2D systems, such as 2D materials and surfaces. We suggest setting the following INCAR tags for a surface that is oriented along the z-axis

 KERNEL_TRUNCATION {
       LTRUNCATE      = T
       IDIMENIONALITY = 2
       LCOARSEN       = T
       ISURFACE       = 3
 }

Related tags and articles

KERNEL_TRUNCATION/LTRUNCATE, KERNEL_TRUNCATION/LCOARSEN, KERNEL_TRUNCATION/ISURFACE