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KERNEL_TRUNCATION/LTRUNCATE

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Revision as of 10:57, 17 March 2026 by Huebsch (talk | contribs)

KERNEL_TRUNCATION/LTRUNCATE = .True. | .False.
Default: KERNEL_TRUNCATION/LTRUNCATE = .False. 

Description: Truncates the Coulomb kernel to remove electrostatic interactions along non-periodic dimensions.


Setting KERNEL_TRUNCATION/LTRUNCATE = T switches on the Coulomb-kernel-truncation method[1][2][3]. It effectively removes interactions with periodic replicas in non-periodic directions. In other words, the interactions are removed along the surface normal for 2D materials, and along all directions for 0D systems, i.e. for isolated atoms and molecules.

In the simplest implementation of the Coulomb-kernel-truncation method (KERNEL_TRUNCATION/LCOARSEN = F), the computational cell provided in the POSCAR file is internally padded by an additional vacuum (see KERNEL_TRUNCATION/IPAD). This implies increasing the FFT-grid sizes by a certain factor and thus leads to a significant increase in computational cost.

Detailed information about the setting are documented on respective related tags.

Related tags and articles

KERNEL_TRUNCATION/LCOARSEN, KERNEL_TRUNCATION/IDIMENSIONALITY, KERNEL_TRUNCATION/ISURFACE, KERNEL_TRUNCATION/FACTOR, KERNEL_TRUNCATION/IPAD

References