PHON_G_CUTOFF

PHON_G_CUTOFF = [3x3xNIONS real] 

Default: PHON_G_CUTOFF

= None

Description: PHON_G_CUTOFF sets the cutoff radius in reciprocal space used to determine the number of $\mathbf{G}$ vectors involved in the Ewald sum in polar phonon calculations.

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If the material is polar (i.e. has more than one atom type), a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion. This is activated by setting LPHON_POLAR=.TRUE. and supplying the static dielectric tensor (PHON_DIELECTRIC) and the Born-effective charges (PHON_BORN_CHARGES) which can be obtained in a separate VASP calculation using the LEPSILON or LCALCEPS tag. The long-range part is evaluated using an Ewald sum with the number of $\mathbf{G}$ vectors in reciprocal space being determined using a cutoff length (PHON_G_CUTOFF).

Mind: Only available as of VASP 6.3.2.

Related tags and articles

QPOINTS, LPHON_DISPERSION, PHON_NWRITE, LPHON_POLAR, PHON_DIELECTRIC, PHON_BORN_CHARGES

Examples that use this tag