PHON G CUTOFF: Difference between revisions

Revision as of 09:40, 20 July 2022

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.

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.

@@ Line 3: / Line 3: @@
 {{DEF|PHON_G_CUTOFF|None|}}
-Description: {{TAG|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the number of G-vectors involved in the Ewald sum in polar phonon calculations.
+Description: {{TAG|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the number of <math>\mathbf{G}</math> vectors involved in the Ewald sum in polar phonon calculations.
 ----
-If the material is polar (i.e. has more than one different atom type) a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion.
+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 {{TAG|LPHON_POLAR}}=.TRUE. and supplying the static dielectric tensor ({{TAG|PHON_DIELECTRIC}}) and the Born-effective charges ({{TAG|PHON_BORN_CHARGES}}) which can be obtained on a separate VASP run using the {{TAG|LEPSILON}} or {{TAG|LCALCEPS}} tag. The long-range part is evaluated using an Ewald sum with the number of G-vectors in reciprocal space being determined using a cutoff length ({{TAG|PHON_G_CUTOFF}}).
+This is activated by setting {{TAG|LPHON_POLAR}}=.TRUE. and supplying the static dielectric tensor ({{TAG|PHON_DIELECTRIC}}) and the Born-effective charges ({{TAG|PHON_BORN_CHARGES}}) which can be obtained in a separate VASP calculation using the {{TAG|LEPSILON}} or {{TAG|LCALCEPS}} tag. The long-range part is evaluated using an Ewald sum with the number of <math>\mathbf{G}</math> vectors in reciprocal space being determined using a cutoff length ({{TAG|PHON_G_CUTOFF}}).
 {{NB|mind| Only available as of VASP 6.3.2.}}

Revision as of 09:40, 20 July 2022

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