Jump to content

Requests for technical support from the VASP team should be posted in the VASP Forum.

DFT-D4: Difference between revisions

From VASP Wiki
← Older editNewer edit →
VisualWikitext
Ftran (talk | contribs)
6,013 edits
Undo revision 33404 by Ftran (talk)
Tag: Undo
Ftran (talk | contribs)
6,013 edits
Undo revision 33403 by Ftran (talk)
Tag: Undo
Line 1: Line 1:
DFT-D4 is an external package that can be [[Makefile.include#DFT-D4_.28optional.29|linked to VASP]].
DFT-D4 is an external package maintained by the Grimme group that can be [[Makefile.include#DFT-D4_.28optional.29|linked to VASP]].
Read the [https://dftd4.readthedocs.io/en/latest/ documentation] for more information about this package.
Read the [https://dftd4.readthedocs.io/en/latest/ documentation] for more information about this package.
DFT-D4 adds [[:Category:Van der Waals functionals|van-der-Waals (vdW) interactions]] to DFT because they are not included in most exchange-correlation functionals.
DFT-D4 adds [[:Category:Van der Waals functionals|van-der-Waals (vdW) interactions]] to DFT because they are not included in most exchange-correlation functionals.
Line 16: Line 16:
{{NB|warning|Below, we explain how to tweak the parameters of DFT-D4. Typically, you should not modify them unless you have a very good reason, e.g., because the interface is not implemented for the exchange-correlation functional you use.}}
{{NB|warning|Below, we explain how to tweak the parameters of DFT-D4. Typically, you should not modify them unless you have a very good reason, e.g., because the interface is not implemented for the exchange-correlation functional you use.}}


VASP allows setting the following tags in the {{FILE|INCAR}} file to change the vdW parameters used in DFT-D4.
VASP allows setting the following tags in the {{FILE|INCAR}} file to change the strength of the vdW interaction.
* {{TAG|DFTD4_MODEL}} : Dispersion model (available from VASP.6.6.0 onwards).
 
* {{TAG|DFTD4_XC}} : Functional name to determine the set of vdW parameters (available from VASP.6.6.0 onwards).
* {{TAG|VDW_S6}}, {{TAG|VDW_S8}} determine the strength of the dipole-dipole and dipole-quadrupole interaction.
* {{TAG|VDW_S6}} : Scaling of the dipole-dipole dispersion.
* {{TAG|VDW_A1}}, {{TAG|VDW_A2}} are scaling constants in the Becke-Johnson damping.
* {{TAG|VDW_S8}} : Scaling of the dipole-quadrupole dispersion.
* {{TAG|VDW_A1}} : Scaling of the critical radii in the Becke-Johnson rational damping.
* {{TAG|VDW_A2}} : Offset of the critical radii in the Becke-Johnson rational damping.
* {{TAG|VDW_S9}} : Scaling of the three-body dispersion energy (available from VASP.6.6.0 onwards).
* {{TAG|VDW_RADIUS}} : two-body interaction cutoff (available from VASP.6.6.0 onwards).
* {{TAG|VDW_CNRADIUS}} : coordination number cutoff (available from VASP.6.6.0 onwards).


== References ==
== References ==
Line 32: Line 26:
== Related tags and articles ==
== Related tags and articles ==
{{TAG|IVDW}},
{{TAG|IVDW}},
{{TAG|DFTD4_MODEL}},
{{TAG|DFTD4_XC}},
{{TAG|VDW_S6}},
{{TAG|VDW_S6}},
{{TAG|VDW_S8}},
{{TAG|VDW_S8}},
{{TAG|VDW_A1}},
{{TAG|VDW_A1}},
{{TAG|VDW_A2}},
{{TAG|VDW_A2}},
{{TAG|VDW_RADIUS}},
{{TAG|VDW_CNRADIUS}},
[[DFT-D3]],
[[DFT-D3]],
[[simple DFT-D3]],
[[Makefile.include#DFT-D4_.28optional.29|Linking to DFT-D4]]
[[Makefile.include#DFT-D4_.28optional.29|Linking to DFT-D4]]


[[Category:Exchange-correlation functionals]][[Category:Van der Waals functionals]][[Category:Howto]]
[[Category:Exchange-correlation functionals]][[Category:Van der Waals functionals]][[Category:Howto]]

Revision as of 09:40, 30 January 2026

DFT-D4 is an external package maintained by the Grimme group that can be linked to VASP. Read the documentation for more information about this package. DFT-D4 adds van-der-Waals (vdW) interactions to DFT because they are not included in most exchange-correlation functionals. It approximates the vdW interactions considering only the structure of the system which allows for a fast computation. Since every functional has different interactions between atoms, DFT-D4 tailors its adjustable parameters to the functional.

For more information regarding these parameters, please refer to the DFT-D4 paper.[1]

Usage

In most cases, it is sufficient to set IVDW=13 in the INCAR file if VASP was compiled and linked to DFT-D4. Internally, VASP passes the name of the used exchange-correlation functional to DFT-D4. Subsequently, DFT-D4 maps this name of the functional to optimized settings for the adjustable parameters of the vdW interaction. VASP uses these parameters to compute the DFT-D4 energies, forces, and stresses in every ionic step and adds them to the corresponding DFT terms. As a result, you can relax structures or run MD simulations with an approximate treatment of vdW interactions.

Warning: Below, we explain how to tweak the parameters of DFT-D4. Typically, you should not modify them unless you have a very good reason, e.g., because the interface is not implemented for the exchange-correlation functional you use.

VASP allows setting the following tags in the INCAR file to change the strength of the vdW interaction.

  • VDW_S6, VDW_S8 determine the strength of the dipole-dipole and dipole-quadrupole interaction.
  • VDW_A1, VDW_A2 are scaling constants in the Becke-Johnson damping.

References

  1. ↑ Template loop detected: Template:CiteTemplate loop detected: Template:CiteTemplate loop detected: Template:Cite E. Caldeweyher, J.-M. Mewes, S. Ehlert, and S. Grimme, Extension and evaluation of the D4 London-dispersion model for periodic systems, Phys. Chem. Chem. Phys. 22, 8499 (2020).

Related tags and articles

IVDW, VDW_S6, VDW_S8, VDW_A1, VDW_A2, DFT-D3, Linking to DFT-D4

Retrieved from "https://vasp.at/wiki/index.php?title=DFT-D4&oldid=33534"