Ftran at 16:43, 5 March 2026

2026-03-05T16:43:02Z

← Older revision		Revision as of 16:43, 5 March 2026
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	Simple DFT-D3{{cite\|ehlert:joss:2024}}{{cite\|sdftd3_1}}{{cite\|sdftd3_2}} is an external package that implements the DFT-D3 method{{cite\|grimme:jcp:10}}{{cite\|grimme:jcc:11}} and can be [[Makefile.include#simple-DFT-D3_.28optional.29\|linked to VASP]]. DFT-D3 adds to the DFT energy expression a term that accounts for the [[:Category:Van der Waals functionals\|van der Waals (vdW) interactions]], which are in principle not included in semilocal and hybrid exchange-correlation functionals. This is an approximation of the atom-pairwise type that depends only on the structure of the system, which allows for a fast computation. Since every functional has different interactions between atoms, DFT-D3 tailors its adjustable parameters to the functional.		Simple DFT-D3{{cite\|ehlert:joss:2024}}{{cite\|sdftd3_1}}{{cite\|sdftd3_2}} is an external package that implements the DFT-D3 method{{cite\|grimme:jcp:10}}{{cite\|grimme:jcc:11}} and can be [[Makefile.include#DFT-D4 and simple-DFT-D3_.28optional.29\|linked to VASP]]. DFT-D3 adds to the DFT energy expression a term that accounts for the [[:Category:Van der Waals functionals\|van der Waals (vdW) interactions]], which are in principle not included in semilocal and hybrid exchange-correlation functionals. This is an approximation of the atom-pairwise type that depends only on the structure of the system, which allows for a fast computation. Since every functional has different interactions between atoms, DFT-D3 tailors its adjustable parameters to the functional.
	For more information regarding these parameters, please refer to the DFT-D3 papers{{cite\|grimme:jcp:10}}{{cite\|grimme:jcc:11}} and simple DFT-D3 websites.{{cite\|sdftd3_1}}{{cite\|sdftd3_2}}		For more information regarding these parameters, please refer to the DFT-D3 papers{{cite\|grimme:jcp:10}}{{cite\|grimme:jcc:11}} and simple DFT-D3 websites.{{cite\|sdftd3_1}}{{cite\|sdftd3_2}}

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Simple DFT-D3{{cite|ehlert:joss:2024}}{{cite|sdftd3_1}}{{cite|sdftd3_2}} is an external package that implements the DFT-D3 method{{cite|grimme:jcp:10}}{{cite|grimme:jcc:11}} and can be [[Makefile.include#simple-DFT-D3_.28optional.29|linked to VASP]]. DFT-D3 adds to the DFT energy expression a term that accounts for the [[:Category:Van der Waals functionals|van der Waals (vdW) interactions]], which are in principle not included in semilocal and hybrid exchange-correlation functionals. This is an approximation of the atom-pairwise type that depends only on the structure of the system, which allows for a fast computation. Since every functional has different interactions between atoms, DFT-D3 tailors its adjustable parameters to the functional.
For more information regarding these parameters, please refer to the DFT-D3 papers{{cite|grimme:jcp:10}}{{cite|grimme:jcc:11}} and simple DFT-D3 websites.{{cite|sdftd3_1}}{{cite|sdftd3_2}}

Compared to the implementation in VASP of DFT-D3 ({{TAG|IVDW}}=11 and 12, see [[DFT-D3]]), the simple DFT-D3 package has some advantages:
*It offers more types of damping functions ({{TAG|SDFTD3_DAMPING}}).
*Allows to activate the three-body Axilrod–Teller–Muto term ({{TAG|VDW_S9}}).
*It has vdW parameters for elements up to lawrencium (<math>Z=103</math>), while it is up to plutonium (<math>Z=94</math>) in the VASP implementation.
*It is computationally faster.
{{NB|important|The use of simple DFT-D3 with VASP is available from VASP.6.6.0 onwards that needs to be compiled with -DSDFTD3.}}

== Usage ==

For some of the common exchange-correlation functionals (e.g., PBE, SCAN, or HSE06) it is sufficient to set {{TAG|IVDW}}=15 and {{TAG|SDFTD3_DAMPING}} for the damping function in the {{FILE|INCAR}} file. Internally, VASP passes automatically the name of the functional to simple DFT-D3. However, for other functionals the {{TAG|SDFTD3_XC}} tag has to be used to specify the functional to simple DFT-D3 (the names are listed in the file param.f90 of the simple DFT-D3 source code).
Subsequently, simple DFT-D3 maps the functional name to optimized settings for the adjustable parameters of the vdW interaction.
VASP uses these parameters to compute the DFT-D3 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|MD simulations]] with an approximate treatment of vdW interactions.
{{NB|important|Below, we explain how to tweak the parameters of DFT-D3. 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:
* {{TAG|SDFTD3_DAMPING}} : type of damping function.
* {{TAG|SDFTD3_XC}} : functional name to determine the set of vdW parameters.
* {{TAG|VDW_S6}} : scaling of the dipole-dipole dispersion.
* {{TAG|VDW_S8}} : scaling of the dipole-quadrupole dispersion.
* {{TAG|VDW_SR}} : scaling of the dipole-dipole damping.
* {{TAG|VDW_SR8}} : scaling of the dipole-quadrupole damping.
* {{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_BETA}} : offset for damping radius or power for the zero-damping component
* {{TAG|VDW_S9}} : scaling of the three-body dispersion energy.
* {{TAG|VDW_RADIUS}} : two-body interaction cutoff.
* {{TAG|VDW_CNRADIUS}} : coordination number cutoff.

== References ==
<references/>

== Related tags and articles ==
{{TAG|IVDW}},
{{TAG|SDFTD3_DAMPING}},
{{TAG|SDFTD3_XC}},
{{TAG|VDW_S6}},
{{TAG|VDW_S8}},
{{TAG|VDW_SR}},
{{TAG|VDW_SR8}},
{{TAG|VDW_A1}},
{{TAG|VDW_A2}},
{{TAG|VDW_BETA}},
{{TAG|VDW_S9}},
{{TAG|VDW_RADIUS}},
{{TAG|VDW_CNRADIUS}},
[[DFT-D3]],
[[DFT-D4]]

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

Simple-DFT-D3 - Revision history

Ftran at 16:43, 5 March 2026