DFT-D3: Difference between revisions

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with <math>s_6=1</math> and <math>a_1</math>, <math>a_2</math>,  and <math>s_8</math> being adjustable parameters.
with <math>s_6=1</math> and <math>a_1</math>, <math>a_2</math>,  and <math>s_8</math> being adjustable parameters.
This variant of DFT-D3 method (DFT-D3(BJ)) is invoked by setting {{TAG|IVDW}}=12. As before, the parameters {{TAG|VDW_RADIUS}} and {{TAG|VDW_CNRADIUS}} can be used to change default values for cutoff radii. The parameters of the damping function can be controlled using the following tags:
This variant of DFT-D3 method (DFT-D3(BJ)) is invoked by setting {{TAG|IVDW}}=12. As before, the parameters {{TAG|VDW_RADIUS}} and {{TAG|VDW_CNRADIUS}} can be used to change the default values for the cutoff radii. The parameters of the damping function can be controlled using the following tags:


*{{TAG|VDW_S8}}=[real]
*{{TAG|VDW_S8}}=[real]

Revision as of 12:54, 19 July 2022

In the DFT-D3 method of Grimme et al.[1], the following expression for the vdW-dispersion energy-correction term is used:

Unlike in the method DFT-D2, the dispersion coefficients are geometry-dependent as they are adjusted on the basis of the local geometry (coordination number) around atoms and . In the zero-damping variant of the DFT-D3 method (DFT-D3(zero)), the damping function reads:

where , the parameters , , and are fixed at values of 14, 16, 1, and 1, respectively, while and are adjustable parameters whose values depend on the choice of the exchange-correlation functional. The DFT-D3(zero) method is invoked by setting IVDW=11. Optionally, the following parameters can be user-defined (the given values are the default values):

  • VDW_RADIUS=50.2 : cutoff radius (in ) for pair interactions considered in the equation of
  • VDW_CNRADIUS=20.0 : cutoff radius (in ) for the calculation of the coordination numbers
  • VDW_S8=[real] : damping function parameter
  • VDW_SR=[real] : damping function parameter

Alternatively, the Becke-Johnson (BJ) damping can be used in the DFT-D3 method[2]:

with and , , and being adjustable parameters. This variant of DFT-D3 method (DFT-D3(BJ)) is invoked by setting IVDW=12. As before, the parameters VDW_RADIUS and VDW_CNRADIUS can be used to change the default values for the cutoff radii. The parameters of the damping function can be controlled using the following tags:


Mind: The default values for damping function parameters are available for the following functionals: PBE (GGA), RPBE (GGA), revPBE (GGA) and PBEsol (GGA). If another functional is used, the user must define these parameters via corresponding tags in the INCAR file. The up-to-date list of parametrized DFT functionals with recommended values of damping function parameters can be found

on the webpage http://www.thch.uni-bonn.de/tc/dftd3.

Mind: The DFT-D3 method has been implemented in VASP by Jonas Moellmann based on the dftd3 program written by Stefan Grimme, Stephan Ehrlich and Helge Krieg. If you make use of the DFT-D3 method, please cite reference [1]. When using DFT-D3(BJ) references [1] and [2] should also be cited.


Related tags and articles

IVDW, IALGO, DFT-D2, Tkatchenko-Scheffler method, Tkatchenko-Scheffler method with iterative Hirshfeld partitioning, Self-consistent screening in Tkatchenko-Scheffler method, Many-body dispersion energy, dDsC dispersion correction

References