DFT-D3

From VASP Wiki

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 ones):

  • 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 the damping function parameters are available for several GGA (PBE, RPBE, revPBE and PBEsol), METAGGA (TPSS, M06L and SCAN) and hybrid (B3LYP and PBEh/PBE0) functionals, as well as Hartree-Fock. If another functional is used, the user has to define these parameters via the 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 https://www.chemie.uni-bonn.de/grimme/de/software/dft-d3/ and follow the link "List of parametrized functionals").
  • 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. Also carefully check the more extensive list of references found on https://www.chemie.uni-bonn.de/grimme/de/software/dft-d3/.

Related tags and articles

VDW_RADIUS, VDW_CNRADIUS, VDW_S8, VDW_SR, VDW_A1, VDW_A2, IVDW, DFT-D2, DFT-D4

References