Empirical damped dispersion corrections can be calculated in addition
to Kohn-Sham calculations. This is particularly important in cases
where long-range correlation effects become dominant.
17.5 Empirical damped dispersion correction
The dispersion correction can be added to the DFT energy by using
The total energy will then be calculated as
Currently the default dispersion correction added to the DFT energy
is the D3 dispersion correction developed by Grimme et al.,
see Ref. . The
disp keyword can have the following
- Functional name (default:
- Can have values 2 and 3 according to parametrisations
from Refs.  and  (default:
- Performs a detailed analysis of pair contributions.
- Cartesian gradients are computed. (note that
geometry optimisations with
are currently not yet possible).
- Use special parameters for calculations with
triple-zeta basis sets. Preliminary results in the SI of
Ref.  indicate that results are slightly worse than with
the default parameters and QZVP type basis sets. This option
should be carfully tested for future use in very large
http://toc.uni-muenster.de/DFTD3/index.html for further
Alternatively, the D3 dispersion correction can also be calculated
separately from the DFT calculation using the following template:
The older DFT-D1  or DFT-D2  methods by Grimme can still be used
with the following options to
- Adjusts the parametrisation used:
uses parameters from Ref.  and
uses parameters from Ref.  (default:
- Overall scaling parameter (see Eq. (34)
and Refs. [2,3] for optimised values).
- Damping function parameter (see Eq. (37)).
Smaller values lead to larger corrections for intermediate
In the DFT-D1 and DFT-D2 method the dispersion energy is calculated
is the total number of
atoms, is the interatomic distance of atoms and ,
is a global scaling parameter depending on the choice of the
functional used and the values are calculated
from atomic dispersion coefficients and in
the following way:
damps the dispersion correction for
shorter interatomic distances and is given by:
being the van-der-Waals radius for atom
and is a parameter that is usually set to 23 (Ref. )
or 20 (Ref. ).
S. Grimme, J. Antony, S. Ehrlich and H. Krieg, J. Chem. Phys. 132, 154104 (2010)
S. Grimme, J. Comp. Chem. 25, 1463 (2004).
S. Grimme, J. Comp. Chem. 27, 1787 (2006).