These are experimental features.
Two different approaches are implemented into FLEUR to include the London dispersion interactions or van der Waals forces.
- The DFT-D3 approach developed by Grimme Grimme S, Antony J, Ehrlich S and Krieg H 2010 J. Chem. Phys. 132 154104 allows to calculate contributions to the total energy and to the forces can be calculated.
- The method of Dion Dion M, Rydberg H, Schröder E, Langreth D C and Lundqvist B I 2004 Phys. Rev. Lett. 92 246401 yields a contribution to the total energy and also a contribution to the DFT potential.
These approaches can be controlled by the following switches
<expertModes vdW="NONE" vdw_tol="0.0005"/>
|vdW||"D3"||Use Grimme's D3 method|
|"Dion"||Use Dion's method for the total energy|
|"Dion,pot"||Also calculate Potential contribution|
|"Dion,core"||Subtract the core charge (if present) in Dion's method|
|"Dion,core,pot"||Combination of both switches|
|vdW_tol||0.0005||Energy cutoff for supercell effects in D3 method (eV)|