Module dispersion 

DFT-D4 Dispersion Correction — Core Module

Geometry-dependent London dispersion with Becke-Johnson damping. Provides C6/C8 two-body and optional ATM three-body corrections.

Relationship to other methods

• HF-3c: Uses D3-BJ internally; D4 is the next-generation replacement
• PM3: Can be augmented with D4 for non-covalent interactions
• xTB: GFN-xTB includes D4 natively; standalone D4 useful for EHT-D4
• UFF/MMFF94: D4 improves long-range dispersion accuracy

Reference

Caldeweyher, Ehlert, Hansen, Bauer, Spicher, Grimme, J. Chem. Phys. 150, 154122 (2019).

Structs

D4Config

D4 configuration.

D4Params

Per-element D4 parameters.

D4Result

Result of D4 dispersion calculation.

Functions

c8_from_c6

Compute C8 from C6 using the recursion relation.

compute_d4_energy

Compute D4 dispersion energy.

compute_d4_gradient

Compute numerical D4 gradient.

d4_coordination_number

Compute D4 fractional coordination number.

dynamic_c6

Get dynamic C6 adjusted by coordination number.

get_c6_reference

Get C6 reference for a pair using the London formula.

get_d4_params

Get D4 reference parameters by atomic number.