Becke-Johnson damping

Becke-Johnson damping needs an adjustment of an additional parameter (in the case of DFT-D3) but is more physically justified, as dispersion energy converges to a finite value when -> 0 [41] and allows to avoid some computational artifacts [37]. This approach improves non-covalent bond distances over zero-damping and significantly improves predictions of thermochemical properties. The approach indeed affects the short-range interaction covered by the underlying functionals but possible overcorrelation effects seem to cancel out for chemically relevant model systems [37]. 

Car-Parrinello molecular dynamics Grimme s third-generation dispersion correction with Becke-Johnson damping Density functional theory Empirically corrected DFT (functional or method)... 

The Q coefficients (and derived Cg) in the D3 method have been computed using a modified form of this relation, where the a(ia>) are computed nonempirically by TDDFT and A and B are reference molecules from which atomic values are derived [42]. Because the reference system can also be a molecular cluster modeling a solid environment, special coefficients for atoms in the bulk can be derived [68]. The final form for the DFT-D3 two-body part of the dispersion energy employs the so-called Becke-Johnson (BJ) damping [61, 69] and truncates the expansion at Cg... 

A few different alternatives have been proposed for the damping term. In a series of tests on systems particularly sensitive to dispersion, the different damping functions have similar effects. The damping function of Becke and Johnson leads to a dispersion energy term (for a particular order n)... 

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