Accurate Molecular Van Der Waals Interactions from Ground-State Electron Density and Free-Atom Reference Data
We present a parameter-free method for an accurate determination of long-range van der Waals interactions from mean-field electronic structure calculations. Our method relies on the summation of interatomic C6 coefficients, derived from the electron density of a molecule or solid and accurate reference data for the free atoms. The mean absolute error in the C6 coefficients is 5.5% when compared to accurate experimental values for 1225 intermolecular pairs, irrespective of the employed exchange-correlation functional. We show that the effective atomic C6 coefficients depend strongly on the bonding environment of an atom in a molecule. Finally, we analyze the van der Waals radii and the damping function in the C6R-6 correction method for density-functional theory calculations.
Physical Review Letters
- Pub Date:
- February 2009
- Exchange-correlation functionals;
- Density functional theory local density approximation gradient and other corrections;
- Theory modeling and computer simulation