van der Waals interactions in density functional theory using Wannier functions: Improved C6 and C3 coefficients by a different approach

A different implementation is proposed for including van der Waals interactions in density functional theory using the maximally localized Wannier functions. With respect to the previous DFT/vdW-WF method, the present DFT/vdW-WF2 approach, which is based on the simpler London expression and takes into account the intrafragment overlap of the localized Wannier functions, leads to a considerable improvement in the evaluation of the C-6 van der Waals coefficients, as shown by the application to a set of selected dimers. Preliminary results on Ar on graphite and Ne on the Cu(111) metal surface also suggest that the C-3 coefficients characterizing molecule-surfaces van der Waals interactions are better estimated with this scheme.