Center for Functional Nanomaterials Seminar

Van der Waals dispersion interactions are a non-local electron-electron correlation effect, that must be described by an appropriate electron density functional. Dion et al [2] have proposed such a true ab initio, universal and general-purpose vdW-DF functional, capable of describing quantitatively the week dispersion interactions, without compromising the accuracy of the best GGA functionals for stronger ionic, covalent and metallic bonds. Its new parametrization [3] provides even more accurate energies and equilibrium distances.
The direct evaluation of vdW-DF for large molecular systems is very expensive, however, because it requires a double integral in real space. We have presented [3] a new implementation that avoids this $N2$ scaling by applying Fourier convolution techniques to an accurately interpolated kernel. The resulting method scales as $N\log N$ and it allows to perform vdW-DF simulations of essentially any system that can be simulated with GGA.
We have applied the method to calculate binding energies and barriers of relative translation-rotation in double-wall carbon nanotubes and to H$_2$ adsorption in a nanoporous material [4]. It also provides a much improved description of liquid water [5] and clathrate hydrates [6] over that of GGA functionals.

References:
[1] Dion et al, PRL 92, 246401 (2004)
[2] K. Lee et al, PRB 82, 081101 (2010)
[3] G. Roman-Perez and J. M. Soler, PRL 103, 096102 (2009)
[4] Kong et al, PRL 103, 096103 (2009)
[5] J. Wang et al, JCP 134, 024516 (2011)
[6] G. Román-Pérez et al, PRL 105, 145901 (2010)