Dispersion Coefficients for van der Waals Complexes, Including C₆₀–C₆₀

Abstract

A previously proposed and tested (1996 Phys. Rev. Lett. 76 102; 1996 Phys. Rev. Lett. 77 2029) van der Waals density functional is applied to van der Waals complexes. Dynamic polarizabilities, α(iu), and dispersion coefficients, C6, are obtained with a useful accuracy and at a low computational cost using ground-state electron densities as input. We compare results for C6 for small and medium-sized molecules with existing results obtained using more cumbersome methods. The computational simplicity of the functional opens up the possibility to treat large systems of real interest within different fields of physics, chemistry and biology. This is illustrated by the application to C60. We present results for the static polarizability α0 and the dispersion coefficient C6 for two such molecules.