Van der Waals Attraction in Multilayer Structures

The dispersion energy between multilayer systems is calculated from the energy of the electromagnetic field fluctuations, which originate in the interspace and are repeatedly reflected or transmitted by all interfaces. The resulting energy terms are summed explicitly for the case of a periodic double layer by means of combinatorial analysis. The dispersion energy between different layers turns out to be of longer range than that resulting from a pairwise integration of d^-6 interactions, on account of the large number of additional reflection terms. The reflection terms of order 1 ≥ 5 even show extremes in their dependence on the separation a₂. However, their generally decreasing weight makes it very unlikely that these extremes might also be encountered in the dispersion energy.