Nonretarded van der Waals Interaction between Anisotropic Long Thin Rods at All Angles

Abstract

The nonretarded van der Waals interaction between anisotropic long thin rods in an isotropic medium is formulated for parallel and skewed orientations. The results are obtained by considering the interaction between two composite media in which arrays of rods are embedded. This interaction may be written directly using the theory of van der Waals forces between anisotropic materials. As a function of rod density, the leading term in the total interaction is that between pairs of rods in the two media. A test function for this rod-rod interaction is summed over all pairs and equated to the known total interaction of all rods. This result retains all many-body properties of the van der Waals interaction. A method for computation using dielectric birefringence data is also described. Two restrictive criteria are developed for deciding when the interaction of rods in an array will be the sum of individual rod-rod interactions.