Many-body effects of dispersion interaction.

The role of many-body (MB) dispersion forces have been analyzed for strands, films, and cubic lattices in the framework of a model Hamiltonian that allows exact solution of the multiparticle Shrodinger equation. For the systems investigated the MB contribution may be as large as 7% of specific dispersion energy and 11% of solvation energy. Nonadditivity becomes particularly important for aggregation in solution, where its effect may be several times larger than the pairwise contribution. For all systems considered, the three-body Axilrod-Teller approximation was insufficient to predict the magnitude and in some cases even the sign of the full MB effect.