SUPPRESSION AND ENHANCEMENT OF VAN-DER-WAALS INTERACTIONS

The van der Waals interaction of a pair of anisotropic molecules near planar dielectric surfaces is studied by using the linear response for malism. The spatial correlation function (Green function) of the vacuu m electric field in the presence of dielectric surfaces is obtained by using suitable Fresnel mode functions of the quantized electric field . In the short-distance limit, it is observed that the long-range inte raction potential is significantly modified by the dielectric surfaces and strongly depends on the geometry of the two molecules near dielec tric surfaces. When the two molecules are anisotropic, depending on th e molecular alignments with respect to the surfaces, the van der Waals interaction is enhanced or suppressed by the existence of the surface s. When the two molecules are in between two dielectric surfaces, the overall magnitude of the van der Waals interaction is suppressed in co mparison to that in the free space because the vacuum electromagnetic field intensity is reduced by the transmissivities that are generally less than unity. (C) 1996 American Institute of Physics.