On the surface effect in thin molecular or composite layers

The electromagnetic properties of thin dielectric or composite layers are c onsidered. We study the case when the thickness d of a slab is so small tha t only a few particles forming the effective medium are located on the inte rval d. A novel approach to the quasistatic modelling of the local field ac ting on a particle is suggested. In this case the local "permittivity" near the upper and lower surfaces of the slab differs from the bulk permittivit y of the same material, This can influence the reflection and transmission properties of the slab. Even if the particles are isotropically polarizable or are randomly oriented in the slab volume, this thin structure has aniso tropic (uniaxial) electromagnetic properties.