Macroscopic and microscopic study of the planar vibrational mode coupling

We investigate the planar vibrational modes (PVMs) of a structure consistin g of two parallel slabs of a strange atom (X) inserted in a matrix of a bin ary material (AB). The study of the coupling of the PVMs has been undertake n with two different approaches. In the first model, the structure is descr ibed from a macroscopic point of view, characterizing the physical properti es of the constitutive materials by their layer densities, dielectric const ants and strain tensors. Adequate boundary conditions are imposed at the ma terial interfaces to obtain the vibrational modes of the structure. In the second model, the study of the planar modes is undertaken from a microscopi c point of view, by using a rigid ion model to calculate the vibrational ei genmodes of the structure. Different limiting cases are considered, discuss ing the suitability of the macroscopic model and relating the macroscopic a nd microscopic parameters.