9529376 Lambrecht Many of the condensed matter systems (and also devices made from materials) with applications in the mesoscopic region, have a layered geometry. This proposal consists of a plan to calculate the electronic structure of these systems using a sophisticated, efficient algorithm. The computational effort, based on a difference equation in the layer indices, within the framework of the density functional theory using muffin-tin orbitals, scales with the number of layers (as opposed to the number of atoms). Following calculation of the one electron Green function for a mesoscopic system with atomic level precision, one can derive the self-consistent charge density, total energy, optical excitation energies and transport properties. The calculations will be carried out for group-III nitrides, SiC polytypes and rare earth based semimetal/semiconductor layered structures. %%% The popular man-made materials, in a variety of applications such as solid state lasers and magnetic memory devices, have a layered look. There is need for a calculation of their electronic properties. The novel approach to be used is particularly efficient and allows an atomic level understanding of the complex processes underlying the optical and magnetic properties of these systems.