Optical excitations in fractal antenna supermolecules with conjugated electrons: extended dendrimers

A coupled dipole model is proposed in order to characterize optical excitations in dendrimer supermolecules: the extended dendrimers. The dendrimer is composed of phenyl-ring vertexes and legs with phenyl rings and acetylene units. A transition dipole moment is assigned at each phenyl ring and the nearest-neighbor hopping integral is considered between the neighboring dipoles. The decreasing optical excitation energy with respect to the dendrimer size indicates the presence of exciton pathways along the backbone of the dendrimers.