Optical absorption in dendrimers

Dendrimers are highly branched molecules, which are expected to be useful, for example, as efficient artificial light harvesting systems, in nano-technological applications or in medical applications. There are two different classes of dendrimers: compact dendrimers with constant distance between neighboring branching points throughout the macromolecule and extended dendrimers, where this distance increases from the system periphery to the center. We investigate the linear optical absorption spectra of both families using the Frenkel exciton concept. In contrast to previous calculations we use two different models for extended dendrimers. The electron–phonon interaction is taken into account by introducing a heat bath that interacts with the exciton in a stochastic manner.