Electron dynamics in dendrimers

Electron transfer dynamics in -extensively branched macromolecules (dendrimers) is studied using time-dependent quantum mechanical techniques. A split operator method that fully exploits the Cayley tree topology of these macromolecules is developed within a tight binding model Hamiltonian. Solvent effects are simulated by time-dependent random fluctuations; this dephasing eliminates the localized oscillations that characterize the nonsolvated dynamics, and results in decay of the electron density from an initially photoexcited state. Electron transfer is asymmetric depending on the site of initial excitation, and solvent fluctuations in general enhance the directed transport within the structure. Some dendrimers, particularly those with a certain extended structures show enhanced transport toward their central nodes. The efficiency of electron transfer to the central node depends on both the dendrimer structure and the characteristics of the solvent fluctuations.