Distance-dependent charge transfer mechanism in adenine bridging DNA sequences

Long-range DNA charge transfer process has been investigated on 5′-G(A)nG3-3′ sequences by varying the number of adenine bridging base pairs. The charge transfer mechanism was determined based on density matrix decomposition path integration and trajectory analysis. The density matrix decomposition path integral formalism provides relative contribution of possible CT mechanisms such as incoherent hopping, coherent through-bridge, and superexchange mechanism. Quantitative determination of the degree-of-coherence in terms of the coherence length is useful in specifying the through-bridge mechanism, since it indicates the subset of states which forms a coherent collective state. In addition, trajectory analysis was performed to provide detailed description of the coherence propagation between distant states.