Modeling Charge Transport and Dynamics in Biomolecular Systems

Charge transport at the molecular scale builds the cornerstone of molecularelectronics (ME), a novel paradigm aiming at the realization of nanoscaleelectronics via tailored molecular functionalities. Biomolecular electronics,lying at the borderline between physics, chemistry and biology, can be con-sidered as a sub-field of ME. In particular, the potential applications of DNAoligomers either as template or as active device element in ME have stronglydrawn the attention of both experimentalist and theoreticians in the past years.While exploiting the self-assembling and self-recognition properties of DNAbased molecular systems is meanwhile a well-established field, the poten-tial of such biomolecules as active devices is much less clear mainly due tothe poorly understood charge conduction mechanisms. One key componentin any theoretical description of charge migration in biomolecular systems,and hence in DNA oligomers, is the inclusion of conformational fluctuationsand their coupling to the transport process. The treatment of such a problemaffords to consider dynamical effects in a non-perturbative way in contrastto, e.g., conventional bulk materials. Here we present an overview of recentwork aiming at combining molecular dynamic simulations and electronicstructure calculations with charge transport in coarse-grained effective model Hamiltonians. This hybrid methodology provides a common theoretical start-ing point to treat charge transfer/transport in strongly structurally fluctuatingmolecular-scale physical systems.