Modeling Charge Transport and Dynamics in Biomolecular Systems

Abstract

Charge transport at the molecular scale builds the cornerstone of molecular electronics (ME), a novel paradigm aiming at the realization of nanoscale electronics via tailored molecular functionalities. Biomolecular electronics, lying at the borderline between physics, chemistry and biology, can be considered as a sub-field of ME. In particular, the potential applications of DNA oligomers either as template or as active device element in ME have strongly drawn the attention of both experimentalist and theoreticians in the past years. While exploiting the self-assembling and self-recognition properties of DNA based molecular systems is meanwhile a well-established field, the potential of such biomolecules as active devices is much less clear mainly due to the poorly understood charge conduction mechanisms. One key component in any theoretical description of charge migration in biomolecular systems, and hence in DNA oligomers, is the inclusion of conformational fluctuations and their coupling to the transport process. The treatment of such a problem affords to consider dynamical effects in a non-perturbative way in contrast to, e.g., conventional bulk materials. Here we present an overview of recent work aiming at combining molecular dynamic simulations and electronic structure calculations with charge transport in coarse-grained effective model R. Gutierrez and G. CunibertiHamiltonians. This hybrid methodology provides a common theoretical starting point to treat charge transfer/transport in strongly structurally fluctuating molecular-scale physical systems.

Optical properties and electronic transitions of DNA oligonucleotides as a function of composition and stacking sequence

“…9 While DNA has been considered as an example of a molecular wire, its capability to mediate charge transport via coherent tunneling and diffusive thermal hopping 10 depends crucially on the details of the experimental assay, sometimes yielding contradictory results. [11][12][13] Understanding the optical and electronic properties of DNA on a fundamental level provides the opportunity to advance materials design and function. 14 The combination of experimental and computational research in particular opens up the door toward realization of the rational materials design framework, which is guided by theory and informed by experiment.…”