Publication: Charge transfer mechanisms in DNA at finite temperatures: from quasiballistic to anomalous subdiffusive charge transfer
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American Physical Society
We address various regimes of charge transfer in DNA within the framework of the Peyrard-Bishop-Holstein model and analyze them from the standpoint of the characteristic size and timescales of the electronic and vibrational subsystems. It is demonstrated that a polaron is an unstable configuration within a broad range of temperatures and therefore polaronic contribution to the charge transport is irrelevant. We put forward an alternative fluctuation-governed charge transfer mechanism and show that the charge transfer can be quasi -ballistic at low temperatures, diffusive or mixed at intermediate temperatures, and subdiffusive close to the DNA denaturation transition point. Dynamic fluctuations in the vibrational subsystem is the key ingredient of our proposed mechanism which allows for explanation of all charge transfer regimes at finite temperatures. In particular, we demonstrate that in the most relevant regime of high temperatures (above the aqueous environment freezing point), the electron dynamics is completely governed by relatively slow fluctuations of the mechanical subsystem. We argue also that our proposed analysis methods and mechanisms can be relevant for the charge transfer in other organic systems, such as conjugated polymers, molecular aggregates, alpha-helices, etc.
©2022 American Physical Society This work was partially supported by CNPq, CAPES (Grant No. PVE-A121) and FINEP (Federal Brazilian Agencies) , as well as FAPEAL (Alagoas State Agency) and Spanish MINECO Grants No. MAT2013-46308 and No. MAT2016-75955. A.V.M. is grateful to the Universidade Federal de Alagoas (where a part of this work has been carried out) for hospitality. R.P.A.L. is grateful to the Universidad Complutense de Madrid and Warwick University (where a part of this work has been carried out) for hospitality. The authors also thank V. A. Malyshev for critical reading of the manuscript and acknowledge the crucial contribution of J. Munarriz to numerical calculations of the system dynamics.