Polaron tunneling dynamics in the DNA molecule

TL;DR

This paper investigates polaron formation and tunneling in DNA molecules using a semiclassical model, revealing how sequence-dependent charge-phonon interactions influence tunneling rates and mechanisms.

Contribution

It introduces a method to determine charge-phonon coupling constants in DNA and analyzes how sequence variations affect polaron tunneling dynamics.

Findings

Charge-phonon coupling is stronger in G-C pairs than A-T pairs.

Tunneling rates vary up to seven orders of magnitude with trap position.

Sequence dependence significantly influences polaron tunneling behavior.

Abstract

The formation of polaron and its migration in a DNA chain are studied within a semiclassical Peyrard-Biship-Holstein polaron model. Comparing the energetics of the polaron system found from the quantum chemical and semiclassical calculations, we extract the charge-phonon coupling constant for poly DNA sequences. The coupling constant is found to be larger for the G-C than for the A-T pairs. With this coupling constant we study tunneling in the DNA molecule. The rates and the nature of tunneling have strong dependence on the DNA sequence. By changing the trap positions in the molecular bridge the tunneling rate can by varied up to seven orders of magnitude.