Electrons in Dry DNA from Density Functional Calculations

TL;DR

This study uses density functional calculations to analyze the electronic structure of dry DNA, revealing limited prospects for coherent electron transport but potential for diffusive conduction.

Contribution

It provides a detailed computational analysis of electron transport properties in dry DNA, offering insights into conduction mechanisms and model parameters.

Findings

Coherent electron transport in dry DNA is highly unlikely.

Energy band widths are too narrow compared to vibrational fluctuations.

Diffusive transport with sub-nanometer mean free paths remains possible.

Abstract

The electronic structure of an infinite poly-guanine - poly-cytosine DNA molecule in its dry A-helix structure is studied by means of density-functional calculations. An extensive study of 30 nucleic base pairs is performed to validate the method. The electronic energy bands of DNA close to the Fermi level are then analyzed in order to clarify the electron transport properties in this particularly simple DNA realization, probably the best suited candidate for conduction. The energy scale found for the relevant band widths, as compared with the energy fluctuations of vibrational or genetic-sequence origin, makes highly implausible the coherent transport of electrons in this system. The possibility of diffusive transport with sub-nanometer mean free paths is, however, still open. Information for model Hamiltonians for conduction is provided.