Electronic structure of overstretched DNA

TL;DR

This paper investigates how extreme stretching of DNA affects its electronic properties, revealing a significant decrease in conductivity due to reduced electronic coupling between states.

Contribution

It provides quantum mechanical calculations and a visualization method to analyze the electronic structure changes in overstretched DNA, a novel approach in this context.

Findings

Overstretching causes a 90% elongation of DNA.

Hopping matrix elements between electronic states drop significantly.

Conductivity through holes decreases dramatically upon overstretching.

Abstract

Minuscule molecular forces can transform DNA into a structure that is elongated by more than half its original length. We demonstrate that this pronounced conformational transition is of relevance to ongoing experimental and theoretical efforts to characterize the conducting properties of DNA wires. We present quantum mechanical calculations for acidic, dry, poly(CG).poly(CG) DNA which has undergone elongation of up to 90 % relative to its natural length, along with a method for visualizing the effects of stretching on the electronic eigenstates. We find that overstretching leads to a drastic drop of the hopping matrix elements between localized occupied electronic states suggesting a dramatic decrease in the conductivity through holes.