Energetics of holes trapped in DNA

TL;DR

This study investigates the electronic properties of guanine traps in DNA, revealing conditions under which two holes can form a bound state due to the interplay of Coulomb repulsion and phonon-mediated attraction.

Contribution

It provides a detailed analysis of hole trapping in DNA and identifies the parameters that enable bound states of holes, advancing understanding of DNA's electronic behavior.

Findings

Two-hole bound states are possible in GGG and GGGG traps under certain conditions.

The formation of bound states depends on the balance between Coulomb repulsion and phonon-mediated attraction.

Bound states occur when hole-hole repulsion is less than approximately 0.9 eV at a coupling constant of about 1.

Abstract

We report on our study of the electronic properties of guanine traps in the DNA surrounded by adenines. We have shown that for a typical range of DNA parameters, formation of the bound state of two holes at the same guanine trap is possible for the GGG and GGGG traps if the hole-hole interaction is weak, which can be achieved for the DNA in solutions. The origin of the two-hole bound state is the competition between the Coulomb repulsion and the phonon mediated attraction between the holes. For the hole-phonon coupling constant $\approx 1$ two holes will be at the same trap if the on-site hole-hole repulsion energy is $\lesssim 0.9 $ eV.