Dipole relaxation losses in DNA

TL;DR

This study investigates the electrodynamic response of DNA in the millimeter wave range, revealing that its AC conductivity arises from dipole dissipation in water rather than photon hopping, explaining the discrepancy between DC and AC conductivity.

Contribution

It demonstrates that DNA's AC conductivity is due to dipole motion in water, not photon-activated hopping, clarifying the mechanism behind DNA's electrodynamic response.

Findings

AC conductivity of DNA is due to dipole dissipation in water

Dissipation mechanism explains the difference between DC and AC conductivity

Water's role in DNA's electrodynamic response is crucial

Abstract

The electrodynamic response of DNA in the millimeter wave range is investigated. By performing measurements under a wide range of humidity conditions and comparing the response of single strand DNA and double strand DNA, we show that the appreciable AC conductivity of DNA is not due to photon activated hopping between localized states, but instead due to dissipation from dipole motion in the surrounding water helix. Such a result, where the conductivity is due to the constrained motion of overdamped dipoles, reconciles the vanishing DC conductivity of DNA with the considerable AC response.