Counterion-mediated Electrostatic Interactions between Helical Molecules

TL;DR

This paper investigates how counterions influence electrostatic interactions between helical molecules, revealing new orientational effects in strong coupling regimes that differ from weak coupling predictions.

Contribution

It provides a detailed analysis of azimuthal dependence of interactions in both weak and strong coupling limits, highlighting novel orientational ordering phenomena.

Findings

Weak coupling shows negligible azimuthal dependence.

Strong coupling induces orientation-dependent interactions.

Identification of an optimal azimuthal configuration driven by correlation attraction.

Abstract

We study the interaction of two cylinders with helical charge distribution mediated by neutralizing counterions, by analyzing the separation as well as the azimuthal angle dependence of the interaction force in the weak and strong coupling limit. While the azimuthal dependence of the interaction in the weak coupling limit is overall small and mostly negligible, the strong coupling limit leads to qualitatively new features of the interaction, among others also to an orientationally dependent optimal configuration that is driven by angular dependence of the correlation attraction. We investigate the properties of this azimuthal ordering in detail and compare it to existing results.