Quantum Charge Transport and Conformational Dynamics of Macromolecules

TL;DR

This paper develops a formalism combining molecular and quantum dynamics to study charge transport in macromolecules, revealing how conformational changes affect quantum localization during polymer collapse.

Contribution

It introduces a coupled equations of motion for molecular and quantum transport dynamics and an algorithm for identifying dominant pathways in thermally-activated reactions.

Findings

Charge transport is quenched in molten globule states.

Quantum localization increases with dynamical disorder during collapse.

The formalism accurately models charge dynamics in conformational transitions.

Abstract

We study the dynamics of quantum excitations inside macromolecules which can undergo conformational transitions. In the first part of the paper, we use the path integral formalism to rigorously derive a set of coupled equations of motion which simultaneously describe the molecular and quantum transport dynamics, and obey the fluctuation/dissipation relationship. We also introduce an algorithm which yields the most probable molecular and quantum transport pathways in rare, thermally-activated reactions. In the second part of the paper, we apply this formalism to simulate the propagation of a charge during the collapse of a polymer from an initial stretched conformation to a final globular state. We find that the charge dynamics is quenched when the chain reaches a molten globule state. Using random matrix theory we show that this transition is due to an increase of quantum localization driven by dynamical disorder.