Quantum Theory of Radical-Ion-Pair Recombination: A New Physical Paradigm for Low-Magnetic-Field Effects

TL;DR

This paper introduces a quantum-mechanical framework for understanding radical-ion-pair recombination, explaining low-field magnetic effects and experimental observations that classical theories cannot account for.

Contribution

It presents a novel quantum theory of radical-ion-pair recombination as a continuous quantum measurement, bridging it with classical models at high fields.

Findings

Quantum phenomena dominate at low magnetic fields.

Deuteration affects magnetic sensitivity in radical-ion-pair reactions.

The new theory explains experimental results incompatible with classical models.

Abstract

A new paradigm emerging in the description of magnetic-sensitive radical-ion-pair recombination reactions is presented. This paradigm is founded on the realization that the recombination process of radical-ion pairs is a continuous quantum measurement. In the regime of low magnetic fields we describe the appearance of purely quantum phenomena, that fade away as the magnetic field increases. We will analyze the magnetic sensitivity of these reactions under this perspective and bridge the new full quantum theory with the existing classical reaction theory applicable at high magnetic fields. Based on the quantum theory of recombination we will then explain experimental observations incompatible with classical reaction theory, in particular the effect of deuteration on the magnetic sensitivity of radical-ion pair recombination yields.