Quantum measurement corrections to CIDNP in photosynthetic reaction centers

TL;DR

This paper reveals that quantum decoherence in radical-ion-pair reactions can produce extremely high nuclear spin polarizations, offering new insights into CIDNP signals in photosynthetic reaction centers.

Contribution

It demonstrates that quantum measurement effects in radical pairs significantly enhance CIDNP signals, a novel perspective in understanding spin dynamics in photosynthesis.

Findings

Decoherence mechanism produces nuclear polarization 10^4 times above thermal equilibrium.

Quantum dynamics of radical pairs can generate unexpectedly high CIDNP signals.

Potential to explore biological significance of high nuclear polarization in photosynthesis.

Abstract

Chemically induced dynamic nuclear polarization is a signature of spin order appearing in many photosynthetic reaction centers. Such polarization, significantly enhanced above thermal equilibrium, is known to result from the nuclear spin sorting inherent in the radical pair mechanism underlying long-lived charge-separated states in photosynthetic reaction centers. We will here show that the recently understood fundamental quantum dynamics of radical-ion-pair reactions open up a new and completely unexpected venue towards obtaining CIDNP signals. The fundamental decoherence mechanism inherent in the recombination process of radical pairs is shown to produce nuclear spin polarizations on the order of $10^4$ times or more higher than the thermal equilibrium value at earth's magnetic field relevant to natural photosynthesis. This opens up the possibility of a fundamentally new exploration of the biological significance of high nuclear polarizations in photosynthesis.