Boosting the magnetosensitivity of recombination reactions by radical scavenging

Scientific question: Can quantum effects in three-spin systems be used to vastly amplify the sensitivity of radical reactions to weak magnetic fields? Synopsis: Radical pair reactions are sensitive to weak magnetic fields. Remarkably, this is the result of truly quantum effects, which operate under conditions where the corresponding classical effects would be entirely negligible. This phenomenon likely underlies animal magnetoreception and has been discussed in the context of potentially adverse health effects related to weak magnetic field exposure. Often these effects are small, particularly for the magnetic field intensities encountered in our everyday surroundings. Understanding how these effects can be inherently amplified is the most pressing puzzle of quantum biology. Hypotheses: Recently, one of us has proposed an additional reaction pathway as part of the avian magnetic compass that acts to vastly amplify magnetic field effects (MFEs). This new mechanism relies on the spin-selective reaction of the usual radical pair with another, external, radical, which we refer to as a scavenger. As a consequence of the chemical Zeno effect, this process could provide unparalleled magneto-sensitivity. This project aims to afford the first experimental evidence of this amplification process. To this end, we will adapt a transient absorption spectrometer in Geneva to accommodate magnetic field-dependent measurements. This will allow us to detect directly the predicted peculiarities of MFEs in self-assembled three-radical systems. While we will only be able to realize a proof-of-principle realisation within this project, our efforts will allow us to collect pilot data for larger grant applications. Participants Prof. Eric Vauthey, University of Geneva Dr. Daniel Kattnig, University of Exeter