Quantum mechanical spin dynamics of a molecular magnetoreceptor

Abstract

Radical pair recombination reactions are known to be sensitive to extremely weak magnetic fields, and can therefore be said to function as molecular magnetoreceptors. The classic example is a carotenoid-porphyrin-fullerene (C+PF-) radical pair that has been shown to provide a "proof-of-principle" for the operation of a chemical compass [K. Maeda et al., Nature 453, 387 (2008)]. Previous simulations of this radical pair have employed semiclassical approximations, which are routinely applicable to its 47 coupled electronic and nuclear spins. However, calculating the exact quantum mechanical spin dynamics presents a significant challenge, and has not been possible before now. Here we use a recently developed method to perform numerically converged simulations of the C+PF- quantum mechanical spin dynamics, including all coupled spins. Comparison of these quantum mechanical simulations with various semiclassical approximations reveals that, while it is not perfect, the best semiclassical approximation does capture essentially all of the relevant physics in this problem.

8 pages, 4 figures

References in corpus (6)

• An improved semiclassical theory of radical pair recombination reactions
• Asymmetric recombination and electron spin relaxation in the semiclassical theory of radical pair reactions
• Radical pair intersystem crossing: Quantum dynamics or incoherent kinetics?
• An efficient quantum mechanical method for radical pair recombination reactions
• Electron spin relaxation in radical pairs: Beyond the Redfield approximation
• Spin-dependent charge recombination along para-phenylene molecular wires

Cited by in corpus (2)

• Spin relaxation in radical pairs from the stochastic Schrödinger equation
• Simulation of nonequilibrium spin dynamics in quantum dots subjected to periodic laser pulses