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 …