  Chemically induced dynamic nuclear polarization is a ubiquitous phenomenon in
photosynthetic reaction centers. The relevant nuclear spin observables are a
direct manifestation of the radical-pair mechanism. We here use quantum
trajectories to describe the time evolution of radical-pairs, and compare their
prediction of nuclear spin observables to the one derived from the radical-pair
master equation. While our approach provides a consistent description, we
unravel a major inconsistency within the conven- tional theory, thus
challenging the theoretical interpretation of numerous CIDNP experiments
sensitive to radical-pair reaction kinetics.
