We show that the stochastic Schrödinger equation (SSE) provides an ideal way to simulate
the quantum mechanical spin dynamics of radical pairs. Electron spin relaxation effects
arising from fluctuations in the spin Hamiltonian are straightforward to include in this
approach, and their treatment can be combined with a highly efficient stochastic evaluation
of the trace over nuclear spin states that is required to compute experimental observables.
These features are illustrated in example applications to a flavin–tryptophan radical pair of …