Strategies for state space restriction in densely coupled spin systems with applications to spin chemistry.

We propose three basis screening methods for state space restriction in Liouville space simulations of large densely coupled spin systems encountered in electron paramagnetic resonance (EPR) spectroscopy and spin chemistry. The methods are based on conservation law analysis, symmetry factorization, and the analysis of state space connectivity graphs. A reduction in matrix dimensions by several orders of magnitude is demonstrated for common EPR and spin chemistry systems.