Triplet line shape simulation in continuous wave electron paramagnetic resonance experiments

We present a simple yet powerful method of simulating continuous wave electron spin resonance line shape of triplets in frozen and liquid solutions. The analysis enables one to consider cases such as immobilized triplets with random distribution, anisotropic slow and fast rotation of the triplet molecules, exchange between triplets with different Hamiltonians, anisotropic relaxation rates, and triplets with non-Boltzmann population distribution of the spin levels. Theoretical basis for the method is provided, along with several examples of simulated and experimental spectra for various physical conditions. A short "Matlab" routine, which can be used in the numerical spectra simulation, is given in the Appendix. (c) 2005 Wiley Periodicals, Inc.