A Manifestation of two-quantum transitions in the ODEPR spectra of the spin-correlated radical pairs in micelles

Optically detected electron paramagnetic resonance spectra of the spin-correlated radical pairs diffusing inside a spherical region are numerically simulated taking into account an exchange interaction between partners of the pairs. It is shown that these spectra contain the lines induced by the two-quantum transitions. The shape and the width of this two-quantum transition line are analyzed as depending on magnetic resonance parameters, on molecular kinetic parameters and chemical reactivity of radicals.