The effect of spin relaxation on ESR spectra of spin correlated radical pairs

The effect of spin relaxation on time resolved ESR spectra of spin-correlated radicals pairs is analyzed within the exponential stochastic Liouville equation approach. The shapes and amplitudes of spectra are shown to considerably change as a spin dephasing rate increases to values of order of the difference of Zeeman frequencies of radicals. In particular, antiphase structures of different lines merge in one of the opposite line located at the center of spectrum.