Analytical calculations of EPR signal intensities for radical pairs at reaction centers of photosynthesis in high MW fields

Analytical expressions for time-dependent EPR signals of radical pairs at p hotosynthesis reaction centers in high mw fields are derived based on the a ssumption of selective excitation of two nearby resonance transitions. The criteria are proposed for assessing the accuracy of the analytical expressi ons for line intensities in EPR spectra of radical pairs at photosynthesis reaction centers. The analytical expressions are compared with the results of exact numerical calculations. It is shown that the analytical expression s approximate remarkably closely the intensities of EPR lines at typical va lues of magnetic resonance parameters of radical pairs at photosynthesis re action centers and at typical values of mw field amplitudes used in EPR exp eriments.