Effects of sequential electron transfer on electron spin polarized transient EPR spectra at high fields

Effects of sequential electron transfer on electron spin polarized transient EPR spectra at high magnetic fields are investigated. Unlike the ordinary correlated radical pair model which neglects the effects of an intermediate radical pair, the sequential transfer mechanism becomes increasingly important at higher fields because of stronger singlet-triplet mixing due to a difference in the Zeeman interactions between the donor and the acceptor. Even if the intermediary radical pair has a lifetime of about 300 ps and is not directly detectable by EPR, noticeable changes in the polarized spectrum (at 95 and 250 GHz) of the subsequent radical pair are demonstrated.