Temperature dependence of relaxation time of a stable radical pair in SyPixD investigated by pulsed EPR

摘要

The temperature dependence of the spin-lattice relaxation of the radical pair of flavin and tyrosine in SyPixD was investigated by pulsed electron paramagnetic resonance (EPR) spectroscopy. Biphasic recovery with a fast component of the spin-lattice relaxation time, denoted as T_(1fast), and slow component of spin-lattice relaxation time, denoted as T_(1slow), was detected in the range of 4-80 K. Based on the temperature dependence of T_(1fast) and T1slow below 16 K, the exchange coupling of the radical pair was estimated as 2J = 6-8 cm~(-1), defined as H=-2JS1S2.