Spin properties of paramagnetic centers generated under irradiation of crystalline complexes of C60 with triphenylamine

EPR spectra of paramagnetic centers formed in crystals of C60 complexes wit h triphenylamine exposed to visible light are recorded in three-centimeter and two-millimeter spectral ranges. Convincing evidence for the existence o f two kinds of paramagnetic centers with different relaxation and dynamic p arameters is gained. Rotation of C60 molecules in C60/triphenylamine crysta ls at low temperatures is an activated process accelerating dramatically up on phase transition. This transition is accompanied by changes in electron relaxation and paramagnetic susceptibility of the system. Rotation frequenc y of the molecules depends on the size of a unit cell of the complex and on the triphenylamine conformation.