oxalate or H2edta(2-) in not given Kinetics; Irradiation (UV/VIS); under oxygen-free Ar atmosphere, 5-10 fold excess of Co(III)-complex, ionic strength 0.15M, pH 5.8, laser flash photolysis (ambient temp.), quenching by oxalate or H2edta(2-); UV/VIS monitoring (480 or 685 nm);