Ultrafast dynamics of the excited methylviologen–iodide charge transfer complexes

The ultrafast dynamics of the excited charge transfer complexes between methylviologen and iodide ions has been investigated in aqueous solutions of potassium iodide using femtosecond transient absorption spectroscopy. Methylviologen and iodide form 1:1 and 1:2 charge transfer complexes characterized by charge transfer bands in the same spectral region. Transient absorption of the complexes has been studied after ultrafast excitation in their charge transfer band. The excitation of the 1:1 complex results in the formation of the MV+/I radical pair while the excitation of the 1:2 complex is leading to the formation of the MV+/I and MV+/I2 radical pairs.